e. coli and phased benthic total maximum daily load ......daniel boone soil and water conservation...

E. coli and Phased Benthic Total Maximum Daily Load

Development for Powell River and Tributaries (N.F. Powell River, S.F.

Powell River, Butcher Fork, and Wallen Creek)

Prepared for: Virginia Department of Environmental Quality

Contract # 14121

February 2011

Submitted by:

MapTech, Inc. New River Highlands RC&D 3154 State Street 100 USDA Drive, Suite F Blacksburg, VA 24060 Wytheville, VA 24382 (540) 961-7864

New River-Highlands RC&D

TMDL Development Powell River and Tributaries, VA

TABLE OF CONTENTS i

ACKNOWLEGEMENTS

Virginia Department of Environmental Quality (VADEQ), Central Office

VADEQ, Southwestern Regional Office

Virginia Department of Mines, Mineral and Energy (DMME)

Virginia Department of Conservation and Recreation (VADCR)

Daniel Boone Soil and Water Conservation District (SWCD)

Lonesome Pine Soil and Water Conservation District (SWCD)

Virginia Department of Health

Watershed citizens


PREFACE iii

PREFACE – PHASED TMDL FOR THE POWELL RIVER

In order to meet the U. S. Environmental Protection Agency’s (EPA) May 1, 2010

deadline, Virginia agencies have been working diligently to complete Total Maximum

Daily Load (TMDL) studies for several segments of the Powell River. The following

draft report represents the product of the state’s efforts to date. During development,

uncertainties and differences of interpretation regarding report narrative, report format,

data, and predictive tools were identified. Assistance with the TMDL was solicited from

the U. S. Office of Surface Mining, U. S. EPA, and private contractors. Some concerns

regarding the sufficiency of the available data’s ability to determine pollution load

reductions and the adequacy of the predictive tools being utilized remain. Additional

monitoring is needed to resolve the uncertainties and differences. Therefore, the report is

being presented as a “phased” TMDL in accordance with EPA guidance and the state will

utilize an adaptive management approach.

PHASED TMDL

A revised TMDL document will be developed by the Virginia Department of

Environmental Quality (DEQ) and the Virginia Department of Mines, Minerals, and

Energy’s Division of Mined Land Reclamation (DMLR). The revised TMDL is planned

for submittal to EPA two years from the date that both the U. S. EPA Region III has

approved and the Virginia State Water Control Board (SWCB) has adopted the “phased”

Powell River TMDL. DMLR will take the lead role with the revisions.

Adaptive implementation is an iterative implementation process that moves toward

achieving water quality goals while collecting, and using, new data and information. It is

intended to provide time to address uncertainties with TMDLs and make necessary

revisions while interim water quality improvements are initiated.

A monitoring plan and experimentation for model refinement will be implemented by the

DEQ and DMLR during the period of time beginning with the submittal to EPA of this

DRAFT until the preparation of the revised TMDL submittal to EPA.


iv PREFACE

At a minimum, the plan will include monitoring to accomplish the following:

Better quantify sediment contributions to the watershed from active mining operations during larger storm events and,

To gather additional data on PAHs.

INTERIM ACTIONS

The following interim actions will be implemented immediately upon both the approval

of the TMDL by EPA and adoption of the TMDL by the SWCB:

All Waste Load Allocations in this TMDL will be effective and implemented by DMLR.

EPA regulations require that an appropriate TMDL include individual WLAs for each

point source. According to 40 CFR §122.44(d)(1)(vii)(B), Effluent limits developed to

protect a narrative water quality criterion, a numeric water quality criterion, or both, shall

be consistent with assumptions and requirements of any available WLA for the discharge

prepared by the state and approved by EPA pursuant to 40 CFR §130.7.

DMLR will utilize its existing TMDL processes and software to maintain or decrease

existing pollution wasteloads from active mining for sediment (TSS). DMLR will also

restrict additional mining, through the use of offset requirements, to collective pollution

loads equal to or below current wasteloads. DEQ will permit non-coal dischargers in

compliance with wasteload allocations included in the TMDL and the agencies’ current

policies and procedures.

Although additional monitoring data, modeling refinements, allocations for pollutants,

and long-term implementation actions will be part of the revised TMDL, on-going, long-

term efforts to improve the watershed as described below will continue.

The elimination or reduction of pollution loads from abandoned coal mined lands (AML) is typically necessary for the state to meet the allocations prescribed in Virginia’s resource extraction TMDLs. DMLR’s efforts to eliminate and reduce pollution from AML will continue in the TMDL watershed.

DMLR will utilizes AML Program Funding, including the U. S. Office of Surface

Mining’s annual AML grants, Clean Streams Initiative, and Acid Mine Drainage set-aside provisions, to remediate AML problems within the watersheds.

DMLR recognizes that assistance is needed with AML reclamation and will encourage

assistance from Virginia’s active coal mining industry. Several approaches, consistent


PREFACE v

with this recognition, will be implemented including re-mining, Rahall permits, AML enhancements, and TMDL offsets.

TMDL offsets will provide for mine discharge permit applicants to reclaim existing AML

features within the watershed to create a water pollution offset for proposed coal mining activity. The offsets will be required to contain a positive ratio for pollution reduction and to eliminate permanent pollutant sources for temporary pollution credit.


TABLE OF CONTENTS vii

TABLE OF CONTENTS

ACKNOWLEGEMENTS.................................................................................................... i

PREFACE – PHASED TMDL FOR THE POWELL RIVER PHASED TMDL ............. iii

INTERIM ACTIONS......................................................................................................... iv

TABLE OF CONTENTS.................................................................................................. vii

LIST OF FIGURES .......................................................................................................... xv

LIST OF TABLES.......................................................................................................... xxv

EXECUTIVE SUMMARY ........................................................................................ xxxvii

Background and Applicable Standards................................................................... xxxvii

TMDL Endpoint and Water Quality Assessment .................................................... xxxix

Source Assessment .................................................................................................. xxxix

Modeling Procedures ............................................................................................... xxxix

Hydrology ...................................................................................................................... xl

Fecal Coliform ............................................................................................................... xl

Sediment ....................................................................................................................... xli

Load Allocation Scenarios........................................................................................... xlii

Implementation ...........................................................................................................xliii

Public Participation..................................................................................................... xliv

1. INTRODUCTION .....................................................................................................1-1

1.1 Regulations Background.................................................................................. 1-1

1.2 Powell River Watershed Characteristics.......................................................... 1-2

1.3 Powell River Impairments ............................................................................... 1-4

1.3.1 Butcher Fork (VAS-P18R_BUH01A04) ..................................................... 1-4

1.3.2 South Fork Powell River (VAS-P18R_PLL01A98).................................... 1-5




viii TABLE OF CONTENTS

1.3.5 North Fork Powell River (VAS-P20R_PWL01A00) .................................. 1-6

1.3.6 Wallen Creek (VAS-P22R_WAL01A00).................................................... 1-7

1.3.7 Powell River................................................................................................. 1-7

2. TMDL ENDPOINT AND WATER QUALITY ASSESSMENT.............................2-1

2.1 Applicable Water Quality Standards ............................................................... 2-1

2.2 Selection of a TMDL Endpoint........................................................................ 2-2

2.3 Discussion of In-stream Water Quality............................................................ 2-3

2.3.1 Inventory of Water Quality Monitoring Data .............................................. 2-3

3. BACTERIA SOURCE ASSESSMENT ....................................................................3-1

3.1 Assessment of Permitted Sources .................................................................... 3-1

3.2 Assessment of Nonpoint Sources..................................................................... 3-4

3.2.1 Private Residential Sewage Treatment ........................................................ 3-4

3.2.2 Biosolids ...................................................................................................... 3-6

3.2.3 Pets............................................................................................................... 3-7

3.2.4 Livestock...................................................................................................... 3-8

3.2.5 Wildlife ...................................................................................................... 3-11

4. MODELING PROCEDURE: LINKING THE SOURCES TO THE ENDPOINT................................................................................................................4-1

4.1 Modeling Framework Selection....................................................................... 4-1

4.2 Model Setup ..................................................................................................... 4-2

4.2.1 Subwatersheds.............................................................................................. 4-2

4.2.2 Land uses ..................................................................................................... 4-4

4.3 Stream Characteristics ..................................................................................... 4-8

4.4 Selection of a TMDL Critical Condition ....................................................... 4-10

4.5 Selection of Representative Modeling Periods .............................................. 4-15

4.6 Source Representation ................................................................................... 4-19


TABLE OF CONTENTS ix

4.6.1 Permitted Sources ...................................................................................... 4-19

4.6.2 Private Residential Sewage Treatment ...................................................... 4-21

4.6.3 Livestock.................................................................................................... 4-22

4.6.4 Biosolids .................................................................................................... 4-24

4.6.5 Wildlife ...................................................................................................... 4-24

4.6.6 Pets............................................................................................................. 4-25

4.7 Sensitivity Analysis ....................................................................................... 4-26

4.7.1 Hydrology Sensitivity Analysis ................................................................. 4-26

4.7.2 Water Quality Parameter Sensitivity Analysis .......................................... 4-29

4.8 Model Calibration and Validation Processes................................................. 4-37

4.8.1 HSPF - Hydrologic Calibration and Validation......................................... 4-37

4.8.2 HSPF – E. coli Water Quality Calibration................................................. 4-44

4.8.3 HSPF – Bacteria Water Quality Validation ............................................... 4-52

5. BACTERIAL ALLOCATION ..................................................................................5-1

5.1 Margin of Safety (MOS).................................................................................. 5-2

5.2 Waste Load Allocations (WLAs)..................................................................... 5-2

5.3 Load Allocations (LAs) ................................................................................... 5-2

5.4 Final Total Maximum Daily Loads (TMDLs) ................................................. 5-3

5.4.1 Upper Powell River (VAS-P17R_POW01A94).......................................... 5-4


5.4.3 Butcher Fork (VAS-P18R_BUH01A04) ................................................... 5-13

5.4.4 North Fork Powell River (VAS-P20R_PWL01A00) ................................ 5-19

5.4.5 Wallen Creek (VAS-P22_WAL01A00) .................................................... 5-24

5.4.6 Middle Powell River (VAS-P19R_POW03A00) ...................................... 5-28

5.4.7 Lower Powell River (VAS-P21R_POW02A02) ....................................... 5-36


x TABLE OF CONTENTS

6. WATER QUALITY ASSESSMENT........................................................................6-1

6.1 Applicable Criterion for Benthic Impairment.................................................. 6-1

6.2 Benthic Assessment – Powell River ................................................................ 6-1

6.2.1 Coal Slurry Spill in the Powell River Basin October 24, 1996 ................. 6-13

6.3 Benthic Assessment – North Fork Powell River ........................................... 6-13

6.4 Benthic Assessment – South Fork Powell River ........................................... 6-19

6.5 Habitat Assessments ...................................................................................... 6-26

6.5.1 Habitat Assessment at Biological Monitoring Stations –Powell River ..... 6-27

6.5.2 Habitat Assessment at Biological Monitoring Stations – North Fork Powell River .................................................................................................................... 6-33

6.5.3 Habitat Assessment at Biological Monitoring Stations – South Fork Powell River .................................................................................................................... 6-36

6.6 Discussion of In-stream Water Quality.......................................................... 6-39

6.6.1 Inventory of Water Quality Monitoring Data ............................................ 6-39

6.7 VADEQ special Upper Powell River PAH monitoring sweep June 2009 .... 6-73

6.8 Endangered and threatened mussels in the Powell River Basin .................... 6-81

7. TMDL ENDPOINT: STRESSOR IDENTIFICATION – POWELL RIVER ...........7-1

7.1 Stressor Identification – Powell River ............................................................. 7-1

7.2 Non-Stressors................................................................................................... 7-3

7.2.1 Low Dissolved Oxygen................................................................................ 7-3

7.2.2 Nutrients....................................................................................................... 7-5

7.2.3 Toxics (ammonia, PCBs and pesticides) ..................................................... 7-9

7.2.4 Metals......................................................................................................... 7-10

7.2.5 Temperature ............................................................................................... 7-10

7.2.6 Field pH ..................................................................................................... 7-13

7.3 Possible Stressors........................................................................................... 7-15


TABLE OF CONTENTS xi

7.3.1 Pesticides (Heptachlor epoxide) ................................................................ 7-15

7.3.2 Sulfate ........................................................................................................ 7-15

7.3.3 Organic matter (Total organic solids, total organic carbon and total kjeldahl nitrogen) ................................................................................................................. 7-18

7.3.4 Conductivity/Total dissolved solids (TDS) ............................................... 7-21

7.3.5 Total PAHs (Polycyclic Aromatic Hydrocarbons) .................................... 7-27

7.4 Most Probable Stressor(s) .............................................................................. 7-37

7.4.1 Sediment .................................................................................................... 7-37

8. TMDL ENDPOINT: STRESSOR IDENTIFICATION – NORTH FORK POWELL RIVER ......................................................................................................8-1

8.1 Stressor Identification – North Fork Powell River .......................................... 8-1

8.2 Non-Stressors................................................................................................... 8-1


8.2.2 Nutrients....................................................................................................... 8-4

8.2.3 Toxics (ammonia, PCBs and pesticides) ..................................................... 8-7

8.2.4 Metals........................................................................................................... 8-8

8.2.5 Temperature ................................................................................................. 8-8

8.2.6 Field pH ..................................................................................................... 8-10

8.2.7 Organic matter ........................................................................................... 8-12


8.3.1 Sulfate ........................................................................................................ 8-15

8.3.2 Conductivity/Total dissolved solids (TDS) ............................................... 8-16

8.3.3 Total PAHs (Polycyclic Aromatic Hydrocarbons) .................................... 8-22

8.4 Most Probable Stressors................................................................................. 8-27

8.4.1 Sediment .................................................................................................... 8-27

9. TMDL ENDPOINT: STRESSOR IDENTIFICATION – SOUTH FORK POWELL RIVER ......................................................................................................9-1


xii TABLE OF CONTENTS

9.1 Stressor Identification – South Fork Powell River .......................................... 9-1

9.2 Non-Stressors................................................................................................... 9-1


9.2.2 Nutrients....................................................................................................... 9-3

9.2.3 Toxics (ammonia, PAHs, PCBs and pesticides).......................................... 9-6

9.2.4 Metals........................................................................................................... 9-6

9.2.5 Temperature ................................................................................................. 9-6

9.2.6 Field pH ....................................................................................................... 9-8

9.2.7 Organic matter ............................................................................................. 9-9

9.2.8 Sulfate ........................................................................................................ 9-12

9.2.9 Conductivity/total dissolved solids (TDS)................................................. 9-13


9.4 Most Probable Stressor(s) .............................................................................. 9-15

9.4.1 Sediment .................................................................................................... 9-15

10. REFERENCE WATERSHED SELECTION ..........................................................10-1

11. MODELING PROCEDURE: LINKING THE SOURCES TO THE ENDPOINT- SEDIMENT.......................................................................................11-1

11.1 Modeling Framework Selection - GWLF...................................................... 11-1

11.2 GWLF Model Setup....................................................................................... 11-2

11.2.1 Sediment Source Assessment ................................................................ 11-3

11.2.2 Sediment Source Representation – Input Requirements........................ 11-4

11.2.3 Selection of Representative Modeling Period - GWLF....................... 11-10

11.3 GWLF Sensitivity Analyses ........................................................................ 11-10

11.4 GWLF Hydrology Calibration..................................................................... 11-12

11.4.1 Powell River – Impaired Stream.......................................................... 11-12

11.4.2 Clinch River – Reference Stream ........................................................ 11-15


TABLE OF CONTENTS xiii

11.5 Sediment Existing Conditions ..................................................................... 11-18

12. SEDIMENT ALLOCATION...................................................................................12-1

12.1 Margin of Safety ............................................................................................ 12-1

12.2 Future Growth Considerations....................................................................... 12-2

12.3 Sediment TMDL ............................................................................................ 12-2

13. TMDL REASONABLE ASSURANCE..................................................................13-1

13.1 Continuing Planning Process and Water Quality Management Planning ..... 13-1

13.2 Staged Implementation .................................................................................. 13-2

13.3 Implementation of Waste Load Allocations .................................................. 13-2

13.3.1 Stormwater............................................................................................. 13-2

13.3.2 TMDL Modifications for New or Expanding Discharges ..................... 13-3

13.4 Implementation of Load Allocations ............................................................. 13-4

13.4.1 Implementation Plan Development........................................................ 13-4

13.4.2 Staged Implementation Scenarios.......................................................... 13-5

13.4.3 Link to Ongoing Restoration Efforts ..................................................... 13-6

13.4.4 Implementation Funding Sources .......................................................... 13-6

13.5 Follow-Up Monitoring................................................................................... 13-7

13.6 Attainability of Designated Uses ................................................................... 13-9

14. PUBLIC PARTICIPATION ....................................................................................14-1

REFERENCES ............................................................................................................... R-1

GLOSSARY ................................................................................................................... G-1

APPENDIX A- CURRENT CONDITIONS FECAL COLIFORM LOADS................. A-1

APPENDIX B- SPECIAL SAMPLING ......................................................................... B-1


LIST OF FIGURES xv

LIST OF FIGURES

Figure 1.1 Location of the Powell River watershed..................................................1-2

Figure 1.2 The impaired segments in the Powell River watershed. ........................1-10

Figure 2.1 Location of VADEQ water quality monitoring stations in the Powell River watershed. ............................................................................................2-4

Figure 2.2 Location of BST water quality monitoring stations in the Powell River watershed. ......................................................................................................2-12

Figure 4.1 All subwatersheds delineated for modeling in the Powell River study area. .................................................................................................................. 4-3

Figure 4.2 Land uses in the Powell River study area watershed...............................4-6

Figure 4.3 Stream profile representation in HSPF. ...................................................4-9

Figure 4.4 Fecal bacteria and E.coli concentrations at 6BPOW138.91 on the Powell River versus discharge at USGS Gaging Station #03531500................4-11

Figure 4.5 Fecal bacteria concentrations at 6BPOW165.78 on the Powell River versus discharge at USGS Gaging Station #03531500..................................4-11



Figure 4.8 Fecal bacteria and E.coli concentrations at 6BPWL001.49 on the N.F. Powell River versus discharge at USGS Station #03531500.....................4-13

Figure 4.9 Fecal bacteria and E.coli concentrations at 6BPWL004.10 on the N.F. Powell River versus discharge at USGS Station #03531500.....................4-13

Figure 4.10 E.coli bacteria concentrations at 6BWAL000.12 on Wallen Creek versus discharge at USGS Gaging Station #03531500. ................................4-14

Figure 4.11 Fecal bacteria concentrations at 6BPLL006.38 on the S.F. Powell River versus discharge at USGS Gaging Station #03531500......................4-14

Figure 4.12 Fecal bacteria concentrations at 6BBUH000.76 on Butcher Fork versus discharge at USGS Gaging Station #03531500............................................4-15

Figure 4.13 Modeling time periods, annual historical flow (USGS Station 03531500), and precipitation (Station 440735/449215) data. .................................4-17

Figure 4.14 Modeling time periods, seasonal historical flow (USGS Station 03531500), and precipitation (Station 440735/449215) data. .................................4-18

Figure 4.15 Example of raccoon habitat layer in the Powell River study area, as developed by MapTech...............................................................................4-25

Figure 4.16 Results of sensitivity analysis on monthly mean concentrations as affected by changes in the in-stream first-order decay rate (FSTDEC). .............4-31


xvi LIST OF FIGURES

Figure 4.17 Results of sensitivity analysis on monthly mean concentrations as affected by changes in maximum fecal accumulation on land (MON-SQOLIM). ................................................................................................................4-32

Figure 4.18 Results of sensitivity analysis on monthly mean concentrations as affected by changes in the wash-off rate from land surfaces (WSQOP).............4-33

Figure 4.19 Results of total loading sensitivity analysis for outlet of the Powell River and Tributaries study area..................................................................4-34

Figure 4.20 Results of sensitivity analysis on monthly geometric-mean concentrations in the Powell River and Tributaries study area, as affected by changes in land-based loadings...........................................................................4-35

Figure 4.21 Results of sensitivity analysis on monthly geometric-mean concentrations in the Powell River and Tributaries study area, as affected by changes in loadings from direct nonpoint sources..............................................4-36

Figure 4.22 Powell River modeled flow duration versus USGS Gaging Station #03531500 data from 10/1/1992 to 9/30/1996 (subwatershed 13)..............4-39

Figure 4.23 Powell River modeled results versus USGS Gaging Station #03531500 data from 10/1/1992 to 9/30/1996 (subwatershed 13). .........................4-40

Figure 4.24 Powell River modeled flow duration versus USGS Gaging Station #03531500 data for validation (subwatershed 13). .....................................4-42

Figure 4.25 Powell River validation modeled results versus USGS Gaging Station #03531500 data from (subwatershed 13). ...................................................4-43

Figure 4.26 Fecal coliform calibration for 10/1/2000 to 9/30/2003 for VADEQ station 6BPOW193.38 in subwatershed 2 on the Powell River................4-46



Figure 4.29 Fecal coliform calibration for 10/1/2000 to 9/30/2003 for VADEQ station 6BPOW138.91 in subwatershed 14 on the Powell River..............4-47

Figure 4.30 Fecal coliform calibration for 10/1/2000 to 9/30/2003 for VADEQ station 6BBUH000.76 in subwatershed 34 on Butcher Fork....................4-48

Figure 4.31 Fecal coliform calibration for 10/1/2001 to 9/30/2003 for VADEQ station 6BPLL004.24 in subwatershed 30 on S.F. Powell River..............4-48

Figure 4.32 Fecal coliform calibration for 10/1/2001 to 9/30/2003 for VADEQ station 6BPLL000.27 in subwatershed 31 on S.F. Powell River..............4-49

Figure 4.33 Fecal coliform calibration for 10/1/1997 to 9/30/2000 for VADEQ station 6BPWL001.49 in subwatershed 55 on N.F. Powell River............4-49

Figure 4.34 E. coli calibration for 10/1/2002 to 9/30/2004 for VADEQ station 6BWAL000.12 in subwatershed 24 on Wallen Creek. ................................4-50


LIST OF FIGURES xvii

Figure 4.35 E. coli validation for 10/1/12006 to 9/30/2008 for VADEQ station 6BPOW193.38 in subwatershed 2 on the Powell River...............................4-53

Figure 4.36 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ station 6BPOW179.20 in subwatershed 5 on the Powell River................4-53

Figure 4.37 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ station 6BPOW165.78 in subwatershed 9 on the Powell River................4-54

Figure 4.38 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ station 6BPOW138.91 in subwatershed 14 on the Powell River..............4-54

Figure 4.39 E.coli validation for 10/1/2006 to 9/30/2008 for VADEQ station 6BBUH000.76 in subwatershed 34 on Butcher Fork...................................4-55

Figure 4.40 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ station 6BPLL006.38 in subwatershed 29 on S.F. Powell River..............4-55

Figure 4.41 E.coli validation for 10/1/2006 to 9/30/2008 for VADEQ station 6BPLL004.24 in subwatershed 30 on S.F. Powell River.............................4-56

Figure 4.42 E.coli validation for 10/1/2006 to 9/30/2008 for VADEQ station 6BPLL000.76 in subwatershed 34 on S.F. Powell River.............................4-56

Figure 4.43 E.coli validation for 10/1/2002 to 9/30/2005 for VADEQ station 6BPWL006.59 in subwatershed 50 on N.F. Powell River...........................4-57

Figure 4.44 E.coli validation for 10/1/2004 to 9/30/2005 for VADEQ station 6BWAL000.12 in subwatershed 24 on N.F. Powell River. .........................4-57

Figure 5.1 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 5, Upper Powell River impairment outlet. ..................................................................................................................5-6

Figure 5.2 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 29, S.F. Powell River impairment outlet. ................................................................................................................5-11

Figure 5.3 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 34, Butcher Fork impairment outlet...............5-16

Figure 5.4 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 56, N.F. Powell River impairment outlet. ................................................................................................................5-21

Figure 5.5 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 24, Wallen Creek impairment outlet..............5-26

Figure 5.6 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 10, Middle Powell River impairment outlet. ................................................................................................................5-31

Figure 5.7 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 14, Lower Powell River impairment outlet. ................................................................................................................5-38


xviii LIST OF FIGURES

Figure 6.1 Biological, special study and ambient water quality monitoring stations on the Powell River. .....................................................................................6-3

Figure 6.2 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPOW120.12 on the Powell River............................................6-5





Figure 6.7 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPOW179.20 on the Powell River..........................................6-10



Figure 6.10 Biological, special study and ambient water quality monitoring stations on the North Fork Powell River..................................................................6-14

Figure 6.11 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPWL000.06 on the North Fork Powell River. ......................6-15

Figure 6.12 VASCI biological monitoring scores for VADEQ benthic monitoring station 6PWL001.93 on the North Fork Powell River..........................6-16



Figure 6.15 Biological and ambient water quality monitoring stations on the South Fork Powell River..........................................................................................6-20

Figure 6.16 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL000.17 on the South Fork Powell River.........................6-21

Figure 6.17 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL001.61 on the South Fork Powell River.........................6-22

Figure 6.18 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL002.55 on South Fork Powell River. .............................6-24



LIST OF FIGURES xix


Figure 6.21 Upper Powell River VADEQ monitoring stations June 2009. ..............6-75

Figure 6.22 Lower Powell River VADEQ monitoring station June 2009. ...............6-76

Figure 6.23 Ely Creek restoration site, photo by the USACOE................................6-83

Figure 6.24 Average total iron and total aluminum concentrations before and after reclamation................................................................................................6-84

Figure 6.25 Average field pH measurements before and after reclamation..............6-84

Figure 6.26 Average conductivity measurements before and after reclamation...............................................................................................................6-85

Figure 6.27 Lick Branch restoration site in 2007, photo by USACOE.....................6-86

Figure 7.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPOW138.91. ..........................................................................................................7-4



Figure 7.4 Total phosphorus concentrations at VADEQ station 6BPOW138.91. ..........................................................................................................7-6



Figure 7.7 Nitrate-nitrogen concentrations at VADEQ station 6BPOW138.91. ..........................................................................................................7-7



Figure 7.10 Ammonia-nitrogen concentrations at VADEQ station 6BPOW165.78. ..........................................................................................................7-9

Figure 7.11 Ammonia-nitrogen concentrations at VADEQ station 6BPOW179.20. ........................................................................................................7-10

Figure 7.12 Temperature measurements at VADEQ station 6BPOW138.91. ..........7-11



Figure 7.15 Field pH measurements at VADEQ station 6BPOW138.91. ................7-13


xx LIST OF FIGURES

Figure 7.16 Field pH measurements at VADEQ station 6BPOW165.78 .................7-14

Figure 7.17 Field pH measurements at VADEQ station 6BPOW179.20. ................7-14

Figure 7.18 Sulfate concentrations at VADEQ monitoring station 6BPOW138.91. ........................................................................................................7-16



Figure 7.21 Total organic solids concentrations at VADEQ monitoring station 6BPOW138.91. ............................................................................................7-18



Figure 7.24 Total organic carbon concentrations at VADEQ monitoring station 6BPOW138.91. ............................................................................................7-20

Figure 7.25 The relationship between %Ephemeroptera and conductivity from reference and mined sites (Pond, 2004). .........................................................7-21

Figure 7.26 Conductivity measurements at VADEQ station 6BPOW138.91...........7-22



Figure 7.29 TDS concentrations at VADEQ station 6BPOW138.91........................7-25

Figure 7.30 TDS concentrations at 6BPOW165.78. .................................................7-25

Figure 7.31 TDS concentrations at 6BPOW179.20. .................................................7-26

Figure 7.32 Naphthalene concentrations in bottom sediment in Virginia.................7-29

Figure 7.33 TSS concentrations at VADEQ station 6BPOW138.91. .......................7-38



Figure 8.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPWL001.49. ..........................................................................................................8-2



Figure 8.4 Total phosphorus concentrations at VADEQ station 6BPWL001.49. ..........................................................................................................8-4


LIST OF FIGURES xxi

Figure 8.5 Total phosphorus concentrations at VADEQ station 6BPWL004.10. ..........................................................................................................8-5

Figure 8.6 Nitrate-nitrogen concentrations at VADEQ station 6BPWL001.49. ..........................................................................................................8-5



Figure 8.9 Ammonia-nitrogen concentrations at VADEQ station 6BPWL001.49. ..........................................................................................................8-7

Figure 8.10 Temperature measurements at VADEQ station 6BPWL001.49..............8-9

Figure 8.11 Temperature measurements at VADEQ station 6BPWL004.10..............8-9

Figure 8.12 Temperature measurements at VADEQ station 6BPWL006.59............8-10

Figure 8.13 Field pH measurements at VADEQ station 6BPWL001.49..................8-11



Figure 8.16 Total organic solids concentrations at VADEQ monitoring station 6BPWL001.49..............................................................................................8-13

Figure 8.17 Total organic carbon concentrations at VADEQ monitoring station 6BPWL001.49..............................................................................................8-13

Figure 8.18 Chemical oxygen demand concentrations at VADEQ monitoring station 6BPWL001.49. ..........................................................................8-14

Figure 8.19 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPWL001.49..............................................................................................8-14

Figure 8.20 Sulfate concentrations at VADEQ monitoring station 6BPWL001.49. ........................................................................................................8-16

Figure 8.21 The relationship between %Ephemeroptera and conductivity from reference and mined sites (Pond, 2004). .........................................................8-17

Figure 8.22 Conductivity measurements at VADEQ station 6BPWL001.49. ..........8-18



Figure 8.25 TDS concentrations at VADEQ station 6BPWL001.49. .......................8-20

Figure 8.26 TDS concentrations at 6BPWL004.10...................................................8-20

Figure 8.27 Naphthalene concentrations in bottom sediment in Virginia.................8-24

Figure 8.28 TSS concentrations at VADEQ station 6BPPWL001.49. .....................8-28


xxii LIST OF FIGURES

Figure 9.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPLL004.24.............................................................................................................9-2

Figure 9.2 Dissolved oxygen concentrations at VADEQ monitoring station 6BPLL006.38.............................................................................................................9-3

Figure 9.3 Total phosphorus concentrations at VADEQ station 6BPLL004.24.............................................................................................................9-4

Figure 9.4 Total phosphorus concentrations at VADEQ station 6BPLL006.38.............................................................................................................9-4

Figure 9.5 Nitrate-nitrogen concentrations at VADEQ station 6BPLL004.24.............................................................................................................9-5

Figure 9.6 Nitrate-nitrogen concentrations at VADEQ station 6BPLL006.38.............................................................................................................9-5

Figure 9.7 Temperature measurements at VADEQ station 6BPLL004.24...............9-7

Figure 9.8 Temperature measurements at VADEQ station 6BPLL006.38...............9-7

Figure 9.9 Field pH measurements at VADEQ station 6BPLL004.24. ....................9-8

Figure 9.10 Field pH measurements at VADEQ station 6BPLL006.38 .....................9-9

Figure 9.11 Total organic solids concentrations at VADEQ monitoring station 6BPLL004.24. ..............................................................................................9-10

Figure 9.12 Total organic solids concentrations at VADEQ monitoring station 6BPLL006.38. ..............................................................................................9-10

Figure 9.13 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPLL004.24. ..............................................................................................9-11

Figure 9.14 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPLL006.38. ..............................................................................................9-11

Figure 9.15 Sulfate concentrations at VADEQ monitoring station 6BPLL006.38...........................................................................................................9-12

Figure 9.16 Conductivity measurements at VADEQ monitoring station 6BPLL004.24...........................................................................................................9-13

Figure 9.17 Conductivity measurements at VADEQ monitoring station 6BPLL004.24...........................................................................................................9-14

Figure 9.18 Total dissolved solids concentrations at VADEQ monitoring station 6BPLL004.24. ..............................................................................................9-14

Figure 9.19 Total dissolved solids concentrations at VADEQ monitoring station 6BPLL006.38. ..............................................................................................9-15

Figure 9.20 Total suspended solids concentrations at VADEQ monitoring station 6BPLL004.24. ..............................................................................................9-16

Figure 9.21 Total suspended solids concentrations at VADEQ monitoring station 6BPLL006.38. ..............................................................................................9-16


LIST OF FIGURES xxiii

Figure 10.1 Location of the impaired and reference watersheds. .............................10-2

Figure 11.1 Comparison of monthly GWLF simulated (Modeled) and monthly USGS (Observed) streamflow in Powell River.......................................11-13

Figure 11.2 Comparison of cumulative monthly GWLF simulated (Modeled) and cumulative USGS (Observed) streamflow in Powell River..........11-14

Figure 11.3 Comparison of monthly GWLF simulated (Modeled) and monthly USGS (Observed) streamflow in Clinch River. ......................................11-16

Figure 11.4 Comparison of cumulative monthly GWLF simulated (Modeled) and cumulative USGS (Observed) streamflow in Clinch River. .........11-17


LIST OF TABLES xxv

LIST OF TABLES

Table ES.1 Impairments within the Powell River watershed included in this study.....................................................................................................................xxxviii

Table ES.2 Bacteria calibration periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area. ......................................... xli

Table ES.3 Bacteria validation periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area. .......................................... xli

Table ES.4 Average annual in-stream cumulative pollutant loads modeled after allocation in the Powell River impairments. ....................................................xliii

Table 1.1 Impairments within the Powell River watershed included in this study. ....................................................................................................................1-11

Table 2.1 Summary of fecal coliform (cfu/100mL) data collected by VADEQ from January 1980 – December 2009.........................................................2-5

Table 2.2 Summary of E. coli (cfu/100mL) data collected by VADEQ from May 2002 – December 2009......................................................................................2-6

Table 2.3 Summary of bacterial source tracking results from water samples collected at the Powell River station (6BPOW179.20). ............................................2-9

Table 2.4 Summary of bacterial source tracking results from water samples collected at the Powell River station (6BPOW180.62). ............................................2-9

Table 2.5 Summary of bacterial source tracking results from water samples collected at the North Fork Powell River station (6BPWL001.49). ........................2-10

Table 2.6 Summary of bacterial source tracking results from water samples collected at the South Fork Powell River station (6BPLL006.38). .........................2-10

Table 2.7 Summary of bacterial source tracking results from water samples collected at the Butcher Fork station (6BBUH000.76)............................................2-11

Table 3.1 Summary of VPDES permitted point sources permitted for fecal coliform (FC) control in the Powell River study area................................................3-2

Table 3.2 Single family home permits in the Powell River study area........................3-3

Table 3.3 Human population, housing units, houses on sanitary sewer, septic systems, and other sewage disposal systems for areas contributing to impaired segments in the Powell River study area. ...................................................3-6

Table 3.4 Application of biosolids within the Powell River study area (2000 – 2008). 3-7

Table 3.5 Domestic animal population density, waste load, and fecal coliform density. ........................................................................................................3-7

Table 3.6 Estimated domestic animal populations in areas contributing to impaired segments in the Powell River study area. ...................................................3-8


xxvi LIST OF TABLES

Table 3.7 Livestock populations in areas contributing to impaired segments in the Powell River study area. ..................................................................................3-9

Table 3.8 Average fecal coliform densities and waste loads associated with livestock. ....................................................................................................................3-9

Table 3.9 Average percentage of collected livestock waste applied throughout year. ....................................................................................................... 3-10

Table 3.10 Average time dry cows and replacement heifers spend in different areas per day..............................................................................................3-11

Table 3.11 Average time beef cows not confined in feedlots spend in pasture and stream access areas per day. .................................................................3-11

Table 3.12 Wildlife population densities for the Powell River study area. .............3-12

Table 3.13 Estimated wildlife populations in the Powell River study area. ............3-12

Table 3.14 Average fecal coliform densities and percentage of time spent in stream access areas for wildlife. ..............................................................................3-13

Table 3.15 Wildlife fecal production rates and habitat. ...........................................3-14

Table 4.1 Impairments and subwatersheds within the Powell River study area. ......................................................................................................................4-4

Table 4.2 Consolidated land use categories for the Powell River drainage area used in HSPF modeling......................................................................................4-5

Table 4.3 Spatial distribution of land use types in acres in the Powell River study area. ..................................................................................................................4-7

Table 4.4 Summary of Manning's roughness coefficients for channel cells*..............4-9

Table 4.5 Example of an F-table calculated for the HSPF model..............................4-10

Table 4.6 Comparison of modeled period to historical records for the Powell River.........................................................................................................................4-18

Table 4.7 Flow rates and bacteria loads used to model VADEQ active permits in the Powell River study area. ...................................................................4-20

Table 4.8 Estimated failing septic systems and pit privies for 2008 in the Powell River study area. ..........................................................................................4-21

Table 4.9 HSPF base parameter values used to determine hydrologic model response....................................................................................................................4-27

Table 4.10 HSPF Sensitivity analysis results for hydrologic model parameters for the Powell River and Tributaries. ....................................................4-28

Table 4.11 Base parameter values used to determine water quality model response. ................................................................................................................4-29

Table 4.12 Percent change in average monthly fecal coliform mean for the years 1993-1996.......................................................................................................4-30


LIST OF TABLES xxvii

Table 4.13 Initial hydrologic parameters estimated for the Powell River TMDL study area, and resulting final values after calibration. ...............................4-38

Table 4.14 Hydrology calibration model performance from 10/1/1992 through 9/30/1996 at USGS Gaging Station #03531500 on the Powell River and Tributaries (subwatershed 13).................................................................4-38

Table 4.15 Hydrology validation model performance from 10/1/1996 through 9/30/2000 at USGS Gaging Station #03531500 on the Powell River (subwatershed 13). .........................................................................................4-41

Table 4.16 Model parameters utilized for water quality calibration........................4-45

Table 4.17 Bacteria calibration periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area. .......................................4-45

Table 4.18 Monitored and simulated maximum value, geometric mean, and single sample violation percentage for the calibration period. ................................4-51

Table 4.19 Bacteria validation periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area. ......................................4-52

Table 4.20 Monitored and simulated maximum value, geometric mean, and single sample violation percentage for the validation period. .................................4-58

Table 5.1 Allocation scenarios for reducing current bacteria loads in Upper Powell River (VAS-P17R_POW01A94) (subwatershed 1, 2, 3, 4, 5, 35, 36, 37, 44, 45, and Callahan Creek).................................................................................5-5

Table 5.2 Estimated existing and allocated E. coli in-stream loads in the Upper Powell River impairment. ...............................................................................5-7

Table 5.3 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Upper Powell River impairment. .................5-8

Table 5.4 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in the Upper Powell River impairment. .................5-9

Table 5.5 Allocation scenarios for reducing current bacteria loads in S.F. Powell River (subwatershed 27, 28, 29). .................................................................5-10

Table 5.6 Estimated existing and allocated E. coli in-stream loads in the S.F. Powell River impairment. ........................................................................................5-12

Table 5.7 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the S.F. Powell River impairment. ..................5-13

Table 5.8 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in the S.F. Powell River impairment. ..................5-13

Table 5.9 Allocation scenarios for reducing current bacteria loads in Butcher Fork (subwatershed 33,34).......................................................................................5-15

Table 5.10 Estimated existing and allocated E. coli in-stream loads in Butcher Fork impairment.........................................................................................5-17


xxviii LIST OF TABLES

Table 5.11 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in Butcher Fork impairment.................................5-18

Table 5.12 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Butcher Fork impairment.................................5-19

Table 5.13 Allocation scenarios for reducing current bacteria loads in N.F. Powell River (subwatershed 46, 47, 48, 49, 50, 55, 56, 58, 59, and Straight Creek). ................................................................................................................5-20

Table 5.14 Estimated existing and allocated E. coli in-stream loads in the N.F. Powell River impairment. ................................................................................5-22

Table 5.15 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the N.F. Powell River impairment...................5-23

Table 5.16 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in N.F. Powell River impairment.........................5-23

Table 5.17 Allocation scenarios for reducing current bacteria loads in Wallen Creek (subwatershed 18,19,21,23,24,25). ...................................................5-25

Table 5.18 Estimated existing and allocated E. coli in-stream loads in Wallen Creek impairment. .......................................................................................5-27

Table 5.19 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in Wallen Creek impairment................................5-28

Table 5.20 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Wallen Creek impairment................................5-28

Table 5.21 Allocation scenarios for reducing current bacteria loads in Middle Powell River (subwatershed 6,7,8,9,10,30,31,32,69,Upper Powell River, S.F. Powell River, and Butcher Fork impairments). .....................................5-30

Table 5.22 Estimated existing and allocated E. coli in-stream loads in the Middle Powell River impairment.............................................................................5-32

Table 5.23 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Middle Powell River impairment. .............5-33

Table 5.24 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Middle Powell River impairment. ...................5-35

Table 5.25 Allocation scenarios for reducing current bacteria loads in Lower Powell River (subwatershed 11,12,13,14,26 and the Middle Powell River impairment). ...................................................................................................5-37

Table 5.26 Estimated existing and allocated E. coli in-stream loads in the Lower Powell River impairment..............................................................................5-39

Table 5.27 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Lower Powell River impairment. ..............5-40

Table 5.28 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Lower Powell River impairment. ....................5-42


LIST OF TABLES xxix

Table 6.1 Components of the VASCI. .........................................................................6-1

Table 6.2 VADEQ monitoring stations on the Powell River.......................................6-2

Table 6.3 VASCI biological monitoring data for station 6BPOW120.12 on the Powell River.........................................................................................................6-4





Table 6.8 VASCI biological monitoring data for station 6BPOW179.20 on the Powell River.......................................................................................................6-10

Table 6.9 VASCI biological monitoring data for station 6BPOW180.72 on the Powell River.......................................................................................................6-11

Table 6.10 VASCI biological monitoring data for station 6BPOW184.19 on the Powell River..................................................................................................6-12

Table 6.11 VASCI biological monitoring data for two VADEQ benthic monitoring stations on the Powell River, November 7, 1996..................................6-13

Table 6.12 Benthic, ambient and special study monitoring stations on the North Fork Powell River..........................................................................................6-14

Table 6.13 VASCI biological monitoring data for station 6BPWL000.06 on the North Fork Powell River....................................................................................6-15

Table 6.14 VASCI biological monitoring data for station 6BPWL001.93 on the North Fork Powell River....................................................................................6-16

Table 6.15 VASCI data for VADEQ station 6BPWL004.40 on the North Fork Powell River. ...................................................................................................6-17

Table 6.16 VASCI data for VADEQ station 6BPWL006.16 on the North Fork Powell River. ...................................................................................................6-18

Table 6.17 Benthic and ambient monitoring stations on the South Fork Powell River.............................................................................................................6-19

Table 6.18 VASCI data for VADEQ station 6BPLL000.17 on the South Fork Powell River. ...................................................................................................6-21




xxx LIST OF TABLES



Table 6.23 Classification of habitat metrics based on score. ...................................6-27

Table 6.24 Habitat scores for VADEQ monitoring station 6BPOW120.12 on the Powell River..................................................................................................6-28









Table 6.33 Habitat scores at VADEQ benthic monitoring station 6BPWL000.06 on the North Fork Powell River......................................................6-34




Table 6.37 Habitat scores at VADEQ benthic monitoring station 6BPLL000.17 on the South Fork Powell River. ......................................................6-36




LIST OF TABLES xxxi



Table 6.42 VADEQ ambient monitoring stations on the Powell River...................6-40

Table 6.43 In-stream water quality data at 6BPOW138.91 in Powell River (3/1995 – 04/2008)...................................................................................................6-40



Table 6.46 VADEQ ambient monitoring stations on the North Fork Powell River. ................................................................................................................6-43

Table 6.47 In-stream water quality data at 6BPWL001.49 on the North Fork Powell River (1/1990 – 12/2006). ...................................................................6-44

Table 6.48 In-stream water quality data at 6BPWL004.10 on the North Fork Powell River (07/2003 – 01/2006). .................................................................6-45

Table 6.49 In-stream water quality data at 6BPWL006.59 on the North Fork Powell River (08/2003 – 06/2005). .................................................................6-45

Table 6.50 VADEQ ambient monitoring stations on the South Fork Powell River. ................................................................................................................6-46

Table 6.51 In-stream water quality data at 6BPLL000.27 on the South Fork Powell River (08/2001 – 12/2007)...........................................................................6-46



Table 6.54 Sediment metal sampling results from four VADEQ fish tissue monitoring stations on the Powell River..................................................................6-49

Table 6.55 Sediment polycyclic aromatic hydrocarbons (PAHs) results from four VADEQ fish tissue monitoring stations on the Powell River. ................6-50

Table 6.56 Sediment polychlorinated biphenyls (PCBs) and pesticide results from VADEQ fish tissue monitoring stations on the Powell River. ............6-51

Table 6.57 Special study sediment metals results from VADEQ ambient monitoring station 6BPOW138.91 on the Powell River..........................................6-51



xxxii LIST OF TABLES


Table 6.60 Sediment metals results from four VADEQ special study monitoring stations on the Powell River..................................................................6-54

Table 6.61 Sediment metals results from VADEQ special study monitoring station 6BPOW143.53 on the Powell River. ...........................................................6-54

Table 6.62 Sediment metals results from four VADEQ special study monitoring stations on the Powell River..................................................................6-54

Table 6.63 Special study sediment organics results from twoVADEQ ambient monitoring stations on the Powell River....................................................6-55

Table 6.64 Special study sediment organics results from four VADEQ special study monitoring stations on the Powell River............................................6-58

Table 6.65 Summary of sediment organic compounds that exceeded screening values at VADEQ Powell River monitoring stations. .............................6-59

Table 6.66 Dissolved metal concentrations at two VADEQ ambient monitoring stations on the Powell River..................................................................6-60

Table 6.67 Dissolved metal concentrations at two VADEQ special study monitoring stations on the Powell River..................................................................6-60

Table 6.68 Dissolved metal concentrations at VADEQ special study monitoring station 6BPOW133.00 on the Powell River..........................................6-61

Table 6.69 Dissolved metal concentrations at three VADEQ special study monitoring stations on the Powell River..................................................................6-61

Table 6.70 Special study sediment metal sampling results at VADEQ fish tissue monitoring stations on the North Fork Powell River.....................................6-62

Table 6.71 Special study PCB and pesticide results at VADEQ fish tissue monitoring stations on the North Fork Powell River...............................................6-63

Table 6.72 Special study PAH results at VADEQ fish tissue monitoring stations on the North Fork Powell River..................................................................6-64

Table 6.73 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River. ................................................................................................................6-65

Table 6.74 Special study sediment organics results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River (01/26/2006).............................................................................................................6-67

Table 6.75 Special study sediment organics results at VADEQ ambient monitoring station 6BPWL004.10 on the North Fork Powell River (01/26/2006).............................................................................................................6-70

Table 6.76 Summary of sediment organic compounds that exceeded screening values at VADEQ North Fork Powell River monitoring stations. ..........6-72


LIST OF TABLES xxxiii

Table 6.77 Dissolved metal concentrations at two VADEQ ambient monitoring stations on the North Fork Powell River...............................................6-72

Table 6.78 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPLL006.38 on the South Fork Powell River...........6-73

Table 6.79 Special study PAH monitoring sweep sampling sites June 1-3, 2009 ................................................................................................................6-76

Table 6.80 Special study sediment PAH results at VADEQ ambient monitoring stations in the Powell River Basin June 1-3, 2009................................6-77

Table 6.81 Sediment PAHs hazard quotient* in sweep of Powell River watershed, June 1-3, 2009........................................................................................6-79

Table 6.82 Sediment total organic carbon and particle size in sweep of Powell River watershed, June 1-3, 2009..................................................................6-81

Table 6.83 Endangered and threatened mussels in the Powell River Basin. ...........6-82

Table 7.1 Non-Stressors in the Powell River...............................................................7-3

Table 7.2 Possible Stressors in the Powell River.......................................................7-15

Table 7.3 Ratios of PAH isomers from various sources and the Powell River watershed sediments ................................................................................................7-31

Table 7.4 Sediment PAHs hazard quotients* in the Powell River watershed. ..........7-33

Table 7.5 Probable stressor(s) in the Powell River....................................................7-37

Table 7.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the Powell River......................................7-39

Table 8.1 Non-Stressors in the North Fork Powell River. ...........................................8-1

Table 8.2 Possible Stressors in the North Fork Powell River.................................... 8-15

Table 8.3 Ratios of PAH isomers from various sources and the North Fork Powell River watershed sediments ..........................................................................8-25

Table 8.4 Sediment PAHs hazard quotient* in the North Fork Powell River on. ....................................................................................................................8-27

Table 8.5 Probable stressors in the North Fork Powell River....................................8-27

Table 8.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the North Fork Powell River. ..................8-29

Table 9.1 Non-Stressors in the South Fork Powell River. ...........................................9-1

Table 9.2 Probable stressors in the South ForkPowell River.....................................9-15

Table 9.3 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the South Fork Powell River. ..................9-17

Table 10.1 Powell and Clinch Rivers land use comparison.....................................10-3


xxxiv LIST OF TABLES

Table 11.1 Land use areas used in the GWLF model for the Powell River and Tributaries and area-adjusted Clinch River watersheds....................................11-5

Table 11.2 Permitted Sources in the Powell River watershed excluding the Straight Creek and Callahan Creek areas.................................................................11-9

Table 11.3 Base parameter values used in GWLF sensitivity analysis. ................11-11

Table 11.4 Sensitivity of GWLF model response to changes in selected parameters for Powell River. .................................................................................11-12

Table 11.5 GWLF flow calibration statistics for Powell River. ............................11-12

Table 11.6 GWLF flow calibration statistics for Clinch River..............................11-15

Table 11.7 GWLF watershed parameters in the calibrated impaired and reference watersheds..............................................................................................11-18

Table 11.8 Calibrated GWLF monthly evaporation cover coefficients.................11-18

Table 11.9 The GWLF curve numbers and KLSCP values for existing conditions in the Powell River and Clinch River watersheds................................11-19

Table 11.10 Existing sediment loads for Powell River and area-adjusted Clinch River watersheds. .......................................................................................11-20

Table 12.1 Final TMDL allocation scenario for the impaired Powell River watershed. ................................................................................................................12-3

Table 12.2 Existing and allocated annual sediment loads for DMME mining permits within the Powell River watershed.................................................12-4

Table 12.3 Required sediment reductions for Powell River and Tributaries...........12-5

Table 12.4 Average annual sediment TMDL for Powell River. ..............................12-5

Table 12.5 Maximum daily sediment loads (t/day) for Powell River......................12-8

Table 14.1 Public participation during TMDL development for the Powell River and Tributaries study area. .............................................................................14-1

Table A.1 Current conditions of land applied fecal coliform load for POW01A94 by land use (Sub-watersheds 1, 2, 3, 4, 5, 35, 36, 37, 44, 45): ............ A-2

Table A.2 Monthly, directly deposited fecal coliform loads in each reach of POW01A94 (Reaches 1, 2, 3, 4, 5, 35, 36, 37, 44, 45). ....................................... A-3

Table A.3 Existing annual loads from direct-deposition sources for the POW01A94 (Reaches 1, 2, 3, 4, 5, 35, 36, 37, 44, 45):............................................ A-5

Table A.4 Current conditions of land applied fecal coliform load for PLL02A00 by land use(Sub-watersheds 27, 28, 29): ............................................... A-6

Table A.5 Monthly, directly deposited fecal coliform loads in each reach of PLL02A00 (Reaches 27, 28, 29)............................................................................... A-6

Table A.6 Existing annual loads from direct-deposition sources for the PLL02A00 (Reaches 27, 28, 29): ............................................................................. A-7


LIST OF TABLES xxxv

Table A.7 Current conditions of land applied fecal coliform load for BUH01A04 by land use (Sub-watersheds 33, 34). ................................................... A-8

Table A.8 Monthly, directly deposited fecal coliform loads in each reach of BUH01A04 (Reaches 33, 34)............................................................................... A-8

Table A.9 Existing annual loads from direct-deposition sources for the BUH01A04 (Reaches 33, 34): .................................................................................. A-9

Table A.10 Current conditions of land applied fecal coliform load for PWL01A00 by land-use(Sub-watersheds 46, 47, 48, 49, 50, 55, 56, 58, 59):........ A-10

Table A.11 Monthly, directly deposited fecal coliform loads in each reach of PWL01A00 (Reaches 46, 47, 48, 49, 50, 55, 56, 58, 59)................................... A-11

Table A.12 Existing annual loads from direct-deposition sources for the PWL01A00 (Reaches 46, 47, 48, 49, 50, 55, 56, 58, 59): ...................................... A-13

Table A.13 Current conditions of land applied fecal coliform load for WAL01A00 by land-use(Sub-watersheds 18, 19, 21, 23, 24, 25):......................... A-14

Table A.14 Monthly, directly deposited fecal coliform loads in each reach of WAL01A00 (Reaches 18, 19, 21, 23, 24, 25). ................................................... A-15

Table A.15 Existing annual loads from direct-deposition sources for the WAL01A00 (Reaches 18, 19, 21, 23, 24, 25): ....................................................... A-16

Table A.16 Current conditions of land applied fecal coliform load for POW03A00 by land use(Sub-watersheds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69): ........................................................ A-17

Table A.17 Monthly, directly deposited fecal coliform loads in each reach of POW03A00 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69). ................................................................................ A-18

Table A.18 Existing annual loads from direct-deposition sources for the POW03A00 (Reaches 1, 2 , 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69): ...................................................................................... A-22

Table A.19 Current conditions of land applied fecal coliform load for POW02A02 by land use (Sub-watersheds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69): ........................................................ A-23

Table A.20 Monthly, directly deposited fecal coliform loads in each reach of POW02A02 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69). ................................................................................ A-24

Table A.21 Existing annual loads from direct-deposition sources for the POW02A02 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69): .......................................................................... A-31

Table B. 1 Sediment metals at VADEQ monitoring station 6BBLK000.13. ........... B-1


xxxvi LIST OF TABLES

Table B. 2 Sediment metals at VADEQ monitoring station 6BLOC001.05. ........... B-1

Table B. 3 Sediment metals at VADEQ monitoring station 6BPOW183.55. .......... B-2

Table B. 4 Sediment metals at VADEQ monitoring station 6BPOW197.21. .......... B-2

Table B. 5 Conventional parameters collected at 11 VADEQ monitoring stations in the Powell River watershed on June 1-3, 2009). ..................................... B-3


EXECUTIVE SUMMARY xxxvii

EXECUTIVE SUMMARY

Background and Applicable Standards

Several segments within the Powell River drainage area were impaired. The impairments

in this report fall within two categories, bacteria and general standard impairments.

There are seven stream segments impaired for bacteria violations of the

recreational/swimming standard. Three of the segments are located on the main stem of

the Powell River. The four other segments are one on each of the North Fork Powell

River, the South Fork Powell River, Butcher Fork, and Wallen Creek.

The current study deals with six benthic (general standard) impairments. Three of the six

impairments are along the main stem of the Powell River. There are two benthic

impairments on the South Fork Powell River and one on the North Fork Powell River.

Table ES.1 below shows the details of these impairments.

For the General Standard violations, a process called stressor analysis is conducted to

determine the likely cause of the impairment. The results of this process for the Powell

River and Tributaries benthic impairments determined that sediment was the most

probable stressor.

In Virginia, once a water body violates a given standard, a Total Maximum Daily Load

(TMDL) must be developed. The TMDL is a pollution budget that determines the

amount of pollutant the water body can receive in a given period of time and still meet

the intended standard.

TMD

L Developm

ent

Powell River and Tributaries, VA

xxxviii

EXEC

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Table ES.1 Impairments within the Powell River watershed included in this study.

Stream Name Impairment ID

Impairment(s) Contracted

Initial Listing Year

2006 River Miles

Listing year Violations1/

Total Samples

2006 Listing Violations2/

Total SamplesImpairment Location Description

Butcher Fork VAS-P18R_BUH01A04 E. coli 2004 4.86 4/8 5/12 FC Headwaters to South Fork Powell River conf.

South Fork Powell River VAS-P18R_PLL02A00 E. coli 2004 6.33 6/18 6/18 FC Big Cherry Reservoir to Beaverdam Creek

South Fork Powell River VAS-P18R_PLL01A02 Benthic 1998 1.90 NA NA Beaverdam Creek to Butcher Fork

South Fork Powell River VAS-P18R_PLL01A98 Benthic 1998 3.71 NA NA Butcher Fork to the Powell River

North Fork Powell River VAS-P20R_PWL01A00 Benthic, E. coli 1996, 2004 6.02 4/18 8/20 FC

2/12 E. coli Straight Creek conf. to Powell River conf.

Wallen Creek VAS-P22_WAL01A00 E. coli 2006 2.03 2/8 2/8 Lone Branch to Powell River

Powell River VAS-P17R_POW01A94 Benthic, E. coli 1996, 1996 2.62 NA 14/36 FC

4/11 E. coli Roaring Branch conf. to Dakota St. in Big Stone Gap, VA

Powell River VAS-P19R_POW03A00 Benthic, E. coli 2004, 2004 6.37 5/46 3/25 FC Poor Valley Creek conf. to Public Water Supply

Powell River VAS-P21R_POW02A02 E. coli 2006 12.69 3/19 3/19 E. coli Station Creek conf. to Town Branch conf.

Powell River VAS-P23R_POW02A00 Benthic 2002 8.43 NA NA Hardy Creek conf. to Yellow Creek conf.

FC = Fecal Coliform 1 Based on the interim instantaneous fecal coliform standard of 400 cfu/100mL for samples collected during the assessment period. 2 Based on the instantaneous fecal coliform standard of 400 cfu/100mL and/or the instantaneous E. coli standard of 235 cfu/100mL for samples collected during the assessment period


EXECUTIVE SUMMARY xxxix

TMDL Endpoint and Water Quality Assessment

Fecal bacteria TMDLs in the Commonwealth of Virginia are developed using the E. coli

standard. For this TMDL development, the in-stream E. coli target was a geometric

mean not exceeding 126-cfu/100 mL. A translator developed by VADEQ was used to

convert fecal coliform values to E. coli values.

The General Standard states that waters should be free of substances that are harmful to

aquatic life. The stressor determined to be impacting the aquatic life in the Powell River

and the North and South Fork Powell Rivers is sediment. The sediment endpoints were

calculated from a reference watershed.

Source Assessment

Sources of bacteria and sediment were identified and quantified in the Powell River

drainage area. Sources included point sources as well as nonpoint sources. The

quantification of sources is important to determine the baseline of current conditions that

is causing the impairment. Sources of bacteria included human, livestock, wildlife, pets,

as well as permitted point sources. On the other hand, sediment sources coming from

various activities such as farming and mining, as well as permitted point sources and

streambank erosion were quantified.

Modeling Procedures

Computer modeling is used to relate the sources on the ground to the water quality in the

streams and rivers. This is important since not every colony of bacteria or every amount

of sediment in the Powell River drainage area ends up in the streams and rivers. The

computer models help quantify the portion of bacteria or sediment within the Powell

River drainage area that ends up in the stream.

The computer modeling process consists of several steps. First, the characteristics of the

drainage area including land use, slopes, stream network, soil properties, are entered into

the model. The quantities of bacteria and sediment are also entered into the model. A

process known as calibration is then conducted by comparing model simulations with

monitored field data. Model parameters are adjusted during calibration to minimize the


xl EXECUTIVE SUMMARY

error between simulated and monitored values. This process is conducted for hydrology

(flow) as well as water quality. Once the model is calibrated, it is then used to determine

the existing water quality conditions in the study area and may be used to determine the

reductions necessary to meet the water quality standard or endpoint.

Hydrology

The US Geological Survey (USGS) Hydrologic Simulation Program - Fortran (HSPF)

water quality model was selected as the modeling framework to model hydrology and

fecal coliform loads. For purposes of modeling the Powell River watershed, inputs to

streamflow and in-stream fecal bacteria, the drainage area was divided into 44

subwatersheds.

Daily precipitation data from the Big Stone Gap NCDC Coop station #440735 was used

to model the hydrology of the Powell River watershed. Missing values were filled using

daily precipitation from the Wise 3E NCDC Coop station #449215. The model calibrated

for hydrologic accuracy using daily flow data for the period October 1992 through

September 1996. The modeled output from subwatershed 13 was compared against the

Powell River USGS Gaging Station #03531500 data.

The modeled output was validated for the period of 10/1996 to 9/2000. Simulated flow at

subwatershed 13 was compared with daily observed flow at the Powell River USGS

Gaging Station #03531500.

Fecal Coliform

Wildlife populations, the rate of failure of septic systems, domestic pet populations, and

numbers of livestock are examples of land-based nonpoint sources used to calculate fecal

coliform loads. Also represented in the model were direct sources of uncontrolled

discharges, direct deposition by wildlife, direct deposition by livestock, and direct inputs

from sewer overflows. Contributions from all of these sources were updated to current

conditions to establish existing conditions for the watershed.


EXECUTIVE SUMMARY xli

The fecal coliform calibration was conducted using monitored data collected at VADEQ

monitoring stations listed in Table ES.2. Water Quality validation was conducted using

data collected from VADEQ monitoring stations listed in Table ES.3.

Table ES.2 Bacteria calibration periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area.

Stream Calibration Period Subwatershed Type of Bacteria Used in Calibration

6BPOW193.38 10/1/2000 - 9/30/2003 2 Fecal Coliform 6BPOW179.20 10/1/2000 - 9/30/2003 5 Fecal Coliform 6BPOW165.78 10/1/2000 - 9/30/2003 9 Fecal Coliform 6BPOW138.91 10/1/2000 - 9/30/2003 14 Fecal Coliform 6BBUH000.76 10/1/2000 - 9/30/2003 34 Fecal Coliform 6BPLL004.24 10/1/2000 - 9/30/2003 30 Fecal Coliform 6BPLL000.27 10/1/2000 - 9/30/2003 31 Fecal Coliform 6BPWL001.49 10/1/1997 - 9/30/2000 55 Fecal Coliform 6BWAL000.12 10/1/2002 - 9/30/2004 24 E.coli

Table ES.3 Bacteria validation periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area.

Stream Validation Period Subwatershed Type of Bacteria Used in Validation

6BPOW193.38 10/1/2006 – 1/31/2008 2 E.coli 6BPOW179.20 10/1/1997 – 9/30/2000 5 Fecal coliform 6BPOW165.78 10/1/1997 – 9/30/2000 9 Fecal coliform 6BPOW138.91 10/1/1997 – 9/30/2000 14 Fecal coliform 6BBUH000.76 10/1/2006 – 1/31/2008 34 E.coli 6BPLL006.38 10/1/1997 – 9/30/2000 29 Fecal coliform 6BPLL004.24 10/1/2006 – 1/31/2008 30 E.coli 6BPLL000.27 10/1/2006 – 1/31/2008 31 E.coli 6BPWL006.59 10/1/2002 – 9/30/2005 55 E.coli 6BWAL000.12 10/1/2004 – 9/30/2005 24 E.coli

Sediment

The model used in this study was the Visual BasicTM version of the Generalized

Watershed Loading Functions (GWLF) model with modifications for use with ArcView

(Evans et al., 2001). The target TMDL load for the Powell River watershed is the

average annual load in metric tons per year (t/yr) from the area-adjusted Clinch River


xlii EXECUTIVE SUMMARY

watershed under existing conditions. The Clinch River watershed was used as a

reference watershed since it is meeting the General Standard. To reach the TMDL target

goal (63,927.44 t/yr), different scenarios were run with GWLF.

Load Allocation Scenarios

The next step in the TMDL processes was to reduce the various source loads to levels

that would result in attainment of the water quality standards or endpoints. Scenarios

were evaluated to predict the effects of different combinations of source reductions on

final in-stream water quality. The final TMDL information is shown in Table ES.4.

The final bacterial TMDLs for the Powell River and Tributaries include 100% reductions

in straight pipes and sewer overflows. The final bacterial TMDLs for the Butcher Fork

and Wallen Creek include 100% reductions for both direct livestock and straight pipes.


EXECUTIVE SUMMARY xliii

Table ES.4 Average annual in-stream cumulative pollutant loads modeled after allocation in the Powell River impairments.

Pollutant Units Impairment WLA1 LA MOS TMDL Existing Load

Percent Reduction

E. coli cfu/yr Upper Powell River 4.39E+12 8.28E+13 Implicit 8.72E+13 6.97E+14 79.3%

E. coli cfu/yr Butcher Fork 3.08E+11 2.82E+13 Implicit 2.85E+13 7.48E+13 71.9%

E. coli cfu/yr S.F. Powell River

1.08E+11 1.05E+13 Implicit 1.06E+13 3.81E+13 82.4%

E. coli cfu/yr Middle Powell River 9.65E+12 2.48E+14 Implicit 2.58E+14 1.12E+15 79.9%

E. coli cfu/yr N.F. Powell River 2.17E+12 1.10E+14 Implicit 1.12E+14 5.31E+14 73.4%

E. coli cfu/yr Lower Powell River 1.51E+13 5.43E+14 Implicit 5.58E+14 1.78E+15 77.0%

E. coli cfu/yr Wallen Creek 1.16E+12 1.15E+14 Implicit 1.16E+14 1.89E+14 54.2%

Sediment t/yr Powell River Watershed 1,657.11 55,877.26 6,392.74 63,927.11 91,635.50 37.2%

1 WLA by permit can be found in the corresponding allocation chapters.

Implementation

The goal of the TMDL program is to establish a path that will lead to attainment of water

quality standards. The first step in this process is to develop TMDLs that will result in

meeting water quality standards. This report represents the first phase of that effort for

the impairments in the Powell River watershed. The next step will be more monitoring to

better establish the sources of TSS (see Preface). Development of TMDL

implementation plans (IP) will follow the phased TMDL process. The final step is to

implement the TMDL IPs and to monitor stream water quality to determine if water

quality standards are being attained.


xliv EXECUTIVE SUMMARY

Once a TMDL IP is developed, VADEQ will take the plan to the State Water Control

Board (SWCB) for approval for implementing the pollutant allocations and reductions

contained in the TMDL. Also, VADEQ will request SWCB authorization to incorporate

the TMDL implementation plan into the appropriate waterbody. With successful

completion of implementation plans, Virginia continues the process of restoring impaired

waters and enhancing the value of this important resource.

In some streams for which TMDLs have been developed, factors may prevent the stream

from attaining its designated use. In order for a stream to be assigned, a new designated

use, or a subcategory of a use, the current designated use must be removed. The state

must also demonstrate that attaining the designated use is not feasible. Information is

collected through a special study called a Use Attainability Analysis (UAA). All site-

specific criteria or designated use changes must be adopted by the SWCB as amendments

to the water quality standards regulations. During the regulatory process, watershed

stakeholders and other interested citizens as well as EPA will be able to provide

comments.

Public Participation

During development of the TMDL for the impairments in the Powell River study area,

public involvement was encouraged through a technical advisory committee

(10/21/2008), a first public meeting (10/21/2008), and a final public meeting (1/28/2010).

An introduction of the agencies involved, an overview of the TMDL process, details of

the pollutant sources, and the specific approach to developing the Powell River watershed

TMDLs were presented at the first of the public meeting. Public understanding of, and

involvement in, the TMDL process was encouraged. Input from this meeting was

utilized in the development of the TMDL and improved confidence in the allocation

scenarios. The model simulations and the TMDL load allocations were presented during

the final public meeting. There was a 30-day public comment period after the final

public meeting. Written comments were addressed in the final document.


INTRODUCTION 1-1

1. INTRODUCTION

1.1 Regulations Background

The Clean Water Act (CWA) that became law in 1972 requires that all U.S. streams,

rivers, and lakes meet certain water quality standards. The CWA also requires that states

conduct monitoring to identify waters that are polluted or do not otherwise meet

standards. Through this required program, the state of Virginia has found that many

stream segments do not meet state water quality standards for protection of the six

beneficial uses: recreation/swimming, aquatic life, wildlife, fish consumption, shellfish

consumption, and public water supply (drinking).

When streams fail to meet standards, the stream is “listed” in the current Section 303(d)

report as requiring a Total Maximum Daily Load (TMDL). Section 303(d) of the CWA

and the U.S. Environmental Protection Agency’s (EPA) Water Quality Management and

Planning Regulation (40 CFR Part 130) both require that states develop a Total

Maximum Daily Load (TMDL) for each pollutant. A TMDL is a "pollution budget" for a

stream; that is, it sets limits on the amount of pollution that a stream can tolerate and still

maintain water quality standards. In order to develop a TMDL, background

concentrations, point source loadings, and nonpoint source loadings are considered. A

TMDL accounts for seasonal variations and must include a margin of safety (MOS).

Once a TMDL is developed and approved by EPA, measures must be taken to reduce

pollution levels in the stream. Virginia’s 1997 Water Quality Monitoring, Information

and Restoration Act (WQMIRA) states in section 62.1-44.19:7 that the “Board shall

develop and implement a plan to achieve fully supporting status for impaired waters”.

The TMDL Implementation Plan (IP) describes control measures, which can include the

use of better treatment technology and the installation of best management practices

(BMPs), which should be implemented in a staged process. Through the TMDL process,

states establish water-quality based controls to reduce pollution and meet water quality

standards.


1-2 INTRODUCTION

1.2 Powell River Watershed Characteristics

The majority of the Powell River watershed (USGS Hydrologic Unit Code 06010206) is

located in Lee County and Wise County, Virginia. This watershed is a part of the

Tennessee/Big Sandy River basin, which drains via the Mississippi River to the Gulf of

Mexico. The location of the watershed is shown in Figure 1.1. The drainage area flowing

into the most downstream impairment in this project is approximately 293,000 acres.

Figure 1.1 Location of the Powell River watershed.

The Powell River watershed is located within the level III Central Appalachian and the

level III Ridge and Valley ecoregions in four level IV subsets: Dissected Appalachian

Plateau, Cumberland Mountain Thrust Block, Southern Sandstone Ridges, and Southern

Limestone/Dolomite Valleys and Low Rolling Hills. The level III ecoregions are

described by Purdue University quite well: “The Central Appalachian ecoregion,


INTRODUCTION 1-3

stretching from central Pennsylvania to northern Tennessee, is primarily a high,

dissected, rugged plateau composed of sandstone, shale, conglomerate, and coal. The

rugged terrain, cool climate, and infertile soils limit agriculture, resulting in a mostly

forested land cover. The high hills and low mountains are covered by a mixed

mesophytic forest with areas of Appalachian oak and northern hardwood forest

(www.hort.purdue.edu/newcrop/cropmap/ecoreg/descript.html). The Ridge and Valley

ecoregion description shows “This northeast-southwest trending, relatively low-lying, but

diverse ecoregion is sandwiched between generally higher, more rugged mountainous

regions with greater forest cover. As a result of extreme folding and faulting events, the

region’s roughly parallel ridges and valleys have a variety of widths, heights, and

geologic materials, including limestone, dolomite, shale, siltstone, sandstone, chert,

mudstone, and marble. Springs and caves are relatively numerous. Present-day forests

cover about 50% of the region. The ecoregion has a diversity of aquatic habitats and

species of fish” (www.hort.purdue.edu/newcrop/cropmap/ecoreg/descript.html).

The Powell River watershed is comprised of many different SSURGO (Soil Survey

Geographic) soils. The majority of the area is comprised of four soil complexes: Berks-

Pineville-Rock outcrop complex, Frederick-Carbo-Timberville complex, Carbo-

Chilhowie-Frederick complex, and Kimber-Shelocta-Hazleton complex (NRCS, 2008a).

Soils in the area are generally moderately deep to very deep, well-drained, and

moderately permeable.

As for the climatic conditions in the southern end of the Powell River watershed, during

the period from 1931 to 2007 Pennington Gap, Virginia (NCDC station# 446626)

received an average annual precipitation of approximately 49 inches, with 47% of the

precipitation occurring during the May through October growing season (SERCC, 2008).

Average annual snowfall is 17 inches, with the highest snowfall occurring during January

(SERCC, 2008). The highest average daily temperature of 85.5 ºF occurs in July, while

the lowest average daily temperature of 45.2 ºF occurs in January (SERCC, 2008).

For the northern end of the watershed, during the period from 1955 to 2007, the weather

station at Wise, Virginia (NCDC station# 449215) received an average annual

http://www.hort.purdue.edu/newcrop/cropmap/ecoreg/descript.html�

http://www.hort.purdue.edu/newcrop/cropmap/ecoreg/descript.html�


1-4 INTRODUCTION

precipitation of approximately 47 inches, with 51% of the precipitation occurring during

the May through October growing season (SERCC, 2008). Average annual snowfall is

approximately 14 inches, with the highest snowfall occurring during January (SERCC,

2008). The highest average daily temperature of 80.9 ºF occurs in July, while the lowest

average daily temperature of 42.2 ºF occurs in January (SERCC, 2008).

Land use in the study area was characterized using the National Land Cover Database

2001 (NLCD). The drainage area is predominantly forest with woodlands covering

approximately 73% of the area. Pasture and hay land covers account for roughly 18% of

the drainage area. Developed, mining, and water land uses account for the remainder of

the study area. More detailed breakdown of land use by impairment will be provided in

Section 4.2.2.

1.3 Powell River Impairments

There are five different impaired streams in this study, North Fork Powell River, South

Fork Powell River, the Powell River, Butcher Fork, and Wallen Creek. There are four

separate impaired segments of the Powell River and three separate impairments on the

South Fork Powell River, making a total of 10 impaired segments included in this study.

In the sections below each impaired stream segment is described.

1.3.1 Butcher Fork (VAS-P18R_BUH01A04)

Butcher Fork in Wise County, VA flows Southwest into the South Fork Powell River. Its

headwaters are near Norton, VA and its outlet is between Big Stone Gap and East Stone

Gap, VA.

Butcher Fork, from the headwaters to the confluence with the South Fork Powell River,

was initially listed in 2004 as impaired for not supporting the recreation/swimming use.

Monitoring at station 6BBUH000.76 showed 4 bacteria standard violations out of 8

samples.

The same segment of Butcher Fork, updated to 4.86 miles of stream, was listed again in

2006. The monitoring showed 5 violations out of 12 bacteria samples. Figure 1.2 and

Table 1.1 show more details about the Butcher Fork impairment.


INTRODUCTION 1-5

1.3.2 South Fork Powell River (VAS-P18R_PLL01A98)

The South Fork Powell River in Wise County, VA has its headwaters near Norton, VA,

flows through the Big Cherry Reservoir, then flows through East Stone Gap, VA and

flows around the south of Big Stone Gap, VA before emptying into the Powell River.

A 3.71-mile segment of South Fork Powell River was listed as impaired on the 1998

303(d) list by EPA. This segment, from the Butcher Fork confluence to the outlet at the

Powell River, does not support the aquatic life use. Biological monitoring at

6BPLL002.55 in 1996 showed South Fork Powell River as moderately impaired.

This same segment of South Fork Powell River remained on the 2006 303(d) list for not

supporting the aquatic life use. Figure 1.2 and Table 1.1 show more details about the

South Fork Powell River impairments.


This impaired segment was added to the 2004 impaired waters list for not supporting the

aquatic life use. This impaired segment extends from the confluence with Beaverdam

Creek upstream and ends at the confluence with Butcher Fork downstream. Biological

monitoring at 6BPLL004.49 in 1999 showed South Fork Powell River as moderately

impaired. No impairment was detected in another monitoring event conducted at

6BPLL004.49 in 1998. Based on these results, additional monitoring was recommended.

The DEQ factsheet lists loss of riparian habitat and unknown sources as reason behind

impairment.

This same segment of South Fork Powell River remained on the 2006 303(d) list for not

supporting the aquatic life use. Figure 1.2 and Table 1.1 show more details about the

South Fork Powell River impairments.


Additional segments were listed on the 2004 303(d) list. South Fork Powell River from

the Big Cherry Reservoir to Beaverdam Creek was listed as not supporting the

recreation/swimming use. Samples collected a station 6BPLL06.38 had 6 bacteria

standard violations out of 18 total samples. This segment was listed again on the 2006


1-6 INTRODUCTION

303(d) list for not supporting the recreation/swimming use. Figure 1.2 and Table 1.1

show more details about the South Fork Powell River impairments.

1.3.5 North Fork Powell River (VAS-P20R_PWL01A00)

The North Fork Powell River in Lee County, VA has its headwaters near the Wise

County border. It flows southwest, parallel to the Powell River, then flows through

Pocket, VA and abruptly curves south through Pennington Gap, VA before emptying into

the Powell River.

A small segment of the North Fork Powell River, 3.94 miles, from the Straight Creek

confluence to the Cane Creek confluence was initially listed in 1996 as impaired for not

supporting the aquatic life use and the recreation/swimming use. Four biological samples

have resulted in moderate impairment ratings. The biological monitoring station in

Pennington Gap shows poor habitat, high embeddedness, moderate deposition, and sub-

optimal habitat diversity. This segment was again listed as impaired on the 1998 list.

In the 2002 assessment, the impaired segment length of the North Fork Powell River was

increased to 6.03 miles and extended from the Straight Creek confluence to the Powell

River. This segment was only listed as impaired for not supporting the aquatic life use.

In the 2004 303(d) list, the North Fork Powell River was, once again, listed as impaired

for not supporting the aquatic life use and the recreation/swimming use. Water

monitoring in 2004 at station 6BPWL001.49 resulted in 4 samples out of 18 samples

violating the bacteria standard.

The 2006 assessment resulted in the same segment of North Fork Powell River listed as

impaired for not supporting both the aquatic life use and the recreation/swimming use.

Bacteria concentrations in water samples at stations 6BPWL001.49 and 6BPWL004.10

exceeded the bacteria standard 8 out of 20 and 2 out of 12 times, respectively. Biological

surveys during 2003 and 2004 at 6BPWL004.40 indicated the North Fork Powell River is

slightly impaired. Figure 1.2 and Table 1.1 show more details about the of North Fork

Powell River impairments.


INTRODUCTION 1-7

1.3.6 Wallen Creek (VAS-P22R_WAL01A00)

Wallen Creek in Lee County, VA flows southwest along the Lee and Scott County

border, between Wallen Ridge and Powell Mountain, through Stickleyville, VA. It

follows Route 612, then curves north before emptying into the Powell River.

The 2006 list states Wallen Creek is impaired for not supporting the recreation/swimming

use. Water samples at station 6BWAL000.12 resulted in 2 bacteria violations out of 8

samples. Figure 1.2 and Table 1.1 show more details about the Wallen Creek

impairment.

1.3.7 Powell River

Separate TMDLs will be calculated for four separate sections of the Powell River for the

different impaired uses: aquatic life use (benthic) and recreation/swimming (E. coli).

Descriptions of the different impaired segments of Powell River are described from

upstream to downstream.

Figure 1.2 shows the impaired segments in the Powell River watershed as they are

described in the 2006 list. Table 1.1 describes the segment name and identification

number, the impairments, the initial 303(d) listing year, the length of the impairment in

river miles as it was listed in 2006, the listing number of bacteria violations over the total

samples, the number of bacteria violations over the total samples for the 2006 assessment

time period, and the impaired stream segment description.

1.3.7.1 Powell River (VAS-P17R_POW01A94)

This segment of the Powell River is in Wise County, VA, flows through Appalachia, VA,

then between Little Stone Mountain and Stone Mountain following US-23. This segment

of the Powell River was initially listed on the 1996 303(d) list for not supporting the

recreation/swimming use. Violations of the bacteria standard of 58% of the samples were

observed at station 6BPOW180.78. This segment remained on the 1998 list.

This segment was listed on the 2002 303(d) list for not supporting both the aquatic life

use and the recreation/swimming use. The segment length was updated to 2.62 miles of

stream. Data from the biological monitoring station 6BPOW180.72 showed a moderate


1-8 INTRODUCTION

impairment rating. Water samples from station 6BPOW180.78 resulted in 4 bacteria

standard violations out of 36 samples.

The listing did not change during the 2004 assessment, stating this segment was not

supporting the aquatic life use and the recreation/swimming use. Water samples showed

11 out of 41 violations of the bacteria standard at station 6BPOW180.78. The moderately

impaired rating remained.

This segment remained listed on the 2006 303(d) list for not supporting both the aquatic

life use and the recreation/swimming use. Two water monitoring stations,

6BPOW179.20 and 6BPOW180.762, both showed violations of the bacteria standard,

44% and 58%, respectively. The most recent biological survey in 2003 resulted in a

slightly impaired rating.


The next downstream segment of the Powell River included in this study extends from

the confluence with Poor Valley Creek to the upper end of the public water supply (river

mile 161.62). This segment of the Powell River is in Lee County, VA, flows near

Dryden, VA, and ends approximately 1.3 miles below the Clear Spring Branch

confluence.

The 6.38-mile segment was initially listed on the 2004 303(d) list as impaired for not

supporting both the aquatic life use and the recreation/swimming use. Water sampling at

station 6BPOW165.78 resulted in 5 bacteria violations out of 46 samples. Biological

monitoring at station 6BPOW166.92 resulted in a moderately impaired rating.

The length of this segment was updated to 6.37 miles in the 2006 list. The segment was

listed again for not supporting both the aquatic life use and the recreation/swimming use.

The Powell River at station 6BPOW165.78 had 3 water samples that violated the bacteria

standard out of 25 samples.


INTRODUCTION 1-9


This segment of the Powell River extends from the confluence with Station Creek to the

confluence with Town Branch. This segment of the Powell River is in Lee County, VA

and was just recently listed as impaired on the 2006 303(d) list for not supporting the

recreation/swimming use. Water samples collected at station 6BPOW138.91 resulted in

3 violations of the bacteria standard out of 19 samples.


The most downstream segment of the Powell River included in this study extends from

the confluence with Hardy Creek to the confluence with Yellow Creek. This segment of

the Powell River is in Lee County, VA near the Tennessee border.

The 8.42-mile segment was initially listed on the 2002 303(d) list as impaired for not

supporting the aquatic life use. Biological monitoring at station 6BPOW120.12 resulted

in a moderately impaired rating. This segment was listed again on the 2004 and 2006

lists. The most recent biological survey indicates a slightly impaired rating.

TMD

L Developm

ent

Powell R

iver and Tributaries, VA

1-10

INTR

OD

UC

TION

Figure 1.2 The impaired segments in the Powell River watershed.

TMD

L Developm

ent

Powell River and Tributaries, VA

INTR

OD

UC

TION

1-11

Table 1.1 Impairments within the Powell River watershed included in this study.

Stream Name Impairment ID

Impairment(s) Contracted

Initial Listing Year

2006 River Miles

Listing year Violations1/

Total Samples

2006 Listing Violations2/

Total SamplesImpairment Location Description

Butcher Fork VAS-P18R_BUH01A04 E. coli 2004 4.86 4/8 5/12 FC Headwaters to South Fork Powell River conf.

South Fork Powell River VAS-P18R_PLL02A00 E. coli 2004 6.33 6/18 6/18 FC Big Cherry Reservoir to Beaverdam Creek

South Fork Powell River VAS-P18R_PLL01A02 Benthic 1998 1.90 NA NA Beaverdam Creek to Butcher Fork

South Fork Powell River VAS-P18R_PLL01A98 Benthic 1998 3.71 NA NA Butcher Fork to the Powell River

North Fork Powell River VAS-P20R_PWL01A00 Benthic, E. coli 1996, 2004 6.02 4/18 8/20 FC

2/12 E. coli Straight Creek conf. to Powell River conf.

Wallen Creek VAS-P22_WAL01A00 E. coli 2006 2.03 2/8 2/8 Lone Branch to Powell River

Powell River VAS-P17R_POW01A94 Benthic, E. coli 1996, 1996 2.62 NA 14/36 FC

4/11 E. coli Roaring Branch conf. to Dakota St. in Big Stone Gap, VA

Powell River VAS-P19R_POW03A00 Benthic, E. coli 2004, 2004 6.37 5/46 3/25 FC Poor Valley Creek conf. to Public Water Supply

Powell River VAS-P21R_POW02A02 E. coli 2006 12.69 3/19 3/19 E. coli Station Creek conf. to Town Branch conf.

Powell River VAS-P23R_POW02A00 Benthic 2002 8.43 NA NA Hardy Creek conf. to Yellow Creek conf.

FC = Fecal Coliform 1 Based on the interim instantaneous fecal coliform standard of 400 cfu/100mL for samples collected during the assessment period. 2 Based on the instantaneous fecal coliform standard of 400 cfu/100mL and/or the instantaneous E. coli standard of 235 cfu/100mL for samples collected during the assessment period


TMDL ENDPOINT AND WATER QUALITY ASSESSMENT 2-1

2. TMDL ENDPOINT AND WATER QUALITY ASSESSMENT

2.1 Applicable Water Quality Standards

According to 9 VAC 25-260-5 of Virginia's State Water Control Board Water Quality

Standards, the term "water quality standards" means "…provisions of state or federal law

which consist of a designated use or uses for the waters of the Commonwealth and water

quality criteria for such waters based upon such uses. Water quality standards are to

protect the public health or welfare, enhance the quality of water and serve the purposes

of the State Water Control Law and the federal Clean Water Act".

As stated in Virginia state law 9 VAC 25-260-10 (Designation of uses),

A. All state waters, including wetlands, are designated for the following uses: recreational uses, e.g., swimming and boating; the propagation and growth of a balanced, indigenous population of aquatic life, including game fish, which might reasonably be expected to inhabit them; wildlife; and the production of edible and marketable natural resources, e.g., fish and shellfish.

♦ D. At a minimum, uses are deemed attainable if they can be achieved by the imposition of effluent limits required under §§301(b) and 306 of the Clean Water Act and cost-effective and reasonable best management practices for nonpoint source control.

Virginia adopted its current E. coli and enterococci standard in January 2003. E. coli and

enterococci are both bacteriological organisms that can be found in the intestinal tract of

warm-blooded animals; there is a strong correlation between these and the incidence of

gastrointestinal illness. Like fecal coliform bacteria, these organisms indicate the

presence of fecal contamination.

The criteria which were used in developing the bacteria TMDL in this study are outlined

in Section 9 VAC 25-260-170 and read as follows:

A. In surface waters, except shellfish waters and certain waters identified in subsection B of this section, the following criteria shall apply to protect primary contact recreational uses:



1. Fecal coliform bacteria shall not exceed a geometric mean of 200 fecal coliform bacteria per 100 ml of water for two or more samples over a calendar month nor shall more than 10% of the total samples taken during any calendar month exceed 400 fecal coliform bacteria per 100 ml of water. This criterion shall not apply for a sampling station after the bacterial indicators described in subdivision 2 of this subsection have a minimum of 12 data points or after June 30, 2008, whichever comes first.

2. E. coli and enterococci bacteria per 100 ml of water shall not exceed the following:

Geometric Mean1 Single Sample Maximum2

Freshwater3 E. coli 126 235

Saltwater and Transition Zone3

enterococci 35 104

1 For two or more samples taken during any calendar month. 2 No single sample maximum for enterococci and E. coli shall exceed a 75% upper one-sided confidence limit based on a site-specific log standard deviation. If site data are insufficient to establish a site-specific log standard deviation, then 0.4 shall be used as the log standard deviation in freshwater and 0.7 shall be as the log standard deviation in saltwater and transition zone. Values shown are based on a log standard deviation of 0.4 in freshwater and 0.7 in saltwater. 3 See 9 VAC 25-260-140 C for freshwater and transition zone delineation.

2.2 Selection of a TMDL Endpoint

The first step in developing a TMDL is the establishment of in-stream numeric endpoints,

which are used to evaluate the attainment of acceptable water quality. In-stream numeric

endpoints, therefore, represent the water quality goals that are to be achieved by

implementing the load reductions specified in the TMDL. For the bacteria impairments

in the Powell River watershed, the applicable endpoints and associated target values can

be determined directly from the Virginia water quality regulations. In order to remove a

waterbody from a state’s list of impaired waters, the Clean Water Act requires

compliance with that state’s water quality standard.

The in-stream E. coli target for the TMDLs in this study was a monthly geometric mean

not exceeding 126 cfu/100 mL.



2.3 Discussion of In-stream Water Quality

This section provides an inventory and analysis of available observed in-stream fecal

bacteria monitoring data in the watershed of the Powell River watershed. An

examination of data from water quality stations used in the 303(d) assessment was

performed. Sources of data and pertinent results are discussed.

2.3.1 Inventory of Water Quality Monitoring Data

The primary sources of available water quality information are:

Bacteria enumerations from 39 VADEQ in-stream monitoring stations with date from

February 1980 to December 2009,

Bacterial source tracking at 5 VADEQ stations.

2.3.1.1 VADEQ Water Quality Monitoring for TMDL Assessment

Data from in-stream water samples, collected at VADEQ monitoring stations from

February 1980 to December 2009 (Figure 2.1), were analyzed for fecal coliform (Table

2.1) and E.coli (Table 2.2). Samples were taken for the express purpose of determining

compliance with the state instantaneous bacteria standards. Until recent years, and as a

matter of economy, samples showing fecal coliform concentrations below 100 cfu/100

mL or in excess of a specified cap (e.g., 8,000 or 16,000 cfu/100 mL, depending on the

laboratory procedures employed for the sample) were not analyzed further to determine

the precise concentration of fecal coliform bacteria. The result is that reported values of

100 cfu/100 mL most likely represent concentrations below 100 cfu/100 mL, and

reported concentrations of 8,000 or 16,000 cfu/100 mL most likely represent

concentrations in excess of these values. Information in the tables is arranged in

alphabetical order by stream name then from downstream to upstream station location.



Figure 2.1 Location of VADEQ water quality monitoring stations in the Powell River watershed.

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Table 2.1 Summary of fecal coliform (cfu/100mL) data collected by VADEQ from January 1980 – December 2009. VADEQ Count Minimum Maximum Mean Median Standard Violations1 Violations2

Stream Station (#) (cfu/100mL) (cfu/100mL) (cfu/100mL) (cfu/100mL) Deviation % % Batie Creek 6BBAT000.01 1 1,400 1,400 1,400 1,400 NA 100% 100%

Batie Creek, East Fork 6BBTE000.02 5 210 4,500 1,350 670 1,793 40% 60% Batie Creek, West Fork 6BBTW000.05 5 20 1,400 454 100 604 20% 40%

Butcher Fork 6BBUH000.76 12 100 3,900 842 300 1,144 25% 42% North Fork Powell River 6BPWL000.06 1 75 75 75 75 NA 0% 0% North Fork Powell River 6BPWL001.49 148 0 22,800 3,038 1,150 4,057 53% 67% North Fork Powell River 6BPWL004.10 12 25 1,000 333 275 313 0% 25%

Powell River 6BPOW138.91 107 0 1,800 119 50 218 1% 6% Powell River 6BPOW143.53 136 0 20,000 978 100 2,356 20% 29% Powell River 6BPOW156.57 1 100 100 100 100 NA 0% 0% Powell River 6BPOW162.89 1 25 25 25 25 NA 0% 0% Powell River 6BPOW165.78 95 0 6,000 275 100 728 4% 9% Powell River 6BPOW170.76 1 580 580 580 580 NA 0% 100% Powell River 6BPOW179.20 179 0 12,000 1,826 600 2,438 41% 60% Powell River 6BPOW193.38 12 100 3,800 1,117 750 1,152 33% 67% Roaring Fork 6BRIN001.84 12 100 400 142 100 100 0% 0%

South Fork Powell River 6BPLL000.27 12 100 4,700 558 100 1,310 8% 8% South Fork Powell River 6BPLL004.24 12 100 600 263 300 164 0% 8% South Fork Powell River 6BPLL006.38 28 0 5,200 453 100 1,000 7% 29% South Fork Powell River 6BPLL012.79 8 100 1,700 300 100 566 13% 13% South Fork Powell River 6BPLL012.99 7 100 100 100 100 0 0% 0% South Fork Powell River 6BPLL013.59 7 100 100 100 100 0 0% 0%

Wallen Creek 6BWAL005.97 1 25 25 25 25 NA 0% 0% NA – Not applicable 1 Based on the interim instantaneous fecal coliform standard of 1000 cfu/100mL. 2 Based on the instantaneous fecal coliform standard of 400 cfu/100mL.

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Table 2.2 Summary of E. coli (cfu/100mL) data collected by VADEQ from May 2002 – December 2009. VADEQ Count Minimum Maximum Mean Median Standard Violations1

Stream Station (#) (cfu/100mL) (cfu/100mL) (cfu/100mL) (cfu/100mL) Deviation % Bundy Creek 6BBUY000.01 6 25 75 33 25 20 0.0% Butcher Fork 6BBUH000.76 9 6 350 132 50 133 22%

Dry Creek 6BDBR001.69 5 25 700 203 120 281 20% Hardy Creek 6BHAR000.34 17 25 1,200 261 150 304 41.2% Jones Creek 6BJON000.46 6 25 380 117 25 151 17% Mud Creek 6BMDC000.33 12 25 1,000 235 100 305 25.0%

North Fork Powell River 6BPWL001.49 18 25 880 224 135 223 27.8% North Fork Powell River 6BPWL004.10 18 10 920 207 160 233 33.3% North Fork Powell River 6BPWL006.59 18 25 300 75 38 72 5.6% North Fork Powell River 6BPWL010.36 18 25 75 31 25 14 0.0% North Fork Powell River 6BPWL017.03 6 25 75 38 25 21 0.0%

Poor Valley Creek 6BPVC000.18 11 25 350 78 25 101 9.1% Powell River 6BPOW138.91 51 10 620 79 25 124 9.8% Powell River 6BPOW165.78 18 25 180 42 25 38 0.0% Powell River 6BPOW179.20 17 25 1,100 187 50 288 23.5% Powell River 6BPOW193.38 12 50 1,100 388 365 293 75.0% Powell River 6BPOW194.75 12 25 280 88 63 79 8.3% Roaring Fork 6BRIN001.84 15 25 300 53 25 71 6.7%

South Fork Powell River 6BPLL000.27 18 25 750 166 100 203 22.2% South Fork Powell River 6BPLL002.55 12 25 420 180 150 142 33% South Fork Powell River 6BPLL004.24 6 25 300 158 150 138 50% South Fork Powell River 6BPLL006.38 3 1 25 15 20 13 0% South Fork Powell River 6BPLL012.79 7 25 25 25 25 0 0% South Fork Powell River 6BPLL012.99 7 25 25 25 25 0 0% South Fork Powell River 6BPLL013.59 7 25 25 25 25 0 0%

Town Branch 6BTOW001.32 16 25 1,600 314 178 413 31.3% Town Creek 6BTOW003.82 5 25 2000 515 75 843 40%

1 Based on the current instantaneous E. coli standard of 235 cfu/100mL.

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Table 2.2 Summary of E. coli (cfu/100mL) data collected by VADEQ from May 2002 – December 2009 (cont.).

Stream VADEQ Count Minimum Maximum Mean Median Standard Violations1

Station (#) (cfu/100mL) (cfu/100mL) (cfu/100mL) (cfu/100mL) Deviation % Wallen Creek 6BWAL014.54 6 25 950 312 160 356 33% Wallen Creek 6BWAL026.64 6 25 400 208 210 167 50% Wallen Creek 6BWAL000.12 17 25 900 189 120 230 23.5%

1 Based on the current instantaneous E. coli standard of 235 cfu/100mL.


2-8 TMDL ENDPOINT AND WATER QUALITY ASSESSMENT

2.3.1.2 Bacterial Source Tracking

MapTech, Inc. was contracted to perform an analysis of E. coli concentrations as well as

bacterial source tracking (BST) for five (5) sites in the Powell River watershed. Two of

these locations were on the Powell River, one on the North Fork Powell River, one on the

S.F. Powell River and one on Butcher Fork. BST is intended to aid in identifying sources

(i.e., human, pets, livestock, or wildlife) of fecal contamination in water bodies. Data

collected provided insight into the likely sources of fecal contamination, aided in

distributing fecal loads from different sources during model calibration, and will improve

the chances for success in implementing solutions.

Several procedures are currently under study for use in BST. Virginia has adopted the

Antibiotic Resistance Analysis (ARA) methodology implemented by MapTech’s

Environmental Diagnostics Laboratory (EDL). This method was selected because it has

been demonstrated to be a reliable procedure for confirming the presence of human, pet,

livestock and wildlife sources in watersheds in Virginia. The results were reported as the

percentage of isolates acquired from the sample that were identified as originating from

either humans, pets, livestock, or wildlife.

The BST results of water samples collected at the five stations in the Powell River

watershed are reported in Tables 2.3 through 2.7. The locations of these stations are

shown in Figure 2.2. The E. coli enumerations are given to indicate the bacteria

concentrations at the time of sampling. Bold values in this column represent samples that

exceeded the current E.coli instantaneous (single sample) standard of 235 cfu/100mL.

The proportions (%) reported are formatted to indicate statistical significance (i.e., Bold

numbers indicate a statistically significant result). The statistical significance was

determined through two tests. The first test was based on the sample size. A z-test was

used to determine if the proportion was significantly different from zero (alpha = 0.10).

Second, the rate of false positives was calculated for each source category in each library,

and a proportion was not considered significantly different from zero unless it was

greater than the false-positive rate plus three standard deviations.



Table 2.3 Summary of bacterial source tracking results from water samples collected at the Powell River station (6BPOW179.20).

Percent Isolates classified as2: Date Number

of Isolates

E. coli1 (cfu/100

mL) Wildlife Human Livestock Pet

7/21/2003 24 210 17% 4% 46% 33% 8/20/2003 24 610 12% 55% 8% 25% 9/17/2003 24 2000 51% 12% 25% 12%

10/15/2003 24 670 84% 4% 8% 4% 11/17/2003 24 460 29% 0% 71% 0% 12/16/2003 24 156 17% 37% 17% 29% 1/12/2004 24 134 12% 71% 0% 17% 2/17/2004 24 158 0% 75% 21% 4% 3/17/2004 24 580 80% 8% 8% 4% 4/20/2004 10 130 20% 20% 10% 50% 5/12/2004 1 1 100% 0% 0% 0% 6/21/2004 24 290 0% 71% 8% 21%

1Bold type indicates this sample violates the instantaneous standard (235 cfu/100mL). 2Bold type indicates a statistically significant value.

Table 2.4 Summary of bacterial source tracking results from water samples collected at the Powell River station (6BPOW180.62).


of Isolates

E. coli1 (cfu/100


7/21/2003 24 270 12% 8% 59% 21% 8/20/2003 24 200 12% 59% 12% 17% 9/17/2003 16 190 19% 25% 50% 6%

10/15/2003 24 1600 67% 8% 25% 0% 11/17/2003 24 320 12% 0% 88% 0% 12/16/2003 24 138 4% 71% 8% 17% 1/12/2004 24 170 50% 38% 4% 8% 2/17/2004 24 610 29% 25% 17% 29% 3/17/2004 24 154 54% 25% 21% 0% 4/20/2004 24 300 50% 25% 25% 0% 5/12/2004 24 360 25% 29% 0% 46% 6/21/2004 24 460 4% 63% 12% 21%




Table 2.5 Summary of bacterial source tracking results from water samples collected at the North Fork Powell River station (6BPWL001.49).


of Isolates

E. coli1 (cfu/100


7/21/2003 24 250 38% 33% 12% 17% 8/20/2003 24 320 51% 12% 33% 4% 9/17/2003 20 180 35% 20% 45% 0%

10/15/2003 24 1700 12% 29% 47% 12% 11/17/2003 24 480 25% 0% 63% 12% 12/16/2003 24 48 42% 21% 25% 12% 1/12/2004 13 20 38% 47% 15% 0% 2/17/2004 24 120 8% 46% 25% 21% 3/17/2004 24 126 8% 58% 17% 17% 4/20/2004 24 540 59% 25% 12% 4% 5/12/2004 24 120 12% 0% 42% 46% 6/21/2004 23 250 4% 57% 17% 22%


Table 2.6 Summary of bacterial source tracking results from water samples collected at the South Fork Powell River station (6BPLL006.38).


of Isolates

E. coli1 (cfu/100


2/12/2008 NVI 1 NA NA NA NA 3/26/2008 1 30 100% 0% 0% 0% 4/16/2008 4 6 50% 50% 0% 0% 5/27/2008 24 260 54% 38% 8% 0% 6/30/2008 23 90 70% 0% 4% 26% 7/21/2008 13 156 31% 38% 23% 8% 8/18/2008 24 240 72% 8% 12% 8% 9/22/2008 12 150 17% 58% 17% 8%

10/27/2008 19 450 11% 57% 21% 11% 11/12/2008 18 310 39% 33% 17% 11% 12/15/2008 23 118 44% 13% 17% 26% 1/13/2009 4 12 50% 25% 0% 25%

1Bold type indicates this sample violates the instantaneous standard (235 cfu/100mL). 2Bold type indicates a statistically significant value. NVI no viable isolates, NA not applicable.



Table 2.7 Summary of bacterial source tracking results from water samples collected at the Butcher Fork station (6BBUH000.76).


of Isolates

E. coli1 (cfu/100


1/15/2008 24 50 50% 12% 17% 21% 2/12/2008 3 6 0% 100% 0% 0% 3/26/2008 1 30 0% 100% 0% 0% 4/16/2008 23 34 30% 40% 13% 17% 5/27/2008 8 210 25% 50% 0% 25% 6/30/2008 16 200 75% 25% 0% 0% 7/21/2008 24 120 80% 12% 8% 0% 8/18/2008 24 400 88% 8% 0% 4% 9/22/2008 21 140 81% 0% 5% 14%

10/27/2008 7 106 43% 14% 43% 0% 11/12/2008 9 30 11% 67% 0% 22% 12/15/2008 9 890 56% 11% 22% 11%




Figure 2.2 Location of BST water quality monitoring stations in the Powell River watershed.


BACTERIA SOURCE ASSESSMENT 3-1

3. BACTERIA SOURCE ASSESSMENT

The TMDL development described in this report includes examination of all potential

sources of fecal coliform in the Powell River. The source assessment was used as the

basis of model development and ultimate analysis of TMDL allocation options. In

evaluation of the sources, loads were characterized by the best available information,

landowner input, literature values, and local management agencies. This section

documents the available information and interpretation for the analysis. The source

assessment chapter is organized into point and nonpoint sections. The representation of

the following sources in the model is discussed in Chapter 4.

3.1 Assessment of Permitted Sources

Nine point sources, some with multiple outfalls, are permitted to discharge to surface

water bodies in the Powell River study area through the Virginia Pollutant Discharge

Elimination System (VPDES). These are listed in Table 3.1. The use of “UT” in this

table refers to unnamed tributaries. Permitted point discharges that may contain

pathogens associated with fecal matter are required to maintain a fecal coliform

concentration below 200 cfu/100 mL. Currently, these permitted discharges are expected

not to exceed the 126 cfu/100mL E. coli standard. One method for achieving this goal is

chlorination. Chlorine is added to the discharge stream at levels intended to kill

pathogens. The monitoring method for ensuring the goal is to measure the concentration

of total residual chlorine (TRC) in the effluent. Typically, if minimum TRC levels are

met, bacteria concentrations are reduced to levels well below the standard.

Table 3.2 shows the 36 single family home permits within the Powell River study area.

These permits allow treated residential wastewater to be discharged to surface waters.

All of these housing units discharge water and bacteria to the streams.

There are no VPDES Confined Animal Feeding Operations (CAFO) or Virginia Pollution

Abatement (VPA) facilities in the study area.

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Table 3.1 Summary of VPDES permitted point sources permitted for fecal coliform (FC) control in the Powell River study area.

Permitted for Permit Receiving Stream(s) Facility Name

FC Control VA0020940 Powell River Big Stone Gap Regional WWTP Yes VA0029599 Powell River, North Fork Pennington Gap STP Yes VA0052311 South Fork Powell River Big Stone Gap Water Treatment Plant No VA0052337 Ben's Branch Appalachia WTP No VA0053023 Powell River Pennington Gap Water Plant No

VA0060798 Mill Branch Wise County Public Schools - Appalachia E S STP Yes

VA0063941 Station Creek Dot Mobile Home Park STP Yes

VA0075515 Powell River Lee County Public Service Authority - Cross Creek Yes

VA0089397 Powell River Lee County PSA - Hickory Flats WWTP Yes



Table 3.2 Single family home permits in the Powell River study area. Permit Receiving Stream Facility Type

VAG400227 Butcher Fork Private Residence VAG400016 Butcher Fork Private Residence VAG400383 Pigeon Creek Private Residence VAG400392 Powell River Private Residence VAG400395 Beaverdam Creek Private Residence VAG400505 Powell River Private Residence VAG400089 Thacker Branch Private Residence VAG400253 Wildcat Creek Private Residence VAG400049 South Fork Powell River Private Residence VAG400347 Beaverdam Creek UT Private Residence VAG400517 Powell River Private Residence VAG400373 Butcher Fork Private Residence VAG400135 Bear Branch Private Residence VAG400151 Wildcat Creek Private Residence VAG400166 Butcher Fork Private Residence VAG400275 Butcher Fork Private Residence VAG400281 Wildcat Creek Private Residence VAG400228 Butcher Fork Private Residence VAG400099 Beaverdam Creek Private Residence VAG400117 Crab Orchard Creek Private Residence VAG400128 Butcher Fork Private Residence VAG400462 Butcher Fork Private Residence VAG400470 Beaverdam Creek Private Residence

VAG400169 Beaverdam Creek Private Residence

VAG400748 Beaverdam Creek UT Private Residence

VAG400640 Powell River Private Residence

VAG400389 Butcher Fork Private Residence




VAG400711 South Fork Powell River Private Residence





VAG400715 Thacker Branch Private Residence


3-4 BACTERIA SOURCE ASSESSMENT

3.2 Assessment of Nonpoint Sources

In the Powell River study area, both urban and rural nonpoint sources of fecal coliform

bacteria were considered. Sources include residential sewage treatment systems, land

application of waste (livestock), biosolids, livestock, wildlife, and pets. Sources were

identified and enumerated. MapTech previously collected samples of fecal coliform

sources (i.e., wildlife, livestock, pets, and human waste) and enumerated the density of

fecal coliform bacteria. This analysis was used to support the modeling process for the

current project and to expand the database of known fecal coliform sources for purposes

of bacterial source tracking (Section 2.3.1.2). Where appropriate, spatial distribution of

sources was also determined.

3.2.1 Private Residential Sewage Treatment

Population, housing units, and type of sewage treatment from U.S. Census Bureau were

calculated using GIS (Table 3.3). In the U.S. Census questionnaires, housing occupants

were asked which type of sewage disposal existed. Houses can be connected to a public

sanitary sewer, a septic tank, or a cesspool, or the sewage is disposed of in some other

way. The Census category “Other Means” includes the houses that dispose of sewage

other than by public sanitary sewer or a private septic system. The houses included in

this category are assumed to be disposing of sewage via a pit-privy or through the use of

a straight pipe (direct stream outfall).

Sanitary sewers are piping systems designed to collect wastewater from individual homes

and businesses and carry it to a wastewater treatment plant. Sewer systems are designed

to carry a specific "peak flow" volume of wastewater to the treatment plant. Within this

design parameter, sanitary collection systems are not expected to overflow, surcharge or

otherwise release sewage before their waste load is successfully delivered to the

wastewater treatment plant.

When the flow of wastewater exceeds the design capacity or the capacity is reduced by a

blockage, the collection system will "back up" and sewage discharges through the nearest

escape location. These discharges into the environment are called overflows.



Wastewater can also enter the environment through exfiltration caused by line cracks,

joint gaps, or breaks in the piping system.

Typical private residential sewage treatment systems (septic systems) consist of a septic

tank, distribution box, and a drainage field. Waste from the household flows first to the

septic tank, where solids settle out and are periodically removed by a septic tank pump-

out. The liquid portion of the waste (effluent) flows to the distribution box, where it is

distributed among several buried, perforated pipes that comprise the drainage field. Once

in the soil, the effluent flows downward to groundwater, laterally to surface water, and/or

upward to the soil surface. Removal of fecal coliform is accomplished primarily by die-

off during the time between introduction to the septic system and eventual introduction to

naturally occurring waters. Properly designed, installed, and functioning septic systems

contribute virtually no fecal coliform to surface waters.

A septic failure occurs when a drain field has inadequate drainage or a "break", such that

effluent flows directly to the soil surface, bypassing travel through the soil profile. In this

situation, the effluent is either available to be washed into waterways during runoff

events or is directly deposited in-stream due to proximity. A survey of septic pump-out

contractors, previously performed by MapTech, showed that failures were more likely to

occur in the winter-spring months than in the summer-fall months, and that a higher

percentage of system failures were reported because of a back-up to the household than

because of a failure noticed in the yard.

MapTech previously sampled waste from septic tank pump-outs and found an average

fecal coliform density of 1,040,000 cfu/100 mL (MapTech, 199a). An average fecal

coliform density for human waste of 13,000,000 cfu/g and a total waste load of 75

gal/day/person was reported by Geldreich (1978).



Table 3.3 Human population, housing units, houses on sanitary sewer, septic systems, and other sewage disposal systems for areas contributing to impaired segments in the Powell River study area.

Impaired Segment Population Housing Units

Sanitary Sewer

Septic Systems Other *

Butcher Fork VAS-P18R_BUH01A04 845 394 39 340 15

S.F. Powell River VAS-P18R_PLL02A00 550 201 0 187 14

North Fork Powell River VAS-P20R_PWL01A00 4,193 2,308 1,020 1,144 144

Wallen Creek VAS-P22R_WAL01A00 1,146 524 26 456 42

Upper Powell River VAS-P17R_POW01A94 5,065 2,591 1,740 766 85

Middle Powell River VAS-P19R_POW03A00 16,303 7,804 3,985 3,568 251

Lower Powell River VAS-P21R_POW02A02 23,928 11,864 5,313 6,079 472

* Houses with sewage disposal systems other than sanitary sewer and septic systems. The figures for the Lower Powell River are totals for the entire watershed.

3.2.2 Biosolids

Biosolids were applied within the Powell River study area (Table 3.4). The total amount

of biosolids applied was 543 tons. The task of regulating biosolids application in

Virginia was transferred in 2007 from the Virginia Department of Health to the Virginia

Department of Environmental Quality. Biosolids are required to be spread according to

sound agronomic requirements with consideration for topography and hydrology. Class

B biosolids may not have a fecal coliform density greater than 1,995,262 cfu/g (total

solids). Application rates must be limited to a maximum of 15 dry tons/acre per three-

year period.



Table 3.4 Application of biosolids within the Powell River study area (2000 – 2008).

Impairment Tons Lower Powell River VAS-P19R_POW03A00 579

Middle Powell River VAS-P21R_POW02A02 579

Total 579* *Total is not the summation of tons in both impairments since both entries refer to the same amount which impacts both impairments.

3.2.3 Pets

Among pets, cats and dogs are the predominant contributors of fecal coliform in the

Powell River watershed and were the only pets considered in this analysis. Cat and dog

populations were derived from American Veterinary Medical Association Center for

Information Management demographics in 1997. Dog waste load was reported by

Weiskel et al. (1996), while cat waste load was previously measured by MapTech. Fecal

coliform density for dogs and cats was previously measured from samples collected by

MapTech. A summary of the data collected is given in Table 3.5. Table 3.6 lists the

domestic animal populations for impairments in the Powell River study area.

Table 3.5 Domestic animal population density, waste load, and fecal coliform density.

Type Population Density Waste load FC Density (an/house) (g/an-day) (cfu/g)

Dog 0.534 450 480,000 Cat 0.598 19.4 9



Table 3.6 Estimated domestic animal populations in areas contributing to impaired segments in the Powell River study area.

Impaired Segment Dogs Cats

Butcher Fork VAS-P18R_BUH01A04 211 236

S.F. Powell River VAS-P18R_PLL02A00 108 121

North Fork Powell River VAS-P20R_PWL01A00 1,235 1,385

Wallen Creek VAS-P22R_WAL01A00 224 251

Upper Powell River VAS-P17R_POW01A94 1,386 1,551

Middle Powell River VAS-P19R_POW03A00 4,196 4,697

Lower Powell River VAS-P21R_POW02A02 6,592 7,381

The figures for the Lower Powell River are totals for the entire watershed including other impairment.

3.2.4 Livestock

The predominant type of livestock in the Powell River study area is beef cattle, although

most types of livestock identified were considered in modeling the watersheds. Table 3.7

gives a summary of livestock populations in the Powell River study area, organized by

impairment. Animal populations were based on communication with VADEQ, Virginia

Cooperative Extension Service (VCE), Virginia Department of Conservation and

Recreation (VADCR), Natural Resources Conservation Service (NRCS, 2008a), Daniel

Boone Soil and Water Conservation District (DBSWCD), Lonesome Pine Soil and Water

Conservation District (LPSWCD), watershed visits, and verbal communication with

citizens at the first public meeting.



Table 3.7 Livestock populations in areas contributing to impaired segments in the Powell River study area.

Impaired Segment Beef Beef Calf

Dairy Milker

Dairy Replace

Dairy Calf Swine Horse Sheep

Butcher Fork VAS-P18R_BUH01A04 110 105 0 0 0 1 37 3

S.F. Powell River VAS-P18R_PLL02A00 62 60 0 0 0 0 21 1

North Fork Powell River VAS-P20R_PWL01A00 168 245 0 0 0 1 16 3

Wallen Creek VAS-P22R_WAL01A00 455 1015 0 0 0 6 98 7

Upper Powell River VAS-P17R_POW01A94 6 5 0 0 0 0 2 0

Middle Powell River VAS-P19R_POW03A00 740 1142 60 30 30 5 208 15

Lower Powell River VAS-P21R_POW02A02 2,164 4,181 60 30 30 21 493 38

The figures for the Lower Powell River are totals for the entire watershed including other impairment. Values of fecal coliform density of livestock sources were based on sampling previously

performed by MapTech (MapTech, 1999a). Reported manure production rates for

livestock were taken from American Society of Agricultural Engineers (ASAE, 1998). A

summary of fecal coliform density values and manure production rates is presented in

Table 3.8.

Table 3.8 Average fecal coliform densities and waste loads associated with livestock.

Waste Load Fecal Coliform Density

Waste Storage Die-off factor Type

(lb/d/an) (cfu/g) Beef stocker (850 lb) 51.0 101,000 NA

Beef calf (350 lb) 21.0 101,000 NA Dairy milker (1,400 lb) 120.4 271,329 0.5

Dairy heifer (850 lb) 70.0 271,329 0.25 Dairy calf (350 lb) 29.0 271,329 0.5

Hog (135 lb) 11.3 400,000 0.8 Horse (1,000 lb) 51.0 94,000 NA

Sheep (60 lb) 2.4 43,000 NA 1units are cfu/100ml

Fecal coliform produced by livestock can enter surface waters through four pathways.

First, waste produced by animals in confinement is typically collected, stored, and

applied to the landscape (e.g., pasture and cropland), where it is available for wash-off



during a runoff-producing rainfall event. Table 3.9 shows the average percentage of

collected livestock waste that is applied throughout the year. Second, grazing livestock

deposit manure directly on the land where it is available for wash-off during a runoff-

producing rainfall event. Third, livestock with access to streams occasionally deposit

manure directly in streams. Fourth, some animal confinement facilities may have

drainage systems that divert wash-water and waste directly to drainage ways or streams.

Table 3.9 Average percentage of collected livestock waste applied throughout year.

Applied % of Total Land use Month Dairy Beef January 2.00 4.00 Cropland

February 2.00 4.00 Cropland March 20.00 12.00 Cropland April 20.00 12.00 Cropland May 5.00 12.00 Cropland June 2.00 8.00 Pasture July 2.00 8.00 Pasture

August 2.00 8.00 Pasture September 21.00 12.00 Cropland

October 20.00 12.00 Cropland November 2.00 4.00 Cropland December 2.00 4.00 Cropland

Some livestock were expected to deposit a portion of waste on land areas. The

percentage of time spent on pasture for dairy and beef cattle was estimated based on

projects in other areas of southwest Virginia. Horses, sheep, and hogs were assumed to

be in pasture 100% of the time.

It was assumed that beef cattle were expected to make a significant contribution through

direct deposition with access to flowing water. For areas where direct deposition by

cattle is assumed, the average amount of time spent by dairy and beef cattle in stream

access areas for each month is given in Tables 3.10 and 3.11.



Table 3.10 Average time dry cows and replacement heifers spend in different areas per day.

Pasture Stream Access Loafing Lot Month (hr) (hr) (hr) January 23.3 0.7 0

February 23.3 0.7 0 March 22.6 1.4 0 April 21.8 2.2 0 May 21.8 2.2 0 June 21.1 2.9 0 July 21.1 2.9 0

August 21.1 2.9 0 September 21.8 2.2 0

October 22.6 1.4 0 November 22.6 1.4 0 December 23.3 0.7 0

Table 3.11 Average time beef cows not confined in feedlots spend in pasture and stream access areas per day.

Pasture Stream Access Month (hr) (hr) January 23.3 0.7

February 23.3 0.7 March 23.0 1.0 April 22.6 1.4 May 22.6 1.4 June 22.3 1.7 July 22.3 1.7

August 22.3 1.7 September 22.6 1.4

October 23.0 1.0 November 23.0 1.0 December 23.3 0.7

3.2.5 Wildlife

The predominant wildlife species in the Powell River watershed were determined through

consultation with wildlife biologists from the Virginia Department of Game and Inland

Fisheries (VDGIF), United States Fish and Wildlife Service (FWS), citizens from the

watershed, and source sampling. Population densities were calculated from data

provided by VDGIF and FWS, and are listed in Table 3.12 (Bidrowski, 2004; Farrar,



2003; Fies, 2004; Knox, 2004; Norman, 2004; Raftovich, 2004; Rose and Cranford,

1987).

Table 3.12 Wildlife population densities for the Powell River study area. Deer Turkey Goose Duck Muskrat Raccoon Beaver

(an/ac of habitat)

(an/ac of habitat)

(an/ac of habitat)

(an/ac of habitat)

(an/ac of habitat)

(an/ac of habitat)

(an/mi of stream)

0.0279 0.0087 0.0189 0.0333 0.6115 0.0226 0.25

The numbers of animals estimated to be in the Powell River watershed are reported in

Table 3.13. Habitat and seasonal food preferences were determined based on information

obtained from The Fire Effects Information System (USDA, 1999) and VDGIF

(Costanzo, 2003; Norman, 2003; Rose and Cranford, 1987; and VDGIF, 1999). Waste

loads were comprised from literature values and discussion with VDGIF personnel

(ASAE, 1998; Bidrowski, 2003; Costanzo, 2003; Weiskel et al., 1996, and Yagow,

1999).

Table 3.13 Estimated wildlife populations in the Powell River study area. Impaired Segment Deer Duck Goose Raccoon Turkey Beaver Muskrat

Butcher Fork VAS-P18R_BUH01A04 54 116 92 96 16 38 838

S.F. Powell River VAS-P18R_PLL02A00 86 192 152 149 26 67 1,381

North Fork Powell River VAS-P20R_PWL01A00 392 687 544 683 115 255 4,948

Wallen Creek VAS-P22R_WAL01A00 404 885 700 701 122 188 6,372

Upper Powell River VAS-P17R_POW01A94 422 969 767 736 127 303 6,978

Middle Powell River VAS-P19R_POW03A00 963 2,032 1,609 1,687 284 552 14,636

Lower Powell River VAS-P21R_POW02A02 2,030 4,131 3,270 3,543 598 1,154 29,756

The fecal coliform density of beaver waste was taken from sampling done for the

Mountain Run TMDL development (Yagow, 1999). Percentage of time spent in stream

access areas and percentage of waste directly deposited to streams was based on habitat

information and location of feces during source sampling. Fecal coliform densities and



estimated percentages of time spent in stream access areas (i.e., within 100 feet of

stream) are reported in Table 3.14.

Table 3.14 Average fecal coliform densities and percentage of time spent in stream access areas for wildlife.

Animal Type Fecal Coliform Density

Portion of Day in Stream Access Areas

(cfu/g) (%) Raccoon 2,100,000 5 Muskrat 1,900,000 90 Beaver 1,000 100 Deer 380,000 5

Turkey 1,332 5 Goose 250,000 50 Duck 3,500 75

Table 3.15 summarizes the habitat and fecal production information that was obtained.

Where available, fecal coliform densities were based on sampling of wildlife scat

performed by MapTech. The only value that was not obtained from MapTech sampling

in the watershed was for beaver.



Table 3.15 Wildlife fecal production rates and habitat. Animal Waste Load Habitat

(g/an-day)

Raccoon 450

Primary = region within 600 ft of perennial streams Secondary = region between 601 and 7,920 ft from perennial streams Infrequent/Seldom = rest of watershed area including waterbodies (lakes, ponds)

Muskrat 100

Primary = waterbodies, and land area within 66 ft from the edge of perennial streams, and waterbodies Secondary = region between 67 and 308 ft from perennial streams, and waterbodies Infrequent/Seldom = rest of the watershed area

Beaver1 200 Primary = Perennial streams. Generally flat slope regions (slow moving water), food sources nearby (corn, forest, younger trees) Infrequent/Seldom = rest of the watershed area

Deer 772

Primary = forested, harvested forest land, orchards, grazed woodland, urban grassland, cropland, pasture, wetlands, transitional land Secondary = low density residential, medium density residential Infrequent/Seldom = remaining land use areas

Turkey2 320

Primary = forested, harvested forest land, grazed woodland, orchards, wetlands, transitional land Secondary = cropland, pasture Infrequent/Seldom = remaining land use areas

Goose3 225


Mallard (Duck) 150


1 Beaver waste load was calculated as twice that of muskrat, based on field observations. 2 Waste load for domestic turkey (ASAE, 1998). 3 Goose waste load was calculated as 50% greater than that of duck, based on field observations and conversation with Gary Costanzo (Costanzo, 2003)


MODELING PROCEDURE 4-1

4. MODELING PROCEDURE: LINKING THE SOURCES TO THE ENDPOINT

Establishing the relationship between in-stream water quality and the source loadings is a

critical component of TMDL development. It allows for the evaluation of management

options that will achieve the desired water quality endpoint. In the development of

TMDLs in the Powell River study area, the relationship was defined through computer

modeling based on data collected throughout the watersheds. Monitored flow and water

quality data were then used to verify that the relationships developed through modeling

were accurate. There are five basic steps in the development and use of a water quality

model: model selection, source assessment, selection of a representative modeling period,

model calibration, model validation, and model simulation.

Model selection involves identifying an approved model that is capable of simulating the

pollutants of interest with the available data. Source assessment involves identifying and

quantifying the potential sources of pollutants in the watershed. Selection of a

representative period involves the identification of a time period that accounts for critical

conditions associated with all potential sources within the watershed. Calibration is the

process of comparing modeled data to observed data and making appropriate adjustments

to model parameters to minimize the error between observed and simulated events.

Validation is the process of comparing modeled data to observed data during a period

other than that used for calibration, with the intent of assessing the capability of the

model in hydrologic conditions other than those used during calibration. During

validation, no adjustments are made to model parameters. Once a suitable model is

constructed, the model is then used to predict the effects of current loadings and potential

management practices on water quality.

4.1 Modeling Framework Selection

The USGS Hydrologic Simulation Program - Fortran (HSPF) water quality model was

selected as the modeling framework to simulate streamflow, overland runoff and to

perform TMDL allocations.



The HSPF model simulates a watershed by dividing it up into a network of stream

segments (referred to in the model as RCHRES), impervious land areas (IMPLND) and

pervious land areas (PERLND). Each subwatershed contains a single RCHRES, modeled

as an open channel, and numerous PERLNDs and IMPLNDs, representing the various

land uses in that subwatershed. Water and pollutants from the land segments in a given

subwatershed flow into the RCHRES in that subwatershed. Point discharges and

withdrawals of water and pollutants are simulated as flowing directly to or withdrawing

from a particular RCHRES as well. Water and pollutants from a given RCHRES flow

into the next downstream RCHRES. The network of RCHRESs is constructed to mirror

the configuration of the stream segments found in the physical world. Therefore,

activities simulated in one impaired stream segment affect the water quality downstream

in the model.

The HSPF model is a continuous simulation model that can account for nonpoint source

(NPS) pollutants in runoff, as well as pollutants entering the flow channel from point

sources. In establishing the existing and allocation conditions, seasonal variations in

hydrology, climatic conditions, and watershed activities were explicitly accounted for in

the model. The use of HSPF allowed consideration of seasonal aspects of precipitation

patterns within the watershed.

4.2 Model Setup

Daily precipitation data was available within the watershed at the Big Stone Gap NCDC

Coop station #440735. Missing values were filled using daily precipitation from the

Wise 3E NCDC Coop station #449215. The final filled daily precipitation was

disaggregated using the hourly station data.

4.2.1 Subwatersheds

To adequately represent the spatial variation in the watershed, the Powell River and

Tributaries drainage area was divided into forty four (44) subwatersheds (Figure 4.1).

The rationale for choosing these subwatersheds was based on the availability of water

quality data, the stream network configuration, and the limitations of the HSPF model.

Thirty-seven of these subwatersheds were used in hydrologic calibration since they were



upstream of the flow gage with observed data (outlet of subwatershed 13). The entire set

of 44 subwatersheds was used in the bacteria calibration.

Figure 4.1 shows all subwatersheds, which were used to achieve the unified model.

Table 4.1 notes the subwatersheds contained within each impairment, the impaired

stream segments, and the outlet subwatershed for each impairment.

Figure 4.1 All subwatersheds delineated for modeling in the Powell River

study area.



Table 4.1 Impairments and subwatersheds within the Powell River study area.

Impairment Impaired Subwatershed(s) Outlet Contributing Subwatersheds

Butcher Fork VAS-BUH01A04 34 34 33,34

S.F. Powell River VAS-PLL02A00 28,29 29 27,28,29

Upper Powell River VAS-POW01A94 5 5 1,2,3,4,5,35,36,37,44,45

Middle Powell River VAS-POW03A00 9,10 10 1,2,3,4,5,6,7,8,9,10,27,28,29,30,31,3

2,33,34,35,36,37,44,45,69 N.F. Powell River VAS-PWL01A00 55,56 56 46,47,48,49,50,55,56, 58,59

Wallen Creek VAS-WAL01A00 24 24 18,19,21,23,24,25

Lower Powell River VAS-POW02A02 13,14 14

1,2,3,4,5,6,7,8,9,10,11,12,13,14,18,19,21,23,24,25,26,27,28,29,30,31,

32,33,34,35,36,37,44,45,46,47,48, 49,50,55,56,58,59,69

In an effort to standardize modeling procedures across the state, VADEQ has required

that fecal bacteria models be run at a 1-hour time-step. The HSPF model requires that the

time of concentration in any subwatershed be greater than the time-step being used for

the model. These modeling constraints as well as the desire to maintain a spatial

distribution of watershed characteristics and associated parameters were considered in the

delineation of subwatersheds. The spatial division of the watersheds allowed for a more

refined representation of pollutant sources, and a more realistic description of hydrologic

factors in the watersheds.

4.2.2 Land uses

Ten land uses were identified in the watershed. These land uses were obtained by

merging different sources including the MRLC land use grid, active mining layers

provided by the Virginia Department of Mines, Minerals, and Energy (DMME),

topographic maps (for delineating abandoned mine lands), and aerial photography of the

region. The 10 land use types are given in Table 4.2. Within each subwatershed, up to

the ten land use types were represented. Each land use in each subwatershed has

hydrologic parameters (e.g., average slope length) and pollutant behavior parameters

(e.g., E. coli accumulation rate) associated with it. These land use types are represented



in HSPF as pervious land segments (PERLNDs) and impervious land segments

(IMPLNDs). Impervious areas in the watershed are represented in four IMPLND types,

while there are ten PERLND types, each with parameters describing a particular land use.

Some IMPLND and PERLND parameters (e.g., slope length) vary with the particular

subwatershed in which they are located. Others vary with the season (e.g., upper zone

storage) to account for plant growth, die-off, and removal.

Figure 4.2 shows the land uses used in modeling the Powell River study area. Table 4.3

shows the breakdown of land uses within the drainage area of each impairment. These

acreages represent only what is within the boundaries of the Powell River study area.

Table 4.2 Consolidated land use categories for the Powell River drainage area used in HSPF modeling.

TMDL Land use Categories

Pervious / Impervious (%)

Abandoned Mine Land Pervious (75%)

Impervious (25%)

Active Mining Pervious (75%)

Impervious (25%) Barren Pervious (100%) Cropland Pervious (100%)

Commercial Pervious (40%)

Impervious (60%) Forest Pervious (100%) Livestock Access Pervious (100%) Pasture Pervious (100%)

Residential Pervious (80%)

Impervious (20%) Water Pervious (100%)



Figure 4.2 Land uses in the Powell River study area watershed.

MO

DELIN

G PR

OC

EDU

RE

4-7

TMD

L Developm

ent

Powell R


Table 4.3 Spatial distribution of land use types in acres in the Powell River study area.

Impaired Segment Open Water AML Active

Mining Residential Forest Commercial Barren Pasture/ Hay Cropland LAX Total

Acres Butcher Fork VAS-BUH01A04 6 51 0 566 3,545 132 97 955 31 42 5,426

S.F. Powell River VAS-PLL02A00 86 0 0 211 7,192 1 7 848 7 37 8,389

Upper Powell River VAS-POW01A94 120 8,564 7,673 2,349 34,278 425 10 56 8 0 53,483

Middle Powell River VAS-POW03A00 250 8,644 7,673 7,570 69,642 1,105 449 9,441 190 222 105,185

Lower Powell River VAS-POW02A02 477 10,409 8,214 14,990 134,144 1,572 705 30,325 277 972 202,085

N.F. Powell River VAS-PWL 01A00 124 1,746 541 3,333 31,391 287 115 2,419 0 62 40,017

Wallen Creek VAS-WAL01A00 85 0 0 1,432 19,645 16 58 8,698 5 537 30,475


4-8 MODELING PROCEDURE

Die-off of fecal bacteria can be handled implicitly or explicitly. For land-applied fecal

matter (mechanically applied and deposited directly), die-off was addressed implicitly

through monitoring and modeling. Samples of collected waste prior to land application

(i.e., dairy waste from loafing areas) were collected and analyzed by MapTech.

Therefore, die-off is implicitly accounted for through the sample analysis. Die-off

occurring in the field was represented implicitly through model parameters such as the

maximum accumulation and the 90% wash off rate, which were adjusted during the

calibration of the model. These parameters were assumed to represent not only the

delivery mechanisms, but the bacteria die-off as well. Once the fecal bacteria entered the

stream, the general decay module of HSPF was incorporated, thereby explicitly

addressing the die-off rate. The general decay module uses a first order decay function to

simulate die-off.

4.3 Stream Characteristics

HSPF requires that each stream reach be represented by constant characteristics (e.g.,

stream geometry and resistance to flow). This data are entered into HSPF via the

Hydraulic Function Tables (F-tables). The F-tables developed consist of four columns:

depth (ft), area (ac), volume (ac-ft), and discharge (ft3/s). The depth represents the

possible range of flow, with a maximum value beyond what would be expected for the

reach. The area listed is the surface area of the flow in acres. The volume corresponds to

the total volume in the reach, and is reported in acre-feet. The discharge is simply the

stream outflow, in cubic feet per second.

In order to develop the entries for the F-tables, a combination of the NRCS Regional

Hydraulic Geometry Curves (NRCS, 2008b), Digital Elevation Models (DEM), nautical

charts, and bathymetry data was used. The NRCS has developed empirical formulas for

estimating stream top width, cross-sectional area, average depth, and flow rate, at bank-

full depth as functions of the drainage area for regions of the United States. Appropriate

equations were selected based on the geographic location of the Powell River watershed.

Using these NRCS equations, an entry was developed in the F-table that represented a

bank-full situation for the streams at each subwatershed outlet. A profile perpendicular to

the channel was generated showing the stream profile height with distance for each



subwatershed outlet (Figure 4.3). Consecutive entries to the F-table are generated by

estimating the volume of water and surface area in the reach at incremental depths taken

from the profile.

Figure 4.3 Stream profile representation in HSPF.

Conveyance was used to facilitate the calculation of discharge in the reach with values

for resistance to flow (Manning’s n) assigned based on recommendations by Brater and

King (1976) and shown in Table 4.4. The conveyance was calculated for each of the two

floodplains and the main channel; these figures were then added together to obtain a total

conveyance. Calculation of conveyance was performed following the procedure

described by Chow (1959). Average reach slope and reach length were obtained from

GIS layers of the watershed, which included elevation from DEMs and a stream-flow

network based on National Hydrography Dataset (NHD) data. The total conveyance was

then multiplied by the square root of the average reach slope to obtain the discharge (in

ft3/s) at a given depth. An example of an F-table used in HSPF is shown in Table 4.5.

Table 4.4 Summary of Manning's roughness coefficients for channel cells*. Section Upstream Area (ha) Manning's n

Intermittent stream 18 - 360 0.06 Perennial stream 360 and greater 0.05 *Brater and King (1976)



Table 4.5 Example of an F-table calculated for the HSPF model. Depth

(ft) Area (ac)

Volume (ac-ft)

Outflow (ft3/s)

0 0 0 0 3.28 0.71 1.41 17.07 6.56 1.89 5.15 45.23 9.84 2.54 12.18 85.02

13.12 4.77 24.80 152.82 16.40 56.55 77.51 637.72 19.68 1,047.22 1,635.10 18,846.85 22.96 2,875.31 7,405.99 69,827.77 26.24 3,495.32 18,464.40 133,806.76 29.52 4,426.89 31,720.10 160,393.97

4.4 Selection of a TMDL Critical Condition

EPA regulations at 40 CFR 130.7 (c)(1) require that TMDLs take into account critical

conditions for stream flow, loading, and water quality parameters. The intent of this

requirement is to ensure that the water quality of the Powell River study area is protected

during times when it is most vulnerable.

Critical conditions are important because they describe the factors that combine to cause

a violation of water quality standards and will help in identifying the actions that may

have to be undertaken in order to meet water quality standards. Fecal bacteria sources

within the Powell River study area are attributed to both point and nonpoint sources.

Critical conditions for waters impacted by land-based nonpoint sources generally occur

during periods of wet weather and high surface runoff. In contrast, critical conditions for

point source-dominated systems generally occur during low flow and low dilution

conditions. Point sources, in this context also, include nonpoint sources that are not

precipitation driven (e.g., fecal deposition to stream).

A description of the data used in these analyses is shown in Tables 2.1 and 2.2 in Chapter

2. Graphical analyses of fecal bacteria concentrations and flow duration intervals showed

that water quality standard violations occurred at nearly every flow interval at nine (9)

VADEQ monitoring stations in the Powell River watershed (Figures 4.4 - Figure 4.12).

This demonstrates that this stream should have all flow regimes represented in the

allocation modeling time period.



1

10

100

1,000

10,000

100,000

0 10 20 30 40 50 60 70 80 90 100Flow Duration Interval (%)

Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BPOW138.91VADEQ Instantaneous E.coli Standard (235 cfu/100mL) Observed E.coli at 6BPOW138.91

High Flow Moist Conditions Mid-Range Flow Dry Conditions Low Flow

Figure 4.4 Fecal bacteria and E.coli concentrations at 6BPOW138.91 on the Powell River versus discharge at USGS Gaging Station #03531500.

1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BPOW165.78


Figure 4.5 Fecal bacteria concentrations at 6BPOW165.78 on the Powell River versus discharge at USGS Gaging Station #03531500.



1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)




1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)






1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BPWL001.49VADEQ Instantaneous E.coli Standard (235 cfu/100mL) Observed E.coli at 6BPWL001.49


Figure 4.8 Fecal bacteria and E.coli concentrations at 6BPWL001.49 on the N.F. Powell River versus discharge at USGS Station #03531500.

1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BPWL004.10VADEQ Instantaneous E.coli Standard (235 cfu/100mL) Observed E.coli at 6BPWL004.10


Figure 4.9 Fecal bacteria and E.coli concentrations at 6BPWL004.10 on the N.F. Powell River versus discharge at USGS Station #03531500.



1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous E.coli Standard (235 cfu/100mL) Observed E.coli at 6BWAL000.12


Figure 4.10 E.coli bacteria concentrations at 6BWAL000.12 on Wallen Creek versus discharge at USGS Gaging Station #03531500.

1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BPLL006.38


Figure 4.11 Fecal bacteria concentrations at 6BPLL006.38 on the S.F. Powell River versus discharge at USGS Gaging Station #03531500.



1

10

100

1,000

10,000

100,000


Bac

teri

a C

once

ntra

tion

(cfu

/100

ml)

VADEQ Instantaneous FC Standard (400 cfu/100mL) Observed FC at 6BBUH000.76


Figure 4.12 Fecal bacteria concentrations at 6BBUH000.76 on Butcher Fork versus discharge at USGS Gaging Station #03531500.

Based on this analysis, a time period for calibration and validation of the model was

chosen based on the overall distribution of wet and dry seasons (Section 4.5) in order to

capture a wide range of hydrologic circumstances for all impaired streams in this study

area.

4.5 Selection of Representative Modeling Periods

Selection of the modeling period was based on two factors: availability of data (discharge

and water-quality) and the need to represent critical hydrological conditions. Mean daily

discharge at USGS Gaging Station 03531500 in the Powell River near Jonesville was

available from 1931 through 2008. The modeling period was selected to include the

VADEQ assessment period from July 1992 through December 2006 that led to the

inclusion of the impaired streams in this TMDL study area on the 1996, 1998, 2002,

2004, 2006 and 2008 Section 303(d) lists. Hydrologic calibration period was October

1992 to September 1996 and hydrologic validation period was October 1996 to



September 2000. The fecal concentration data from this period were evaluated to

determine the relationship between concentration and the level of flow in the stream.

High concentrations of fecal coliform were recorded in all flow regimes, thus it was

concluded that the critical hydrological condition included a wide range of wet and dry

seasons. Multiple periods were used for water quality calibration and validation

depending on the availability of monitored data.

The critical flow regime study (Section 4.4) showed that all flow regimes, but most

critically high flows, should be represented in the modeling time periods of the impaired

streams in this study. The hydrology calibration/validation/water quality calibration and

validation time period, have both the high and low daily average streamflow and

precipitation, which represent the high and low flow critical regimes (Figures 4.13 and

4.14). The figures are shown here to demonstrate the historical annual and seasonal

stream flow and precipitation and how the selected time period encompasses a

representative range of values. Table 4.6 shows the statistical comparison between

calibration/validation time periods and historic time period.



0

100

200

300

400

500

600

700

800

900

1,000

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

Water Year

Ave

rage

Dai

ly F

low

(cfs

) .

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

Ave

rage

Dai

ly P

reci

pita

tion

(in)

.

Validation Calibration Discharge (2037500) Precipitation (444101/446656/447201) Figure 4.13 Modeling time periods, annual historical flow (USGS Station

03531500), and precipitation (Station 440735/449215) data.



0

500

1,000

1,500

2,000

1988

1989

1991

1992

1994

1995

1997

1998

2000

2001

2003

2004

2006

2007

Water Year

Ave

rage

Dai

ly fl

ow (c

fs)

.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Ave

rage

Dai

ly P

reci

pita

tion(

in)

.

Validation Calibration Discharge (2037500) Precipitation (444101/446656/447201)

Figure 4.14 Modeling time periods, seasonal historical flow (USGS Station 03531500), and precipitation (Station 440735/449215) data.

Table 4.6 Comparison of modeled period to historical records for the Powell River. Discharge (03531500) Precipitation (440735/449215) Fall Winter Spring Summer Fall Winter Spring Summer Historical Record (1987 - 2008) Historical Record (1987 - 2008)

Mean 0.121 0.152 0.158 0.142 360.7 932.3 662.1 185.8 Variance 0.001 0.002 0.002 0.002 65068 148840 83737 9306

Calibration and Validation Time Periods (10/92-9/96; 10/96-9/00)

Calibration and Validation Time Periods (10/92-9/96; 10/96-9/00)

Mean 0.125 0.186 0.160 0.111 366.4 1217.4 681.5 132.4 Variance 0.001 0.002 0.002 0.002 83237 174779 77201 6811

p-values p-values Mean 0.393 0.051 0.443 0.054 0.483 0.073 0.442 0.098

Variance 0.484 0.385 0.348 0.496 0.312 0.356 0.512 0.392



4.6 Source Representation

Both point and nonpoint sources can be represented in the model. In general, point

sources are added to the model as a time-series of pollutant and flow inputs to the stream.

Land-based nonpoint sources are represented as an accumulation of pollutants on land,

where some portion is available for transport in runoff. The amount of accumulation and

availability for transport vary with land use type and season. The model allows for a

maximum accumulation to be specified. The maximum accumulation was adjusted

seasonally to account for changes in die-off rates, which are dependent on temperature

and moisture conditions. Some nonpoint sources, rather than being land-based, are

represented as being deposited directly to the stream (e.g., animal defecation in stream).

These sources are modeled similarly to point sources, as they do not require a runoff

event for delivery to the stream. These sources are primarily due to animal activity,

which varies with the time of day. Once in stream, die-off is represented by a first-order

exponential equation.

Much of the data used to develop the model inputs for modeling water quality is time-

dependent (e.g., population). Depending on the timeframe of the simulation being run,

different estimates were used. Data were obtained for the appropriate timeframe for

water quality calibration and validation. Data representing 2008 were used for the

allocation runs in order to represent current conditions.

4.6.1 Permitted Sources

Forty five (45) point sources are permitted to discharge water into surface waters in the

Powell River study area through the Virginia Pollutant Discharge Elimination System

(VPDES) (Tables 3.1 and 3.2). Section 3.1 discusses these permits in more detail. Six

(6) of these VPDES permits are permitted for fecal bacteria control. Thirty six (36) of

the permits are domestic or single family home permits that discharge less than 1,000

gallons per day. For calibration and validation condition runs, recorded flow and fecal

bacteria concentration or Total Residual Chlorine (TRC) levels documented by the

VADEQ were used as the input for each permit (Table 4.7). The TRC data was related to

fecal bacteria concentrations using a regression analysis. Table 4.7 shows the minimum

and maximum discharge rate in million gallons per day (MGD) and the minimum and



maximum fecal coliform bacteria concentration in colony forming units per 100

milliliters (cfu/100mL). These values are the sums of all the data for each outfall.

The design flow capacity was used for allocation runs. This flow rate was combined with

a fecal coliform concentration of 200 cfu per 100 ml to ensure that compliance with state

water quality standards could be met even if permitted loads were at maximum levels.

The design flow rates and fecal coliform bacteria concentrations are shown in Table 4.7.

Nonpoint sources of pollution that were not driven by runoff (e.g., direct deposition of

fecal matter to the the stream by wildlife) were modeled similarly to point sources. These

sources, as well as land-based sources, are identified in the following sections.

Table 4.7 Flow rates and bacteria loads used to model VADEQ active permits in the Powell River study area.

Calibration/Validation Allocation

Flow Rate (MGD)

Bacteria Concentration (cfu/100mL)

Flow Rate (MGD)

Bacteria Concentration(cfu/100mL)

VADEQ Permit

Number Facility Name Min Max Min Max Design

Flow

Fecal Coliform

Geometric Mean

Standard

VA0020940 Big Stone Gap Regional WWTP 0.8 3.767 0.5 743 2.0 200

VA0029599 Pennington Gap STP 0.21 0.63 4.2 5.7 0.6 200

VA0060798 Wise County Public

Schools - Appalachia E S STP

0.0 0.03 0.0 8.2 0.012 200

VA0063941 Dot Mobile Home Park STP 0.0 0.0015 2.0 4.3 0.0049 200

VA0075515 Lee County Public Service Authority -

Cross Creek 0.00 0.017 0.0 0.0 0.03 200

VA0089397 Lee County PSA -

Hickory Flats WWTP

0.10 0.52 0 192 0.80 200

VAG***** Each of 36 Domestic

Waste Treatment Plants

0.001 0.001 200 200 0.001 200



4.6.2 Private Residential Sewage Treatment

The number of septic systems in the Powell River study area was calculated by

overlaying U.S. Census Bureau data (USCB, 1990; USCB, 2000) with the subwatersheds.

During allocation runs, the number of households was projected to 2008, based on

current growth rates (USCB, 2000) resulting in 6,079 septic systems and 472 straight

pipes (Table 4.8).

Table 4.8 Estimated failing septic systems and pit privies for 2008 in the Powell River study area.

Subwatershed Septic Systems

Failing Septic Systems

Straight Pipes

Butcher Fork VAS-P18R_BUH01A04 340 76 15

S.F. Powell River VAS-P18R_PLL02A00 187 46 14

North Fork Powell River VAS-P20R_PWL01A00 1,144 521 144

Wallen Creek VAS-P22R_WAL01A00 456 77 42

Upper Powell River VAS-P17R_POW01A94 766 661 85

Middle Powell River VAS-P19R_POW03A00 3,568 1,507 251

Lower Powell River VAS-P21R_POW02A02 6,079 2,231 472

Failing septic systems were assumed to deliver all effluent to the soil surface where it

was available for wash-off during a runoff event. In accordance with estimates from

Raymond B. Reneau, Jr. from Virginia Tech, a 40% failure rate for systems designed and

installed prior to 1964, a 20% failure rate for systems designed and installed between

1964 and 1984, and a 5% failure rate on all systems designed and installed after 1984 was

used in development of the TMDLs for the Powell River study area. Total septic systems

in each category were calculated using U.S. Census Bureau block demographics. The

applicable failure rate was multiplied by each total and summed to get the total failing

septic systems per subwatershed. The fecal coliform density for septic system effluent

was multiplied by the average design load for the septic systems in the subwatershed to

determine the total load from each failing system. Additionally, the loads were



distributed seasonally based on a survey of septic pump-out contractors to account for

more frequent failures during wet months.

Straight pipes were estimated using 1990 U.S. Census Bureau block demographics.

Houses listed in the Census sewage disposal category “other means” were assumed to be

disposing sewage via straight pipes. Corresponding block data and subwatershed

boundaries were intersected to determine an estimate of uncontrolled discharges in each

subwatershed. The loadings from straight pipes were modeled in the same manner as

direct discharges to the stream.

4.6.3 Livestock

Fecal coliform produced by livestock can enter surface waters through four pathways:

land application of stored waste, deposition on land, direct deposition to streams, and

diversion of wash-water and waste directly to streams. Each of these pathways is

accounted for in the model. The amount of fecal coliform directed through each pathway

was calculated by multiplying the fecal coliform density with the amount of waste

expected through that pathway. Different livestock populations were estimated for each

water quality modeling period (calibration/validation/allocation). The numbers are based

on data provided by Virginia Agricultural Statistics (VASS), with values updated and

discussed by VADCR, NRCS and SWCDs as well as taking into account growth rates in

these counties as determined from data reported by the Virginia Agricultural Statistics

Service (VASS, 1998; VASS, 2002). For land-applied waste, the fecal coliform density

measured from stored waste was used, while the density in as-excreted manure was used

to calculate the load for deposition on land and to streams (Table 3.8). The use of fecal

coliform densities measured in stored manure accounts for any die-off that occurs in

storage. The modeling of fecal coliform entering the stream through diversion of wash-

water was accounted for by the direct deposition of fecal matter to streams by cattle.

4.6.3.1 Land Application of Collected Manure

Collection of livestock manure was assumed the case on dairy farms. The average daily

waste production per month was calculated using the number of animal units, weight of

animal, and waste production rate as reported in Section 3.2.4. For dairy cows, the only



waste assumed to be collected was from currently milking cows and calves. Second, the

total amount of waste produced in confinement was calculated based on the proportion of

time spent in confinement. Finally, values for the percentage of loafing lot waste

collected, based on data provided by SWCD representatives and local stakeholders, were

used to calculate the amount of waste available to be spread on pasture and cropland

(Table 3.9). Stored waste was spread on pasture and cropland. It was assumed that

100% of land-applied waste is available for transport in surface runoff.

4.6.3.2 Deposition on Land

For cattle, the amount of waste deposited on land per day was a proportion of the total

waste produced per day. The proportion was calculated based on the study entitled

“Modeling Cattle Stream Access” conducted by the Biological Systems Engineering

Department at Virginia Tech and MapTech, Inc. for VADCR (MapTech, 2002). The

proportion was based on the amount of time spent in pasture, but not in close proximity

to accessible streams, and was calculated as follows:

Proportion = [(24 hr) – (time in confinement) – (time in stream access areas)]/(24 hr)

All other livestock (horse, sheep, hogs) were assumed to deposit all feces on pasture. The

total amount of fecal matter deposited on the pasture land was area-weighted.

4.6.3.3 Direct Deposition to Streams

The amount of waste deposited in streams each day was a proportion of the total waste

produced per day by cattle. First, the proportion of manure deposited in “stream access”

areas was calculated based on the “Modeling Cattle Stream Access” study. The

proportion was calculated as follows:

Proportion = (time in stream access areas)/(24 hr)

For the waste produced on the “stream access” land use, 30% of the waste was modeled

as being directly deposited in the stream and 70% remained on the land segment adjacent

to the stream. The 70% remaining was treated as manure deposited on land. However,

applying it in a separate land-use area (stream access) allows the model to consider the



proximity of the deposition to the stream. The 30% that was directly deposited to the

stream was modeled in the same way that point sources are handled in the model.

4.6.4 Biosolids

Investigation of VADEQ data indicated that biosolids applications have occurred within

the Powell River study area. Class B biosolids are permitted to contain up to 1,995,262

cfu/g-dry, as compared with approximately 240 cfu/g-dry for dairy waste. Detailed

records of biosolids application location, timing and quantity were available, enabling the

water quality modeling to be carried out in an “as applied” fashion, wherein the water

quality model received land based inputs of biosolids loads on the day in which they

actually occurred. During both model runs, biosolids were modeled as having a fecal

concentration of 157,835 cfu/g, the mean value of measured biosolids concentrations

observed in several years of samples supplied by VADEQ for sources applied during

2002 to 2009. Applications were modeled as being spread onto the land surface over a

six-hour period on the date of reported application. An assumption of proper application

was made, wherein no biosolids were modeled as being spread in stream corridors.

4.6.5 Wildlife

For each species of wildlife, a GIS habitat layer was developed based on the habitat

descriptions that were obtained (Section 3.2.5). An example of one of these layers is

shown in Figure 4.15. This layer was overlaid with the land use layer and the resulting

area was calculated for each land use in each subwatershed. The number of animals per

land segment was determined by multiplying the area by the population density. Fecal

coliform loads for each land segment were calculated by multiplying the wasteload, fecal

coliform densities, and number of animals for each species.



Figure 4.15 Example of raccoon habitat layer in the Powell River study area, as developed by MapTech.

For each species, a portion of the total wasteload was considered land-based, with the

remaining portion being directly deposited to streams. The portion being deposited to

streams was based on the amount of time spent in stream access areas (Table 3.14). It

was estimated that, for all animals other than beaver, 5% of fecal matter produced while

in stream access areas was directly deposited to the stream. For beaver, it was estimated

that 100% of fecal matter would be directly deposited to streams.

4.6.6 Pets

Cats and dogs were the only pets considered in this analysis. Population density (animals

per house), wasteload, and fecal coliform density are reported in Section 3.2.3. Waste

from pets was distributed on residential land uses. The number of households per

subwatershed was taken from the 2000 Census (USCB, 1990 and USCB, 2000). The



number of animals per subwatershed was determined by multiplying the number of

households by the pet population density. The amount of fecal coliform deposited daily

by pets in each subwatershed was calculated by multiplying the wasteload, fecal coliform

density, and number of animals for both cats and dogs. The wasteload was assumed not

to vary seasonally. The populations of cats and dogs were projected from 2000 data to

2008.

4.7 Sensitivity Analysis

Sensitivity analyses are performed to determine a model’s response to changes in certain

parameters. This process involves changing a single parameter a certain percentage from

a baseline value while holding all other parameters constant. This process is repeated for

several parameters in order to gain a complete picture of the model’s behavior. The

information gained during sensitivity analysis can aid in model calibration, and it can also

help to determine the potential effects of uncertainty in parameter estimation. Sensitivity

analyses were conducted to assess the sensitivity of the model to changes in hydrologic

and water quality parameters as well as to assess the impact of unknown variability in

source allocation (e.g., seasonal and spatial variability of waste production rates for

wildlife, livestock, septic system failures, uncontrolled discharges, background loads, and

point source loads).

4.7.1 Hydrology Sensitivity Analysis

The HSPF parameters adjusted for the hydrologic sensitivity analysis are presented in

Table 4.9, with base values for the model runs given. The parameters were adjusted to -

50%, -10%, 10%, and 50% of the base value, and the model was run for water years

1993-1996. Where an increase of 50% exceeded the maximum value for the parameters,

the maximum value was used and the parameters increased over the base value were

reported. The hydrologic quantities of greatest interest in a fecal coliform model are

those that govern peak flows and low flows. Peak flows, being a function of runoff, are

important because they are directly related to the transport of fecal coliforms from the

land surface to the stream. Peak flows were most sensitive to changes in the parameters

governing infiltration such as INFILT (Infiltration), LZSN (Lower Zone Storage), and by

UZSN (Upper Zone Storage), which governs surface transport, LZETP (Lower Zone



Evapotranspiration), which affects soil moisture and AGWRC (Groundwater Recession

Rate). Low flows are important in a water quality model because they control the level

of dilution during dry periods. Parameters with the greatest influence on low flows (as

evidenced by their influence in the Low Flows and Summer Flow Volume statistics) were

AGWRC (Groundwater Recession Rate), LZETP, INFILT, UZSN, CEPSC (Interception

Storage Capacity), and LZSN. The responses of these and other hydrologic outputs are

reported in Table 4.10.

Table 4.9 HSPF base parameter values used to determine hydrologic model response.

Parameter Description Units Base Value LZSN Lower Zone Nominal Storage in 2.0 –10.0 INFILT Soil Infiltration Capacity in/hr 0.0846 – 0.2401 BASETP Base Flow Evapotranspiration --- 0.01 - 0.01 INTFW Interflow Inflow --- 2.0 - 2.0 DEEPFR Groundwater Inflow to Deep Recharge --- 0.1 - 0.1 AGWRC Groundwater Recession rate --- 0.98 KVARY Groundwater Recession Flow 1/in 1.0 MON-INTERCEP Monthly Interception Storage Capacity in 0.01-0.2 MON-UZSN Monthly Upper Zone Nominal Storage in 0.18-0.9 MON-LZETP Monthly Lower Zone Evapotranspiration in 0.01-0.8



Table 4.10 HSPF Sensitivity analysis results for hydrologic model parameters for the Powell River and Tributaries.

Percent Change In

Model Parameter

Parameter Total Flow

High Flows

Low Flows

Winter Flow

Volume

Spring Flow

Volume

Summer Flow

Volume

Fall Flow Volume

Total Storm

Volume Change (%)

AGWRC1 0.85 0.77 24.53 -35.87 -0.18 -3.29 -1.29 14.37 8.73

AGWRC1 0.92 0.54 15.11 -23.11 -0.07 -3.02 -1.87 12.44 6.75

AGWRC1 0.96 0.29 6.07 -10.81 0.44 -2.31 -1.69 7.31 2.82

AGWRC1 0.999 -16.41 -17.68 8.49 -29.72 -9.39 7.80 -15.95 -21.87

BASETP -50 0.17 -0.31 1.62 -0.23 0.56 1.33 -0.68 -0.89 BASETP -10 0.03 -0.06 0.33 -0.05 0.11 0.25 -0.13 -0.24 BASETP 10 -0.03 0.06 -0.33 0.05 -0.11 -0.25 0.12 0.23 BASETP 50 -0.16 0.31 -1.62 0.23 -0.56 -1.23 0.59 1.08 DEEPFR -50 0.38 0.26 0.53 0.38 0.32 0.44 0.46 0.39 DEEPFR -10 0.08 0.05 0.11 0.08 0.06 0.08 0.10 0.08 DEEPFR 10 -0.08 -0.05 -0.11 -0.08 -0.06 -0.07 -0.11 -0.08 DEEPFR 50 -0.38 -0.26 -0.54 -0.38 -0.32 -0.35 -0.56 -0.39 INFILT -50 1.93 17.93 -14.54 3.96 -0.07 -1.07 2.99 4.38 INFILT -10 0.25 2.49 -2.25 0.66 -0.06 -0.40 0.35 0.61 INFILT 10 -0.21 -2.19 2.02 -0.59 0.05 0.47 -0.32 -0.48 INFILT 50 -0.76 -8.69 8.28 -2.49 0.37 2.35 -1.13 -1.94 INTFW -50 0.02 0.99 -0.20 0.05 -0.06 0.08 0.01 0.02 INTFW -10 0.00 0.15 -0.03 0.01 -0.01 0.01 0.00 0.00 INTFW 10 0.00 -0.13 0.03 -0.01 0.01 -0.01 0.00 0.00 INTFW 50 -0.01 -0.56 0.11 -0.03 0.03 -0.04 0.00 -0.01 LZSN -50 5.22 12.26 -11.15 11.24 5.76 -8.64 0.75 8.46 LZSN -10 0.92 1.74 -1.11 1.78 0.79 -0.62 0.18 1.26 LZSN 10 -0.90 -1.55 0.67 -1.64 -0.77 0.99 -0.99 -1.20 LZSN 50 -4.65 -6.83 2.91 -8.58 -3.61 3.21 -3.21 -5.36

CEPSC -50 1.19 -1.03 6.79 -1.03 4.13 5.62 -2.78 -1.90 CEPSC -10 0.23 -0.19 1.32 -0.17 0.68 1.10 -0.41 -0.44 CEPSC 10 -0.21 0.18 -1.19 0.16 -0.60 -0.93 0.24 0.25 CEPSC 50 -0.87 0.72 -4.81 0.81 -2.68 -4.14 1.20 1.51 LZETP -50 15.02 13.10 28.38 10.06 5.10 22.35 42.58 14.19 LZETP -10 1.65 1.20 3.87 1.15 0.33 2.46 5.01 1.62 LZETP 10 -1.40 -1.02 -3.25 -0.99 -0.29 -1.75 -4.54 -1.34 LZETP 50 -9.97 -7.82 -20.19 -8.44 -2.03 -11.61 -29.09 -9.10

KVARY -50 -0.28 -3.59 9.85 -3.01 3.38 3.81 -3.75 -3.01 KVARY -10 -0.04 -0.62 1.47 -0.35 0.47 0.50 -0.70 -0.52 KVARY 10 0.04 0.58 -1.32 0.28 -0.40 -0.42 0.67 0.30 KVARY 50 0.14 2.64 -5.50 0.91 -1.51 -1.56 3.03 1.38 UZSN -50 3.59 10.55 -4.20 2.70 3.51 6.49 3.29 4.27 UZSN -10 0.54 1.66 -0.68 0.51 0.35 0.84 0.69 0.64 UZSN 10 -0.49 -1.54 0.66 -0.49 -0.29 -0.53 -0.87 -0.68 UZSN 50 -2.09 -6.42 3.16 -2.39 -0.86 -1.98 -3.80 -2.79

1Actual parameter value used



4.7.2 Water Quality Parameter Sensitivity Analysis

For the water quality sensitivity analysis, an initial base run was performed using

precipitation data from water years 1993 through 1996, and model parameters established

for 2008 conditions (see section 4.5 for a complete explanation of selected model time

periods). The three HSPF parameters impacting the model’s water quality response

(Table 4.11) were increased and decreased by amounts that were consistent with the

range of values for the parameter. The First Order Decay (FSTDEC) was the parameters

with the greatest influence on monthly geometric mean concentration (Table 4.12). The

reason behind the more pronounced impact of change in decay rate on concentration of

bacteria in the stream is that changes in decay rate impact bacteria from nonpoint as well

as point sources and direct-nonpoint sources. On the other hand, changes in maximum

fecal coliform accumulation on the land (MON-SQOLIM) and wash-off rate for fecal

coliform on land surface (WSQOP) only impact the nonpoint portion of the bacteria.

Graphical depictions of the results of this sensitivity analysis can be seen in Figures 4.16

through 4.18.

Table 4.11 Base parameter values used to determine water quality model response.

Parameter Description Units Base Value MON-SQOLIM Maximum FC Accumulation on Land FC/ac 0 – 8.0E+11 WSQOP Wash-off Rate for FC on Land Surface in/hr 1 FSTDEC In-stream First Order Decay Rate 1/day 1

MO

DELIN

G PR

OC

EDU

RE

4-30

TMD

L Developm

ent

Powell R


Table 4.12 Percent change in average monthly fecal coliform mean for the years 1993-1996. Model Parameter

Change Percent Change in Average Monthly E. coli Geometric Mean for 1993-1996

Parameter (%) Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec FSTDEC -50 14.94 14.54 15.13 15.31 15.17 14.98 15.74 15.39 15.25 15.86 15.24 15.51 FSTDEC -10 2.53 2.47 2.57 2.59 2.57 2.54 2.67 2.59 2.61 2.66 2.58 2.58 FSTDEC 10 -2.39 -2.33 -2.42 -2.44 -2.42 -2.39 -2.51 -2.43 -2.46 -2.50 -2.43 -2.42 FSTDEC 50 -10.81 -10.57 -10.94 -11.03 -10.97 -10.80 -11.34 -10.97 -11.18 -11.26 -10.98 -10.89 SQOLIM -50 -7.17 -7.73 -5.32 -7.50 -7.89 -4.95 -5.46 -3.82 -4.26 -8.53 -13.08 -9.25 SQOLIM -25 -3.02 -3.19 -2.08 -3.07 -3.30 -2.01 -2.25 -1.60 -1.82 -3.96 -6.28 -4.18 SQOLIM 25 2.12 2.12 1.29 2.03 2.35 1.53 1.78 1.31 1.40 3.31 5.51 3.24 SQOLIM 50 4.05 4.01 2.39 3.67 4.13 2.72 3.19 2.37 2.54 6.22 10.56 6.17 WSQOP -50 8.20 8.60 8.08 9.66 9.20 6.43 4.79 4.20 3.50 10.27 11.97 8.85 WSQOP -10 1.12 1.29 1.12 1.43 1.28 0.83 0.66 0.56 0.45 1.39 1.74 1.33 WSQOP 10 -0.98 -1.16 -0.98 -1.27 -1.12 -0.71 -0.58 -0.48 -0.39 -1.20 -1.55 -1.19 WSQOP 50 -4.04 -4.86 -3.97 -5.19 -4.54 -2.77 -2.32 -1.91 -1.50 -4.71 -6.33 -4.93

MO

DELIN

G PR

OC

EDU

RE

4-31

TMD

L Developm

ent

Powell R


-50

-40

-30

-20

-10

0

10

20

30

40

50

Oct-92 Feb-93 Jun-93 Oct-93 Feb-94 Jun-94 Oct-94 Feb-95 Jun-95 Oct-95 Feb-96 Jun-96 Oct-96

Perc

ent C

hang

e in

Geo

met

ric M

ean

-50% -10% +10% +50%

Figure 4.16 Results of sensitivity analysis on monthly mean concentrations as affected by changes in the in-stream first-order decay rate (FSTDEC).

MO

DELIN

G PR

OC

EDU

RE

4-32

TMD

L Developm

ent

Powell R


-50

-40

-30

-20

-10

0

10

20

30

40

50


Perc

ent C

hang

e in

Geo

met

ric

Mea

n

-50% -25% +25% +100%

Figure 4.17 Results of sensitivity analysis on monthly mean concentrations as affected by changes in maximum fecal accumulation on land (MON-SQOLIM).

MO

DELIN

G PR

OC

EDU

RE

4-33

TMD

L Developm

ent

Powell R


-50

-40

-30

-20

-10

0

10

20

30

40

50


Perc

ent C

hang

e in

Geo

met

ric

Mea

n

-50% -10% +10% +50%

Figure 4.18 Results of sensitivity analysis on monthly mean concentrations as affected by changes in the wash-off rate from land surfaces (WSQOP).



In addition to analyzing the sensitivity of the model response to changes in water quality

transport and die-off parameters, the response of the model to changes in land-based and

direct loads was also analyzed. It is evident in Figure 4.19 that the model predicts a

linear relationship between increased fecal coliform concentrations in both land and

direct applications, and total load reaching the stream. The magnitude of this relationship

differs between land applied and direct loadings; a 100% increase in the land applied

loads results in an increase of about 60% in stream loads, while a 100% increase in direct

loads results in approximately a 30% increase in stream loads. Both direct loads and land

applied loads have a significant impact on the geometric mean concentrations (Figures

4.20 and 4.21).

-100.0

-80.0

-60.0

-40.0

-20.0

0.0

20.0

40.0

60.0

80.0

100.0

Percent Change in Input

Perc

ent C

hang

e in

Res

pons

e

Land Applications Direct Deposits

Figure 4.19 Results of total loading sensitivity analysis for outlet of the Powell River and Tributaries study area.

MO

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4-35

TMD

L Developm

ent

Powell R


-100

-80

-60

-40

-20

0

20

40

60

80

100


Perc

ent C

hang

e in

Mon

thly

Ave

rage

s

+100% +10% -10% -100%

Figure 4.20 Results of sensitivity analysis on monthly geometric-mean concentrations in the Powell River and Tributaries study area, as affected by changes in land-based loadings.

TMD

L Developm

ent

Powell R


4-36

MO

DELIN

G PR

OC

EDU

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-80

-60

-40

-20

0

20

40

60

80

100


Perc

ent C

hang

e in

Mon

thly

Ave

rage

s

+100% +10% -10% -100%

Figure 4.21 Results of sensitivity analysis on monthly geometric-mean concentrations in the Powell River and Tributaries study area, as affected by changes in loadings from direct nonpoint sources.



4.8 Model Calibration and Validation Processes

Calibration and validation are performed in order to ensure that the model accurately

represents the hydrologic and water quality processes in the watershed. The model’s

hydrologic parameters were set based on available soils, land use, and topographic data.

Through calibration, these parameters were adjusted within appropriate ranges until the

model performance was deemed acceptable.

4.8.1 HSPF - Hydrologic Calibration and Validation

The model calibrated for hydrologic accuracy using daily flow data for the period October

1992 through September 1996. The modeled output from subwatershed 13 was compared

against the Powell River USGS Gaging Station #03531500 data

HSPF parameters that were adjusted during the hydrologic calibration represented: the

amount of evapotranspiration from the root zone (LZETP), the recession rates for

groundwater (AGWRC) and interflow (IRC), the amount of soil moisture storage in the

upper zone (UZSN) and lower zone (LZSN), the amount of interception storage (CEPSC),

the infiltration capacity (INFILT), the amount of soil water contributing to interflow

(INTFW), deep groundwater inflow fraction (DEEPER), baseflow PET (BASETP),

groundwater recession flow (KVARY), and active groundwater storage PET (AGWETP).

Table 4.13 contains the possible range for the above parameters along with the initial

estimate and final calibrated value. State variables in the PERLND water (PWAT) section of

the User’s Control Input (UCI) file were adjusted to reflect initial conditions.



Table 4.13 Initial hydrologic parameters estimated for the Powell River TMDL study area, and resulting final values after calibration.

Parameter Units Possible Range of Parameter

Value

Initial Parameter Estimate

Final Calibrated Parameter

Value LZSN in 2.0 – 15.0 0.4 – 2 1 – 5 INFILT in/hr 0.001 – 0.50 0.04 – 0.12 0.028 – 0.084 KVARY 1/in 0.0 – 5.0 1 0 AGWRC 1/day 0.85 – 0.999 0.985 0.975 DEEPFR --- 0.0 – 0.50 0.30 0.40 BASETP --- 0.0 – 0.20 0 – 0.05 0.0 – 0.02 AGWETP --- 0.0 – 0.20 0 0 INTFW --- 1.0 – 10.0 1.0 1.5 IRC 1/day 0.30 – 0.85 0.3 0.5 MON-INTERCEPT in 0.01 – 0.40 0.01 – 0.30 0.01 – 0.2

MON-UZSN in 0.05 – 2.0 0.18 – 1.8 0.11 – 1.08 MON-LZETP --- 0.1 – 0.9 0.01 – 0.64 0.01 – 0.8

* Represents a multiplier; + represents an addition Table 4.14 shows the percent difference (or error) between observed and modeled data for

total in-stream flows, upper 10% flows, and lower 50% flows during model calibration.

These values represent a close agreement with the observed data, indicating the model was

well calibrated. Figures 4.22 and 4.23 graphically show these comparisons.

Table 4.14 Hydrology calibration model performance from 10/1/1992 through 9/30/1996 at USGS Gaging Station #03531500 on the Powell River and Tributaries (subwatershed 13).

Criterion Observed Modeled Error Total In-stream Flow: 517.13 470.98 -8.92%

Upper 10% Flow Values: 235.49 242.41 2.94% Lower 50% Flow Values: 55.54 55.42 -0.21%

Winter Flow Volume 273.01 224.18 -17.89% Spring Flow Volume 131.42 115.16 -12.38%

Summer Flow Volume 39.98 46.88 17.25% Fall Flow Volume 72.72 84.77 16.56%

Total Storm Volume 473.25 433.55 -8.39% Winter Storm Volume 262.13 214.89 -18.02% Spring Storm Volume 120.45 105.79 -12.17%

Summer Storm Volume 29.03 37.58 29.43% Fall Storm Volume 61.64 75.30 22.15%

MO

DELIN

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4-39

TMD

L Developm

ent Pow


A

Observed vs. Modeled (10/1/1992-9/30/1996)

1

10

100

1000

10000

100000

0 10 20 30 40 50 60 70 80 90 100

Exceedence Percentage

Flow

(cfs

)

ObservedModeled

Figure 4.22 Powell River modeled flow duration versus USGS Gaging Station #03531500 data from 10/1/1992 to 9/30/1996 (subwatershed 13).

MO

DELIN

G PR

OC

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4-40 TMD

L Developm

ent Pow


A


10

100

1000

10000

10000010

/01/

1992

11/1

3/19

9212

/26/

1992

02/0

7/19

9303

/22/

1993

05/0

4/19

93

06/1

6/19

9307

/29/

1993

09/1

0/19

93

10/2

3/19

9312

/05/

1993

01/1

7/19

94

03/0

1/19

9404

/13/

1994

05/2

6/19

9407

/08/

1994

08/2

0/19

94

10/0

2/19

9411

/14/

1994

12/2

7/19

94

02/0

8/19

9503

/23/

1995

05/0

5/19

95

06/1

7/19

9507

/30/

1995

09/1

1/19

95

10/2

4/19

9512

/06/

1995

01/1

8/19

96

03/0

1/19

9604

/13/

1996

05/2

6/19

96

07/0

8/19

9608

/20/

1996

Date

Flow

(cfs

)

0

1

2

3

4

5

6

7

8

9

10

Prec

ipita

tion

(in.)

Observed Precip Modeled

Figure 4.23 Powell River modeled results versus USGS Gaging Station #03531500 data from 10/1/1992 to 9/30/1996 (subwatershed 13).



The modeled output was validated for the period of 10/1996 to 9/2000. Simulated flow at

subwatershed 13 was compared with daily observed flow at the Powell River USGS

Gaging Station #03531500. Table 4.15 shows the percent difference (or error) between

observed and modeled data for total in-stream flows, upper 10% flows, and lower 50%

flows during model calibration. These values represent a close agreement with the

observed data, indicating the model was well calibrated and has been validated during a

different time period. Figures 4.24 and 4.25 graphically show these comparisons.

Table 4.15 Hydrology validation model performance from 10/1/1996 through 9/30/2000 at USGS Gaging Station #03531500 on the Powell River (subwatershed 13).

Criterion Observed Modeled Error Total In-stream Flow: 373.60 386.77 3.53%

Upper 10% Flow Values: 164.96 188.94 14.54% Lower 50% Flow Values: 36.44 38.85 6.62%

Winter Flow Volume 168.36 180.79 7.38% Spring Flow Volume 126.40 113.42 -10.27%

Summer Flow Volume 22.10 19.91 -9.90% Fall Flow Volume 56.74 72.65 28.04%

Total Storm Volume 341.39 361.55 5.90% Winter Storm Volume 160.40 174.53 8.81% Spring Storm Volume 118.36 107.11 -9.51%

Summer Storm Volume 14.00 13.63 -2.71% Fall Storm Volume 48.62 66.27 36.30%

MO

DELIN

G PR

OC

EDU

RE

4-42 TMD

L Developm

ent

Powell R



1

10

100

1000

10000

100000

0 10 20 30 40 50 60 70 80 90 100

Exceedence Percentage

Flow

(cfs

)

ObservedModeled

Figure 4.24 Powell River modeled flow duration versus USGS Gaging Station #03531500 data for validation (subwatershed 13).

MO

DELIN

G PR

OC

EDU

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4-43

TMD

L Developm

ent Pow


A


10

100

1000

10000

10000010

/01/

1996

11/1

3/19

96

12/2

6/19

96

02/0

7/19

97

03/2

2/19

97

05/0

4/19

97

06/1

6/19

97

07/2

9/19

97

09/1

0/19

97

10/2

3/19

97

12/0

5/19

97

01/1

7/19

98

03/0

1/19

98

04/1

3/19

98

05/2

6/19

98

07/0

8/19

98

08/2

0/19

98

10/0

2/19

98

11/1

4/19

98

12/2

7/19

98

02/0

8/19

99

03/2

3/19

99

05/0

5/19

99

06/1

7/19

99

07/3

0/19

99

09/1

1/19

99

10/2

4/19

99

12/0

6/19

99

01/1

8/20

00

03/0

1/20

00

04/1

3/20

00

05/2

6/20

00

07/0

8/20

00

08/2

0/20

00

Date

Flow

(cfs

)

0

1

2

3

4

5

6

7

8

9

10

Prec

ipita

tion

(in.)

Observed Precip Modeled

Figure 4.25 Powell River validation modeled results versus USGS Gaging Station #03531500 data from (subwatershed 13).



4.8.2 HSPF – E. coli Water Quality Calibration

Water quality calibration is complicated by a number of factors; first, water quality (E.

coli) concentrations are highly dependent on flow conditions. Any variability associated

with the modeling of stream flow compounds the variability in modeling water quality

parameters. Second, the concentration of E. coli is particularly variable. Variability in

location and timing of fecal deposition, variability in the density of bacteria in feces

(among species and for an individual animal), environmental impacts on re-growth and

die-off, and variability in delivery to the stream all lead to difficulty in measuring and

modeling E. coli concentrations. Additionally, the VADEQ data were censored at

specific high and low values (e.g. 8,000 cfu/100ml or 16,000 cfu/100ml as highs or 100

cfu/100ml as low value). Limited amount of measured data for use in calibration and the

practice of censoring both high and low concentrations impede the calibration process.

Four parameters were utilized for model adjustment: in-stream first-order decay rate

(FSTDEC), monthly maximum accumulation on land (MON-SQOLIM), the rate of

surface runoff that will remove 90% of stored fecal bacteria per hour (WSQOP), and the

temperature correction coefficient for first-order decay of quality (THFST). All of these

parameters were initially set at expected levels for the watershed conditions and adjusted

within reasonable limits until an acceptable match between measured and modeled

bacteria concentrations was established. Depending on the type of available bacteria

data, either fecal coliform and E.coli monitored data were used. Table 4.16 shows the

model parameters utilized in calibration with their typical ranges, initial estimates, and

final calibrated values. Table 4.17 shows the time period, the subwatershed which the

station is located, and bacteria type used for each monitoring station used in the

calibration.



Table 4.16 Model parameters utilized for water quality calibration.

Parameter Units Typical Range Initial Parameter Estimate

Calibrated Parameter Value

MON-SQOLIM FC/ac 1.0E-02 – 1.0E+30 0.0 – 1.2E+11 0.0 – 2.6E+11 WSQOP in/hr 0.05 – 3.00 0.0 – 2.80 0.12 – 2.80 FSTDEC 1/day 0.01 – 10.00 1.0 0.2 – 10 THFST none 1.0 – 2.0 1.07 1.0 - 1.07

Table 4.17 Bacteria calibration periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area.

Stream Calibration Period Subwatershed Type of Bacteria Used

6BPOW193.38 10/1/2000 - 9/30/2003 2 Fecal Coliform 6BPOW179.20 10/1/2000 - 9/30/2003 5 Fecal Coliform 6BPOW165.78 10/1/2000 - 9/30/2003 9 Fecal Coliform 6BPOW138.91 10/1/2000 - 9/30/2003 14 Fecal Coliform 6BBUH000.76 10/1/2000 - 9/30/2003 34 Fecal Coliform 6BPLL004.24 10/1/2000 - 9/30/2003 30 Fecal Coliform 6BPLL000.27 10/1/2000 - 9/30/2003 31 Fecal Coliform 6BPWL001.49 10/1/1997 - 9/30/2000 55 Fecal Coliform 6BWAL000.12 10/1/2002 - 9/30/2004 24 E.coli

Figures 4.26 through 4.34 show the results of water quality calibration. Monitored values

are an instantaneous snapshot of the bacteria level, whereas the modeled values are daily

averages based on hourly modeling. The monitored values may have been sampled at the

highest concentration of the day and thus correctly appear above the modeled daily

average. Although the range of modeled daily average values may not reach every

instantaneous monitored value, the modeled data follows the trend of monitored data, and

typically includes the monitored extremes. The highest peaks in the simulated

concentrations are generally the result of sewer overflows and there may not have been a

monitored observation on the given overflow days.

Careful inspection of graphical comparisons between continuous simulation results and

limited observed points was the primary tool used to guide the calibration process. Table

4.18 shows the predicted and observed values for the maximum value, geometric mean,

and single sample (SS) instantaneous violations for the Powell River stream segments.



10

100

1,000

10,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed

Figure 4.26 Fecal coliform calibration for 10/1/2000 to 9/30/2003 for VADEQ station 6BPOW193.38 in subwatershed 2 on the Powell River.

10

100

1,000

10,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed




10

100

1,000

10,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed


10

100

1,000

10,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed




10

100

1,000

10,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed

Figure 4.30 Fecal coliform calibration for 10/1/2000 to 9/30/2003 for VADEQ station 6BBUH000.76 in subwatershed 34 on Butcher Fork.

10

100

1,000

10,000

100,000

10/1/2001 1/9/2002 4/19/2002 7/28/2002 11/5/2002 2/13/2003 5/24/2003 9/1/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed

Figure 4.31 Fecal coliform calibration for 10/1/2001 to 9/30/2003 for VADEQ station 6BPLL004.24 in subwatershed 30 on S.F. Powell River.



10

100

1,000

10,000

100,000

10/1/2000 4/19/2001 11/5/2001 5/24/2002 12/10/2002 6/28/2003

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed

Figure 4.32 Fecal coliform calibration for 10/1/2001 to 9/30/2003 for VADEQ station 6BPLL000.27 in subwatershed 31 on S.F. Powell River.

10

100

1,000

10,000

10/1/1997 4/19/1998 11/5/1998 5/24/1999 12/10/1999 6/27/2000

Date

Fec

al C

olif

orm

(cfu

/100

ml)

modeled observed

Figure 4.33 Fecal coliform calibration for 10/1/1997 to 9/30/2000 for VADEQ station 6BPWL001.49 in subwatershed 55 on N.F. Powell River.



10

100

1,000

10,000

10/1/2002 1/9/2003 4/19/2003 7/28/2003 11/5/2003 2/13/2004 5/23/2004 8/31/2004

Date

E.c

oli

(cfu

/100

ml)

modeled observed

Figure 4.34 E. coli calibration for 10/1/2002 to 9/30/2004 for VADEQ station 6BWAL000.12 in subwatershed 24 on Wallen Creek.

TMD

L Developm

ent

Powell R


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DELIN

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4-51

Table 4.18 Monitored and simulated maximum value, geometric mean, and single sample violation percentage for the calibration period.

Maximum Value (cfu/100ml)

Geometric Mean (cfu/100ml)

SS % violations 1

Station Subwatershed Monitored Simulated Monitored Simulated Monitored Simulated

6BPOW193.38 2 3,800 1,983.6 610.51 485.14 75.00 72.05 6BPOW179.20 5 4,100 2,512.1 184.92 287.76 16.67 31.69 6BPOW165.78 9 700 4,416.2 143.57 194.95 11.11 10.95 6BPOW138.91 14 400 5,590.1 125.24 192.18 5.26 10.95 6BBUH000.76 34 3,900 3,985.6 358.4 465.23 46.15 57.03 6BPLL004.24 30 600 12,659.9 221.62 319.79 30.77 32.21 6BPLL000.27 31 4,700 17,971.6 191.03 437.83 23.08 48.72 6BPWL001.49 55 1,500 1,377.55 145.19 307.10 26.67 11.68 6BWAL000.12 24 480 1,875.4 82.88 122.51 16.67 21.07

1 SS = single sample instantaneous standard violations (>235 cfu/100mL for E.coli and >400 cfu/100mL for fecal coliform)



4.8.3 HSPF – Bacteria Water Quality Validation

Bacteria water quality model validation was performed on stations shown in Table 4.19.

Figures 4.35 through 4.44 show the results of water quality validation. Table 4.20 shows

the predicted and observed values for the maximum value, geometric mean, and single

sample (SS) instantaneous violations for the Powell River stream segments.

Table 4.19 Bacteria validation periods, subwatersheds containing stations, and type of bacteria used in the Powell River study area.

Stream Calibration Period Subwatershed Type of Bacteria Used

6BPOW193.38 10/1/2006 – 1/31/2008 2 E.coli 6BPOW179.20 10/1/1997 – 9/30/2000 5 Fecal coliform 6BPOW165.78 10/1/1997 – 9/30/2000 9 Fecal coliform 6BPOW138.91 10/1/1997 – 9/30/2000 14 Fecal coliform 6BBUH000.76 10/1/2006 – 1/31/2008 34 E.coli 6BPLL006.38 10/1/1997 – 9/30/2000 29 Fecal coliform 6BPLL004.24 10/1/2006 – 1/31/2008 30 E.coli 6BPLL000.27 10/1/2006 – 1/31/2008 31 E.coli 6BPWL006.59 10/1/2002 – 9/30/2005 55 E.coli 6BWAL000.12 10/1/2004 – 9/30/2005 24 E.coli



10

100

1,000

10,000

10/1/2006 1/9/2007 4/19/2007 7/28/2007 11/5/2007 2/13/2008 5/23/2008 8/31/2008

Date

E.c

oli

(cfu

/100

ml)

modeled observed

Figure 4.35 E. coli validation for 10/1/12006 to 9/30/2008 for VADEQ station 6BPOW193.38 in subwatershed 2 on the Powell River.

10

100

1,000

10,000

10/1/1997 4/19/1998 11/5/1998 5/24/1999 12/10/1999 6/27/2000

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed Figure 4.36 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ

station 6BPOW179.20 in subwatershed 5 on the Powell River.



10

100

1,000

10,000

10/1/1997 4/19/1998 11/5/1998 5/24/1999 12/10/1999 6/27/2000

Date

Feca

l Col

iform

(cfu

/100

ml)


station 6BPOW165.78 in subwatershed 9 on the Powell River.

10

100

1,000

10,000

10/1/1997 4/19/1998 11/5/1998 5/24/1999 12/10/1999 6/27/2000

Date

Feca

l Col

iform

(cfu

/100

ml)

modeled observed

Figure 4.38 Fecal coliform validation for 10/1/1997 to 9/30/2000 for VADEQ station 6BPOW138.91 in subwatershed 14 on the Powell River.



10

100

1,000

10,000

10/1/2006 1/9/2007 4/19/2007 7/28/2007 11/5/2007 2/13/2008 5/23/2008 8/31/2008

Date

E.c

oli

(cfu

/100

ml)

modeled observed Figure 4.39 E.coli validation for 10/1/2006 to 9/30/2008 for VADEQ station

6BBUH000.76 in subwatershed 34 on Butcher Fork.

10

100

1,000

10,000

100,000

10/1/1997 4/19/1998 11/5/1998 5/24/1999 12/10/1999 6/27/2000

Date

Feca

l Col

iform

(cfu

/100

ml)


station 6BPLL006.38 in subwatershed 29 on S.F. Powell River.



10

100

1,000

10,000

100,000

10/1/2006 1/9/2007 4/19/2007 7/28/2007 11/5/2007 2/13/2008 5/23/2008 8/31/2008

Date

E.c

oli

(cfu

/100

ml)


6BPLL004.24 in subwatershed 30 on S.F. Powell River.

10

100

1,000

10,000

10/1/2006 1/9/2007 4/19/2007 7/28/2007 11/5/2007 2/13/2008 5/23/2008 8/31/2008

Date

E.c

oli

(cfu

/100

ml)


6BPLL000.76 in subwatershed 34 on S.F. Powell River.



10

100

1,000

10/1/2002 4/19/2003 11/5/2003 5/23/2004 12/9/2004 6/27/2005

Date

E.c

oli

(cfu

/100

ml)

modeled observed

Figure 4.43 E.coli validation for 10/1/2002 to 9/30/2005 for VADEQ station 6BPWL006.59 in subwatershed 50 on N.F. Powell River.

10

100

1,000

10,000

10/1/2004 11/20/2004 1/9/2005 2/28/2005 4/19/2005 6/8/2005 7/28/2005 9/16/2005

Date

E.c

oli

(cfu

/100

ml)

modeled observed

Figure 4.44 E.coli validation for 10/1/2004 to 9/30/2005 for VADEQ station 6BWAL000.12 in subwatershed 24 on N.F. Powell River.

TMD

L Developm

ent

Powell R


4-58

MO

DELIN

G PR

OC

EDU

RE

Table 4.20 Monitored and simulated maximum value, geometric mean, and single sample violation percentage for the validation period.

Maximum Value (cfu/100ml)

SS % violations 1

Geometric Mean (cfu/100ml) Station Subwatershed Monitored Simulated Monitored Simulated Monitored Simulated

6BPOW193.38 2 580 638.7 85.71% 83.37% 261.84 313.93 6BPOW179.20 5 6,000 3,953.3 37.50% 33.61% 208.66 270.03 6BPOW165.78 9 2,300 7,588.4 11.76% 15.60% 88.08 209.27 6BPOW138.91 14 500 4,425.3 7.14% 12.86% 54.34 214.47 6BBUH000.76 34 300 4,178.6 50.00% 52.05% 56.98 297.17 6BPLL006.38 29 5,200 5,792.2 41.18% 24.64% 141.34 218.27 6BPLL004.24 30 300 42,014 50.00% 40.16% 94.30 227.40 6BPLL000.27 31 620 113,910 14.29% 47.75% 125.93 298.26 6BPWL006.59 55 300 246 8.33% 0.09% 64.03 61.87 6BWAL000.12 24 420 1,545.3 40.00% 31.78% 109.51 121.58

1 SS = single sample instantaneous standard violations (>235 cfu/100mL for E.coli and >400 cfu/100mL for fecal coliform)


BACTERIAL ALLOCATION 5-1

5. BACTERIAL ALLOCATION

Total Maximum Daily Loads (TMDLs) consist of waste load allocations (WLAs,

permitted sources) and load allocations (LAs, non-permitted sources) including natural

background levels. Additionally, the TMDL must include a margin of safety (MOS) that

either implicitly or explicitly accounts for the uncertainties in the process (e.g., accuracy

of wildlife populations). The definition is typically denoted by the expression:

TMDL = WLAs + LAs + MOS

The TMDL becomes the amount of a pollutant that can be assimilated by the receiving

waterbody and still achieve water quality standards. For these bacterial impairments, the

TMDLs are expressed in terms of colony forming units (or resulting concentration).

Allocation scenarios were modeled using the HSPF model. Scenarios were created by

reducing direct and land-based bacteria until the water quality standards were attained.

The TMDLs developed for the impairments in the Powell River and Tributaries study

area were based on the E. coli riverine Virginia State standards. As detailed in Section

2.1, the VADEQ riverine primary contact recreational use E. coli standards state that the

calendar month geometric-mean concentration shall not exceed 126 cfu/100 mL.

According to the guidelines put forth by the VADEQ (VADEQ, 2003b) for modeling

bacteria with HSPF, the model was set up to estimate loads of fecal coliform, then the

model output was converted to concentrations of E. coli through the use of the following

equation (developed from a data set containing 493 paired data points):

)(log91905.00172.0)(log 22 fcec CC ⋅+−=

where Cec is the concentration of E. coli in cfu/100 mL and Cfc is the concentration of

fecal coliform in cfu/100 mL.

Pollutant concentrations were modeled over the entire duration of a representative

modeling period and pollutant loads were adjusted until the standards were met. The

development of the allocation scenarios was an iterative process that required numerous



runs with each followed by an assessment of source reduction against the applicable

water quality standards.

5.1 Margin of Safety (MOS)

In order to account for uncertainty in modeled output, a Margin of Safety (MOS) was

incorporated into the TMDL development process. Individual errors in model inputs,

such as data used for developing model parameters or data used for calibration, may

affect the load allocations in a positive or a negative way. A MOS can be incorporated

implicitly in the model through the use of conservative estimates of model parameters, or

explicitly as an additional load reduction requirement. The intention of an MOS in the

development of a bacteria TMDL is to ensure that the modeled loads do not

underestimate the actual loadings that exist in the watershed. An implicit MOS was used

in the development of these TMDLs. By adopting an implicit MOS in estimating the

loads in the watershed, it is ensured that the recommended reductions will in fact succeed

in meeting the water quality standard. Examples of the implicit MOS used in the

development of these TMDLs are:

• Allocating permitted point sources at the maximum allowable fecal coliform concentration, and

• Selecting a modeling period that represented the critical hydrologic conditions in the watershed. The allocation period contains both high and low flow conditions and therefore, maximizes the chance for high bacteria concentrations coming from both land-based sources and point (and direct nonpoint) sources.

5.2 Waste Load Allocations (WLAs)

There are 45 point sources currently permitted to discharge into the Powell River study

area. The allocation for the sources permitted for E. coli control is equivalent to their

current permit levels (design discharge and 126 cfu/100 ml). Future growth in each

watershed was accounted for by setting aside 1% of the TMDL for growth in permitted

discharges or creation of new ones.

5.3 Load Allocations (LAs)

Load allocations to nonpoint sources are divided into land-based loadings from land uses

(nonpoint source, NPS) and directly applied loads in the stream (livestock, wildlife,



straight pipes, and sewer overflows). Source reductions include those that are affected by

both high and low flow conditions. Land-based NPS loads most significantly impact

bacteria concentrations during high-flow conditions, while direct deposition NPS most

significantly impact low flow bacteria concentrations. The BST results confirmed the

presence of human, livestock, pet, and wildlife contamination in all impairments.

Nonpoint source load reductions were performed by land use, as opposed to reducing

sources, as it is considered that the majority of BMPs will be implemented by land use.

Appendix A shows tables of the breakdown of the annual fecal coliform per animal per

land use for contributing subwatersheds to each impairment.

5.4 Final Total Maximum Daily Loads (TMDLs)

Allocation scenarios were run sequentially, beginning with headwater impairments, and

then continuing with downstream impairments until all impairments were allocated to 0%

exceedances of all applicable standards. The first table in each of the following sections

represents the scenarios developed to determine the TMDLs. The first scenario was run

for all impairments simultaneously; subsequent runs were made after upstream

impairments were allocated. Scenario 1 in each table describes a baseline scenario that

corresponds to the existing conditions in the watershed.

Reduction scenarios exploring the role of anthropogenic sources in standards violations

were explored first to determine the feasibility of meeting standards without wildlife

reductions. In each table, a scenario reflects the impact of eliminating direct human

sources from straight pipes and sewer overflows. Further scenarios in each table explore

a range of management scenarios, leading to the final allocation scenario that contains the

predicted reductions needed to meet 0% exceedance of all applicable water quality

standards. The graphs in the following sections depict the existing and allocated 30-day

geometric mean in-stream bacteria concentrations.

The second table in each of the following sections shows the existing and allocated E.

coli loads that are output from the HSPF model. The third table shows the final in-stream

allocated loads for the appropriate bacteria species. These values are output from the

HSPF model and incorporate in-stream die-off and other hydrological and environmental



processes involved during runoff and stream routing techniques within the HSPF model

framework. The final table is an estimation of the in-stream daily load of bacteria.

The tables and graphs in the following sections all depict values at the corresponding

impairment outlet. The impairment outlet is the mouth of the impaired segment as the

segments are described in Section 1.3. It is the point at which the impaired stream flows

out of the most downstream subwatershed or segment. The impairment outlets are shown

in the “Outlet” column of Table 4.1.

5.4.1 Upper Powell River (VAS-P17R_POW01A94)

The Upper Powell River impairment receives outflow from Callahan Creek, which has

previously had a bacteria TMDL developed. Table 5.1 shows allocation scenarios used

to determine the final TMDL for the Upper Powell River impairment (VAS-

P17R_POW01A94). Because Virginia’s standard does not permit any exceedances,

modeling was conducted for a target value of 0% exceedance of the VADEQ riverine

primary contact recreational use (swimming) 30-day geometric mean standard. The

existing condition, Scenario 1, shows 11.5% violations of the geometric mean standard.

Scenario 2 was simulated with an allocated outflow from Callahan Creek (previously

conducted TMDL). Scenario 3 showed that eliminating straight pipes and unpermitted

sewer overflows would benefit water quality and allows the Upper Powell River to have a

0% violation rate of the GM swimming use standard.

An appropriate Stage I scenario would be a 50% reduction in both the straight pipe

bacteria load and the unpermitted sewer overflow load.

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Table 5.1 Allocation scenarios for reducing current bacteria loads in Upper Powell River (VAS-P17R_POW01A94)

(subwatershed 1, 2, 3, 4, 5, 35, 36, 37, 44, 45, and Callahan Creek). Percent Reductions to Existing Bacteria Loads

Wildlife Land Based Agricultural

Land Based Human Direct

Human Direct

Human and Pet Land Based

VADEQ E. coli

Standard percent

violations

Scenario Wildlife Direct

Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture,

LAX

Straight Pipes

Sewer Overflows Residential >126 GM

1 (existing) 0 0 0 0 0 0 0 11.5

2 (with

allocated Callahan Creek)

0 0 0 0 0 0 0 10.6

31 0 0 0 0 100 100 0 0.00 1Final TMDL Scenario



Figure 5.1 shows the existing and allocated monthly geometric mean E. coli

concentrations, from the Upper Powell River impairment outlet (subwatershed 5). The

graph shows existing conditions in blue, with allocated conditions overlaid in black.

1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)

Existing Allocated Geometric Mean Standard (126 cfu/100mL) _

Figure 5.1 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 5, Upper Powell River impairment outlet.

Table 5.2 contains estimates of existing and allocated in-stream E. coli loads at the Upper

Powell River impairment outlet reported as average annual cfu per year. The estimates in

Table 5.2 are generated from available data, and these values are specific to the

impairment outlet for the allocation rainfall for the current land use distribution in the

watershed. The percent reductions needed to meet zero percent violations of the 126

cfu/100mL geometric mean standard are given in the final column.

Tables A.1, A.2, and A.3 in Appendix A include the monthly land-based fecal coliform

load distribution, the monthly direct nonpoint source fecal coliform load by



subwatershed, and the annual direct deposition load by impairment, respectively. The

tables offer more details for specific implementation development and source assessment

evaluation.

Table 5.2 Estimated existing and allocated E. coli in-stream loads in the Upper Powell River impairment.

Source Total Annual Loading for

Existing Run1

Total Annual Loading for

Allocation Run1

Percent Reduction

(cfu/yr) (cfu/yr) Land Based

Active 6.67E+11 6.67E+11 0.0% AML 4.70E+11 4.70E+11 0.0% Barren 1.27E+11 1.27E+11 0.0% Comm 1.51E+12 1.51E+12 0.0% Cropland 3.86E+07 3.86E+07 0.0% Forest 2.67E+13 2.67E+13 0.0% LAX 0.00E+00 0.00E+00 0.0% Pasture 3.36E+11 3.36E+11 0.0% Residential 2.31E+13 2.31E+13 0.0%

Direct Human 5.86E+14 0.00E+00 100.0% Livestock 3.62E+11 3.62E+11 0.0% Wildlife 2.95E+13 2.95E+13 0.0% Permitted Sources 4.39E+12 4.39E+12 0%

Total Loads 6.73E+14 8.72E+13 79.4%

Table 5.3 shows the average annual TMDL, which gives the average amount of bacteria

that can be present in the stream in a given year, and still meet the water quality standard.

These values are output from the HSPF model and incorporate in-stream die-off and

other hydrological and environmental processes involved during runoff and stream

routing techniques within the HSPF model framework. To account for future growth of

urban and residential human populations, one percent of the final TMDL was set aside

for future growth in the WLA portion. The future load in the Upper Powell River

impairment was further increased to account for the proposed wastewater treatment plant

near Norton, Virginia with a design flow of 2 MGD.



Table 5.3 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Upper Powell River impairment.

Impairment WLA1 LA MOS TMDL

Upper Powell River 4.39E+12 8.28E+13 8.72E+13

VA0060798 2.09E+10 VAG400383 1.74E+09 VAG400392 1.74E+09 VAG400505 1.74E+09 VAG400089 1.74E+09 VAG400517 1.74E+09 VAG400135 1.74E+09 VAG400640 1.74E+09 VAG400715 1.74E+09 Future Load 4.36E+12

Implicit

1 The WLA reflects an allocation for potential future permits issued for bacteria control. Any issued permit will include bacteria effluent limits in accordance with applicable permit guidance and will ensure that the discharge meets the applicable numeric water quality criteria for bacteria at the end-of-pipe.

Starting in 2007, the USEPA has mandated that TMDL studies include a daily load as

well as the average annual load previously shown. The approach to developing a daily

maximum load was similar to the USEPA approved approach to developing load duration

bacterial TMDLs. The daily average in-stream loads for the Upper Powell River are

shown in Table 5.4. The daily TMDL was calculated using the 99th percentile daily flow

condition during the allocation time period at the numeric water quality criterion of 235

cfu/100ml. This calculation of the daily TMDL does not account for varying stream flow

conditions.



Table 5.4 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in the Upper Powell River impairment.

Impairment WLA1 LA MOS TMDL2 Upper Powell

River

POW01A94 1.20E+10 1.20E+13 1.20E+13VA0060798 5.73E+07 VAG400383 4.77E+06 VAG400392 4.77E+06 VAG400505 4.77E+06 VAG400089 4.77E+06 VAG400517 4.77E+06 VAG400135 4.77E+06 VAG400640 4.77E+06 VAG400715 4.77E+06 Future Load 1.19E+10

Implicit

1 The WLA reflects an allocation for potential future permits issued for bacteria control. Any issued permit will include bacteria effluent limits in accordance with applicable permit guidance and will ensure that the discharge meets the applicable numeric water quality criteria for bacteria at the end-of-pipe. 2 The TMDL is presented for the 99th percentile daily flow condition at the numeric water quality criterion of 235 cfu/100ml. The TMDL is variable depending on flow conditions. The numeric water quality criterion will be used to assess progress toward TMDL goals.


The S.F. Powell River impairment is one of the headwaters impairments in this report and

does not receive inflow from other impairments. Table 5.5 shows allocation scenarios

used to determine the final TMDL for S.F. Powell River. The existing condition,

Scenario 1, shows 15.7% violations of the geometric mean standard. Although the

existing conditions had violations, Scenario 2 (eliminating illicit residential discharges or

straight pipes and sewer overflows) allows S.F. Powell River to have a 0% violation rate

of the GM swimming use standard. An appropriate Stage I scenario would be a 50%

reduction in both the straight pipe bacteria load and the unpermitted sewer overflow load.

BA

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Table 5.5 Allocation scenarios for reducing current bacteria loads in S.F. Powell River (subwatershed 27, 28, 29). Percent Reductions to Existing Bacteria Loads



Human Direct


VADEQ E. coli

Standard percent

violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture,

LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 15.71

21 0 0 0 0 100 100 0 0 1Final TMDL Scenario




concentrations, from the S.F. Powell River impairment outlet. The graph shows existing

conditions in blue, with allocated conditions overlaid in black.

1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)


Figure 5.2 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 29, S.F. Powell River impairment outlet.

Table 5.6 contains estimates of existing and allocated in-stream E. coli loads at the S.F.




watershed. The percent reductions needed to meet zero percent violations of all

applicable water quality standards are given in the final column.







evaluation.

Table 5.6 Estimated existing and allocated E. coli in-stream loads in the S.F. Powell River impairment.


Existing Run1


Allocation Run1

Percent Reduction


Active 0.00E+00 0.00E+00 0.0% AML 0.00E+00 0.00E+00 0.0% Barren 1.12E+10 1.12E+10 0.0% Commercial 2.13E+10 2.13E+10 0.0% Cropland 6.23E+09 6.23E+09 0.0% Forest 2.43E+12 2.43E+12 0.0% LAX 1.03E+11 1.03E+11 0.0% Pasture 2.22E+12 2.22E+12 0.0% Residential 1.07E+12 1.07E+12 0.0%


Total Loads 3.84E+13 1.06E+13 82.4%


that can be present in the stream in a given year, and still meet existing water quality

standards. These values are output from the HSPF model and incorporate in-stream die-

off and other hydrological and environmental processes involved during runoff and

stream routing techniques within the HSPF model framework. To account for future

growth of urban and residential human populations, one percent of the final TMDL was

set aside for future growth in the WLA portion.



Table 5.7 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the S.F. Powell River impairment.


S.F. Powell River

1.08E+11 1.05E+13 1.06E+13

VAG400711 1.74E+09 Future Load 1.06E+11

Implicit





bacterial TMDLs. The daily average in-stream loads for S.F. Powell River are shown in

Table 5.8. The daily TMDL was calculated using the 99th percentile daily flow condition

during the allocation time period at the numeric water quality criterion of 235 cfu/100ml.

This calculation of the daily TMDL does not account for varying stream flow conditions.

Table 5.8 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in the S.F. Powell River impairment.

Impairment WLA1 LA MOS TMDL2

S.F. Powell River

2.95E+08 2.03E+12 2.03E+12

VAG400711 4.77E+06 Future Load 2.91E+08

Implicit


5.4.3 Butcher Fork (VAS-P18R_BUH01A04)

The Butcher Fork impairment is one of the headwaters impairments in this report and

does not receive inflow from other impairments. Table 5.9 shows allocation scenarios

used to determine the final TMDL for Butcher Fork. The existing condition, Scenario 1,



shows 65.2% violations of the geometric mean standard. Eliminating illicit residential

discharges or straight pipes and sewer overflows (Scenario 2) had a considerable impact

on the percentage violations. Additional reductions were however needed to meet the

standard. Eliminating livestock direct deposition in the stream as indicated by Scenario 3

allows Butcher Fork to have a 0% violation rate of the GM swimming use standard. An

appropriate Stage I scenario would be implementing Scenario 2 by eliminating illicit

discharge of human sources and sewer overflows.

ALLO

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5-15

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Table 5.9 Allocation scenarios for reducing current bacteria loads in Butcher Fork (subwatershed 33,34). Percent Reductions to Existing Bacteria Loads



Human Direct


VADEQ E. coli

Standard percent

violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture,

LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 65.2

2 0 0 0 0 100 100 0 2.7 31 0 0 100 0 100 100 0 0

1Final TMDL Scenario




concentrations, from Butcher Fork impairment outlet. The graph shows existing


1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli C

once

ntra

tion

(cfu

/100

ml)


Figure 5.3 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 34, Butcher Fork impairment outlet.

Table 5.10 contains estimates of existing and allocated in-stream E. coli loads at Butcher

Fork impairment outlet reported as average annual cfu per year. The estimates in Table

5.10 are generated from available data, and these values are specific to the impairment

outlet for the allocation rainfall for the current land use distribution in the watershed. The

percent reductions needed to meet zero percent violations of all applicable water quality

standards are given in the final column.







evaluation.

Table 5.10 Estimated existing and allocated E. coli in-stream loads in Butcher Fork impairment.


Existing Run1


Allocation Run1

Percent Reduction




Total Loads 7.48E+13 2.85E+13 71.9%










Table 5.11 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in Butcher Fork impairment.


Butcher Fork 3.08E+11 2.82E+13 2.85E+13VAG400227 1.74E+09 VAG400016 1.74E+09 VAG400373 1.74E+09 VAG400166 1.74E+09 VAG400275 1.74E+09 VAG400228 1.74E+09 VAG400128 1.74E+09 VAG400462 1.74E+09 VAG400389 1.74E+09 VAG400601 1.74E+09 VAG400642 1.74E+09 VAG400355 1.74E+09 VAG400429 1.74E+09 Future Load 2.85E+11

Implicit





bacterial TMDLs. The daily average in-stream loads for Butcher Fork are shown in

Table 5.12. The daily TMDL was calculated using the 99th percentile daily flow



conditions.



Table 5.12 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Butcher Fork impairment.


Butcher Fork 8.44E+08 1.24E+12 1.24E+12 VAG400227 4.77E+06 VAG400016 4.77E+06 VAG400373 4.77E+06 VAG400166 4.77E+06 VAG400275 4.77E+06 VAG400228 4.77E+06 VAG400128 4.77E+06 VAG400462 4.77E+06 VAG400389 4.77E+06 VAG400601 4.77E+06 VAG400642 4.77E+06 VAG400355 4.77E+06 VAG400429 4.77E+06 Future Load 7.82E+08

Implicit


5.4.4 North Fork Powell River (VAS-P20R_PWL01A00)

The N.F. Powell River impairment receives outflow from Straight Creek which has had a

bacteria TMDL developed previously. Table 5.13 shows allocation scenarios used to

determine the final TMDL for N.F. Powell River. The existing condition, Scenario 1,

shows 75.7% violations of the geometric mean standard. Scenario 2 was simulated with

an allocated outflow from Straight Creek (previously conducted TMDL). This scenario

resulted in a considerable decrease in the percentage violation of the geometric mean

standard. Eliminating illicit residential discharges or straight pipes and sewer overflows

(Scenario 3) allows the N.F. Powell River to have a 0% violation rate of the GM

swimming use standard. An appropriate Stage I scenario would be correcting half of the

straight pipes and sewer overflows.

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Powell R


Table 5.13 Allocation scenarios for reducing current bacteria loads in N.F. Powell River (subwatershed 46, 47, 48, 49, 50, 55, 56, 58, 59, and Straight Creek).

Percent Reductions to Existing Bacteria Loads



Human Direct


VADEQ E. coli

Standard percent

violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture,

LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 75.7

2 (with

allocated Straight Creek)

0 0 0 0 0 0 0

12.22 31 0 0 0 0 100 100 0 0





concentrations, from the N.F. Powell River impairment outlet. The graph shows existing


1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)


Figure 5.4 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 56, N.F. Powell River impairment outlet.

Table 5.14 contains estimates of existing and allocated in-stream E. coli loads at the N.F.






Tables A.10, A.11, and A.12 in Appendix A include the monthly land-based fecal

coliform load distribution, the monthly direct nonpoint source fecal coliform load by





evaluation.

Table 5.14 Estimated existing and allocated E. coli in-stream loads in the N.F. Powell River impairment.


Existing Run1


Allocation Run1

Percent Reduction




Total Loads 5.31E+14 1.12E+14 73.4%










Table 5.15 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the N.F. Powell River impairment.


N.F. Powell River

2.17E+12 1.10E+14 1.12E+14

VA0029599 1.05E+12 VAG400117 1.74E+09 Future Load 1.12E+12

Implicit





bacterial TMDLs. The daily average in-stream loads for N.F. Powell River are shown in




conditions.

Table 5.16 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in N.F. Powell River impairment.


N.F. Powell River

5.93E+09 1.04E+13 1.04E+13

VA0029599 2.86E+09 VAG400117 4.77E+06 Future Load 3.06E+09

Implicit




5.4.5 Wallen Creek (VAS-P22_WAL01A00)

Wallen Creek impairment is one of the headwaters impairments in this report and does

not receive inflow from other impairments. Unlike the impairments discussed so far in

this chapter, Wallen Creek flows into the Powell River below the downstream end of the

most downstream Powell River bacteria impairment. Therefore, allocations in Wallen

Creek are not expected to impact any of the current bacteria impaired segments on the

Powell River. Table 5.17 shows allocation scenarios used to determine the final TMDL

for Wallen Creek. The existing condition, Scenario 1, shows 15.4% violations of the

geometric mean standard. Scenario 2 explores the impact of eliminating straight pipes

and sewer overflows. This scenario shows a considerable improvement but is not enough

to meet the standard. In Scenario 3, half the cattle direct deposition is assumed to be

eliminated. While this scenario showed an improvement, it was nonetheless not enough.

The final allocation scenario (Scenario 4) allows Wallen Creek to have a 0% violation

rate of the GM swimming use standard by completely fencing out cattle from the stream.

An appropriate Stage I scenario would be correcting all of the straight pipes and sewer

overflows.

ALLO

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TION

5-25

TMD

L Developm

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Powell R


Table 5.17 Allocation scenarios for reducing current bacteria loads in Wallen Creek (subwatershed 18,19,21,23,24,25). Percent Reductions to Existing Bacteria Loads



Human Direct


VADEQ E. coli

Standard percent

violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture,

LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 15.4

2 0 0 0 0 100 100 0 2.4 3 0 0 50 0 100 100 0 1.8 41 0 0 100 0 100 100 0 0





concentrations, from the Wallen Creek impairment outlet. The graph shows existing


1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)


Figure 5.5 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 24, Wallen Creek impairment outlet.

Table 5.18 contains estimates of existing and allocated in-stream E. coli loads at the

Wallen Creek impairment outlet reported as average annual cfu per year. The estimates

in Table 5.18 are generated from available data, and these values are specific to the










evaluation.

Table 5.18 Estimated existing and allocated E. coli in-stream loads in Wallen Creek impairment.


Existing Run1


Allocation Run1

Percent Reduction




Total Loads 1.89E+14 1.16E+14 54.2%










Table 5.19 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in Wallen Creek impairment.


Wallen Creek 1.16E+12 1.15E+14 1.16E+14 Future Load 1.16E+12

Implicit





bacterial TMDLs. The daily average in-stream loads for Wallen Creek are shown in




conditions.

Table 5.20 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Wallen Creek impairment.


Wallen Creek 3.18E+09 7.58E+12 7.58E+12 Future Load 3.18E+09 Implicit


5.4.6 Middle Powell River (VAS-P19R_POW03A00)

The Middle Powell River impairment receives outflow from the Upper Powell River

Impairment, the S.F. Powell impairment, and Butcher Fork impairment. Table 5.21

shows allocation scenarios used to determine the final TMDL for the Middle Powell

River. The existing condition, Scenario 1, shows 35.2% violations of the geometric mean

standard. Scenario 2 was simulated with an allocated outflow from Callahan Creek



(previously conducted TMDL). This scenario resulted in an improvement that was not

sufficient enough. Scenario 3 explores the impact of using an allocated outflow from all

the upstream impairments including the Upper Powell River impairment, the S.F. Powell

River impairment, and Butcher Fork impairment. This scenario shows an additional

improvement. However, additional reductions were needed in upstream subwatersheds

that were not part of the contributing area to any of the upstream impairments

(subwatersheds 6,7,8,9,10,30,31,32,69). Eliminating illicit residential discharges or

straight pipes and sewer overflows (Scenario 4) allows the Middle Powell River to have a

0% violation rate of the GM swimming use standard. An appropriate Stage I scenario

would be correcting half of the straight pipes and sewer overflows.

BA

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Table 5.21 Allocation scenarios for reducing current bacteria loads in Middle Powell River (subwatershed 6,7,8,9,10,30,31,32,69,Upper Powell River, S.F. Powell River, and Butcher Fork impairments).




Human Direct

Human and Pet Land

Based

VADEQ E. coli Standard

percent violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture, LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 35.2

2 (with allocated

Callahan Creek)

0 0 0 0 0 0 0

34.8 3

(with allocated Upper Powell

River, S.F. Powell River, and Butcher

Fork)

0 0 0 0 0 0 0

26.3 41 0 0 0 0 100 100 0 0





concentrations, from the Middle Powell River impairment outlet. The graph shows

existing conditions in blue, with allocated conditions overlaid in black.

1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)


Figure 5.6 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 10, Middle Powell River impairment outlet.


Middle Powell River impairment outlet reported as average annual cfu per year. The

estimates in Table 5.22 are generated from available data, and these values are specific to

the impairment outlet for the allocation rainfall for the current land use distribution in the









evaluation.

Table 5.22 Estimated existing and allocated E. coli in-stream loads in the Middle Powell River impairment.


Existing Run1


Allocation Run1

Percent Reduction




Total Loads 1.10E+15 2.58E+14 80.0%







set aside for future growth in the WLA portion. The future load in the Middle Powell

River impairment was further increased to account for the proposed wastewater treatment

plant near Norton, Virginia with a design flow of 2 MGD.



Table 5.23 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Middle Powell River impairment.

Impairment WLA1 LA MOS TMDL Middle Powell River 9.65E+12 2.48E+14 2.58E+14

VA0060798 2.09E+10 VA0075515 2.26E+10 VA0020940 3.48E+12 VAG400227 1.74E+09 VAG400016 1.74E+09 VAG400383 1.74E+09 VAG400392 1.74E+09 VAG400395 1.74E+09 VAG400505 1.74E+09 VAG400089 1.74E+09 VAG400253 1.74E+09 VAG400049 1.74E+09 VAG400347 1.74E+09 VAG400517 1.74E+09 VAG400373 1.74E+09 VAG400135 1.74E+09 VAG400151 1.74E+09 VAG400166 1.74E+09 VAG400275 1.74E+09 VAG400281 1.74E+09 VAG400228 1.74E+09 VAG400099 1.74E+09 VAG400128 1.74E+09 VAG400462 1.74E+09 VAG400470 1.74E+09 VAG400169 1.74E+09 VAG400748 1.74E+09 VAG400640 1.74E+09 VAG400389 1.74E+09 VAG400601 1.74E+09 VAG400670 1.74E+09 VAG400642 1.74E+09 VAG400711 1.74E+09 VAG400355 1.74E+09 VAG400685 1.74E+09 VAG400429 1.74E+09 VAG400432 1.74E+09 VAG400715 1.74E+09 Future Load 6.06E+12

Implicit







bacterial TMDLs. The daily average in-stream loads for Middle Powell River are shown

in Table 5.24. The daily TMDL was calculated using the 99th percentile daily flow



conditions.



Table 5.24 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Middle Powell River impairment.

Impairment WLA1 LA MOS TMDL2 Middle Powell River 2.64E+10 2.37E+13 2.38E+13

VA0060798 5.73E+07 VA0075515 6.20E+07 VA0020940 9.55E+09 VAG400227 4.77E+06 VAG400016 4.77E+06 VAG400383 4.77E+06 VAG400392 4.77E+06 VAG400395 4.77E+06 VAG400505 4.77E+06 VAG400089 4.77E+06 VAG400253 4.77E+06 VAG400049 4.77E+06 VAG400347 4.77E+06 VAG400517 4.77E+06 VAG400373 4.77E+06 VAG400135 4.77E+06 VAG400151 4.77E+06 VAG400166 4.77E+06 VAG400275 4.77E+06 VAG400281 4.77E+06 VAG400228 4.77E+06 VAG400099 4.77E+06 VAG400128 4.77E+06 VAG400462 4.77E+06 VAG400470 4.77E+06 VAG400169 4.77E+06 VAG400748 4.77E+06 VAG400640 4.77E+06 VAG400389 4.77E+06 VAG400601 4.77E+06 VAG400670 4.77E+06 VAG400642 4.77E+06 VAG400711 4.77E+06 VAG400355 4.77E+06 VAG400685 4.77E+06 VAG400429 4.77E+06 VAG400432 4.77E+06 VAG400715 4.77E+06 Future Load 1.66E+10

Implicit




5.4.7 Lower Powell River (VAS-P21R_POW02A02)

The Lower Powell River impairment receives outflow from the Middle Powell River

impairment (and therefore from N.F. Powell River and Butcher Fork impairments) and

the N.F. Powell River impairment. Table 5.25 shows allocation scenarios used to

determine the final TMDL for the Upper Powell River. The existing condition, Scenario

1, shows 25.4% violations of the geometric mean standard. Scenario 2 was simulated

with an allocated outflow from the Middle Powell River impairment. This scenario

resulted in a considerable improvement that was not sufficient enough. Eliminating

illicit residential discharges or straight pipes and sewer overflows (Scenario 4) from

swbwatersheds 11, 12, 13, 14, and 26 allows the Lower Powell River to have a 0%

violation rate of the GM swimming use standard. An appropriate Stage I scenario would

be correcting half of the straight pipes and sewer overflows.

BA

CTER

IAL A

LLOC

ATIO

N

5-37

TMD

L Developm

ent Pow


A

Table 5.25 Allocation scenarios for reducing current bacteria loads in Lower Powell River (subwatershed 11,12,13,14,26 and the Middle Powell River impairment).




Human Direct

Human and Pet Land

Based

VADEQ E. coli Standard

percent violations


Barren, Commercial,

Forest, Active, AML

Livestock Direct

Cropland, Pasture, LAX

Straight Pipes


1 (existing) 0 0 0 0 0 0 0 25.4

2 (with allocated Middle Powell

River impairment)

0 0 0 0 0 0 0

2.1 31 0 0 0 0 100 100 0 0


TMDL Development Powell River and Tributaries , VA

5-38 BACTERIAL ALLOCATION


concentrations, from the Lower Powell River impairment outlet. The graph shows

existing conditions in blue, with allocated conditions overlaid in black.

1

10

100

1,000

10/1/1992 4/19/1993 11/5/1993 5/24/1994 12/10/1994 6/28/1995 1/14/1996 8/1/1996

Date

E.c

oli

Con

cent

ratio

n (c

fu/1

00m

l)


Figure 5.7 Existing and allocated monthly geometric mean in-stream E. coli concentrations in subwatershed 14, Lower Powell River impairment outlet.


Lower Powell River impairment outlet reported as average annual cfu per year. The

estimates in Table 5.26 are generated from available data, and these values are specific to

the impairment outlet for the allocation rainfall for the current land use distribution in the









evaluation.

Table 5.26 Estimated existing and allocated E. coli in-stream loads in the Lower Powell River impairment.


Existing Run1


Allocation Run1

Percent Reduction




Total Loads 1.77E+15 5.58E+14 77.1%







set aside for future growth in the WLA portion. The future load in the Lower Powell

River impairment was further increased to account for the proposed wastewater treatment

plant near Norton, Virginia with a design flow of 2 MGD.



Table 5.27 Final average annual in-stream E. coli bacterial loads (cfu/year) modeled after TMDL allocation in the Lower Powell River impairment.


Lower Powell River 1.51E+13 5.43E+14 5.58E+14

VA0029599 1.05E+12 VA0060798 2.09E+10 VA0063941 8.54E+09 VA0089397 1.39E+12 VA0020940 3.48E+12 VA0075515 5.23E+09 VAG400227 1.74E+09 VAG400016 1.74E+09 VAG400383 1.74E+09 VAG400392 1.74E+09 VAG400395 1.74E+09 VAG400505 1.74E+09 VAG400089 1.74E+09 VAG400253 1.74E+09 VAG400049 1.74E+09 VAG400347 1.74E+09 VAG400517 1.74E+09 VAG400373 1.74E+09 VAG400135 1.74E+09 VAG400151 1.74E+09 VAG400166 1.74E+09 VAG400275 1.74E+09 VAG400281 1.74E+09 VAG400228 1.74E+09 VAG400099 1.74E+09 VAG400117 1.74E+09 VAG400128 1.74E+09 VAG400462 1.74E+09 VAG400470 1.74E+09 VAG400169 1.74E+09 VAG400748 1.74E+09 VAG400640 1.74E+09 VAG400389 1.74E+09 VAG400601 1.74E+09 VAG400670 1.74E+09 VAG400642 1.74E+09 VAG400711 1.74E+09 VAG400355 1.74E+09 VAG400685 1.74E+09 VAG400429 1.74E+09 VAG400432 1.74E+09 VAG400715 1.74E+09

Implicit

Future Load 9.06E+12







bacterial TMDLs. The daily average in-stream loads for Lower Powell River are shown

in Table 5.28. The daily TMDL was calculated using the 99th percentile daily flow



conditions.



Table 5.28 Final average daily in-stream E. coli bacterial loads (cfu/day) modeled after TMDL allocation in Lower Powell River impairment.

Impairment WLA1 LA MOS TMDL Implicit

Lower Powell River

4.13E+10 3.70E+13 3.71E+13

VA0029599 2.86E+09 VA0060798 5.73E+07 VA0063941 2.34E+07 VA0089397 3.82E+09 VA0020940 9.55E+09 VA0075515 1.43E+07 VAG400227 4.77E+06 VAG400016 4.77E+06 VAG400383 4.77E+06 VAG400392 4.77E+06 VAG400395 4.77E+06 VAG400505 4.77E+06 VAG400089 4.77E+06 VAG400253 4.77E+06 VAG400049 4.77E+06 VAG400347 4.77E+06 VAG400517 4.77E+06 VAG400373 4.77E+06 VAG400135 4.77E+06 VAG400151 4.77E+06 VAG400166 4.77E+06 VAG400275 4.77E+06 VAG400281 4.77E+06 VAG400228 4.77E+06 VAG400099 4.77E+06 VAG400117 4.77E+06 VAG400128 4.77E+06 VAG400462 4.77E+06 VAG400470 4.77E+06 VAG400169 4.77E+06 VAG400748 4.77E+06 VAG400640 4.77E+06 VAG400389 4.77E+06 VAG400601 4.77E+06 VAG400670 4.77E+06 VAG400642 4.77E+06 VAG400711 4.77E+06 VAG400355 4.77E+06



Impairment WLA1 LA MOS TMDL Implicit

Lower Powell River

4.13E+10 3.70E+13 3.71E+13

VAG400685 4.77E+06 VAG400429 4.77E+06 VAG400432 4.77E+06 VAG400715 4.77E+06 Future Load 2.48E+10



WATER QUALITY ASSESSMENT 6-1

6. WATER QUALITY ASSESSMENT

6.1 Applicable Criterion for Benthic Impairment

The General Standard, as defined in Virginia state law 9 VAC 25-260-20, states:

A. All state waters, including wetlands, shall be free from substances attributable to sewage, industrial waste, or other waste in concentrations, amounts, or combinations which contravene established standards or interfere directly or indirectly with designated uses of such water or which are inimical or harmful to human, animal, plant, or aquatic life.

The General Standard use was implemented by VADEQ through application of the

modified Rapid Bioassessment Protocol II (RBP II) (Barbour et al, 1999). However, in

January 2008 VADEQ moved to a multimetric index approach called the Virginia Stream

Condition Index (VASCI) (Burton, 2003). The health of the benthic macroinvertebrate

community is assessed through measurement of eight biometrics statistically derived

from numerous reference sites in the non-coastal regions of Virginia (Table 6.1).

Surveys of the benthic macroinvertebrate community performed by VADEQ are assessed

at the family taxonomic level. VADEQ’s not impaired benchmark with VASCI is a total

score of 60 (10th percentile of the reference sites).

Table 6.1 Components of the VASCI. Biometric Benthic Health 1

Total Taxa Score ↑ % Plecoptera plus Trichoptera less Hydopschyidae Score ↑

% Ephemeroptera Score ↑ %Scraper Score ↑ EPT Taxa Score ↑ % Two Dominant Families Score ↓ % Chironomidae Score ↓ Modified Family Biotic Index (MFBI) Score ↓ 1 An upward arrow indicates a positive response in benthic health when the associated biometric increases.

6.2 Benthic Assessment – Powell River

The Powell River was initially listed on the 1996 303(d) TMDL Priority List as not

supporting aquatic life and additional impaired segments have been added on subsequent

lists. The VADEQ 2006 integrated 305(b)/303(d) list reported that there were three


6-2 WATER QUALITY ASSESSMENT

impaired benthic monitoring stations on the Powell River; 6BPOW120.12,

6BPOW166.97 and 6BPOW180.72. In January 2008 VADEQ began using the VASCI,

and this new index will result in additional benthic monitoring stations being reprted as

impaired on the Powell River. All VADEQ biological, special study and ambient water

quality monitoring stations on the Powell River are shown in Table 6.2 and Figure 6.1.

Table 6.2 VADEQ monitoring stations on the Powell River. Station Station Type River Mile

6BPOW120.12 Benthic 120.12 6BPOW121.76 Special Study – Fish Tissue & Sediment 121.76 6BPOW123.64 Special Study – Metals & Toxics 123.64 6BPOW128.37 Special Study – Fish Tissue & Sediment 128.37 6BPOW133.00 Special Study – Metals & Toxics 133.00 6BPOW138.91 Ambient 138.91 6BPOW141.45 Special Study – Metals & Toxics 141.45 6BPOW143.53 Special Study – Metals & Toxics 143.53 6BPOW143.81 Special Study – Fish Tissue & Sediment 143.81 6BPOW156.57 Benthic 156.57 6BPOW158.45 Benthic 158.45 6BPOW162.89 Benthic 162.89 6BPOW165.78 Ambient 165.78 6BPOW166.97 Benthic 166.92 6BPOW166.97 Benthic 166.97 6BPOW170.76 Special Study – Metals & Toxics 170.76 6BPOW178.33 Special Study – Fish Tissue & Sediment 178.33 6BPOW179.20 Ambient/Benthic 179.20 6BPOW180.72 Benthic 180.72 6BPOW184.19 Benthic 184.19



Figure 6.1 Biological, special study and ambient water quality monitoring stations on the Powell River.

Nine benthic surveys were performed by the VADEQ from November 1996 through

October 2008 at benthic monitoring station 6BPOW120.12. The VASCI scores are

presented in Table 6.3 and Figure 6.2. The December 1997, June 1999, May 2007, and

May 2008 surveys found impaired benthic conditions. The remaining surveys indicated

non impaired conditions.



Table 6.3 VASCI biological monitoring data for station 6BPOW120.12 on the Powell River.

Metric 11/7/96 12/17/97 10/21/98 6/21/99 6/15/00 5/23/07 9/19/07 Richness Score 68 55 50 55 68 50 50 EPT Score 73 55 64 55 73 55 64 %Ephem Score 53 59 64 22 44 31 27 %PT-H Score 34 9 37 8 13 3 22 %Scraper Score 56 26 41 100 100 97 100 %Chironomidae Score 95 85 93 96 95 89 95

%2Dom Score 84 60 71 37 62 71 61 %MFBI Score 93 84 91 88 90 80 86 VASCI 70 54 64 58 68 59 63

Assessment Not Impaired Impaired Not

Impaired Impaired Not Impaired Impaired Not

Impaired*%PT – Hydropsychidae Table 6.3 VASCI biological monitoring data for station 6BPOW120.12 on the

Powell River (cont.). Metric 5/22/2008 10/29/2008

Richness Score 55 68 EPT Score 55 64 %Ephem Score 8 30 %PT-H Score 14 71 %Scraper Score 61 96 %Chironomidae Score 77 99

%2Dom Score 82 83 %MFBI Score 69 93 VASCI 53 75 Assessment Impaired Not Impaired*%PT – Hydropsychidae



0

20

40

60

80

100

11/96 12/97 10/98 6/99 6/00 5/07 9/07 5/08 10/08

VASC

I Sco

re

Impaired

Not ImpairedVASCI Impairmentthreshold = 60

Figure 6.2 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPOW120.12 on the Powell River.

Two benthic surveys were performed by the VADEQ in May and October of 2001 at

benthic monitoring station 6BPOW156.57. The VASCI scores are presented in Table 6.4

and Figure 6.3. The results indicate impaired conditions were found in the spring and fall

2001 surveys.


Metric 5/15/01 10/27/01 Richness Score 55 41 EPT Score 45 36 %Ephem Score 17 13 %PT-H* Score 3 0 %Scraper Score 100 92 %Chironomidae Score 79 98

%2Dom Score 81 44 %MFBI Score 80 74 VASCI Score 57 50 Assessment Impaired Impaired

*%PT – Hydropsychidae



0

20

40

60

80

100

5/01 10/01

VASC

I Sco

re

Impaired

Not Impaired

VASCI Impairment threshold = 60


One benthic survey was performed by the VADEQ in November of 1996 at benthic

monitoring station 6BPOW158.45. The VASCI score is presented in Table 6.5 and

Figure 6.4. The result indicates that the survey found a not impaired condition.




Metric 11/7/96 Richness Score 64 EPT Score 64 %Ephem Score 71 %PT-H* Score 71 %Scraper Score 40 %Chironomidae Score 95 %2Dom Score 68 %MFBI Score 99 VASCI Score 71 Assessment Not Impaired


0

20

40

60

80

100

11/96

VASC

I Sco

re

VASCI Impairment threshold = 60 Not Impaired

Impaired




One benthic survey was performed by the VADEQ in April of 2007 at benthic

monitoring station 6BPOW162.89. The VASCI score is presented in Table 6.6 and

Figure 6.5. The result indicates that the survey found an impaired condition.


Metric 4/30/07 Richness Score 64 EPT Score 55 %Ephem Score 61 %PT-H* Score 3 %Scraper Score 37 %Chironomidae Score 73 %2Dom Score 64 %MFBI Score 74 VASCI Score 54 Assessment Impaired


0

20

40

60

80

100

4/07

VASC

I Sco

re

Impaired

Not ImpairedVASCI Impairment threshold = 60




Five benthic surveys were performed by the VADEQ in November, 1998, May 2006,

November 2006, May 2008 and October 2008 at benthic monitoring station

6BPOW166.97. The VASCI scores are presented in Table 6.7 and Figure 6.6. The

results indicate that the surveys found a not impaired conditions in the fall of 1998,

impaired condition in the spring of 2006 and a non-impaired condition in the fall of 2006.


Metric 11/24/98 5/11/06 11/01/06 5/19/2008 10/29/2008 Richness Score 45 55 77 59 91 EPT Score 27 55 73 55 100 %Ephem Score 82 25 56 16 33 %PT-H* Score 0 11 26 20 32 %Scraper Score 81 52 100 50 84 %Chironomidae Score 87 54 97 74 96 %2Dom Score 71 52 73 70 70 %MFBI Score 86 74 90 72 81 VASCI Score 60 47 74 52 73

Assessment Not Impaired Impaired Not

Impaired Impaired Not Impaired


0

20

40

60

80

100

11/98 5/06 11/06 5/08 10/08

VASC

I Sco

re

Impaired





Two benthic surveys were performed by the VADEQ in April and October of 2006 and

one survey in September of 2008 at benthic monitoring station 6BPOW179.20. The

VASCI scores are presented in Table 6.8 and Figure 6.7. The results indicate that the

surveys found an impaired condition in all three surveys.


Metric 4/20/06 10/16/06 9/25/2008 Richness Score 50 50 68 EPT Score 36 36 36 %Ephem Score 18 24 44 %PT-H* Score 0 0 0 %Scraper Score 13 83 80 %Chironomidae Score 49 86 86 %2Dom Score 54 52 80 %MFBI Score 62 79 79 VASCI Score 35 51 59 Assessment Impaired Impaired Impaired


0

20

40

60

80

100

4/06 10/06 9/08

VASC

I Sco

re

Impaired

Not Impaired





Four benthic surveys were performed by the VADEQ in November 1997, November

1998, June 1999 and December 2003 at benthic monitoring station 6BPOW180.72. The

VASCI scores are presented in Table 6.9 and Figure 6.8. The results indicate that the

surveys found an impaired conditions in 1997, 1998 and 1999. A non-impaired condition

was found in the fall of 2003.


Metric 11/20/97 11/24/98 6/14/99 12/16/03 Richness Score 23 55 50 45 EPT Score 9 36 27 45 %Ephem Score 0 44 77 58 %PT-H* Score 0 23 0 62 %Scraper Score 43 22 24 22 %Chironomidae Score 54 89 88 86

%2Dom Score 41 75 76 80 %MFBI Score 59 88 86 88 VASCI Score 29 54 54 61 Assessment Impaired Impaired Impaired Not Impaired


0

20

40

60

80

100

11/97 6/98 11/98 12/03

VASC

I Sco

re

Impaired





Two benthic surveys were performed by the VADEQ in April and October 2007 at

benthic monitoring station 6BPOW184.19. The VASCI scores are presented in Table

6.10 and Figure 6.9. The results indicate that the surveys found impaired conditions in

both surveys.


Metric 4/10/07 10/29/07 Richness Score 50 59 EPT Score 36 55 %Ephem Score 54 33 %PT-H* Score 0 14 %Scraper Score 8 6 %Chironomidae Score 82 98 %2Dom Score 83 32 %MFBI Score 65 77 VASCI Score 47 47 Assessment Impaired Impaired


0

20

40

60

80

100

4/07 10/07

VASC

I Sco

re

Impaired





6.2.1 Coal Slurry Spill in the Powell River Basin October 24, 1996

Subsidence in a Lone Mountain Processing, Inc. LMPI impoundment caused coal slurry

to reach a network of underground mines. Coal slurry consists of coal fines, water, and a

variety of chemicals used to wash coal. The majority of the contaminants are considered

PAHs (Polycyclic aromatic hydrocarbons). The slurry entered state surface waters at Gin

Creek and killed 11,240 fish in 8.5 miles involving Straight Creek and the North Fork

Powell River (VADEQ, 1996). A benthic monitoring survey was performed on the

Powell River following the spill to assess the impact if any on benthic community in the

river. Two stations were monitored, one approximately one mile upstream of the North

Fork Powell River confluence and one downstream near the Tennessee/Virginia State

line. Table 6.11 shows the results of these benthic surveys. The results at both

monitoring stations were not impaired.

Table 6.11 VASCI biological monitoring data for two VADEQ benthic monitoring stations on the Powell River, November 7, 1996.

Metric 6BPOW158.45 6BPOW120.12 Richness Score 68 64 EPT Score 73 64 %Ephem Score 53 71 %PT-H* Score 34 71 %Scraper Score 56 40 %Chironomidae Score 95 95 %2Dom Score 84 68 %MFBI Score 93 99 VASCI Score 70 71 Assessment Not Impaired Not Impaired

6.3 Benthic Assessment – North Fork Powell River

The North Fork Powell River was initially listed on the 1996 303(d) TMDL Priority List

as not supporting aquatic life. All biological and ambient water quality monitoring

stations on the North Fork Powell River are shown in Table 6.12 and Figure 6.10.



Table 6.12 Benthic, ambient and special study monitoring stations on the North Fork Powell River.

Station Station Type River Mile 6BPWL000.06 Biological 0.06 6BPWL001.49 Special Study – Sediment metals/organics 1.49 6BPWL001.62 Special Study – Fish Tissue & Sediment 1.62 6BPWL001.93 Biological 1.93 6BPWL002.48 Special Study – Fish Tissue & Sediment 2.48 6BPWL004.10 Ambient/ Special Study – Sediment metals/organics 4.1 6BPWL004.40 Biological 4.4 6BPWL006.16 Biological 6.16 6BPWL006.59 Ambient 6.59

Figure 6.10 Biological, special study and ambient water quality monitoring stations on the North Fork Powell River.

VADEQ performed a benthic monitoring at VADEQ benthic monitoring station

6BPWL000.06 in May of 2002 and October of 2002. The VASCI scores are presented in



Table 6.13 and Figure 6.11. The results indicate impaired benthic conditions during both

surveys.

Table 6.13 VASCI biological monitoring data for station 6BPWL000.06 on the North Fork Powell River.

Metric 5/16/02 10/08/02 Richness Score 59 41 EPT Score 45 27 %Ephem Score 63 16 %PT-H* Score 9 0 %Scraper Score 36 100 %Chironomidae Score 67 97 %2Dom Score 46 16 %MFBI Score 79 88 VASCI Score 51 48 Assessment Impaired Impaired

0

20

40

60

80

100

5/02 10/02

VASC

I Sco

re

Impaired


Figure 6.11 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPWL000.06 on the North Fork Powell River.

Two benthic surveys were performed by the VADEQ in May and November of 2006 at

benthic monitoring station 6BPWL001.93. The VASCI scores are presented in Table



6.14 and Figure 6.12. The results indicate that the spring survey found an impaired

benthic condition while the fall survey found a non-impaired benthic condition.

Table 6.14 VASCI biological monitoring data for station 6BPWL001.93 on the North Fork Powell River.

Metric 5/11/06 11/01/06 Richness Score 50 86 EPT Score 45 82 %Ephem Score 39 16 %PT-H* Score 5 23 %Scraper Score 35 100 %Chironomidae Score 62 98 %2Dom Score 56 66 %MFBI Score 73 88 VASCI Score 46 70 Assessment Impaired Not Impaired


0

20

40

60

80

100

5/06 11/06

VASC

I Sco

re

Impaired


Figure 6.12 VASCI biological monitoring scores for VADEQ benthic monitoring station 6PWL001.93 on the North Fork Powell River.

Seven benthic surveys were performed by the VADEQ in November 1996, November

1998, September 1999, December 2003, June 2004, May 2008 and October 2008 at

benthic monitoring station 6BPWL004.40. The VASCI scores are presented in Table



6.15 and Figure 6.13. The results indicate that the surveys found impaired conditions in

1996, 1998, 1999, 2003 and a not impaired condition was found in 2004.

Table 6.15 VASCI data for VADEQ station 6BPWL004.40 on the North Fork Powell River.

Metric 11/7/96 11/24/98 9/10/99 12/16/03 6/7/04 5/19/08 10/29/08 Richness Score 64 50 64 41 68 41 59 EPT Score 55 45 36 36 64 27 36 %Ephem Score 59 54 87 18 79 23 32 %PT-H* Score 43 5 3 52 15 3 42 %Scraper Score 13 11 12 21 34 12 88 %Chironomidae Score 86 89 96 64 87 71 93

%2Dom Score 66 34 57 65 92 45 57 %MFBI Score 90 82 92 78 87 65 94 VASCI Score 59 46 56 47 66 36 63

Assessment Impai-red

Impai-red

Impai-red

Impai-red

Not Impaired

Impai-red

Not Impaired


0

20

40

60

80

100

11/96 11/98 9/99 12/03 6/04 5/08 10/08

VASC

I Sco

re

Impaired



Two benthic surveys were performed by the VADEQ in December 2003 and June of

2004 at benthic monitoring station 6BPWL006.16. The VASCI scores are presented in



Table 6.16 and Figure 6.14. The results indicate that the surveys found non-impaired

conditions in the fall of 2003 and spring of 2004.

Table 6.16 VASCI data for VADEQ station 6BPWL006.16 on the North Fork Powell River.

Metric 12/09/03 6/07/04 Richness Score 45 68 EPT Score 64 64 %Ephem Score 45 63 %PT-H* Score 100 18 %Scraper Score 45 57 %Chironomidae Score 91 89 %2Dom Score 71 72 %MFBI Score 100 91 VASCI Score 70 65 Assessment Not Impaired Not Impaired


0

20

40

60

80

100

12/03 6/04

VASC

I Sco

re

Impaired

Not Impaired



Section 6.2.1 describes a coal slurry spill that occurred in the North Fork Powell

watershed (Gin Creek a tributary to Straight Creek) on October 24, 1996. In addition to



benthic monitoring on the Powell River, VADEQ also monitored two stations on the

North Fork Powell on November 7, 1996, the results are shown in Tables 6.14 and 6.15.

Monitoring station 6BPWL004.40 was impaired.

6.4 Benthic Assessment – South Fork Powell River

The South Fork Powell River was initially listed on the 1996 303(d) TMDL Priority List

as not supporting aquatic life. All biological and ambient water quality monitoring

stations on the South Fork Powell River are shown in Table 6.17 and Figure 6.15.

Table 6.17 Benthic and ambient monitoring stations on the South Fork Powell River.

Station Station Type River Mile 6BPLL000.17 Benthic 0.17 6BPLL000.27 Ambient 0.27 6BPLL001.61 Benthic 1.61 6BPLL002.55 Ambient/Benthic 2.55 6BPLL004.24 Ambient 4.24 6BPLL004.49 Benthic 4.49 6BPLL006.38 Benthic/Special Study – Sediment metals 6.38



Figure 6.15 Biological and ambient water quality monitoring stations on the South Fork Powell River.

One benthic survey was performed by the VADEQ in June 2001 at benthic monitoring

station 6BPLL000.17. The VASCI score is presented in Table 6.18 and Figure 6.16. The

results indicate that non-impaired conditions were found.



Table 6.18 VASCI data for VADEQ station 6BPLL000.17 on the South Fork Powell River.

Metric 06/25/2001 Richness Score 50 EPT Score 45 %Ephem Score 40 %PT-H* Score 97 %Scraper Score 35 %Chironomidae Score 94 %2Dom Score 75 %MFBI Score 93 VASCI Score 66 Assessment Not Impaired


0

20

40

60

80

100

6/01

VASC

I Sco

re


Impaired

Figure 6.16 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL000.17 on the South Fork Powell River.

Two benthic surveys were performed by the VADEQ in March 2008 and October 2008 at

benthic monitoring station 6BPLL001.61. The VASCI scores are presented in Table 6.19



and Figure 6.17. The results indicate that impaired conditions were found in the spring

and non-impaired conditions were found in the fall.


Metric 03/25/2001 10/15/2008 Richness Score 59 68 EPT Score 45 55 %Ephem Score 17 55 %PT-H* Score 0 54 %Scraper Score 100 82 %Chironomidae Score 70 94 %2Dom Score 47 79 %MFBI Score 75 90 VASCI Score 52 72 Assessment Impaired Not Impaired


0

20

40

60

80

100

3/08 10/08

VASC

I Sco

re


Impaired

Figure 6.17 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL001.61 on the South Fork Powell River.



Seven benthic surveys were performed by the VADEQ in November 1997, April 1998,

August 1998, May 2007, September 2007, May 2008 and October 2008 at benthic

monitoring station 6BPLL002.55. The VASCI scores are presented in Table 6.20 and

Figure 6.18. The results indicate that non-impaired conditions were found in the fall of

1998, 2007 and 2008, but the remaining surveys found impaired conditions.


Metric 4/18/96 11/20/97 8/31/98 5/22/07 9/18/07 5/19/08 10/29/08 Richness Score 36 64 64 59 59 45 73

EPT Score 18 45 55 55 64 27 73 %Ephem Score 16 43 41 82 65 34 23

%PT-H* Score 0 2 4 0 10 0 17

%Scraper Score 52 72 91 29 49 55 100

%Chironomidae Score

39 89 96 91 82 68 87

%2Dom Score 28 69 75 71 95 68 69

%MFBI Score 70 85 85 73 80 70 78

VASCI Score 32 59 64 57 63 46 65

Assessment Impaired Impaired Not Impaired Impaired Not

Impaired Impaired Not Impaired




0

20

40

60

80

100

4/96 11/97 8/98 5/07 9/07 5/08 10/08

VASC

I Sco

re

Impaired


Figure 6.18 VASCI biological monitoring scores for VADEQ benthic monitoring station 6BPLL002.55 on South Fork Powell River.

One benthic survey was performed by the VADEQ August 31, 1998 at benthic

monitoring station 6BPLL004.49 and the result was not impaired, Table 6.21 and Figure

6.19.


Metric 8/31/98 Richness Score 64 EPT Score 55 %Ephem Score 41 %PT-H* Score 4 %Scraper Score 91 %Chironomidae Score

96

%2Dom Score 75 %MFBI Score 85 VASCI Score 64 Assessment Not Impaired



0

20

40

60

80

100

8/98

VASC

I Sco

re

Impaired



One benthic survey was performed by the VADEQ in August 1998 at benthic monitoring

station 6BPLL006.38. The VASCI scores are presented in Table 6.22 and Figure 6.20.

The result of the survey found a non-impaired benthic condition.


Metric 8/31/98 Richness Score 77 EPT Score 64 %Ephem Score 47 %PT-H* Score 38 %Scraper Score 64 %Chironomidae Score

87

%2Dom Score 100 %MFBI Score 87 VASCI Score 70 Assessment Not Impaired




0

20

40

60

80

100

8/98

VASC

I Sco

re


Not Impaired

Impaired


6.5 Habitat Assessments

Benthic impairments have two general causes: input of pollutants to streams and

alteration of habitat in either the stream or the watershed. Habitat can be altered directly

(e.g., by channel modification), indirectly (because of changes in the riparian corridor

leading to conditions such as streambank destabilization), or even more indirectly (e.g.,

due to land use changes in the watershed, such as clearing large areas).

Habitat assessments are normally carried out as part of the benthic sampling. The overall

habitat score is the sum of ten individual metrics, each metric ranging from 0 to 20. The

classification schemes for both the individual habitat metrics and the overall habitat score

for a sampling site are shown in Table 6.23.



Table 6.23 Classification of habitat metrics based on score. Habitat Metric Optimal Sub-optimal Marginal Poor

Embeddedness 16 - 20 11 – 15 6 - 10 0 - 5 Epifaunal Substrate 16 - 20 11 – 15 6 - 10 0 - 5 Pool Sediment 16 - 20 11 – 15 6 - 10 0 - 5 Flow 16 - 20 11 – 15 6 - 10 0 - 5 Channel Alteration 16 - 20 11 – 15 6 - 10 0 - 5 Riffles 16 - 20 11 – 15 6 - 10 0 - 5 Velocity 16 - 20 11 – 15 6 - 10 0 - 5 Bank Stability 18 - 20 12 – 16 6 - 10 0 - 4 Bank Vegetation 18 - 20 12 – 16 6 - 10 0 - 4 Riparian Vegetation 18 - 20 12 – 16 6 - 10 0 - 4

6.5.1 Habitat Assessment at Biological Monitoring Stations –Powell River

Habitat assessment for the Powell River includes an analysis of habitat scores recorded

by the VADEQ biologist at the seven benthic monitoring stations. The VADEQ habitat

assessments for 6BPOW120.12 are displayed in Table 6.24. Embeddedness is a measure

of the silt, sand or mud that surrounds the rocks on the stream bottom. Less habitat is

available to benthic macroinvertebrates the deeper the layer of sediment becomes. The

Embeddedness score was marginal in the 1996, 1997 and 1999 surveys and much

improved during spring 2000 and both 2007 surveys but marginal again in the fall of

2008. The Pool Sediment metric assesses the amount of sediment that collects in pool

areas of the stream. The Pool Sediment score at this station was in the marginal category

during the 1997 and 1998 surveys and improved during the 2000 and 2007 surveys but

was marginal again in the fall of 2008. The average total habitat score for this benthic

monitoring station is 137, which is very good.



Table 6.24 Habitat scores for VADEQ monitoring station 6BPOW120.12 on the Powell River.

Habitat Metric 11/07/96 12/17/97 10/21/98 6/21/99 6/15/00 05/23/07 09/19/07 Channel Alteration 18 17 15 17 18 16 15

Bank Stability 11 13 8 10 13 12 11 Bank Vegetation 12 18 17 18 17 17 18 Embeddedness 8 8 12 9 17 12 13 Flow 12 18 9 10 15 14 12 Riffles 16 8 9 10 16 14 10 Riparian Vegetation 9 12 16 14 11 16 15

Pool Sediment 13 10 7 12 12 14 13 Epifaunal Substrate 12 12 17 18 16 16 18

Velocity 9 17 12 14 12 17 15 Total 120 133 122 132 147 148 140

Table 6.24 Habitat scores for VADEQ monitoring station 6BPOW120.12 on the Powell River (cont.).

Habitat Metric 05/22/08 10/29/08 Average Channel Alteration 15 15 16

Bank Stability 17 14 12 Bank Vegetation 18 17 17 Embeddedness 15 10 12 Flow 16 14 13 Riffles 8 12 11 Riparian Vegetation 18 16 14

Pool Sediment 15 10 12 Epifaunal Substrate 16 17 16

Velocity 15 15 14 Total 153 140 137

Table 6.25 shows the habitat scores for the two benthic surveys at station 6BPOW156.57

in May and October 2001. The average embeddedness score was in the marginal

category which means that a significant amount of riffle habitat is not available to the

benthic community. Pool Sediment scored in marginal category during the fall 2001

survey. The Embeddedness and Pool Sediment habitat scores indicate that excessive

sediment is a periodic problem at this monitoring station. The flow and riffles habitat



metrics also averaged in the marginal category. The total habitat score in October 2001

was below 120, which is the minimum score considered acceptable by the VADEQ.


Habitat Metric 05/15/01 10/27/01 Average Channel Alteration 19 19 19 Bank Stability 13 8 11 Bank Vegetation 18 17 18 Embeddedness 12 7 10 Flow 12 6 9 Riffles 7 8 8 Riparian Vegetation 16 13 15 Pool Sediment 13 8 11 Epifaunal Substrate 18 16 17 Velocity 18 14 16

Total 146 116 131

Table 6.26 shows the habitat scores for one benthic survey at station 66BPOW158.45 in

November 1996. The habitat scores at this station were in the marginal to poor range for

every metric except Channel Alteration. A total habitat score of 82 is very poor.


Habitat Metric 06/07/96 Channel Alteration 18 Bank Stability 8 Bank Vegetation 7 Embeddedness 6 Flow 9 Riffles 8 Riparian Vegetation 5 Pool Sediment 5 Epifaunal Substrate 9 Velocity 7

Total 82


April 2007. The riffles habitat metric scored in the marginal category at this benthic

monitoring station. The Riffles metric is a measure of the frequency that riffles occur in s



a stream. Riffles areas are some of the most important habitat areas in a high gradient

stream. The overall habitat score at this monitoring station was very good.



Total 155


November 1998. The habitat metrics pertaining to sediment, Embeddedness and

Sediment Depostion, were in the marginal category indicating that sediment was a

significant issue during this survey. The Bank Stability metric was also in the marginal

category indicating a significant amount of stream bank erosion, which contributes to the

overall sediment load in the Powell River. The overall habitat score at this monitoring

station was very poor.



Total 103



Table 6.29 shows the habitat scores for the four benthic surveys at station 6BPOW166.97

in May and November 2006. Both the Embeddedness metric and Pool Sediment metric

were in the marginal category during the spring 2006 survey indicating that excessive

sediment is a periodic problem at this monitoring station. In addition, the Riffles habitat

metric scored in the poor category during both surveys indicating that this section of the

stream is dominated by unproductive flat water. The average total habitat score of 133 is

considered good.


Habitat Metric 05/11/06 11/01/06 05/19/08 10/29/08 Average Channel Alteration 14 13 15 15 14 Bank Stability 16 12 14 10 13 Bank Vegetation 16 16 17 15 16 Embeddedness 8 14 14 11 12 Flow 16 18 16 15 16 Riffles 5 5 3 5 5 Riparian Vegetation 12 16 17 14 15 Pool Sediment 9 13 12 12 12 Epifaunal Substrate 16 16 14 13 15 Velocity 15 16 16 16 16

Total 127 139 138 126 133

Table 6.30 shows the habitat scores for the three benthic surveys at station

6BPOW179.20 in May and November 2006 and September 2008. Both the

Embeddedness metric and Pool Sediment metric were in the marginal category during the

fall 2006 survey indicating that excessive sediment is a periodic problem at this

monitoring station and the Pool Sediment metric scored in the marginal category again in

the fall of 2008. In addition, the average Riffles habitat metric score was in the marginal

category during both surveys indicating that some of the best habitat simply is limited.




Habitat Metric 04/20/06 10/16/06 09/25/08 Average Channel Alteration 13 14 15 14 Bank Stability 13 10 11 11 Bank Vegetation 10 10 11 10 Embeddedness 15 9 15 13 Flow 18 17 13 16 Riffles 13 7 10 10 Riparian Vegetation 12 8 11 10 Pool Sediment 14 11 9 11 Epifaunal Substrate 18 17 17 17 Velocity 18 14 16 16

Total 144 117 128 130

Table 6.31 shows the habitat scores for the four benthic surveys at station 6BPOW180.72

in November 1997, November 1998, June 1999 and December 2003. The Embeddedness

metric averaged in the marginal category and was in the poor category during the

November 1997 survey. The Pool Sediment metric also averaged in the marginal

category, indicating that excessive solids are a chronic problem at this monitoring station.

Bank Stability scores were in the marginal category indicating excessive stream bank

erosion which, contributes to in-stream sediment loads. The average total habitat score

was in the good category.



Total 114 120 132 126 123



Table 6.32 shows the habitat scores for the two benthic surveys at station 6BPOW184.19

in November 1997 and December 2003. The Embeddedness metric averaged in the

marginal category for both surveys and was in the poor category during the November

1997 survey. The Pool Sediment metric also averaged in the marginal category,

indicating that excessive solids are a chronic problem at this monitoring station. Bank

Stability scores were in the marginal category indicating excessive stream bank erosion

which, contributes to in-stream sediment loads.



Total 145

6.5.2 Habitat Assessment at Biological Monitoring Stations – North Fork Powell

River

Habitat assessment for the North Fork Powell River includes an analysis of habitat scores

recorded by the VADEQ biologist at the four VADEQ benthic monitoring stations. The

two VADEQ habitat assessments for VADEQ benthic monitoring station 6BPWL000.06

are shown in Table 6.33. The Pool Sediment habitat metric also scored in the marginal

category during both surveys indicating excessive sediment is a problem in this section of

the stream. The marginal Bank Stability scores indicate an excessive amount of stream

bank erosion that contributes to the overall sediment load in the stream. The Riffles

habitat metric also scored in the marginal category during both surveys indicating that

quality riffle habitat is very limited in this area of the stream.



Table 6.33 Habitat scores at VADEQ benthic monitoring station 6BPWL000.06 on the North Fork Powell River.


Total 128 132 130

Two VADEQ habitat assessments for VADEQ benthic monitoring station 6BPWL001.93

were performed in May and November 2006 and are shown in Table 6.34. The Pool

Sediment habitat metric also scored in the marginal category during the May 2006 survey

indicating that excessive sediment is a periodic problem in this section of the stream. The

Riffles habitat metric scored in the marginal category during both surveys indicating that

quality riffle habitat is very limited in this area of the stream.



Total 149 158 154

Four VADEQ habitat assessments for VADEQ benthic monitoring station 6BPWL004.40

were performed in the fall of 2003, spring of 2004 and spring and fall of 2008. The

results are shown in Table 6.35. The Embeddedness habitat metric scored in the marginal



category in the spring of 2008. The Pool Sediment habitat metric also scored in the

marginal category during fall 2003, spring 2004 and spring 2008 surveys indicating that

excessive sediment is periodically a problem in this section of the stream. The total

habitat scores were average at this monitoring station.



Total 131 132 130 122 129

Two VADEQ habitat assessments for VADEQ benthic monitoring station 6BPWL006.16

were performed in December 2003 and June 2004 and are shown in Table 6.36. The Pool

Sediment habitat metric also scored in the marginal category (very close to the poor

category) during the June 2004 survey indicating that excessive sediment is a periodic

problem in this section of the stream. Bank Stability scored in the marginal category

during both surveys indicating that the stream bank is badly eroded and contributing to

the overall sediment loading in the stream. The overall habitat scores were very good at

this monitoring station.





Total 137 142 140

6.5.3 Habitat Assessment at Biological Monitoring Stations – South Fork Powell

River

Habitat assessment for the South Fork Powell River includes an analysis of habitat scores

recorded by the VADEQ biologist at the four VADEQ benthic monitoring stations.

The VADEQ habitat assessment for VADEQ benthic monitoring station 6BPLL000.17 is

shown in Table 6.37. The habitat scores were mostly good.

Table 6.37 Habitat scores at VADEQ benthic monitoring station 6BPLL000.17 on the South Fork Powell River.


Total 151

The VADEQ habitat assessments for VADEQ benthic monitoring station 6BPLL001.61

are shown in Table 6.38. The fall and spring 2008 Pool Sediment scores were in the

marginal category as was the fall Embeddedness score and the Embeddedness habitat



metric scored in the marginal category in the fall of 2008. This indicates that excess

sediment was a problem at this monitoring station. Overall the total habitat scores for

both surveys were below average.



Total 105 115 110

The seven VADEQ habitat assessments for VADEQ benthic monitoring station

6BPLL002.55 are shown in Table 6.39. The Embeddedness habitat metric scored in the

marginal category during the November 1997 benthic survey and the Pool Sediment

habitat metric also scored in the marginal category during the November 1997 survey and

again in September 2007. This does indicate that excessive sediment is periodically a

problem at this benthic monitoring station. The average total habitat score is good.


Habitat Metric 04/18/96 11/20/97 8/31/98 05/22/07 09/18/07 Channel Alteration 15 17 17 16 17 Bank Stability 15 15 12 14 13 Bank Vegetation 18 18 18 9 13 Embeddedness 11 9 14 14 12 Flow 19 16 7 16 11 Riffles 17 16 12 10 14 Riparian Vegetation 12 8 13 10 10 Pool Sediment 15 8 12 11 7 Epifaunal Substrate 18 10 10 15 15 Velocity 17 9 11 12 10

Total 157 126 126 127 122



Table 6.39 Habitat scores at VADEQ benthic monitoring station 6BPLL002.55 on the South Fork Powell River (cont.).


Total 141 134 133

Table 6.40 shows the habitat scores for VADEQ benthic monitoring station

6BPLL004.49. There was one survey in August of 1998 and overall the habitat scores

represent a healthy condition.



Total 126

Table 6.41 shows the habitat scores for the one benthic survey at station 6BPLL006.38 in

August 1998. The overall habitat score at this monitoring station was very good.





Total 141

6.6 Discussion of In-stream Water Quality

This section provides an inventory of available observed in-stream water quality data

throughout the Powell River and North and South Fork Powell River watersheds. An

examination of data from water quality stations used in the Section 305(b) assessment

and data collected during TMDL development were analyzed. Sources of data and

pertinent results are discussed.

6.6.1 Inventory of Water Quality Monitoring Data

The primary sources of available water quality information for the Powell River and

North and South Fork Powell River are:

Data collected at VADEQ ambient monitoring stations, and

Special study fish tissue and sediment data collected at VADEQ stations.

Special study metals an toxics data collected at VADEQ stations

6.6.1.1 VADEQ Water Quality Monitoring – Powell River

VADEQ has monitored water quality consistently at three stations in the vicinity of the

three benthic monitoring stations on the impaired waters list on the Powell River (Table

6.42). The locations of these stations are shown in Figure 6.1. The conventional data is

summarized in Tables 6.43 through 6.45. Only data that exceeded the minimum

laboratory detection levels is shown.



Table 6.42 VADEQ ambient monitoring stations on the Powell River. Station Data Record River Mile

6BPOW138.91 03/1995 – 04/2008 138.91 6BPOW165.78 05/1992 – 02/2008 165.78 6BPOW179.20 05/1992 – 05/2008 179.20

Table 6.43 In-stream water quality data at 6BPOW138.91 in Powell River (3/1995 – 04/2008).

Water Quality Constituent Mean SD1 Max Min Median N2 Alkalinity (mg/L) 110 29 155 46 109 73 Ammonia + Ammonium (mg/L as N) 0.04 0.00 0.04 0.04 0.04 6 BOD5 (mg/L) 2.00 0.71 3.00 1.00 2.00 5 calcium, dissolved (mg/l) 26.60 NA 26.60 26.60 NA 1 Carbon, Total Organic (mg/l) 2.65 1.07 5.10 1.30 2.30 17 Chloride,Total (mg/L ) 7.23 2.71 17.60 2.70 6.60 53 COD (mg/L) 8.98 4.73 30.00 5.00 7.00 36 Conductivity (µmhos/cm) 447 116 716 238 448 132 DO_Probe (mg/L) 9.85 1.90 15.50 6.16 9.61 128 Field_pH (std units) 7.91 0.27 8.66 7.22 7.89 130 Hardness (mg/L As Caco3) 105.00 NA 105.00 105.00 NA 1 Magnesium, dissolved (mg/l) 9.40 NA 9.40 9.40 NA 1 Nitrate Nitrogen (mg/L as N) 0.65 0.25 1.20 0.14 0.64 96 Nitrite Nitrogen (mg/L) 0.01 0.01 0.05 0.01 0.01 24 Nitrite Plus Nitrate, Total (mg/L as N) 0.59 0.27 0.94 0.21 0.59 6 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.18 0.08 0.50 0.10 0.20 85 Nitrogen, Total (mg/L As N) 0.86 0.20 1.37 0.38 0.84 32 Phosphorus (Total Ortho P, mg/L) 0.02 0.01 0.03 0.01 0.02 74 Phosphorus, Total (mg/L As P) 0.02 0.01 0.06 0.01 0.02 125 Sulfate, Total (mg/L) 86 27 137 28 89 73 Temp_Celsuis 14.02 6.83 26.51 0.63 12.95 130 Total Dissolved Solids (mg/L) 264 74 474 136 262 85 Total Hardness (CaCO3 mg/L) 150 34 218 90 144 97 Total Inorganic Solids (mg/L) 226 58 341 118 224 96 Total Inorganic Suspended Solids (mg/L) 9.24 12.18 62.00 3.00 5.00 58 Total Organic Solids (mg/L) 45.06 14.32 87.00 12.00 43.00 96 Total Solids (mg/L) 288 74 457 147 285 122 Total Suspended Organic Solids (mg/L) 5.45 3.08 11.00 3.00 4.00 11 Total Suspended Solids (TSS) (mg/L) 9.63 12.28 73.00 3.00 5.00 87 Turbidity Lab (ntu) 8.47 17.78 98.00 0.83 3.30 37 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.




Water Quality Constituent Mean SD1 Max Min Median N2 Acidity, Total (mg/L) 3.15 0.79 4.00 2.45 3.00 3 Alkalinity (mg/L) 113 30 173 48 112 109 Ammonia + Ammonium (mg/L as N) 0.06 0.03 0.14 0.04 0.04 15 Bicarbonate, Watr, Diss. As Hco3 ,Mg/L 118.00 13.32 137 107 114.00 4 BOD5 (mg/L) 1.20 0.39 2.00 1.00 1.00 34 Calcium Ca (Total ug/L) 30,650 NA 30,650 30,650 NA 1 Calcium, dissolved (mg/L) 49.43 8.21 57 39 51.25 4 Carbon, Total Organic (mg/L) 2.52 1.25 6.50 1.00 2.20 49 Chloride, dissolved (mg/L) 7.59 1.86 9.82 6.05 7.24 4 Chloride,Total (mg/L ) 7.06 2.91 18.00 0.80 6.60 95 COD (mg/L) 7.80 3.75 25.50 2.00 7.00 59 Conductivity (µmhos/cm) 463 137 812 4 461 129 Dissolved Inorganic Solids (mg/L) 357 26 392 330 353 4 Dissolved Organic Solids (mg/L) 40.00 9.66 48 26 43.00 4 DO_Probe (mg/L) 10.49 2.07 17.05 6.86 10.57 122 Field_pH (std units) 7.90 0.30 8.46 7.12 7.92 124 Flouride (Total mg/L) 0.24 NA 0.24 0.24 NA 1 Hardness, Ca Mg (mg/L As Caco3) 147 27 174 110 159 5 Magnesium, Total (mg/l) 14,246 2,905 16,700 10,030 15,570 5 Magnesium, Dissolved (mg/l) 12.35 1.91 13.70 11.0 NA 2 Mangnese Mn (Total ug/L) 30.99 7.58 39.88 20.85 30.41 5 Nitrate Nitrogen (mg/L as N) 0.69 0.23 1.48 0.18 0.68 116 Nitrate Nitrogen, Dissolved (mg/L as N) 0.99 0.24 1.30 0.76 0.95 4 Nitrite Nitrogen (mg/L) 0.01 0.01 0.04 0.01 0.01 36 Nitrite Plus Nitrate, Total (mg/L as N) 0.85 0.29 1.27 0.25 0.83 9 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.20 0.08 0.40 0.10 0.20 108 Nitrogen, Total (mg/L As N) 1.01 0.26 1.34 0.39 1.06 10 Phosphorus (Total Ortho P, mg/L) 0.02 0.01 0.07 0.01 0.02 103 Phosphorus, Total (mg/L As P) 0.03 0.02 0.10 0.01 0.03 123 Potassium, Dissolved (mg/L) 2.80 0.47 3.17 2.14 2.94 4 Sodium, Dissolved (mg/L) 30.58 6.86 39 22 30.75 4 Sulfate, dissolved (mg/L) 180 13 196 164 181 4 Sulfate, Total (mg/L) 104 35 196 11 106 108 Tannin Lignin, ug/L 0.72 NA 0.72 0.72 NA 1 Temp_Celsuis 13.71 6.87 27.20 2.00 12.30 125 Total Dissolved Solids (mg/L) 285 84 550 125 279 109 Total Hardness (CaCO3 mg/L) 156 35 226 87 155 116 Total Inorganic Solids (mg/L) 250 70 391 128 242 120 Total Inorganic Suspended Solids (mg/L) 8.75 12.67 92.00 1.00 5.00 76 Total Organic Solids (mg/L) 47.52 15.61 100.00 15.00 45.00 119 Total Solids (mg/L) 297 78 449 154 292 120 Total Suspended Organic Solids (mg/L) 3.07 2.92 16.00 1.00 2.50 30 Total Suspended Solids (TSS) (mg/L) 9.37 13.35 108.00 1.00 6.00 95 Turbidity Lab (ntu) 16.03 33.67 118.00 0.62 3.00 13 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.




Water Quality Constituent Mean SD1 Max Min Median N2 Acidity, Total (mg/L) 3.26 1.34 5.50 1.48 3.38 12 Alkalinity (mg/L) 130 43 200 46 129 91 Ammonia + Ammonium (mg/L as N) 0.08 0.06 0.22 0.04 0.06 9 Bicarbonate, Watr, Diss. As Hco3 (Mg/L ) 175 15 195 156 174 5 BOD5 (mg/L) 1.51 0.92 5.00 1.00 1.00 35 Calcium Ca (Total ug/L) 36,130 1,372 37,100 35,160 NA 2 Calcium, dissolved (mg/l) 58 11 76 36 61.70 13 Carbon, Total Organic (mg/L) 2.32 1.62 7.80 0.93 1.75 40 Chloride, dissolved (mg/L) 5.78 0.51 6.21 5.22 5.91 3 Chloride,Total (mg/L ) 11 28 219 2 6 78 COD (mg/L) 7.63 4.10 19.00 1.80 6.40 48 Conductivity (µmhos/cm) 611 191 1,113 33 604 126Copper Cu (Total ug/L) 20.00 NA 20.00 20.00 NA 1 Dissolved Inorganic Solids (mg/L) 476 91 611 317 488 12 Dissolved Organic Solids (mg/L) 46 10 66 33 44.5 12 DO_Probe (mg/L) 10.80 1.79 15.70 7.70 10.76 99 Field_pH (std units) 8.12 0.31 8.80 6.84 8.16 125Flouride (Total mg/L) 0.15 0.05 0.26 0.07 0.13 21 Hardness, Ca Mg (mg/L As Caco3) 198 59 294 145 170 5 Magnesium (Total mg/L) 19,503 3,899 24,750 15,330 18,965 4 Magnesium, dissolved (mg/L) 29.78 6.69 42.10 20.00 30.60 13 Mangnese Mn (Total ug/L) 53 13 72 41 50.00 5 Nitrate Nitrogen (mg/L as N) 0.58 0.27 1.39 0.10 0.55 90 Nitrate Nitrogen, Dissolved (mg/L as N) 1.02 0.16 1.32 0.84 0.98 12 Nitrite Nitrogen (mg/L) 0.01 0.01 0.04 0.01 0.01 27 Nitrite Plus Nitrate, Total (mg/L as N) 0.92 0.24 1.35 0.29 0.96 30 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.18 0.14 1.00 0.10 0.10 83 Nitrogen, Total (mg/L As N) 1.05 0.24 1.58 0.39 1.06 33 Phosphorus (Total Ortho P, mg/L) 0.02 0.01 0.06 0.01 0.01 42 Phosphorus, Dissolved Ortho (mg/L As P) 0.03 0.06 0.24 0.01 0.01 17 Phosphorus, Total (mg/L As P) 0.03 0.04 0.30 0.01 0.02 101Potassium, Dissolved (mg/L) 4.07 0.67 4.98 2.97 4.13 12 Sodium, Dissolved (mg/L) 63 39 177 28 54 12 Sulfate, dissolved (mg/L) 276 27 306 253 262 5 Sulfate, Total (mg/L) 156 64 331 4 151 90 Temp_Celsuis 12.71 6.63 25.70 1.38 12.40 125Total Dissolved Solids (mg/L) 419 140 786 206 427 88 Total Hardness (CaCO3 mg/L) 188 50 285 98 190 90 Total Inorganic Solids (mg/L) 346 109 616 161 337 104Total Inorganic Suspended Solids (mg/L) 10 14 99 1 5.00 63 Total Organic Solids (mg/L) 57 24 180 20 53 104Total Solids (mg/L) 405 125 692 164 410 107Total Suspended Organic Solids (mg/L) 3.22 2.34 12.00 1.00 3.00 45 Total Suspended Solids (TSS) (mg/L) 11.20 15.41 112 1.00 5.50 90 Turbidity Lab (ntu) 12.08 23.25 110 1.50 4.59 34 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.



6.6.1.2 VADEQ Water Quality Monitoring– North Fork Powell River

VADEQ has monitored water quality recently at three sites in the vicinity of the impaired

benthic monitoring stations on the North Fork Powell River (Table 6.46). The location of

these stations is shown in (Figure 6.10). The data for this station is summarized in Table

6.47 through 6.49. Only data that exceeded the minimum laboratory detection levels is

shown.

Table 6.46 VADEQ ambient monitoring stations on the North Fork Powell River. Station Data Record River Mile

6BPWL001.49 1/1990 – 12/2006 1.49 6BPWL004.10 7/2003 – 1/2006 4.10 6BPWL006.59 8/2003 – 6/2005 6.59



Table 6.47 In-stream water quality data at 6BPWL001.49 on the North Fork Powell River (1/1990 – 12/2006).

Water Quality Constituent Mean SD1 Max Min Median N2

Acidity, Total (mg/L) 4.63 0.92 5.70 3.10 4.51 12Alkalinity (mg/L) 78 35 168 25 71 71Ammonia + Ammonium (mg/L as N) 0.09 0.04 0.17 0.04 0.09 23BOD5 (mg/L) 2.46 4.66 28.00 1.00 1.10 33Calcium Ca (Total ug/L) 21,870 NA 21,870 21,870 NA 1 Calcium, dissolved (mg/l) 29.80 5.94 38.10 20.80 31.10 12Carbon, Total Organic (mg/l) 1.90 0.83 5.10 1.00 1.80 37CBOD 60 Day, 20 Deg C 2.49 NA 2.49 2.49 NA 1 Chloride, dissolved (mg/L) 9.13 1.21 10.40 7.98 9.01 3 Chloride,Total (mg/L ) 5.53 3.06 12.30 1.14 5.20 62COD (mg/L) 5.87 3.22 14.70 1.00 5.20 43Conductivity (µmhos/cm) 375 154 807 130 334 85Dissolved Inorganic Solids (mg/L) 256 87 368 143 258 12Dissolved Organic Solids (mg/L) 23.33 8.79 42.00 12.00 22.50 12DO_Probe (mg/L) 10.25 2.11 14.89 6.82 10.18 61Field_pH (std units) 7.79 0.36 8.60 6.85 7.83 84Flouride (Total mg/L) 0.12 0.02 0.16 0.10 0.12 9 Hardness, Ca Mg (mg/L As Caco3) 117 37 156 70 115 6 Iron Fe (Total ug/L) 194 89 317 86 213 6 Magnesium (Total mg/L) 10,462 2,889 12,940 6,360 11,540 5 Magnesium, dissolved (mg/l) 11.21 2.76 15.20 7.22 10.95 12Mangnese Mn (Total ug/L) 58 36 113 19 57 6 Nitrate Nitrogen (mg/L as N) 0.43 0.18 0.97 0.18 0.39 60Nitrate Nitrogen, Dissolved (mg/L as N) 0.42 0.13 0.67 0.27 0.39 12Nitrite Nitrogen (mg/L) 0.02 0.01 0.04 0.01 0.01 22Nitrite Plus Nitrate, Total (mg/L as N) 0.41 0.12 0.73 0.26 0.37 24Nitrogen, Kjeldahl, Total, (mg/L As N) 0.20 0.09 0.50 0.10 0.20 66Nitrogen, Total (mg/L As N) 0.52 0.14 0.95 0.34 0.50 24Phosphorus (Total Ortho P, mg/L) 0.03 0.02 0.07 0.01 0.02 37Phosphorus, Dissolved Ortho (mg/L As P) 0.02 0.01 0.04 0.01 0.02 19Phosphorus, Total (mg/L As P) 0.04 0.02 0.10 0.01 0.03 74Potassium, Dissolved (mg/L) 2.22 0.75 3.34 1.27 2.04 12Sodium, Dissolved (mg/L) 42 23 78 12 41 12Sulfate, dissolved (mg/L) 111 31 135 58 114 5 Sulfate, Total (mg/L) 91 41 176 13 82 72Temp_Celsuis 13.31 6.54 24.20 1.80 12.80 85Total Dissolved Solids (mg/L) 252 95 410 92 235 48Total Hardness (CaCO3 mg/L) 123 43 210 58 113 60Total Inorganic Solids (mg/L) 206 89 395 81 180 72Total Inorganic Suspended Solids (mg/L) 6.56 7.29 34.00 1.00 4.50 34Total Organic Solids (mg/L) 34 13 75 12 33 72Total Solids (mg/L) 239 96 419 101 216 72Total Suspended Organic Solids (mg/L) 2.23 1.45 6.00 1.00 2.00 22Total Suspended Solids (TSS) (mg/L) 7.26 7.64 40.00 1.00 5.00 44Turbidity Lab (ntu) 3.45 2.85 14.00 0.84 2.64 241SD: standard deviation, 2N: number of sample measurements, NA not applicable.




Water Quality Constituent Mean SD1 Max Min Median N2 Calcium, dissolved (mg/l) 30.00 NA 30.00 30.00 NA 1 Conductivity (µmhos/cm) 452 197 985 232 428.5 14 DO_Probe (mg/L) 11.09 2.70 17.48 8.04 10.72 14 Field_pH (std units) 7.98 0.33 8.36 7.32 8.04 14 Hardness, Ca Mg Calculated (mg/L As Caco3)

124 NA 124 124 NA 1

Magnesium, dissolved (mg/l) 12.00 NA 12.00 12.00 NA 1 Nitrite Plus Nitrate, Total (mg/L as N) 0.19 0.07 0.32 0.09 0.20 11 Nitrogen, Total (mg/L As N) 0.31 0.06 0.43 0.22 0.29 12 Temp_Celsuis 12.71 7.44 22.20 0.60 13.10 14 Total Dissolved Solids (mg/L) 296 134 650 167 273 12 Total Suspended Solids (TSS) (mg/L) 4.67 0.58 5.00 4.00 5.00 3 Turbidity Lab (ntu) 3.03 1.31 5.80 1.30 3.20 12 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.


Water Quality Constituent Mean SD1 Max Min Median N2 Conductivity (µmhos/cm) 397 186 734 173 352 12 DO_Probe (mg/L) 10.55 1.79 13.58 8.13 10.24 12 Field_pH (std units) 8.03 0.30 8.57 7.55 8.07 12 Nitrite Plus Nitrate, Total (mg/L as N) 0.16 0.07 0.27 0.06 0.15 11 Nitrogen, Total (mg/L As N) 0.25 0.07 0.34 0.14 0.22 12 Phosphorus, Total (mg/L As P) 0.01 0.00 0.02 0.01 0.01 11 Temp_Celsuis 12.95 6.75 23.10 2.70 13.62 12 Total Suspended Solids (TSS) (mg/L) 5.00 2.65 8.00 3.00 4.00 3 Turbidity Lab (ntu) 3.71 2.90 12.00 1.30 3.15 12 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.

6.6.1.3 VADEQ Water Quality Monitoring– South Fork Powell River

VADEQ has monitored water quality recently at three sites in the vicinity of the impaired

benthic monitoring stations on the South Fork Powell River (Table 6.50). The location of

these stations is shown in Figure 6.15. The data for these stations are summarized in

Tables 6.51 through 6.53. Only data that exceeded the minimum laboratory detection

levels is shown.



Table 6.50 VADEQ ambient monitoring stations on the South Fork Powell River. Station Data Record River Mile

6BPLL000.27 08/2001 – 12/2007 0.27 6BPLL004.24 08/2001 – 12/2007 4.24 6BPLL006.38 6/1996 – 3/2001 6.38

Table 6.51 In-stream water quality data at 6BPLL000.27 on the South Fork Powell River (08/2001 – 12/2007).

Water Quality Constituent Mean SD1 Max Min Median N2 Conductivity (µmhos/cm) 217 60 305 118 228 16 Total Dissolved Solids (mg/L) 153 32 184 94 163 6 Total Solids (mg/L) 137 30 181 92 139 12 Total Inorganic Solids (mg/L) 104 30 145 61 103 12 Total Hardness (CaCO3 mg/L) 83 30 133 46 82 12 Total Organic Solids (mg/L) 33.4 16.6 76.0 13.0 31.5 12 Turbidity Lab (ntu) 8.4 7.6 26.0 2.0 6.7 9 Total Suspended Solids (TSS) (mg/L) 7.0 6.5 25.0 3.0 5 11 Temp_Celsuis 13.2 6.4 22.4 1.4 12.7 18 DO_Probe 10.9 1.9 14.3 8.5 10.6 16 Total Inorganic Suspended Solids (mg/L) 5.7 2.3 9.0 3.0 5 5

Field_pH 7.8 0.2 8.4 7.5 7.9 18 Nitrogen, Total (mg/L As N) 0.7 0.2 1.0 0.5 0.71 6 Nitrate Nitrogen (mg/L as N) 0.6 0.1 0.7 0.3 0.6 12 Nitrite Plus Nitrate, Total (mg/L as N) 0.6 0.1 0.7 0.4 0.5 6 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.2 0.1 0.4 0.1 0.1 10 Ammonia + Ammonium (mg/L as N) 0.17 NA 0.17 0.17 NA 1 Phosphorus, Total (mg/L As P) 0.02 0.01 0.05 0.01 0.02 18 Phosphorus (Total Ortho P, mg/L) 0.02 0.00 0.02 0.02 0.02 6 Nitrite Nitrogen (mg/L) 0.01 0.00 0.01 0.01 0.01 4 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.




Water Quality Constituent Mean SD1 Max Min Median N2 Ammonia + Ammonium (mg/L as N) 0.04 0.00 0.04 0.04 NA 2 Conductivity (µmhos/cm) 173 59 267 92 171 18 DO_Probe (mg/L) 10.73 1.71 14.50 8.60 10.11 17 Field_pH (std units) 7.86 0.23 8.20 7.50 7.87 18 Nitrate Nitrogen (mg/L as N) 0.42 0.13 0.59 0.22 0.39 12 Nitrite Nitrogen (mg/L) 0.01 0.00 0.01 0.01 0.01 5 Nitrite Plus Nitrate, Total (mg/L as N) 0.39 0.12 0.55 0.22 0.38 6 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.13 0.05 0.20 0.10 0.10 9 Nitrogen, Total (mg/L As N) 0.52 0.14 0.68 0.30 0.54 6 Phosphorus (Total Ortho P, mg/L) 0.02 0.00 0.02 0.02 0.02 5 Phosphorus, Total (mg/L As P) 0.02 0.01 0.04 0.01 0.01 17 Temp_Celsuis 13.22 6.24 23.72 2.30 13.19 18 Total Dissolved Solids (mg/L) 119 31 156 73 116 6 Total Hardness (CaCO3 mg/L) 59 31 119 18 51 12 Total Inorganic Solids (mg/L) 74 28 117 39 75 12 Total Inorganic Suspended Solids (mg/L) 4.40 1.52 6.00 3.00 4.00 5

Total Organic Solids (mg/L) 25 12 54 6 25 12 Total Solids (mg/L) 99 26 147 66 101 12 Total Suspended Solids (TSS) (mg/L) 5.50 4.12 16.00 3.00 3.50 10 Turbidity Lab (ntu) 6.05 5.22 17.00 1.40 4.70 9 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.




Water Quality Constituent Mean SD1 Max Min Median N2 Manganese Sediment (mg/kg) 306 4 309 303 NA 2 Conductivity (µmhos/cm) 89 34 149 43 80 29 Total Solids (mg/L) 58 21 105 27 54 28 Total Dissolved Solids (mg/L) 53 18 89 27 50 27 Total Inorganic Solids (mg/L) 41 17 75 7 37 28 Total Hardness (CaCO3 mg/L) 40 19 77 5 38 29 Alkalinity (mg/L) 32 15 62 13 25 29 Total Organic Solids (mg/L) 18 10 45 6 18 27 Temp_Celsuis 12.3 5.6 21.0 3.5 11.8 29 DO_Probe 10.5 1.5 14.4 7.9 10.2 29 COD (mg/L) 7.4 2.1 11.0 5.0 7.0 8 Sulfate, Total (mg/L) 7.2 1.4 11.2 5.5 7.2 29 Field_pH (std units) 7.2 0.3 8.0 6.7 7.2 29 Total Inorganic Suspended Solids (mg/L) 5.0 NA 5.0 5.0 NA 1 Total Suspended Solids (TSS) (mg/L) 3.8 1.6 8.0 3.0 3.0 9 Chloride,Total (mg/L ) 3.1 NA 3.1 3.1 NA 1 Carbon, Total Organic (mg/l) 1.7 0.3 1.9 1.5 NA 2 BOD5 (mg/L) 1.0 NA 1.0 1.0 NA 1 Nitrate Nitrogen (mg/L as N) 0.2 0.1 0.7 0.1 0.2 29 Nitrogen, Kjeldahl, Total, (mg/L As N) 0.1 0.0 0.2 0.1 0.1 24 Ammonia + Ammonium (mg/L as N) 0.04 NA 0.04 0.04 NA 1 Phosphorus (Total Ortho P, mg/L) 0.02 0.05 0.20 0.01 0.01 17 Nitrite Nitrogen (mg/L) 0.02 0.01 0.02 0.01 0.02 3 Phosphorus, Total (mg/L As P) 0.02 0.01 0.06 0.01 0.01 18 1SD: standard deviation, 2N: number of sample measurements, NA not applicable.

6.6.1.4 VADEQ Fish Tissue and Sediment Sampling Results – Powell River

VADEQ performed special fish tissue and sediment sampling at four sites in the Powell

River in 1997 and 2002 (Table 6.2 and Figure 1). All metals, pesticides and other

organic compounds were below VDH, VADEQ and EPA screening and action levels for

fish tissue and sediment at these four monitoring stations with the exception of 2-

Methylnaphthalene at station 6BPOW178.33, Table 6.54. The sediment values are

shown in Tables 6.55, 6.56 and 6.57. Sediment metals have also been periodically

collected at the three ambient monitoring sites since 1993 and at nine additional special

study monitoring stations on the Powell River. Tables 6.58 through 6.62 show the results

of these sampling events. Sediment organics have been collected at two of the ambient

monitoring stations (6BPOW165.78 and 6BPOW179.20) and three additional special

study monitoring stations on the Powell River, Tables 6.63 through 6.64. Only data that



exceeded the minimum laboratory detection levels are shown. Naphthalene, 2-

Methylnaphthalene and Heptachlor Epoxide exceeded established screening values at

several monitoring stations and Table 6.65 summarizes those results.

Table 6.54 Sediment metal sampling results from four VADEQ fish tissue monitoring stations on the Powell River.

Metal (mg/Kg)

PEC1, /VADEQ 99th Percentile

(mg/Kg)

6BPOW121.76 7/22/97 (mg/Kg)

6BPOW128.37 8/12/97 (mg/Kg)

6BPOW143.81 7/22/97 (mg/Kg)

6BPOW178.33 6/18/02 (mg/Kg)

Aluminum NA 0.78 0.49 1.10 0.36 Silver 2.60 0.03 0.06 0.09 <0.02 Arsenic 33 3.20 4.50 6.20 5.10 Cadmium 4.98 <0.01 0.14 <0.01 0.07 Chromium, Total 111 7.30 6.20 1.60 12.03

Copper 149 8.50 2.80 28.00 8.50 Mercury 1.06 0.10 0.09 0.27 0.02 Nickel 48.6 0.80 1.00 2.10 8.39 Lead 128 6.90 13.00 0.69 11.06 Antimony NA <0.5 <0.5 <0.5 <0.5 Selenium NA <0.5 <0.5 <0.5 <0.5 Thallium NA <0.3 <0.3 <0.3 <0.3 Zinc 459 66.00 51.00 116.00 14.15 1PEC = Probable Effect Concentration (McDonald, 2000) and VADEQ 99th percentile screening value, NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.55 Sediment polycyclic aromatic hydrocarbons (PAHs) results from four VADEQ fish tissue monitoring stations on the Powell River.

Parameter

PEC1, /VADEQ 99th Percentile

(ug/Kg)

6BPOW128.3708/12/97 (ug/Kg)

6BPOW121.7607/22/97 (ug/Kg)

6BPOW143.81 07/22/97 (ug/Kg)

6BPOW178.3306/18/02 (ug/Kg)

Total PAH2 22,800 2,508.58 3,226.87 14,162.26 991.45 High MW3 PAH NA 265.46 281.73 1,137.09 429.02 Low MW PAH NA 327.00 471.55 1,267.74 562.44 NAP4 561 119.53 125.99 300.74 49.16 NAP 2-Me5 83 112 NAP 1-Me7 NA 139.70 74.93 Biphenyl NA 19.05 62.16 14.37 NAP d-Me7 NA 92.35 98.73 297.94 61.37 ace-naphthylene 121 23.14 30.00 88.14 0.45 ace-naphthene 170 7.73 NAP t-Me8 NA 77.23 74.32 301.19 35.56 Fluorene 536 24.27 29.78 108.86 7.11 PHH9 1,170 141.11 254.47 686.10 137 ATH10 845 18.95 31.31 83.91 5.44 PHH 1-Me NA 167.30 245.71 889.50 57.62 FTH11 2,230 72.97 97.85 224.94 42.24 Pyrene 1,520 62.28 71.58 241.67 42.96 ATH benz(a) 1,050 38.01 26.87 378.91 30.08 Chrysene 1,290 70.42 59.60 189.73 53.64 FTH benzo(b) NA 17.85 24.34 87.10 49.13 FTH benzo(k) NA 13.90 47.35 29.50 Pyrene benzo(e) NA 25.38 27.30 93.59 54.28 Pyrene benzo(a) 1,450 21.78 25.83 73.86 46.67 Perylene NA 12.21 75.20 7.15 Pyrene IND12 NA 15.87 32.16 21.45 ATH db(a,h)13 318 27.99 16.22 Perylene benzo(ghi) NA 18.53 63.50 35.71 1PEC = Probable Effect Concentration (McDonald, 2000) and VA 99th percentile – VADEQ screening value, 2PAH = Polyaromatic hydrocarbon, also polynuclear aromatic hydrocarbons (PNAs), 3MW = Molecular Weight, 4NAP = Naphthalene, 52-Methyl Napthalene, 61-Me Methyl, 72,6-Dimethyl, 82,3,5-Trimethyl, 9PHH = Phenanthrene, 10Anthracene, 11FTH = Fluoranthene, 12indeno(1,2,3-cd) 13db(a,h) dibenzo(a,h), NA = None specified, all values are in parts per billion ug/Kg dry weight basis dry weight basis (ppb), Bold values exceed a screening value.



Table 6.56 Sediment polychlorinated biphenyls (PCBs) and pesticide results from VADEQ fish tissue monitoring stations on the Powell River.

Parameter PEC1, (ug/Kg)

6BPOW121.7607/22/97 (ug/Kg)

6BPOW128.3708/12/97 (ug/Kg)

6BPOW143.81 07/22/97 (ug/Kg)

6BPOW178.3306/18/02 (ug/Kg)

Total PCB2 676 0.76 0.16 11.98 2.56 Total3 Chlordane 17.6 1.38 0.73 Sum DDE4 31.3 0.13 Sum DDD5 28 Sum DDT6 62.9 0.30 0.79 0.36 Total7 DDT 572 0.30 0.79 0.49 Total BDE8 NA 4.43 HCB9 NA 0.03 Heptachlor Epoxide 16 PCA10 NA 0.14 Gamma BHC 4.99 Total BHC 4.99 OCDD11 NA 0.07 Endrin 207 Endrin Aldehyde 207 * cpd 112 NA 0.25 1PEC = Probable Effect Concentration (McDonald, 2000), 2Total PCB = sum of polychlorinated biphenyl congeners, 3Total Chlordane denotes sum of chlordane and breakdown products, 4sum DDE denotes sum of dichlorodiphenyl dichloroethylene isomers, 5sum DDD denotes sum of dichlorodiphenyl dichloroethane isomers, 6sum DDT denotes sum of dichlorodiphenyl trichloroethane isomers, 7Total DDT denotes sum of isomers of DDE, DDD, and DDT, 8Total BDE denotes sum of polybrominated diphenyl ether congeners, 9Hexachlorobenzene, 10Pentachloroanisole, 11Octachlorodibenzodioxin, 12cpd-1 denotes compound 1; Methoxytriclosan, NA = None specified and all values are in parts per billion ug/Kg dry weight basis dry weight basis (ppb).

Table 6.57 Special study sediment metals results from VADEQ ambient monitoring station 6BPOW138.91 on the Powell River.

Parameter (mg/Kg) PEC1 (mg/Kg)07/17/95(mg/Kg)

07/01/96 (mg/Kg)

05/06/97 (mg/Kg)

05/05/99 (mg/Kg)

Aluminum NA 4,050 6,220 22,779 10,100 Antimony NA 5 5 Arsenic 33 6 5 Chromium, Total 111 7 11 23 15.8 Copper 149 9 15 26 29.9 Iron NA 336 449 1,556 706 Lead 128 12 19 25 21.9 Manganese NA 12,800 14,700 29,640 20,800 Nickel, total 48.6 16 19 39 27.4 Selenium NA 1.41 1.2 Zinc 459 56 76 160 93.5 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).





06/03/93 (mg/Kg)

06/29/94 (mg/Kg)

07/17/95 (mg/Kg)

10/02/95(mg/Kg)

Aluminum NA 5,340 5,840 5,239 Antimony NA 5 6.7 10 Arsenic 33 Chromium, Total 111 9 14 10 8.7 10 Copper 149 12 27 17 14.5 12 Iron NA 13,300 13,818 13,400 Lead 128 11 21 14 43 18 Manganese NA 400 410 330 Nickel, total 48.6 19 32 16 17.4 15 Selenium NA 1 Zinc 459 59 130 57 80 59 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

Table 6.58 Special study sediment metals results from VADEQ ambient monitoring station 6BPOW165.78 on the Powell River (cont).


05/06/97(mg/Kg)

05/05/99(mg/Kg)

Aluminum NA 7,910 10,373 8,100 Antimony NA Arsenic 33 5 5 Chromium, Total 111 12 14 14.9 Copper 149 18 22 23.9 Iron NA 17,800 19,954 18,200 Lead 128 18 20 17.6 Manganese NA 788 982 641 Nickel, total 48.6 22 27 19 Selenium NA 1.1 Zinc 459 106 99 70.8 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).





03/20/91 (mg/Kg)

08/03/92 (mg/Kg)

06/23/93 (mg/Kg)

06/29/94(mg/Kg)

Aluminum NA 7,070 Arsenic 33 4 6 Chromium, Total 111 8 6 15 13 12 Copper 149 16 10 20 26 25 Iron NA 16,800 Lead 128 13 10 14 19 16 Manganese NA 529 Mercury 1.06 Nickel, total 48.6 13 13 24 26 22 Selenium NA 4 Zinc 459 41 41 86 100 88 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

Table 6.59 Special study sediment metals results from VADEQ ambient monitoring station 6BPOW179.20 on the Powell River (cont).

Parameter (mg/Kg)

PEC1, /VADEQ 99th

Percentile (mg/Kg)

08/16/95(mg/Kg)

08/05/96(mg/Kg)

05/06/97(mg/Kg)

05/05/99 (mg/Kg)

Aluminum NA 17,900 8,730 8,825 5,980 Silver 2.6 Arsenic 33 12 7 Cadmium 4.98 Chromium, Total 111 23 14 12 11.8 Copper 149 38 37 22 25.6 Mercury 1.06 Nickel, total 48.6 49 40 27 20 Lead 128 33 27 18 24.7 Antimony NA 30 Selenium NA 1 2 1.3 1 Thallium NA Zinc 459 132 145 89 72.1 Manganese NA 1,500 1,770 1,093 662 Iron NA 30,500 25,100 18,327 18,800 1PEC = Probable Effect Concentration (McDonald, 2000) and VADEQ 99th percentile screening value, NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.60 Sediment metals results from four VADEQ special study monitoring stations on the Powell River.

Parameter (mg/Kg)

PEC1 (mg/Kg)

6BPOW123.6404/28/05 (mg/Kg)

6BPOW128.3707/31/91 (mg/Kg)

6BPOW133.0005/01/03 (mg/Kg)

6BPOW133.00 04/08/04 (mg/Kg)

6BPOW141.4505/01/03 (mg/Kg)

Aluminum NA 5,750 5,340 1,740 3,410 Cadmium 4.98 1.0 Chromium, Total

111 9.35 11 9.4 5

Copper 149 11.8 12 7.4 Iron NA 15,400 13,600 8,420 10,800 Lead 128 14.83 8.9 5.85 7.7 Manganese NA 493 368 240 226 Nickel, total 48.6 15.67 13 12.3 8.31 8.8 Zinc 459 55.78 70 47.3 36.2 36.1 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

Table 6.61 Sediment metals results from VADEQ special study monitoring station 6BPOW143.53 on the Powell River.

Parameter (mg/Kg) PEC

(mg/Kg)103/07/90 (mg/Kg)

04/16/91 (mg/Kg)

07/09/92 (mg/Kg)

06/03/93 (mg/Kg)

05/23/94(mg/Kg)

Arsenic 33 6 5 Chromium, Total 111 16 9 13 10 6 Copper 149 30 22 24 17 18 Lead 128 24 13 23 19 11 Nickel, total 48.6 25 17 28 20 15 Thallium NA 5 Zinc 459 84 51 106 71 44 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

Table 6.62 Sediment metals results from four VADEQ special study monitoring stations on the Powell River.

Parameter (mg/Kg)

PEC, (mg/Kg)1

6BPOW156.5710/22/01 (mg/Kg)

6BPOW162.8904/30/07 (mg/Kg)

6BPOW170.76 03/29/05 (mg/Kg)

6BPOW184.1904/10/07 (mg/Kg)

Aluminum NA 2,080 3,483 6,760 9,840 Arsenic 33 5.99 Chromium, Total 111 6.13 10.5 13.6 Copper 149 7.46 17.3 20.9 Iron NA 13,400 12,300 18,200 29,100 Lead 128 9.7 9.92 18.1 17.9 Manganese NA 299 363 598 2840 Nickel, total 48.6 8.7 10.8 19.9 34.3 Selenium NA 1.92 Zinc 459 29.2 40.5 113 114 1PEC = Probable Effect Concentration (McDonald, 2000), NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.63 Special study sediment organics results from twoVADEQ ambient monitoring stations on the Powell River.

Parameter (ug/Kg) PEC1

(ug/Kg)

VA 99th Percentile2

(ug/Kg)

6BPOW165.7806/29/94 (ug/Kg)

6BPOW179.20 06/29/94 (ug/Kg)

6BPOW179.2001/26/06 (ug/Kg)

1,4-DIMETHYL NAPTHALENE

886

1-METHYL PHENANTHRENE

0.535

1-Methylnaphthalene 1.802 2,3,5-TRIMETHYL NAPHTHALENE

546

2,6-Dimethylnaphthalene 1,028

2-Methylanthracene 517 2-Methyl Napthalene 83 1,400 3,6-DIMETHYL PHENANTHRENE

155

9,10-DIMETHYL ANTHRACENE

31

Acenaphthene 170 44 Aldrin 55 50 B2E PHTH 151 Benzo[a]anthracene 1,050 232 Benzo[a]pyrene 1,450 116 Benzo[b]fluoranthene 128 BIPHENYL 197 BTLBNZY LPHTHALAT 62 BZO(GHI)PERYLENE 56 CDANEDRYTECH and MET

50 45

Chrysene 1,290 329 DDD 28 50 45 DDE 31.3 50 45 DDT 62.9 45 40 DETHPHTH 27.4 Dibenz[a,h]anthracene 318 19.9 DICOFOL 100 100 Dieldrin 61.8 55 50 DINOCTPH 10 DNB PHTH 110 Endrin Aldehyde 85 75 Fluoranthene 2,230 499 Fluorene 536 102 Heptachlor Epoxide 16 55 50 Heptachlor 45 40 Indeno[1,2,3-cd]pyrene 1,450 73.40 METHYL FLUORENE 170 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.63 Special study sediment organics results from twoVADEQ ambient monitoring stations on the Powell River (cont).


(ug/Kg)

6BPOW165.78 06/29/94 (ug/Kg)

6BPOW179.20 06/29/94 (ug/Kg)

6BPOW179.2001/26/06 (ug/Kg)

Naphthalene 561 942 PCB 105 52.47 PCB 116 + 125 0.05 PCB 128 64.00 PCB 129 0.05 PCB 130 0.05 PCB 131 + 146 0.05 PCB 132 + 153 0.35 PCB 135 + 144 0.05 PCB 137 0.05 PCB 138 + 158 0.14 PCB 139 0.05 PCB 141 50.00 PCB 149 0.05 PCB 151 54.65 PCB 156 50.00 PCB 157 0.05 PCB 163 + 164 0.06 PCB 167 0.05 PCB 170 + 190 0.08 PCB 171 0.05 PCB 172 0.05 PCB 174 0.06 PCB 175 0.05 PCB 176 0.05 PCB 177 0.05 PCB 178 0.05 PCB 179 0.05 PCB 180 + 193 0.17 PCB 183 50.00 PCB 185 0.05 PCB 187 66.80 PCB 194 0.05 PCB 195 50.00 PCB 196 + 203 0.06 PCB 199 0.06 PCB 200 0.05 PCB 201 0.05 PCB 202 0.05 PCB 206 118 PCB 3 0.10 PCB 77 192 1PEC = Probable Effect Concentration (McDonald, 2000), A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.63 Special study sediment organics results from twoVADEQ ambient monitoring stations on the Powell River (cont).


(ug/Kg)

6BPOW165.7806/29/94 (ug/Kg)

6BPOW179.20 06/29/94 (ug/Kg)

6BPOW179.2001/26/06 (ug/Kg)

PCB 82 0.05 PCB 83 0.05 PCB 85 + 110 + 120 0.89 PCB 86 + 97 0.05 PCBS, Total 676 15 3.069 PCBS Total (Isomer Analyses) 15 PCP (PENTACHLOROPHENOL) 100 100 Perylene 36.10 Phenanthrene 1,170 1,048 Pyrene 1,520 426 Toxaphene 490 430 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.64 Special study sediment organics results from four VADEQ special study monitoring stations on the Powell River.

Parameter

PEC1 (ug/Kg)/ VA 99th

Percentile (ug/Kg)

6BPOW123.6404/28/05 (ug/Kg)

6BPOW133.0001/14/04 (ug/Kg)

6BPOW141.45 01/14/04 (ug/Kg)

6BPOW170.7603/29/05 (ug/Kg)

2-Methyl Napthalene 83 1,279.3 10 1,822.8 2,4-DB 10 10 3,5-DCBA 10 ACIFLUORFEN (BLAZER) 10 10 AENDOSUL 1 1 ALPHA-CHLORDANE 2 AMIBEN (CHLORAMBEN) 10 10 B2E PHTH 762.4 180.2 BENTAZON 10 36 10 Benzo[a]anthracene 1,050 103.9 Benzo[a]pyrene 1,450 77.9 112.9 Benzo endosulfan 2 Benzo[b]fluoranthene 72.9 28 120.85 BTLBNZY LPHTHALAT 91.3 104.2 BZO(GHI)PERYLENE 63.7 83.2 Chrysene 1,290 167.6 35 DCPA(DACTHAL) 10 10 DETHPHTH 28.5 DICAMBA, 10 DICHLOROPHENOXYACETIC ACID,2,4- 10 10

DICHLORPROP 10 10 DNB PHTH 403 Fluoranthene 2,230 85.5 60 273.5 Fluorene 536 51.1 GAMMA-CHLORDANE 2 MCPA 10 10 MCPP 10 10 I123CDPR 41.9 Naphthalene 561 1110.9 1,439 PCB 105 51.45 PCB 136 100 PCB 151 2 PCB 157 0.123 PCB 170 + 190 0.199 PCB 171 0.050 PCB 172 0.050 PCB 177 0.141 PCB 180 + 193 0.445 PCB 187 137.58 1PEC = Probable Effect Concentration (McDonald, 2000) and VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.64 Special study sediment organics results from four VADEQ special study monitoring stations on the Powell River (cont).

Parameter PEC1

(ug/Kg)

6BPOW123.6404/28/05 (ug/Kg)

6BPOW133.0001/14/04 (ug/Kg)

6BPOW141.45 01/14/04 (ug/Kg)

6BPOW170.7603/29/05 (ug/Kg)

PCB 191 361.33 PCB 195 50 PCB 196 + 203 281.36 PCB 200 50 PCB 201 50 PCB 206 51.56 192.63

PCP (PENTACHLOROPHENOL) 10 10

Phenanthrene 1,170 762.4 32 Pyrene 1,520 119 64 207

PICLORAM,RECOVERABLE 10 10

SILVEX 10 10 TRICHLOROPHENOXYACETIC,2,4,5- ACD 10 10 1PEC = Probable Effect Concentration (McDonald, 2000), A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).

Table 6.65 Summary of sediment organic compounds that exceeded screening

values at VADEQ Powell River monitoring stations. Station Date Parameter Screening Value

(ug/Kg) Value (ug/Kg)

6BPOW165.78 6/29/1994 Heptachlor Epoxide 16 55 6BPOW179.20 6/29/1994 Heptachlor Epoxide 16 50 6BPOW178.33 6/18/2002 2-Methyl Napthalene 83 112 6BPOW170.76 3/29/2005 2-Methyl Napthalene 83 1,823 6BPOW170.76 3/29/2005 Napthalene 561 1,439 6BPOW123.64 4/28/2005 2-Methyl Napthalene 83 1,279 6BPOW123.64 4/28/2005 Napthalene 561 1,111 6BPOW179.20 1/26/2006 2-Methyl Napthalene 83 1,400 6BPOW179.20 1/26/2006 Napthalene 561 942

6.6.1.5 Dissolved Metals Sampling Results – Powell River

Dissolved metals were collected at two VADEQ ambient monitoring stations and eight

additional special study monitoring stations on the Powell River and all of the values

were below the chronic water quality standard. The results are shown in Tables 6.66

through 6.69. Only data that exceeded the minimum laboratory detection levels is shown.



Table 6.66 Dissolved metal concentrations at two VADEQ ambient monitoring stations on the Powell River.

Metal

6BPOW138.9105/13/02 (ug/L)

Chronic WQS1 (ug/L)

6BPOW179.20 08/12/03 (ug/L)

Chronic WQS1 (ug/L)

Antimony 0.13 NA Aluminum 37 NA 0.34 NA Arsenic 0.49 NA Barium 69 NA Chromium (III) 1.17 500.74 Copper 0.42 12.34 0.98 29.72 Manganese 15.7 NA 12.4 NA Nickel 0.61 21.21 2.51 50.63 Selenium 0.7 NA 2.33 NA Zinc 1.35 264.36 1WQS = VADEQ water quality standard. WQS are based on formulas dependent on the hardness at the time of sampling, N/A = Not Applicable, there is no chronic water quality standard for this metal and all values in parts per billion ug/Kg dry weight basis (ppb).

Table 6.67 Dissolved metal concentrations at two VADEQ special study monitoring stations on the Powell River.

Metal

6BPOW123.6404/28/05 (ug/L)

Chronic WQS1 (ug/L)

6BPOW141.45 05/01/03 (ug/L)

Chronic WQS1 (ug/L)

Aluminum 17.9 NA 31 NA Arsenic 0.2 NA 0.17 NA Barium 26.9 NA 36 NA Chromium (III) 0.24 270.15 Copper 0.47 8.97 0.6 15.61 Manganese 3.7 NA 5.35 NA Nickel 0.53 15.47 1.19 26.77 Selenium 0.74 NA Zinc 1.70 80.63 1WQS = VADEQ water quality standard. WQS are based on formulas dependent on the hardness at the time of sampling, N/A = Not Applicable, there is no chronic water quality standard for this metal and all values in parts per billion ug/Kg dry weight basis (ppb).



Table 6.68 Dissolved metal concentrations at VADEQ special study monitoring station 6BPOW133.00 on the Powell River.

Metal 04/08/04 (ug/L)

Chronic WQS1 (ug/L)

05/01/03 (ug/L)

Chronic WQS1 (ug/L)

Aluminum 25 NA 31 NA Antimony 0.14 NA Arsenic 0.27 NA 0.27 NA Barium 26 NA 38 NA Chromium (III) 0.34 252.87 0.39 282.68 Copper 0.51 14.57 Manganese 4.97 NA 9.1 NA Nickel 0.97 25.00 1.14 28.05 Selenium 0.86 NA 1.06 NA Zinc 2.34 146.32 1WQS = VADEQ water quality standard. WQS are based on formulas dependent on the hardness at the time of sampling, N/A = Not Applicable, there is no chronic water quality standard for this metal and all values in parts per billion ug/Kg dry weight basis (ppb).

Table 6.69 Dissolved metal concentrations at three VADEQ special study monitoring stations on the Powell River.

Metal

6BPOW162.89 04/30/07 (ug/L)

Chronic WQS1 (ug/L)

6BPOW170.7603/29/05 (ug/L)

Chronic WQS1 (ug/L)

6BPOW184.19 04/10/07 (ug/L)

Chronic WQS1 (ug/L)

Aluminum 18.2 17.5 NA 9.3 NA Arsenic 0.2 NA 0.2 NA 0.2 NA Barium 43.9 NA 36.5 NA 33.1 NA Chromium (III) 0.5 414.69 0.2 298.67 0.4 496.46

Copper 0.7 24.41 0.6 17.33 0.6 29.46 Manganese 15.5 NA 32.5 NA 36.9 NA Nickel 1.3 41.67 1 29.69 2.9 50.18 Selenium 2.3 NA 1.1 NA 2.1 NA Zinc 1.9 217.52 2 154.89 1.6 262.03 1WQS = VADEQ water quality standard. WQS are based on formulas dependent on the hardness at the time of sampling, N/A = Not Applicable, there is no chronic water quality standard for this metal and all values in parts per billion ug/Kg dry weight basis (ppb).

6.6.1.6 Fish Tissue and Sediment Sampling Results – North Fork Powell River

VADEQ performed special fish tissue sampling at two sites on the North Fork Powell

River. A Stoneroller minnow at monitoring station 6BPWL001.62 had an Arsenic

concentration of 3.6 ppm (parts per million), which was higher than the VADEQ

screening value of 0.072 ppm. A fish consumption advisory has not been issued by the

VDH. All other fish tissue concentrations were below VDH levels of concern and/or

VADEQ screening levels. All sediment values, collected at the fish tissue monitoring



stations, for metals, PCBs, pesticides and other polynuclear araomatic hydrocarbons

(PAHs) were below consensus PEC values, Tables 6.70 through 6.73. Sediment metals

and organics were also collected at two VADEQ ambient monitoring stations on the

North Fork Powell River, Tables 6.74 through 6.75. Only data that exceeded the

minimum laboratory detection levels is shown. Naphthalene and 2-Methylnaphthalene

exceeded established screening values at VADEQ monitoring stations 6BPWL001.49 and

6BPWL004.10 and Table 6.76 summarizes those results.

Table 6.70 Special study sediment metal sampling results at VADEQ fish tissue monitoring stations on the North Fork Powell River.

Metal

PEC1, /VADEQ 99th

Percentile (mg/Kg)

6BPWL001.62 08/13/97 (mg/Kg)

6BPWL002.48 06/18/02 (mg/Kg)

Aluminum NA 0.56 0.65 Silver 2.6 0.15 <0.02 Arsenic 33 3.80 5.62 Cadmium 4.98 1.70 0.27 Chromium, Total 111 6.30 12.71 Copper 149 6.50 27.51 Mercury 1.06 0.28 0.05 Nickel, total 48.6 1.40 21.05 Lead 128 9.60 21.91 Antimony NA <0.5 <0.5 Selenium NA <0.5 <0.5 Thallium NA <0.3 <0.3 Zinc 459 73.00 65.66 1PEC = Probable Effect Concentration (McDonald, 2000) and VADEQ 99th percentile screening value, NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.71 Special study PCB and pesticide results at VADEQ fish tissue monitoring stations on the North Fork Powell River.

Parameter PEC1 (ug/Kg)

6BPWL001.6208/13/97 (ug/Kg)

6BPWL002.4806/18/02 (ug/Kg)

Total PCB2 676 5.73 10.50 Total3 Chlordane 17.6 0.38 1.51 Sum DDE4 31.3 0.76 0.20 Sum DDD5 28 0.07 Sum DDT6 62.9 0.12 1.27 Total7 DDT 572 0.88 1.54 Total BDE8 NA 0.41 6.37 HCB9 NA 0.09 Heptachlor NA 0.04 Heptachlor epoxide 16 0.02 0.08 PCA10 NA 0.11 alpha BHC11 NA beta BHC NA delta BHC NA 0.03 gamma BHC 4.99 Total BHC 4.99 Total PCT12 NA Mirex NA OCDD13 NA 0.02 0.16 Methoxy~ chlor NA Cl-NAP14 NA 0.15 Aldrin NA Permethrin NA Dicofol NA Endrin 207 Endrin Aldehyde 207 TriBA15 NA TetCAN16 NA TetCB17 NA TriCB18 NA DDMU19 NA DDMS20 NA PCT21 A-5460 NA cpd 122 NA 0.34 cpd 223 NA cpd 324 NA cpd 425 NA 1PEC = Probable Effect Concentration (McDonald, 2000), 2Total PCB = sum of polychlorinated biphenyl congeners, 3Total Chlordane denotes sum of chlordane and breakdown products, 4sum DDE denotes sum of dichlorodiphenyl dichloroethylene isomers, 5sum DDD denotes sum of dichlorodiphenyl dichloroethane isomers, 6sum DDT denotes sum of dichlorodiphenyl trichloroethane isomers, 7Total DDT denotes sum of isomers of DDE, DDD, and DDT, 8Total BDE denotes sum of polybrominated diphenyl ether congeners, 9Hexachlorobenzene, 10Pentachloroanisole, 11Benzene hexachloride ( also hexachlorocyclohexane - HCH, gamma BHC is Lindane), 12Total Polychlorinated terphenyl compounds, 13Octachlorodibenzodioxin, 142-Chloronaphthalene, 15Tribromoanisole -MS, 16Tetrachloroaniline -MS, 17Tetrachlorobenzene -MS, 18Trichlorobenzene, 191-Chloro-2,2-bis-(4'-chlorophenyl)ethylene (metabolite of DDT), also DDD-olefin,



201-Chloro-2,2-bis-(4'-chlorophenyl)ethane (metabolite of DDT), 21PCT Aroclor 5460, 22cpd-1 denotes compound 1; Methoxytriclosan, 23cpd-2 denotes compound 2; C13H10Cl2O-triclosan derivative, 24cpd-3 denotes compound 3; Trichlorodimethylmethoxybenzene, 25cpd-4 denotes compound 4; MW 315 Unidentified halogenated cpd, NA = None specified and all values are in parts per billion ug/Kg dry weight basis dry weight basis (ppb).

Table 6.72 Special study PAH results at VADEQ fish tissue monitoring stations

on the North Fork Powell River.

Parameter

PEC1 (ug/Kg)/VA 99th

Percentile

6BPWL001.62 08/13/97 (ug/Kg)

6BPWL002.4806/18/02 (ug/Kg)

Total PAH2 22,800 6,010 4,242 High MW3 PAH NA 598.49 3,073 Low MW PAH NA 1,061 1,169 NAP4 561 479.94 131.96 NAP 2-Me5 83 234.94 NAP 1-Me6 NA 8.79 167.04 biphenyl NA 40.25 17.83 NAP d-Me7 NA 202.53 111.56 Naphthylene ace~ 121 81.98 3.45 naphthene ace~ 170 10.58 NAP t-Me8 NA 218.15 77.86 fluorene 536 45.25 16.42 PHH9 1,170 406.98 260.86 ATH10 845 46.36 24.03 PHH 11-Me NA 359.14 112.42 FTH12 2,230 223.24 368.54 Pyrene 1,520 177.92 331.75 ATH benz(a) 1,050 57.90 259.45 chrysene 1,290 84.67 255.95 FTH benzo(b) NA 56.21 342.94 FTH benzo(k) NA 28.73 237.01 Pyrene benzo(e) NA 52.10 270.50 Pyrene benzo(a) 1,450 45.72 368.64 perylene NA 16.51 87.83 Pyrene IND13 NA 33.13 218.24 ATH db(a,h)14 318 9.04 82.22 perylene benzo(ghi) NA 42.39 249.91 1PEC = Probable Effect Concentration (McDonald, 2000) and VA 99th percentile – VADEQ screening value, 2PAH = Polyaromatic hydrocarbon, also polynuclear aromatic hydrocarbons (PNAs), 3MW = Molecular Weight, 4NAP = Naphthalene, 52-Methyl Napthalene, 61-Me Methyl, 72,6-Dimethyl, 82,3,5-Trimethyl, 9PHH = Phenanthrene, 10Anthracene, 11 Methyl Phenanthrene, 12FTH = Fluoranthene, 13indeno(1,2,3-cd) 14db(a,h) dibenzo(a,h), NA = None specified and all values are in parts per billion ug/Kg dry weight basis dry weight basis (ppb).



Table 6.73 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River.

Metal PEC1,

(mg/Kg) 04/03/90 (mg/Kg)

03/20/91 (mg/Kg)

07/09/92 (mg/Kg)

06/23/93 (mg/Kg)

Aluminum NA Arsenic 33 7 8 Chromium, Total 111 32 13 10 25 Copper 149 35 23 14 39 Nickel, total 48.6 50 36 31 68 Lead 128 20 25 10 37 Antimony NA Selenium NA 5 12 Zinc 459 154 110 74 240 1PEC = Probable Effect Concentration (McDonald, 2000), , NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

Table 6.73 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River (cont).

Metal PEC1

(mg/Kg) 10/31/94 (mg/Kg)

10/02/95 (mg/Kg)

08/27/96 (mg/Kg)

06/11/97 (mg/Kg)

Aluminum NA 4,370 2,600 5,030 6,252 Arsenic 33 10 Chromium, Total 111 7 6 8 8 Copper 149 12 8 13 11 Nickel, total 48.6 15 11 19 18 Lead 128 31 9 9 7 Antimony NA 8 Selenium NA Zinc 459 55 38 62 59 1PEC = Probable Effect Concentration (McDonald, 2000), , NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.73 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River (cont).

Metal PEC1 06/22/98 (mg/Kg)

08/24/99 (mg/Kg)

01/26/06 (mg/Kg)

Aluminum NA 13,600 20,100 5,410 Arsenic 33 6.98 7.3 Chromium, Total 111 14.43 30.9 10.1 Copper 149 27.76 21.1 15 Nickel, total 48.6 44.67 33.4 20.5 Lead 128 33.72 19.6 13 Antimony NA Selenium NA 1.07 Zinc 459 201 77.4 71 1PEC = Probable Effect Concentration (McDonald, 2000), , NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).



Table 6.74 Special study sediment organics results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River (01/26/2006).

Parameter PEC1 (ug/Kg)Va 99th percentile2

(ug/Kg) (ug/Kg) 1-METHYL PHENANTHRENE 0.27 1-Methylnaphthalene 1.40 2,3,5-TRIMETHYL NAPHTHALENE

210

2,6-Dimethylnaphthalene 560 2-Methylanthracene 138 2-Methyl Napthalene 83 1,067 3,6-DIMETHYL PHENANTHRENE

64.5

Acenaphthene 170 43.0 B2E PHTH 101 Benzo[a]anthracene 1,050 162 Benzo[a]pyrene 1,450 110 Benzo[b]fluoranthene 131 BIPHENYL 94.2 BTLBNZY LPHTHALAT 54.4 BZO(GHI)PERYLENE 48.7 Chrysene 263 DETHPHTH 23.4 Dibenz[a,h]anthracene 318 15.8 DNB PHTH 86.0 Fluoranthene 2,230 398 Fluorene 536 54.4 Indeno[1,2,3-cd]pyrene 1,450 68.3 METHYL FLUORENE 68.3 Naphthalene 561 933 PCB 101 1,251 PCB 105 475 PCB 116 + 125 0.05 PCB 118 969 PCB 121 386 PCB 129 0.05 PCB 130 0.05 PCB 131 + 146 0.19 PCB 132 + 153 1.89 PCB 133 0.05 PCB 134 0.05 PCB 137 0.06 PCB 138 + 158 0.72 PCB 139 0.11 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.74 Special study sediment organics results at VADEQ ambient monitoring station 6BPWL001.49 on the North Fork Powell River (01/26/2006) (cont).


(ug/Kg) (ug/Kg) PCB 141 PCB 149 PCB 151 PCB 156 119 PCB 157 0.05 PCB 163 + 164 0.23 PCB 167 0.05 PCB 170 + 190 0.23 PCB 171 0.06 PCB 172 0.05 PCB 174 0.16 PCB 175 0.05 PCB 176 0.05 PCB 177 0.11 PCB 178 0.05 PCB 180 + 193 0.41 PCB 183 74.1 PCB 185 0.05 PCB 187 151 PCB 191 0.05 PCB 194 0.08 PCB 196 + 203 0.10 PCB 199 0.09 PCB 200 0.05 PCB 201 0.05 PCB 202 0.05 PCB 206 79.0 PCB 42 + 59 0.26 PCB 44 195 PCB 52 201 PCB 66 422 PCB 70 0.99 PCB 77 194 PCB 82 0.17 PCB 85 + 110 + 120 5.28 PCB 86 + 97 0.17 PCB 87 + 111 + 115 0.06 PCB 91 0.14 PCB 99 0.38 PCB, TOTAL 676 17.2 1PEC = Probable Effect Concentration (McDonald, 2000), A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).





(ug/Kg) (ug/Kg) Perylene 36.7 Phenanthrene 1,170 596 Pyrene 1,520 327 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).



Table 6.75 Special study sediment organics results at VADEQ ambient monitoring station 6BPWL004.10 on the North Fork Powell River (01/26/2006).

Parameter PEC1 (ug/Kg) VA 99th Percentile2 (ug/Kg) (ug/Kg) 1,4-DIMETHYL NAPTHALENE 141 1-METHYL PHENANTHRENE 0.09 1-Methylnaphthalene 0.43 2,3,5-TRIMETHYL NAPHTHALENE

79.8

2,6-Dimethylnaphthalene 177.5 2-Methylanthracene 47.3 2-Methyl Napthalene 83 326.4 3,6-DIMETHYL PHENANTHRENE

13.7

Acenaphthylene 121 10.6 B2E PHTH 42.8 Benzo[a]anthracene 1,050 63 Benzo[a]pyrene 1,450 32 Benzo[b]fluoranthene 60.2 BIPHENYL 31.7 BTLBNZY LPHTHALAT 42.3 BZO(GHI)PERYLENE 15.8 Chrysene 88.2 DETHPHTH 17.4 Dibenz[a,h]anthracene 318 10 DNB PHTH 78.7 Fluoranthene 2,230 157 Fluorene 536 17 Indeno[1,2,3-cd]pyrene 1,450 20 METHYL FLUORENE 27 Naphthalene 561 232 PCB 101 1,166 PCB 105 354.83 PCB 116 + 125 0.05 PCB 118 1,137 PCB 121 0.17 PCB 129 0.05 PCB 130 0.05 PCB 131 + 146 0.14 PCB 132 + 153 0.93 PCB 133 0.05 PCB 134 0.05 PCB 135 + 144 0.10 PCB 137 0.05 PCB 138 + 158 0.61 PCB 139 0.08 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).




Parameter PEC1 (ug/Kg) (ug/Kg) PCB 141 106.56 PCB 149 0.08 PCB 151 96.26 PCB 156 94.06 PCB 157 0.05 PCB 163 + 164 0.16 PCB 167 0.05 PCB 170 + 190 0.10 PCB 171 0.05 PCB 172 0.05 PCB 174 0.07 PCB 175 0.05 PCB 176 0.05 PCB 177 0.05 PCB 178 0.05 PCB 179 0.05 PCB 180 + 193 0.16 PCB 183 50 PCB 185 0.05 PCB 187 55.13 PCB 191 0.05 PCB 194 0.05 PCB 195 50 PCB 196 + 203 0.05 PCB 199 0.05 PCB 200 0.05 PCB 201 0.05 PCB 202 0.05 PCB 206 50 PCB 42 + 59 0.09 PCB 44 96.96 PCB 52 105.24 PCB 56 + 60 0.10 PCB 66 126.03 PCB 70 0.36 PCB 71 0.05 PCB 82 0.11 PCB 83 0.07 PCB 85 + 110 + 120 4.42 PCB 86 + 97 0.13 PCB 87 + 111 + 115 0.05 PCB 91 0.09 1PEC = Probable Effect Concentration (McDonald, 2000), A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).




Parameter PEC1 (ug/Kg) VA 99th Percentile2 (ug/Kg) (ug/Kg) PCB 99 0.34 PCB, TOTAL 676 12.22 Perylene 10 Phenanthrene 1,170 185.4 Pyrene 1,520 123.1 1PEC = Probable Effect Concentration (McDonald, 2000), 2VA 99th percentile – VADEQ screening value, A blank screening value means none has been specified, Bold values exceed a screening value and all data is in parts per billion ug/Kg dry weight basis (ppb).

Table 6.76 Summary of sediment organic compounds that exceeded screening values at VADEQ North Fork Powell River monitoring stations.

Station Date Parameter Screening Value (ug/Kg) Value (ug/Kg)6BPWL001.49 1/26/2006 Napthalene 561 933 6BPWL001.49 1/26/2006 2-Methyl Napthalene 83 1,067 6BPWL002.48 6/18/2002 2-Methyl Napthalene 83 235 6BPWL004.10 1/26/2006 2-Methyl Napthalene 83 326

6.6.1.7 Dissolved Metals Sampling Results – North Fork Powell River

Dissolved metals were collected at two VADEQ ambient monitoring stations on the

North Fork Powell River and all of the values were below the chronic water quality

standard. The results are shown in Table 6.77. Only data that exceeded the minimum

laboratory detection levels is shown.

Table 6.77 Dissolved metal concentrations at two VADEQ ambient monitoring stations on the North Fork Powell River.

Metal

6BPWL001.49 01/26/06 (ug/L)

Chronic WQS (ug/L)1

6BPWL004.10 08/12/03 (ug/L)

Chronic WQS (ug/L)1

Aluminum 14 NA 20 NA Arsenic 0.2 NA 0.26 NA Barium 18.4 NA 28 NA Chromium (III) 0.8 247.39 Copper 0.3 11.09 0.86 14.24 Manganese 16.9 NA 15.1 NA Nickel 0.9 19.07 1.6 24.44 Zinc 1.9 99.45 1.62 127.47 1WQS = VADEQ water quality standard. WQS are based on formulas dependent on the hardness at the time of sampling, N/A = Not Applicable, there is no chronic water quality standard for this metal and all values in parts per billion ug/Kg dry weight basis (ppb).



6.6.1.8 Sediment Sampling Results – South Fork Powell River

VADEQ performed special study sediment metals sampling at VADEQ ambient

monitoring station 6BPLL006.38 on the South Fork Powell River, Tables 6.78. Only

data that exceeded the minimum laboratory detection levels is shown.

Table 6.78 Special study sediment metal sampling results at VADEQ ambient monitoring station 6BPLL006.38 on the South Fork Powell River.

Metal PEC1 (mg/Kg)08/05/96 (mg/Kg)

05/05/99 (mg/Kg)

Arsenic 33 5 Chromium, Total 111 9 10.9 Copper 149 7 18.4 Iron NA 12,900 12,900 Lead 128 9 9.8 Manganese NA 309 303 Nickel, total 48.6 13 10.6 Zinc 459 48 40.4 1PEC = Probable Effect Concentration (McDonald, 2000), , NA = None specified and all values in parts per million mg/Kg dry weight basis (ppm).

6.7 VADEQ special Upper Powell River PAH monitoring sweep June 2009

On June first through the third 2009 VADEQ performed a monitoring sweep primarily in

the Upper Powell River Basin to try and isolate the geographic areas contributing high

naphthalene concentrations to the Powell River. Ten stations were monitored in the

Upper Powell River (Figure 6.21). This figure shows the sites in the watershed where the

highest concentrations of naphthalene were found. An additional monitoring station was

placed in the lower Powell River Basin near the Virginia/Tennessee state line (Figure

6.22). Table 6.79 shows the eleven monitoring stations and provides a physical

description of their location.

Sediment quality guidelines are an area of continuing research and development. In an

effort to focus agreement among various guidelines, MacDonald et al. (2000) developed

consensus-based threshold effect concentrations (TECs) and probable effect

concentrations (PECs). VADEQ uses PEC values as sediment screening guidelines.

Using correlated sediment toxicity and sediment chemistry data, MacDonald



demonstrated that most TECs provided an accurate basis for predicting the absence of

toxicity, and PECs provided an accurate basis for predicting sediment toxicity.

Therefore, values below TEC levels are not expected to cause toxicity, and values above

PEC levels are expected to cause toxicity. In addition there are several PAH compounds

that don’t have PEC levels but VADEQ has established a 99th percentile screening level

for them. This screening value was treated in the same manner as a PEC screening value.

Table 6.80 shows the PAH sediment concentration data collected in June 2009 sweep.

The data indicates that the largest sediment concentrations of naphthalene are in the

northwest portion of the Upper Powell River. In addition they confirm previously

collected PAH monitoring data in the Powell River Basin that indicated high sediment

naphthalene concentrations in the Powell River.

One method to determine the combined toxicity potential is to calculate a hazard

quotient. A hazard quotient is calculated by dividing the measured result by the PEC or

screening value. Summing the results provides a hazard index and index values greater

than 1.0 can indicate a potentially toxic situation, (Table 6.81), (Ingersoll et. al., 2000).

Every monitoring station except 6BPLL000.27 had a hazard quotient that exceeded 1.0.

Organic compounds such as PAHs preferentially bind to organic matter in sediment.

They are much less likely to bind to sand and other inorganic matter in the sediment

layer. Therefore, when comparing multiple monitoring sites it is important to remember

that higher amounts of organic compounds at one site could be a function of much more

organic matter being available at that site.

Considerable care was taken during the sediment sampling in the Powell River Basin to

get sediment of similar color and consistency at each site. TOC concentrations ranged

from 9.9 to 75.6 g/kg (Table 6.82), however, differences in TOC levels among sites did

not explain differences in PAH concentrations. Sites with PAH hazard indices >1 had

TOC levels as low as 17.7 g/kg and as high as 75.6 g/kg.

Another consideration is particle size. Fine-grained organic sediments have more surface

area and therefore more potential binding sites for organic compounds such as PAHs.



Particle sizes at the 11 monitoring stations were examined and found to be consistent

among all of the monitoring stations (Table 6.83).

Figure 6.21 Upper Powell River VADEQ monitoring stations June 2009.



Figure 6.22 Lower Powell River VADEQ monitoring station June 2009.

Table 6.79 Special study PAH monitoring sweep sampling sites June 1-3, 2009 Station Location Stream Name

6BBLK000.13 Black Creek upstream on confluence with Powell River Black Creek 6BCAL001.57 Callahan Cr. and Nickols Rd Callahan Creek 6BLOC001.05 Looney Cr. and Exeter Rd. Looney Creek 6BPIG000.04 Pigeon Cr. and Exeter Rd. Pigeon Creek 6BPLL000.27 South Fork Powell at Bridge 80, DEQ Station PLL 0.27 South Fork Powell River6BPOW115.51 Powell River and State HW 661 Powell River 6BPOW179.20 DEQ Station POW 179.20 Powell River 6BPOW183.55 Powell River at Kent Junction Powell River 6BPOW193.38 Powell River and Kent Junction Rd upstream of Black Creek Powell River 6BPOW197.21 Powell River and State HW 621 Powell River 6BRIN000.31 Roaring Fork and Dunbar Rd Roaring Fork

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Table 6.80 Special study sediment PAH results at VADEQ ambient monitoring stations in the Powell River Basin June 1-3, 2009.

PAH compound PEC

(mg/Kg)

Wisconsin screening

value (mg/Kg)

TEC (mg/Kg)

6BCAL001.57 6/2/2009 (mg/Kg)

6BPOW115.51 6/3/2009 (mg/Kg)

6BRIN000.31 6/2/2009 (mg/Kg)

6BPOW179.20 6/1/2009 (mg/Kg)

6BPLL000.27 6/2/2009 (mg/Kg)

6BPOW193.38 6/2/2009 (mg/Kg)

Acenaphthene 0.089 0.019 0.016 0.014 0.013 ND 0.022 Acenaphthylene 0.128 0.004 0.000 0.033 ND ND 0.000

Anthracene 0.845 0.057 0.042 0.035 0.019 0.024 0.008 0.110 Benzo[a]anthracene 1.050 0.108 0.140 0.044 0.063 0.140 0.044 0.190

Benzo[a]pyrene 1.450 0.15 0.059 0.022 0.035 0.120 0.043 0.150 Benzo[b]fluoranthen

e 0.086 0.032 0.057 0.130 0.072 0.160

Benzo[g,h,i]perylene 0.028 0.017 0.020 0.038 0.023 0.087 Benzo[k]fluoranthen

e 0.029 0.007 0.016 0.033 0.021 0.150

Chrysene 1.290 0.166 0.210 0.054 0.150 0.220 0.049 0.230 Dibenz[a,h]anthrace

ne 0.135 0.033 0.010 0.005 0.007 0.014 0.008 0.022

Fluoranthene 2.230 0.423 0.320 0.051 0.150 0.310 0.150 0.580 Fluorene 0.536 0.077 0.043 0.051 0.048 0.041 ND 0.032

Indeno[1,2,3-cd]pyrene 0.025 0.009 0.016 0.065 0.035 0.086

Naphthalene 0.561 0.176 1.000 1.100 1.100 1.200 0.140 0.140 Phenanthrene 1.170 0.204 0.840 0.640 0.880 0.780 0.050 0.530

Pyrene 1.520 0.195 0.300 0.063 0.150 0.290 0.075 0.470 2-MetNap 0.201 1.500 1.500 1.600 1.500 0.047 0.290

1,1-Biphenyl 0.160 0.120 0.160 0.140 ND ND 2-Chloronaphthalene ND ND ND ND ND ND

Caprolactam ND ND ND ND ND ND Carbazole 0.038 0.042 0.041 0.046 0.011 0.032

Dibenzofuran 0.420 0.360 0.430 0.390 ND 0.095 Sum 22.8 NA 1.61 5.273 4.169 4.989 5.494 0.775 3.376

All values are in mg/kg, ND – substance not detected, TEC Threshold Effect Concentration (MacDonald et al., 2000), PEC Probable Effect Concentration (MacDonald et al., 2000), Values in italics exceed the TEC value, bold values exceed a toxic screening level, NA Not Available, ND Not Detected

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Table 6.80 Special study sediment PAH results at VADEQ ambient monitoring stations in the Powell River Basin June 1-3, 2009 (cont.).

PAH compound PEC

(mg/Kg)

Wisconsin screening

value (mg/Kg)

TEC (mg/Kg)

6BPOW183.55 6/2/2009 (mg/Kg)

6BPIG000.04 6/2/2009 (mg/Kg)

6BLOC001.05 6/3/2009 (mg/Kg)

6BBLK000.13 6/3/2009 (mg/Kg)

6BPOW197.21 6/3/2009 (mg/Kg)

Acenaphthene 0.089 ND ND 0.036 ND ND Acenaphthylene 0.128 ND ND 0.010 ND ND

Anthracene 0.845 0.057 0.018 0.022 0.069 ND 0.005 Benzo[a]anthracene 1.050 0.108 0.054 0.065 0.420 0.011 0.026

Benzo[a]pyrene 1.450 0.15 0.035 0.040 0.390 0.006 0.012 Benzo[b]fluoranthene 0.057 0.064 0.430 0.011 0.022 Benzo[g,h,i]perylene 0.024 0.026 0.270 0.008 0.009 Benzo[k]fluoranthene 0.015 0.018 0.430 ND 0.007

Chrysene 1.290 0.166 0.069 0.100 0.630 0.024 0.045 Dibenz[a,h]anthracene 0.135 0.033 0.007 0.008 0.120 ND ND

Fluoranthene 2.230 0.423 0.130 0.110 1.500 0.014 0.030 Fluorene 0.536 0.077 0.037 0.028 0.059 0.015 0.011

Indeno[1,2,3-cd]pyrene 0.020 0.019 0.250 0.009 0.006 Naphthalene 0.561 0.176 0.620 0.720 0.720 0.200 0.088 Phenanthrene 1.170 0.204 0.450 0.510 1.300 0.180 0.250

Pyrene 1.520 0.195 0.120 0.130 1.200 0.018 0.034 2-MetNap 0.201 0.840 1.100 1.200 0.330 0.190

1,1-Biphenyl 0.077 0.092 0.110 ND ND 2-Chloronaphthalene ND ND ND ND ND

Caprolactam ND ND ND ND ND Carbazole 0.031 0.031 0.110 ND 0.008

Dibenzofuran 0.210 0.290 0.410 0.082 0.080 Sum 22.8 NA 1.61 2.814 3.373 9.664 0.908 0.822

All values are in mg/kg, ND – substance not detected, TEC Threshold Effect Concentration (MacDonald et al., 2000), PEC Probable Effect Concentration (MacDonald et al., 2000), Values in italics exceed the TEC value, bold values exceed a toxic screening level, NA Not Available, ND Not Detected

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Table 6.81 Sediment PAHs hazard quotient* in sweep of Powell River watershed, June 1-3, 2009.

PAH Compound PEC

(mg/Kg)

Wisconsin screening

value (mg/Kg)

6BCAL001.57 6/2/2009 (mg/Kg)

6BPOW115.51 6/3/2009 (mg/Kg)

6BRIN000.31 6/2/2009 (mg/Kg)

6BPOW179.20 6/1/2009 (mg/Kg)

6BPLL000.27 6/2/2009 (mg/Kg)

6BPOW193.38 6/2/2009 (mg/Kg)

2-MetNap 0.201 7.463 7.463 7.960 7.463 0.234 1.443 Acenaphthene 0.089 0.213 0.180 0.157 0.146 0.000 0.247

Acenaphthylene 0.128 0.034 0.000 0.258 0.000 0.000 0.000 Anthracene 0.845 0.050 0.041 0.022 0.028 0.009 0.130

Benzo[a]anthracene 1.05 0.133 0.042 0.060 0.133 0.042 0.181 Benzo[a]pyrene 1.45 0.041 0.015 0.024 0.083 0.030 0.103

Chrysene 1.29 0.163 0.042 0.116 0.171 0.038 0.178 Dibenz[a,h]anthracene 0.135 0.074 0.036 0.054 0.104 0.056 0.163

Fluoranthene 2.23 0.143 0.023 0.067 0.139 0.067 0.260 Fluorene 0.536 0.080 0.095 0.090 0.076 0.000 0.060

Naphthalene 0.561 1.783 1.961 1.961 2.139 0.250 0.250 Phenanthrene 1.17 0.718 0.547 0.752 0.667 0.043 0.453

Pyrene 1.52 0.197 0.041 0.099 0.191 0.049 0.309 Hazard Index (sum of Hazard

Quotients)** 11.09 10.49 11.62 11.34 0.82 3.78

*Hazard Quotients were calculated as the ratio of measured concentration to the PEC or state screening value for that compound. **Hazard Index was calculated as the sum of all hazard quotients for individual PAH compounds. Hazard Quotients or Hazard Indices that exceed 1.0 indicate that toxic effects on benthos are possible. Hazard ratios were not calculated for estimated values, A bold hazard index exceeds 1.0, PAH compounds exhibit similar exposure pathways and modes of action so are assumed to be additive in effect.

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Table 6.81 Sediment PAHs hazard quotient* in sweep of Powell River watershed, June 1-3, 2009 (cont.).

PAH Compound PEC

(mg/Kg)

Wisconsin screening

value (mg/Kg)

6BPOW183.55 6/2/2009 (mg/Kg)

6BPIG000.04 6/2/2009 (mg/Kg)

6BLOC001.05 6/3/2009 (mg/Kg)

6BBLK000.13 6/3/2009 (mg/Kg)

6BPOW197.21 6/3/2009 (mg/Kg)

2-MetNap 0.201 4.179 5.473 5.970 1.642 0.945 Acenaphthene 0.089 0.000 0.000 0.404 0.000 0.000

Acenaphthylene 0.128 0.000 0.000 0.078 0.000 0.000 Anthracene 0.845 0.021 0.026 0.082 0.000 0.006

Benzo[a]anthracene 1.05 0.051 0.062 0.400 0.010 0.025 Benzo[a]pyrene 1.45 0.024 0.028 0.269 0.004 0.008

Chrysene 1.29 0.053 0.078 0.488 0.019 0.035 Dibenz[a,h]anthracene 0.135 0.050 0.059 0.889 0.000 0.000

Fluoranthene 2.23 0.058 0.049 0.673 0.006 0.013 Fluorene 0.536 0.069 0.052 0.110 0.028 0.021

Naphthalene 0.561 1.105 1.283 1.283 0.357 0.157 Phenanthrene 1.17 0.385 0.436 1.111 0.154 0.214

Pyrene 1.52 0.079 0.086 0.789 0.012 0.022

Hazard Index (sum of Hazard Quotients) 6.08 7.63 12.55 2.23 1.45

*Hazard Quotients were calculated as the ratio of measured concentration to the PEC or state screening value for that compound. **Hazard Index was calculated as the sum of all hazard quotients for individual PAH compounds. Hazard Quotients or Hazard Indices that exceed 1.0 indicate that toxic effects on benthos are possible. Hazard ratios were not calculated for estimated values, A bold hazard index exceeds 1.0, PAH compounds exhibit similar exposure pathways and modes of action so are assumed to be additive in effect



Table 6.82 Sediment total organic carbon and particle size in sweep of Powell River watershed, June 1-3, 2009.

Station %Sand %Clay %Silt TOC, g/Kg 6BBLK000.13 78.52 9.59 11.89 21.4 6BCAL001.57 86.53 6.71 6.76 62.7 6BLOC001.05 76.88 11.85 11.26 75.6 6BPIG000.04 81 8.53 10.47 55.8 6BPLL000.27 75.33 11.68 13 9.92 6BPOW115.51 89.88 6.14 3.98 55.7 6BPOW179.20 75.14 12.42 12.45 51.2 6BPOW183.55 79.01 10.47 10.52 27.4 6BPOW193.38 89.72 4.95 5.33 17.7 6BPOW197.21 72.9 11.54 15.56 59.4 6BRIN000.31 88.21 6.73 5.06 74.5 TOC total organic carbon. VADEQ also collected sediment metals and conventional water column parameters

during the three day sweep. Sediment metal concentrations were all below their

respective PEC values and the conventional water column parameters were within

expected ranges (Appendix B-Special Sampling).

6.8 Endangered and threatened mussels in the Powell River Basin

The Clinch and Powell rivers originate in the mountainous terrain of southwestern

Virginia and extend into northeastern Tennessee, flowing into the upper reaches of the

Tennessee River. The free-flowing portions of the Clinch and Powell Valley watersheds

have historically had one of the richest assemblages of native fish and freshwater mussels

in the world. Nearly half of the species historically present are now extinct, threatened, or

endangered. Currently, the Clinch and Powell river basin supports more threatened and

endangered aquatic species than almost any other basin in North America. The degree of

loss is unprecedented among other wide-ranging faunal groups in North America.

Therefore, the Clinch and Powell watersheds fauna has national significance. The fact

that mussels are sedentary and benthic makes them even more of a target for water

pollutant exposure. The siphoning mode of feeding used by mussels also makes them

susceptible to bioaccumulative effects of organic pollutants. There has been significant

federal and state cooperation in developing plans and courses of action to reduce these

trends. Despite the implementation of recovery plans for most of the federally protected



species in these basins it appears that these species are either declining or becoming

extinct at an alarming rate due to impacts from mining, agriculture, urbanization, and

other stressors (USEPA, 2002). For example, at monitored sites in the Powell River in

Tennessee and Virginia, mussel populations have declined by 63%. In a remote and very

scenic section of the river along the Virginia-Tennessee border, mussel diversity (>30

species) remains high, but annual rate of recruitment is low and unlikely to sustain viable

populations for some species. Mussels are now rare to absent in the upper 25 miles of the

Powell River from Woodway upstream to Appalachia, VA. Table 6.83 shows a list of 21

Federally and State endangered and threatened mussel species in the Powell River Basin

out of a total of approximately 43 species (VA Natural Heritage Resources Information

accessed 10/13/2008).

Table 6.83 Endangered and threatened mussels in the Powell River Basin.

Common Name Federal Status

State Status

Appalachian Monkeface LE LE Birdwing Pearlymussel LE LE Black Sandshell LT Cracking Pearlymussel LE LE Cumberland Combshell LE LE Cumberland Monkeyface LE LE Deertoe LE Dromedary Pearlymussel LE LE Elephant Ear LE Fine-rayed Pigtoe LE LE Fragile Papershell LT Little-winged Pearlymussel LE LE Oyster Mussel LE LE Pimple Back LT Purple Bean LE LE Rough Rabbits Foot LE LE Sheepnose C LT Shiny Pigtoe LE LE Slabside Pearlymussel C LT Snuffbox LE Tennessee Heelsplitter LE LE – Listed endangered, LT – Listed threatened, C – Candidate for listing



Significant projects aimed at the reducing the impacts from acid mine drainage have been

completed in the Powell River watershed. In 2003 the USACOE completed a $1.8

million dollar reclamation project in the Ely Creek watershed to reduce the impact of acid

mine drainage (AMD) from abandoned coal mining sites, Figure 6.23. Acid mine

drainage is reclaimed in a two stage process, first water is directed through a Successive

Alkalinity Producing Systems (SAPS) treatment cell that neutralizes the water and then

raises the pH with addition of limestone. The water is then directed to a constructed

wetland area where the metals precipitate out. The reclamation process was successful in

raising the pH and decreasing iron, aluminum and conductivity (USACOE, 2004).

Figures 6.24, 6.25 and 6.26 show improvements in an acid mine drainage seep to Bean

Creek. It is important to note that after 10 to 15 years these systems require significant

maintenance to assure proper treatment of the AMD affected water.

Figure 6.23 Ely Creek restoration site, photo by the USACOE.



26.43

116.72

1.53 0.570.00

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40.00

60.00

80.00

100.00

120.00

Iron Aluminum

Ave

rage

Con

cent

ratio

ns (m

g/L)

1996-2003 2005-2006

Figure 6.24 Average total iron and total aluminum concentrations before and after reclamation

7.08

2.73

0.00

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Fie

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H (s

td u

nits

)

Figure 6.25 Average field pH measurements before and after reclamation



869

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( 0m

hos/

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Figure 6.26 Average conductivity measurements before and after reclamation

In early 2008 phase II of a restoration project in the Lick Creek watershed was

completed, Figure 6.27. This project was a passive system similar to the one described in

Ely Creek above. Early results indicate improvement in the pH and reductions in iron

and aluminum, but full treatment was not being achieved as of March 2008 (AML

advisory committee, 2008).



Figure 6.27 Lick Branch restoration site in 2007, photo by USACOE.


TMDL ENDPOINT-POWELL RIVER 7-1

7. TMDL ENDPOINT: STRESSOR IDENTIFICATION – POWELL RIVER

7.1 Stressor Identification – Powell River

The Powell River begins in northwestern Wise County Virgnia near the

Virgnia/Kentucky state line, and travels in a southwesterly direction for approximately 80

miles through Wise and Lee Counties before reaching the Virginia/Tennessee state line.

There are three impaired benthic segments on the mainstem of the Powell River on

Virginia’s 303(d) list. The first segment begins at the Powell River’s confluence with

Roaring Branch and continues downstream to Dakota Street in Big Stone Gap for a total

of 2.62 stream miles (VADEQ segment number VAS-P17R_POW01A94). In this

segment VADEQ benthic monitoring station 6BPOW180.72 indicated impairment. The

second segment begins at the Powell River’s confluence with Poor Valley Creek and

continues downstream to the upper end of a public water supply section for a total of 6.38

stream miles (VADEQ segment identification number VAS-P19R_POW03A00).

VADEQ benthic monitoring station 6BPOW166.92 indicated impairment in this

segment. In the third segment VADEQ benthic monitoring station 6BPOW120.12

indicated impairment from the Powell River’s confluence with Hardy Creek downstream

to its confluence with Yellow Creek for a distance of 8.42 stream miles (VADEQ

segment identification number VAS-P23R_POW02A00).

For a water quality constituent without an established standard, criteria, or screening

value, a 90th percentile-screening value was used. The 90th percentile screening values

were calculated from 49 VADEQ monitoring stations in southwest Virginia on third and

fourth order streams that were used as benthic reference stations or were otherwise non-

impaired based on the most recent benthic sampling results. The 90th percentile

screening values were used to develop a list of possible stressors to the benthic

community in the Powell River. For a parameter to become a probable stressor,

additional supporting information was required (e.g., benthic habitat, metrics, and

scientific references documenting potential adverse effects for aquatic life). Graphs are

shown for parameters that exceeded the screening value in more than 10% of the samples

collected within the impaired segment or if the parameter had extreme values. Graphs for


7-2 TMDL ENDPOINT-POWELL RIVER

parameters with more than one but less than nine data points are not shown in this section

unless there are extreme values. The presence of nine values was selected as a cutoff in

order to avoid using limited data from stations that were not sampled during different

seasons of the year or different flow regimes in the Powell River. However, all data were

reviewed to ensure consistency with typical value ranges for a parameter in streams in

Virginia.

TMDLs must be developed for a specific pollutant(s). Benthic assessments are very good

at determining if a particular stream segment is impaired or not, but they usually do not

provide enough information to determine the cause(s) of the impairment when organisms

are not classified beyond the family level. The process outlined in the Stressor

Identification Guidance Document (EPA, 2000) was used to separately identify the most

probable stressor(s) for the Powell River. A list of candidate causes was developed from

published literature and VADEQ staff input. Chemical and physical monitoring data

provided evidence to support or eliminate potential stressors. Individual metrics for the

biological and habitat evaluation were used to determine if there were links to a specific

stressor(s). Land use data, as well as a visual assessment of conditions along the stream,

provided additional information to eliminate or support candidate stressors. The potential

stressors are: sediment, toxics, low dissolved oxygen, nutrients, pH, metals,

conductivity/total dissolved solids, temperature, and organic matter.

The results of the stressor analysis for the Powell River are divided into three categories:

Non-Stressor(s): Those stressors with data indicating normal conditions, without water quality standard violations, or without the observable impacts usually associated with a specific stressor, were eliminated as possible stressors. Non-stressors are listed in Table 7.1.

Possible Stressor(s): Those stressors with data indicating possible links, but inconclusive data, were considered to be possible stressors. Possible stressors are listed in Table 7.2.

Most Probable Stressor(s): The stressor(s) with the most consistent information linking it with the poorer benthic and habitat metrics was considered to be the most probable stressor(s). Probable stressors are listed in Table 7.3.



7.2 Non-Stressors

Non- stressors in the Powell River are reported in Table 7.1.

Table 7.1 Non-Stressors in the Powell River. Parameter Location in Document

Low dissolved oxygen section 7.2.1 Nutrients section 7.2.2 Toxics (ammonia, PCBs and pesticides except Heptachlor epoxide) section 7.2.3 Metals section 7.2.4 Temperature section 7.2.5 Field pH section 7.2.6

There is always a possibility that conditions in the watershed, available data, and the

understanding of the natural processes change more than anticipated by the TMDL. If

additional monitoring shows that different most probable stressor(s) exist or water quality

target(s) are protective of water quality standards (WQS), then the Commonwealth will

make use of the option to refine the TMDLs for re-submittal to EPA for approval.

7.2.1 Low Dissolved Oxygen

Dissolved oxygen (DO) concentrations were well above the VADEQ minimum WQS of

4.0 mg/L at all three VADEQ ambient monitoring stations in the vicinity of the impaired

VADEQ benthic monitoring stations (6BPOW138.91, 6BPOW165.78 and

6BPOW179.20 (Figures 7.1, 7.2 and 7.3). Since 1990, dissolved oxygen has been

measured occasionally at eight other sites on the Powell River by VADEQ, and no values

were ever below the minimum WQS. Low dissolved oxygen is considered a non-

stressor.



0.0

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Figure 7.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPOW138.91.

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7.2.2 Nutrients

Total phosphorus (TP) concentrations were very low at all three VADEQ ambient

monitoring stations in the vicinity of the impaired VADEQ benthic monitoring stations.

Only one value out of 420 samples exceeded the VADEQ screening value of 0.2 mg/L,

Figures 7.4, 7.5 and 7.6. Nitrate nitrogen concentrations were also low, with 97% of the

values at all three monitoring stations below 1.23 mg/L (Figures 7.7, 7.8 and 7.9).

Nutrients are considered non-stressors.



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al p

hosp

horu

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) .

VADEQ screening value = 0.2 mg/L

Figure 7.4 Total phosphorus concentrations at VADEQ station 6BPOW138.91.

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al p

hosp

horu

s (m

g/L

) .



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Tot

al n

itrat

e ni

trog

en (m

g/L

) .

90th percentile screening value = 1.23 mg/L

Figure 7.7 Nitrate-nitrogen concentrations at VADEQ station 6BPOW138.91.



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7.2.3 Toxics (ammonia, PCBs and pesticides)

Ninety-five percent of the ammonia (NH3/NH4) samples collected in the Powell River

were below the minimum laboratory level of detection (0.04 mg/L). The remaining

values were well below the chronic VADEQ WQS. Both the chronic and acute ammonia

WQSs are dependent on the pH and temperature at the time of sampling. Only six

ammonia (NH3/NH4) samples collected at VADEQ station 6BPOW138.91 were above

the minimum laboratory detection level. Graphs for the two remaining VADEQ ambient

monitoring stations are shown in Figures 7.10 and 7.11. Ammonia is considered a non-

stressor in the Powell River. Sediment pesticide and PCB values were below established

screening levels (Tables 6.56, 6.63 and 6.64) and are also considered non-stressors, with

the exception of Heptachlor epoxide, which will be discussed in section 7.3.1.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

5/18

/92

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/93

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11/1

8/02

Rat

io o

f Obs

erve

d Va

lues

to th

e C

hron

ic W

QS

Exceeds Chronic Water Quality Standard

Figure 7.10 Ammonia-nitrogen concentrations at VADEQ station 6BPOW165.78.



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

4/3/

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Rat

io o

f Obs

erve

d Va

lues

to th

e C

hron

ic W

QS

Exceeds Chronic Water Quality Standard

Figure 7.11 Ammonia-nitrogen concentrations at VADEQ station 6BPOW179.20.

7.2.4 Metals

This section discusses VADEQ water quality monitoring for metals dissolved in the

water column and metals in the sediment. All sediment metal values were below the PEC

values (Tables 6.54 and 6.57 through 6.62).

Water column dissolved metals were sampled at eight VADEQ monitoring stations on

the Powell River and all results were below the appropriate WQS (Tables 6.66 through

6.69). Not all of the metals listed have established VADEQ or USEPA WQSs.

Based on the results of the dissolved metals and sediment metals data, metals are

considered non-stressors.

7.2.5 Temperature

The maximum temperature standard for the Powell River is 31.0°C. The maximum

temperature recorded at the three VADEQ ambient monitoring stations on the Powell



River was 27.2°C (Figures 7.12, 7.13 and 7.14). Temperature measurements have been

occasionally recorded at eight other VADEQ monitoring sites on the Powell River and all

values were below the maximum WQS. Temperature is considered a non-stressor in the

Powell River.

0

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Tem

pera

ture

(0 C)

.

DEQ standard = 310C

Figure 7.12 Temperature measurements at VADEQ station 6BPOW138.91.



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(0 C)

.

DEQ standard = 310C




7.2.6 Field pH

Field pH values were within the minimum (6.0 std units) and maximum (9.0 std units)

VADEQ WQSs at all three VADEQ monitoring stations on the Powell River (Figures

7.15, 7.16 and 7.17). In addition occasional field pH measurements at eight other

VADEQ monitoring sties on the Powell River were within the maximum and minimum

WQSs. Therefore, field pH is considered a non-stressor in the Powell River.

4.0

5.0

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7.0

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Fiel

d pH

(std

uni

ts)

.

VADEQ minimum water quality standard = 6.0 (std units)

VADEQ maximum water quality standard = 9.0 (std units)

Figure 7.15 Field pH measurements at VADEQ station 6BPOW138.91.



4.0

5.0

6.0

7.0

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7

Fiel

d pH

(std

uni

ts)

.



Figure 7.16 Field pH measurements at VADEQ station 6BPOW165.78

4.0

5.0

6.0

7.0

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Fiel

d pH

(std

uni

ts)

.



Figure 7.17 Field pH measurements at VADEQ station 6BPOW179.20.



7.3 Possible Stressors

Possible stressors in the Powell River are reported in Table 7.2.

Table 7.2 Possible Stressors in the Powell River. Parameter Location in Document

Pesticides (Heptachlor epoxide). section 7.3.1 Sulfate section 7.3.2 Organic matter (total organic solids, total organic carbon and total kjeldahl nitrogen) section 7.3.3

Conductivity/total dissolved solids (TDS) section 7.3.4 Toxics (PAHs) Section 7.3.5

7.3.1 Pesticides (Heptachlor epoxide)

Heptachlor epoxide sediment samples exceeded the PEC value of 16 ug/Kg at VADEQ

monitoring stations 6BPOW165.78 (55 ug/Kg) and 6BPOW179.20 (50 ug/Kg) in June

1994. Heptachlor epoxide was the active ingredient in products used to kill termites but

was banned from use in the late 1980s. In recent samples collected on the Powell River,

Heptachlor epoxide has been below the minimum laboratory detection level. Heptachlor

epoxide is considered a possible stressor.

7.3.2 Sulfate

Sulfate concentrations exceeded the 90th percentile screening value (76 mg/L) in more

than 10% of the samples collected at all three VADEQ ambient monitoring stations

evaluated on the Powell River (Figures 7.18, 7.19 and 7.20). The USEPA used sulfate

concentrations as an indicator of impaired macroinvertebrate communities in mid-

Atlantic highland streams (Klemm et al., 2001). Other studies note that sulfate is a

reliable indicator of mining activity and is often linked to depressed benthic health; but,

by itself, has not been shown to actually cause a reduction in the health of benthic

communities (Merricks, 2003). Sulfate is, however, a principle component of total

dissolved solids, which have been shown to impair benthic macroinvertebrate

communities. There is a public water supply WQS of 250 mg/L; but this is for taste and



odor control and does not apply to aquatic life. Therefore, sulfate is considered a

possible stressor.

0

20

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60

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100

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140

16001

/90

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03/0

5

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6

Sulfa

te (m

g/L

) .

90th percentile screening value = 76 mg/L

Figure 7.18 Sulfate concentrations at VADEQ monitoring station 6BPOW138.91.



0

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) .



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Sulfa

te (m

g/L

) .





7.3.3 Organic matter (Total organic solids, total organic carbon and total kjeldahl

nitrogen)

Total organic solids (also called total volatile solids, TVS) provide an indication of

dissolved and suspended organic matter. TVS concentrations exceeded the 90th

percentile screening concentration (63 mg/L) in 11%, 17% and 35% of the samples

collected at VADEQ ambient monitoring stations 6BPOW138.91, 6BPOW165.78 and

6BPOW179.20 respectively (Figures 7.21, 7.22 and 7.23). Chemical oxygen demand

(COD) is another parameter that can provide an indication of high organic matter in a

stream. COD concentrations were below 10% at all three of the ambient monitoring

stations in the impaired sections of the Powell River. Total organic carbon (TOC)

concentrations exceeded the 90th percentile screening value (4.0 mg/L) at VADEQ

ambient monitoring station 6BPOW138.91 in three out of 17 samples (Figure 7.24). Less

than 10 percent of the Total kjeldahl nitrogen (TKN) concentrations exceeded the 90th

percentile screening value of 0.4 mg/L.

0

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Tot

al o

rgan

ic so

lids (

mg/

L)

.


Figure 7.21 Total organic solids concentrations at VADEQ monitoring station 6BPOW138.91.



0

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Tot

al o

rgan

ic c

arbo

n (m

g/L

) .


Figure 7.24 Total organic carbon concentrations at VADEQ monitoring station 6BPOW138.91.

The assemblage for all of the benthic stations on the Powell River from the VADEQ

Ecological Data Application System (EDAS) database were examined, and

Hydropsychidae (netspinning caddisflies) were found to be the most dominant or a very

significant family at most of the VADEQ benthic monitoring stations (7% - 37%).

According to Voshell (2002), “If common netspinners account for the majority of the

community that is a reliable indicator of organic or nutrient pollution.” Also Naididae

(an aquatic worm) was fairly significant at two of the VADEQ benthic monitoring

stations. This type of organism is also often associated with polluted and degraded water

quality. For the purposes of this stressor analysis, organic matter is considered a possible

stressor because, as part of this overall TMDL study, an E. coli TMDL is also going to be

developed for the Powell River watershed, which will require significant reductions to

the sources of organic matter in the watershed.



7.3.4 Conductivity/Total dissolved solids (TDS)

Conductivity is a measure of the electrical potential in the water based on the ionic

charges of the dissolved compounds that are present. TDS is a measure of the actual

concentration of the dissolved ions, dissolved metals, minerals, and dissolved organic

matter in water. Dissolved ions can include sulfate, calcium carbonate, chloride, etc.

Therefore, even though they are two different measurements, there is a direct correlation

between conductivity and TDS. In the Powell River data set, there was a Pearson

Product Moment Correlation of 0.977 between conductivity and TDS.

High conductivity values have been linked to poor benthic health (Merricks, 2003), and

elevated conductivity is common with land disturbance and mine drainages. A recent

report on the effects of surface mining on headwater stream biotic integrity in Eastern

Kentucky noted that one of the most significant stressors in these watersheds was

elevated TDS (Pond, 2004). Elevated TDS concentrations impact pollution sensitive

mayflies the most. Figure 7.25 from this report shows that “drastic reductions in mayflies

occurred at sites with conductivities generally above 500 μmhos/cm” (Pond, 2004).

Figure 7.25 The relationship between %Ephemeroptera and conductivity from reference and mined sites (Pond, 2004).



Pond speculated that the increased salinity may irritate the gill structures on mayflies and

inhibit the absorption of oxygen, but research has not confirmed this. A typical reference

station in this part of the state can be expected to have at least 50% mayflies out of the

total assemblage. The results of a VADEQ benthic surveys in the Powell River at four

monitoring stations indicated that sensitive mayflies made up between 2% - 5% of the

total benthic assemblage. The members of the more pollution tolerant families

(Caenidae, Baetidae, and Isonychiidae) were not included in this calculation. In the

development of both the Virginia and West Virginia Stream Condition Indices, the

reference streams used had conductivity levels that did not exceed 500 μmhos/cm. In the

absence of a Virginia WQS, the 90th percentile screening value of 402 μmhos/cm was

used. Conductivity values at all three VADEQ stations consistently exceeded the 90th

percentile screening value (402 μmhos/cm) in 61%, 61% and 84% at VADEQ monitoring

stations 6BPOW138.91, 6BPOW165.78 and 6BPOW179.20, Figures 7.26, 7.27 and 7.28.

0

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Con

duct

ivity

(μm

hos/

cm)

.

90th percentile screening value = 402 ⎯mhos/cm

Figure 7.26 Conductivity measurements at VADEQ station 6BPOW138.91.



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ivity

(μm

hos/

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.



The TDS 90th percentile screening value was 260 mg/L. TDS concentrations consistently

exceeded this value in 53%, 57% and 83% of the samples at all three VADEQ monitoring

stations 6BPOW138.91, 6BPOW165.78 and 6BPOW179.20 respectively (Figures 7.29,

7.30 and 7.31).



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al d

isso

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s (m

g/L

) .


Figure 7.29 TDS concentrations at VADEQ station 6BPOW138.91.

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Tot

al d

isso

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solid

s (m

g/L

) .


Figure 7.30 TDS concentrations at 6BPOW165.78.



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Tot

al d

isso

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solid

s (m

g/L

) .


Figure 7.31 TDS concentrations at 6BPOW179.20.

TDS concentrations can be harmful to aquatic organisms without causing death. Aquatic

organisms balance water and internal ions through a number of different mechanisms.

Therefore, high concentrations and significant changes in TDS over long periods of time

can place a lot of stress on the organisms. The resulting chronic stress affects processes

such as growth and reproduction. Sudden large spikes in TDS concentration can be fatal.

A study of TDS toxicity in a coal-mining watershed in southeastern Ohio found the

lowest observed effect concentration (LOEC) on the test organism Isonychia bicolor (a

species of Mayfly) was 1,066 mg/L (Kennedy, 2002). The author carefully noted that

this concentration was specific to the watershed studied, but noted that similar studies

with the same test organism and TDS with varying ionic compositions were toxic

between 1,018 and 1,783 mg/L (Kennedy, 2002). Kennedy also cited a study that

suggested that aquatic organisms should be able to tolerate TDS concentrations up to

1,000 mg/L; however, the test organism used was Chironomous tentans, which is

considerably more pollution tolerant than Isonychia bicolor (Kennedy, 2002). Research

also indicates that the likely mechanism(s) of TDS benthic macroinvertebrate mortality is

from gill and internal tissue dehydration, salt accumulation and compromised



osmoregulatory function. In fact, the rate of change in TDS concentrations may be more

toxic to benthic macroinvertebrates than the TDS alone (Kennedy, 2002).

It is clear from the data available that conductivity and TDS values are high. The Powell

River is considered by the VADEQ to be a fifth order stream at the impaired VADEQ

benthic monitoring stations. Larger streams tend to be comprised of benthic organisms

that are a little more facultative than lower order high gradient streams in the Central

Appalachians. These organisms are generally somewhat more tolerant of higher TDS

concentrations. In addition, TDS TMDLs have been developed for Straight and Callahan

Creeks within the Powell River drainage system. Straight Creek and Callahan Creek

contain most of the mining lands within the Powell River watershed, and are the source

of most of the TDS in the watershed. Implementation of the previously conducted

TMDLs will result in decreasing TDS concentrations in the Powell River. Conductivity

and TDS are considered possible stressors in the Powell River.

7.3.5 Total PAHs (Polycyclic Aromatic Hydrocarbons)

PAHs are a group of chemicals that occur naturally in coal, crude oil, and gasoline.

There are more than 100 different PAHs. PAHs generally occur as complex mixtures,

not as single compounds. PAHs are also present in products made from fossil fuels, such

as coal-tar pitch, creosote, and asphalt. When coal is converted to natural gas, PAHs can

be released. Therefore, some coal-gasification sites may have elevated levels of PAHs.

PAHs also can be released into the air during the incomplete burning of coal, oil, gas, or

any organic substance. When the burning process is less efficient, more PAHs are given

off. Forest fires and volcanoes can produce PAHs naturally. Once released into the

aquatic environment, degradation by micro-organisms is often slow, leading to their

accumulation in exposed sediments, soils, aquatic and terrestrial plants, fish, and

invertebrates. In terms of human health, prolonged exposure to PAHs can have negative

effects on individuals exposed to mixtures of PAHs. Many useful products such as

mothballs, blacktop, and creosote wood preservatives contain PAHs. They are also found

at low concentrations in some special-purpose skin creams and anti-dandruff shampoos

that contain coal tars.



The 16 PAHs that are listed below are the most commonly sampled, for the following

reasons: there is more information available on these PAHs; they are suspected to be

more harmful than some of the other PAHs; they exhibit harmful effects that are

representative of the PAHs; there is a greater chance of exposure to these PAHs than to

the others and in relation to all of the PAHs analyzed (Agency For Toxic Substances and

Disease Registry, August 1995). Sixteen PAHs are currently identified on the USEPA

National Priority List (NPL) hazardous waste list. The list is as follows:

Acenaphthene benzo[b]fluoranthene Fluoranthene Acenaphthylene benzo[g,h,i]perylene Fluorene Anthracene benzo[j]fluoranthene Indeno[1,2,3-c,d]pyrene benz[a]anthracene benzo[k]fluoranthene Phenanthrene Benzo[a]pyrene chrysene Pyrene dibenz[a,h]anthracene

High concentrations of PAHs were found in a sediment samples taken by the VADEQ at

several sites and at different times on the Powell River (Table 6.55). The PAHs that

consistently exceed screening levels used by Virginia are 2-methyl naphthalene and

naphthalene. The exact source or sources of these compounds is not known at the present

time. Most of the naphthalene that enter the environment is from the burning of wood

and fossil fuels. Naphthalene is typically a white solid substance that evaporates easily.

It is used in mothballs, moth flakes and tar camphor. Both coal and petroleum naturally

contain naphthelene. The primary commercial use of naphthelene is the making of

polyvinyl chloride plastics. Naphthalene is also used in making dyes, resins, leather

tanning products and carbaryl (an insecticide known commercially as sevin). Because

naphthalene is so volatile it is usually gone from rivers or lakes within two weeks. In

addition, it binds very weakly to soil and sediments, (Agency For Toxic Substances and

Disease Registry, August 2005).

MapTech reviewed sediment PAH data collected through VADEQ’s Fish Tissue and

Sediment Program from 1995 – 2006 for the state of Virginia. The Virginia Institute of

Marine Science (VIMS) analyzes this data for the VADEQ. In this dataset only six out of

500 naphthalene samples exceeded the Probable Effect Concentration (PEC) that

VADEQ uses as a screening value (561 ug/Kg). None of the six values were in the coal



fields region of southwestern Virginia (the naphthalene values in the Powell River that

did exceed the PEC screening value were collected by VADEQ regional monitoring staff

as part of special studies not related to the statewide Fish Tissue and Sediment Program).

However, 23 naphthalene concentrations exceeded the 95th percentile concentration for

the dataset (130 ug/Kg) and 35% (8) of these samples were in the coalfields region

(Figure 7.32).

Virginia DEQ Naphthalene Sediment Monitoring (1995 - 2006) From the VIMS Laboratory

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Note: Red symbols exceed the 95th percentile

90 0 90 180 Miles

S

N

EW

Naphthalene (ug/kg)# 0 - 52# 52 - 130# 131 - 364# 364 - 975# 975 - 2,216

Virginia Counties and Cities

Figure 7.32 Naphthalene concentrations in bottom sediment in Virginia.

Studies on PAH concentrations in bottom sediment in coal mining areas of the United

States are very limited. In 2002, the US Geological Survey published a report on PAHs

in bottom sediment in the Kanawha River Basin in West Virginia. The investigation

focused on 12 PAHs with criteria (Probable Effect Levels) established by the Canadian

Council of Ministers of the Environment. Six of the twelve PAH compounds (including



naphthalene) had concentrations that exceeded the Probable Effect Level (PEL)

concentration. More importantly the USGS found a significant relationship between the

sum of all the PAHs measured and coal mined watersheds where coal production

exceeded 20 tons per square mile (Messinger, 2002).

PAH concentrations in sediment are typically derived from three sources: naturally

occurring in fossil fuels (petrogenic), those that result from the burning of organic matter

or combustion (pyrogenic), and the transformation of precursors in the environment by

rapid biological/chemical processes (biogenic PAH). PAHs resulting from the biogenic

processes usually do not contribute nearly as much to the total mass of PAH in the

sediment as the inputs from anthropogenic sources. It is sometimes possible to look at

the ratios of various PAH compounds in the sediment to distinguish between petrogenic

and pyrogenic sources (Neff et al., 2005). One technique is to look at the ratio of

phenanthrene and anthracene (PH/AN). Pyrogenic sources typically have ratios less than

5, while petrogenic sources are usually greater than 5. Similarly, the ratio of fluoranthene

to pyrene (FL/PY) is usually just below or greater than one (1) if the source is pyrogenic

but, if it is substantially less than one, then the source is usually petrogenic (Neff et al.,

2005). Table 7.3 provides examples of these two ratios from various sources and the

average from the sampling events by VADEQ in the Powell River sediments. The ratios

for the Powell River sediments are inconsistent falling into both categories. Similar

attempts by the USGS to determine the source(s) of the PAHs in the Kanawha River

Basin report were also inconsistent (Messinger, 2002).



Table 7.3 Ratios of PAH isomers from various sources and the Powell River watershed sediments

Source PH/AN Ratio FL/PY Ratio PYROGENIC SOURCES1

Auto exhaust soot 1.79 0.9 Highway dust 4.7 1.4 Urban Runoff 0.56-1.47 0.23-1.07 Coal tar 3.11 1.29

PETROGENIC SOURCES1

No. 2 Fuel Oil & Diesel Fuel >800* 0.38

No 4 Fuel Oil 11.8 0.16 Road paving asphalt 20 <0.11*

West Virginia Coal (2 samples) 11.2, 27.9 0.95, 1.03

POWELL RIVER WATERSHED SEDIMENTS Average of all Sediment Results 22.58 1.01

1Source Neff et. al, 2005,

No studies are available on the chronic toxicity of dissolved PAHs to invertebrates and

very few on acute toxicity. The dissolved acute toxicity studies indicate that PAH

toxicity to invertebrates is inconsistent (in Messinger, 2002). Other research has focused

on the toxicity of PAHs in bottom sediments and found that the toxicity of PAHs are

additive (Swartz, 1999); and, even though the majority of the individual values can be

below PEC screening or other screening levels, there may be enough compounds

measured to have the potential for an additive effect. One method to determine the

combined toxicity potential is to calculate a hazard quotient. A hazard quotient is

calculated by dividing the measured result by the PEC or screening value. Summing the

results provides a hazard index and index values greater than 1.0 can indicate a

potentially toxic situation (Table 7.4) (Ingersoll et. al., 2000). Fourteen VADEQ

monitoring stations had hazard indexes that exceeded 1.0.

The source(s) of the PAHs in the Powell River watershed are not well known at this time.

Additional monitoring has isolated some watersheds with high sediment concentrations

but further monitoring is needed to establish the likely sources of the contaminants.



Concerns were raised regarding the sufficiency of the available data’s ability to determine

accurate pollution load reductions. For this reason Total PAHs are considered a possible

stressor.

The benthic TMDL portion of this report is being presented as a “Phased” TMDL for the

most probable stressor (sediment, see section 7.4) in accordance with EPA guidance and

the state will utilize an adaptive management approach. A revised TMDL document is

planned for submittal to EPA two years from the date that both the EPA Region III has


TMDL. During this two year period while additional TSS data is being collected for the

sediment TMDL additional PAH data will also be collected with the goal of confirming

the source(s) and availability of the sediment PAHs. At the conclusion of the extended

monitoring phase a TMDL for Total PAHs will be developed if deemed necessary.

Identifying and quantifying the sources of PAHs is key to assigning reductions during the

allocation phase and for successful implementation. The Virginia Department of Mines,

Minerals, and Energy’s Division of Mined Land Reclamation (DMLR) will take the lead

in collecting the additional PAH data and with the Total PAH TMDL development

should it be necessary.



Table 7.4 Sediment PAHs hazard quotients* in the Powell River watershed.

PAH Compound PEC1

Wisconsin Screening

Value2 6BPOW178.33

06/18/02 6BPOW123.64

04/28/05 6BPOW170.76

03/29/05 6BPOW179.20

01/26/2006 2-Methyl Naphthalene

0.201 0.557 6.363 9.069 6.965

Acenaphthene 0.089 0.087 ND ND 0.494 Acenaphthylene 0.128 0.004 ND ND ND Anthracene 0.845 0.006 ND ND ND Benzo[a] anthracene

1.05 0.029 0.10 0.221

Benzo[a]pyrene 1.45 0.032 0.05 0.078 0.080 Chrysene 1.29 0.042 0.13 ND 0.255 Dibenz[a,h] anthracene

0.135 0.12 ND ND 0.147

Fluoranthene 2.23 0.019 0.04 0.123 0.224 Fluorene 0.536 0.013 0.10 0.190 Naphthalene 0.561 0.088 1.98 2.565 1.679 Phenanthrene 1.17 0.117 0.65 0.896 Pyrene 1.52 0.028 0.08 0.136 0.28

Hazard Index (sum of Hazard

Quotients)** 1.142 9.493 11.971 11.431

*Hazard Quotients were calculated as the ratio of measured concentration to the PEC or other available screening value for that compound. **Hazard Index was calculated as the sum of all hazard quotients for individual PAH compounds. Hazard Quotients or Hazard Indices that exceed 1.0 indicate that toxic effects on benthos are possible. Hazard ratios were not calculated for estimated values, A bold hazard index exceeds 1.0, PAH compounds exhibit similar exposure pathways and modes of action so are assumed to be additive in effect, 1PEC Probable Effect Concentration (MacDonald et al., 2000) , 2Wisconsin aquatic life sediment screening value (Wisconsin 2003) all values are in mg/Kg, ND – Not Detected.



Table 7.4 Sediment PAHs hazard quotients* in the Powell River watershed (cont.).

PAH Compound PEC

Wisconsin screening

value 6BCAL001.57

6/2/2009 6BPOW115.51

6/3/2009 6BRIN000.31

6/2/2009 6BPOW179.20

6/1/2009 2-MetNap 0.201 7.463 7.463 7.960 7.463

Acenaphthene 0.089 0.213 0.180 0.157 0.146 Acenaphthylene 0.128 0.034 0.000 0.258 0.000

Anthracene 0.845 0.050 0.041 0.022 0.028 Benzo[a]anthracene 1.05 0.133 0.042 0.060 0.133

Benzo[a]pyrene 1.45 0.041 0.015 0.024 0.083 Chrysene 1.29 0.163 0.042 0.116 0.171

Dibenz[a,h]anthracene 0.135 0.074 0.036 0.054 0.104 Fluoranthene 2.23 0.143 0.023 0.067 0.139

Fluorene 0.536 0.080 0.095 0.090 0.076 Naphthalene 0.561 1.783 1.961 1.961 2.139 Phenanthrene 1.17 0.718 0.547 0.752 0.667

Pyrene 1.52 0.197 0.041 0.099 0.191 Hazard Index (sum of Hazard

Quotients) 11.09 10.49 11.62 11.34





PAH Compound PEC

Wisconsin screening

value 6BPLL000.27

6/2/2009 6BPOW193.38

6/2/2009 6BPOW183.55

6/2/2009 6BPIG000.04

6/2/2009 2-MetNap 0.201 0.234 1.443 4.179 5.473

Acenaphthene 0.089 0.000 0.247 0.000 0.000 Acenaphthylene 0.128 0.000 0.000 0.000 0.000

Anthracene 0.845 0.009 0.130 0.021 0.026 Benzo[a]anthracene 1.05 0.042 0.181 0.051 0.062

Benzo[a]pyrene 1.45 0.030 0.103 0.024 0.028 Chrysene 1.29 0.038 0.178 0.053 0.078

Dibenz[a,h]anthracene 0.135 0.056 0.163 0.050 0.059 Fluoranthene 2.23 0.067 0.260 0.058 0.049

Fluorene 0.536 0.000 0.060 0.069 0.052 Naphthalene 0.561 0.250 0.250 1.105 1.283 Phenanthrene 1.17 0.043 0.453 0.385 0.436

Pyrene 1.52 0.049 0.309 0.079 0.086 Hazard Index (sum of Hazard

Quotients) 0.82 3.78 6.08 7.63





PAH Compound PEC

Wisconsin screening

value 6BLOC001.05

6/3/2009 6BBLK000.13

6/3/2009 6BPOW197.2

1 6/3/2009 2-MetNap 0.201 5.970 1.642 0.945

Acenaphthene 0.089 0.404 0.000 0.000 Acenaphthylene 0.128 0.078 0.000 0.000

Anthracene 0.845 0.082 0.000 0.006 Benzo[a]anthracene 1.05 0.400 0.010 0.025

Benzo[a]pyrene 1.45 0.269 0.004 0.008 Chrysene 1.29 0.488 0.019 0.035

Dibenz[a,h]anthracene 0.135 0.889 0.000 0.000 Fluoranthene 2.23 0.673 0.006 0.013

Fluorene 0.536 0.110 0.028 0.021 Naphthalene 0.561 1.283 0.357 0.157 Phenanthrene 1.17 1.111 0.154 0.214

Pyrene 1.52 0.789 0.012 0.022

Hazard Index (sum of Hazard Quotients) 12.55 2.23 1.45




7.4 Most Probable Stressor(s)

Probable stressor(s) in the Powell River are reported in Table 7.5.

Table 7.5 Probable stressor(s) in the Powell River. Parameter Location in Document

Sediment section 7.4.1

7.4.1 Sediment

Total suspended solids (TSS) concentrations did not exceed the 90th percentile screening

value (30 mg/L) at the three VADEQ ambient monitoring stations in more than 10% of

the samples collected. However there were very high concentrations recorded at each

station 73 mg/L, 108 mg/L and 112 mg/L at 6BPOW138.91, 6BPOW165.78 and

6BPOW179.20 respectively (Figures 7.33, 7.34 and 7.35). Indicating that excessive

solids are a periodic problem in the Powell River.

The habitat data at six of the seven VADEQ benthic monitoring stations indicates

marginal and in one case a poor Embeddedness and/or Pool Sediment scores. Table 7.6

summarizes the low Embeddedness and Pool Sediment scores at the Powell River benthic

monitoring stations. Based on the consistently low Embeddedness and Pool Sediment

scores and occasional high TSS concentrations sediment is considered a most probable

stressor in the Powell River. Modeling and subsequent allocations will focus on total

suspended solids.



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Table 7.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the Powell River.

Habitat Metric

6BPOW120.12 Dec-97

6BPOW120.12Jun-99

6BPOW156.57Oct-01

6BPOW158.45 Jun-96

6BPOW166.92Nov-98

Embeddedness 8 9 7 6 6 Pool Sediment 10 OK 8 5 7 OK – score was in the satisfactory range.

Table 7.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the Powell River (cont.).

Habitat Metric

6BPOW166.97 May-06

6BPOW179.20Oct-06

6BPOW180.72Nov-97

6BPOW180.72 Dec-03

6BPOW184.19Apr-07

Embeddedness 8 9 3 7 8 Pool Sediment 9 10 7 OK 10 OK – score was in the satisfactory range.

Table 7.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the Powell River (cont.).

Habitat Metric

6BPOW120.12 Oct-08

6BPOW179.20Sep-08

Embeddedness 10 OK Pool Sediment 10 9 OK – score was in the satisfactory range.


TMDL ENDPOINT-NORTH FORK POWELL RIVER 8-1

8. TMDL ENDPOINT: STRESSOR IDENTIFICATION – NORTH FORK POWELL RIVER

8.1 Stressor Identification – North Fork Powell River

The North Fork Powell River begins in western Lee County Virgnia and travels in a

southwesterly direction for approximately 25 miles through Lee Couny before reaching

the confluence with the Powell River. There is one impaired benthic segment on the

mainstem of the North Fork Powell River on Virginia’s 303(d) list. The segment begins

at the North Fork Powell River’s confluence with Straight Creek and continues

downstream to North Fork Powell River and Powell River confluence for a total of 6.25

stream miles (VADEQ segment identification number VAS-P20R_PWL01A00). In this

segment VADEQ benthic monitoring stations 6BPLW005.46 and 6BPWL004.40

indicated impairment and the segment was placed on the 1998 303(d) list and has

remained on subsequent lists.

The stressor analysis procedure for North Fork Powell River was the same as the one

used for the Powell River, described in Chapter 7 Section 7.1, and in the Glossary.

8.2 Non-Stressors

Non-stressors in the North Fork Powell River are reported in Table 8.1.

Table 8.1 Non-Stressors in the North Fork Powell River.

Parameter Location in Document

Low dissolved oxygen section 8.2.1 Nutrients section 8.2.2 Toxics (ammonia, PCBs and pesticides) section 8.2.3 Metals section 8.2.4 Temperature section 8.2.5 Field pH section 8.2.6 Organic matter section 8.2.7





8-2 TMDL ENDPOINT-NORTH FORK POWELL RIVER

target(s) are protective of water quality standards (WQS), then the Commonwealth will

make use of the option to refine the TMDLs for re-submittal to EPA for approval.


Dissolved oxygen (DO) concentrations were well above the WQS of 4.0 mg/L at all three

VADEQ ambient monitoring stations in the vicinity of the impaired VADEQ benthic

monitoring stations (6BPWL001.49, 6BPWL004.10 and 6BPWL006.59 (Figures 8.1, 8.2

and 8.3). Low dissolved oxygen is considered a non-stressor.

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Figure 8.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPWL001.49.



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8.2.2 Nutrients

Total phosphorus (TP) concentrations were very low at all three VADEQ ambient

monitoring stations in the vicinity of the impaired VADEQ benthic monitoring stations.

No values out of 120 samples exceeded the VADEQ screening value of 0.2 mg/L,

Figures 8.4 and 8.5. Twenty three percent of the 96 samples collected at 6BPWL001.49

were below the minimum laboratory detection level. Half of the 12 samples collected at

6BPWL004.10 were below the minimum laboratory detection level. Nitrate nitrogen

concentrations were also low and all of the values at all three monitoring stations were

below the 90th percentile screening value of 1.23 mg/L (Figures 8.6, 8.7 and 8.8).

Nutrients are considered non-stressors.

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Figure 8.4 Total phosphorus concentrations at VADEQ station 6BPWL001.49.



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Figure 8.5 Total phosphorus concentrations at VADEQ station 6BPWL004.10.

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Figure 8.6 Nitrate-nitrogen concentrations at VADEQ station 6BPWL001.49.



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8.2.3 Toxics (ammonia, PCBs and pesticides)

Seventy percent of the ammonia (NH3/NH4) samples collected in the North Fork Powell

River were below the minimum laboratory level of detection (0.04 mg/L). The remaining

values were well below VADEQ’s chronic WQS. Only VADEQ ambient monitoring

station 6BPWL001.49 had ammonia values that exceeded the minimum laboratory

detection level (Figure 8.9). Both the chronic and acute ammonia WQSs are dependent

on the pH and temperature at the time of sampling. Ammonia is considered a non-

stressor in the North Fork Powell River. Sediment pesticide and PCB values were below

established screening levels (Tables 6.71, 6.74, and 6.75) and are also considered non-

stressors.

0%

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d Va

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QS

Exceeds Chronic Water Quaity Standard

Figure 8.9 Ammonia-nitrogen concentrations at VADEQ station 6BPWL001.49.



8.2.4 Metals

This section discusses VADEQ water quality monitoring for metals dissolved in the

water column and metals in sediment. All sediment metal values were below the PEC

values (Tables 6.70 and 6.73).

Water column dissolved metals were sampled at one VADEQ monitoring station on the

North Fork Powell River and all results were below the appropriate VADEQ WQS, Table

6.77. Not all of the metals listed have established VADEQ or USEPA WQSs. Dissolved

metals WQSs are dependent on the hardness in the stream at the time of sampling.

Based on the results of the dissolved and sediment metals data, metals are considered

non-stressors.

8.2.5 Temperature

The VADEQ maximum temperature standard for the North Fork Powell River is 31.0°C.

The maximum temperature recorded at the three VADEQ ambient monitoring stations on

the North Fork Powell River was 24.2°C (Figures 8.10, 8.11 and 8.12). Temperature is

considered a non-stressor in the North Fork Powell River.



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Figure 8.10 Temperature measurements at VADEQ station 6BPWL001.49.

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8.2.6 Field pH

Field pH values were within the minimum and maximum VADEQ WQSs at all three

VADEQ monitoring stations on the North Fork Powell River (Figures 8.13, 8.14 and

8.15). Therefore, field pH is considered a non-stressor in the North Fork Powell River.



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d pH

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ts)

.



Figure 8.13 Field pH measurements at VADEQ station 6BPWL001.49.

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.



Figure 8.14 Field pH measurements at VADEQ station 6BPWL004.10



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.



Figure 8.15 Field pH measurements at VADEQ station 6BPWL006.59.

8.2.7 Organic matter


dissolved and suspended organic matter. TVS concentrations exceeded the 90th

percentile screening concentration (63 mg/L) in four percent, of the samples collected at

VADEQ ambient monitoring station 6BPWL001.49 (TVS was not collected at

6BPWL004.10 and 6BPWL006.59) (Figure 8.16). Total organic carbon (TOC)

concentrations exceeded the 90th percentile screening value (4 mg/L) in three percent of

the samples collected at station 6BPWL001.49 (Figure 8.17) (TOC was not collected at

6BPWL004.10 and 6BPWL006.59). Chemical oxygen demand (COD) concentrations

exceeded the 90th percentile screening value (14 mg/L) in two percent of the samples

collected at 6BPWL001.49, Figure 8.18 (COD was not collected at 6BPWL004.10 and

6BPWL006.59). Total kjeldahl nitrogen (TKN) is a measure of the amount or organic

nitrogen in the stream. TKN concentrations exceeded the 90th percentile screening value

(0.4 mg/L) in two percent of the samples collected at 6BPWL001.49 (Figure 8.19) (TKN

was not collected at 6BPWL004.10 and 6BPWL006.59).



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.


Figure 8.16 Total organic solids concentrations at VADEQ monitoring station 6BPWL001.49.

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Figure 8.17 Total organic carbon concentrations at VADEQ monitoring station 6BPWL001.49.



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Figure 8.18 Chemical oxygen demand concentrations at VADEQ monitoring station 6BPWL001.49.

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Figure 8.19 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPWL001.49.



The assemblage for all of the benthic stations on the North Fork Powell River from the

VADEQ Ecological Data Application System (EDAS) database were examined, and

Hydropsychidae (netspinning caddisflies) were found not to be the most dominant or a

very significant family at each monitoring station. The average contribution was 5.4%

and the range was 1.7% - 12.7%. Hydropsychidae are often associated with high

concentrations of organic matter in streams. This corresponds very well with the

chemical data presented above and confirms that organic matter is not a stressor in the

North Fork Powell River.


Possible stressors in the North Fork Powell River are reported in Table 8.2.

Table 8.2 Possible Stressors in the North Fork Powell River. Parameter Location in Document

Sulfate section 8.3.1 Conductivity/total dissolved solids (TDS) section 8.3.2 Total PAHs (Polyaromatic Hydrocarbons) section 8.3.3

8.3.1 Sulfate

Sulfate concentrations exceeded the 90th percentile screening value (76 mg/L) in more

than 10% of the samples collected at all VADEQ ambient monitoring station

6BPWL001.49 (Sulfate was not sampled at 6BPWL004.10 and 6BPWL006.59) (Figure

8.20). The USEPA used sulfate concentrations as an indicator of impaired

macroinvertebrate communities in mid-Atlantic highland streams (Klemm et al., 2001).

Other studies note that sulfate is a reliable indicator of mining activity and is often linked

to depressed benthic health, but, by itself, has not been shown to actually cause a

reduction in the health of benthic communities (Merricks, 2003). Sulfate is, however, a

principle component of total dissolved solids, which have been shown to impair benthic

macroinvertebrate communities. There is a public water supply WQS of 250 mg/L, but

this is for taste and odor control and does not apply to aquatic life. Therefore sulfate is

considered a possible stressor.



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te (m

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) .


Figure 8.20 Sulfate concentrations at VADEQ monitoring station 6BPWL001.49.

8.3.2 Conductivity/Total dissolved solids (TDS)

Conductivity is a measure of the electrical potential in the water based on the ionic

charges of the dissolved compounds that are present. TDS is a measure of the actual

concentration of the dissolved ions, dissolved metals, minerals, and dissolved organic

matter in water. Dissolved ions can include sulfate, calcium carbonate, chloride, etc.

Therefore, even though they are two different measurements, there is a direct correlation

between conductivity and TDS. In the North Fork Powell River data set, there was a

Pearson Product Moment Correlation of 0.995 between conductivity and TDS.

High conductivity values have been linked to poor benthic health (Merricks, 2003) and

elevated conductivity is common with land disturbance and mine drainages. A recent

report on the effects of surface mining on headwater stream biotic integrity in Eastern

Kentucky noted that one of the most significant stressors in these watersheds was

elevated TDS (Pond, 2004). Elevated TDS concentrations impact pollution sensitive



mayflies the most. Figure 8.21 from this report shows that “drastic reductions in mayflies

occurred at sites with conductivities generally above 500 μmhos/cm” (Pond, 2004).

Figure 8.21 The relationship between %Ephemeroptera and conductivity from reference and mined sites (Pond, 2004).

Pond speculated that the increased salinity may irritate the gill structures on mayflies and

inhibit the absorption of oxygen, but research has not confirmed this. A typical reference

station in this part of the state can be expected to have at least 50% mayflies out of the

total assemblage. The results of a VADEQ benthic surveys in North Fork Powell River

at four VADEQ benthic monitoring stations indicated that sensitive mayflies made up

between 2% - 5% of the total benthic assemblage. The members of the more pollution

tolerant families (Caenidae, Baetidae, and Isonychiidae) were not included in this

calculation. In the development of both the Virginia and West Virginia Stream Condition

Indices, the reference streams used had conductivity levels that did not exceed 500

μmhos/cm. In the absence of a Virginia WQS, the 90th percentile screening value of 402

μmhos/cm was used. Conductivity values at all three VADEQ stations consistently

exceeded the 90th percentile screening value (402 μmhos/cm) in 40%, 57% and 25% at

VADEQ ambient monitoring stations 6BPWL001.49, 6BPWL004.10 and 6BPWL006.59

(Figures 8.22, 8.23 and 8.24).



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Figure 8.22 Conductivity measurements at VADEQ station 6BPWL001.49.

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The TDS 90th percentile screening value was 260 mg/L. TDS concentrations consistently

exceeded this value in 46% and 50% of the samples at all the two VADEQ ambient

monitoring stations where TDS was sampled, 6BPWL001.49 and 6BPWL004.10

(Figures 8.25 and 8.26)



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Figure 8.25 TDS concentrations at VADEQ station 6BPWL001.49.

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Figure 8.26 TDS concentrations at 6BPWL004.10.



TDS concentrations can be harmful to aquatic organisms without causing death. Aquatic

organisms balance water and internal ions through a number of different mechanisms.

Therefore, high concentrations and significant changes in TDS over long periods of time

can place a lot of stress on the organisms. The resulting chronic stress affects processes

such as growth and reproduction. Sudden large spikes in TDS concentration can be fatal.

A study of TDS toxicity in a coal-mining watershed in southeastern Ohio found the

lowest observed effect concentration (LOEC) on the test organism Isonychia bicolor (a

species of Mayfly) was 1,066 mg/L (Kennedy, 2002). The author carefully noted that

this concentration was specific to the watershed studied, but noted that similar studies

with the same test organism and TDS with varying ionic compositions were toxic

between 1,018 and 1,783 mg/L (Kennedy, 2002). Kennedy also cited a study that

suggested that aquatic organisms should be able to tolerate TDS concentrations up to

1,000 mg/L; however, the test organism used was Chironomous tentans, which is

considerably more pollution tolerant than Isonychia bicolor (Kennedy, 2002). Research

also indicates that the likely mechanism(s) of TDS benthic macroinvertebrate mortality is

from gill and internal tissue dehydration, salt accumulation and compromised

osmoregulatory function. In fact, the rate of change in TDS concentrations may be more

toxic to benthic macroinvertebrates than the TDS alone (Kennedy, 2002).

It is clear from the data available that conductivity and TDS values are high. The North

Fork Powell River is considered by the VADEQ to be a fifth order stream at the impaired

VADEQ benthic monitoring stations. Larger streams tend to be comprised of benthic

organisms that are a little more facultative than lower order high gradient streams in the

Central Appalachians. These organisms are generally somewhat more tolerant of higher

TDS concentrations. In addition, a TDS TMDL has been developed for Straight Creek, a

tributary to the North Fork Powell River. Straight Creek watershed contains most of the

mining lands within the North Fork Powell River watershed and is the source of most of

the TDS in the North Fork Powell River. The biological monitoring station on the North

Fork Powell River upstream of the confluence with Straight Creek has not shown

impairment to date. Implementation of this TMDL will result in decreasing TDS

concentrations in the North Fork Powell River. Therefore, conductivity and TDS are

considered possible stressors in the North Fork Powell River.



8.3.3 Total PAHs (Polycyclic Aromatic Hydrocarbons)

PAHs are a group of chemicals that occur naturally in coal, crude oil, and gasoline.

There are more than 100 different PAHs. PAHs generally occur as complex mixtures,

not as single compounds. PAHs are also present in products made from fossil fuels, such

as coal-tar pitch, creosote, and asphalt. When coal is converted to natural gas, PAHs can

be released. Therefore, some coal-gasification sites may have elevated levels of PAHs.

PAHs also can be released into the air during the incomplete burning of coal, oil, gas, or

any organic substance. When the burning process is less efficient, more PAHs are given

off. Forest fires and volcanoes can produce PAHs naturally. Once released into the

aquatic environment, degradation by micro-organisms is often slow, leading to their

accumulation in exposed sediments, soils, aquatic and terrestrial plants, fish, and

invertebrates. In terms of human health, prolonged exposure to PAHs can have negative

effects on individuals exposed to mixtures of PAHs. Many useful products such as

mothballs, blacktop, and creosote wood preservatives contain PAHs. They are also found

at low concentrations in some special-purpose skin creams and anti-dandruff shampoos

that contain coal tars.

The 16 PAHs that are listed below are the most commonly sampled, for the following

reasons: there is more information available on these PAHs; they are suspected to be

more harmful than some of the other PAHs; they exhibit harmful effects that are

representative of the PAHs; there is a greater chance of exposure to these PAHs than to

the others and in relation to all of the PAHs analyzed (Agency For Toxic Substances and

Disease Registry, August 1995). Sixteen PAHs are currently identified on the USEPA

National Priority List (NPL) hazardous waste list. The list is as follows:

Acenaphthene benzo[b]fluoranthene Fluoranthene Acenaphthylene benzo[g,h,i]perylene Fluorene Anthracene benzo[j]fluoranthene Indeno[1,2,3-c,d]pyrene benz[a]anthracene benzo[k]fluoranthene Phenanthrene Benzo[a]pyrene chrysene Pyrene dibenz[a,h]anthracene

High concentrations of PAHs were found in a sediment samples taken by the VADEQ at

several sites and at different times on the North Fork Powell River (Tables 6.72). The



PAHs that consistently exceed Virginia screening levels are 2-methyl naphthalene and

naphthalene. The exact source or sources of these compounds is not known at the present

time. Most of the naphthalene that enter the environment are from the burning of wood

and fossil fuels. Naphthalene is typically a white solid substance that evaporates easily.

It is used in mothballs, moth flakes and tar camphor. Both coal and petroleum naturally

contain naphthelene. The primary commercial use of naphthelene is the making of

polyvinyl chloride plastics. Naphthalene is also used in making dyes, resins, leather

tanning products and carbaryl (an insecticide known commercially as sevin). Because

naphthalene is so volatile it is usually gone from rivers or lakes within two weeks. In

addition, it binds very weakly to soil and sediments, (Agency For Toxic Substances and

Disease Registry, August 2005).

MapTech reviewed sediment PAH data collected through VADEQ’s Fish Tissue and

Sediment Program from 1995 – 2006. In this dataset only six out of 500 naphthalene

samples exceeded the Probable Effect Concentration (PEC) that VADEQ uses as a

screening value (561 ug/Kg). None of the six values were in the coal fields region of

southwestern Virginia (the naphthalene values in the North Fork Powell River that did

exceed the PEC screening value were collected by VADEQ regional monitoring staff as

part of special studies not related to the statewide Fish Tissue and Sediment Program).

However, 23 naphthalene concentrations exceeded the 95th percentile concentration for

the dataset (130 ug/Kg) and 35% (8) of these samples were in the coalfields region

(Figure 8.27).



Virginia DEQ Naphthalene Sediment Monitoring (1995 - 2006) From the VIMS Laboratory

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Note: Red symbols exceed the 95th percentile

90 0 90 180 Miles

S

N

EW

Naphthalene (ug/kg)# 0 - 52# 52 - 130# 131 - 364# 364 - 975# 975 - 2,216

Virginia Counties and Cities

Figure 8.27 Naphthalene concentrations in bottom sediment in Virginia.

Studies on PAH concentrations in bottom sediment in coal mining areas of the United

States are very limited. In 2002 the US Geological Survey published a report on PAHs in

bottom sediment in the Kanawha River Basin in West Virginia. The investigation

focused on 12 PAHs with criteria (Probable Effect Levels) established by the Canadian

Council of Ministers of the Environment. Six of the twelve PAH compounds (including

naphthalene) had concentrations that exceeded the Probable Effect Level (PEL)

concentration. More importantly the USGS found a significant relationship between the

sum of all the PAHs measured and coal mined watersheds where coal production

exceeded 20 tons per square mile (Messinger, 2002).

PAH concentrations in sediment are typically derived from three sources: naturally

occurring in fossil fuels (petrogenic), those that result from the burning of organic matter



or combustion (pyrogenic), and the transformation of precursors in the environment by

rapid biological/chemical processes (biogenic PAH). PAHs resulting from the biogenic

processes usually do not contribute nearly as much to the total mass of PAH in the

sediment as the inputs from anthropogenic sources. It is sometimes possible to look at

the ratios of various PAH compounds in the sediment to distinguish between petrogenic

and pyrogenic sources (Neff et al., 2005). One technique is to look at the ratio of

phenanthrene and anthracene (PH/AN). Pyrogenic sources typically have ratios less than

5, while petrogenic sources are usually greater than 5. Similarly, the ratio of fluoranthene

to pyrene (FL/PY) is usually just below or greater than one (1) if the source is pyrogenic

but, if it is substantially less than one, then the source is usually petrogenic (Neff et al.,

2005). Table 8.3 provides examples of these two ratios from various sources and the

average from the sampling events by VADEQ in the Powell River sediments. The ratios

for the North Fork Powell River sediments are inconsistent falling into both categories.

Similar attempts by the USGS to determine the source(s) of the PAHs in the Kanawha

River Basin report were also inconsistent (Messinger, 2002).

Table 8.3 Ratios of PAH isomers from various sources and the North Fork Powell River watershed sediments

Source PH/AN Ratio FL/PY Ratio PYROGENIC SOURCES1

Auto exhaust soot 1.79 0.9 Highway dust 4.7 1.4 Urban Runoff 0.56-1.47 0.23-1.07 Coal tar 3.11 1.29

PETROGENIC SOURCES1

No. 2 Fuel Oil & Diesel Fuel >800* 0.38

No 4 Fuel Oil 11.8 0.16 Road paving asphalt 20 <0.11*

West Virginia Coal (2 samples) 11.2, 27.9 0.95, 1.03

NORTH FORK POWELL RIVER WATERSHED SEDIMENTS

Average of all Sediment Results 8.38 1.18

1Source Neff et. al, 2005,



No studies are available on the chronic toxicity of dissolved PAHs to invertebrates and

very few on acute toxicity. The dissolved acute toxicity studies indicate that PAH

toxicity to invertebrates is inconsistent (in Messinger, 2002). Other research has focused

on the toxicity of PAHs in bottom sediments and found that the toxicity of PAHs are

additive (Swartz, 1999); and, even though the majority of the individual values can be

below PEC screening or other screening levels, there may be enough compounds

measured to have the potential for an additive effect. One method to determine the

combined toxicity potential is to calculate a hazard quotient. A hazard quotient is

calculated by dividing the measured result by the PEC or screening value. Summing the

results provides a hazard index and index values greater than 1.0 can indicate a

potentially toxic situation (Table 8.4) (Ingersoll et. al., 2000). Two VADEQ monitoring

stations had hazard indexes that exceeded 1.0 (6BPWL001.49 and 6BPPWL004.10).

The source(s) of the PAHs in the North Fork Powell River watershed are not well known

at this time. Additional monitoring has isolated some watersheds with high sediment

concentrations but further monitoring is needed to establish the likely sources of the

contaminants. Concerns were raised regarding the sufficiency of the available data’s

ability to determine accurate pollution load reductions. For this reason Total PAHs are

considered a possible stressor.

The benthic TMDL portion of this report is being presented as a “Phased” TMDL for the

most probable stressor (sediment, see section 8.4) in accordance with EPA guidance and

the state will utilize an adaptive management approach. A revised TMDL document is

planned for submittal to EPA two years from the date that both the EPA Region III has


TMDL. During this two year period while additional TSS data is being collected for the

sediment TMDL additional PAH data will also be collected with the goal of confirming

the source(s) and availability of the sediment PAHs. At the conclusion of the extended

monitoring phase a TMDL for Total PAHs will be developed if deemed necessary.

Identifying and quantifying the sources of PAHs is key to assigning reductions during the

allocation phase and and for successful implementation. The Virginia Department of

Mines, Minerals, and Energy’s Division of Mined Land Reclamation (DMLR) will take



the lead in collecting the additional PAH data and with the Total PAH TMDL

development should it be necessary.

Table 8.4 Sediment PAHs hazard quotient* in the North Fork Powell River on.

PAH Compound PEC1

Wisconsin Screening

Value2 6BPWL002.48

06/18/2002 6BPWL001.49

01/26/2006 6BPWL004.10

01/26/2006 2-Methyl Naphthalene 0.201 1.169 5.308 1.62 Acenaphthene 0.089 0.119 0.483 0.00 Acenaphthylene 0.128 0.027 0.00 0.083 Anthracene 0.845 0.028 0.00 0.00 Benzo[a]anthracene 1.05 0.247 0.154 0.060 Benzo[a]pyrene 1.45 0.254 0.076 0.022 Chrysene 1.29 0.198 0.204 0.068 Dibenz[a,h]anthracene 0.318 0.135 0.609 0.117 0.074 Fluoranthene 2.23 0.165 0.178 0.07 Fluorene 0.536 0.031 0.101 0.032 Naphthalene 0.561 0.235 1.663 0.414 Phenanthrene 1.17 0.223 0.509 0.158 Pyrene 1.52 0.218 0.215 0.081

Hazard Index (sum of Hazard

Quotients)** 3.524 9.008 2.686

*Hazard Quotients were calculated as the ratio of measured concentration to the PEC or other available screening value for that compound. **Hazard Index was calculated as the sum of all hazard quotients for individual PAH compounds. Hazard Quotients or Hazard Indices that exceed 1.0 indicate that toxic effects on benthos are possible. Hazard ratios were not calculated for estimated values, A bold hazard index exceeds 1.0, PAH compounds exhibit similar exposure pathways and modes of action so are assumed to be additive in effect, 1PEC Probable Effect Concentration (MacDonald et al., 2000) and 2Wisconsin aquatic life sediment screening value (Wisconsin, 2003).

8.4 Most Probable Stressors

Probable stressors in the North Fork Powell River are reported in Table 8.5.

Table 8.5 Probable stressors in the North Fork Powell River. Parameter Location in Document

Sediment section 8.4.1

8.4.1 Sediment

Total suspended solids (TSS) concentrations did not exceed the 90th percentile screening

value (30 mg/L) at the three VADEQ ambient monitoring stations in more than 10% of

the samples collected (Figure 8.28). Only VADEQ ambient monitoring station



6BPWL001.49 had more than nine samples exceed the minimum laboratory detection

level.

The habitat data at all four VADEQ benthic monitoring stations indicates marginal Pool

Sediment scores. Table 8.6 summarizes the low Pool Sediment scores at the North Fork

Powell River VADEQ benthic monitoring stations (see Table 6.23 for the ranges of

habitat scores, scores below 11 are considered unacceptable). Embeddedness is generally

a better indicator of sediment problems in the riffle areas where the benthic organisms are

collected for analysis. Consistently low Pool Sediment scores indicate a sediment

problem in the stream. Based on the consistently low Pool Sediment scores sediment is

considered a most probable stressor in the North Fork Powell River. Modeling and

subsequent allocations will focus on total suspended solids.

0

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45

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Tot

al su

spen

ded

solid

s (m

g/L

) .


Figure 8.28 TSS concentrations at VADEQ station 6BPPWL001.49.



Table 8.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the North Fork Powell River. Habitat Metric 6BPWL000.06

5/02 6BPWL000.06

10/02 6BPWL001.93

5/06 6BPWL004.40

12/03 Embeddedness OK OK OK OK Pool Sediment 6 9 10 10

OK – score was satisfactory.

Table 8.6 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the North Fork Powell River (cont).

Habitat Metric

6BPWL004.40 06/04

6BPWL006.16 6/04

6BPWL004.40 5/08

Embeddedness OK OK 10 Pool Sediment 10 6 10 OK – score was satisfactory.


TMDL ENDPOINT-SOUTH FORK POWELL RIVER 9-1

9. TMDL ENDPOINT: STRESSOR IDENTIFICATION – SOUTH FORK POWELL RIVER

9.1 Stressor Identification – South Fork Powell River

The South Fork Powell River begins in northeastern Lee County Virgnia and travels in a

west southwest direction for approximately 15 miles through Lee Couny before reaching

the confluence with the Powell River. There is one impaired benthic segment on the

mainstem of the South Fork Powell River on the Virginia’s 303(d) list. The segment

begins at the South Fork Powell River’s confluence with Beaverdam Creek and continues

downstream to South Fork Powell River and Powell River confluence for a total of 5.61

stream miles. In this segment VADEQ benthic monitoring station 6BPLL002.55

indicated impairment and the segment was placed on the 1998 303(d) list and it has

remained on subsequent lists.

The stressor analysis procedure for the South Fork Powell River was the same as the one

used for the Powell River, described in Chapter 7 Section 7.1, and in the Glossary.

9.2 Non-Stressors

Non-stressors in the South Fork Powell River are reported in Table 9.1.

Table 9.1 Non-Stressors in the South Fork Powell River.

Parameter Location in Document

Low dissolved oxygen section 9.2.1 Nutrients section 9.2.2 Toxics (ammonia, PCBs, PAHs and Pesticides) section 9.2.3 Metals section 9.2.4 Temperature section 9.2.5 Field pH section 9.2.6 Organic matter section 9.2.7 Sulfate section 9.2.8 Conductivity/total dissolved solids (TDS) section 9.2.9





9-2 TMDL ENDPOINT- SOUTH FORK POWELL RIVER

target(s) are protective of water quality standards, then the Commonwealth will make use

of the option to refine the TMDLs for re-submittal to EPA for approval.


Dissolved oxygen (DO) concentrations were well above the water quality standard of 4.0

mg/L at the two VADEQ ambient monitoring stations in the vicinity of the impaired

benthic monitoring stations (6BPLL004.24 and 6BPLL006.38 (Figures 9.1 and 9.2).

Low dissolved oxygen is considered a non-stressor.

0.0

2.0

4.0

6.0

8.0

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07/0

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Dis

solv

ed O

xyge

n (m

g/L

) .


Figure 9.1 Dissolved oxygen concentrations at VADEQ monitoring station 6BPLL004.24.



0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

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Dis

solv

ed O

xyge

n (m

g/L

) .


Figure 9.2 Dissolved oxygen concentrations at VADEQ monitoring station 6BPLL006.38.

9.2.2 Nutrients

Total phosphorus (TP) concentrations were very low at both VADEQ ambient

monitoring stations in the vicinity of the impaired benthic monitoring stations. No values

out of 47 samples exceeded the VADEQ screening value of 0.2 mg/L, Figures 9.3 and

9.4. Nitrate nitrogen concentrations were also low and all of the values at both ambient

monitoring stations were below the 90th percentile screening value of 1.23 mg/L (Figures

9.5 and 9.6). Nutrients are considered non-stressors.



0.00

0.05

0.10

0.15

0.20

0.25

03/9

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05/0

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06/0

6

07/0

7

Tot

al p

hosp

horu

s (m

g/L

) .


Figure 9.3 Total phosphorus concentrations at VADEQ station 6BPLL004.24.

0.00

0.05

0.10

0.15

0.20

0.25

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Tot

al p

hosp

horu

s (m

g/L

) .


Figure 9.4 Total phosphorus concentrations at VADEQ station 6BPLL006.38.



0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

07/0

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09/0

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03/0

4

05/0

4

Tot

al n

itrat

e ni

trog

en (m

g/L

) .


Figure 9.5 Nitrate-nitrogen concentrations at VADEQ station 6BPLL004.24.

0.0

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Tot

al n

itrat

e ni

trog

en (m

g/L

) .


Figure 9.6 Nitrate-nitrogen concentrations at VADEQ station 6BPLL006.38.



9.2.3 Toxics (ammonia, PAHs, PCBs and pesticides)

Ninety four percent of the ammonia (NH3/NH4) samples collected in the South Fork

Powell River were below the minimum laboratory level of detection (0.04 mg/L). The

remaining values were well below the chronic water quality standard. Neither ambient

monitoring station had more than nine samples exceed the minimum laboratory detection

level. Both the chronic and acute ammonia water quality standards are dependent on the

pH and temperature at the time of sampling. Ammonia is considered a non-stressor in the

South Fork Powell River. Sediment pesticide, PAHs and PCB values were below

screening values and/or minimum laboratory detection levels and are also considered

non-stressors.

9.2.4 Metals

This section discusses VADEQ water quality monitoring for sediment metals (dissolved

metals were not collected in the South Fork Powell River). All sediment metal values

were below the PEC values (Table 6.78). Based on the results of the sediment metals

data, metals are considered non-stressors.

9.2.5 Temperature

The maximum temperature standard for the South Fork Powell River is 31.0°C. The

maximum temperature recorded at both VADEQ ambient monitoring stations on the

South Fork Powell River was 23.72°C (Figures 9.7 and, 9.8). Temperature is considered

a non-stressor in the South Fork Powell River.



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35

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Tem

pera

ture

(0 C)


Figure 9.7 Temperature measurements at VADEQ station 6BPLL004.24.

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Tem

pera

ture

(0 C)

.

DEQ standard = 310C

Figure 9.8 Temperature measurements at VADEQ station 6BPLL006.38.



9.2.6 Field pH

Field pH values were within the minimum and maximum water quality standards at both

VADEQ ambient monitoring stations on the South Fork Powell River (Figures 9.9 and

9.10). Therefore, field pH is considered a non-stressor in the South Fork Powell River.

4.0

5.0

6.0

7.0

8.0

9.0

10.0

07/0

3

08/0

4

09/0

5

Fiel

d pH

(std

uni

ts)

.



Figure 9.9 Field pH measurements at VADEQ station 6BPLL004.24.



4.0

5.0

6.0

7.0

8.0

9.0

10.0

08/0

3

09/0

4

Fiel

d pH

(std

uni

ts)

.



Figure 9.10 Field pH measurements at VADEQ station 6BPLL006.38

9.2.7 Organic matter


dissolved and suspended organic matter. TVS concentrations did not exceed the 90th

percentile screening concentration (63 mg/L) in any of the samples collected at VADEQ

ambient monitoring stations 6BPLL004.24 and 6BPLL006.38 (Figures 9.11 and 9.12).

Only two total organic carbon (TOC) samples were collected at 6BPLL004.24 and

neither exceeded the 90th percentile screening value (4 mg/L) (TOC was not collected at

6BPLL006.38). Eight chemical oxygen demand (COD) samples were collected at

6BPLL006.38 and none of them exceeded the 90th percentile screening value (14 mg/L)

(COD was not collected at 6BPLL006.38). Total kjeldahl nitrogen (TKN) is a measure

of the amount or organic nitrogen in the stream. TKN concentrations did not exceed the

90th percentile screening value (0.4 mg/L) at either VADEQ ambient monitoring station

(Figures 9.13 and 9.14).



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Tot

al o

rgan

ic so

lids (

mg/

L)

.90th percentile screening value = 63 mg/L

Figure 9.11 Total organic solids concentrations at VADEQ monitoring station 6BPLL004.24.

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Tot

al o

rgan

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lids (

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.


Figure 9.12 Total organic solids concentrations at VADEQ monitoring station 6BPLL006.38.



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Tot

al K

jeld

ahl n

itrog

en (m

g/L

) .


Figure 9.13 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPLL004.24.

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Tot

al K

jeld

ahl n

itrog

en (m

g/L

) .


Figure 9.14 Total kjeldahl nitrogen concentrations at VADEQ monitoring station 6BPLL006.38.



The assemblage for all of the benthic stations on the South Fork Powell River from the

VADEQ Ecological Data Application System (EDAS) database were examined, and

Hydropsychidae (netspinning caddisflies) were found not to be the most dominant or a

very significant family at each monitoring station. The average contribution was 10%

and the range was 7% - 13%. Hydropsychidae are often associated with high

concentrations of organic matter in streams. This corresponds very well with the

chemical data presented above and confirms that organic matter is not a stressor in the

South Fork Powell River.

9.2.8 Sulfate

Sulfate concentrations did not exceed the 90th percentile screening value (76 mg/L) at

VADEQ monitoring station 6BPLL006.38 (Figure 9.15) (Sulfate samples were not

collected at VADEQ ambient monitoring station 6BPLL004.24). Sulfate is considered a

non-stressor in the South Fork Powell River.

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Sulfa

te (m

g/L

) .


Figure 9.15 Sulfate concentrations at VADEQ monitoring station 6BPLL006.38.



9.2.9 Conductivity/total dissolved solids (TDS)

Conductivity measurements did not exceed the 90th percentile screening value at either of

the two VADEQ ambient water quality monitoring stations (Figures 9.16 and 9.17). In

addition no TDS concentrations exceeded the 90th percentile screening value at either

VADEQ ambient water quality monitoring station (Figures 9.18 and 9.19).

0

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450

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05/0

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Con

duct

ivity

(μm

hos/

cm)

.


Figure 9.16 Conductivity measurements at VADEQ monitoring station 6BPLL004.24.



0

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450

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Con

duct

ivity

(μm

hos/

cm)

.

90th percentile screening value = 402 ℵmhos/cm

Figure 9.17 Conductivity measurements at VADEQ monitoring station 6BPLL004.24.

0

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Tot

al d

isso

lved

solid

s (m

g/L

) .


Figure 9.18 Total dissolved solids concentrations at VADEQ monitoring station 6BPLL004.24.



0

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250

300

08/9

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Tot

al d

isso

lved

solid

s (m

g/L

) .


Figure 9.19 Total dissolved solids concentrations at VADEQ monitoring station 6BPLL006.38.


There are no possible stressors in the South Fork Powell River.

9.4 Most Probable Stressor(s)

Probable stressor(s) in the South Fork Powell River are reported in Table 9.2.

Table 9.2 Probable stressors in the South ForkPowell River. Parameter Location in Document

Sediment 9.4.1

9.4.1 Sediment

Total suspended solids concentrations were low at VADEQ monitoring stations

6BPLL004.24 and 6BPLL006.38 (Figures 9.20 and 9.21).



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Figure 9.20 Total suspended solids concentrations at VADEQ monitoring station 6BPLL004.24.

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Habitat scores at 6BPLL002.55 and 6BPLL001.61 indicate an occasional problem with

sediment (see Table 6. 23 for the ranges of habitat scores, scores below 11 are considered

unacceptable). The Embeddedness and Pool Sediment habitat metric scores below 11 are

shown in Table 9.3. Both the Embeddedness and Pool Sediment habitat metrics were in

the acceptable range at VADEQ benthic monitoring stations 6BPLL004.49 and

6BPLL006.38 (Tables 6.40 and 6.41).

Table 9.3 Summary of low Embeddedness and Pool Sediment scores at VADEQ benthic monitoring stations on the South Fork Powell River.

Habitat Metric 6BPLL002.55

Nov-97 6BPLL002.55

Sep-07 6BPLL001.61

Mar-08 6BPLL001.61

Oct-08 Embeddedness 9 OK OK 8 Pool Sediment 8 7 10 7 OK – score was satisfactory. Based on the occasionally low Embeddedness and Pool Sediment habitat scores,

sediment is considered a probable stressor in the South Fork Powell River. The modeling

and subsequent allocations for the S.F. Powell River will be based on total suspended

solids (TSS).


REFERENCE WATERSHED SELECTION 10-1

10. REFERENCE WATERSHED SELECTION

A reference watershed approach was used to estimate the necessary load reductions that

are needed to restore a healthy aquatic community and allow the Powell River watershed

to achieve the designated uses. This approach is based on selecting a non-impaired

watershed that has similar land use, soils, watershed characteristics, area (not to exceed

double or not to be less than half the size of the impaired watershed), and located in or

near the same ecoregion as the impaired watershed.

The modeling process uses load rates or pollutant concentrations in the non-impaired

watershed as a target for load reductions in the impaired watershed. The impaired

watershed is modeled to determine the current load rates and establish what reductions

are necessary to meet the load rates of the non-impaired watershed.

The Powell River at the most downstream impaired benthic monitoring station

(6BPOW120.12) is a sixth order stream. The choices of a suitable fifth or sixth order

reference stream, with mining impacts and in a similar ecoregion were very limited. The

most logical choice was the Clinch River from river mile 265.10 (near Tunnel Hill). The

Clinch River has mining impacts in addition to being in the same ecorgeion. It is also a

sixth order stream at Tunnel Hill and the benthic monitoring station (6BCLN265.10) is

not impaired. Like the Powell River, the Clinch River is also home to a number of

endangered mussel species. Table 10.1 shows the land use comparison between the

Powell and Clinch Rivers. Figure 10.1 shows the respective locations of the two

watersheds.


10-2 REFERENCE WATERSHED SELECTIONS

Figure 10.1 Location of the impaired and reference watersheds.


REFERENCE WATERSHED SELECTIONS 10-3

Table 10.1 Powell and Clinch Rivers land use comparison.

Land use Clinch River (Reference)

Powell River(Impaired)

Active Mining 1,197 9,994 AML 4,757 14,865 Barren 1,060 2,930

Commercial 4,297 1,883 Cropland 1,207 294

Forest 223,762 188,751 Pasture 106,725 53,711

Residential 23,580 20,095 Water 3,943 378

Total Acres 370,528 292,901 AML – Abandoned mine land.


SEDIMENT MODELING PROCEDURE 11-1

11. MODELING PROCEDURE: LINKING THE SOURCES TO THE ENDPOINT- SEDIMENT

11.1 Modeling Framework Selection - GWLF

A reference watershed approach was used in this study to develop a benthic TMDL for

sediment for the Powell River and Tributaries. As noted in Chapters 7, 8, and 9,

sediment was identified as a probable stressor for these streams. A watershed model was

used to simulate sediment loads from potential sources in this watershed and in the

reference watershed. The model used in this study was the Visual BasicTM version of the

Generalized Watershed Loading Functions (GWLF) model with modifications for use

with ArcView (Evans et al., 2001). The GWLF model was developed at Cornell

University (Haith and Shoemaker, 1987; Haith, et al., 1992) for use in ungaged

watersheds. The model also included modifications made by Yagow et al., (2002) and

BSE, (2003). Numeric endpoints were based on unit-area loading rates calculated for the

reference watershed. The TMDL was then developed for the impaired watershed based

on these endpoints and the results from load allocation scenarios. Parameters are

described in the Glossary.

GWLF is a continuous simulation, spatially lumped model that operates on a daily time

step for water balance calculations and monthly calculations for sediment and nutrients

from daily water balance. In addition to runoff and sediment, the model simulates

dissolved and attached nitrogen and phosphorus loads delivered to streams from

watersheds with both point and nonpoint sources of pollution. The model considers flow

input from both surface and groundwater. Land use classes are used as the basic unit for

representing variable source areas. The calculation of nutrient loads from septic systems,

stream-bank erosion from livestock access, and the inclusion of sediment and nutrient

loads from point sources are also supported. Runoff is simulated based on the Soil

Conservation Service's Curve Number method (SCS, 1986). Erosion is calculated from a

modification of the Universal Soil Loss Equation (USLE) (Schwab et al., 1981;

Wischmeier and Smith, 1978). Sediment estimates use a delivery ratio based on a


11-2 SEDIMENT MODELING PROCEDURE

function of watershed area and erosion estimates from the modified USLE. The sediment

transported depends on the transport capacity of runoff.

For execution GWLF uses three input files for weather, transport, and nutrient loads. The

weather file contains daily temperature and precipitation for the period of record. Data

was based on a water year starting in October and ending in September. The transport

file contains input data related to hydrology and sediment transport. The nutrient file

contains nutrient values for the various land uses, point sources, and septic system types,

and also urban sediment buildup rates.

11.2 GWLF Model Setup

Watershed data needed to run GWLF used in this study were generated using GIS spatial

coverage, local weather data, streamflow data, literature values, and other data.

Subwatersheds are not required to run the GWLF model. For the sediment TMDL

development, the total area for the reference watershed was equated to the area of

impaired watershed. To accomplish this, the area of land use categories in reference

watershed was proportionately decreased based on the percentage land use distribution.

As a result, the watershed area for reference river was decreased to be equal to the

watershed area of the impaired watershed.

The GWLF model was developed to simulate runoff, sediment and nutrients in ungaged

watersheds based on landscape conditions such as land use/land cover, topography, and

soils. In essence, the model uses a form of the hydrologic units (HU) concept to estimate

runoff and sediment from different pervious areas (HUs) in the watershed (Li, 1975;

England, 1970). In the GWLF model, the nonpoint source load calculation for sediment

is affected by land use activity (e.g., farming practices), topographic parameters, soil

characteristics, soil cover conditions, stream channel conditions, livestock access, and

weather. The model uses land use categories as the mechanism for defining homogeneity

of source areas. This is a variation of the HU concept, where homogeneity in hydrologic

response or nonpoint source pollutant response would typically involve the identification

of soil land use topographic conditions that would be expected to give a homogeneous

response to a given rainfall input. A number of parameters are included in the model to



index the effect of varying soil-topographic conditions by land use entities. A description

of model parameters is given in the Glossary and a description of how parameters and

other data were calculated and/or assembled is below.

11.2.1 Sediment Source Assessment

Three source areas were identified as the primary contributors to sediment loading in

Powell River and Tributaries that are the focus of this study – surface runoff, point

sources, and streambank erosion. The sediment process is a continual process but is often

accelerated by human activity. An objective of the TMDL process is to minimize the

acceleration process. This section describes predominant sediment source areas, model

parameters, and input data needed to simulate sediment loads.

11.2.1.1 Surface Runoff

During runoff events (natural rainfall or irrigation), sediment is transported to streams

from pervious land areas (e.g., agricultural fields, lawns, forest.). Rainfall energy, soil

cover, soil characteristics, topography, and land management affect the magnitude of

sediment loading. Agricultural management activities such as overgrazing (particularly

on steep slopes), high tillage operations, livestock concentrations (e.g., along stream

edge, uncontrolled access to streams), forest harvesting, and land disturbance due to

mining and construction (roads, buildings, etc.) all tend to accelerate erosion at varying

degrees. During dry periods, sediment from air or traffic builds up on impervious areas

and is transported to streams during runoff events. The magnitude of sediment loading

from this source is affected by various factors (e.g., the deposition from wind erosion and

vehicular traffic).

11.2.1.2 Channel and Streambank Erosion

An increase in impervious land without appropriate stormwater control increases runoff

volume and peaks, which leads to greater channel erosion potential. It has been well

documented that livestock with access to streams can significantly alter physical

dimensions of streams through trampling and shearing (Armour et al., 1991; Clary and

Webster, 1989; Kaufman and Kruger, 1984). Increasing the bank full width decreases

stream depth, increases sediment, and adversely affects aquatic habitat (USDI, 1998).



Management practices that allow mowing, paving, building or material storage up to the

edge of a stream or bank cause instability also. These practices do not allow natural

stream migration along the floodplain and allow room for flood waters to dissipate. This

makes banks and stream segments unstable and erosion from banks more prominent.

11.2.1.3 TSS Point Sources

Sediment loads from permitted wastewater, industrial, and construction stormwater

dischargers, and mining operations are included in the WLA component of the TMDL, in

compliance with 40 CFR§130.2(h). Fine sediments are included in TSS loads that are

permitted for various facilities, industrial and construction stormwater, and VPDES

permits within the Powell River and Tributaries watershed.

The TSS loading from uncontrolled discharges (straight pipes) was accounted for in the

sediment TMDL. A TSS concentration from human waste was estimated as 320 mg/L

(Lloyd, 2004) at 75 gal of waste water per day per person.

11.2.2 Sediment Source Representation – Input Requirements

As described in Section 11.2, the GWLF model was developed to simulate runoff,

sediment and nutrients in ungaged watersheds based on landscape conditions such as land

use/land cover, topography, and soils. The following sections describe required inputs

for the GWLF program.

11.2.2.1 Streamflow and Weather data

Daily precipitation data was available within the Powell River and Tributaries watershed

at the Big Stone Gap NCDC Coop station #440735. Missing temperature and

precipitation data were filled with values from the Pennington Gap NCDC Coop station

#446626.

Daily precipitation data was available within the Clinch River watershed at the Richlands

NCDC Coop station #447174. Missing temperature and precipitation data were filled

with values from the Lebanon NCDC Coop station # 444777.



11.2.2.2 Land use and Land cover

Land use distributions for the Powell River and Tributaries, and for the area-adjusted

Clinch River watershed are given in Table 11.1. Land use acreage for the reference

watersheds were adjusted down by the ratio of impaired watershed to reference watershed

maintaining the original land use distribution. These areas were used for modeling

sediment. The values in Table 11.1 for the Powell River and Tributaries do not include

the Straight Creek and Callahan Creek drainage areas.

Table 11.1 Land use areas used in the GWLF model for the Powell River and Tributaries and area-adjusted Clinch River watersheds.

Sediment Source Powell River – Straight Creek – Callahan Creek

Area Adjusted Clinch River

(ha)1 (ha) Pervious Area:

AML 4160.0 1332.6 Water 149.6 1104.6 Barren 1051.9 296.8

Active Mine 3302.9 335.2 Row Crop – Low Tillage 15.5 44.0 Row Crop – High Tillage 103.4 288.3

Forest 62833.8 58043.1 Disturbed Forest 2618.1 4636.0

Commercial 338.7 578.9 Residential 3533.9 3176.7

Hay 5370.3 5632.9 Unimproved Pasture 7733.2 11680.3

Improved Pasture 8377.7 12582.0 Impervious Area:


Watershed Total 103,784.4 103,784.4 1 1ha = 2.47 ac

11.2.2.3 Sediment Parameters

Sediment parameters include USLE parameters erodibility factor (K), length of slope

(LS), cover crop factor (C), and practice factor (P), sediment delivery ratio, and a buildup

and loss functions for impervious surfaces. The product of the USLE parameters,

KLSCP, is entered as input to GWLF. Soils data for the watersheds were obtained from



the Soil Survey Geographic (SSURGO) database for Virginia (SCS, 2004). The K factor

relates to a soil's inherent erodibility and affects the amount of soil erosion from a given

field. The area-weighted K-factor by land use category was calculated using GIS

procedures. Land slope was calculated from USGS National Elevation Dataset data

using GIS techniques. The length of slope was based on VirGIS procedures given in

VirGIS Interim Reports (e.g., Shanholtz et al., 1988). The area-weighted LS factor was

calculated for each land use category using procedures recommended by Wischmeier and

Smith (1978). The weighted C-factor for each land use category was estimated following

guidelines given in Wischmeier and Smith, 1978, GWLF User’s Manual (Haith et al.,

1992) and Kleene, 1995. The practice factor (P) was set at 1.0 for all land.

11.2.2.4 Sediment Delivery Ratio

The sediment delivery ratio specifies the percentage of eroded sediment delivered to

surface water and is empirically based on watershed size. The sediment delivery ratios

for impaired and reference watersheds were calculated as an inverse function of

watershed size (Evans et al., 2001). The value used for the Powell River and Clinch

River watersheds was 0.057.

11.2.2.5 SCS Runoff Curve Number

The runoff curve number is a function of soil type, antecedent moisture conditions, and

cover and management practices. The runoff potential of a specific soil type is indexed

by the Soil Hydrologic Group (SHG) code. Each soil-mapping unit is assigned SHG

codes that range in increasing runoff potential from A to D. The SHG code was given a

numerical value of 1 to 4 to index SHG codes A to D, respectively. An area-weighted

average SHG code was calculated for each land use/land cover from soil survey data

using GIS techniques. Runoff curve numbers (CN) for SHG codes A to D were assigned

to each land use/land cover condition for antecedent moisture condition II following

GWLF guidance documents and SCS, 1986 recommended procedures. The runoff CN

for each land use/land cover condition then was adjusted based on the numeric area-

weighted SHG codes.



11.2.2.6 Parameters for Channel and Streambank Erosion

Parameters for streambank erosion include animal density, total length of streams with

livestock access, total length of natural stream channel, fraction of developed land, mean

stream depth, and watershed area. The animal density was calculated by dividing the

number of animal units (beef and dairy) by watershed area in acres. The total length of

the natural stream channel was estimated from USGS NHD hydrography coverage using

GIS techniques. The mean stream depth was estimated as a function of watershed area.

11.2.2.7 Evapo-transpiration Cover Coefficients

Evapotranspiration (ET) cover coefficients were entered by month. Monthly ET cover

coefficients were assigned each land use/land cover condition following procedures

outlined in Novotny and Chesters (1981) and GWLF guidance. Area-weighted ET cover

coefficients were then calculated for each sediment source class. These values were then

adjusted during hydrology calibration.

11.2.2.8 TSS Permitted and Direct Sources

Construction stormwater permitted loads were calculated as the average annual modeled

runoff times the area governed by the permit times a maximum TSS concentration of 100

mg/l. The modeled runoff for the construction stormwater discharge was estimated as

equal to the annual runoff from the barren area. The modeled runoff for the industrial

stormwater discharge was estimated as equal to the annual runoff from the developed

area. For the construction and industrial permits, the average annual runoff (cm/yr) was

multiplied by the permit area (ha), multiplied by the permitted TSS concentration (100

mg/L), and were multiplied by conversion factors to get a permit load in metric tons per

year (t/yr).

For the domestic wastewater treatment, and VPDES permits, the design discharge was

multiplied by the permitted TSS concentration of 100 mg/L and then multiplied by

conversion factors to get a permit load in metric tons per year (t/yr). Carwash load was

estimated in a similar way using a TSS concentration of 60 mg/L. Each of the domestic

wastewater treatment (DWT) permits was calculated separately as noted.



The existing annual load for active mining areas was calculated by multiplying the

average annual runoff volume from active mining lands in permitted areas by the runoff-

weighted TSS concentration from the active mining areas. All permitted loads are shown

in Tables 11.2.



Table 11.2 Permitted Sources in the Powell River watershed excluding the Straight Creek and Callahan Creek areas.

Permit Number Permit Type Sediment (t/yr)

VAG750004 Car Wash 0.41 VAG750024 Car Wash 0.41 VA0020940 VPDES 82.95 VA0029599 VPDES 24.88 VA0052311 VPDES 2.03 VA0052337 VPDES 2.03 VA0053023 VPDES 5.60 VA0060798 VPDES 0.50 VA0063941 VPDES 0.20 VA0070751 VPDES 14.10 VA0075515 VPDES 1.24 VA0089397 VPDES 33.18 VAG110005 Mixed Concrete 0.14 VAG110210 Mixed Concrete 0.14 VAR050060 Industrial 0.14 VAR050065 Industrial 0.14 VAR050067 Industrial 0.14 VAR050131 Industrial 0.14 VAR050157 Industrial 0.14 VAR051276 Industrial 0.14 VAR051779 Industrial 0.14 VAG840005 Mining 0.14 VAG840005 Mining 0.14 VAG840005 Mining 0.14 VAG840015 Mining 0.14 VAR103405 Construction 0.325 VAR101845 Construction 0.327 VAR101845 Construction 0.327 VAR101845 Construction 0.327 VAR101845 Construction 0.327 VAR104287 Construction 0.324 VAR104305 Construction 0.324 VAR104475 Construction 0.327 VAR102769 Construction 0.327 VAR104500 Construction 0.324 VAR104502 Construction 0.324



11.2.3 Selection of Representative Modeling Period - GWLF

An analysis of historic precipitation and streamflow in Powell River was preformed to

select a representative time frame. The time period chosen was water year 1993 through

water year 1996.

11.3 GWLF Sensitivity Analyses

Sensitivity analyses were conducted to assess the sensitivity of the model to changes in

hydrologic and water quality parameters as well as to assess the impact of unknown

variability in source allocation (e.g., seasonal and spatial variability of land disturbance,

runoff curve number, etc.). Sensitivity analyses were run on the runoff curve number

(CN), the combined erosion factor (KLSCP) that combines the effects of soil erodibility,

land slope, land cover, and management practices, the recession coefficient, the seepage

coefficient, the unsaturated available water capacity (AWC), and the Evapotranspiration

(ET) Coefficient (Table 11.3).



Table 11.3 Base parameter values used in GWLF sensitivity analysis.

Land use CN KLSCP Recession Coefficient (1/d)

Seepage Coefficient

(1/d)

Unsaturated Available

Water Capacity (AWC)

Evapotrans-piration (ET)

Coefficient

Entire Watershed 0.07 0.035 10.1 0.15 - 0.88 Pervious Area:

AML 73.9 0.536003 Water 98.0 0.000000 Barren 84.7 0.619403

Active Mine 86.4 0.824396 Row Crop – Low

Tillage 75.6 0.126053

Row Crop – High Tillage 79.2 0.286263

Forest 64.0 0.003430 Disturbed Forest 72.6 0.200216


Hay 63.7 0.004352 Unimproved Pasture 73.4 0.081602

Improved Pasture 66.7 0.014144 Impervious Area:


For a given simulation, the model parameters in Table 11.3 were set at the base value

except for the parameter being evaluated. The parameters were adjusted individually to -

10% and +10% of the base value and then the output values from the base run and the

adjusted run were compared. The results in Table 11.4 show that the parameters are

directly correlated with runoff volume and sediment load. The relationships show fairly

linear responses, with outputs being more sensitive to changes in CN than KLSCP. The

hydrology model was most sensitive to changes in curve number values and

evapotranspiration (ET) coefficient values. The sediment loading model was most

sensitive to changes in curve number values and KLSCP values. The results tend to

reiterate the need to carefully evaluate conditions in the watershed and follow a

systematic protocol in establishing values for model parameters.



Table 11.4 Sensitivity of GWLF model response to changes in selected parameters for Powell River.

Model Parameter Parameter Change (%)

Total Runoff Volume Percent Change (%)

Total Sediment Load Percent Change (%)

CN 10 -3.0% -11.4% CN -10 3.6% 9.7%

KLSCP 10 0.0% -7.0% KLSCP -10 0.0% 7.0%

Recession Coefficient 10 -2.8% -0.1% Recession Coefficient -10 2.5% 0.1% Seepage Coefficient 10 2.7% 0.1% Seepage Coefficient -10 -2.6% -0.1%

ET Coefficient 10 3.9% 0.2% ET Coefficient -10 -4.0% -0.2%

Unsaturated AWC 10 0.3% 0.0% Unsaturated AWC -10 -0.3% 0.0%

11.4 GWLF Hydrology Calibration

Although the GWLF model was originally developed for use in ungaged watersheds,

calibration was performed to ensure that hydrology was being simulated accurately. This

process was performed in order to minimize errors in sediment simulations due to

potential gross errors in hydrology. The model’s parameters were assigned based on

available soils, land use, and topographic data. Parameters that were adjusted during

calibration included the recession constant, the monthly evapotranspiration cover

coefficients, the unsaturated soil moisture storage, and the seepage coefficient.

11.4.1 Powell River – Impaired Stream

The final GWLF calibration results for Powell River are displayed in Figures 11.1 and

11.2 for the calibration period with statistics showing the accuracy of fit given in the

Table 11.5. Model calibrations were considered good for total runoff volume (Table

11.5). Monthly fluctuations were variable but were still reasonable considering the

general simplicity of GWLF.

Table 11.5 GWLF flow calibration statistics for Powell River.

Watershed Simulation Period R2Correlation value Total Volume Error (Sim-Obs)

Powell River 10/1/1992 – 9/30/1996 0.9129 0.59%

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Figure 11.1 Comparison of monthly GWLF simulated (Modeled) and monthly USGS (Observed) streamflow in Powell River.

SED

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Figure 11.2 Comparison of cumulative monthly GWLF simulated (Modeled) and cumulative USGS (Observed) streamflow in Powell River.

TMDL Development Chapter 10 Excerpts DRAFTPowell River and Tributaries, VA


11.4.2 Clinch River – Reference Stream

The final GWLF calibration results for Clinch River are displayed in Figures 11.3 and

11.4 for the calibration period with statistics showing the accuracy of fit given in the

Table 11.6. Model calibrations were considered good for total runoff volume (Table

11.6). Monthly fluctuations were variable but were still reasonable considering the

general simplicity of GWLF.

Table 11.6 GWLF flow calibration statistics for Clinch River.

Watershed Simulation Period R2Correlation value Total Volume Error (Sim-Obs)

Clinch River 10/1/1992 – 9/30/1996 0.926 -1.73%

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Figure 11.3 Comparison of monthly GWLF simulated (Modeled) and monthly USGS (Observed) streamflow in Clinch River.

SEDIM

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Figure 11.4 Comparison of cumulative monthly GWLF simulated (Modeled) and cumulative USGS (Observed) streamflow in Clinch River.



11.5 Sediment Existing Conditions

A list of parameters from the GWLF transport input files that were finalized for existing

conditions are given in Table 11.7. Monthly evaporation cover coefficients are listed in

Table 11.8.

Table 11.7 GWLF watershed parameters in the calibrated impaired and reference watersheds.

GWLF Watershed Parameter Units Powell River Clinch River Recession Coefficient Day-1 0.07 0.09 Seepage Coefficient Day-1 0.035 0.026

Sediment Delivery Ratio --- 0.057 0.057 Unsaturated Water Capacity (cm) 10.1 11.7

Rainfall Erosivity Coefficient (Apr-Sep) --- 0.28 0.28

Rainfall Erosivity Coefficient (Oct-Mar) --- 0.10 0.10

% Developed land (%) 0.044 0.056 Livestock density (AU/ac) 0.035 0.04

Area-weighted soil erodibility (K) --- 0.23 0.22 Area-weighted Curve Number --- 68.0 68.1

Total Stream Length (m) 866,555 1,175,712 Mean channel depth (m) 1.5 1.7

Table 11.8 Calibrated GWLF monthly evaporation cover coefficients. Watershed Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar

Powell River 0.15 0.3 0.88 0.88 0.88 0.88 0.88 0.88 0.15 0.15 0.15 0.15

Clinch River 0.15 0.3 0.88 0.88 0.88 0.88 0.88 0.98 0.88 0.15 0.15 0.15



Table 11.9 lists the area-weighted USLE erosion parameter (KLSCP) and runoff curve

number by land use for each watershed. The curve number values are area weighted by

land use for all subwatersheds.

Table 11.9 The GWLF curve numbers and KLSCP values for existing conditions in the Powell River and Clinch River watersheds.

Powell River Clinch River Sediment Source CN KLSCP CN KLSCP

Pervious Area: AML 73.9 0.536003 74.1 0.516679Water 98.0 0.000000 98.0 0.000000Barren 84.7 0.619403 84.6 0.710841

Active Mine 86.4 0.824396 86.6 0.487355Row Crop – Low Tillage 75.6 0.126053 76.3 0.140526Row Crop – High Tillage 79.2 0.286263 79.6 0.319131

Forest 64.0 0.003430 62.0 0.004390Disturbed Forest 72.6 0.200216 71.1 0.256248

Commercial 65.8 0.006370 65.9 0.005486Residential 66.8 0.020504 66.4 0.022724

Hay 63.7 0.004352 62.1 0.006325Unimproved Pasture 73.4 0.081602 72.2 0.118598

Improved Pasture 66.7 0.014144 65.1 0.020557Impervious Area:

Commercial 98.0 0.006370 98.0 0.005486Residential 98.0 0.020504 98.0 0.022724



The sediment loads were modeled for existing conditions in Powell River and the

reference watershed, Clinch River. The existing condition is the combined sediment

load, which compares to the area-adjusted reference watershed load (Table 11.10).

Table 11.10 Existing sediment loads for Powell River and area-adjusted Clinch River watersheds. Reference Watershed

Sediment Source Powell River Area-Adjusted Clinch River t/yr t/ha/yr t/yr t/ha/yr

Pervious Area: AML 5,896.4 1.4 1,611.7 1.2 Barren 15,105.2 14.4 4,281.5 14.4

Row Crop – Low Tillage 36.6 2.4 112.9 2.6 Row Crop – High Tillage 617.8 6.0 1,700.1 5.9

Forest 3,061.2 0.0 3,170.1 0.1 Disturbed Forest 2,714.3 1.0 5,279.7 1.1

Commercial 31.2 0.1 40.6 0.1 Residential 1,059.2 0.3 932.8 0.3

Hay 331.9 0.1 443.2 0.1 Unimproved Pasture 10,996.4 1.4 21,141.2 1.8

Improved Pasture 1,732.1 0.2 3,247.3 0.3 Impervious Area:

Commercial 91.2 0.2 155.2 0.2 Residential 285.3 0.1 255.5 0.1

Direct Sources: Streambank Erosion 11,508.1 20,320.8

Straight Pipes 31.3 62.5 Permitted Sources:

DEQ - VPDES 179.0 1085.6 DMME - Mining 502.3 86.5

Straight Creek Existing Load 18,792.0 N/A Callahan Creek Existing Load 18,664.0 N/A

Watershed Total 91,635.5 63,927.4


SEDIMENT ALLOCATION 12-1

12. SEDIMENT ALLOCATION

Total Maximum Daily Loads consist of waste load allocations (WLAs, permitted point

sources) and load allocations (LAs, nonpermitted sources), including natural background

levels. Additionally, the TMDL must include a margin of safety (MOS) that either

implicitly or explicitly accounts for uncertainties in the process. The definition is

typically denoted by the expression:

TMDL = WLAs + LAs + MOS

The TMDL becomes the amount of a pollutant that can be assimilated by the receiving

water body and still achieve water quality standards. For sediment, the TMDL is

expressed in terms of annual load in metric tons per year (t/yr).

The Powell River sediment TMDL was developed using using the Clinch River as a

reference watershed. The models were run over the period of 10/1/1993 to 9/30/1996 for

modeling sediment allocations. The target sediment TMDL load for Powell River is the

average annual load in metric tons per year (t/yr) from the area-adjusted Clinch River

watershed under existing conditions minus a Margin of Safety (MOS).

12.1 Margin of Safety

In order to account for uncertainty in modeled output, an MOS was incorporated into the

TMDL development process. Individual errors in model inputs, such as data used for

developing model parameters or data used for calibration, may affect the load allocations

in a positive or a negative way. For example, the typical method of assessing water

quality through monitoring involves the collection and analysis of grab samples. The

results of water quality analyses on grab samples collected from the stream may or may

not reflect the “average” condition in the stream at the time of sampling. Calibration to

observed data derived from grab samples introduces modeling uncertainty.

An MOS can be incorporated implicitly in the model through the use of conservative

estimates of model parameters, or explicitly as an additional load reduction requirement.

The MOS for the sediment TMDLs was explicitly expressed as 10% of the area-adjusted

reference watershed load.


12-2 SEDIMENT ALLOCATION

12.2 Future Growth Considerations

The land use in the Powell River watershed is not expected to change significantly in the

next 25 years. The Powell River watershed is mostly rural with the exception of Big

Stone Gap, Penninton Gap, and Appalachia which are small town considering the large

watershed size. It is assumed that residential and commercial growth in the watershed

will not have considerable impact on future sediment loads. However, increased mining

operations could have an impact if sediment control ponds exceed the permitted 70 mg/L.

A sediment load value for future growth was determined as 1% of the total TMDL to

account for urbanization and/or increased mining activities. This was incorporated into

the WLA for use as current discharges expand and for future permits that may discharge

sediment.

12.3 Sediment TMDL

The target TMDL load for Powell River is the average annual load in metric tons per year

(t/yr) from the area-adjusted Clinch River watershed under existing conditions. To reach

the TMDL target load, three different scenarios were run (Table 12.1). Sediment loads

from straight pipes were reduced 100% in all scenarios due to health implications and the

requirements of the fecal bacteria TMDL. Scenario 1 shows similar reductions to

sediment loads from row crop, pasture, residential, disturbed forest, abandoned mine

land, barren, and streambank erosion. Scenario 2 shows reductions to loads from mining

related and disturbed forest land uses. Scenario 3 shows reductions to loads from mining

related and agricultural activities in addition to streambank erosion. All three scenarios

meet the TMDL goal at a total sediment load reduction of 37.21%. Scenario 1 was

chosen to use for the final TMDL because it has reasonable reductions on all types of

land uses.

The difference between the existing and allocated load for the DMME mining permits is

a result of the different way of estimating these loads. While the TSS concentration was

estimated as the flow-weighted concentration from mining lands during existing stage,

the allocated TSS concentration was assumed to be the permitted concentration of 70

mg/L.



Table 12.1 Final TMDL allocation scenario for the impaired Powell River watershed.

Sediment Source Existing Powell Loads

Scenario 1 Reductions

(Final)

Scenario 1 Allocated

Loads



Loads



Loads

t/yr (%) t/yr (%) t/yr (%) t/yr Pervious Area:

AML 5,896.35 23.35 4,519.85 47.15 3,116.40 35.24 3,818.71Barren 15,105.23 23.35 11,578.91 47.15 7,983.57 0 15,105.23

Row Crop – Low Tillage 36.63 0 36.63 0 36.63 0 36.63

Row Crop – High Tillage 617.79 23.35 473.57 0 617.79 35.24 400.11 Forest 3,061.24 0 3,061.24 0 3,061.24 0 3,061.24

Disturbed Forest 2,714.29 23.35 2,080.64 47.15 1,434.58 35.24 1,757.88Commercial 31.16 0 31.16 0 31.16 0 31.16 Residential 1,059.15 23.35 811.89 0 1,059.15 0 1,059.15

Hay 331.95 0 331.95 0 331.95 0 331.95 Unimproved Pature 10,996.41 23.35 8,429.30 0 10,996.41 35.24 7,121.71Improved Pasture 1,732.11 0 1,732.11 0 1,732.11 0 1,732.11

Impervious Area: comm_imp 91.17 0 91.17 0 91.17 0 91.17

res_imp 285.32 0 285.32 0 285.32 0 285.32 Direct Sources:

Streambank Erosion 11,508.08 23.35 8,821.52 0 11,508.08 35.24 7,453.09Straight Pipes 31.33 100 0.00 100 0.00 100 0.00

Permitted Sources: DEQ VPDES permits 178.99 0 178.99 0 178.99 0 178.99

DMME Mining Permits 502.30 0 845.18 0 845.18 0 845.18 Straight Creek Existing Load1 18,792.00 64.58 6,656.00 64.58 6,656.00 64.58 6,656.00Callahan Creek Existing Load1 18,664.00 62.84 6,936.00 62.84 6,936.00 62.84 6,936.00Future Growth 632.94 632.94 632.94

Margin of Safety 6,392.74 6,392.74 6,392.74Watershed Total 91,635.50 63,927.11 63,927.41 63,927.31

1 Existing and allocated loads from Straight Creek and Callahan Creek were taken from the already developed TMDLs for the two creeks since they fall within the current study area. No additional reductions were recommended from the two creeks since the percentage reductions called for in Table 12.1 are the same in the corresponding, previously developed TMDLs.

The active mining permits issued by the Virginia DMME are shown in Table 12.2 with

the existing and allocated loads. These loads were summed and entered into Table 12.1.



Table 12.2 Existing and allocated annual sediment loads for DMME mining permits within the Powell River watershed.

Existing Load

Allocated Load

Existing Load

Allocated Load

DMME Mine

Permits t/yr t/yr

DMME Mine

Permits t/yr t/yr 1100033 24.51 41.25 1301742 0.23 0.38 1100439 5.96 10.03 1301942 0.21 0.36 1100583 4.01 6.75 1301992 0.56 0.94 1100584 0.49 0.83 1402032 1 1.69 1100735 2.27 3.81 1500090 0.74 1.24 1100877 4.6 7.74 1501065 14.36 24.16 1101350 8.9 14.97 1501778 43.35 72.93 1101554 1.82 3.07 1501947 1.79 3.01 1101565 2.09 3.52 1600876 11.11 18.70 1101661 10.77 18.12 1601423 6.05 10.18 1101760 45.21 76.06 1601466 29.89 50.30 1101800 5.37 9.04 1601486 32.17 54.13 1101804 25.03 42.12 1601519 4.4 7.40 1101813 8.76 14.74 1601576 38.38 64.57 1101824 2.6 4.37 1601656 2.31 3.88 1101905 24.3 40.88 1601744 32.11 54.03 1101918 14.64 24.64 1700624 1.05 1.77 1101954 34.98 58.85 1701152 0.31 0.53 1101975 8.94 15.04 1701869 1.46 2.46 1101991 9.43 15.87 1102011 9.8 16.49 1102028 10.72 18.05 1102031 1.75 2.95 1201589 0.41 0.69 1201680 0.1 0.17 1201803 0.37 0.62 1201875 0.58 0.97 1201921 0.41 0.69 1201949 0.73 1.23 1202015 0.19 0.32 1301430 0.29 0.49 1301533 1.64 2.77 1301561 1.41 2.38 1301590 0.55 0.92 1301687 7.19 12.10



The final overall sediment load reduction required for Powell River is 37.21% (Table

12.3).

Table 12.3 Required sediment reductions for Powell River and Tributaries. Reductions Required Load Summary Powell River

(t/yr) (t/yr) (% of existing load) Existing Sediment Load 91,635.5

Final Allocated Load (WLA+LA) 57,534.37 34,101.13 37.21%

The sediment TMDL for Powell River includes three components – WLA, LA, and the

10% MOS. The WLA was calculated as the sum of all permitted point source discharges.

The LA was calculated as the target TMDL load minus the WLA load minus the MOS

(Table 12.4).

Table 12.4 Average annual sediment TMDL for Powell River. Impairment WLA LA MOS TMDL

t/yr t/yr t/yr t/yr Powell River 1,657.11 55,877.26 6,392.74 63,927.11

DEQ VPDES permits: VAG750004 0.41 VAG750024 0.41 VA0020940 82.95 VA0029599 24.88 VA0052311 2.03 VA0052337 2.03 VA0053023 5.60 VA0060798 0.50 VA0063941 0.20 VA0070751 14.10 VA0075515 1.24 VA0089397 33.18 VAG110005 0.14 VAG110210 0.14 VAR050060 0.14 VAR050065 0.14 VAR050067 0.14 VAR050131 0.14 VAR050157 0.14 VAR051276 0.14 VAR051779 0.14 VAG840005 0.14



Impairment WLA LA MOS TMDL t/yr t/yr t/yr t/yr

VAG840005 0.14 VAG840005 0.14 VAG840015 0.14 VAR103405 1.58 VAR101845 0.81 VAR101845 0.81 VAR101845 0.81 VAR101845 0.81 VAR104287 0.80 VAR104305 0.80 VAR104475 0.81 VAR102769 0.81 VAR104500 0.80 VAR104502 0.80

subtotal 178.99 DMME Mining Permits:

1100033 41.25 1100439 10.03 1100583 6.75 1100584 0.83 1100735 3.81 1100877 7.74 1101350 14.97 1101554 3.07 1101565 3.52 1101661 18.12 1101760 76.05 1101800 9.04 1101804 42.12 1101813 14.74 1101824 4.37 1101905 40.88 1101918 24.64 1101954 58.85 1101975 15.04 1101991 15.87 1102011 16.49 1102028 18.05 1102031 2.95 1201589 0.69 1201680 0.17 1201803 0.62



Impairment WLA LA MOS TMDL t/yr t/yr t/yr t/yr

1201875 0.97 1201921 0.69 1201949 1.23 1202015 0.32 1301430 0.49 1301533 2.77 1301561 2.38 1301590 0.92 1301687 12.10 1301742 0.38 1301942 0.36 1301992 0.94 1402032 1.69 1500090 1.24 1501065 24.16 1501778 72.92 1501947 3.01 1600876 18.70 1601423 10.18 1601466 50.30 1601486 54.13 1601519 7.40 1601576 64.57 1601656 3.88 1601744 54.03 1700624 1.77 1701152 0.53 1701869 2.46 subtotal 845.18

Future Growth 632.94

Starting in 2007, the USEPA has mandated that TMDL studies include a maximum

“daily” load (MDL) as well as the average annual load previously shown. The approach

to developing a daily maximum load was similar to the USEPA approved approach found

in the 2007 document titled Options for Expressing Daily Loads in TMDLs (USEPA,

2007). The procedure involved calculating the MDL from the long-term average annual

TMDL load in addition to a coefficient of variation (VC) estimated from the annual load

for 18 years. The annual sediment load ranged from 71,819 t to 162,000 t with a



coefficient of variation (CV) of 0.21. A multiplier was used to estimate the MDL from

the long-term average based on the USEPA guidance. The multiplier estimated for the

Powell River was 1.71. In this case, the long-term average was the annual TMDL

divided by 365.25 days (304.358 t/day) resulting in a MDL of 520.452 t/day. The daily

WLA for individual permits was estimated as the annual WLA divided by 365.25 and

future growth estimated at one percent of the MDL. The daily MOS was estimated as

10% of the MDL. Finally, the daily LA was estimated as the MDL minus the daily MOS

minus the daily WLA. These results are shown in Table 12.5.

Table 12.5 Maximum daily sediment loads (t/day) for Powell River. Impairment WLA LA MOS TMDL

t/day t/day t/day t/day Powell River 8.000 460.407 52.045 520.452

DEQ VPDES permits: VAG750004 0.001 VAG750024 0.001 VA0020940 0.227 VA0029599 0.068 VA0052311 0.006 VA0052337 0.006 VA0053023 0.015 VA0060798 0.001 VA0063941 0.001 VA0070751 0.039 VA0075515 0.003 VA0089397 0.091 VAG110005 < 0.000 VAG110210 < 0.000 VAR050060 < 0.000 VAR050065 < 0.000 VAR050067 < 0.000 VAR050131 < 0.000 VAR050157 < 0.000 VAR051276 < 0.000 VAR051779 < 0.000 VAG840005 < 0.000 VAG840005 < 0.000 VAG840005 < 0.000 VAG840015 < 0.000 VAR103405 0.004 VAR101845 0.002



Impairment WLA LA MOS TMDL t/day t/day t/day t/day

VAR101845 0.002 VAR101845 0.002 VAR101845 0.002 VAR104287 0.002 VAR104305 0.002 VAR104475 0.002 VAR102769 0.002 VAR104500 0.002 VAR104502 0.002

subtotal 0.483 DMME Mining Permits:

1100033 0.113 1100439 0.027 1100583 0.018 1100584 0.002 1100735 0.010 1100877 0.021 1101350 0.041 1101554 0.008 1101565 0.010 1101661 0.050 1101760 0.208 1101800 0.025 1101804 0.115 1101813 0.040 1101824 0.012 1101905 0.112 1101918 0.067 1101954 0.161 1101975 0.041 1101991 0.043 1102011 0.045 1102028 0.049 1102031 0.008 1201589 0.002 1201680 < 0.000 1201803 0.002 1201875 0.003 1201921 0.002 1201949 0.003 1202015 0.001 1301430 0.001



Impairment WLA LA MOS TMDL t/day t/day t/day t/day

1301533 0.008 1301561 0.007 1301590 0.003 1301687 0.033 1301742 0.001 1301942 0.001 1301992 0.003 1402032 0.005 1500090 0.003 1501065 0.066 1501778 0.200 1501947 0.008 1600876 0.051 1601423 0.028 1601466 0.138 1601486 0.148 1601519 0.020 1601576 0.177 1601656 0.011 1601744 0.148 1700624 0.005 1701152 0.001 1701869 0.007 subtotal 2.312

Future Growth 5.205


TMDL IMPLEMENTATION AND REASONABLE ASSURANCE 13-1

13. TMDL REASONABLE ASSURANCE

Once a TMDL has been approved by EPA, measures must be taken to reduce pollution

levels from both point and nonpoint sources. EPA requires that there is reasonable

assurance that TMDLs can be implemented. TMDLs represent an attempt to quantify the

pollutant load that might be present in a waterbody and still ensure attainment and

maintenance of water quality standards. The Commonwealth intends to use existing

programs in order to attain water quality goals. Available programmatic options include

a combination of regulatory authorities, such as the NPDES and Toxics Substances

Control Act (TSCA), as well as state programs including the Toxics Contamination

Source Assessment Policy, and the Virginia Environmental Emergency Response Fund

(VEERF).

The following sections outline the framework used in Virginia to provide reasonable

assurance that the required pollutant reductions can be achieved.

13.1 Continuing Planning Process and Water Quality Management

Planning

As part of the Continuing Planning Process, VADEQ staff will present both EPA-

approved TMDLs and TMDL implementation plans to the State Water Control Board

(SWCB) for inclusion in the appropriate Water Quality Management Plan (WQMP), in

accordance with the Clean Water Act’s Section 303(e) and Virginia’s Public Participation

Guidelines for Water Quality Management Planning.

VADEQ staff will also request that the SWCB adopt TMDL WLAs as part of the Water

Quality Management Planning Regulation (9VAC 25-720), except in those cases when

permit limitations are equivalent to numeric criteria contained in the Virginia Water

Quality Standards. This regulatory action is in accordance with §2.2-4006A.4.c and

§2.2-4006B of the Code of Virginia. SWCB actions relating to water quality

management planning are described in the public participation guidelines referenced

above and can be found on the VADEQ web site under

www.deq.state.va.us/export/sites/default/tmdl/pdf/ppp.pdf.


13-2 TMDL IMPLEMENTATION AND REASONABLE ASSURANCE

13.2 Staged Implementation

In general, Virginia intends for the required control actions, including Best Management

Practices (BMPs), to be implemented in an iterative process that first addresses those

sources with the largest impact on water quality. The iterative implementation of

pollution control actions in the watershed has several benefits:

1. It enables tracking of water quality improvements following implementation through follow-up stream monitoring;

2. It provides a measure of quality control, given the uncertainties inherent in computer simulation modeling;

3. It provides a mechanism for developing public support through periodic updates on implementation levels and water quality improvements;

4. It helps ensure that the most cost effective practices are implemented first; and

5. It allows for the evaluation of the adequacy of the TMDL in achieving water quality standards.

13.3 Implementation of Waste Load Allocations

Federal regulations require that all new or revised National Pollutant Discharge

Elimination System (NPDES) permits must be consistent with the assumptions and

requirements of any applicable TMDL WLA (40 CFR §122.44 (d)(1)(vii)(B)). All such

permits should be submitted to EPA for review.

13.3.1 Stormwater

VADEQ and VADCR coordinate separate state permitting programs that regulate the

management of pollutants carried by stormwater runoff. VADEQ regulates stormwater

discharges associated with industrial activities through its VPDES program, while

VADCR regulates stormwater discharges from construction sites, and from municipal

separate storm sewer systems (MS4s) through the VSMP program. Stormwater

discharges from coal mining operations are permitted through NPDES permits by the

Department of Mines, Minerals and Energy (DMME). As with non-stormwater permits,

all new or revised stormwater permits must be consistent with the assumptions and

requirements of any applicable TMDL WLA. If a WLA is based on conditions specified

in existing permits, and the permit conditions are being met, no additional actions may be



needed. If a WLA is based on reduced pollutant loads, additional pollutant control

actions will need to be implemented.

The Virginia Erosion and Sediment Control and Virginia Stormwater Management

Programs – administered by the Department of Conservation and Recreation and

delegated to local jurisdictions – provides the framework for implementing sediment

reduction BMPs throughout localities. More information regarding these programs can

be found at http://www.dcr.virginia.gov/soil_&_water/e&s.shtml.

13.3.1.1 Active Coal Mining Operations

In November 2005, the Department of Mines, Minerals and Energy, Division of Mined

Land Reclamation issued Guidance Memorandum No. 14-05 to address the

implementation of coal mining-related TMDL wasteload allocations. The memorandum

can be accessed on DEQ’s TMDL web page, http://www.deq.virginia.gov/tmdl. As of

December 1, 2005 the Division of Mined Land Reclamation (Division) has been

implementing the steps outlined in the memorandum regarding permit applications in

watersheds with adopted benthic Total Maximum Daily Loads (TMDLs). A brief

summary is provided below.

Generally, a BMP approach will be used in Virginia to meet WLAs in lieu of altered

effluent limitations for permitted coal mine point source discharges. DMME’s TMDL

coordinator will track assigned and available WLAs. Prior to approval of new NPDES

points within a TMDL watershed, the Division Water Quality staff will confer with the

TMDL coordinator and/or consult the WLA information folder to determine that a WLA

is available. Loadings for WLAs will be tracked using results of routine NPDES

monitoring. When tracking indicates that WLAs are being exceeded, the Division will

request the permittee to revise the BMPs to reduce waste loads.

13.3.2 TMDL Modifications for New or Expanding Discharges

Permits issued for facilities with wasteload allocations developed as part of a Total

Maximum Daily Load (TMDL) must be consistent with the assumptions and

requirements of these wasteload allocations (WLA), as per EPA regulations. In cases

where a proposed permit modification is affected by a TMDL WLA, permit and TMDL

http://www.dcr.virginia.gov/soil_&_water/e&s.shtml�

http://www.deq.virginia.gov/tmdl�



staff must coordinate to ensure that new or expanding discharges meet this requirement.

In 2005, VADEQ issued guidance memorandum 05-2011 describing the available

options and the process that should be followed under those circumstances, including

public participation, EPA approval, State Water Control Board actions, and coordination

between permit and TMDL staff. The guidance memorandum is available on VADEQ’s

web site at www.deq.virginia.gov/waterguidance/.

13.4 Implementation of Load Allocations

The TMDL program does not impart new implementation authorities. Therefore, the

Commonwealth intends to use existing programs to the fullest extent in order to attain its

water quality goals. The measures for non point source reductions, which can include the

use of better treatment technology and the installation of best management practices

(BMPs), are implemented in an iterative process that is described along with specific

BMPs in the TMDL implementation plan.

13.4.1 Implementation Plan Development

For the implementation of the TMDL’s LA component, a TMDL implementation plan

will be developed that addresses at a minimum the requirements specified in the Code of

Virginia, Section 62.1-44.19:7. State law directs the State Water Control Board to

“develop and implement a plan to achieve fully supporting status for impaired waters”.

The implementation plan “shall include the date of expected achievement of water quality

objectives, measurable goals, corrective actions necessary and the associated costs,

benefits and environmental impacts of addressing the impairments”. EPA outlines the

minimum elements of an approvable implementation plan in its 1999 “Guidance for

Water Quality-Based Decisions: The TMDL Process”. The listed elements include

implementation actions/management measures, timelines, legal or regulatory controls,

time required to attain water quality standards, monitoring plans and milestones for

attaining water quality standards.

In order to qualify for other funding sources, such as EPA’s Section 319 grants,

additional plan requirements may need to be met. The detailed process for developing an

implementation plan has been described in the “TMDL Implementation Plan Guidance



Manual”, published in July 2003 (VADCR & VADEQ, 2003). It is available upon

request from the VADEQ and VADCR TMDL project staff or at

www.deq.virginia.gov/tmdl/implans/ipguide.pdf.

Watershed stakeholders will have opportunities to provide input and to participate in the

development of the TMDL implementation plan. Regional and local offices of VADEQ,

VADCR, and other cooperating agencies are technical resources to assist in this

endeavor.

With successful completion of implementation plans, local stakeholders will have a

blueprint to restore impaired waters and enhance the value of their land and water

resources. Additionally, development of an approved implementation plan may enhance

opportunities for obtaining financial and technical assistance during implementation.

13.4.2 Staged Implementation Scenarios

The purpose of the staged implementation scenarios is to identify one or more

combinations of implementation actions that result in the reduction of controllable

sources to the maximum extent practicable using cost-effective, reasonable BMPs for

nonpoint source control. Among the most efficient bacterial BMPs for both urban and

rural watersheds are stream side fencing for cattle farms, pet waste clean-up programs,

and government or grant programs available to homeowners with failing septic systems

and installation of treatment systems for homeowners currently using straight pipes.

Among the most efficient sediment BMPs for both urban and rural watersheds are

infiltration and retention basins, riparian buffer zones, grassed waterways, streambank

protection and stabilization, and wetland development or enhancement.

The Division of Mined Land Reclamation applies each year for grants from the Federal

Office of Surface Mining (OSM) to conduct projects addresseing reclamation of

abandoned mine lands (AML). Personnel at DMLR oversee the process of reclamation

including desining reclamation plans, obtaining consents for rights of entry, publishing

public notices in local newspapers, advertising for construction contractors, inspecting

the contractor's work to ensure the site is reclaimed and the problems abated according to

the engineering design. The AML lands within the current project are expected to be



addressed using this mechanism by DMLR. A second option for these lands is remining

which is now being promoted by DMLR as an alternative way of dealing with the issue

of the limited amount of money. Remining has already been credited for eliminating

miles of old pre-law highwalls by taking second cuts on existing walls and covering and

revegetating acres of eroding outslopes.

Actions identified during TMDL implementation plan development that go beyond what

can be considered cost-effective and reasonable will only be included as implementation

actions, if there are reasonable grounds for assuming that these actions will in fact be

implemented.

If water quality standards are not met upon implementation of all cost-effective and

reasonable BMPs, a Use Attainability Analysis (UAA) may need to be initiated since

Virginia’s water quality standards allow for changes to use designations if existing water

quality standards cannot be attained by implementing effluent limits required under

§301b and §306 of Clean Water Act, and by implementing cost effective and reasonable

BMPs for nonpoint source control. Additional information on UAAs is presented in

Section 13.6. Stage I scenarios for the bacterial TMDL are discussed in Chapter 5.

13.4.3 Link to Ongoing Restoration Efforts

Implementation of this TMDL will contribute to on-going water quality improvement

efforts aimed at restoring water quality downstream in the Powell River watershed. The

water quality in the Powell River as impacted by sediment and bacteria will be improved

once the previously developed TMDLs for Straight and Callahan Creeks are

implemented.

13.4.4 Implementation Funding Sources

The implementation of pollutant reductions from non-regulated nonpoint sources relies

heavily on incentive-based programs. Therefore, the identification of funding sources for

non-regulated implementation activities is a key to success. Cooperating agencies,

organizations and stakeholders must identify potential funding sources available for

implementation during the development of the implementation plan in accordance with

the Virginia Guidance Manual for Total Maximum Daily Load Implementation Plans.



The TMDL Implementation Plan Guidance Manual contains information on a variety of

funding sources, as well as government agencies that might support implementation

efforts and suggestions for integrating TMDL implementation with other watershed

planning efforts.

Some of the major potential sources of funding for non-regulated implementation actions

may include the U.S. Department of Agriculture’s Conservation Reserve Enhancement

and Environmental Quality Incentive Programs, EPA Section 319 funds, the Virginia

State Revolving Loan Program (also available for permitted activities), the Virginia

Water Quality Improvement Fund (available for both point and nonpoint source

pollution), tax credits and landowner contributions.

With additional appropriations for the Water Quality Improvement Fund during the last

two legislative sessions, the Fund has become a significant funding source for

agricultural BMPs and wastewater treatment plants. Additionally, funding is being made

available to address urban and residential water quality problems. Information on WQIF

projects and allocations can be found at www.deq.virginia.gov/bay/wqif.html and at

www.dcr.virginia.gov/soil_&_water/wqia.shtml.

13.5 Follow-Up Monitoring

Monitoring is a vital aspect of the water quality improvement process. TMDLs.

Monitoring to support refinement of the phased TMDLs will begin as soon as is feasible

upon approval of the TMDLs, and will likely require a more intensive monitoring effort

than that which is described below for non-phased TMDLs. A revised TMDL document

is planned for submittal to EPA two years from the date that both the EPA Region III has


TMDL.

Following the development of the TMDL, VADEQ will make every effort to continue to

monitor the impaired streams in accordance with its ambient, biological, and PAHs

monitoring programs. VADEQ’s Ambient Watershed Monitoring Plan for conventional

pollutants calls for watershed monitoring to take place on a rotating basis, bi-monthly for

two consecutive years of a six-year cycle. In accordance with DEQ Guidance Memo No.



03-2004 (www.deq.virginia.gov/waterguidance/pdf/032004.pdf) (VADEQ, 2003a),

during periods of reduced resources, monitoring can temporarily discontinue until the

TMDL staff determines that implementation measures to address the source(s) of

impairments are being installed. Monitoring can resume at the start of the following

fiscal year, next scheduled monitoring station rotation, or where deemed necessary by the

regional office or TMDL staff, as a new special study. Since there may be a lag time of

one-to-several years before any improvement in the benthic community will be evident,

follow-up biological monitoring may not have to occur in the fiscal year immediately

following the implementation of control measures. The details of the follow-up ambient

and biological monitoring will be outlined in the Annual Water Monitoring Plan prepared

by each VADEQ Regional Office.

The objective of the Statewide Fish Tissue and Sediment Monitoring Program is to

systematically assess and evaluate, using a multi-tier screening, waterbodies in Virginia

in order to identify toxic contaminant(s) accumulation with the potential to adversely

affect human users of the resource. The details of the follow-up monitoring will be

outlined in the annual Fish Tissue and Sediment Monitoring Plan prepared by the

VADEQ Water Quality Standards and Biological Monitoring Programs, Office of Water

Quality Programs as well as the annual water monitoring plans prepared by the regional

offices. Other agency personnel, watershed stakeholders, etc. may provide input on the

Annual Water Monitoring Plan. These recommendations must be made to the VADEQ

regional TMDL coordinator by September 30 of each year.

The purpose, location, parameters, frequency, and duration of the monitoring will be

determined by the VADMME staff, in cooperation with VADEQ staff, the

Implementation Plan Steering Committee and local stakeholders. Whenever possible, the

location of the follow-up monitoring station(s) will be the same as the listing station. At

a minimum, the monitoring station must be representative of the original impaired

segment.

VADEQ staff, in cooperation with VADMME staff, the Implementation Plan Steering

Committee and local stakeholders, will continue to use data from the ambient monitoring

http://www.deq.virginia.gov/waterguidance/pdf/032004.pdf�



stations to evaluate reductions in pollutants (“water quality milestones” as established in

the IP), the effectiveness of the TMDL in attaining and maintaining water quality

standards, and the success of implementation efforts. Recommendations may then be

made, when necessary, to target implementation efforts in specific areas and continue or

discontinue monitoring at follow-up stations.

In some cases, watersheds will require monitoring above and beyond what is included in

VADEQ’s and VADMME’s standard monitoring plans. Ancillary monitoring by

citizens’ or watershed groups, local government, or universities is an option that may be

used in such cases. An effort should be made to ensure that ancillary monitoring follows

established QA/QC guidelines in order to maximize compatibility with VADEQ

monitoring data. In instances where citizens’ monitoring data are not available and

additional monitoring is needed to assess the effectiveness of targeting efforts, TMDL

staff may request of the monitoring managers in each regional office an increase in the

number of stations or to monitor existing stations at a higher frequency in the watershed.

The additional monitoring beyond the original bimonthly single station monitoring will

be contingent on staff resources and available laboratory budget. More information on

VADEQ’s citizen monitoring in Virginia and QA/QC guidelines is available at

www.deq.virginia.gov/cmonitor/.

To demonstrate that the watershed is meeting water quality standards in watersheds

where corrective actions have taken place (whether or not a TMDL or Implementation

plan has been completed), VADEQ must meet the minimum data requirements from the

original listing station or a station representative of the originally listed segment. The

minimum data requirement for conventional pollutants (bacteria, dissolved oxygen, etc)

is bimonthly monitoring for two consecutive years. For biological monitoring, the

minimum requirement is two consecutive samples (one in the spring and one in the fall)

in a one-year period.

13.6 Attainability of Designated Uses

In some streams for which TMDLs have been developed, factors may prevent the stream

from attaining its designated use.



In order for a stream to be assigned a new designated use, or a subcategory of a use, the

current designated use must be removed. To remove a designated use, the state must

demonstrate that the use is not an existing use, and that downstream uses are protected.

Such uses will be attained by implementing effluent limits required under §301b and

§306 of Clean Water Act and by implementing cost-effective and reasonable best

management practices for nonpoint source control (9 VAC 25-260-10 paragraph I).

The state must also demonstrate that attaining the designated use is not feasible because:

1. Naturally occurring pollutant concentration prevents the attainment of the use;

2. Natural, ephemeral, intermittent or low flow conditions prevent the attainment of the use unless these conditions may be compensated for by the discharge of sufficient volume of effluent discharges without violating state water conservation;

3. Human-caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place;

4. Dams, diversions or other types of hydrologic modifications preclude the attainment of the use, and it is not feasible to restore the waterbody to its original condition or to operate the modification in such a way that would result in the attainment of the use;

5. Physical conditions related to natural features of the water body, such as the lack of proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic life use protection; or

6. Controls more stringent than those required by §301b and §306 of the Clean Water Act would result in substantial and widespread economic and social impact.

This and other information is collected through a special study called a UAA. All site-

specific criteria or designated use changes must be adopted by the SWCB as amendments

to the water quality standards regulations. During the regulatory process, watershed

stakeholders and other interested citizens, as well as the EPA, will be able to provide

comment. Additional information can be obtained at

www.deq.virginia.gov/wqs/designated.html.

The process to address potentially unattainable reductions based on the above is as

follows:



As a first step, measures targeted at the controllable, anthropogenic sources identified in

the TMDL’s staged implementation scenarios will be implemented. The expectation is

that all controllable sources would be reduced to the maximum extent possible using the

implementation approaches described above. VADEQ will continue to monitor

biological health and water quality in the stream during and subsequent to the

implementation of these measures to determine if the water quality standard is attained.

This effort will also help to evaluate if the modeling assumptions were correct. In the

best-case scenario, water quality goals will be met and the stream’s uses fully restored

using effluent controls and BMPs. If, however, water quality standards are not being met,

and no additional effluent controls and BMPs can be identified, a UAA would then be

initiated with the goal of re-designating the stream for a more appropriate use or

subcategory of a use.

A 2006 amendment to the Code of Virginia under 62.1-44.19:7E. provides an opportunity

for aggrieved parties in the TMDL process to present to the State Water Control Board

reasonable grounds indicating that the attainment of the designated use for a water is not

feasible. The Board may then allow the aggrieved party to conduct a use attainability

analysis according to the criteria listed above and a schedule established by the Board.

The amendment further states that “If applicable, the schedule shall also address whether

TMDL development or implementation for the water shall be delayed”.


PUBLIC PARTICIPATION 14-1

14. PUBLIC PARTICIPATION

Public participation during TMDL development for the Powell River and Tributaries was

encouraged; a summary of the meetings is presented in Table 14.1. The first Technical

Advisory Committee (TAC) meeting took place on October 21, 2008 at the Pennington

Gap Town Hall in Pennington Gap, VA. The first public meeting was also held at the

Pennington Gap Town Hall on October 21, 2008. The meetings were publicized by

placing notices in the Virginia Register, signs in the watershed, and emailing notices to

local stakeholders and representatives. The final Technical Advisory Committee (TAC)

meeting took place on January 28, 2010 at the Department of Mines, Minerals, and

Energy in Big Stone Gap, VA. The final public meeting was also held at the Department

of Mines, Minerals, and Energy on January 28, 2010. The meetings were publicized by

placing notices in the Virginia Register, signs in the watershed, and emailing notices to

local stakeholders and representatives.

Table 14.1 Public participation during TMDL development for the Powell River and Tributaries study area.

Date Location Type

10/21/2008 Pennington Gap Town

Hall in Pennington Gap, VA

First TAC

10/21/2008 Pennington Gap Town

Hall in Pennington Gap, VA

First public

1/28/2010 Department of Mines, Minerals, and Energy,

Big Stone Gap, VA Final TAC

1/28/2010 Department of Mines, Minerals, and Energy,

Big Stone Gap, VA Final public

Public participation during the implementation plan development process will include the

formation of stakeholders’ committees, with committee and public meetings. Public

participation is critical to promote reasonable assurances that the implementation

activities will occur. Stakeholder committees will have the express purpose of

formulating the TMDL Implementation Plan. The committees will consist of, but not be

limited to, representatives from VADEQ, VADCR, and local governments. These

committees will have the responsibility for identifying corrective actions that are founded


14-2 PUBLIC PARTICIPATION

in practicality, establishing a time line to insure expeditious implementation, and setting

measurable goals and milestones for attaining water quality standards.


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Evans, Barry M., S. A. Sheeder, K. J. Corradini, and W. W. Brown. 2001. AVGWLF version 3.2 Users Guide. Environmental Resources Research Institute, Pennsylvania State University and Pennsylvania Department of Environmental Protection, Bureau of Watershed Conservation.

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Klemm, D.J., K.A. Blocksom, W.T. Thoeny, F.A. Fulk, A.T. Herlihy, P.R. Kauffman and S.M. Cormier. 2001. Methods Development and Use of Macroinvertebrates as Indicators of Ecological Conditions For Streams In The Mid-Atlantic Highlands Region. Environmental Monitoring and Assessment. 78: 169-212.

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Merricks, T.C. 2003. Evaluation of Hollow Fill Drainages and Associated Settling Ponds on Water Quality and Benthic Macroinvertebrate Communities in VA and WVA. MS thesis. Blacksburg, VA: Virginia Polytechnic Institute and State University. Departments of Biology and Crop and Soil Environmental Science.

Messinger, T. 2002. Polycyclic aromatic hydrocarbons in bottom sediment and bioavailability in streams in the New River Gorge National River and Gauley River National Recreation Area, West Virginia, 2002: U.S. Geological Survey Scientific Investigations Report 2004-5045, 24 p.


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GLOSSARY G-1

GLOSSARY

303(d). A section of the Clean Water Act of 1972 requiring states to identify and list water bodies that do not meet the states’ water quality standards.

Allocations. That portion of a receiving water's loading capacity attributed to one of its existing or future pollution sources (nonpoint or point) or to natural background sources. (A wasteload allocation [WLA] is that portion of the loading capacity allocated to an existing or future point source, and a load allocation [LA] is that portion allocated to an existing or future nonpoint source or to natural background levels. Load allocations are best estimates of the loading, which can range from reasonably accurate estimates to gross allotments, depending on the availability of data and appropriate techniques for predicting loading.)

Ambient water quality. Natural concentration of water quality constituents prior to mixing of either point or nonpoint source load of contaminants. Reference ambient concentration is used to indicate the concentration of a chemical that will not cause adverse impact on human health.

Anthropogenic. Pertains to the [environmental] influence of human activities.

Antidegradation Policies. Policies that are part of each states water quality standards. These policies are designed to protect water quality and provide a method of assessing activities that might affect the integrity of waterbodies.

Aquatic ecosystem. Complex of biotic and abiotic components of natural waters. The aquatic ecosystem is an ecological unit that includes the physical characteristics (such as flow or velocity and depth), the biological community of the water column and benthos, and the chemical characteristics such as dissolved solids, dissolved oxygen, and nutrients. Both living and nonliving components of the aquatic ecosystem interact and influence the properties and status of each component.

Assimilative capacity. The amount of contaminant load that can be discharged to a specific waterbody without exceeding water quality standards or criteria. Assimilative capacity is used to define the ability of a waterbody to naturally absorb and use a discharged substance without impairing water quality or harming aquatic life.

Background levels. Levels representing the chemical, physical, and biological conditions that would result from natural geomorphological processes such as weathering or dissolution.

Bacteria. Single-celled microorganisms. Bacteria of the coliform group are considered the primary indicators of fecal contamination and are often used to assess water quality.

Bacterial decomposition. Breakdown by oxidation, or decay, of organic matter by heterotrophic bacteria. Bacteria use the organic carbon in organic matter as the energy source for cell synthesis.


G-2 GLOSSARY

Benthic. Refers to material, especially sediment, at the bottom of an aquatic ecosystem. It can be used to describe the organisms that live on, or in, the bottom of a waterbody.

Benthic organisms. Organisms living in, or on, bottom substrates in aquatic ecosystems.

Best management practices (BMPs). Methods, measures, or practices determined to be reasonable and cost-effective means for a landowner to meet certain, generally nonpoint source, pollution control needs. BMPs include structural and nonstructural controls and operation and maintenance procedures.

Bioassessment. Evaluation of the condition of an ecosystem that uses biological surveys and other direct measurements of the resident biota.

Biochemical Oxygen Demand (BOD). Represents the amount of oxygen consumed by bacteria as they break down organic matter in the water.

Biological Integrity. A water body's ability to support and maintain a balanced, integrated adaptive assemblage of organisms with species composition, diversity, and functional organization comparable to that of similar natural, or non-impacted habitat.

Biometric. (Biological Metric) The study of biological phenomena by measurements and statistics.

Box and whisker plot. A graphical representation of the mean, lower quartile, upper quartile, upper limit, lower limit, and outliers of a data set.

Calibration. The process of adjusting model parameters within physically defensible ranges until the resulting predictions give a best possible good fit to observed data.

Cause. 1. That which produces an effect (a general definition). 2. A stressor or set of stressors that occur at an intensity, duration and frequency

of exposure that results in a change in the ecological condition (a SI-specific definition). 2

Channel. A natural stream that conveys water; a ditch or channel excavated for the flow of water.

Chloride. An atom of chlorine in solution; an ion bearing a single negative charge.

Clean Water Act (CWA). The Clean Water Act (formerly referred to as the Federal Water Pollution Control Act or Federal Water Pollution Control Act Amendments of 1972), Public Law 92-500, as amended by Public Law 96-483 and Public Law 97-117, 33 U.S.C. 1251 et seq. The Clean Water Act (CWA) contains a number of provisions to restore and maintain the quality of the nation's water resources. One of these provisions is Section 303(d), which establishes the TMDL program.

Concentration. Amount of a substance or material in a given unit volume of solution; usually measured in milligrams per liter (mg/L) or parts per million (ppm).


GLOSSARY G-3

Concentration-based limit. A limit based on the relative strength of a pollutant in a waste stream, usually expressed in milligrams per liter (mg/L).

Concentration-response model. A quantitative (usually statistical) model of the relationship between the concentration of a chemical to which a population or community of organisms is exposed and the frequency or magnitude of a biological response. (2)

Conductivity. An indirect measure of the presence of dissolved substances within water.

Confluence. The point at which a river and its tributary flow together.

Contamination. The act of polluting or making impure; any indication of chemical, sediment, or biological impurities.

Continuous discharge. A discharge that occurs without interruption throughout the operating hours of a facility, except for infrequent shutdowns for maintenance, process changes, or other similar activities.

Conventional pollutants. As specified under the Clean Water Act, conventional contaminants include suspended solids, coliform bacteria, high biochemical oxygen demand, pH, and oil and grease.

Conveyance. A measure of the of the water carrying capacity of a channel section. It is directly proportional to the discharge in the channel section.

Cost-share program. A program that allocates project funds to pay a percentage of the cost of constructing or implementing a best management practice. The remainder of the costs is paid by the producer(s).

Cross-sectional area. Wet area of a waterbody normal to the longitudinal component of the flow.

Critical condition. The critical condition can be thought of as the "worst case" scenario of environmental conditions in the waterbody in which the loading expressed in the TMDL for the pollutant of concern will continue to meet water quality standards. Critical conditions are the combination of environmental factors (e.g., flow, temperature, etc.) that results in attaining and maintaining the water quality criterion and has an acceptably low frequency of occurrence.

Decay. The gradual decrease in the amount of a given substance in a given system due to various sink processes including chemical and biological transformation, dissipation to other environmental media, or deposition into storage areas.

Decomposition. Metabolic breakdown of organic materials; the formation of by-products of decomposition releases energy and simple organic and inorganic compounds. See also Respiration.


G-4 GLOSSARY

Designated uses. Those uses specified in water quality standards for each waterbody or segment whether or not they are being attained.

Dilution. The addition of some quantity of less-concentrated liquid (water) that results in a decrease in the original concentration.

Direct runoff. Water that flows over the ground surface or through the ground directly into streams, rivers, and lakes.

Discharge. Flow of surface water in a stream or canal, or the outflow of groundwater from a flowing artesian well, ditch, or spring. Can also apply to discharge of liquid effluent from a facility or to chemical emissions into the air through designated venting mechanisms.

Discharge Monitoring Report (DMR). Report of effluent characteristics submitted by a municipal or industrial facility that has been granted an NPDES discharge permit.

Discharge permits (under NPDES). A permit issued by the EPA or a state regulatory agency that sets specific limits on the type and amount of pollutants that a municipality or industry can discharge to a receiving water; it also includes a compliance schedule for achieving those limits. The permit process was established under the National Pollutant Discharge Elimination System, under provisions of the Federal Clean Water Act.

Dispersion. The spreading of chemical or biological constituents, including pollutants, in various directions at varying velocities depending on the differential in-stream flow characteristics.

Dissolved Oxygen (DO). The amount of oxygen in water. DO is a measure of the amount of oxygen available for biochemical activity in a waterbody.

Diurnal. Actions or processes that have a period or a cycle of approximately one tidal-day or are completed within a 24-hour period and that recur every 24 hours. Also, the occurrence of an activity/process during the day rather than the night.

DNA. Deoxyribonucleic acid. The genetic material of cells and some viruses.

Domestic wastewater. Also called sanitary wastewater, consists of wastewater discharged from residences and from commercial, institutional, and similar facilities.

Drainage basin. A part of a land area enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into a receiving water. Also referred to as a watershed, river basin, or hydrologic unit.

Dynamic model. A mathematical formulation describing and simulating the physical behavior of a system or a process and its temporal variability.

Dynamic simulation. Modeling of the behavior of physical, chemical, and/or biological phenomena and their variations over time.


GLOSSARY G-5

Ecoregion. A region defined in part by its shared characteristics. These include meteorological factors, elevation, plant and animal speciation, landscape position, and soils.

Ecosystem. An interactive system that includes the organisms of a natural community association together with their abiotic physical, chemical, and geochemical environment.

Effluent. Municipal sewage or industrial liquid waste (untreated, partially treated, or completely treated) that flows out of a treatment plant, septic system, pipe, etc.

Effluent guidelines. The national effluent guidelines and standards specify the achievable effluent pollutant reduction that is attainable based upon the performance of treatment technologies employed within an industrial category. The National Effluent Guidelines Program was established with a phased approach whereby industry would first be required to meet interim limitations based on best practicable control technology currently available for existing sources (BPT). The second level of effluent limitations to be attained by industry was referred to as best available technology economically achievable (BAT), which was established primarily for the control of toxic pollutants.

Effluent limitation. Restrictions established by a state or EPA on quantities, rates, and concentrations in pollutant discharges.

Endpoint. An endpoint (or indicator/target) is a characteristic of an ecosystem that may be affected by exposure to a stressor. Assessment endpoints and measurement endpoints are two distinct types of endpoints commonly used by resource managers. An assessment endpoint is the formal expression of a valued environmental characteristic and should have societal relevance (an indicator). A measurement endpoint is the expression of an observed or measured response to a stress or disturbance. It is a measurable environmental characteristic that is related to the valued environmental characteristic chosen as the assessment endpoint. The numeric criteria that are part of traditional water quality standards are good examples of measurement endpoints (targets).

Enhancement. In the context of restoration ecology, any improvement of a structural or functional attribute.

Erosion. The detachment and transport of soil particles by water and wind. Sediment resulting from soil erosion represents the single largest source of nonpoint pollution in the United States.

Eutrophication. The process of enrichment of water bodies by nutrients. Waters receiving excessive nutrients may become eutrophic, are often undesirable for recreation, and may not support normal fish populations.

Evapotranspiration. The combined effects of evaporation and transpiration on the water balance. Evaporation is water loss into the atmosphere from soil and water surfaces. Transpiration is water loss into the atmosphere as part of the life cycle of plants.


G-6 GLOSSARY

Fate of pollutants. Physical, chemical, and biological transformation in the nature and changes of the amount of a pollutant in an environmental system. Transformation processes are pollutant-specific. Because they have comparable kinetics, different formulations for each pollutant are not required.

Feedlot. A confined area for the controlled feeding of animals. Tends to concentrate large amounts of animal waste that cannot be absorbed by the soil and, hence, may be carried to nearby streams or lakes by rainfall runoff.

Flux. Movement and transport of mass of any water quality constituent over a given period of time. Units of mass flux are mass per unit time.

General Standard. A narrative standard that ensures the general health of state waters. All state waters, including wetlands, shall be free from substances attributable to sewage, industrial waste, or other waste in concentrations, amounts, or combinations which contravene established standards or interfere directly or indirectly with designated uses of such water or which are inimical or harmful to human, animal, plant, or aquatic life (9VAC25-260-20). (4)

GIS. Geographic Information System. A system of hardware, software, data, people, organizations and institutional arrangements for collecting, storing, analyzing and disseminating information about areas of the earth. (Dueker and Kjerne, 1989)

Ground water. The supply of fresh water found beneath the earth’s surface, usually in aquifers, which supply wells and springs. Because ground water is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants and leaking underground storage tanks.

HSPF. Hydrological Simulation Program – Fortran. A computer simulation tool used to mathematically model nonpoint source pollution sources and movement of pollutants in a watershed.

Hydrograph. A graph showing variation of stage (depth) or discharge in a stream over a period of time.

Hydrologic cycle. The circuit of water movement from the atmosphere to the earth and its return to the atmosphere through various stages or processes, such as precipitation, interception, runoff, infiltration, storage, evaporation, and transpiration.

Hydrology. The study of the distribution, properties, and effects of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere.

Impairment. A detrimental effect on the biological integrity of a water body that prevents attainment of the designated use.

IMPLND. An impervious land segment in HSPF. It is used to model land covered by impervious materials, such as pavement.


GLOSSARY G-7

Indicator. A measurable quantity that can be used to evaluate the relationship between pollutant sources and their impact on water quality.

Indicator organism. An organism used to indicate the potential presence of other (usually pathogenic) organisms. Indicator organisms are usually associated with the other organisms, but are usually more easily sampled and measured.

Indirect causation. The induction of effects through a series of cause-effect relationships, so that the impaired resource may not even be exposed to the initial cause.

Indirect effects. Changes in a resource that are due to a series of cause-effect relationships rather than to direct exposure to a contaminant or other stressor.

Infiltration capacity. The capacity of a soil to allow water to infiltrate into or through it during a storm.

In situ. In place; in situ measurements consist of measurements of components or processes in a full-scale system or a field, rather than in a laboratory.

Interflow. Runoff that travels just below the surface of the soil.

Leachate. Water that collects contaminants as it trickles through wastes, pesticides, or fertilizers. Leaching can occur in farming areas, feedlots, and landfills and can result in hazardous substances entering surface water, ground water, or soil.

Limits (upper and lower). The lower limit equals the lower quartile – 1.5x(upper quartile – lower quartile), and the upper limit equals the upper quartile + 1.5x(upper quartile – lower quartile). Values outside these limits are referred to as outliers.

Loading, Load, Loading rate. The total amount of material (pollutants) entering the system from one or multiple sources; measured as a rate in weight per unit time.

Load allocation (LA). The portion of a receiving waters loading capacity attributed either to one of its existing or future nonpoint sources of pollution or to natural background sources. Load allocations are best estimates of the loading, which can range from reasonably accurate estimates to gross allotments, depending on the availability of data and appropriate techniques for predicting the loading. Wherever possible, natural and nonpoint source loads should be distinguished (40 CFR 130.2(g)).

Loading capacity (LC). The greatest amount of loading a water can receive without violating water quality standards.

Margin of safety (MOS). A required component of the TMDL that accounts for the uncertainty about the relationship between the pollutant loads and the quality of the receiving waterbody (CWA Section 303(d)(1)(C)). The MOS is normally incorporated into the conservative assumptions used to develop TMDLs (generally within the calculations or models) and approved by the EPA either individually or in state/EPA agreements. If the MOS needs to be larger than that which is allowed through the


G-8 GLOSSARY

conservative assumptions, additional MOS can be added as a separate component of the TMDL (in this case, quantitatively, a TMDL = LC = WLA + LA + MOS).

Mass balance. An equation that accounts for the flux of mass going into a defined area and the flux of mass leaving the defined area. The flux in must equal the flux out.

Mass loading. The quantity of a pollutant transported to a waterbody.

Mean. The sum of the values in a data set divided by the number of values in the data set.

Metric ton (Mg or t). A unit of mass equivalent to 1,000 kilograms. An annual load of a pollutant is typically reported in metric tons per year (t/yr).

Metrics. Indices or parameters used to measure some aspect or characteristic of a water body's biological integrity. The metric changes in some predictable way with changes in water quality or habitat condition.

MGD. Million gallons per day. A unit of water flow, whether discharge or withdraw.

Mitigation. Actions taken to avoid, reduce, or compensate for the effects of environmental damage. Among the broad spectrum of possible actions are those that restore, enhance, create, or replace damaged ecosystems.

Model. Mathematical representation of hydrologic and water quality processes. Effects of land use, slope, soil characteristics, and management practices are included.

Monitoring. Periodic or continuous surveillance or testing to determine the level of compliance with statutory requirements and/or pollutant levels in various media or in humans, plants, and animals.

Mood’s Median Test. A nonparametric (distribution-free) test used to test the equality of medians from two or more populations.

Most Probable Stressor(s): The stressor(s) with the most consistent information linking it with the poorer benthic and habitat metrics was considered to be the most probable stressor(s).

Narrative criteria. Nonquantitative guidelines that describe the desired water quality goals.

National Pollutant Discharge Elimination System (NPDES). The national program for issuing, modifying, revoking and re-issuing, terminating, monitoring, and enforcing permits, and imposing and enforcing pretreatment requirements, under sections 307, 402, 318, and 405 of the Clean Water Act.

Natural waters. Flowing water within a physical system that has developed without human intervention, in which natural processes continue to take place.


GLOSSARY G-9

Nitrogen. An essential nutrient to the growth of organisms. Excessive amounts of nitrogen in water can contribute to abnormally high growth of algae, reducing light and oxygen in aquatic ecosystems.

Nonpoint source. Pollution that originates from multiple sources over a relatively large area. Nonpoint sources can be divided into source activities related to either land or water use including failing septic tanks, improper animal-keeping practices, forest practices, and urban and rural runoff.

Non-Stressor(s): Those stressors with data indicating normal conditions, without water quality standard violations, or without the observable impacts usually associated with a specific stressor, were eliminated as possible stressors.

Numeric targets. A measurable value determined for the pollutant of concern, which, if achieved, is expected to result in the attainment of water quality standards in the listed waterbody.

Numerical model. Model that approximates a solution of governing partial differential equations, which describe a natural process. The approximation uses a numerical discretization of the space and time components of the system or process.

Nutrient. An element or compound essential to life, including carbon, oxygen, nitrogen, phosphorus, and many others: as a pollutant, any element or compound, such as phosphorus or nitrogen, that in excessive amounts contributes to abnormally high growth of algae, reducing light and oxygen in aquatic ecosystems.

Organic matter. The organic fraction that includes plant and animal residue at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by the soil population. Commonly determined as the amount of organic material contained in a soil or water sample.

Parameter. A numerical descriptive measure of a population. Since it is based on the observations of the population, its value is almost always unknown.

Peak runoff. The highest value of the stage or discharge attained by a flood or storm event; also referred to as flood peak or peak discharge.

PERLND. A pervious land segment in HSPF. It is used to model a particular land use segment within a subwatershed (e.g. pasture, urban land, or crop land).

Permit. An authorization, license, or equivalent control document issued by the EPA or an approved federal, state, or local agency to implement the requirements of an environmental regulation; e.g., a permit to operate a wastewater treatment plant or to operate a facility that may generate harmful emissions.

Permit Compliance System (PCS). Computerized management information system that contains data on NPDES permit-holding facilities. PCS keeps extensive records on more


G-10 GLOSSARY

than 65,000 active water-discharge permits on sites located throughout the nation. PCS tracks permit, compliance, and enforcement status of NPDES facilities.

Phased/staged approach. Under the phased approach to TMDL development, load allocations and wasteload allocations are calculated using the best available data and information recognizing the need for additional monitoring data to accurately characterize sources and loadings. The phased approach is typically employed when nonpoint sources dominate. It provides for the implementation of load reduction strategies while collecting additional data.

Phosphorus. An essential nutrient to the growth of organisms. Excessive amounts of phosphorus in water can contribute to abnormally high growth of algae, reducing light and oxygen in aquatic ecosystems.

Point source. Pollutant loads discharged at a specific location from pipes, outfalls, and conveyance channels from either municipal wastewater treatment plants or industrial waste treatment facilities. Point sources can also include pollutant loads contributed by tributaries to the main receiving water stream or river.

Pollutant. Dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial, municipal, and agricultural waste discharged into water. (CWA section 502(6)).

Pollution. Generally, the presence of matter or energy whose nature, location, or quantity produces undesired environmental effects. Under the Clean Water Act, for example, the term is defined as the man-made or man-induced alteration of the physical, biological, chemical, and radiological integrity of water.

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. PAHs occur in oil, coal, and tar deposits, and are produced as byproducts of fuel burning (whether fossil fuel or biomass). As a pollutant, they are of concern because some compounds have been identified as carcinogenic, mutagenic, and teratogenic.

Possible Stressor(s): Those stressors with data indicating possible links, but inconclusive data, were considered to be possible stressors.

Postaudit. A subsequent examination and verification of a model's predictive performance following implementation of an environmental control program.

Privately owned treatment works. Any device or system that is (a) used to treat wastes from any facility whose operator is not the operator of the treatment works and (b) not a publicly owned treatment works.

Public comment period. The time allowed for the public to express its views and concerns regarding action by the EPA or states (e.g., a Federal Register notice of a proposed rule-making, a public notice of a draft permit, or a Notice of Intent to Deny).

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GLOSSARY G-11

Publicly owned treatment works (POTW). Any device or system used in the treatment (including recycling and reclamation) of municipal sewage or industrial wastes of a liquid nature that is owned by a state or municipality. This definition includes sewers, pipes, or other conveyances only if they convey wastewater to a POTW providing treatment.

Quartile. The 25th, 50th, and 75th percentiles of a data set. A percentile (p) of a data set ordered by magnitude is the value that has at most p% of the measurements in the data set below it, and (100-p)% above it. The 50th quartile is also known as the median. The 25th and 75th quartiles are referred to as the lower and upper quartiles, respectively.

Rapid Bioassessment Protocol II (RBP II). A suite of measurements based on a quantitative assessment of benthic macroinvertebrates and a qualitative assessment of their habitat. RBP II scores are compared to a reference condition or conditions to determine to what degree a water body may be biologically impaired.

Reach. Segment of a stream or river.

Receiving waters. Creeks, streams, rivers, lakes, estuaries, ground-water formations, or other bodies of water into which surface water and/or treated or untreated waste are discharged, either naturally or in man-made systems.

Reference Conditions. The chemical, physical, or biological quality or condition exhibited at either a single site or an aggregation of sites that are representative of non-impaired conditions for a watershed of a certain size, land use distribution, and other related characteristics. Reference conditions are used to describe reference sites.

Reserve capacity. Pollutant loading rate set aside in determining stream waste load allocation, accounting for uncertainty and future growth.

Residence time. Length of time that a pollutant remains within a section of a stream or river. The residence time is determined by the streamflow and the volume of the river reach or the average stream velocity and the length of the river reach.

Restoration. Return of an ecosystem to a close approximation of its presumed condition prior to disturbance.

Riparian areas. Areas bordering streams, lakes, rivers, and other watercourses. These areas have high water tables and support plants that require saturated soils during all or part of the year. Riparian areas include both wetland and upland zones.

Riparian zone. The border or banks of a stream. Although this term is sometimes used interchangeably with floodplain, the riparian zone is generally regarded as relatively narrow compared to a floodplain. The duration of flooding is generally much shorter, and the timing less predictable, in a riparian zone than in a river floodplain.


G-12 GLOSSARY

Roughness coefficient. A factor in velocity and discharge formulas representing the effects of channel roughness on energy losses in flowing water. Manning's "n" is a commonly used roughness coefficient.

Runoff. That part of precipitation, snowmelt, or irrigation water that runs off the land into streams or other surface water. It can carry pollutants from the air and land into receiving waters.

Seasonal Kendall test. A statistical tool used to test for trends in data, which is unaffected by seasonal cycles. (Gilbert, 1987)

Sediment. In the context of water quality, soil particles, sand, and minerals dislodged from the land and deposited into aquatic systems as a result of erosion.

Septic system. An on-site system designed to treat and dispose of domestic sewage. A typical septic system consists of a tank that receives waste from a residence or business and a drain field or subsurface absorption system consisting of a series of percolation lines for the disposal of the liquid effluent. Solids (sludge) that remain after decomposition by bacteria in the tank must be pumped out periodically.

Sewer. A channel or conduit that carries wastewater and storm water runoff from the source to a treatment plant or receiving stream. Sanitary sewers carry household, industrial, and commercial waste. Storm sewers carry runoff from rain or snow. Combined sewers handle both.

Simulation. The use of mathematical models to approximate the observed behavior of a natural water system in response to a specific known set of input and forcing conditions. Models that have been validated, or verified, are then used to predict the response of a natural water system to changes in the input or forcing conditions.

Slope. The degree of inclination to the horizontal. Usually expressed as a ratio, such as 1:25 or 1 on 25, indicating one unit vertical rise in 25 units of horizontal distance, or in a decimal fraction (0.04), degrees (2 degrees 18 minutes), or percent (4 percent).

Source. An origination point, area, or entity that releases or emits a stressor. A source can alter the normal intensity, frequency, or duration of a natural attribute, whereby the attribute then becomes a stressor.

Spatial segmentation. A numerical discretization of the spatial component of a system into one or more dimensions; forms the basis for application of numerical simulation models.

Staged Implementation. A process that allows for the evaluation of the adequacy of the TMDL in achieving the water quality standard. As stream monitoring continues to occur, staged or phased implementation allows for water quality improvements to be recorded as they are being achieved. It also provides a measure of quality control, and it helps to ensure that the most cost-effective practices are implemented first.


GLOSSARY G-13

Stakeholder. Any person with a vested interest in the TMDL development.

Standard. In reference to water quality (e.g. 200 cfu/100 mL geometric mean limit).

Standard deviation. A measure of the variability of a data set. The positive square root of the variance of a set of measurements.

Standard error. The standard deviation of a distribution of a sample statistic, esp. when the mean is used as the statistic.

Statistical significance. An indication that the differences being observed are not due to random error. The p-value indicates the probability that the differences are due to random error (i.e. a low p-value indicates statistical significance).

Steady-state model. Mathematical model of fate and transport that uses constant values of input variables to predict constant values of receiving water quality concentrations. Model variables are treated as not changing with respect to time.

Storm runoff. Storm water runoff, snowmelt runoff, and surface runoff and drainage; rainfall that does not evaporate or infiltrate the ground because of impervious land surfaces or a soil infiltration rate lower than rainfall intensity, but instead flows onto adjacent land or into waterbodies or is routed into a drain or sewer system.

Streamflow. Discharge that occurs in a natural channel. Although the term "discharge" can be applied to the flow of a canal, the word "streamflow" uniquely describes the discharge in a surface stream course. The term "streamflow" is more general than "runoff" since streamflow may be applied to discharge whether or not it is affected by diversion or regulation.

Stream Reach. A straight portion of a stream.

Stream restoration. Various techniques used to replicate the hydrological, morphological, and ecological features that have been lost in a stream because of urbanization, farming, or other disturbance.

Stressor. Any physical, chemical, or biological entity that can induce an adverse response. 2

Surface area. The area of the surface of a waterbody; best measured by planimetry or the use of a geographic information system.

Surface runoff. Precipitation, snowmelt, or irrigation water in excess of what can infiltrate the soil surface and be stored in small surface depressions; a major transporter of nonpoint source pollutants.

Surface water. All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.) and all springs, wells, or other collectors directly influenced by surface water.


G-14 GLOSSARY

Suspended Solids. Usually fine sediments and organic matter. Suspended solids limit sunlight penetration into the water, inhibit oxygen uptake by fish, and alter aquatic habitat.

Technology-based standards. Effluent limitations applicable to direct and indirect sources that are developed on a category-by-category basis using statutory factors, not including water quality effects.

Timestep. An increment of time in modeling terms. The smallest unit of time used in a mathematical simulation model (e.g. 15-minutes, 1-hour, 1-day).

Ton (T). A unit of measure of mass equivalent to 2,200 English lbs.

Topography. The physical features of a geographic surface area including relative elevations and the positions of natural and man-made features.

Total Dissolved Solids (TDS). A measure of the concentration of dissolved inorganic chemicals in water.

Total Maximum Daily Load (TMDL). The sum of the individual wasteload allocations (WLAs) for point sources, load allocations (LAs) for nonpoint sources and natural background, plus a margin of safety (MOS). TMDLs can be expressed in terms of mass per time, toxicity, or other appropriate measures that relate to a state's water quality standard.

TMDL Implementation Plan. A document required by Virginia statute detailing the suite of pollution control measures needed to remediate an impaired stream segment. The plans are also required to include a schedule of actions, costs, and monitoring. Once implemented, the plan should result in the previously impaired water meeting water quality standards and achieving a "fully supporting" use support status.

Transport of pollutants (in water). Transport of pollutants in water involves two main processes: (1) advection, resulting from the flow of water, and (2) dispersion, or transport due to turbulence in the water.

Tributary. A lower order-stream compared to a receiving waterbody. "Tributary to" indicates the largest stream into which the reported stream or tributary flows.

Urban Runoff. Surface runoff originating from an urban drainage area including streets, parking lots, and rooftops.

Validation (of a model). Process of determining how well the mathematical model's computer representation describes the actual behavior of the physical processes under investigation. A validated model will have also been tested to ascertain whether it accurately and correctly solves the equations being used to define the system simulation.


GLOSSARY G-15

Variance. A measure of the variability of a data set. The sum of the squared deviations (observation – mean) divided by (number of observations) – 1.

VADACS. Virginia Department of Agriculture and Consumer Services.

VADCR. Virginia Department of Conservation and Recreation.

VADEQ. Virginia Department of Environmental Quality.

VDH. Virginia Department of Health.

Wasteload allocation (WLA). The portion of a receiving waters' loading capacity that is allocated to one of its existing or future point sources of pollution. WLAs constitute a type of water quality-based effluent limitation (40 CFR 130.2(h)).

Wastewater. Usually refers to effluent from a sewage treatment plant. See also Domestic wastewater.

Wastewater treatment. Chemical, biological, and mechanical procedures applied to an industrial or municipal discharge or to any other sources of contaminated water to remove, reduce, or neutralize contaminants.

Water quality. The biological, chemical, and physical conditions of a waterbody. It is a measure of a waterbody's ability to support beneficial uses.

Water quality-based permit. A permit with an effluent limit more stringent than one based on technology performance. Such limits might be necessary to protect the designated use of receiving waters (e.g., recreation, irrigation, industry, or water supply).

Water quality criteria. Levels of water quality expected to render a body of water suitable for its designated use, composed of numeric and narrative criteria. Numeric criteria are scientifically derived ambient concentrations developed by the EPA or states for various pollutants of concern to protect human health and aquatic life. Narrative criteria are statements that describe the desired water quality goal. Criteria are based on specific levels of pollutants that would make the water harmful if used for drinking, swimming, farming, fish production, or industrial processes.

Water quality standard. Law or regulation that consists of the beneficial designated use or uses of a waterbody, the numeric and narrative water quality criteria that are necessary to protect the use or uses of that particular waterbody, and an antidegradation statement.

Watershed. A drainage area or basin in which all land and water areas drain or flow toward a central collector such as a stream, river, or lake at a lower elevation.

WQIA. Water Quality Improvement Act.


APPENDIX A A-1

APPENDIX A- CURRENT CONDITIONS FECAL COLIFORM LOADS

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Table A.1 Current conditions of land applied fecal coliform load for POW01A94 by land use (Sub-watersheds 1, 2, 3, 4, 5, 35, 36, 37, 44, 45):

Land-use Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Annual Total Load (cfu/yr)

Active Mining

52.6E11 47.5E11 52.6E11 50.9E11 52.6E11 50.9E11 52.6E11 52.6E11 50.9E11 52.6E11 50.9E11 52.6E11 61.9E12

AML 58.7E11 53.0E11 58.7E11 56.8E11 58.7E11 56.8E11 58.7E11 58.7E11 56.8E11 58.7E11 56.8E11 58.7E11 69.1E12 Barren 16.5E09 14.9E09 16.5E09 16.0E09 16.5E09 16.0E09 16.5E09 16.5E09 16.0E09 16.5E09 16.0E09 16.5E09 19.5E10 Comm. 73.2E10 66.1E10 73.2E10 70.8E10 73.2E10 70.8E10 73.2E10 73.2E10 70.8E10 73.2E10 70.8E10 73.2E10 86.2E11

Cropland 10.5E09 95.0E08 10.5E09 10.2E09 10.5E09 10.2E09 10.5E09 10.5E09 10.2E09 10.5E09 10.2E09 10.5E09 12.4E10 Forest 49.2E12 44.4E12 49.2E12 47.6E12 49.2E12 47.6E12 49.2E12 49.2E12 47.6E12 49.2E12 47.6E12 49.2E12 57.9E13

Past/Hay 80.0E09 72.3E09 80.0E09 77.4E09 80.0E09 77.4E09 80.0E09 80.0E09 77.4E09 80.0E09 77.4E09 80.0E09 94.2E10 Residential 26.4E12 23.4E12 24.9E12 23.5E12 23.8E12 22.5E12 22.2E12 22.2E12 21.5E12 21.7E12 21.5E12 24.3E12 27.8E13

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IX A

Table A.2 Monthly, directly deposited fecal coliform loads in each reach of POW01A94 (Reaches 1, 2, 3, 4, 5, 35, 36, 37, 44, 45).

Source Type

Reach ID Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

Annual Total Load

(cfu/yr) Human/Pet 1 38.7E10 35.0E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 45.6E11 Livestock 1 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 1 13.8E10 12.5E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 16.3E11

Human/Pet 2 44.3E11 40.0E11 44.3E11 42.9E11 44.3E11 42.9E11 44.3E11 44.3E11 42.9E11 44.3E11 42.9E11 44.3E11 52.2E12 Livestock 2 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 2 30.3E10 27.4E10 30.3E10 29.3E10 30.3E10 29.3E10 30.3E10 30.3E10 29.3E10 30.3E10 29.3E10 30.3E10 35.7E11


Human/Pet 4 19.1E11 17.3E11 19.1E11 18.5E11 19.1E11 18.5E11 19.1E11 19.1E11 18.5E11 19.1E11 18.5E11 19.1E11 22.5E12

Livestock 4 51.1E08 46.1E08 73.0E08 98.9E08 10.2E09 12.0E09 12.4E09 12.4E09 98.9E08 73.0E08 70.6E08 51.1E08 10.3E10 Wildlife 4 17.7E10 16.0E10 17.7E10 17.1E10 17.7E10 17.1E10 17.7E10 17.7E10 17.1E10 17.7E10 17.1E10 17.7E10 20.8E11


Human/Pet 35 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Livestock 35 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 35 17.7E10 16.0E10 17.7E10 17.1E10 17.7E10 17.1E10 17.7E10 17.7E10 17.1E10 17.7E10 17.1E10 17.7E10 20.8E11


TMD

L Developm

ent

Powell R


A-4

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr) Livestock 36 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 36 14.6E10 13.2E10 14.6E10 14.1E10 14.6E10 14.1E10 14.6E10 14.6E10 14.1E10 14.6E10 14.1E10 14.6E10 17.2E11



Livestock 44 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 44 12.1E10 10.9E10 12.1E10 11.7E10 12.1E10 11.7E10 12.1E10 12.1E10 11.7E10 12.1E10 11.7E10 12.1E10 14.3E11


TMD

L Developm

ent

Powell R


A-5

A

PPEND

IX A

Table A.3 Existing annual loads from direct-deposition sources for the POW01A94 (Reaches 1, 2, 3, 4, 5, 35, 36, 37, 44, 45): Source Annual Total Load (cfu/yr)beaver 22.1E09

Beef Calf 26.4E09 Beef Stocker 76.9E09 Dairy Calf 00E00

Dairy Milker 00E00 Dairy Replace. 00E00

Deer 22.6E09 Duck 63.3E08 Goose 39.4E10 Horse 00E00

Muskrat 21.8E12 Straight Pipes 17.8E13

Raccoon 63.5E10 Sheep 00E00 Swine 00E00 Turkey 98.8E05

TMD

L Developm

ent

Powell R


A-6

A

PPEND

IX A

Table A.4 Current conditions of land applied fecal coliform load for PLL02A00 by land use(Sub-watersheds 27, 28, 29):

Land-use Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Annual Total Load

(cfu/yr) Barren 86.8E08 78.4E08 86.8E08 84.0E08 86.8E08 84.0E08 86.8E08 86.8E08 84.0E08 86.8E08 84.0E08 86.8E08 10.2E10 Comm. 18.0E08 16.2E08 18.0E08 17.4E08 18.0E08 17.4E08 18.0E08 18.0E08 17.4E08 18.0E08 17.4E08 18.0E08 21.2E09

Cropland 16.3E09 14.7E09 16.3E09 15.7E09 16.3E09 15.7E09 16.3E09 16.3E09 15.7E09 16.3E09 15.7E09 16.3E09 19.1E10 Forest 11.2E12 10.1E12 11.2E12 10.9E12 11.2E12 10.9E12 11.2E12 11.2E12 10.9E12 11.2E12 10.9E12 11.2E12 13.2E13 LAX 23.0E10 20.7E10 28.5E10 34.6E10 35.8E10 40.0E10 41.3E10 41.3E10 34.6E10 28.5E10 27.5E10 26.9E10 38.3E11


Table A.5 Monthly, directly deposited fecal coliform loads in each reach of PLL02A00 (Reaches 27, 28, 29). Source Type


Annual Total Load (cfu/yr)


Human/Pet 28 10.4E11 94.2E10 10.4E11 10.1E11 10.4E11 10.1E11 10.4E11 10.4E11 10.1E11 10.4E11 10.1E11 10.4E11 12.3E12 Livestock 28 17.9E08 16.2E08 25.6E08 34.6E08 35.8E08 42.1E08 43.5E08 43.5E08 34.6E08 25.6E08 24.7E08 17.9E08 36.2E09 Wildlife 28 14.3E10 12.9E10 14.3E10 13.9E10 14.3E10 13.9E10 14.3E10 14.3E10 13.9E10 14.3E10 13.9E10 14.3E10 16.9E11


TMD

L Developm

ent

Powell R


A-7

A

PPEND

IX A

Table A.6 Existing annual loads from direct-deposition sources for the PLL02A00 (Reaches 27, 28, 29): Source Annual Total Load (cfu/yr)beaver 48.9E08






TMD

L Developm

ent

Powell R


A-8

A

PPEND

IX A

Table A.7 Current conditions of land applied fecal coliform load for BUH01A04 by land use (Sub-watersheds 33, 34).

Land-use Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Annual Total Load

(cfu/yr) AML 35.0E09 31.6E09 35.0E09 33.9E09 35.0E09 33.9E09 35.0E09 35.0E09 33.9E09 35.0E09 33.9E09 35.0E09 41.2E10

Barren 11.6E10 10.5E10 11.6E10 11.2E10 11.6E10 11.2E10 11.6E10 11.6E10 11.2E10 11.6E10 11.2E10 11.6E10 13.6E11 Comm. 16.9E10 15.3E10 16.9E10 16.4E10 16.9E10 16.4E10 16.9E10 16.9E10 16.4E10 16.9E10 16.4E10 16.9E10 19.9E11



Table A.8 Monthly, directly deposited fecal coliform loads in each reach of BUH01A04 (Reaches 33, 34).

Source Type


Annual Total Load

(cfu/yr)Human/Pet 33 94.7E10 85.5E10 94.7E10 91.6E10 94.7E10 91.6E10 94.7E10 94.7E10 91.6E10 94.7E10 91.6E10 94.7E10 11.2E12

Livestock 33 27.2E09 24.6E09 38.9E09 52.7E09 54.4E09 64.0E09 66.1E09 66.1E09 52.7E09 38.9E09 37.6E09 27.2E09 55.0E10

Wildlife 33 96.2E09 86.9E09 96.2E09 93.1E09 96.2E09 93.1E09 96.2E09 96.2E09 93.1E09 96.2E09 93.1E09 96.2E09 11.3E11




TMD

L Developm

ent

Powell R


A-9

A

PPEND

IX A

Table A.9 Existing annual loads from direct-deposition sources for the BUH01A04 (Reaches 33, 34): Source Annual Total Load (cfu/yr)beaver 27.7E08






TMD

L Developm

ent

Powell R


A-10

A

PPEND

IX A

Table A.10 Current conditions of land applied fecal coliform load for PWL01A00 by land-use(Sub-watersheds 46, 47, 48, 49, 50, 55, 56, 58, 59):

Land-use Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

Annual Total Load

(cfu/yr) Active Mining

37.1E10 33.5E10 37.1E10 35.9E10 37.1E10 35.9E10 37.1E10 37.1E10 35.9E10 37.1E10 35.9E10 37.1E10 43.7E11

AML 12.0E11 10.8E11 12.0E11 11.6E11 12.0E11 11.6E11 12.0E11 12.0E11 11.6E11 12.0E11 11.6E11 12.0E11 14.1E12 Barren 15.4E10 13.9E10 15.4E10 14.9E10 15.4E10 14.9E10 15.4E10 15.4E10 14.9E10 15.4E10 14.9E10 15.4E10 18.1E11 Comm. 46.0E10 41.6E10 46.0E10 44.5E10 46.0E10 44.5E10 46.0E10 46.0E10 44.5E10 46.0E10 44.5E10 46.0E10 54.2E11 Forest 41.1E12 37.1E12 41.1E12 39.8E12 41.1E12 39.8E12 41.1E12 41.1E12 39.8E12 41.1E12 39.8E12 41.1E12 48.4E13 LAX 48.3E10 43.6E10 63.5E10 81.0E10 83.7E10 95.7E10 98.9E10 98.9E10 81.0E10 63.5E10 61.4E10 58.0E10 87.8E11


TMD

L Developm

ent

Powell R


A-11

A

PPEND

IX A

Table A.11 Monthly, directly deposited fecal coliform loads in each reach of PWL01A00 (Reaches 46, 47, 48, 49, 50, 55, 56, 58, 59).

Source Type


Annual Total Load

(cfu/yr)Human/Pet 46 12.4E11 11.2E11 12.4E11 12.0E11 12.4E11 12.0E11 12.4E11 12.4E11 12.0E11 12.4E11 12.0E11 12.4E11 14.6E12 Livestock 46 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 46 23.5E10 21.2E10 23.5E10 22.7E10 23.5E10 22.7E10 23.5E10 23.5E10 22.7E10 23.5E10 22.7E10 23.5E10 27.6E11






Livestock 50 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 50 12.4E10 11.2E10 12.4E10 12.0E10 12.4E10 12.0E10 12.4E10 12.4E10 12.0E10 12.4E10 12.0E10 12.4E10 14.5E11



TMD

L Developm

ent

Powell R


A-12

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr)Livestock 56 18.4E09 16.6E09 26.3E09 35.6E09 36.8E09 43.2E09 44.6E09 44.6E09 35.6E09 26.3E09 25.4E09 18.4E09 37.2E10

Wildlife 56 29.3E09 26.4E09 29.3E09 28.3E09 29.3E09 28.3E09 29.3E09 29.3E09 28.3E09 29.3E09 28.3E09 29.3E09 34.4E10 Human/Pet 58 34.6E11 31.3E11 34.6E11 33.5E11 34.6E11 33.5E11 34.6E11 34.6E11 33.5E11 34.6E11 33.5E11 34.6E11 40.8E12


Human/Pet 59 55.3E11 49.9E11 55.3E11 53.5E11 55.3E11 53.5E11 55.3E11 55.3E11 53.5E11 55.3E11 53.5E11 55.3E11 65.1E12 Livestock 59 97.2E09 87.7E09 13.9E10 18.8E10 19.4E10 22.8E10 23.6E10 23.6E10 18.8E10 13.9E10 13.4E10 97.2E09 19.6E11


TMD

L Developm

ent

Powell R


A-13

A

PPEND

IX A

Table A.12 Existing annual loads from direct-deposition sources for the PWL01A00 (Reaches 46, 47, 48, 49, 50, 55, 56, 58, 59):

Source Annual Total Load (cfu/yr)Beaver 18.6E09






TMD

L Developm

ent

Powell R


A-14

A

PPEND

IX A

Table A.13 Current conditions of land applied fecal coliform load for WAL01A00 by land-use(Sub-watersheds 18, 19, 21, 23, 24, 25):

Land-use Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

Annual Total Load

(cfu/yr) Barren 14.3E10 12.9E10 14.3E10 13.9E10 14.3E10 13.9E10 14.3E10 14.3E10 13.9E10 14.3E10 13.9E10 14.3E10 16.9E11 Comm. 30.8E09 27.8E09 30.8E09 29.8E09 30.8E09 29.8E09 30.8E09 30.8E09 29.8E09 30.8E09 29.8E09 30.8E09 36.2E10



TMD

L Developm

ent

Powell R


A-15

A

PPEND

IX A

Table A.14 Monthly, directly deposited fecal coliform loads in each reach of WAL01A00 (Reaches 18, 19, 21, 23, 24, 25).

Source Type


Annual Total Load

(cfu/yr) Human/Pet 18 12.7E11 11.5E11 12.7E11 12.3E11 12.7E11 12.3E11 12.7E11 12.7E11 12.3E11 12.7E11 12.3E11 12.7E11 14.9E12 Livestock 18 14.9E09 13.5E09 21.3E09 28.9E09 29.8E09 35.0E09 36.2E09 36.2E09 28.9E09 21.3E09 20.6E09 14.9E09 30.2E10 Wildlife 18 14.0E10 12.6E10 14.0E10 13.5E10 14.0E10 13.5E10 14.0E10 14.0E10 13.5E10 14.0E10 13.5E10 14.0E10 16.4E11






TMD

L Developm

ent

Powell R


A-16

A

PPEND

IX A

Table A.15 Existing annual loads from direct-deposition sources for the WAL01A00 (Reaches 18, 19, 21, 23, 24, 25): Source Annual Total Loas (cfu/yr)Beaver 13.7E09






TMD

L Developm

ent

Powell R


A-17

A

PPEND

IX A

Table A.16 Current conditions of land applied fecal coliform load for POW03A00 by land use(Sub-watersheds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69):


Active Mining

52.6E11 47.5E11 52.6E11 50.9E11 52.6E11 50.9E11 52.6E11 52.6E11 50.9E11 52.6E11 50.9E11 52.6E11 61.9E12




TMD

L Developm

ent

Powell R


A-18

A

PPEND

IX A

Table A.17 Monthly, directly deposited fecal coliform loads in each reach of POW03A00 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69).

Source Type


Annual Total Load

(cfu/yr) Human/Pet 1 38.7E10 35.0E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 45.6E11 Livestock 1 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 1 13.8E10 12.5E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 16.3E11







TMD

L Developm

ent

Powell R


A-19

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr) Wildlife 7 37.5E10 33.9E10 37.5E10 36.3E10 37.5E10 36.3E10 37.5E10 37.5E10 36.3E10 37.5E10 36.3E10 37.5E10 44.1E11








TMD

L Developm

ent

Powell R


A-20

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr) Wildlife 30 53.7E09 48.5E09 53.7E09 52.0E09 53.7E09 52.0E09 53.7E09 53.7E09 52.0E09 53.7E09 52.0E09 53.7E09 63.3E10











Human/Pet 35 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00

Livestock 35 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00


TMD

L Developm

ent

Powell R


A-21

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr) Human/Pet 36 75.8E10 68.5E10 75.8E10 73.4E10 75.8E10 73.4E10 75.8E10 75.8E10 73.4E10 75.8E10 73.4E10 75.8E10 89.3E11















TMD

L Developm

ent

Powell R


A-22

A

PPEND

IX A

Table A.18 Existing annual loads from direct-deposition sources for the POW03A00 (Reaches 1, 2 , 3, 4, 5, 6, 7, 8, 9, 10, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 69):

Source Annual Total Load (cfu/yr)beaver 40.3E09






TMD

L Developm

ent

Powell R


A-23

A

PPEND

IX A

Table A.19 Current conditions of land applied fecal coliform load for POW02A02 by land use (Sub-watersheds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69):


Active Mining

56.3E11 50.9E11 56.3E11 54.5E11 56.3E11 54.5E11 56.3E11 56.3E11 54.5E11 56.3E11 54.5E11 56.3E11 66.3E12




TMD

L Developm

ent

Powell R


A-24

A

PPEND

IX A

Table A.20 Monthly, directly deposited fecal coliform loads in each reach of POW02A02 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69).

Source Type


Annual Total Load

(cfu/yr)Human/Pet 1 38.7E10 35.0E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 38.7E10 37.5E10 38.7E10 37.5E10 38.7E10 45.6E11 Livestock 1 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 1 13.8E10 12.5E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 13.8E10 13.4E10 13.8E10 13.4E10 13.8E10 16.3E11







TMD

L Developm

ent

Powell R


A-25

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr)Livestock 7 12.1E10 11.0E10 17.3E10 23.5E10 24.3E10 28.5E10 29.5E10 29.5E10 23.5E10 17.3E10 16.8E10 12.1E10 24.6E11 Wildlife 7 37.5E10 33.9E10 37.5E10 36.3E10 37.5E10 36.3E10 37.5E10 37.5E10 36.3E10 37.5E10 36.3E10 37.5E10 44.1E11








TMD

L Developm

ent

Powell R


A-26

A

PPEND

IX A

Source Type


Annual Total Load









TMD

L Developm

ent

Powell R


A-27

A

PPEND

IX A

Source Type


Annual Total Load









TMD

L Developm

ent

Powell R


A-28

A

PPEND

IX A

Source Type


Annual Total Load






Human/Pet 44 22.7E11 20.5E11 22.7E11 22.0E11 22.7E11 22.0E11 22.7E11 22.7E11 22.0E11 22.7E11 22.0E11 22.7E11 26.7E12 Livestock 44 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00

Wildlife 44 12.1E10 10.9E10 12.1E10 11.7E10 12.1E10 11.7E10 12.1E10 12.1E10 11.7E10 12.1E10 11.7E10 12.1E10 14.3E11 Human/Pet 45 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Livestock 45 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 45 23.0E10 20.8E10 23.0E10 22.3E10 23.0E10 22.3E10 23.0E10 23.0E10 22.3E10 23.0E10 22.3E10 23.0E10 27.1E11


TMD

L Developm

ent

Powell R


A-29

A

PPEND

IX A

Source Type


Annual Total Load

(cfu/yr)Livestock 46 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 00E00 Wildlife 46 23.5E10 21.2E10 23.5E10 22.7E10 23.5E10 22.7E10 23.5E10 23.5E10 22.7E10 23.5E10 22.7E10 23.5E10 27.6E11









TMD

L Developm

ent

Powell R


A-30

A

PPEND

IX A

Source Type


Annual Total Load






APPENDIX A A-31

Table A.21 Existing annual loads from direct-deposition sources for the POW02A02 (Reaches 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 44, 45, 46, 47, 48, 49, 50, 55, 56, 58, 59, 69):

Source Annual Total Load (cfu/yr)beaver 84.2E09







APPENDIX B B-1

APPENDIX B- SPECIAL SAMPLING

Table B. 1 Sediment metals at VADEQ monitoring station 6BBLK000.13.

Metal PEC (mg/Kg)

VA 99th Percentile (mg/Kg)

Value (mg/Kg)

ALUMINUM 4,550 ANTIMONY 5.0 ARSENIC 33 5.0 BERYLIUM 5.0 CADMIUM 4.98 1.0 CHROMIUM 111 6.3 COPPER 149 8.3 IRON 15,500 LEAD 128 6.3 MANGENESE 3,280 MERCURY 0.1 NICKEL 48.6 47.8 SELENIUM 1.0 SILVER 2.6 1.0 THALLIUM 5.0 ZINC 459 81.2

Table B. 2 Sediment metals at VADEQ monitoring station 6BLOC001.05.

Metal PEC (mg/Kg)


Value (mg/Kg)

ALUMINUM 4,800 ANTIMONY 5.0 ARSENIC 33 5.0 BERYLIUM 5.0 CADMIUM 4.98 1.0 CHROMIUM 111 8.1 COPPER 149 25.3 IRON 16,080 LEAD 128 11.3 MANGENESE 527 MERCURY 0.1 NICKEL 48.6 10.6 SELENIUM 1.0 SILVER 2.6 1.0 THALLIUM 5.0 ZINC 459 46.1


B-2 APPENDIX B

Table B. 3 Sediment metals at VADEQ monitoring station 6BPOW183.55.

Metal PEC (mg/Kg)


Value (mg/Kg)


Table B. 4 Sediment metals at VADEQ monitoring station 6BPOW197.21.

Metal PEC (mg/Kg)


Value (mg/Kg)



APPENDIX B B-3

Table B. 5 Conventional parameters collected at 11 VADEQ monitoring stations in the Powell River watershed on June 1-3, 2009).

Parameter 6BBLK000.13 6BCAL001.57 6BLOC001.05 6BPIG000.04

ALKALINITY (MG/L AS CA CO3) 153 179 250 226 AMMONIA, TOTAL (MG/L AS N) 0.04 0.04 0.04 0.04 DO_MGL 7.8 9.3 9.8 8.7 FIXED SUSPENDED SOLIDS (MG/L) 3.0 6.0 3.0 3.0

FLUORIDE, TOTAL (MG/L AS F) 0.1 0.1 0.2 0.1 HARDNESS, EDTA (MG/L AS CACO3) 780 372 294 568

NITRATE, TOTAL (MG/L AS N) 0.81 1.16 0.77 1.41 PH_SU 7.4 7.9 8.1 8.0 SULPHATE, TOTAL (MG/L AS SO4) 640 362 238 493

TDS 1,116 712 602 944 TOTAL SUSPENDED SOLIDS (MG/L) 3.0 7.0 4.0 3.0

TURBIDITY FTU 1.5 3.7 2.3 1.4 VOLATILE SUSPENDED SOLIDS (MG/L) 3.0 3.0 3.0 3.0

WTEMP_C 20.9 14.1 15.7 17.8


B-4 APPENDIX B

Table B. 5 Conventional parameters collected at 11 VADEQ monitoring stations in the Powell River watershed on June 1-3, 2009) (cont.).

Parameter 6BPLL000.27 6BPOW115.51 6BPOW179.20 6BPOW183.55

ALKALINITY (MG/L AS CA CO3) 92 152 181 167

AMMONIA, TOTAL (MG/L AS N) 0.04 0.04 0.04 0.04

DO_MGL 10.2 7.0 9.8 8.9 FIXED SUSPENDED SOLIDS (MG/L) 5.0 3.0 4.0 7.0

FLUORIDE, TOTAL (MG/L AS F) 0.1 0.1 0.1 0.1

HARDNESS, EDTA (MG/L AS CACO3) 130 222 388 424

NITRATE, TOTAL (MG/L AS N) 0.57 0.74 1.23 1.38 PH_SU 8.0 7.9 8.0 8.0 SULPHATE, TOTAL (MG/L AS SO4) 20 139 345 367

TDS 152 360 682 710 TOTAL SUSPENDED SOLIDS (MG/L) 6.0 3.0 5.0 9.0

TURBIDITY FTU 3.1 1.7 3.7 4.2 VOLATILE SUSPENDED SOLIDS (MG/L) 3.0 3.0 3.0 3.0

WTEMP_C 19.5 21.1 18.6 16.5

Table B. 5 Conventional parameters collected at 11 VADEQ monitoring stations in the Powell River watershed on June 1-3, 2009) (cont.). Parameter 6BPOW193.38 6BPOW197.21 6BRIN000.31

ALKALINITY (MG/L AS CA CO3) 124 109 207 AMMONIA, TOTAL (MG/L AS N) 0.05 0.04 0.04 DO_MGL 7.3 8.6 8.2 FIXED SUSPENDED SOLIDS (MG/L) 6.0 3.0 9.0 FLUORIDE, TOTAL (MG/L AS F) 0.1 0.1 0.2 HARDNESS, EDTA (MG/L AS CACO3) 328 270 488 NITRATE, TOTAL (MG/L AS N) 0.29 0.13 2.03 PH_SU 7.5 7.8 8.0 SULPHATE, TOTAL (MG/L AS SO4) 238 180 475 TDS 490 376 904 TOTAL SUSPENDED SOLIDS (MG/L) 7.0 3.0 11.0 TURBIDITY FTU 4.3 3.1 6.9 VOLATILE SUSPENDED SOLIDS (MG/L) 3.0 3.0 3.0

WTEMP_C 18.5 20.5 18.3

e. coli and phased benthic total maximum daily load ......daniel boone soil and water conservation...

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