Meeting Minutes

Wednesday, March 11, 2015 at 1:00 PM at Littleton/Englewood WWTP

2900 S. Platte River Drive, Englewood

In Attendance: Tim Grotheer Centennial WSD Martha Hahn PCWRA Amy Woodis MWRD Shelley Stanley Northglenn Jill Piatt Kemper Aurora Dennis Stowe L/E WWTP Julie Tinetti Plum Creek Nancy Keller Pueblo Lauren Lundavist ASCE Report Card Colleen Young Greeley Jim Edwards ERWSD Bobby Anastasov Aurora Water Barbara Biggs CDM Smith Sarah Reeves Brown & Caldwell Clifton Bell Brown & Caldwell Ann Marie Doerhoff ASCE Report Card Jane Clary Eagle River JP Ferraro CWWUC Jim Dorsch MWRD Phone-In Participants: Dave Akers Self Ginny Johnson Colorado Springs Drew Ackerman Jessica DiToro Karen Behne Niwot Bill Veydovec

Presentations

1. Metro's Integrated Plan- Amy Woodis (See slides below)

2. Regulation 85 Data Gap Analysis Report* - Jane Clary, Wright Water Engineers and Jill Piatt-Kemper

*Determining Approximate N & P Contributions to State Waters Due to Discharges from Municipal Storm Sewer Systems. (See slides below)

3. Updates:

Barb Biggs reported on the Water Utility Council:

· Fees and regs.

Jill Piatt Kemper gave an update on Stormwater:

· Fee bill.

· Stabilization and water rights.

4. Open Discussion

· Dave Akers discussed nitrates as related to basic standards.

· Population increase and the burden of increasing regulations.

· What to discuss in April’s meeting with Pat Pfaltzgraft?

o Give him good examples of why things are not working.

o Discuss case studies not related to the June hearing.

· Tim and Martha will collaborate to create a presentation for Pat.

Adjourned at 3:00 pm

Next meeting: Wednesday, April 8, 2015, with Pat Pfaltzgraft- State Water Quality Control

Director

What Is an Integrated Plan? Reasons for Development Benefits Approach and Structure Next Steps

South Secondary aeration basins, October 2014 2

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Tool developed by the U.S. Environmental Protection Agency to address costly compliance-related issues

Integrated Planning allows agencies and municipalities to balance Clean Water Act requirements in a manner that addresses the most pressing issues first

The Framework encourages: S The use of innovative technologies S An adaptive management approach S Stakeholder input

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To present a well-developed and comprehensive regulatory master plan for Metro District facilities

S Based on current and future CWA requirements

S Takes a watershed approach (includes modeling for other dischargers)

S Implementation is primarily through permits

Reasons RWHTF outfalls 6

Long-term strategy to reduce nutrients (phosphorus and nitrogen) within the watershed

S Includes RWHTF upgrades and NTP startup

S Also includes other Segment 15 dischargers as well as controls of non-point sources

Reasons

Barr Lake

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Support startup of the NTP

S NTP will require a 90-day compliance schedule

S Integrated Plan will provide an opportunity to include additional background information related to proposed compliance schedule requests

Reasons Rendering of Phase 1 facilities

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The Integrated Planning approach balances treatment priorities with costs and associated water quality improvements

Based on adaptive management principles (“learning by doing”)

10 Benefits

Process encourages agreement from stakeholders on water quality priorities within the watershed

Cooperative efforts can make cost-effective improvements using innovative technologies and approaches

Increased opportunities to secure non-point source funding for watershed projects

Milton Reservoir in winter 11 Benefits

Since DRCOG de-designated itself as the Denver area Planning Agency, the Water Quality Control Division has been the default Clean Water Act section 208 agency

The WQCD is supportive of efforts to re-establish a Planning Agency for the Denver metropolitan area

The Integrated Plan is a possible “first step” toward that goal

South Platte River confluence with Clear Creek

12 Benefits

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1. Infrastructure and Watershed Protection Activities

2. Comprehensive Planning Activities

3. Water Quality Monitoring and Modeling Activities

Approach/ Structure

Integrated Plan

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Total phosphorus reductions

S Regulation No. 85 (short-term)

S Barr Lake-Milton Reservoir Total Maximum Daily Load requirements (longer-term)

Total nitrogen reductions

S Regulation No. 85 (short-term) S To make progress toward

Regulation No. 31 interim values

Anticipated permit limits for TP and TN

Approach/ Structure 15

Less urgent example

S Segment 15 temperature (RWHTF Discharger-Specific Variance)

Longer-term example

S Development of site-specific nutrient standards

In-stream mixing structure in the South Platte River

Approach/ Structure 16

Element 1 Water Quality, Human Health,

and Regulatory Issues S Current parameters of interest S Water quality attainment status issues S Implementation issues associated

with Barr-Milton TMDL S Anticipated future water quality

challenges

Barr Lake

Approach/ Structure 17

Element 2 Wastewater and Stormwater

Characterization and Performance S RWHTF treatment processes S NTP treatment processes S Water quality monitoring program S South Platte Water Quality Model-

related activities

NTP, August 2014 Approach/ Structure 18

Element 3 Public, Stakeholder, and

Regulatory Agency Involvement S Regulatory input (EPA and WQCD) S Watershed and stakeholder groups

§ Barr-Milton Watershed Association § Water Quality Forum

S Outreach associated with the South Platte Water Quality Model § Brighton § South Adams County W&S § Platteville § Fort Lupton

Monitoring Milton Reservoir Approach/

Structure 19

Element 4 Planning/Implementation Approaches to Meet Identified CWA Requirements

S Implementation strategies and schedules S Balancing of priorities and flexibilities S CWA obligations and costs S Expected effects on water quality of

identified activities § Load reductions § Standards attainment or improvement § Possible other environmental

consequences Struvite accumulation

Approach/ Structure 20

Element 5 Measuring Success

S Identification of appropriate metrics to evaluate improvements in water quality

S Develop schedule for future updates to the Integrated Plan

S Implementation is consistent with EPA’s Integrated Planning Approach Framework

Approach/ Structure

Johnny darter and Iowa darter

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Element 6 Improvements to the Plan

S Implementation uses an adaptive management strategy

S All appropriate alternatives are being considered through District planning efforts

S The South Platte Water Quality Model is kept up to date

S Input from stakeholders is received and concerns are addressed

Approach/ Structure

Planned tertiary treatment facilities at the RWHTF

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Next Steps

Jan 2015

Presentation to EPA Region 8

and WQCD staff

Feb 2015

Draft IP review by Vranesh &

Raisch

Mar 2015

Draft IP internal review;

Draft IP review by Barnes & Thornburg

Presentation to

Colorado Wastewater Utility Council

May 2015

Presentation to Water Quality

Forum

TBD

Revised IP review by EPA and WQCD

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Next Presentation

Estimating Nutrient Loads in Urban Runoff under Colorado’s Regulation 85

Consultant Team: Jane Clary and Andrew Earles, P.E., Ph.D., Wright Water Engineers, Inc.

Scott Struck, Ph.D., Geosyntec Consultants Robert Pitt, P.E., Ph.D., University of Alabama

Larry Roesner, P.E., Ph.D., Colorado State University

Project Sponsors: Urban Drainage and Flood Control District and Colorado Stormwater Council

Presentation by: Jill Piatt-Kemper, City of Aurora and Jane Clary, Wright Water Engineers, Inc.

Overview

• Background: Colorado’s Nutrient Regulations 85 and 31

• MS4 Requirement: “Data Gap Analysis” • Project Approach

– Colorado Data – National Data—National Stormwater Quality Database

(NSQD—Pitt) • Findings • Conclusions—what do we know about nutrients

in urban runoff in Colorado?

Colorado’s Nutrient Regulations • Regulation 31—relates to instream standards

– Adds criteria for total phosphorus, total nitrogen, chlorophyll-a

– Interim criteria—10-year window for most streams • Regulation 85—relates to discharge permits

– Requirements for municipal WWTP and certain industrial discharges:

• Numeric effluent limits (TIN & TP) • Instream monitoring

– Requirements for MS4s: • Public education and outreach • Pollution prevention/good housekeeping for municipal operations • “Data gap analysis” for MS4 stormwater discharges

– Also discusses non-point sources

“Discharge Assessment Data Report” (Due to Division by October 31, 2014)

• “Identify information that exists and the need for additional monitoring to be conducted in the future to determine the approximate nitrogen and phosphorus contribution to state waters due to discharges from MS4.”

• “Document the availability of existing data, and [provide] a “Gap Analysis” that identifies the need for additional information (e.g., monitoring data or studies), in accordance with the requirements of [the regulation].”

The Big Picture is Nutrient Loads

• Nutrient Concentration x Flow Volume = Load

• The data gap question focuses on the concentration component of load estimation.

• However, hydrology (rainfall-runoff relationship) is the big difference by land uses and for different parts of the state.

• Methods for runoff volume calculations are well-documented by UDFCD and others.

Reg. 85 Load Estimation Approaches Allowed in Data Gap Report

• Monitoring data from the MS4 discharge or downstream waters

• Monitoring data from other entities

• Land-use based models • Land-use based data from

literature

Approach Selected for Data Gap Report

• Colorado EMC data for urban stormwater runoff • Primary Data Sources

– DRURP (1980’s) – Phase 1 permit monitoring (1990’s) – UDFCD BMP monitoring (inflow data) – Other BMP monitoring (ACWWA, Grant Ranch) – CSU/City of Fort Collins – CDOT Permit-required monitoring

• Supplementary Data – City and County of Denver outfall monitoring (grabs)

• Comparative analysis of Colorado vs. national data

General Distribution of Nutrient Monitoring EMCs in Colorado Relative to Population

Statistical Methods • Basic descriptive

statistics • Boxplots • Time-series plots • Cumulative frequency

distribution • Normal probability

plots • Hypothesis testing

– Kruskal-Wallis – Mann-Whitney – Dunn’s Procedure

• Spearman correlation analysis & scatter plot matrices

Supplemental Comparative Analysis: NSQD v.3 Runoff Characterization Data

by U.S. EPA Rain Zone

KEY FINDINGS FOR TOTAL PHOSPHORUS

Colorado Total Phosphorus (mg/L)in Runoff

• Residential significantly higher than other urban land uses. • No significant difference among other urban land uses

(COM-HWY-IND). • See report for 95% confidence intervals for median values.

Land Use # Min Max 25th % Median 75th % Mean COV

COM 277 0.01 6.30 0.12 0.22 0.41 0.36 1.47 HWY 25 0.07 2.60 0.15 0.28 0.42 0.39 1.25 IND 39 0.05 1.30 0.16 0.25 0.43 0.35 0.81

OPEN 7 0.21 0.66 0.26 0.41 0.54 0.41 0.39 RES 254 0.07 2.71 0.29 0.46 0.72 0.56 0.69

COM-HWY-IND 341 0.01 6.30 0.12 0.23 0.42 0.36 1.39

Colorado TP Boxplots by Land Use

For general frame of reference only: • WWTP limit for existing facilities = 1.0 mg/L • Warmwater “interim value” = 0.17 mg/L

Colorado TP Boxplots by Land Use Groups

Cumulative Frequency Distributions TP (mg/L) by Land Use

Comparison CO TP to NSQD Data for EPA Rain Zones

(Kruskal-Wallis/Dunn’s Procedure)

Higher/Lower/NSD = indicates whether Colorado’s TP results are higher, lower or not significantly different statistically from another other rain zone; (#) = number of samples in data set

Colorado TP Data vs. NSQD Data

Key Finding from Colorado vs. National Comparison for TP

• Mean and median TP for each Colorado land use are within the range of mean and median TP for other Rain Zones.

• Colorado total phosphorus concentrations are neither extremely high nor low compared to what was found in other parts of the country.

• Rain Zone 4, the Lower Mississippi Valley is most similar to Colorado. Data sets are from Houston, Texas (60%), Kansas City (30%) Memphis, TN (10%).

KEY FINDINGS FOR TOTAL NITROGEN

Colorado Total Nitrogen (mg/L) in Runoff Land Use # Min Max 25th % Median 75th % Mean COV

COM 168 0.54 16.63 2.01 2.79 3.88 3.45 0.71 HWY 9 1.30 6.10 2.30 3.60 5.50 3.78 0.45 IND 23 1.20 8.70 2.15 3.60 4.44 3.56 0.49

OPEN 7 1.49 6.12 2.08 3.76 4.14 3.40 0.44 RES 191 0.51 22.77 2.83 4.19 6.38 5.06 0.64

COM-IND 191 0.54 16.63 2.01 2.84 3.93 3.47 0.69 • Residential significantly higher than most urban land uses. • No significant difference between commercial & industrial

land uses. • See report for 95% confidence intervals for median values.

Colorado TN Boxplots

For general frame of reference only: • WWTP limit = 15 mg/L (existing facilities) & 7 mg/L (new) • Warmwater “interim value” = 2.01 mg/L

Colorado TN Boxplots by Land Use Groups

Cumulative Frequency Distributions TN (mg/L) by Land Use

Comparison CO TN to EPA Rain Zones (Kruskal-Wallis/Dunn’s Procedure)

Higher/Lower/NSD = indicates whether Colorado’s TP results are higher, lower or not significantly different statistically from another other rain zone; (#) = number of samples in data set

• Colorado’s mean and median nitrogen concentrations are generally higher than in other Rain Zones, so use of Colorado data is preferred for estimating TN loads.

• Less national data available for TN, relative to TP. • Ongoing atmospheric N deposition studies may

be helpful in explaining this finding (but not explored in this report).

• West Slope data could potentially be supplemented by Rain Zone 6 data; analyses by Bochis (2010) focused on TKN.

Key Finding from Colorado vs. National Comparison for TN

TSS, TP, TN Relationships

• Open Space: TSS-TP strongly correlated.

• Com: TSS-TN-TP correlated

• Ind: TP-TN correlated • Hwy: not fully

evaluated

EMCs…What About Nutrient Loads?

• To estimate nutrient loads from urban land uses: üprecipitation data ü runoff volume calculations ünutrient EMC data

• For runoff volume calculations: – drainage area – land use – imperviousness – soil type

• Water Quality Capture Optimization and Statistics Model (WQ-COSM) (UWRI 2011)

Example Spreadsheet Approach Based on WQ-COSM

Effect of Precipitation on

Annual Loads

Mesa County

Denver

Colorado

US

Colorado

US

Overall Conclusion • A significant EMC-based urban runoff data set is available to

characterize nutrient loads in urban runoff in Colorado. • Data Report provides statistical characterization of TP & TN

concentrations by land use for this purpose. • Additional monitoring for purposes of general

characterization of nutrients in urban runoff in Colorado is not necessary to meet requirements of Regulation 85.

• However, in watersheds where nutrient impairments may be identified in the future and urban stormwater runoff is a likely contributor, then targeted monitoring to identify watershed-specific nutrient sources may be beneficial to help prioritize selection and placement of BMPs.

Other Specific Findings • Colorado nutrient EMC data set:

– TP Over 600 data points – TN nearly 400 data points – Represents most urban land uses – Residential and commercial have particularly robust data

• Median TP for EMCs by land use in Colorado ranges from 0.22 to 0.45 mg/L – TP in residential runoff is statistically higher than

commercial, industrial and highway land uses. • Median TN for EMCs by land use in Colorado ranges

from 2.79 to 4.19 mg/L – TN in residential runoff is statistically higher than

commercial and industrial land uses.

Findings (cont.) • Median TN & TP in runoff by land use are all

higher than interim instream water quality values—including runoff from natural areas.

• Median TN & TP in runoff by land use are all lower than the Reg. 85 WWTP discharge limits.

• Colorado TP is within ranges observed in other EPA Rain Zones.

• Colorado TN tends to be higher than ranges observed in other EPA Rain Zones.

• Rain Zone 6 (Southwest) may be useful for supplementing western Colorado data set.

Wrap-Up “The division has completed a review of the report and has determined that the report is complete and contains the information required by the regulation. The division would like to thank all participating MS4 permittees, the Colorado Stormwater Council, and Urban Drainage and Flood Control District for the excellent effort in developing a report that provides clear and meaningful information. The information in the report will be a valuable resource for future decision making by the division, the Water Quality Control Commission, the report participants, and other water quality stakeholders in Colorado.” —Nathan Moore, Water Quality Control Division, Letter to MS4 Permittees, January 5, 2015

Questions?

Jill Piatt-Kemper, City of Aurora jpiatt@auroragov.org

Jane Clary, Wright Water Engineers

clary@wrightwater.com