land-applied wastewater effluent impacts on the edwards aquifer
DESCRIPTION
Land-Applied Wastewater Effluent Impacts on the Edwards Aquifer. by: D. Lauren Ross, Ph. D., P. E. Glenrose Engineering, Inc. 512.326.8880 glenrose.com. Acknowledgements:. City of Austin U.S. Geological Survey BS/EACD LCRA. Fragile Streams. Naturally low flow Naturally low nutrients. - PowerPoint PPT PresentationTRANSCRIPT
Land-Applied Wastewater Effluent Impactson the Edwards Aquifer
by: D. Lauren Ross, Ph. D., P. E. Glenrose Engineering, Inc. 512.326.8880glenrose.com
Acknowledgements:City of
AustinU.S.
Geological Survey
BS/EACDLCRA
Fragile Streams
Naturally low flow
Naturally low nutrients
Fragile Aquifer
Rapid FlowNo FiltrationRecharged
through both Upland and Stream Features
Texas Land Application Permits in the San Antonio
and Barton Springs Edwards Aquifer Recharge Zones
NONE
Texas Land Application Permits in the San Antonio
and Barton Springs Edwards Aquifer Contributing
Zones
67
Texas Land Application Permits
San Antonio and Barton Springs Edwards Aquifer
Contributing Zones
Barton Springs Edwards Aquifer Contributing Zone: 26
San Antonio Edwards Aquifer Contributing Zone: 41
Barton Springs
San Antonio Edwards
0
1
2
3
4
5
6
7
0
500
1,000
1,500
2,000
2,500
5.75
3.18
2,063
1,461
Total Flow (MGD)Total Irrigated Area (acres)
Tota
l Flo
w (M
GD
)
Irri
gate
d Ar
ea (a
cres
)
24 Times the TLAPed Effluent in the Barton Springs Compared to
the San Antonio Edwards Aquifer
Contributing Zones on an Area Basis
What Determines A Protective TLAP?
Effluent Treatment Technology
Effluent Treatment StandardsEffluent Storage
RequirementsIrrigation Area Requirements
Different Effluent Treatment Technologies
Activated Sludge: 44 (70%)Membrane Bioreactor: 2 (3%)Others:
Facultative LagoonSeptic TankNot Specified (2)
Widely Different Effluent Standards
Daily Average BOD and TSS Range from 5 to 30 mg/l
16 have no effluent limitsOnly 10 with nutrient limitsOnly 2 with total nitrogen
limits
Widely Different Effluent Storage Requirements
21 Systems with no storage requirement
Required Days Storage Ranges from 0.08 to 308 Days
Average for Subsurface Irrigation: 5.8 Days
Average for Surface Irrigation: 70 Days
Widely Different Effluent Irrigation Area Requirements
Application Rates Range from 0.08 to 12.20 acre-feet per acre per year
The most common rate is 4.88 acre-feet per acre per year (0.1 gal/day/sf)
Evidence of Stream Degradation
No Monitoring RequirementsNutrients are Most MobileCompounding and Confusing
Nutrient SourcesNutrients can “disappear” out of
the water column into algae growth
0.68
0.47
0.19
0.63
0.21
0.08
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Effluent-Irrigated Golf Course
Effluent Irrigated Residential
Residential on Septic
Nitr
ate
as N
itrog
en (m
g/l)
Mean
Median
Nitrate Concentration in Barton Creek Canyons Baseflow (COA, 1997)
Degradation Evidence: Belterra Subdivision
0.47
0.82
1.31
0.49 0.450.53
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Belterra Spring at
Aspen Drive
Bear Creek at Davis Property
Line
Bear Creek Riffle above Davis Pond
Bear Creek in Davis Pond
Bear Creek Pond at Bear
Creek Pass
Bear Creek Riffle at Bear
Creek Pass
Nitr
ate
(mg/
l as N
)TLAP Irrigation
Area
Degradation Evidence: Barton Creek West
Increasing Nitrate Concentrations in Scenic Bluff Springs Over Time
Degradation Evidence: West Cypress Hills
West Lick Creek Downstream from Pedernales Canyon Trail
Algae in East Lick Creek Downstream from Pedernales
Canyon Trail
Degradation Evidence: West Cypress Hills
Broken Effluent Irrigation Pipe
Degradation Evidence: West Cypress Hills
Broken Effluent Irrigation Pipe
Degradation Evidence: West Cypress Hills
Lick Creek Below Broken Effluent Irrigation Pipe
Degradation Evidence: West Cypress Hills
Algae Down Stream from Effluent Irrigation
Degradation Evidence: West Cypress Hills
0.03 0.03 0.03
0.240.09
0.56
0.91
0.070.09 0.030.13
0.62 0.59
0.190.03
0.21 0.190.05 0.03
0.38
0.74 0.67
2.87
0.24
0.70
0.30
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Lick Creek above Horse
Barn Trib: Drains Hwy 71
Horse Barn Tributary at Lick Creek
Grassy Swale Tributary to E.
Lick Creek
Seep on E. Lick Creek Right
Bank
E. Lick Creek above Cypress
Ranch Blvd
E. Lick Creek above
Detention Pond
West Tributary to Detention
Pond
Detention Pond
E. Lick Creek Downstream
from Detention
Pond
E. Lick Creek at Pedernales Canyon Trail
Nitr
ate
-N (m
g/L)
June 2007
September 2007
October 2009
TLAP Irrigation Area
TLAP NoncomplianceFailure to Monitor Soil: Only 2 of 64 TLAPs with
reported dataApplication Misinformation (Jeremiah Venture):Effluent Irrigation Proposed for Rocky SoilsFailure to Identify Karst FeaturesWater Balance Based on Western
Evapotranspiration Values
Effluent Irrigation Proposed for Rocky Soils
Failure to Identify Recharge Features
Images from Hauwert, Preliminary Phase I Assessment of the Jeremiah Ventures Site, September 25, 2009.
Failure to
Identify Recharg
e Feature
s
Misuse of Water Balance Method
Appli
cant's
Wate
r Bala
nce
TCEQ
Require
ments
TCEQ
Require
ments
with 20
07 Ra
infall
0
50
100
150
200
250
107.19
137.9187.13
60.7111.4
198.5
Required Irrigation Area (acres)Required Storage (acre-feet)
TLAP RecommendationsEliminate TLAPs on the Edwards Aquifer
Recharge Zone
TLAP RecommendationsEliminate TLAPs on the Edwards Aquifer
Recharge ZoneEstablish Consistent Effluent LimitsTotal Nitrogen: 3 milligrams per literTotal Phosphorous: 0.1 milligram per liter
TLAP RecommendationsStandardize Effluent Irrigation Requirements
TLAP RecommendationsStandardize Effluent Irrigation RequirementsStandardize Effluent Storage Requirements
TLAP RecommendationsStandardize Effluent Irrigation RequirementsStandardize Effluent Storage RequirementsEliminate Leaching Allowance
TLAP RecommendationsStandardize Effluent Irrigation RequirementsStandardize Effluent Storage RequirementsEliminate Leaching AllowanceRequire Soil, Spring, Stream, and Well
Monitoring with Re-permitting Triggers
TLAP RecommendationsStandardize Effluent Irrigation RequirementsStandardize Effluent Storage RequirementsEliminate Leaching AllowanceRequire Soil, Spring, Stream, and Well
Monitoring with Re-permitting TriggersRequire Soil Monitoring and Automatic
Response to Saturated or Frozen Soil Conditions