The Dockum Aquifer, West Texas Robert G. Bradley, P.G. Texas Water Development Board.
© 2009 Malcolm Pirnie, Inc. All Rights Reserved An Assessment of Aquifer Storage and Recovery in...
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Transcript of © 2009 Malcolm Pirnie, Inc. All Rights Reserved An Assessment of Aquifer Storage and Recovery in...
© 2009 Malcolm Pirnie, Inc. All Rights Reserved
An Assessment of Aquifer Storage and Recovery in Texas
66th Annual Convention
Texas Water Conservation AssociationMarch 4, 2010
Fred Blumberg
Senior Associate
Malcolm Pirnie, Inc.
ASR is defined as:
“…the storage of water in a suitable aquifer … during times when water is available, and recovery of the water … during times when it is needed.”
- David G. Pyne, P.E.ASR Systems, LLC
Gainesville, FL
Native
Ground
Water
Native
Ground
Water
Confining Layer Confining Layer
Confining Layer
BufferZone
BufferZone
StoredWater
StoredWater
Target Storage Volume
ASR WellASR Well
Over 22 ASR Applications
Storage• Seasonal/Peaking• Long-Term• Emergency
Water Quality • DBP Reduction• Nutrient Reduction• Temperature Control
Reclaimed Water Storage / Reuse
Defer Expansions• Maintain distribution
system flow / pressure• Peaking• Irrigation water supply
Aquifer Protection• Reduce drawdown• Maintain springflow• Pollution plume cutoff
Sources and Storage Zones
Water sources:• Potable water• Reclaimed water--treated • Seasonally-available stormwater--treated• Groundwater from overlying, underlying or nearby
aquifers Storage zones
• Fresh, brackish and saline aquifers• Confined, semi-confined and unconfined aquifers• Sand, clayey sand, gravel, sandstone, limestone,
dolomite, basalt, conglomerates, glacial deposits• Vertically “stacked” storage zones
Minimal evaporation
Fewer environmental impacts
Competitive cost (capital cost ≈ $1.25/gallon/day of capacity)
Flexibility--incremental well addition
ASR Advantages
Supplementation of other water supply strategies
Broad range of applications and geographic settings
ASR Operating Ranges
Well depths• 30 to 2700 feet
Storage interval thickness• 20 to 400 feet
Storage zone TDS• 30 mg/l to 39,000 mg/l
Storage Volumes• 100 AF to >270,000 AF
Bubble radius less than 1000 ft Individual wells up to 8 MGD Wellfield capacity up to 157 MGD
Calleguas MWD, Thousand Oaks, California
ASR Well
ASR Considerations/Constraints
Recharge water quality and pretreatment requirements
Water quality in receiving aquifer (e.g., TDS, Fe, Mn, pH)
Land availability and cost
Recovery efficiency
Public understanding
Legal / regulatory framework
ASR Development Phases
Feasibility Assessment & Conceptual Design• Water supply and demand—source, reliability, variability
• Hydrogeology and modeling
• Site selection, regulations and conceptual design
• Target storage volume (TSV)
• Cost estimate
• Test program outline
Field Investigations & Test Program• Exploratory well
• Baseline and cycling tests
• Data collection
Recharge Facilities Expansion• Well spacing and design
• Construction and O&M
TWDB Priority Water Research Topics Project
TWDB funding for topics of recognized importance
ASR Project Objectives:
Review the current state of ASR implementation
Evaluate technical and legal issues limiting broader application of ASR in Texas
Provide education on ASR and its potential applications as a water resource tool in Texas
Peer review by USBuRec
Study Team
Malcolm Pirnie, Inc. ASR Systems, LLC Edmond McCarthy, Jr., JD Existing ASR Utilities in Texas
San Antonio Water System (SAWS)El Paso Water Utilities (EPWU)City of Kerrville
TWDB ASR Research Project
Legal White Paper --- presenting public policy perspectives
Interviews / Site Visits with 3 Participating Utilities Kerrville
SAWS
EPWU
Survey of Other Utilities
Review of literature and US/global practices
Presentations and guidance for implementation
San Antonio Water System
OBJECTIVES: Began as seasonal storage reserve; transitioned to long-term storage
3rd largest ASR project in U.S.
29 ASR wells
Capacity: 60 mgd
Source: Groundwater from the Edwards Aquifer
Storage zone: Carrizo Aquifer
Current Volume: >70,000 AFOperation began in
2004
Twin Oaks ASR Facility
Carrizo Aquifer
Confined aquifer
pH 5.5
Elevated Fe/Mn and hydrogen sulfide
Project includes 3 local Carrizo wells
Water treatment available to remove Fe/Mn, adjust pH, and provide disinfection
To date, only disinfection has been needed for recovered ASR water
City of Kerrville
OBJECTIVES: Storage for drought management and peaking
2nd ASR project in Texas (1995)
2 ASR wells (3rd in development)
Capacity: 2.65 mgd
Source: Treated surface water from Guadalupe River
Storage zone: Lower Trinity Aquifer
Max Volume to Date: 2,100 AF
El Paso Water Utilities
OBJECTIVES: Restore GW levels; store reclaimed water; improve WQ; supply peaking water
1st ASR project in Texas
4 ASR wells and 4 basins
Capacity: ~10 mgd
Source: Treated wastewater from Fred Hervey WRP
Storage zone: Hueco Bolson Aquifer
Summary
Component EPWU
(10 mgd)
Kerrville
(2.65 mgd)
SAWS
(60 mgd)
Date 1985 1995 2004Source Water Treated
WastewaterTreated River Water
Groundwater
Storage 300-835 feet
Hueco Bolson
495-613 feet
Lower Trinity
400-600 feet
CarrizoIssues Original well
design Customers for
reclaimed water
Litigation during permitting
Lack of source water
Single pipeline Distribution
system limitations
Expansion Plans
Expanding FHWRP Constructing 4th spreading basin
Adding 3rd ASR well
WTP expansion in Regional Plan
Part of 50-year Management Plan
Evaluating TSV
ASR Seminar
Fall 2010 San Antonio, TX Participants
Texas Water Development BoardU.S. Bureau of ReclamationMalcolm PirnieASR Systems