Transcript Aquifer Storage and Recovery

An Assessment of
Aquifer Storage and
Recovery in Texas
66th Annual Convention
Texas Water Conservation Association
March 4, 2010
Fred Blumberg
Senior Associate
Malcolm Pirnie, Inc.
© 2009 Malcolm Pirnie, Inc. All Rights Reserved
Outline
Introduction to ASR
TWDB Priority Research Project
Case Studies from Texas
Summary
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
Recharge Alternatives Include…
 Basins, channels
 Vadose zone
wells
 Injection wells
ASR Well
Confining Layer
Confining Layer
Native
Ground
Water
Native
Buffer
Zone
Stored
Water
Stored
Water
Buffer
Zone
Ground
Water
Target Storage Volume
Confining Layer
Over 22 ASR Applications
Storage
Water Quality
• Seasonal/Peaking
• Long-Term
• Emergency
• DBP Reduction
• Nutrient Reduction
• Temperature Control
Defer Expansions
•Maintain distribution
system flow / pressure
•Peaking
•Irrigation water supply
Reclaimed Water
Storage / Reuse
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
ASR Advantages
 Minimal evaporation
 Fewer environmental impacts
 Competitive cost (capital cost ≈
$1.25/gallon/day of capacity)
 Flexibility--incremental well
addition
 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)
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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
Operational ASR Wellfields (~ 95 in 2009)
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
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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 AF
Operation 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
EPWU—Fred Hervey WRP
Summary
Component
Date
Source Water
Storage
Issues
Expansion
Plans
EPWU
Kerrville
SAWS
(10 mgd)
(2.65 mgd)
(60 mgd)
1985
Treated
Wastewater
300-835 feet
1995
Treated River
Water
495-613 feet
2004
Groundwater
Hueco Bolson
 Original well
design
Lower Trinity
 Litigation
during
permitting
Carrizo
 Single pipeline
 Customers for
reclaimed
water
Expanding
FHWRP
Constructing 4th
spreading basin
 Lack of source
water
Adding 3rd ASR
well
WTP expansion
in Regional Plan
400-600 feet
 Distribution
system
limitations
Part of 50-year
Management Plan
Evaluating TSV
Initial Utility Survey—Why ASR Has Not
Been Pursued
ASR Seminar
 Fall 2010
 San Antonio, TX
 Participants
Texas Water Development Board
U.S. Bureau of Reclamation
Malcolm Pirnie
ASR Systems
Questions
Fred M. Blumberg
Senior Associate
Malcolm Pirnie, Inc.
512-370-3865
[email protected]