Transcript No Slide Title

Using ASR as a Component of
Managing Water Supply & Growth,
City of Dallas, OR
Presented By:
Phil Brown, Golder Associates
Presentation Outline
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What is ASR?
Why Use ASR?
Benefits to City of Dallas
What is ASR?
Be
Careful
What
You Ask
For
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Alkali Silica Reaction (ASR) ("concrete cancer”)
Asian Soybean Rust (ASR)
Automotive Shredder Residue (ASR) (or "fluff“)
Americans for Secure Retirement (ASR)
Architects for Social Responsibility (ASR)
Artificial Surf Reefs (ASR)
Australian Seabird Rescue (ASR)
Answer Seizure Ratio (ASR) (website operation)
Annual Security Report (ASR) (SEC requirement)
Articular Surface Replacement' (ASR) (new hip joint)
Acceleration Slip Regulation (ASR)
Answer Supervision Ratio (ASR) (telemarketing)
American Systems Registrar (ASR) (ISO 9000)
Artificial Silicon Retina (ASR) (microchip implants)
Accredited Seller Representative (ASR®) (real estate)
Aquifer Storage and Recovery
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Water is Treated to
Applicable Standards
Stored in the
Subsurface
Recovered for Later
Use
Water Typically Stored and Recovered from the Same
Well
Why Use ASR?
• New Supply Sources are Limited
– Minimum instream flow
– Over-allocation
– Conjunctive use policies
• Water can be available during winter
months: high-flow/low-demand
• Subsurface storage less expensive
• WTP Efficiency
What Does ASR Do?
• Re-distributes surface water
supply profile
• Expands capacity through
increased storage
• Provides emergency/second
source
• Makes existing infrastructure
and new construction more
efficient
Technical Issues
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Source Water Availability
Source Water Quality
Aquifer Storage Capacity
Geochemical Compatibility
Recovery Efficiency – where
native groundwater quality is
poor
City of Dallas Water Supply
 Mercer Reservoir
Stores Water on
Rickreall Creek
(designed for 1550 AF)
 10 cfs summer releases
from Mercer Reservoir
 5.9 cfs Diverted to WTP
During Summer Months
Rickreall
Creek
Dallas
City of Dallas 2007 Water System
• 842 MG Delivered
• 5643 Connections
• 81 new
City of Dallas Demand Profile
3 to 4 MGD
Summer Average
Water Supply Situation: Decreasing Storage
Capacity and Increasing Demand
Mercer Reservoir loses 10
AF/year due to sedimentation
~1% annually
Approx. 500AF lost since 1973
Growth is increasing demand
Additional supply required by
2010
Storage Options:
 Flashboards at Mercer
Reservoir to Create an
Additional 170 AF
 ASR
 Construct New Reservoir
 Off-Stream Storage
 Develop Regional Supply
Storage Plan:
 Install Flashboards at Mercer
Reservoir
 Implement an ASR system
designed to recover 1 MGD
during peak demand periods
 These actions will extend
system capacity by 10 years
ASR Project Overview
2003: Completed ASR
Feasibility Studies
2004: Drilled and tested the
ASR test well (ASR No. 1)
2005: Design/Construction
of ASR No. 1
Technical Challenges for Dallas
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Low permeability fractured rock
Aquifer (?) not well defined
Fresh water shallow - Saline water deep
Need to develop fresh storage zone
Advective dispersion, density driven mixing
Recovery efficiency starts low, then
improves
RE% = (VR / VS) X 100
ASR Project Overview
2006:
Received ASR testing
permit
Facility construction
1st year of testing
 6 short cycles
Winter 2006/2007:
2nd year of pilot testing
 1st operational-scale cycle
3rd Year, Winter 2007/2008
• Well performance
has improved,
less buildup
• Suggests higher
density saline
water is being
displaced
• 50 MG Target
Storage Volume
2006/2007
2007/2008
ASR Pilot Testing Results To-Date
 Single-Well System: 0.35 MGD
and store 50+ MG/year,
 3-well system: 1+ MGD and
store 120 MG/year
 Aquifer can support ASR,
though at limited rates/volumes
 Project Will Develop FreshWater Storage Zone: how
much?
1 MGD = 25% summer demand
120 MG = 14% annual volume
Flow Benefit to Rickreall Creek
 Excess capacity at WTP
allows the City to manage
flows in Rickreall Creek
 Higher flows:
 Increase velocity
Limit warming
Increase DO
Other Benefits
ASR costs do not
require rate increase
Increased supply
supports growth
Rickreall Creek
WTP and ASR Site
The City of Dallas ASR Program Will
Benefit Rate Payers
Result in a Cost Effective
Source Expansion Option
Provide Watershed-Scale
Benefit Rickreall Creek,
and Downstream Users
Questions?
Thank you for your time!