Using ASR as a Component of

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Using ASR as a Component of Managing Water Supply
Growth, City of Dallas, OR
Presented By
Phil Brown, Golder Associates
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Presentation Outline

• What is ASR?
• Why Use ASR?
• Benefits to City of Dallas

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What is ASR?

• 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)

Be Careful What You Ask For
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Aquifer Storage and Recovery

• Water is Treated to Applicable Standards
• Stored in the Subsurface
• Recovered for Later Use

Water Typically Stored and Recovered from the
Same Well
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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

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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

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Technical Issues

• Source Water Availability
• Source Water Quality
• Aquifer Storage Capacity
• Geochemical Compatibility
• Recovery Efficiency where native groundwater
  quality is poor

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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

Dallas
Rickreall Creek
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City of Dallas 2007 Water System

• 5643 Connections
• 81 new

• 842 MG Delivered

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City of Dallas Demand Profile
3 to 4 MGD Summer Average
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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

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Storage Options

• Flashboards at Mercer Reservoir to Create an
  Additional 170 AF
• ASR
• Construct New Reservoir
• Off-Stream Storage
• Develop Regional Supply

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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

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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

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Technical Challenges for Dallas

• 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

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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

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3rd Year, Winter 2007/2008
2006/2007

• Well performance has improved, less buildup
• Suggests higher density saline water is being
  displaced
• 50 MG Target Storage Volume

2007/2008
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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 Fresh-Water Storage Zone
  how much?
• 1 MGD 25 summer demand
• 120 MG 14 annual volume

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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

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Other Benefits
Rickreall Creek

• ASR costs do not require rate increase
• Increased supply supports growth

WTP and ASR Site
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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

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Questions?

• Thank you for your time!