Aquifer Storage and Recovery: An Overview

Transcription

1 Aquifer Storage and Recovery: An Overview Prepared for: PNWS AWWA Kennewick, WA May 2017 Prepared by: Phil Brown RG, LHg May 2017

2 History of ASR in the US 1940s/1950: Early well recharge studies (USGS) in California, Washington, Oregon, Texas concerns regarding protection of water supplies during WWII 1969: First US system in Wildwood, New Jersey 1970s: ASR in California, New Jersey, Florida, seawater intrusion and aquifer management Following 1970s/1980s droughts, US Bureau of Reclamation Groundwater Demonstration Program Today: A variety of state-promulgated regulations

3 United States Development 2 Bloetscher, 2014

4 Where Bloetscher,

5 ASR: What Water injected into an aquifer through a well That water is recovered from the same (or nearby) well or wells Type project: treated drinking water 4

6 ASR: What Typical Project: Municipal Drinking Water Well Conversion 1 to 3 wells Other types: State-sponsored Agricultural Eco-enhancement Larger Scale 5

7 When Recharge: When water is available typically winter Storage: zero time to banking Recovery: When it s needed typically summer 6

8 Why Redistribute Seasonal Availability Instream Flow Rules Summer Supplies Can t Support Increasing Demand New Summer Rights Unavailable Maximization of Storage Multi-year Storage ( Water Banking ) Aquifer Sustainability Drought and Disaster Protection Reservoir Replacement Maximization of Treatment Plant Capacity Shave Peak Treatment Volume Utilize Winter Water Rights (Qa/Qi) Defer or Optimize Plant Expansion Economic Benefits

9 Why Typically much less cost than alternatives. ASR capital cost range from $500K (utilizing existing wells) to $2MM - $4MM for new wells, studies, permitting, construction, and pilot testing activities. Wells range from 0.5 to 3 MGD each, storing up to 500 MG (1500 AF) per year. ASR operating costs average about $20K per year per MGD recovery capacity, within a typical range of +/- $20K Cost is not directly proportional to storage volume, though reservoirs are Success is not defined by storage volume

10 ASR: Why Million Gal. Stored TANK 10 ASR WELL $M

11 Nonpotable ASR Uses Nonpotable uses Industrial Irrigation Saltwater Intrusion Habitat Benefits Flow Temperature Various sources Surface water Groundwater Treated Effluent Stormwater

12 Development Phase I - Feasibility Study Hydrogeologic Feasibility Study (characterization) Drill/test/sample Pilot Test Workplan ASR Permitting (state-specific) UIC Registration Can inject prior to Phase II Phase II Design and Construction Wellhead piping, controls, wellhouse Detention/disposal facilities Phase III - Test Program Phase IV Permit or System Expansion Typically 2 to 3 years from FS to operationalscale recovery

13 ASR: How Engineering Wellhead Design Recharge Control Integration with Distribution System Back-flushing and Discharge to Waste

14 ASR Well Conversion

15 ASR Engineering Wellhead Design: Recharge Loop Variable recharge rates? Variable discharge rates? Bi-directional metering 1-way air-vent Access tubing (2) Sealed pedestal Discharge to waste Line-flushing Chlorination and De-chlorination Recharge Control

16 ASR Engineering: Recharge Control Recharge should occur under pressure to avoid free cascade of water in the well casing. Sometimes VT bowl/impeller is sufficient For a significant drop and/or limited system pressure, a downhole flow control valve is required. DFCV can be used to vary recharge rate according to daily demand fluctuations Adds $50 to $100K to capital costs

17 ASR: Issues Direct Prohibition (WI, SC) No Regulations, or Restrictive Regulations Anti-degradation and DBPs Clogging, Biofouling, O&M Disposal Hydrogeology: Not Favorable Everywhere Geochemical Compatibility and Recovery Efficiency Ecological Flows 16

18 17 Questions?