City of Yakima ASR: Supplying Municipal Demand in the Face of Climate Change David Brown Water/Irrigation Manager City of Yakima AWRA National Conference - November 6, 2017
City of Yakima Location & Water Supply Naches Water Treatment Plant (25 mgd / 40 cfs, ~15,000 afy) Main Supply Groundwater Wells (~14 mgd) Backup (3-5 days at peak demand)
City of Yakima Water Supply Responsibilities PEAK DEMAND = SUPPLY (25 mgd) EMERGENCY GROUNDWATER BACKUP (14 MGD) PLANNING How to meet: Drought, climate change Possible curtailment of using water rights Interruption of supply (maintenance, contamination) Norse Peak Fire Growth
Climate Change - Drought Gordon King, Yakima Herald Republic
Drought/Pro-Rationing DROUGHT 14 times/45 years Most of City s water rights subject to prorationing 2015 was a good example of how we see the future Rain and little snow pack 44% proration Started using reservoirs in early April Next years?
Groundwater Issues Most groundwater rights are post-1905 (i.e., Junior) Now groundwater might be at risk for cut off in drought year? Groundwater aquifer levels dropping (e.g., >60 feet at Kissel) City needs existing wells AND more for the 4 Rs (reliable, redundancy, resilience & robustness). City can t continue to grow with water subject to curtailment No new groundwater rights available. Aquifer Storage & Recovery (ASR) fills the bill
ASR System Components Water Treatment Plant Kissel Wells Gardner Parker Gage The Right Geology High-yield aquifer Bounded/Bowl-shaped aquifer Compatible chemistry The Right Infrastructure Winter treated water supply Big yield wells Gravity distribution system
The Right Geology Aquifer is Ellensburg Formation sandstone Mineralogy is volcaniclastics (glass) Aerobic environment (redox reactions are not a concern) Surface water is a dilute from of groundwater. Naches River Groundwater ~1,000 feet Ellensburg Fm. Recharge Zone
The Right Infrastructure All major components are in place: 12 MGD winter water recharge supply Gravity transmission to 3,000 gpm wells Kissel Well ASR retrofitted for $30k Gardner Well installed with ASR capability Permit in place System scale clogging reduced Kissel Well efficiency 25% - 100% restored by back-flushing No clogging of Gardner Well (newer distribution system zone) Recharge pressure will be monitored to control clogging and conduct preventative flushing Kissel Well Recharge Production
ASR Program Development 19 years 1998: ASR potential recognized as climate change relief 2000: Kissel Well retrofitted for ASR & tested all s good 2002: Reservoir application submitted 2003: State ASR rule passed 2009: BoR/Ecology modeling defines recoverable quantity 2010: Purpose-built ASR well installed by City 2014: Gardner Well ASR Test 2015: Temporary permit issued 2015-02-24. 2016: Testing 2017: Permit issued by Ecology Water went into the ground starting 03-11-2015! Yakima Basin Integrated Plan
Key Permitting Point 1. Water Quantity Recoverable Quantity How Much Can I Recover? Based on water balance analysis: Water level data (empirical; e.g., tank level) Numerical Model (needs good calibration) Water levels in the Ahtanum Valley are very noisy (seasonal fluctuations, other groundwater users) Groundwater model: > 10% annual leakage
Key Permitting Point 2. Water Quality Chlorinated drinking water is recharged. Contains chlorination disinfection byproducts (DBPs; e.g., 10-40 ppb trichloromethane SDWA allows 80 ppb). Conflicts with WA Groundwater Antidegradation Rule (WAC 173-200 allows 7 ppb trichloromethane ). Variance allowed by Director of Ecology based on AKART analysis. Variance must be reviewed every 5 years. AKART Analysis of Different Treatment Technologies Existing GAC RO Cost ($M; 30-yr NPV @ 5%) $0.6 $2.9 $23 Implementability In place. Significant engineering/construction needed. Effectiveness THMs remain @ safe drinking water levels Removes DBPs; waste stream produced.
Key Permitting Sticking Point: Disinfection Byproducts DBP s below drinking water MCL but 6-7 times WA groundwater Rule Typical issue for Municipalities regulations slow program development Resolved with an Over Riding Public Interest and strict permit provisions: Requires a 5 year review and renewal DBP s limited to 50% drinking water MCL in recharge water Must cease recharge if exceeded
Permit Provisions (WAC 173-157 ASR Rule) Quantity: recharge up to 13 MGD & 14,400 afy Recovery: Not based on water quality Storage: Decreases 10% per year for 10 years Quality: 50% MCL for DBPs Monitoring: Monthly during recharge, less during storage Annual Reporting to Ecology Monitoring requirements reviewed in 2 years AKART Renewal: Every 5 years
Not Specified by Permit Standard Operating Procedure: When to recharge & monitor How much to recharge Who does what
The Yakima Plan Spend the first few years practicing Year 1 inject for 45 days in Gardner well Year 2 Inject in Kissel Well for 45 days Year 3, 4 and 5 Inject in both wells for 45 days Learn how to make an effective annual report to Ecology Possible reduction in testing and reporting About 2020: drill new dedicated ASR well About 2025: drill another ASR well and make all groundwater rights same well field We will have two fully redundant systems
Operational Scenarios Severe Drought (6 MGD Senior Rights) Without ASR: Water use restrictions - prorationing & all wells pumped at capacity Can t supply growth! With ASR: Wells supply 14 MGD balance or entire 20 MGD (could leave 6 MGD in stream!) Contamination or Water Plant Fail ASR supplies full demand up to 20 MGD in Summer or ~8 MGD in the winter
Benefits Beyond Municipal Supply Passive Recovery (Leakage to Surface Water): Water will be recharged every year, but only recovered when needed Leaked water could be used to mitigate rural development impacts Unrecovered water returns to the Yakima River above Parker Gage, and increases TWSA (e.g., 3 cfs modelled) Active Recovery: With 100% groundwater redundancy: City diversions could be temporarily suspended - making 40 cfs available Could pump directly to river
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Thank You! David Brown City of Yakima David.Brown@yakimawa.gov Supported by Washington Department of Ecology United States Bureau of Reclamation