The Spokane Valley-Rathdrum Prairie aquifer serves nearly 600,000 people in the Coeur‘d Alene and Spokane areas in Washington State. It is a federally-designated “sole-source aquifer,” meaning the region has no other sources of water and the aquifer needs special protection. Given the sole source aquifer designation, few alternatives are available for increasing water supply to the region.
A report called the Spokane Valley-Rathdrum Prairie Aquifer (SVRP) Optimized Recharge for Summer Flow Augmentation of the Columbia River is now available. The report was written for the Washington Department of Ecology (Ecology) by the state of Washington Water Research Center at Washington State University. The research was done as part of ongoing efforts to assure adequate water supplies in the SVRP aquifer and in the Spokane River in the face of population growth, ever-increasing groundwater pumping and expected effects of climate change.
According to the report, recharging the Spokane Valley-Rathdrum Prairie (SVRP) aquifer and the Spokane River with groundwater from near the southern portion of Lake Pend Oreille is technically feasible. However, having the study results doesn’t mean this project will ever be constructed. The study gives us the technical information we need to start a regional conversation about how to make up for the effects of groundwater withdrawals on the Spokane River during the critical, summer low-flow months. The study presents an alternative for communities in Idaho and Washington to consider in the future.
Large amounts of aquifer pumping have already decreased summer low flows in the Spokane River. Should conservation efforts fall short of meeting future demand, the pumping project appears to provide a technically viable option for enhancing summer flow conditions in the Spokane River and ensuring adequate water in the aquifer.
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