The mission of the Palouse Water Conservation Network is to promote community awareness, education, and action to preserve and protect our underground water resources.
Our groundwater
Groundwater in the Palouse basin is pumped from two basalt aquifer systems. The basalt units are part of the Columbia River Basalt Group, which consist of thousands of feet of lava flows that cover most of eastern Washington as a result of massive "flood basalt" eruptions between 12 and 17 million years ago. The shallower Wanapum (Priest Rapids) aquifer is the primary water supply for rural residents of Latah County within the basin limits and in some areas of Whitman County.
Water levels in the Grande Ronde aquifer have been declining by 1 to 2 feet per year for 50 years or more. Wells in the Wanapum aquifer typically pump up to 1,250 gallons per minute (gpm) whereas wells in the Grande Ronde aquifer can pump in excess of 2,000 gpm. Water levels in wells in the Wanapum aquifer respond to changes in precipitation and pumping, suggesting the aquifer is recharged from the surface whereas steadily declining water levels indicate there is likely very little recharge to the Grande Ronde aquifer.
