In this portion of the special session, I will be giving an introductory overview of the current state of understanding of the Spokane Valley Rathdrum Prairie Aquifer from a geologic, hydrogeologic, and geographic standpoint as well the regulatory, statutory, and grassroots organizational overview.
The SVRPA is the sole source of drinking water for the city of Spokane, the greater Spokane Valley, and Kootenai County Idaho’s combined 600,000+ residents with few exceptions. the SVRPA is an EPA designated sole source aquifer. Kahle and others (USGS 2005) noted that "The hydraulic conductivity of the aquifer's sediments is at the upper end of values measured in the natural environment."
The SVRPA is uniquely singled out in Idaho statute as a Sensitive Resource Aquifer (SRA) due to both its susceptibility to contamination and Kootenai County’s reliance on the resource for potable water with no alternative practical source of drinking water available.
Given the socioeconomic gravity and importance of maintaining the water quality of the SVRPA for the benefit of the residents of Kootenai County, the Idaho Groundwater Quality Rule states in 58.01.11.301.01 that:
“Activities with the potential to degrade Sensitive Resource aquifers shall be managed in a manner which maintains or improves existing ground water quality through the use of best management practices and best available methods.”
Additionally in the state of Washington, RCW 36.36.040 established a renewal of the Spokane Valley Rathdrum Prairie Aquifer Protection Area (APA) with support from a majority of voters in August of 2025.
The renewal of the APA allows for monies to support preparation of a comprehensive plan to protect, preserve, and rehabilitate subterranean water, including groundwater management programs adopted under chapter 90.44 RCW, amongst other specific aquifer protective activities.
This special session aims to highlight the state of the science and bi-state protection of this region's primary drinking water source.