The Spokane valley- Rathdrum Prairie Aquifer is a natural resource that supplies 500,000 people drinking water. Discovered in 1895, the aquifer has become one of most important resources in our area. In the 1970’s area residents saw the need to protect that resource. Because it spans 2 states the EPA (Environmental Protection Agency) was was elected to oversee our aquifers safety. It has been said that there is no city in the world that has a better water supply.
As seen on the attached map, the EPA aquifer boundary and the sole-source aquifer boundary are not always the same. Within the sole-source aquifer boundary, water on the surface of the land infiltrates, or seeps downward to the groundwater below, recharging the aquifer. The sole-source aquifer boundary excludes areas where recharge comes from sources other than the land surface. One such area is near the southern shore of Lake Pend Oreille, where most of the recharge to the RPA(Rathdrum Prairie Aquifer) is from the lake and not from infiltration from the land surface.
DEQ (Department of Environmental Quality) has classified the RPA as a sensitive resource aquifer (IDAPA 58.01.11.300.01.a), following EPA’s aquifer boundary as seen in the map link below. Because of this classification, all activities that could impact the water quality of the RPA must be carried out so they maintain or improve existing quality of the ground water (IDAPA 58.01.11.301.01.a).
The Panhandle Health District also recognizes the EPA aquifer boundary and has adopted rules to allow only one septic tank and drainfield for every 5 acres over the aquifer to avoid impacting water quality. A map of the EPA aquifer boundary used by both DEQ and the Panhandle Health District can be found on the RPA Reports/Publications web page.
In January 2007, Kootenai County established the RPA Protection District. The aquifer protection district boundaries correspond to the areas over the RPA and adjacent upland areas that contribute water to the RPA. The upland areas are also known as Critical Aquifer Recharge Areas. Creation of the aquifer protection district allows Kootenai County to charge an annual fee to residences and businesses with the boundary. The money is used to fund aquifer protection programs and activities.
We sell and service advanced treatment systems that can treat wastewater on smaller than 5 acre lots. They are available as an option instead of traditional septic systems for your home. Hopefully this Rathdrum Prairie Atlas will help you understand more of the magic beneath you. This is a resource that many people have spent countless hours creating. Enjoy
Click here for a link to The Spokane valley - Rathdrum Prairie Aquifer Atlas