Rathdrum Comprehensive Aquifer Management Area based on the boundary of the Spokane Valley-Rathdrum Prairie Aquifer clipped at the Idaho border. Boundary describes the extent of the Spokane Valley-Rathdrum Prairie aquifer from south end of lake Pend Oreille, Idaho - thru Rathdrum Prairie, the Spokane valley, turning north to discharge at little Spokane river, and Spokane river north and west of the city of Spokane. Spokane Valley aquifer (WA State only) was originally digitized in 1988 by Spokane Co. Engineer Dept from USGS 1977 hydrologic study of the Spokane Aquifer. This layer digitized from 1:24000 quad maps into the County's GDMS GIS. It was modified in June 1994 by Spokane County WQMP-GIS and again in March 1995 based on data from additional aquifer studies conducted by CH2Mhill. The Idaho portion of the Aquifer data came from Idaho Panhandle Public Health GIS in March 1993. The Aquifer boundary was redrawn based on new data from a coordinated ground and surface water monitoring program conducted in 2004-2005. The study reassessed the hydrogeology and water budget of the Spokane Valley-Rathdrum Prairie Aquifer (Aquifer). Data was originally digitized at a 1:24000 scale.

Rathdrum Comprehensive Aquifer Management Area based on the boundary of the Spokane Valley-Rathdrum Prairie Aquifer clipped at the Idaho border. Boundary describes the extent of the Spokane Valley-Rathdrum Prairie aquifer from south end of lake Pend Oreille, Idaho - thru Rathdrum Prairie, the Spokane valley, turning north to discharge at little Spokane river, and Spokane river north and west of the city of Spokane. Spokane Valley aquifer (WA State only) was originally digitized in 1988 by Spokane Co. Engineer Dept from USGS 1977 hydrologic study of the Spokane Aquifer. This layer digitized from 1:24000 quad maps into the County's GDMS GIS. It was modified in June 1994 by Spokane County WQMP-GIS and again in March 1995 based on data from additional aquifer studies conducted by CH2Mhill. The Idaho portion of the Aquifer data came from Idaho Panhandle Public Health GIS in March 1993. The Aquifer boundary was redrawn based on new data from a coordinated ground and surface water monitoring program conducted in 2004-2005. The study reassessed the hydrogeology and water budget of the Spokane Valley-Rathdrum Prairie Aquifer (Aquifer). Data was originally digitized at a 1:24000 scale.