Mountain snowpack in the Bannock Range south of Kinport Peak provides the largest component of recharge (replenishment by the absorption or refilling of water) to the aquifer, particularly from accumulations in the Upper Mink Creek, Gibson Jack, and Scout Mountain areas. Snowfall in these mountains, up to 30 inches per year, melts and seeps into the ground, flowing by gravity through pore spaces in the rock and soil. It eventually ends up in the aquifer beneath the valley floor.
Precipitation falling in the valley floor (10-12 inches per year) does not provide a significant amount of recharge to the aquifer. Most of the precipitation runs off of lawns and city streets, flowing through the storm drain system and into the Portneuf River.
The diagram below shows the distribution and estimated inches of precipitation that fall in the watershed.