Spokane Valley Rathdrum Prairie Flows in WRIA 55

The Spokane Valley Rathdrum Prairie Aquifer moves out of WRIA 57 through two main subsurface channels, the Hillyard Trough and the Trinity Trough. Flow through the Hillyard Trough is north towards the Little Spokane River where aquifer water discharges to the Little Spokane River as baseflow and springs or seeps. Several well-known springs exist in this area including Waikiki and Griffith Springs. The Spokane Hatchery is supported by flows from Griffith Springs. Several studies have computed estimates of flow through the Hillyard Trough to the Little Spokane River, these estimates range from 182 to 335 cfs.