Spokane County Stormwater Utility (SWU) is exploring a potential stormwater project along Cascade Way, between Wall Street and Division Street, in north Spokane. The project would retrofit the stormwater structures along Cascade Way to bring them closer to current water quality treatment standards. This retrofit project may include work that extends into the surrounding neighborhood streets around Cascade Way, depending upon the need and resources available.

Currently, polluted stormwater runoff is captured by drywells and then discharged – untreated – directly into the ground. These pollutants can include oils, heavy metals, and suspended solids, which originate from vehicles, equipment, and heavy machinery. Nitrates and phosphorus are also pollutants of concern and are found in runoff from fertilized lawns and landscaping. Current design standards are in agreement with the Environmental Protection Agency’s Clean Water Act, intended to protect our drinking water, as well as lakes, rivers, and streams, from stormwater pollutant contamination. 

The subsurface soils beneath this section of County road have been designated as susceptible for contamination with respect to connectivity to our sole-source of drinking water, the Spokane Valley-Rathdrum Prairie aquifer. Therefore, since there is currently no stormwater treatment in this area, this proposed project is desirable as a stormwater retrofit. The types of stormwater treatment improvement being considered for the Cascade Way area are as follows: roadside bioinfiltration swales, sand filters, and possibly porous pavement.