King County Small Stream Basin Retrofit Siting Program
A stormwater capital needs assessment completed by Stormwater Services (SWS) in 2012 identified over 64 small streams/lakes in unincorporated King County considered to be degraded as a likely result of stormwater runoff from developed land because of (1) fair to poor biological health and/or a water quality impairment documented through County or State monitoring, and (2) the extent and age of development within the basin. This program will identify the stormwater retrofit sites necessary and feasible to match the flow durations of peak discharges as low as 8% of the forested 2-year peak discharge (ECY8%). This goal is referred to as "ECY8%" because of its focus on matching flow durations of peak discharges as low as 8% of the forested 2-year peak discharge. Use of this performance goal for stormwater retrofitting was derived from another planning effort completed by King County in 2012, called the Stormwater Retrofit Analysis and Recommendations for Juanita Creek Basin in the Lake Washington Watershed.