How does infiltration affect Redmonds groundwater?
Precipitation and stormwater infiltration sustain the aquifer that Redmond uses to supply 40% of its drinking water. Percolation in natural, undisturbed areas provides clean water to the groundwater aquifer. Stormwater collected from man-made areas such as clean roof run-off can also beneficially recharge the aquifer. Stormwater from roads, parking lots, and industrial areas however, may pick up oils, metals, and other contaminants not beneficial to the aquifer. The shallow groundwater aquifer in the valley areas of Redmond may be only a few feet below the surface and is highly susceptible to contamination, so infiltration of contaminated stormwater is a potential problem. Who regulates stormwater infiltration? Owners or operators of any facility within the City of Redmond’s Wellhead Protection Zones 1 and 2 are required to evaluate and upgrade their stormwater infiltration systems to ensure protection of the drinking water resource. The City of Redmond’s 2003 Wellhead Protection Ordin
