Downtown Redmond Way Stormwater Treatment Facility

Vicinity Map

Location: Redmond Way and Sammamish River
Project Phase:
Construction Complete
Contact: Mike Haley, PE, Project Manager, 425-556-2723
Description:  As part of its regional treatment system, the City constructed a treatment facility for stormwater runoff from downtown Redmond. Construction included:
  • Installation of more than 900 feet of stormwater trunk line in Redmond Way that will out fall to the Sammamish River
  • Removal of existing oil / water separator in the West Gate Building parking lot and installation of a flow control vault, swirl concentrator, pump station, and media cartridge filter vault
  • Repair of asphalt pavement, curb, gutter and sidewalk in Redmond Way and the West Gate Building parking lot
  • Reconstruction of sanitary sewer from Redmond Way to the King County Metro line adjacent to the Sammamish River
  • Relocation of buried franchise utilities infrastructure in Redmond Way
  • Repair and restoration of the habitat features along the Sammamish River bank
Redmond Way Stormwater Treatment Facility

Storm water runoff from the streets and sidewalks enters the lower pump station vault and the flows are pumped to the upper filter vault which filters the storm water prior to discharge to the river. The first replacement of the 640 filters took place in February 2016. The filters trap about 90% of the suspended solid materials (dirt, garbage, rocks) that previously would have discharged into the Sammamish River. The photos below show before and after filter replacement.

Filters before and after replacement