What happens to stormwater in King County?
Stormwater flows downhill through various constructed collection and conveyance structures, such as ditches and pipes, and through natural pathways such as streams and rivers. No matter which route it takes, stormwater eventually reaches Puget Sound. In addition to ditches and pipes, other stormwater structures include stormwater ponds, vaults, swales, and culverts. Together, the structures belonging to one municipality such as a city or county make up what is known as that municipality’s municipal separate storm sewer system. The storm sewer system is usually separate from the wastewater system, but the storm and wastewater systems are combined in some older areas, such as much of downtown Seattle.
No matter the route it takes, stormwater eventually reaches Puget Sound. Stormwater flows downhill through natural pathways, such as streams and rivers, and manmade structures like sidewalks, driveways, roads, ditches and pipes. Historically, municipalities have engineered elaborate systems of pipes, ditches, and other structures to remove stormwater from developed property to prevent flooding. These systems typically involve little to no treatment of the stormwater as they are designed to transport it efficiently to a waterbody like a stream, river or directly to Puget Sound.
