Matthews Beach closes when it rains too hard. Raw sewage from combined sewer overflows dumps right where Thornton Creek enters Lake Washington. You live with the consequence.
Apply for Pilot ProgramYou already know the problem. The beach closes. After heavy rain, bacteria levels spike at Matthews Beach because the combined sewer system can't handle the volume. Stormwater overwhelms the pipes, and untreated sewage discharges into Lake Washington right where Thornton Creek enters.
That's a CSO - a combined sewer overflow. Seattle has been trying to fix them for decades with massive tunnel projects and pipe upgrades. But the root cause is simpler: too much water hitting the system too fast. Every roof, driveway, and lawn in the Thornton Creek watershed that sends runoff straight to the storm drain is contributing to the overflows that close your beach.
A bioswale doesn't fix the CSO infrastructure. But it reduces the volume of water that triggers the overflow. One bioswale captures hundreds of gallons per storm. Multiply that across the neighborhood and you're meaningfully reducing the load on a system that's been failing your beach for years. Matthews Beach residents don't need to be sold on the problem - you see it every winter.
Tailored stormwater and landscaping solutions for your property.
Custom bioswales for Matthews Beach's lakefront-adjacent lots. Designed to capture runoff before it reaches the creek mouth and Lake Washington.
Rain gardens, French drains, permeable surfaces, and CSO-reduction strategies. Keep your stormwater out of the combined sewer and off the beach.
Full-service landscaping using Pacific Northwest native species. Lakefront-appropriate designs that filter runoff and enhance your waterfront property.
We're selecting 5 founding homeowners for our first residential bioswale installations. If you live at the creek mouth and you're tired of beach closures, this is how you fight back.
Explore the Thornton Creek Watershed