Changes coming to 17th Ave NW in Crown Hill to address frequent street flooding and stormwater overflows

The City is looking at making some drainage improvements to 17th Ave NW and NW 87th St, where the streets often flood during heavy rain, causing sewage overflows into residents’ basements.

Seattle Public Utilities, in collaboration with SDOT, has developed two possible options for improving drainage in the area. They’re looking for community feedback via an online survey to inform their design plans.

SPU says sometimes stormwater can overload the sewer pipes in the area, which can cause sewage overflow into basements south of NW 85th St. The area is susceptible to flooding and sewer problems because many blocks in north Crown Hill drain to 17th Ave NW, where the existing drainage pipes are too small and flat to handle anything more than a small rainstorm, SPU says.

The two options for improvements combine pipe upgrades and natural drainage systems, which are shallow depressions along the edge of roadways.

“They use special soil and deep-rooted plants to slow stormwater and filter out pollutants – like rain gardens, but on a larger scale. Together, these improvements will help reduce street flooding by an estimated 95% in large storms,” SPU says.

Here are the options SPU is currently considering:

SPU will use the feedback to inform which street design features to consider in the project’s final design. They ask that respondents fill out the survey by July 26.