17th Ave NW Stormwater Improvements

Project description

Natural drainage systems use special soils and plants to capture rainwater, clean it, slow it down, and soak it into the ground.

Reducing street flooding and sewer problems in Crown Hill by building natural drainage systems

Some parts of the Crown Hill neighborhood experience street flooding or sewer backups. The 17th Ave NW Stormwater Improvements Project will address the area with the largest, most frequent flooding problems.

Flooding and sewer problems happen during rainstorms on 17th Ave NW because runoff from a large upstream area hits undersized, shallow pipes under the street. When the pipes fill, water bubbles up from inlets and ditches overflow into the intersection. Because the pipes are full, there’s nowhere for water to go until the system drains. A challenge for fixing the problem is that blocks downstream from the project area also experience flooding and sewer risks — if SPU were to simply increase the pipe sizes on 17th, it could worsen the downstream problems.

This project will use a mix of pipe improvements and aboveground natural drainage systems to improve drainage while protecting downstream blocks. This will take pressure off the system and help it handle larger storm events.

Location

The project will focus on the area between NW 90th Street and NW 85th Street. Most of the work will be along 17th Ave NW with some improvements on NW 87th St and NW 90th St.

Crown Hill Project site diagram. Click to enlarge.

What's happening now?

In summer 2023, members of the project team met with community members for a site tour and hosted a survey to gather input on SPU’s two proposed alternatives for addressing the stormwater and sewer problems in the project area. Thank you for your participation and thoughtful comments! Hearing from various perspectives – whether you commute through the neighborhood or are a resident on one of the project blocks – was incredibly valuable to us. As a result of your feedback, we’ll be developing a preferred alternative that is more reflective of the community’s priorities. To learn more about the latest round of engagement, read community sentiments on the plans, and find answers to frequently asked questions, please view our project planning engagement findings.

Currently, the project team is working with the Seattle Department of Transportation (SDOT) to incorporate community feedback into a final concept for the project. Once we have additional information, we’ll be reaching back out to the community and sharing the latest concept. Thank you for your interest in the 17th Ave NW Stormwater Improvements Project!

Community benefits

17th Ave NW is an important connection for students walking to and from Whitman Middle School. In wet weather, drainage problems make this route harder to use.

This project will significantly decrease the frequency of street flooding, a long-standing community concern. It will also decrease the risk of sewer backups to some homes on 17th Ave NW, and seek to address priorities from the City of Seattle’s recent community planning process, including the residents’ desire for pedestrian improvements and traffic calming on 17th Ave NW. Finally, increasing system capacity will help accommodate future growth. 

Community involvement

We're committed to providing timely information and updates on project activities. Updates may be available in multiple formats: this website, emails, drop-in sessions, briefings, and/or public meetings. There will be several opportunities for the public to engage and provide feedback during this process.