17th Ave NW Stormwater Improvements

Project description

Green stormwater infrastructure uses special soils and plants to capture rainwater, clean it, slow it down, and soak it into the ground.

Building green stormwater infrastructure in Crown Hill to reduce street flooding and sewer problems 

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

This project is part of the Crown Hill Stormwater and Sewer Plan (in development). This planning work will provide long-term direction for improving Crown Hill’s sewer and stormwater infrastructure; it identified 17th Ave NW between NW 85th Street and NW 90th Street as the highest impact problem area in Crown Hill. 

Flooding and sewer problems happen during rainstorms on 17th Ave NW because too much water hits undersized, shallow culverts under the street. When the pipes fill, water bubbles up from inlets and ditches overflow into the intersection. Because the system is full, there’s nowhere for water to go until the system drains. SPU’s project will use a mix of underground improvements and aboveground green stormwater infrastructure features to provide more room for stormwater. This will take pressure off the system and help it handle larger storm events.

Location

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

The Crown Hill Stormwater and Sewer Area Plan covers the entire Crown Hill Urban Village, which is centered around the intersections of NW 85th St and the 15th Ave/Holman Road NW corridors.

What's happening now?

We’re developing draft alternatives to address the stormwater and sewer problems. That includes studying site conditions and talking to SDOT about different possible ways to fit the necessary improvements into 17th Ave NW. 17th Ave NW is a neighborhood greenway that provides important pedestrian bike and pedestrian connections for Crown Hill.

This summer, we asked neighbors living and recreating in Crown Hill to share their thoughts through an online survey. The survey was available from June 15 through July 31, 2022, and we received 137 responses. These responses will help us establish alternatives for the project. A report summarizing what we heard is now available. Thank you for your input!

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 current and future growth.

What options are we looking at?

We are developing options that…

• Reduce the flooding at 17th Ave NW and NW 87th Street without increasing flooding risk to downstream blocks.
• Are consistent with SDOT standards for safe and complete streets.
• Provide pedestrian improvements and traffic calming.

We’re currently working to address those issues, and will share specific options here once they’re available.

Community involvement

SPU is 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.

We’re currently working to incorporate community feedback and new technical analysis into two alternatives for the project site. These alternatives will be available for public review and comment later in the fall. Check back for more information about upcoming opportunities to get engaged. Also, consider signing up for project updates.