Longfellow Creek Natural Drainage System (NDS) Project

Photo of a street with natural drainage system
A natural drainage system before plants are installed.

Project Description 

Enhancing Our Communities with Natural Drainage Systems and Pedestrian Improvements 
Seattle Public Utilities (SPU) will construct natural drainage systems (NDS) at 3 sites in the Longfellow Creek basin. Natural Drainage Systems are built in the roadway shoulder (the space between the street edge and the property line) and are filled with deep-rooted plants and spongy soils that temporarily hold and clean polluted stormwater from streets and sidewalks before the stormwater enters our waterways.

Natural drainage systems offer multiple community benefits, including:

  • Increased landscaping
  • Lower risk of flooding
  • Creation of habitat along our streets
  • Healthier creek ecosystems
  • Traffic calming
  • More street trees
  • Pedestrian improvements

SPU is partnering with Seattle Department of Transportation on this project to provide pedestrian improvements at most sites, and this project is funded in part by the Levy to Move Seattle. 

Through our 1% for the Arts Program, we're adding an art installation at the 24th Ave SW and SW Kenyon St site. Based on community feedback, the art installation will also create a safe, community space to connect with neighbors and the surrounding habitat. Visit our online open house to learn more and provide your feedback on the current design.


The team is working to finalize the design for three of potential sites for the Longfellow Creek NDS project. We selected and designed the sites based on a variety of factors that included community input, recurring drainage and flooding issues, existing soil conditions, and availability of off-street parking.

Visit site map

What's Happening Now?

Visit our Online Open House! Learn more about the project, including design details for each site.

During 2021, we will:

  • Finalize the design for the natural drainage systems and pathway improvements
  • Continue to engage with residents, businesses, and community organizations around individual sites through design and construction

We expect construction on this multisite project to begin mid-2021 and go through 2022, we will provide notice about expected impacts prior to construction starting at each site.

Check out the Fact Sheet and FAQ to find out more about this upcoming construction project, and sign up to receive project email updates.

Community Benefits

This project will improve water quality in Longfellow Creek, as well as improve stormwater drainage, slow down traffic, provide pedestrian improvements, and beautify streets.
The project will also help the City of Seattle achieve its goal of managing 700 million gallons of stormwater runoff using green infrastructure by 2025.

Community Engagement

We are working to finalize the project design and prepare for construction. Please Please visit our Online Open House to learn more about the project and share your questions about construction.

If you're interested in learning more and finding out about upcoming community engagement events, please sign up to receive project email updates.

Art at 24th Ave SW & SW Kenyon St

Through the 1% for the Arts Program, Portland-based artist, Brian Borrello, is developing an art installation for the 24th Ave SW and SW Kenyon St site.

The artist’s goals are to make this place interesting for the community to visit and for the art to offer something unexpected, thought-provoking, and perhaps a little magical. This site is where life forces are nourished by the creek, where neighbors can connect with each other while they pass through, and where community can experience the natural world and its often-unseen processes.

Below is the artist’s proposed concept. Visit our online open house to learn more about the proposed art.

rendering of proposed art


2017 - 2018

  • Concept development for potential natural drainage systems sites
  • Initial outreach to basin residents about potential blocks

2019 – Mid-2020

  • Design development for selected sites
  • Design phase community engagement

Late 2020 to Early 2022

  • Share project update with community
  • Late design and Finalize project design and perform the construction contracting process
  • Pre-construction outreach including anticipated impacts as well as construction schedule and sequencing information

Mid 2021 to Early 2022

  • Construction on this multi-site project to occur
  • Provide ongoing construction updates to the community 


Natural drainage systems slow stormwater and filter out pollutants before they can harm our creeks and other waterways. Keeping pollutants out of our water is important for fish, aquatic life, and people.

Building a natural drainage system in Longfellow Creek basin is part of the Plan to Protect Seattle's Waterways. SPU used to call these "roadside rain gardens" but now calls them "natural drainage systems" or "NDS."

Why Longfellow Creek? Longfellow Creek is a salmon-bearing urban creek with degraded water quality adjacent to where people live, work, and play. Stormwater picks up pollutants from streets-including oil, heavy metals, and fertilizers-every time it rains and flows into the creek through ditches or pipes. This project will remove pollutants from the stormwater before it reaches the creek.

Funding Information

This project is paid for in part by the King County Flood Control District and the Levy to Move Seattle. Art at the 24th & Kenyon site is through the 1% for the Arts Program.