Pipers Creek Natural Drainage System (NDS) Project

Rendering of street view of project

Pipers Creek project rendering

Project description

Improving creek water quality, reducing flooding, and providing multiple community benefits.

Polluted runoff is the greatest water quality threat to Puget Sound and the Salish Sea. For more than 100 years, pollution from urban activities have harmed the water quality of Puget Sound. The main source of this problem is stormwater runoff. Runoff drains over 370 billion gallons of polluted water from urban areas into the Sound each year. (PDF)

Stormwater that falls on the roofs, streets, and parking lots in your neighborhood can pick up harmful pollutants and carry them into Pipers Creek, which flows into Puget Sound. The pollutants can harm fish, wildlife, and our ecosystems.

The Pipers Creek Natural Drainage System Project will design and build several blocks of natural drainage systems (NDS) cells in the Bitter Lake neighborhood to treat about 4-5 acres of polluting surfaces. The NDS cells will help capture and treat stormwater at the source before it drains into Pipers Creek and Puget Sound. 

This project is part of SPU's Plan to Protect Seattle's Waterways, which aims to improve water quality and reduce pollution from stormwater flows into Pipers Creek and Puget Sound, and help manage stormwater by constructing natural drainage systems in your neighborhood.


The Pipers Creek Natural Drainage System Project is in the Bitter Lake neighborhood along Dayton Ave N and Phinney Ave N, between N 115th St and just south of N 130th St. The area being considered for NDS is limited to the Pipers Creek watershed due to regulatory funding requirements, which is why the northern project boundary is between N 127th St and N 130th St. View the Pipers Creek project map.

NDS systems will not be built on every block in the project area, nor along the front of every home on a block. As design continues, the project team will narrow down the selection of blocks where NDS systems will be installed. Other drainage and non-drainage improvements (paving, drainage collection structures, landscaping) within the City right-of-way may also be built within the project area.

What's happening now?

The design phase for this project was restarted in 2024 after pausing in 2023 to bring on a new, specialized consultant design team and conduct soil testing to inform the design. The project is currently in the early design stage. As work resumes, the project team will be evaluating locations to construct NDS and other improvements in the project area. You may expect to occasionally see SPU team members in the neighborhood as they work on this technical evaluation. The design phase is expected to continue through 2026, with construction beginning as early as 2027.

Community benefits

Natural drainage systems offer multiple benefits to local neighborhoods and ecosystems, including:

  • Increased landscaping, including street trees and plants
  • Lower risk of water pooling along the side of the road
  • Creation of habitat along our streets
  • Healthier creek ecosystems
  • Traffic calming
  • Path and/or sidewalk improvements in the vicinity of the new NDS facilities

We are working with the Seattle Department of Transportation (SDOT) so that pedestrian improvements associated with the Home Zone program can be implemented in coordination with this project. The locations of pedestrian improvements have not been finalized. For more information on SDOT improvements, please contact Chris Kartheiser at Chris.Kartheiser@seattle.gov.

Community input

Community input will be essential to this project alongside technical evaluations in each project phase. The project team will work with neighbors and community members throughout the design process to understand important issues in the neighborhood and identify appropriate locations for natural drainage systems.

We have worked closely with the community in previous options analysis efforts and will continue to do so as we advance in the design process. We expect to gather community input again in fall or winter of 2024, once our design team has developed preliminary design options for the 10% design milestone. In the meantime, we will work with individual homeowners as we identify feasible sites for NDS cells throughout the project area. Sign up to receive email updates when public input opportunities become available.

Early 2024

  • Develop options analysis (10% design)

Late 2024

  • Public meeting(s) for community information and feedback

Early 2025

  • Complete options analysis (10% design)

Late 2025

  • Continue design and community engagement


  • Complete design


  • Start construction


  • Complete construction

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.