Holden Natural Drainage Systems Project

Example of a natural drainage system project a few years after installation

Project description

Improving creek water quality, increasing landscaping diversity, and providing roadway and pedestrian safety improvements

More than 12 million pounds of pollution are carried into our water bodies through stormwater runoff each year. Stormwater that falls on the roofs, streets, and parking lots in your neighborhood can pick up harmful pollutants before entering Longfellow Creek, which flows into Puget Sound. The pollutants can harm fish, wildlife, and our ecosystems. The Holden Natural Drainage Systems (NDS) Project is building natural drainage systems, also known as roadside rain gardens or bioretention, on SW Holden St between 16th Ave SW and 17th Ave SW to capture and treat stormwater runoff before it reaches Longfellow Creek and Puget Sound.

The NDS will be built between the existing sidewalks and the edge of the road. The project will include roadway and pedestrian safety improvements such as curb bulbs and ADA ramps, in addition to new landscape plantings.

Location

The Holden NDS Project area is along SW Holden St west of 16th Ave SW and half a block west of 17th Ave SW. The map shows the project area.

What's happening now?

The project team completed the final design in March 2025. We expect to award the construction contract in late 2025 and begin construction in 2026. SPU will provide advanced notice before construction starts.

To learn more about the Holden Natural Drainage Systems Project, please view the Final Design Narrated Presentation. 

Minimizing Construction Impacts

We understand that SW Holden St is a busy street for residents, businesses, and commuters. We will work to minimize construction impacts to the extent possible and will keep you informed before and during construction. Our project team will provide more details on construction timing and impacts before construction starts. The contractor is responsible for obtaining construction permits which include traffic control planning.

What to expect:

• Coordination: The SPU Project Manager will be available to address issues and broader community concerns.
• Work hours: Construction is expected to occur Monday through Friday from 7 am to 5 pm. Some work may also take place during evening or weekends if needed. More details will be shared once a contractor is hired and the construction permits are finalized.
• Road and sidewalk closures: Roads and sidewalks may be partially or fully closed during construction. Detour signs will be posted, and pedestrian detours that meet permit requirements will be provided. Pedestrian access and access to essential services (i.e. emergency vehicles, mail delivery, garbage pickup) will be maintained.
• Parking restrictions: Limited or restricted parking near the construction work zones.
• Noise, dust, and vibrations: Construction noise, dust, and vibration typical of a construction site.
• Access to homes and businesses: The contractor will work with property owners to maintain access to their homes and businesses during construction. Any temporary loss of access to driveways will be communicated in advance by the construction team. The contractor will also coordinate for garbage pick-up and mail delivery as needed.
• Bus stop relocation: The bus stop at SW Holden St and 16th Ave SW may be temporarily relocated. 

Community benefits

The Holden NDS Project will offer multiple benefits to local neighborhoods and ecosystems, including:

• Improved pedestrian safety
• Improved roadway elements
• Increased landscaping diversity
• Improved stormwater/drainage water quality
• Healthier creek ecosystems