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Molasses Creek pipe

The Fairwood Crest Fish Barrier Removal project will modify an in-stream stormwater detention facility in Molasses Creek to allow fish to pass. Approximately 183-feet of pipe (consisting primarily of 48-inch-diameter pipe) and drainage structures (catch basins) will be removed. Approximately 190-feet of roughened stream channel will be created. This project will eliminate a seven-foot drop between pipes which creates a barrier for fish to return to native streams to spawn.

The new stream channel will be created generally along the existing stream corridor, but rather than being buried underground the stream will run through a new open channel. The topography and vegetation of the site immediately adjacent to the stream corridor will change from flat, grassy open space to a sloped open channel and with native trees and shrubs along the stream banks. The new channel will be lined with streambed material (sediment and cobbles), boulders and large woody debris. Other work at the site includes adjustments to the remaining pipe and catch basin system downstream of the new channel and planting a new riparian corridor along both sides of the new stream channel. The total project area just under an acre, and the total area of excavation and fill is about one-half acre.

King County has coordinated closely with the Fairwood Crest Homeowners Association, the primary landowner. The project requires a land use permit (a clearing and grading permit) to ensure the project is compatible with existing and projected land uses and plans.

The need for removal of the barrier is documented in HPA 2016-4-390+01.

Project location

The project is located within, and adjoining, the Fairwood Crest neighborhood community park and open space that lies in the 16500 block between 132nd Place Southeast and 133rd Place Southeast. This is within the Fairwood Park Division 11 neighborhood of unincorporated King County near the City of Renton.

Fairwood Crest fish barrier removal project location

Project timeline

Benchmark Targeted completion date
Community Outreach
Alternative Analysis
Preliminary Design
Final Design 2020
2nd Quarter 2021
3rd Quarter 2021
Operation & Maintenance Manual
1st Quarter 2022

Project documents

Lead agency

This project is being designed and managed by the King County Department of Natural Resources and Parks, Water and Land Resources Division, Capital Services Unit.  Our primary goal is to implement Surface Water Management Capital Improvement Program (CIP) projects by planning, designing, constructing and managing multidisciplinary teams and stakeholders.

Drainage problem?

For King County, report drainage problems online or call 206-477-4811.

For questions about the Fairwood Crest Fish Barrier Removal Project, please contact Rachel Berryessa, project manager, WLRD Capital Services Unit.