South Lake Washington Shoreline Restoration Project
DNR manages approximately three acres of filled shorelands in South Lake Washington. The property is located adjacent to the Boeing plant and is adjacent to the mouth of the Cedar River - a critical migratory corridor for Chinook salmon.
The property was created in 1965 when 150,000 cubic yards of fill was placed into the lake. The fill was placed alongside a flume made of two sheet-pile walls that was used to release cooling waters from the Shuffleton Steam Plant.
The derelict flume is approximately 650 linear feet and made up of two sheet pile walls that are approximately 20 feet apart. The site is also overgrown with Himalayan blackberry and other invasive plants and the shoreline is littered with concrete and other debris. Three dolphins made up of 21 creosote-treated piles are located on the eastern side of the property.
The objective of this project is to restore approximately 1,300 linear feet of shoreline habitat and approximately three acres of upland habitat to improve and restore the water quality of the lake and nearshore migratory habitat for juvenile Chinook salmon.
This is a Tier 1 priority under the WRIA 8 Chinook Salmon Conservation Plan due to the project’s location in a migratory and rearing corridor. Restoration will accomplish priority actions under the conservation plan by increasing overhanging vegetation and reducing bank hardening by restoring important shallow water habitats closest to the mouth of the Cedar river - where such habitat is most heavily used by juvenile Chinook salmon (Tabor 2006).
South Lake Washington site before restoration.
Phase 1, currently underway, includes a feasibility study, conceptual design, final design of the project, and initial monitoring studies. The 30% design for the project is complete. The following actions are proposed in the design in order to meet the restoration objectives:
- Remove approximately 550 linear feet of outer flume sheet pile wall and associated cross beams
- Remove approximately 371 linear feet of inner flume sheet pile wall
- Place 9,000 cubic yards of fine gravel, sand, round cobble, and sediment along the shoreline to create shallow water habitat
- Remove non-native invasive plants from the 3 acre upland property and re-plant native vegetation
- Plant native vegetation that will hang over the shoreline
- Restore a 0.29 acre wetland
- Remove three derelict dolphins from the lake consisting of approximately 21 creosote-treated piles
- Remove rip rap and other debris from the shoreline
- Place three Engineered Log Jams (ELJ) along the shoreline
- Extend two stormwater outfalls into deeper waters
Funding for Phase 1
| 2009 -2011 Aquatics Restoration Funding||$ 47,000 |
| Washington Department of Ecology||$ 13,500|
| Salmon Recovery Funding Board (SRFB) grant||$154,000 |
DNR is currently working with US Fish and Wildlife Service to complete salmon monitoring along the project shoreline. The monitoring is occurring before construction and once the shoreline is restored. The data will allow us to report pre and post-project fish counts at the project site and two control sites.
Phase 2 - Coming July 2012
Project Construction is being funded by the Washington State Department of Transportation, The Boeing Company, and DNR.
Final Lake Washington/Cedar/Sammamish Watershed (WRIA 8) Chinook Salmon Conservation Plan. 2005.
Tabor, A. Roger, Howard A. Gearns, Charles M. McCoy III, and Sergio Camacho. 2006. Nearshore Habitat Use by Juvenile Chinook Salmon in Lentic Systems of the Lake Washington Basin. U.S Fish and Wildlife Service Annual Report, 2003 and 2004.