Kokanee and chinook restoration projects
The Lake Sammamish Kokanee Work Group recently completed an effort to identify a short list of near term projects within the Lake Sammamish watershed that will contribute directly to the recovery of kokanee and Chinook salmon. The list of projects below, and the links to the conceptual design packages for these projects, is the result of this effort undertaken during 2010. The Work Group thanks the King Conservation District for providing the funding for this effort and thus making an important contribution to the health of salmon and their habitat, and to the quality of life for the residents of the Lake Sammamish watershed and the region.
These projects are scoped intentionally to be implementable by 2016 at the latest. The Work Group is now working with and encouraging jurisdictions and landowners with a role in implementing these projects to take key steps toward their implementation, including refining the project designs as needed, applying for grant funding, and placing the projects on the capital project lists for the respective home jurisdictions. The list purposely does not include multiple major projects, like fixing the culvert under I-90 that blocks upstream passage of salmon into upper Lewis Creek or the culverts on George Davis and Zaccuse Creeks that likewise block access to habitat spawning, as they are likely to be longer term projects.
- Lewis Creek: Delta Restoration
Restore natural shoreline by re-grading the beach to a shallower slope, and add a combination of wave buffers and plantings to retain finer sand material. Install bank and riparian habitat features near the mouth of the creek to help maintain a consistent channel grade across the beach.
- Lewis Creek: Gabion Reach Stabilization
Re-direct thalweg away from the gabion wall by excavating a narrower radius bend in the channel, creating a weir/pool formation in the channel to dissipate hydraulic energy, and installing large wood at the toe of the wall to prevent failure.
- Lewis Creek: Trash Rack odification
Re-design the trash rack to reduce the accumulation of debris and sediment that blocks the culvert intake and leads to impounded water. Develop best practices for future removal of debris to avoid sudden flushes of large volumes of water through the culvert and lower watershed.
- Ebright Creek: Wetland Enhancement
Install wood and other natural habitat features to consolidate diffuse flows through the Pereyra wetland and create a single, defined channel. Remove non-native vegetation and replace with native riparian species.
- Ebright Creek: Fish Passage Restoration
Remove a fish-blocking pipe culvert with a larger concrete box culvert to allow upstream migrating kokanee access high quality spawning habitat.
- Zaccuse Creek: Trail Culvert Removal
Remove the pipe culvert under the East Lake Sammamish Trail and replace with footbridge to extend daylighting of the creek and prepare for eventual ELS Parkway culvert replacement.
- Laughing Jacobs Creek: Sammamish State Park Channel Re-route
Create a new stream channel, including bed, bank, and riparian zone, through the Sammamish State Park wetland area south of the boat launch. Install a new fish-passable culvert under the ELS Parkway to connect with the upper reach of the creek through Hans Jensen State Park (Project H).
- Laughing Jacobs Creek: Hans Jensen State Park Habitat Enhancement
Enhance existing stream channel by installing pool-forming structures, bank softening measures, and additional spawning gravel. Re-route the reach downstream of the footbridge to tie in with new culvert under ELS Parkway (Project G) and create natural bed, bank and riparian areas.
- Issaquah Creek: Cybil-Madeleine Park Habitat Enhancement
Regrade banks to a gentler slope, add large wood and other pool-forming features, and create side-channel habitat with appropriately sized spawning gravel.
- East Fork Issaquah Creek: Confluence Restoration
Remove armoring and re-grade the right bank to a lower angled slope to increase connection to floodplain. Add large wood to the channel to create pool habitat and plant native riparian species on the banks to promote future wood recruitment. Excavate gravel from the confluence and redistribute upstream to encourage kokanee and Chinook spawning.
- East Fork Issaquah Creek: Third Ave & Creek Street Habitat Enhancement
Install a log weir to create a plunge pool that will dissipate the energy of high flows and help prevent scouring of spawning gravels downstream. Reconnect the flood plain where possible by removing bank armoring and re-grading slope to add flood storage capacity.
For questions about Lake Sammamish kokanee and related information, please contact Hans Berge, senior ecologist, Watershed and Ecological Assessment Unit.