DESCRIPTION
The County is proposing to remove the lower 1,000 feet of the Hafner revetment and change the alignment of Neal Road while setting back the revetment to protect the road. The Hafner facility prevents lateral channel migration on the right bank and thus constrains the bankfull width of the river through this reach degrading salmon habitat. The setback of this constraint will allow lateral migration and result in widening of the channel. Setting the revetment and road back will greatly reduce the angle at which the river interacts with the revetment and thus the shear stresses during flooding on the road and agricultural lands behind it will be greatly reduced.
King County completed preliminary design of the Haffner-Barfuse project, renamed as the Fall City Floodplain Restoration Project, to restore natural riverine and floodplain habitat forming processes along a high priority reach of the Snoqualmie River. The project location, downstream of the Raging River and town of Fall City, is categorized as a mainstem primary restoration sub-basin in the Snohomish River Basin Salmon Recovery Plan. The preliminary design includes two high priority floodplain restoration projects that will remove or modify a levee and revetment on opposite sides of the Snoqulamie river. This two-in-one project combines two projects identified by the SRFB-funded Snoqualmie at Fall City Reach Assessment.
When constructed this project will increase and improve edge and off-channel habitat and gravel bar formation for juvenile salmonids and reduced scour of redds thereby benefiting adult salmonids. The Haffner and Barfuse projects will remove 2,600 feet of revetment or levee to allow unconstrained natural processes in approximately 145 acres of floodplain and reconnect almost a mile (0.85 miles) of side channel and increase forest cover and vegetative diversity on 110 acres in the floodplain and along waterways. In addition to salmon habitat improvements the project will benefit the local community with the construction of a newly aligned and modern Haffner revetment on the right bank and relocation of Neal Road SE to reduce regular flood damage to the road and property landward of the project area.
Once construction is complete (PRISM 20-1078), restored processes and habitat will contribute to the recovery of ESA-listed Chinook salmon and steelhead trout, as well as benefit other salmonids including coho, chum and pink salmon and cutthroat trout. As part of the preliminary design process King County engaged the community to raise awareness about the project and collect feedback and concerns. Engagement efforts included a virtual public meeting, public website, video tours, postcard mailing, and in-person meetings with nearby landowners and local Tribes. Preliminary Design meet standards in Salmon Grant Manual 18 Appendix D-2 and most of the Cultural Resources Review was completed for the project area and meets the RCO standards identified in Manual 18 Section 6.