DESCRIPTION
This project seeks to build on the success of two previous projects (North Meander Slough Reconnection and North Meander Reconnection Phase II) by providing additional off-channel and main-stem refugia habitat for juvenile salmon in the lower Stillaguamish River. This scope of work focuses on identifying and advancing preliminary project design.
Snohomish Co. completed preliminary designs to reconnect approximately 0.5 miles of abandoned channel meander and restore about 8.5 acres of off-channel and mainstem refuge habitat in the lower Stillaguamish River at the North Meander. This project builds upon the success of two previous projects (01-1307 N Meander Slough Reconnection and 05-1605 N Meander Reconnection Phase II) and a proposed wood placement project (14-1289) which focus on the eastern portion of the remnant bend. Phase III investigated and planned restoration of the western portion of the N Meander enhancing connectivity with the Stillaguamish River and/or Cook Slough, in order to restore natural habitat forming processes for the purpose of creating off-channel rearing habitat for juvenile salmonids and foraging habitat for adult bull trout.
In addition to reconnection alternatives, different wood placement structures were evaluated to enhance habitat value, and hydraulic and sediment transport to the system as a whole. Four alternative scenarios were modeled, analyzed, and the preferred alternative selected. Preliminary design of the preferred alternative depict structures design and channel layout supported by stability calculations. Restoration design will include excavation of deposited material west of the current connection with the Stillaguamish River, channel reconfiguration, wood placement, and riparian planting. Deliverables will include a Preliminary Design Report aligned to the requirements in Manual 18 Appendix D-2.