The purpose of the Project is to improve instream and floodplain conditions for anadromous salmonids, specifically SONCC coho, as well as other aquatic species along a 0.37-kilometer-long reach of the Scott River dominated by Yuba Dredge tailings.
The goals of the Project are to:
1) Increase inchannel complexity and roughness within the Scott River Yuba Dredge Mine Tailings (Tailings) by the construction of instream Engineered Log Jams (ELJs);
2) Create instream pools associated with the ELJs to offer migrating adult and juvenile coho salmon and other aquatic organisms low velocity resting areas during migration, thereby improving fish passage success through the Tailings;
3) Create hydraulic diversity with instream ELJs to generate fine sediment storage and streambed substrate sorting to promote riparian vegetation success and improve spawning conditions for Chinook salmon;
4) Improve floodplain roughness with floodplain log structures to sort substrate and to capture fines to reduce instream fine sediment load and promote riparian vegetation success; and
5) Increase native riparian plant density by planting, increasing fine sediment deposition and soil water holding capacity, which will result in eventual improvements instream shade and primary food sources for fish.
To achieve these goals, the Project will install up to 20 instream ELJs, 40 floodplain log structures, and extensive native riparian vegetation, which will increase in-channel complexity, slow water refugial habitat for migrating adult and juvenile salmonids, capture and deposit fine sediment, and increase sorting of sediment.
This Project will be implemented in phases and authorized through the submission, review, and approval of annual workplans. Phase 1 is planned for implementation in the fall of 2022 and extends downstream 0.09 kilometers from the southern project boundary at Scott RKM 85.3. This phase will include extensive riparian planting and the installation of multiple ELJs. Phase 2 be implemented in 2023 and extends 0.12 kilometers downstream from Phase 1. This phase will include riparian planting and the installation of the additional ELJs. Future phases will construct more ELJs, conduct additional riparian vegetation planting, and undertake any required maintenance or adaptive management of previously installed structures and plantings.