Mattole Watershed Mid-River Large Wood Augmentation Planning Project

The project: (1) used field visits and hydraulic modeling to characterize 27 miles of Mattole River and high priority tributary streams; 2) developed a Large Wood Augmentation Plan for the reaches; 3) Completed 100% design for at least 150 non-engineered large wood structures over a minimum cumulative reach length of seven miles (in low risk and smaller channels w/ BFW<35), and 100% design for 15 engineered wood structures in larger/higher risk channels to treat at least 3000 feet of higher risk stream channel.

Implementation of the instream features designed in this project will improve spawning conditions by forcing the development of pool-riffle morphology in plane bed channels and causing deposition of gravel in reaches currently dominated by larger material, reducing local shear stress and decrease the chance of redd scour; and will improve rearing conditions by greatly increasing the availability of velocity refuge from high flows, improving access to floodplains, and increasing instream cover.