DESCRIPTION
Lack of stable LWD has been proven to be a limiting factor for restoration of river processes for Dungeness salmon habitat. We propose to install engineered logjams at 3 sites on the Dungeness to provide habitat diversity/cover, roughness, stability, in order to reestablish river processes in these reaches, and in one case, to lessen the need for heavy irrigation equipment in-river. Engineered logjams have been installed by the Tribe in the past, and have proven themselves for the past 3 years during all flow levels. The need for logjams in these reaches is indicated in studies showing a lack of habitat (embedded LWD) and roughness to slow flows/sediment transport, and the stability required for the restoration of river processes.
Site 1: RM 2.8 is bordered by levees/armored banks, has a truncated meander and too much sediment, lacks embedded LWD and roughness.
Site 2: RM 6.6 is in conjunction with an irrigation "outtake" combined with a high quality creekside channel system that is dewatered when the river moves away from it. The project is bordered upstream by a major dike and downstream with the highest quality chinook side-channel documented. This project is in conjunction with a side-channel enhancement project.
Site 3: RM 8.5 lacks habitat, including embedded LWD, has poor bed stability, fast flows, nearby levees and bridges severely limit natural river processes.