Lower American River Salmonid Gravel Augmentation and Side-Channel Habitat Establishment Program
This ongoing salmonid gravel augmentation and side-channel habitat establishment effort is made possible by continued collaboration with the Water Forum, US Bureau of Reclamation, and the US Fish & Wildlife Service.
The program was created to address habitat reduction and fisheries decline in the Lower American River, and annually fosters the design and installation of at least one habitat enhancement project. Project objectives are increasing the quantity and quality of spawning and juvenile rearing habitat for Fall run Chinook salmon (Oncorhynchus tshawytscha) and Central Valley Steelhead (O. mykiss). cbec has provided planning, design, and construction monitoring for the program since 2010. To date nine separate projects have been completed at 7 different sites, with one additional currently in the design stage.
Past projects have included the placement of designed gravel features (i.e., spawning riffles, islands and bars), in-stream habitat features (i.e., boulder clusters and large wood installations), side channel creation, and in-channel material placement to increase the inundation frequency of existing side channels. To optimize habitat enhancement opportunities, multiple complementary elements are often used in combination for any given project. To support both design and post-project assessment, cbec provides physical monitoring services (e.g., topographic and bathymetric surveys, installation and maintenance of continuous water surface elevation instrumentation, and velocity measurements via acoustic Doppler current profiler), two-dimensional numerical hydraulic modeling and habitat suitability modeling, and preparation of construction plan sets. cbec also participates in a multi-stakeholder technical advisory panel to develop the structure of the ongoing monitoring and adaptive management process.
Post-project monitoring has documented the incredible success of this effort with high spawning and rearing activity occurring in the sites after construction. At many sites little to no spawning or rearing activity was observed for several years prior to implementation. The Nimbus Basin site constructed in 2014 had over 600 redds documented in the first spawning season. The annual utilization varies, but up to 40% of the total redds documented in a single year have been located in these project sites. The most recently constructed of these projects is the Upper Sailor Bar site, which was completed in the fall of 2019.
The videos below showcase select sites of the Lower American River Salmonid Gravel Augmentation and Side-Channel Habitat Establishment Program.