Just keep swimming… just keep swimming… is the imagined mantra for the anadromous salmonids that are currently making their way up waterways statewide. However, many of these hardy fish struggle to find adequate spawning ground when they reach their final destination due to a lack of coarse sediment build-up. This process typically occurs when dams block the resupply of sediment, exposing bedrock reaches that are unfavorable for spawning. An example of this problem exists on portions of the lower Yuba River below Englebright Dam, which borders the Sierra Foothill Research & Extension Center.
Chinook salmon in the Yuba River
Dr. Gregory Pasternick, UC Davis professor and researcher of watershed hydrology, geomorphology and ecohydraulics, is currently working on a “river rehabilitation” project at the Yuba River through SFREC. This has been an extensive effort involving the collaboration of researchers, the Army Corps. of Engineers, and the Fish and Wildlife Service to study and implement more suitable spawning conditions for the natural Chinook salmon and steelhead trout making their way up the river. Since 2007, nearly 15,500 short tons (361 cubic yards / 1 short ton) of gravel and cobble (sized 1-3 inches) have been injected into the reaches of the lower Yuba River below Englebright Dam. In the long-run, this project aims to inject a total of 60,000 - 80,000 short tons for maximum success. Prior to the efforts of the Pasternick Lab, zero salmon were spawning in the Yuba stretch above Deer Creek to the dam.
Gravel & cobble is injected into the river to create better spawning habitat.
The significant outcomes of this project will be seen years down the road when the river will serve thousands of Chinook salmon. “The population will at least have the spawning habitat to be able to grow over time, especially spring-run, which is the run that is most impacted right now in the Yuba,” shared Pasternick.
Englebright Dam keeps coarse sediment from the river.
Indicative advancements have already been made with the documentation of healthy spawning occurring over the past several years. In the coming months, the Yuba - along with rivers statewide - will be shining as resolute salmon and trout make their way “home”. While the inborn instincts push the anadromous fish up the rivers, efforts on behalf of researchers and managers help enable the successful regeneration of these vulnerable species.
The lower portion of the Yuba River has exposed bedrock which is the target site for improved spawning habitat.