An Evaluation of Juvenile Salmonid Routing and Barrier Effectiveness, Predation, and Predatory Fishes at the Head of Old River, 2009–2012

The California Department of Water Resources (DWR) and the U.S. Bureau of Reclamation (Reclamation) manage the State Water Project (SWP) and Central Valley Project (CVP), respectively, and are charged to do so in a manner that maintains the survival of anadromous salmonids subject to the terms of the National Marine Fisheries Service’s (NMFS) 2009 Biological Opinion (BO) and 2011 amendments regarding the Long-Term Central Valley Project and State Water Project Operations Criteria and Plan (OCAP). Action IV.1.3 of the NMFS’s 2009 BO instructs these agencies to “consider engineering solutions to further reduce diversion of emigrating juvenile salmonids to the interior and southern Delta, and reduce exposure to CVP and SWP export facilities.” Specifically, one objective of Action IV.1.3 is to “prevent emigrating salmonids from entering channels in the south Delta (e.g., Old River, Turner Cut) that increase entrainment risk to Central Valley steelhead migrating from the San Joaquin River through the Delta.”