Clifton Court Forebay is operated as a regulating reservoir within the Sacramento-San Joaquin Delta to improve operations of the State Water Project’s Banks Pumping Plant at the head of the California Aqueduct. Clifton Court Forebay is tidally filled and water is diverted from Old River into the forebay through the operation of five radial gates. When the radial gates are opened, fish are entrained in Clifton Court Forebay and must make a minimum 2.1 mile crossing of the forebay before reaching the John E. Skinner Fish Protection Facility. Losses of fish during movement from the radial gates to the fish protection facility, termed pre-screen loss, include predation by fish and birds. The NOAA Fisheries OCAP biological opinion (2004) required investigations to (1) quantify predation losses on juvenile steelhead within Clifton Court Forebay, and (2) identify potential management actions to reduce predation mortality of juvenile steelhead. The steelhead pre-screen loss investigation is a pre-condition to increasing State Water Project export rates to 8,500 cfs.
The steelhead pre-screen loss investigation is a collaborative effort with participation from the DWR Fishery Improvements Unit, DFG Fish Facilities Unit, USBR Fisheries and Wildlife Resources Group, and Hanson Environmental, Inc. Multiple tagging and monitoring technologies are being used to address various research objectives.
Spring 2005: Year 1 Pilot study
Winter 2006: Year two pilot study
Fall 2006: Field setup for full-scale study
Winter/Spring 2007: Field work for the full-scale study
Summer-Late Fall 2007
: Data analysis
Winter/Spring 2009: Final report
The final report for the Steelhead Pre-screen Loss Study is now available:
Quanitification of pre-screen loss of juvenile steelhead in Clifton Court Forebay (PDF 9.4 MB)
Kevin Clark, Principal Investigator
California Department of Water Resources
1416, 9th Street, Room 252-35
Sacramento, CA 95814