Red Bluff Fish & Wildlife Office
Pacific Southwest Region

Red Bluff Diversion Dam - Juvenile Salmonid Monitoring

Multiple runs of Chinook salmon in a single sample

Multiple runs of Chinook salmon in a single sample
Photo Credit: USFWS

Rotary trapping during RBDD gates raised operations (Fall 2004)

Rotary trapping during RBDD gates raised operations (Fall 2004)
Photo Credit: USFWS

Trap configuration during 2002 BOR "Crown Flow" experiment

Trap configuration during 2002 BOR "Crown Flow" experiment (Summer 2002)
Photo Credit: USFWS

View of rotary traps atop RBDD during gates out period

View of rotary traps atop RBDD during gates out period (Winter 2003)
Photo Credit: USFWS

Juvenile Green Sturgeon

Juvenile Green Sturgeon
Photo Credit: USFWS

Rotary traps sampling with RBDD gates down (Summer 2004)

Rotary traps sampling with RBDD gates down (Summer 2004)
Photo Credit: USFWS

The Red Bluff Fish and Wildlife Office (RBFWO) established a juvenile fish monitoring program using rotary-screw traps at the Red Bluff Diversion Dam (RBDD) in 1994. The initial objectives of the juvenile monitoring program were to assist in the evaluation of the Red Bluff Research Pumping Plant (RBRPP). The plant was constructed by the Bureau of Reclamation to explore alternative methods for delivering agricultural water to the Tehama-Colusa Canal, rather than the diversion system currently in place. Juvenile passage estimates for all four "runs" of Chinook salmon, steelhead trout and relative abundance information for a host of other native and exotic species were generated and provided to the RBRPP to determine possible impacts on emigrating fishes from operation of the plant. Rotary-screw traps were used to evaluate the RBRPP from July 1994 through June 2000.

Sampling was not conducted from July 2000 through March 2002, while funds were being secured through the California Bay-Delta Authority (formerly CALFED). Sampling at RBDD resumed in April of 2002 and has been continuous to the present day. The Dam, located at river kilometer 391 on the Sacramento River about four kilometers southeast of the city of Red Bluff, CA, has proven to be an ideal site for juvenile Chinook monitoring. Moreover, the site is superlative for the monitoring of state and federally listed Endangered winter Chinook salmon for two reasons. First, the winter Chinook spawning grounds lie almost exclusively above RBDD (Vogel and Marine 1991) and up to four, eight-foot diameter traps can be attached to the dam and sampled simultaneously within a transect across the river. The physical structure and operations of RBDD control the channel morphology and the hydrological characteristics of the area providing for consistent sampling conditions for evaluating trends in juvenile abundance within and between years, and for developing a time invariant trap efficiency model. The model and quantitative methodologies were developed to estimate numbers of outmigrants passing RBDD while decreasing the program’s reliance on and need for experimental fish, thereby minimizing impacts on Threatened and Endangered species. These methodologies have been independently reviewed by biological statisticians.

The primary objectives of this project at present are to (1) obtain juvenile winter Chinook production indices and to correlate these indices with estimated escapement from adult estimates provided by the winter Chinook carcass survey, (2) define seasonal and temporal patterns of abundance of winter, spring, fall and late-fall run Chinook salmon and steelhead trout passing RBDD and (3) obtain relative abundance information (catch per unit volume) for green sturgeon and lamprey to monitor trends in abundance. Additionally, the juvenile monitoring program currently provides bi-weekly real-time summarized daily passage estimates (of all four runs of Chinook and steelhead trout) to the Calfed Operations Data Assessment Team (DAT) and Operations and Control Office (OCO) Calfed Operations group via email. Passage data is provided to agency personnel, stakeholders and water managers at the Central Valley Project's Tracy Pumping Plant and the State Water Project's Harvey Banks Delta Pumping Plant diversions on a real-time basis such that winter Chinook juvenile entrainment at these facilities may be limited. To be added to the list of recipients who are provided biweekly reports, please email redbluff@fws.gov with your request. The biweekly reports are being archived by the USFWS and are available on this website (see link below).

Final reports of information derived from Juvenile Salmonid Monitoring at RBDD

Real-Time Biweekly Reports of Juvenile Salmonid Passage at Red Bluff Diversion Dam

Last updated: March 24, 2014