Monitoring juvenile Chinook salmon outmigration using rotary screw traps on the Sacramento River near Tisdale Weir

The Tisdale RST sampling site is operated by the California
Department of Fish and Wildlife (CDFW) to obtain information on the
temporal distribution, relative abundance, and composition of race
and species of juvenile Chinook salmon (Oncorhynchus tshawytscha)
and steelhead trout (O. mykiss) emigrating from the upper Sacramento
River and tributaries to the Sacramento-San Joaquin Delta (Delta).
The project collects data near the Tisdale Weir on the Sacramento
River, using two paired rotary screw traps (RSTs) outfitted with two
8-ft diameter cones.  The RST monitoring site at Tisdale Weir was established meet a
requirement of the 2011 amendment to the reasonable and prudent
alternative (RPA) of the 2009 biological and conference opinion (BO)
on the long-term operations of the Central Valley Project (CVP) and
State Water Project (SWP). The amendment required the Bureau of
Reclamation (USBR) and the California Department of Water Resources
(DWR) to fund a new juvenile salmonid monitoring site on the
Sacramento River between Red Bluff Diversion Dam (RBDD) and Knights
Landing. The purpose of the new site was to provide early warning of
fish movement and determine survival of listed fish species leaving
spawning habitat in the upper Sacramento River. CDFW issued ITP 2081-2019-066-00 to DWR on March 31, 2020, for the
long-term operation of the SWP in the Delta. Condition 7.5.2 of the
ITP requires the development and establishment of a spring-run
Chinook salmon juvenile production estimate (JPE) to increase
understanding regarding the impacts water operations have on the
spring-run Chinook salmon population in the Sacramento River
watershed and inform the development of minimization measures to
reduce take of spring-run Chinook salmon at Delta fish salvage
facilities. Data from the Tisdale RST will be used along with other
datasets from juvenile salmonid monitoring programs in the
Sacramento River Watershed to inform the development of JPE modeling
approaches. Salmonid data collected from the Tisdale RST, among other datasets,
is also used by the Salmon Monitoring Team (SaMT) to understand the
movement of juvenile salmon in the Sacramento River Watershed to
estimate the number of winter-run and spring-run Chinook salmon that
have entered the Delta. SaMT is a real-time operations monitoring
team required by Condition of Approval 8.1.2 of the ITP which meets
weekly from October through June, to provide advice for real-time
management of SWP operations to DWR, CDFW, and the Water Operation
Management Team (WOMT) to minimize take of winter-run and spring-run
Chinook salmon in the Delta.