Head OF Old riVer Barrier installatiOn and FlOWs - San Joaquin ...

data collected by both programs. In addition, an array
of hydrophones and receivers capable of tracking fish in
two dimensions was installed at the Old River Barrier at
Tracy to examine the behavior of tagged fishes as they
interacted with the barrier.
The pilot study was designed to (1) test various
assumptions inherent in the experimental design for
quantifying survival of juvenile salmonids in the South
Delta, and (2) provide preliminary information on the
behavior of these fishes near the temporary barriers.
Results of the studies will be used to assess the potential
significance of the temporary barriers to salmon and
steelhead migrating through the South Delta. Results of
these investigations will also provide useful information
on predator-prey interactions that could serve to reduce
the potential vulnerability of juvenile Chinook salmon,
steelhead, and other fish species to predation mortality
near the temporary barriers.
Results of the 2009 pilot study in combination with
information from similar survival investigations, such as
those performed as part of the VAMP, will be used as part
of the technical foundation for the 2010 and 2011 fullscale
studies. The specific objectives of the experimental
investigations are to provide qualitative and quantitative
information about the movement, behavior, and survival
of juvenile salmon, steelhead, and green sturgeon within
the South Delta. Results of the fishery investigation are
intended, in part, to provide information on the design
and operation of the future permanent operable gates.
36 / 2009 Annual Technical Report
The permanent operable gates are a major component of
the South Delta Improvements Program (SDIP) which
is currently in the planning, design, and environmental
documentation development processes.
The study design will be looking a several important
management questions including:
• Does relative abundance of predatory fish change in
response to the installation of the temporary barriers?
• Do predatory fish exhibit site fidelity or learned
behavior near the temporary barriers?
• What is the response of predatory fish behavior to
changes in the near field hydraulics associated with
the temporary barriers?
• Does the distribution and behavior of predatory fish
vary in response to operation of the temporary barriers
(i.e. flap gates open or flap gates closed)?
• What is the behavior of sensitive fish species (salmon,
steelhead, and green sturgeon) as they pass the
temporary barriers?
• What is the survival of out migrating juvenile salmon
and juvenile steelhead within the South Delta during
the time when the temporary barriers are installed?
A full study design is available from the technical team
at the California Department of Water Resources.