Improving Data Collection Methods for Hydraulic Evaluations of Fish Screens
Can methods for collecting hydraulic data on vertical flat plate fish screens be improved to reduce evaluation cost
and increase measurement quality?
Hydraulic evaluations of fish screens are required by federal and state regulatory agencies to ensure that fish
screens comply with fisheries criteria. This research proposal addresses several questions related to current
methods for making velocity measurements on fish screens. The goal of this study is not to recommend changes
to criteria, but rather to improve methods by which Reclamation can evaluate fish screening facilities for
compliance with criteria.
Current National Marine Fisheries Service (NMFS) anadromous fish screen criteria (NMFS, 1997 and NMFS, 2011)
specify maximum approach velocities, minimum sweeping velocities, velocity uniformity requirements, and screen
evaluation requirements. Reclamation is required to conduct post-construction hydraulic evaluations to ensure
that screen hydraulics meet criteria. Flow control baffles are typically adjusted as a result of initial screen
evaluations, prompting subsequent evaluations. Evaluations also need to be completed if there are changes in
diversion operations or environmental conditions.
Evaluations of larger flat plate screens require significant effort in designing an instrument mount system,
collecting data, and analyzing results. If data are not collected properly (measurement too far from screen or
instrument interference) or if flow continuity through the screen is not met (data collected at the screen face does
not equal actual flow through the screens), field results may not be accepted by regulatory agencies.
Need and Benefit
Reclamation has the responsibility of delivering water to its customers in an economically and environmentally
sound matter. Conflicts between the needs of water users and the ecological needs of Endangered Species Act
listed species can lead to reductions in water diversions at Reclamation facilities. Reclamation continues to be
invested in projects where fish protection is required at water diversions. Results of this study will apply to new
and existing flat vertical plate fish screens with direct application to inclined screens, drum screens, and traveling
screens. Field evaluations of cylindrical screens are currently not accomplished because of difficulty in data
collection. Some results may be applied to cylindrical screens, but the unique challenges for evaluation of these
screens should be studied separately.
Reclamation is currently considering new flat plate fish screens for Roza Diversion Dam fish screening facility
(Yakima River near Yakima, Washington) and St. Mary Diversion Dam (St. Mary near Babb, Montana). New fish
screens may be needed in the future for the Bay Delta Conservation Plan and San Joaquin River Restoration Plan in
California. Floating surface collector systems are used to collect outmigrating juvenile salmonids for passage
downstream at high head dams in the Pacific Northwest. This type of design is being considered at Shasta Dam
with possible application for downstream fish passage at other high head Reclamation dams. The same velocity
limitations and measurement challenges relate to screens on floating surface collectors.
This study addresses questions about fish screen evaluations that have been discussed for many years, but not
researched due to limitations in individual project funds. Constructing a physical model in a hydraulics laboratory
provides a controlled environment for collecting accurate, repeatable data with consistent approach flow
conditions, good visibility for instrument positioning, and no debris accumulation or algal growth. These
environmental factors make field data collection efforts challenging. Improving the speed and accuracy of
hydraulic evaluations at fish screens will not only directly benefit Reclamation's fish screening facilities, but
application of these techniques by other federal and state agencies will benefit Reclamation's overall fish recovery
Contact the Principal Investigator for information about partners.
Bureau of Reclamation Review
The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.
Improving Data Collection Methods for Hydraulic Evaluations of Fish Screens (final, PDF, 2.1MB)
By Connie Svoboda, Tracy B. Vermeyen, Christopher C. Shupe,
Research Product completed on September 30, 2017