Evaluate New Smaller Efficient Types of Low Head Fishways
* What smaller efficient fishway designs provide the best fish passage conditions meeting new lower hydraulic drop and velocity criteria?
Reclamation is actively involved in designing and providing guidance on fish passages in areas of anadromous fish runs throughout the Western United States. While the criteria have changed, the recommended design sizes have not changed--which would permit significant savings. There is a backlog of need for fish passage at hundreds of diversions on streams. Meanwhile, some projects are designing and building smaller size fishways without testing how effective they are. This project will test many smaller designs and evaluate their performance at varying flows. Multiple live fish species will be included in the evaluation for their specific efficiency and attraction to passage. Hopefully this will result in more definitive recommendations and wider acceptance of more efficient and cost effective fish passage designs for endangered species.
Need and Benefit
Reclamation has a real need for the above proposed research product in that the potential use and application of the results would be Reclamation-wide and not specific to any one given geographical area. Secondly, Reclamation in the Pacific Northwest Region is reviewing, approving, and proposing many of the fishway models proposed for this research project in many locations all over the Northwestern United States, and the findings would be put to immediate use.
Currently, to my knowledge, nobody else in the area is conducting similar research in these new smaller fishway designs and are looking to us for answers. Our Technical Service Center (TSC) Hydraulic Investigations and Laboratory Services group is one of the few facilities in the Northwestern United States which has the capability to conduct these tests. The results of these tests will likely be a big factor in getting regulatory agency acceptance such as National Oceanic and Atmospheric Administration (NOAA) Fisheries and state fish and wildlife agencies of the use and application of these more efficient designs. While natural type fishways are preferred where practical, where low flows are very low typical in small stream locations, these constructed fishways may be more efficient in providing sufficient depth of flow for fish passage than a natural type requiring more flow. End users ranging from the state fish and game departments, irrigation districts, and other soil conservation or river basin agencies would be the advocates for this research project.
Reclamation currently utilizes fish passage guidelines and fish passage designs which have been developed with the guidance of the regulatory agencies such as NOAA Fisheries and the state fish and wildlife services. These guidelines stipulate that, for anadromous fish, a maximum hydraulic drop of 1 feet is permissible while a maximum hydraulic drop of 0.5 to 0.7 feet is appropriate where passage of juvenile fish is required. Most of the standard fish passage designs for the vertical slot fishways and pool and chute or pool and weir designs and dimensions which have been tested have been based on the energy dissipation, velocities, and flow patterns which are generated by the one-foot drop criteria. For a one-foot hydraulic drop, a minimum fishway size of 8 feet wide by 10 feet long in that proportion produced the best hydraulic characteristics, while for pool and chute fishways a 10-foot-wide by 5-foot-long size worked to insure streaming flow was occurring. With the new criteria specifying lower hydraulic drops and velocities, there is a need to also evaluate what sizes for the various types of fishways work best as this would result in considerable savings and less impact.
The Hydraulic Investigations and Laboratory Services Group is one f the few facilities in the country that has the capability to conduct the testing necessary to have reliable accepance, such as the NOAA Fisheries and others will adopt and use the information gathered in this type of study. End users ranging from state fish and wildlife departments, irrigation districts, and other soil and water conservation or river basin agencies would be advocates for this project.
While other external sources have tested some of the above various types of fishways such as conventional vertical slot at lower hydraulic drops they have been focused on other fish species such as the shovelnose sturgeon etc and they have not to my knowledge used the smaller sizes of fishways being proposed. While testing labs have done circulation tests on small models of various vertical slot configurations, few have been tested on full operational size for testing with live fish on the models being proposed.
The need for testing these particular fishway models is because they are already being used in some form or another and up to a dozen are being constructed each year in some basins. As reviewers of these designs, we have an obligation to give o
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This information was last updated on February 28, 2015
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