Fishways - An Assessment of Their Development and Design: Final Project Report Part 3 of 4
culverts, design, engineering, Hydropower, instream flow, mathematical models, salmon, swimming speeds, trout, swimming, monitoring, Columbia River, denil, steeppass, Ice Harbor Dam, fish ladder, prototype, design criteria, fish response, fish passage, fishway design, economics, weir, pool, survey, attraction, attraction flow
Various areas of scientific and engineering endeavor in natural resources development and maintenance receive oscillating amounts of attention and support. As a result, and as reflected in the literature on fishways, the state-of-the-art receives pulses of useful information from research and the monitoring of completed projects. For example, such pulses of effort occurred in Britain and the United States in the late 1800s, in Belgium between 1908 and 1939, in Britain and the United States again from 1936 to 1940, and in the Pacific Northwest on the Columbia River in the period from the 1950s to the 1970s. Certain classical types of fishways have emerged from the documentation of this effort such as: The Denil chute fishway, the Alaska Steeppass, the Ice Harbor pool-port-weir fish ladder, and the Hell's Gate slotted fish ladder. Variations on each of these basic designs number in the tens, and they have been developed usually to meet specific site conditions, to handle smaller or fewer fish, or to test new design variables under prototype conditions. The design criteria developed from these experiences have emerged in a somewhat conservative aura. As a result, natural selectivity has been lost at sites where fishways have greatly reduced the size of the energy expenditure increments required for fish to negotiate a reach of stream. Designed fishways initially dealt with fish response to various flow configurations. But in the last 30-40 years more attention has been paid to stimulus, attractive releasers, and response in fish passage design. Numerous empirical studies have developed a rich reservoir of hydraulic and geometric information, and their associated design criteria. But, many fishway design topics have not received a fundamental analysis from the biomechanical and fluid mechanical perspectives. Also, many of the design criteria have not been thoroughly tested (not observed, but tested) in efficiency - in the efficiency of fish passage, water usage, and economics. For example, doubling the leaping height for a weir and pool fishway, for certain species would cut the cost of the structure by almost 50 percent. Water economies would result only at sites where there are competing uses for the flow, but that does not obviate the basic design objective of minimizing water use under any circumstances. Although numerous theoretical studies on the locomotion of fish and their hydrodynamic advantage have been reported, the instances wherein the results of these studies have been applied to the improvement of fishway designs have been scarce. Therefore, we have explored some of the components of fishway theory, design, and construction through: literature assessments, personal design surveys and interviews, theoretical and applied analyses (and testing) of stimuli, and the energy expenditure of ascending fish in various passage modes. A fundamental analysis of attraction flows, based on data from the USCE Bonneville Fisheries Engineering Laboratory, supplies the physical basis for fishway attraction flow design. Tests using typical fishway attraction flow and stream geometries with various species of fish are still needed to expand this analysis. Because much of the current fishway construction is being done in more remote and smaller systems, some consideration has been given to the use of alternative construction methods and materials. Also, because of the breadth and depth of the project and extensive bibliography is included in this volume. This report concludes with an appendix which summarizes the early stages of development of a new Weir, pool, and baffle fishway. Although testing has been conducted with only two species of salmon, the early results are very promising.