Two adjustable waterfalls for evaluating fish jumping performance
low head dams, dams, fish population, migration, plunge pool, pool, pool and weir, fish passage, structures, barriers, adult, trout, raceway, flume
Journal or Book Title
Transactions of the American Fisheries Society
Instream obstacles such as low-head dams and waterfalls are important in fisheriesmanagement because they can restrict the movement of fishes. This can have detrimental orbeneficial effects on a fish population, depending on whether a particular structure operates as abarrier to migration or as a barrier to invasion. We developed flashboard-type and flume-typeadjustable waterfalls in the laboratory to study the effects of waterfall height and plunge pooldepth on fish jumping performance. Our ultimate goal was to provide a quantitative method ofevaluating pool-and-weir fish passage structures and waterfall barriers that could be applied tofield situations. The adjustable waterfalls were successfully tested using adult Rio Grandecutthroat trout (Oncorhynchus clarkii virginalis). The flashboard waterfall worked well inexperiments where the combined waterfall height and plunge pool depth were less than the depthof the raceway. The flume waterfall worked well for the same conditions, but as designed, itsminimum waterfall height was 30 cm. The flume-type waterfall also worked well for tests wherethe waterfall height exceeded the maximum depth of the raceway. Of the two waterfallsdeveloped, we recommend using the flume-type for future studies because of its greaterflexibility, even though it has a higher construction cost and is slightly more difficult to operate.