Modifications of a Turbulent Fountain for Use as a Fish Screen in Small High-Gradient Streams

Abstract

We tested the efficacy of a modified turbulent fountain for its ability to screen fish from an irrigation diversion in McCabe Creek, Montana. We released westslope cutthroat trout (Onchorynchus clarlci lewisi) into the intake of a prototype fountain in order to field-test screening capability and impingement rates. We then corrected observed flaws in the screen and repeated the test to compare efficacy of the prototype to the modified, more "fish-friendly" design. Fish lengths were similar between the two tests. Following modification of the prototype screen, the number of impinged fish declined from 37 to 6 percent. The duration of impingement declined by 93 percent, from a median of 30 to 2 sec. This evaluation indicated that turbulent fountain screens, when designed and constructed with proper fisheries considerations, can be effective at screening fish and providing a low-maintenance, more practical alternative to traditional fish irrigation screening devices on small streams.