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.