Evaluating the Impact of a Waterfall on Upstream and Downstream Habitat Conditions and Fish Diversity

Abstract

Rivers are unique ecosystems that are constantly under risk of being overused and degraded to a point where native species are put at risk. In order to best protect species, it is important to understand the microhabitats that they depend on. This study examines the impact of waterfalls on dissolved oxygen, water temperature, turbidity, and stream velocity, and the impact of these habitat characteristics on fish diversity at various locations upstream and downstream from the falls on the Big Sioux River in Sioux Falls, South Dakota. Habitat conditions were found to be significantly different (p<0.05) when comparing upstream and downstream conditions for all of the characteristics except water temperature. Dissolved oxygen and velocity were found to be higher downstream than upstream, while water clarity was found to be lower downstream (indicating a higher turbidity). Fish diversity was found to be higher upstream from the waterfall, however, not at a statistically significant level. Velocity was found to have the greatest impact on determining the diversity of fish at a particular location.