Leach, Braden2017-07-132017-07-132017-05Leach, Braden, "Analyzing Increases in Impervious Surface and the Effects on Hydrology and Water Quality in Big Sky, Montana" A paper to Satisfy Partial Requirements of an Independent Study (ENSC 492) Montana State University Department of land Resources & Environmental Sciences Spring Semester, 2017 p. 1- 26https://scholarworks.montana.edu/handle/1/13255An independent study under the supervision of Robert Payn in the spring semester of 2017.At a resolution of 30 m, there was a 26% increase in impervious surface in the West Fork of the Gallatin watershed from 1990 to 2005. After assessing the negative effects of impervious surface increase on aquatic systems, this review concludes that freshwater ecosystem health is likely to be the primary object of concern. Specifically, stream biota is negatively affected by reduced base flow and increased sediment loads that result when a watershed is overlaid by more impervious surfaces. Effective impervious surfaces, or impervious surfaces with gray stormwater infrastructure, have the greatest effect on hydrology and thus aquatic communities. Unless stormwater best management practices (BMPs) are implemented, greater increases in impervious surface will further stress freshwater ecosystems in the West Fork watershed and Upper Gallatin River.en-USWorking Paper