The Sulphur Headwaters watershed (HUC 11140301) is a large watershed located in southwestern Montana and southeastern Idaho. The land area of the watershed is approximately 1,630 square miles, and it is primarily mountainous terrain with elevations ranging from 5,000 to over 11,000 feet. The hydrology of the watershed is dominated by the Yellowstone River, which is fed by numerous small streams and tributaries. The watershed experiences a significant amount of snowfall each winter, with some areas receiving over 200 inches annually. This snowpack is an important source of surface water for the watershed during the spring and summer months. The reservoirs in the watershed are primarily used for hydroelectric power generation and irrigation, and they contain a mix of sediment and dissolved minerals. In recent years, the watershed has experienced warming temperatures and decreased snowpack, leading to concerns about the long-term sustainability of the region's water resources.