The Lower Cheyenne Watershed covers an area of approximately 2,871 square miles in South Dakota and Wyoming. The hydrology of the region is dominated by the Cheyenne River, which flows through the area, and its tributaries. The snowpack in the region is significant, with an average of 30-40 inches of snowfall annually. Surface water is crucial for irrigation and drinking water, and there are several reservoirs within the watershed that help to store and manage water resources, including Angostura Reservoir and Pactola Reservoir. In recent years, the region has experienced more extreme weather events, including drought and flooding. This has led to concerns about the sustainability of water resources in the area. Additionally, the area has seen increased development and land use changes, which can impact water quality and quantity. Efforts are underway to monitor and protect the watershed, including through the use of best management practices for agriculture and land management.