The Fort Randall Reservoir Watershed (HUC 10140101) covers an area of approximately 4,425 square kilometers in South Dakota, USA. The watershed drains into the Missouri River, and its hydrology is influenced by snowmelt, rainfall, and groundwater. The region experiences a continental-type climate, with cold winters and hot summers. The average snowpack in the area is around 60 centimeters, with some areas receiving up to 90 centimeters. The watershed is home to the Fort Randall Dam and Reservoir, which provides water supply, irrigation, and hydroelectric power. The reservoir's primary constituents include sediment, nutrients, and dissolved minerals. Interesting trends in the area include a decline in snowpack and an increase in extreme weather events, such as flooding and drought. The Fort Randall Reservoir Watershed is an essential resource for both the environment and human populations, and its management requires careful monitoring and conservation efforts.