Angostura Reservoir
Watershed Hydrology
The Angostura Reservoir Watershed (HUC 10120106) covers an area of approximately 1,500 square miles in South Dakota. The watershed is characterized by rolling hills, grasslands, and croplands. The hydrology of the area is influenced by the Cheyenne River, which is the main source of water for the reservoir. The watershed receives an average of 20 inches of precipitation annually, with the majority falling as snow in the winter months. The snowpack in the area is important for the reservoir's water supply. The reservoir is used for irrigation, municipal water supply, and recreation. The primary constituents of the reservoir include sediment, nitrogen, and phosphorus. Interesting climatic facts and trends include an increase in average annual temperature and a decrease in snowpack over the past few decades. These trends may have implications for water availability and quality in the future.