The Upper Sangamon Watershed (HUC 07130006) covers an area of approximately 1,216 square miles in central Illinois. The region is characterized by gently rolling terrain and a humid continental climate with hot summers and cold winters. The hydrology of the area is dominated by the Sangamon River, which is fed by numerous tributaries throughout the watershed. Surface water in the region is often impacted by agricultural and urban runoff, which can lead to high nutrient levels and pollution. The area receives an average of 23 inches of snowfall each year, and snowmelt contributes to spring runoff in the rivers and streams. The main reservoirs in the watershed include Lake Decatur and Lake Springfield, which are used for recreation and as a source of drinking water. Overall, the Upper Sangamon Watershed faces ongoing challenges related to water quality and quantity, including impacts from climate change such as increased frequency and intensity of extreme weather events.