The Illinois Watershed (HUC 17100311) is a large drainage basin encompassing approximately 10,000 square miles in central and northern Illinois. The hydrology of the watershed is dominated by the Illinois River, which serves as the primary surface water resource for the region. The area experiences a humid continental climate, with significant snowfall during the winter months. Snowpack in the watershed can contribute significantly to spring flooding events. The watershed is home to several large reservoirs, including Lake Springfield and Lake Decatur, which serve as important sources of drinking water and recreational opportunities for nearby communities. Recent trends in the watershed have included increased nutrient pollution from agricultural practices, leading to harmful algal blooms and decreased water quality. Additionally, climate change is expected to exacerbate flooding events in the region, with more frequent and severe rainstorms projected for the area.