The Patoka Watershed (HUC 05120209) covers about 1,282 square miles in southern Illinois and southwestern Indiana. The hydrology of the watershed is characterized by a mix of agriculture and forested land, with intermittent streams and small tributaries that feed into the Patoka River. The watershed receives an average of 45 inches of rainfall annually, with the majority of precipitation occurring during the spring and summer months. The watershed experiences a range of climatic and weather conditions, including occasional winter snowstorms that contribute to the snowpack in the higher elevations. The surface water quality in the Patoka River is affected by agricultural runoff and sedimentation, while the Patoka Lake reservoir, which was created by damming the river in the 1970s, offers significant recreational opportunities for the region. Recent trends show an increase in annual precipitation and more frequent extreme weather events, which may impact the hydrology and water quality of the watershed. Land use changes and conservation efforts are also being implemented to address the challenges facing the Patoka watershed.