The Conococheague-Opequon watershed (HUC 02070004) covers approximately 1,790 square miles in Virginia, West Virginia, Pennsylvania, and Maryland. The watershed is characterized by a mix of forested areas, agricultural land, and urban areas. The hydrology of the watershed is influenced by the Blue Ridge Mountains and the Appalachian Mountains, which affect the amount and timing of precipitation. The snowpack in the watershed can vary from year to year, but generally peaks in February or March. Surface water in the watershed includes the Opequon Creek, Conococheague Creek, and their tributaries. These streams provide habitat for a variety of fish species. Reservoirs in the watershed are used for water supply, recreation, and flood control. Interesting climatic facts include the fact that the area experiences hot and humid summers and cold winters, with average temperatures ranging from 20°F in January to 85°F in July. Climate change is expected to increase the frequency and severity of extreme weather events in the watershed.