West Virginia experiences a humid subtropical climate, with an average annual precipitation of around 44 inches. The major surface flows in the state are the Ohio River, Potomac River, and the Kanawha River. The state is home to several reservoirs and dams such as the Summersville Dam and Sutton Dam. The hydrology of West Virginia is influenced by its topography, with the Appalachian Mountains playing a major role. Major rivers and tributaries include the Elk River, Greenbrier River, and the New River. Snowpack in the higher elevations can contribute to spring runoff and water supply. The state faces challenges such as flooding and water quality issues due to mining and agricultural practices.