Wellsville is the junction of many foothill streams including Dyke Creek feeding the Genesee River from the east. The water from Hurricane Agnes in 1972 exceeded the capacity and banks of Dyke Creek, producing a rapid and huge pool of water at the center of the village. The extent of the damaged area continued downstream through Scio and Amity until the valley widened to accept the large flow of water in the lesser populated area. Erosion of topsoil during this flood eliminated many small farms.