In the 19th century, trees logged in the Tioga Valley were extensively used in shipbuilding. Logs were floated down the Tioga to the Chemung and on to the Susquehanna River, the Chesapeake Bay, and the shipyards of Baltimore.
Course
A panoramic view of the Tioga River Valley at Tioga, PA
The Tioga River has one major impoundment, the Tioga Reservoir, formed by a dam just before the borough of Tioga, Pennsylvania. The lake has a surface area of 498 acres (2.02 km2) and is administered by the United States Army Corps of Engineers, which built the Tioga Dam from 1973 to 1979. Built together with the adjoining Hammond Dam and Hammond Lake (on Crooked Creek), the total project cost $200 million.
The dam projects were initially authorized by the United States Congress in the Flood Control Act of 3 July 1958 (Public Law 85-500). Construction was begun in the aftermath of the devastating floods caused by Hurricane Agnes in June 1972, which resulted in widespread damage along the rivers. A channel connects the two lakes so that Hammond Lake (which has greater storage capacity) may be used to store excess (flood) water from Tioga Lake.
In addition to supporting flood control on the Chemung and Susquehanna rivers, the dams are also meant to help improve water quality by decreasing the acidity of water in the Tioga River downstream of the dams; it is diluted by addition of the more neutral waters of Crooked Creek. The Tioga River's acidity is caused by acid mine drainage.
