The Pymatuning Reservoir is a reservoir in the U.S. states of Ohio and Pennsylvania. It has a capacity of 64.275 billion gallons at 69.15 km ² water surface. The lake is 27 km long with an average width of 2.57 km, a maximum depth of 10.7 m and a level of 305 meters.
The lake is completely in two eponymous state parks, their common boundary is identical to the state line. The parking area with the waters of a total of 126 km ² of which 30 km ² land and 55.5 km ² water surface on the Pymatuning State Park (Pennsylvania ) and 26.8 km ² of land and 13.65 km ² water surface on the Pymatuning State Park ( Ohio).
The first inhabitants of the area were Moundbuilders the Monongahelas who left the area for unknown reasons. Two of their mounds are below the current dam. The white settlers had problem with the marshland or lost their livestock in quicksand. Hazardous swamps, floating islands and the uncertainty about being able to tell where the land ended and the sea began were commonplace. Bears, mountain lions, and foxes had as predators rich booty. Mosquitoes that could transmit yellow fever, difficult life in addition. A boardwalk should remedy the situation and make the area passable. Some farmers began individual sections of the swamp to drain acreage for onions to create.
1868 was determined by explorations that the entire area drained, could be drained and dried out to convert it into agricultural land. The hopes of the farmers were, however zunichtegemacht because it was also found that a dried marsh would destroy the industrial needs of the Beaver Valley and Shenango Valley.
In 1911 it was decided to commission a feasibility study for a dam construction in order. 1913 caused a flood deaths and damage in excess of 3 million U.S. dollars. After that, $ 1.2 million was provided by the Legislature for a dam construction. However, Governor John Tener reduced the amount to $ 100,000. It took until 1931 until all necessary lands were acquired and Governor Gifford Pinchot made $ 1.5 million for the dam construction are available. With the help of 7,000 people, the dam was completed in 1934. The total cost of the project amounted to $ 3,717,739.
The three main reasons for the construction were stockpiling of drinking water for industry and households along the Shenango and Beaver Valley, a retention basin to prevent future flood disasters and the development of a recreation area.
From 1937 to 1971, the Water and Power Resources Board was responsible and then the Department of Environmental Resources, which set up also the Pymatunig State Park. At the lake there are bald eagles and numerous waterfowl. The lake has, among others, Sander vitreus and muskellunge.