1 River Avenue
Natrona, PA. 15065-2609
Lock and Dam 4 is located at Natrona, PA
Lock and Dam 4 was built from 1920-27, and opened in 1927.
Lock and Dam 4, like all navigation facilities on the Allegheny River, consists of a single lock chamber and a fixed crest dam. This type of dam is basically a concrete weir or wall across the river which keeps the river channel upriver of the project deep enough for navigation -- about 9 feet or more. Water which flows over this type of dam cannot be controlled locally. Consequently, it cannot provide any control over flood waters. An incidental benefit derived from the pool formed by the dam is the availability of a source of municipal and industrial water.