Allegheny River Lock & Dam 4

Website:
https://www.lrd.usace.army.mil/About/Districts/Pittsburgh-District/

Telephone Number:
(724) 224-2666

Location:
1 River Avenue, Natrona Heights, PA 15065

Description:

The Allegheny River Lock and Dam No. 4, situated in Harrison Township, Allegheny County, Pennsylvania, is a lock constructed between 1920 and 1927 and became operational in 1927, positioned 24.2 miles upstream from the river's mouth in Pittsburgh. This lock and dam infrastructure was meticulously built by the U.S. Army Corps of Engineers as part of an extensive system aimed at enhancing navigation along the Allegheny River.

Located approximately 24.2 miles upstream from the Point in Downtown Pittsburgh, it also lies approximately 6 miles downstream from the mouth of the Kiskiminetas River.

Upstream, Allegheny Pool No. 4 maintains an average water elevation of 745.4 feet above sea level, stretching about 6.2 miles to Allegheny River Lock and Dam No. 5. Downstream, Allegheny Pool No. 3 has an average water elevation of 734.5 feet above sea level, extending about 9.7 miles to Allegheny River Lock and Dam No. 3. Consequently, Lock No. 4 facilitates a vertical movement of approximately 10.9 feet for boats transitioning between these pools.

Featuring a single lock and a fixed-crest dam, the infrastructure ensures a minimum river depth of 9 feet in the pool above the dam. Although the local control of water flow over the dam is absent, it does not serve flood control purposes but contributes to providing water to municipalities.

In 1998, traffic through the lock amounted to about 1.8 million tons, including shipments of various commodities such as coal, petroleum, sand and gravel, ore, steel, chemicals, fertilizer, salt, flour, lime, and slag.

Recognized for its historical significance, the site was added to the National Register of Historic Places on April 21, 2000.