Search

Lower Monongahela River Project

Pittsburgh District
Published Jan. 10, 2024
Dam chamber on Monongahela river filling with water.

The U.S. Army Corps of Engineers Pittsburgh District begins to refill the newly constructed lock chamber with water at the Monongahela River Locks and Dam 4 in Charleroi, Pennsylvania, May 25, 2023. The chamber will take several days to fill with approximately 18.5 million gallons of water. Once filled, the Pittsburgh District will move forward with installing the miter gates and testing out the lock for navigation. The new lock is expected to go into operation in 2024. The construction project at Charleroi is part of the Lower Mon Project, sometimes referred to as a "mega project" because of its size and scope. (U.S. Army Corps of Engineers Pittsburgh District photo by Michel Sauret)

Dam chamber on Monongahela river filling with water.

The construction project at Locks and Dam 4 at Monongahela River mile 41.5 is nearly complete and ready to refill with water before installing the miter gates in Charleroi, Pennsylvania, May 23, 2023. The chamber is part of the Lower Mon Project, sometimes referred to as a "mega project" because of its size and scope. Nearly 90 percent of the work on the project is now complete, at a $1.2 billion cost. It began with the installation of a new gated dam at Braddock (Monongahela River Locks and Dam 2), replacing the former fixed-crest dam, before work shifted to Charleroi. (U.S. Army Corps of Engineers Pittsburgh District photo by Michel Sauret)

Dam chamber on Monongahela river filling with water.

The construction project at Locks and Dam 4 at Monongahela River mile 41.5 is nearly complete and ready to refill with water before installing the miter gates in Charleroi, Pennsylvania, May 23, 2023. The chamber is part of the Lower Mon Project, sometimes referred to as a "mega project" because of its size and scope. Nearly 90 percent of the work on the project is now complete, at a $1.2 billion cost. It began with the installation of a new gated dam at Braddock (Monongahela River Locks and Dam 2), replacing the former fixed-crest dam, before work shifted to Charleroi. (U.S. Army Corps of Engineers Pittsburgh District photo by Michel Sauret)

Construction project at Monongahela River Locks and Dam 4

Stephen Dine, the U.S. Army Corps of Engineers Pittsburgh District resident engineer for the Charleroi construction project, offers a tour of the Monongahela River Locks and Dam 4 to Max Robinette, a reporter for the Mon Valley Independent, in Charleroi, Pennsylvania, May 31, 2023. The Pittsburgh District has refilled the newly constructed lock chamber with 18 million gallons of water and has entered the final construction phase. Next, the district will install miter gates and test the mechanical and electric locking components. The district expects the new lock to go into operation in 2024. The construction project at Charleroi is part of the Lower Mon Project, sometimes referred to as a "mega project" because of its size and scope. (U.S. Army Corps of Engineers Pittsburgh District Photos by Michel Sauret)

Locks and Dams 2, 3 and 4 on the Monongahela River in Allegheny, Washington and Westmoreland counties in southwestern Pennsylvania are the three oldest currently operating-navigation facilities on the Monongahela River. These locks experience the highest volume of commercial traffic on the entire Monongahela River Navigation System and the pools created by these facilities provide industrial and municipal water, and are popular with recreational boaters.

The Lower Mon project replaced the nearly 100 year-old fixed-crest dam at Braddock Locks and Dam with a gated dam, will remove Locks and Dam 3 in Elizabeth and construct two new larger locks (Charleroi Locks) at Locks and Dam 4 in Charleroi.

Current Active Construction:

  • Pool 3 Dredging (completed in March, FY2022)
  • Stilling Basin (anticipated to be complete in FY2022)
  • Charleroi River Chamber and Control Tower (anticipated to be complete in FY2024)