Controlled Explosives Breach Elizabeth Dam On Lower Mon
A contractor for the Pittsburgh Engineer District blasted away the first portion of the Monongahela Dam 3 near Elizabeth, Pa., about 7 p.m. on July 10.
The explosive demolition, which was delayed for a few hours because of high wind and rough water, is the first of 14 scheduled to occur on a weekly basis to breach the dam and create a 30-mile pool on the Monongahela River between the dams at Charleroi and Braddock on the lower Mon. The Joseph B. Fay Company of Pittsburgh was awarded the contract for the demolition.
Controlled explosives removed a 50-foot section of the fixed-crest dam. The Corps planned to close the waterway to traffic for at least three days following the first blast to allow for the upper and lower pools to level out on the river.
Once the river has leveled, all navigation must lock through the landside chamber until the entire dam is removed and the contractors have cleared the construction area. That effort is scheduled to take about six months, into December, according to the Pittsburgh Engineer District. Once the contractors have removed the dam and cleared the riverway, all waterway users will be able to navigate through the area without using the lock chambers.
The district will begin removing the lock walls in 2025, with the work expected to continue through 2027. The concrete debris from the locks and dam removal will be repurposed to stabilize the facility’s land wall and dam abutment, which will remain in place.
Removing the dam is part of the Lower Monongahela River Project. Once complete, the project is expected to bring an economic benefit of $200 million annually, including cost-time savings in transporting commodities through the region using inland navigation and reduced maintenance costs, the Pittsburgh District said.
Other parts of the project have included the construction of a larger riverside lock chamber at Locks and Dam 4 at river Mile 41.5 near Charleroi, Pa., and the replacement of the fixed-crest dam with a gated dam at Locks and Dam 2 in Braddock, Pa.
Monongahela River Locks and Dam 3 have been operating since 1907, but the facility is prone to flooding and must therefore be shut down during high-water events, resulting in navigation delays, the district said.
Removing the dam raises the river’s water levels by approximately 2 feet for communities between Elizabeth and Braddock. The river elevation drops by approximately 3.2 feet between Elizabeth and the dam in Charleroi. The demolition will result in the pool level reaching 723.7 feet between Charleroi and Braddock.
The drop in the water between Elizabeth and Charleroi also means Charleroi’s landside lock chamber will be unusable for navigation. While its future refurbishment still remains authorized by the Corps, the plan signed by the assistant secretary of the Army in 2014 defers work on the landside chamber until the 2050s.
