Army Corps of Engineers to start fish reef construction on the Mon
Construction of a series of fish reefs on the Monongahela River near Elizabeth is set to begin today.
The U.S. Army Corps of Engineers Pittsburgh District will begin reef construction at Pool 3 between Victory Hills and the city of Monongahela. The work marks the beginning of a five segment, $2.4 million project that aims to offset habitat loss after the Elizabeth Lock and Dam is removed in mid-2024.
“I’m very excited, as project manager, to get this going with the fish reefs. It’s innovative. They’re pretty much stone and gravel structures that replicate habitat for the fish species in the Monongahela River,” said Steve Frost, Corps project manager of the Lower Monongahela project.
Construction will not impact the river navigation channel, commercial navigation or private property along the Mon.
The reefs are part of the Lower Monongahela project, which launched in 1994. The LMP includes recent projects like dredging at Pool 3, a new gated dam at Braddock Locks and Dam and construction of the Charleroi Locks and Dam’s larger lock chamber, which is set to begin operation next year.
Next summer, Lock and Dam 3 at Elizabeth will be demolished, Frost said, and the 73 fish reefs are expected to be completed before dam 3 is removed.
“We’re hoping to mitigate the loss of the tailwater when we remove Lock and Dam 3, specifically dam 3,” Frost said, noting the dam removal will open up the river. “We’re going to create connectivity between tributaries which were separated by the dam and the two different pools. Connectivity between the tributaries is really important for the fish and the fish habitat as well.”
A “floating plant,” or barge built for on-river construction, will import and install stones at river pools, eventually creating fish reefs that extend from river mile 21.3 to mile 33.5.
Construction of the manmade reefs begins at Mon River mile 33.5 and will continue downstream toward Clairton.
Reef locations will vary depending on site conditions, but all reefs will be situated perpendicular to the shore and extend about 50 feet into the water. The Corps of Engineers said 52 reefs will rest three or more feet under the Mon River’s surface, while 21 reefs will be covered by between one and three feet of water.
While reefs constructed of natural elements, like trees, have been built to mitigate habitat loss elsewhere, this is the first time the Corps of Engineers is creating fish reefs solely from constructive materials in the Pittsburgh District, which is comprised of 26,000 square miles of waterways in Ohio, New York, West Virginia, Maryland and Pennsylvania.
“They’re not coral reefs. They’re pretty much stone and gravel structures that replicate habitat for the fish species in the Monongahela River,” Frost said. “This is the first time we’ve done fisheries like this and we’ve coordinated with agencies within the state, and also the federal government, to try to understand how to do this.”
The state Department of Environmental Protection, PA Fish & Boat Commission, U.S. Fish & Wildlife Service, the U.S. Environmental Protection Agency and the Coast Guard will assist the Corps in the reef construction.