The U.S. Army Corps of Engineers Pittsburgh District is notifying the public that onsite work to build stone fish reefs on the Monongahela River near the borough of Elizabeth will begin Oct. 30.
The work is the first of five segments of a $2.4 million contract to install the fish reefs between Monongahela River miles 21.3 and 33.5. The work will begin at river mile 33.5 in Pool 3, between Victory Hills and the city of Monongahela, and continue downstream to river mile 21.3 in Pool 2 near Clairton, Pennsylvania.
A ‘floating plant,’ which is a barge purposed for on-river construction, will be used to import and install the R-5 riprap stones at the river pools. The stone fish reefs’ purpose is to mitigate habitat loss that will result from removing Elizabeth Locks and Dam.
Construction work will not affect private property located along the river. The river-navigation channel and commercial navigation will not be affected by the construction.
The fish reefs construction is a part of the Lower Monongahela River project, which includes the construction of the larger lock chamber at Charleroi Locks and Dam, and the removal of Lock and Dam 3 at Elizabeth, Pennsylvania. Corps of Engineers contractors have completed Pool 3 channel dredging and installed the gated dam at Braddock Locks and Dam.
In the summer of 2024, the Elizabeth Locks and Dam removal is expected to disrupt fish habitats due a change in water levels and hydraulic flow in the river pool.
Designed by the Pittsburgh District, the reefs will help offset potential harm to aquatic life. The structures will provide protected areas for fish and other wildlife.
The reef locations (see map) may vary depending on the river site conditions. Each reef will extend 50 feet into the river, perpendicular to the shoreline.
“Building these fish reefs will help us mitigate ecosystem impacts from removing Elizabeth Locks and Dam, as well as create connectivity between pools 2 and 3,” said Steve Frost, the project manager for the Lower Monongahela River project.
After contractors remove the dam at Elizabeth, Pennsylvania, and pool level equalization, 52 fish reefs will have a 3-foot draft (water depth over the reef) or more, and 21 reefs will have between 1- and 3-foot draft.
The U.S. Environmental Protection Agency, U.S. Coast Guard, U.S. Fish & Wildlife Service, PA Fish & Boat Commission and PA Department of Environmental Protection have coordinated with the Corps of Engineers regarding the fish reef construction.
source: U.S. Army Corps of Engineers Pittsburgh District