U.S. Army Corps of Engineers Green River Lock and Dam No. 6 near Brownsville, Kentucky, has been removed. The removal was performed by experienced dam removal personnel under an interagency support agreement between the Corps’ Louisville District and the U.S. Fish and Wildlife Service. Other participating agencies were Kentucky Department of Fish and Wildlife Resources, Mammoth Cave National Park, The Nature Conservancy and Kentucky Waterways Alliance.
A decision was made to remove the lock and dam because it was failing in place and posed safety risks. An uncontrolled breach occurred in November of 2016. There was a failure in several sections of the dam to include structural damage, such as cracking and tilting of the lock walls.
The Louisville District’s biggest concern and reason for pursuing the removal was to remedy the public safety risk for those who use the area for recreation using kayaks and canoes. “Demolition and removal of Green River Dam No. 6 has multiple benefits. First it removes a very dangerous safety hazard that was created with the entire flow of the river passing under the dam and lock,” said Mike Turner, Lousville District biologist. “Anyone drawn into this would have had no hope of escape or survival.”
“For removal, we knocked down the lock walls, placed the debris in the lock chamber, and graded and seeded two slopes, so it looks just like the river bank. Floods or even just high water will transport tree seeds to the exposed soils where they will sprout and cover the slope within one to three years,” Turner said. The lock and dam were removed using hydraulic hammers with some of the excavated rock being placed in the lock chamber. The removal took approximately 16 days. An experienced dam removal team with Fish and Wildlife service who specialize in this unique demolition had done similar work in Texas, North Carolina and up the east coast.
The dam’s removal means that the river will be open for recreational traffic with better access, especially kayaks and canoes, with nearly all trips ending at the ramp in Brownsville. This will increase tourism with economic benefits to local businesses.
There will be some positive environmental aspects as well, according to Turner.
Once a dam is removed, the water will once again take on natural characteristics of a free flowing river system. “We expect to see the return of many mussel species, some endangered, especially within the upper eight miles of the former pool of Dam 6.” said Turner.
Without the dam, there will be elimination of unnatural water levels within a large part of the Mammoth Cave and improvement of riverine habitats for aquatic organisms including endangered mussels, darters and sport fishes such as smallmouth bass and muskellunge.
The Green River is one of the most biodiverse rivers in the country. It is home to more than 150 fish species, more than 70 mussel species and many threatened or endangered species.
“The thing that stood out to me is that everybody played their role and the mechanisms were in place to remove the dam,” said Lee Andrews, state field office supervisor, U.S. Department of Fish and Wildlife Service. Federal legislation was signed in December of 2016 deauthorizing the dam from the Corps inventory and directing its removal.
The lock and dam was built in 1904-1905 and put into operation in 1906. The Corps closed the project in August 1951.