A dam is removed by heavy equipment.
Lock and Dam Removal Green River Lock and Dam #6 was removed in March, 2017. © Philip Scott Andrews

Stories in Kentucky

Freeing the Green River

Removing defunct dams restores natural flows and gives people and wildlife new opportunities to benefit from a healthy river.

Update on Green River Lock and Dam #5: Our partners at the U.S. Fish and Wildlife Service worked throughout the summer of 2021 on the removal of Lock and Dam #5. They made a lot of headway, demolishing the lock chamber, grading the area, and creating a pad behind the dam from which they will be able to remove the dam itself. Heavy rains and high water levels delayed progress, however, and the project is paused until spring 2022. We thank all of our partners for their hard work in making the largest dam removal in Kentucky history possible, and we look forward to more progress in the spring! More information is available in this U.S. Fish and Wildlife Service article.

The natural flow of a river resembles a healthy human heartbeat. Heavy rains send pulses of water downstream in spring, flushing out side channels and signaling fish to spawn. Dry stretches in summer allow seedlings to take root.

Dams and other man-made structures can change these rhythms. In fact, the beat of a heavily dammed river can look almost like a flatline. It causes natural systems to suffer.

A major conservation priority for the Kentucky chapter is restoring these natural systems by removing defunct locks and dams on the Green River. Lock and Dam #6 was removed in 2017 (see story below) and Lock and Dam #5 is being removed right now, in the summer of 2021. The removal will restore free-flowing conditions to 73 miles of the Green River, between the Rochester Dam and Pool 6. We know that these removals benefit aquatic species such as fish and mussels. The Green River is a biodiversity gem, with more than 150 fish species and 70 species of mussels, including 43 species existing nowhere else in the world. But did you know the removals also improve fishing, paddling, and local economies? 

Fish population surveys have clearly shown that the number and health of sportfish in free-flowing sections of the Green River are far superior to its impounded pools, so the fishery is expected to improve with the removal of Lock and Dam #5. The water contained in the pool upstream of a dam is more like a pond than a flowing river. Once the dam is removed, the water will once again take on the natural characteristics of a free-flowing river system, which will result in improved fishing for freshwater species like the smallmouth bass. 

Low-head dams such as Lock and Dam #5 also present safety hazards to people. Once the dam is gone, canoeists and kayakers will be able to safely paddle through the former location of the dam. Those visiting Mammoth Cave National Park will now be able to safely paddle past Brownsville, with no in-stream barriers between Mammoth Cave and the Rochester Dam. This will greatly benefit the ongoing Green River Blueway and Trail Town initiatives, which have been embraced by many small towns along the Green River and also by the Barren River Area Development District (BRADD).

People standing at a large dam in a river.
Green River Lock and Dam #5 This lock and dam are being removed in the summer of 2021. The removal will have great benefits for nature and people alike: A healthier river, safer river, and more accessible river. © Mike Wilkinson
A group of mussels rest on a sandy riverbank.
Green River Mussels A collection of mussels exposed during the breaching Lock and Dam #6 on the Green River in Kentucky. © Kentucky Department of Fish and Wildlife/Monte McGregor

The Removal of Lock and Dam 6

In Kentucky, the Spring of 2017 marked a time when the Green River reclaimed its heartbeat. That is when trained workers from the U.S. Fish and Wildlife Service (USFWS) dismantled Lock and Dam 6, an aging steel structure that had not fulfilled its original purpose to control flooding and support navigation since 1951. In addition to involvement by the USFWS, removing Lock 6 resulted from a cooperative effort led by The Nature Conservancy and its partners, including the U.S. Army Corps of Engineers; the Kentucky Department of Fish & Wildlife Resources; the Kentucky Tourism, Arts and Heritage Cabinet; Mammoth Cave National Park; and Kentucky Waterways Alliance.

Aerial image of dam removal, looking down on diggers that have partially removed a concrete dam from the river.
Lock and Dam Removal Green River Lock and Dam #6 was removed in March, 2017. © Philip Scott Andrews

Restoring Natural Flows

People have navigated Kentucky’s Green River for commerce since pioneer days. However, the Green’s natural pulse changed significantly circa 1900 with the advent of locks and dams built on the river and its tributaries—and eventually its headwaters—to aid in commercial navigation.

Eventually, the locks and dams caught the attention of TNC, leading the organization to approach the U.S. Army Corps of Engineers about operating these structures, and especially the Green River Lake Dam, in ways that better mimic the river’s natural flow patterns to support native wildlife while meeting demands for clean water and recreation. 

TNC’s request came after a scientific analysis revealed that, while water releases from the reservoir resembled natural flows during much of the year, they were up to six times higher and significantly colder than historic flows during the fall—a critical spawning time for many fish and mussels.

Historical black-and-white photo of cranes constructing the dam.
Dam Construction A November 1903 photo shows Green River Lock and Dam #6 being built. It opened for commercial navigation in 1906. © U.S. Army Corps of Engineers
Concrete dam with cracks and areas that are crumbling.
A Century Later A large crack forms in the dam in 2004. © Mammoth Cave National Park
Dam Construction A November 1903 photo shows Green River Lock and Dam #6 being built. It opened for commercial navigation in 1906. © U.S. Army Corps of Engineers
A Century Later A large crack forms in the dam in 2004. © Mammoth Cave National Park

The Sustainable Rivers Program

The introduction of more ecologically compatible flows to the dam helped launch the Sustainable Rivers Program, a collaborative effort to find more sustainable ways to manage river infrastructure to maximize benefits to people and nature. The program focuses on determining unique flow requirements for rivers and then creating operating plans for dams that achieve environmental flows—scientific prescriptions for the timing, quantity and quality of water flow that must occur downstream of dams in order to revive and sustain critical ecological functions and habitat for species. The SRP has been so successful that it has now expanded to 66 federal dams on 16 rivers in 15 states as of 2019. 

The Corps and TNC also began to examine five old locks and dams on the Green River and one on the Barren River. Mike Hensley, TNC's former Green River Project Director, describes the structures as, “old beasts—the oldest constructed in 1836—all showing signs of age and decline.” Hensley notes that removal of these dams is a win for both people and nature. In addition to the positive conservation outcomes, human safety is increased and river recreation improved, adding, “Removing these old, decaying structures, or carefully breaching them, will allow recreation enthusiasts to enjoy miles and miles of these rivers safely without the worry of being swept over a low-head dam.”

Yellow diggers sit mid-stream and remove debris from the river.
Lock and Dam Removal Green River Lock and Dam #6 was removed in March, 2017. © Philip Scott Andrews

Dam Removal Benefits People and Nature

In March 2017, TNC and its partners transformed planning into action with the permanent removal of Lock and Dam 6. This bold move was made possible by passage of the Water Infrastructure Improvements for the Nation (WIIN) Act of 2016, which included language de-authorizing four locks and dams on the Green River and one on the Barren River.

“The Conservancy played a major role in building support for the legislation among stakeholders, and Senator Mitch McConnell and Representative Brett Guthrie proved instrumental in getting the bill passed,” says David Phemister, TNC’s State Director in Kentucky.

The legislation directs the U.S. Amy Corps of Engineers to transfer ownership of the locks and dams, and associated acreage, to various state and local entities, in several cases for the specific purpose of removing the structures from the river.

Phemister adds, “This is a huge step forward in our efforts to make the Green River healthier, safer and more valuable for a growing outdoor recreation economy.”

Aerial Video of Green River Lock and Dam Removal (3:09) Watch this video from the Edmondson Voice showing the dam removal process and learn more about Green River Lock and Dam #6.

In addition to new outdoor recreation opportunities, removing Lock and Dam 6 and other aging structures will yield conservation benefits for the entire Green River system. Allowing for a more fully functional watershed benefits wildlife, including one of the most diverse assemblages of freshwater mussels in the world—species which serve as natural filters for these waters that provide drinking water to the local community.

Hensley says, “Removing this infrastructure from federal ownership presents an enormous opportunity to secure water supply, economic, recreation and conservation wins for the region. I look forward to what lies ahead."

Looking Ahead

TNC and its partners are now preparing to remove Lock and Dam #5, about 14 miles downstream from the site of the former Lock and Dam #6. This  process includes gathering data that will shape and inform a feasibility analysis and, eventually, the removal of the dam.