| Fast Facts |
location
80 miles south of Louisville
ecoregion
Interior Low Plateau
project size
1,500 square miles
public lands
Mammoth Cave National Park
partners
Kentucky Department of Natural Resources, U.S. Army Corps of Engineers, U.S. Department of Agriculture, local communities
conservancy initiatives
Freshwater
natural events
colorful darters spawn, April–May | |
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Two aquatic underworlds—one under ground, the other under water—depend on the natural flows of water borne by the Green River. |
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Above the Green River.
© William Neill/Larry Ulrich Stock |
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The land of south-central Kentucky rolls and dips, betraying a labyrinth of caves and sinkholes just below the surface. Underneath the dimpled farm fields and woods lies a vast karst system whose Mississippian limestones were laid down more than 300 million years ago by a shallow saltwater sea. Mammoth Cave—national park, World Heritage Site and longest cave system in the world—offers a legendary entrance to this subterranean world of marine fossils and strange aquatic creatures like troglobites and sightless crayfish.
The Green River is the lifeblood of the cave ecosystem, its flows bearing food and sediment. Aptly named, the Green meanders between mossy limestone banks and tangles of sycamore, river birch and box elder. Vines of Virginia creeper hang close to the water, further deepening the green hue. Beneath the surface is a colorful world of aquatic diversity. Nearly 150 species of fish—more than in all of Europe—and 70 species of mussels make the Green the fourth-most biologically diverse river in the world. |
Drapery Room,
Mammoth Cave National Park.
© William Neill/Larry Ulrich Stock |
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The life forms that gather on the river’s rocky shoals and ply its clear waters have been increasingly threatened since 1969, when the Green River’s seasonal floods were tamed behind the concrete wall of the Green River Dam. Today seven species of mussels are federally listed as endangered; fish and crayfish have been hurt as well. Because the dam releases too little water in spring and more |
| water in fall than would have coursed downstream in an undammed river, the Green’s natural flows are out of balance and the ecosystem’s health has faltered. | |
In 1999 The Nature Conservancy went to the source of that ecological stress: the U.S. Army Corps of Engineers, the dam’s operator. Their discussions led to an agreement by which the Army Corps will modify its water releases from the dam to improve the ecological health of the river. The agreement in turn engendered a similar national-level cooperative partnership between the Conservancy and the Army Corps.
Learn more about The Nature Conservancy's work in Kentucky. |
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| Conservation Profile |
targets
river flows, karst systems, mussels like the clubshell and ring pink, fish like the spotted darter and splendid darter, Indiana and gray bats, bottlebrush crayfish
stresses
altered hydrological regime, sedimentation from agricultural practices, incompatible rural development
strategies
modify dam operations, restore ecosystems, secure conservation easements, encourage conservation management of private land
results
agreement with Army Corps of Engineers secures ecologically compatible water releases from the Green River Dam | | | | |
