Falls of the Ohio National Wildlife Conservation Area

Falls of the Ohio National Wildlife Conservation Area
Fossil formations at the shores of the Ohio River in Clarksville
Location	Indiana, Kentucky
Nearest city	Louisville, Kentucky
Coordinates	38°16′36″N 85°45′56″W / 38.27665°N 85.76544°W / 38.27665; -85.76544Coordinates: 38°16′36″N 85°45′56″W / 38.27665°N 85.76544°W / 38.27665; -85.76544
Established	1981
U.S. National Natural Landmark
Designated	1966

The Falls of the Ohio National Wildlife Conservation Area is a national, bi-state area on the Ohio River near Louisville, Kentucky in the United States, administered by the U.S. Army Corps of Engineers. Federal status was awarded in 1981. The falls were designated a National Natural Landmark in 1966.^[1]

Overview

An early map of the Falls of the Ohio; Louisville, Kentucky is in the lower right

The area is located at the Falls of the Ohio, which was the only navigational barrier on the river in earlier times. The falls were a series of rapids formed by the relatively recent erosion of the Ohio River operating on 386-million-year-old Devonian hard limestone rock shelves. Louisville, Kentucky, and the associated Indiana communities—Jeffersonville, Clarksville, and New Albany—all owe their existence as communities to the falls, as the navigational obstacles the falls presented meant that late-18th-century and early- to late-19th-century river traffic could benefit from local expertise in navigating the 26-foot (7.9 m) drop made by the river over a distance of two miles (3 km). In its original form, the falls could be characterized more as rapids extending over a length of the river, than as a point-like discontinuity in a river such as Niagara Falls. Still, the falls provided a singular, dramatic and daunting obstacle to navigation on this important inland waterway.

The first locks on the river, the Louisville and Portland Canal completed in 1830, were built within a bypass canal constructed to provide year-round navigation of the river. The falls were later largely covered by the McAlpine Locks and Dam, built by the Army Corps of Engineers. The taming of the Ohio River at the falls, with the attendant reduction in local flow velocity has of late led to the covering over of the fossil beds by large and increasing quantities of low-velocity effluvia: although an impediment to viewing of the fossils, this action serves to protect the portions of the falls covered over by sediment and therefore temporarily immune to direct weathering. However, a significant area of the fossil-rich Devonian limestone rock is still left exposed, and is accessible to visitors today. The best time for visitation is during the low water season of the Ohio River between August and October. Removal of fossils is prohibited.

The shallowness of the falls provided a favored crossing point for bison in pre-settlement times and, later, an easy crossing for Native Americans.

In 1990, a section of the area in Indiana became the Falls of the Ohio State Park. An interpretive center is open throughout the year.

Size and sound

Prior to modification, for industrial and navigational purposes, the Falls of the Ohio spanned the entire width of the Ohio River. Native Americans and early European explorers heard the crisp roar of the Ohio River crashing down the cascade falls more than 10 miles away.^[2]

Geology

Large rugose coral (above hammer) in the Devonian Jeffersonville limestone at the Falls of the Ohio, near Louisville, Kentucky

The rock unit in which the falls are formed is referred to as the Jeffersonville limestone. The limestone formed approximately 387 to 380 million years ago during the Emsian Age (in the latest part of the Early Devonian Period) and the Eifelian Age (Middle Devonian). The exposure is unique—large and diverse tabulate corals and rugose corals are exposed in lifelike positions. Brachiopods and bryozoans are also present, as are gastropods (snails).

During the Devonian Period, the region lay at the bottom of a shallow inland sea about ten degrees north of the equator in the supercontinent of Euramerica.

See also

• Geography of Louisville, Kentucky
• History of Louisville, Kentucky
• List of attractions and events in the Louisville metropolitan area

References

External links

• Falls of the Ohio State Park
• Falls of the Ohio Archaeological Society
• Falls of the Ohio (U.S. Army Corps of Engineers). Retrieved 29 April 2017
• Jeffery. "The Falls of the Ohio (mostly maps & diagram. For history buff only)". UrbanOhio.com. Retrieved 28 April 2017.
• Hendricks, R. Todd; Phelps, Daniel J.; Ettensohn, Frank R.; Weems, George; Lundquist, Judy (2005). Silurian and Devonian Geology and Paleontology at the Falls of the Ohio, Kentucky/Indiana (PDF). Lexington, Kentucky: Kentucky Section of the American Institute of Professional Geologists. Retrieved 28 April 2017.
• Greb, Stephen F.; Hendricks, Richard Todd; Chesnut, Donald R. Jr. (1993). Fossil Beds of the Falls of the Ohio [Series XI, Special Publication 19] (PDF). Lexington, Kentucky: Kentucky Geological Survey. Retrieved 28 April 2017.
• Plat of the Falls of the Ohio at extreme low water (surveyed by Capt. T.J. Cram, Summer 1843)
• Cram, T. J. (March 21, 1844). "A copy of the report of Captain T.J. Cram, on the best mode of improving the navigation of the Ohio river at the falls at Louisville". Congressional Serial Set. 434 (28th Congress, 1st session: Senate document 243). Retrieved 29 April 2017.
• Johnson, Leland R.; Parrish, Charles E. (2007). Triumph at the Falls: The Louisville and Portland Canal (PDF). Louisville, Kentucky: Louisville District, U.S. Army Corps of Engineers. Retrieved 28 April 2017.