Kentucky Dam - Background and Construction

Background and Construction

Throughout the 19th century, Congress passed a series of initiatives to improve navigation on the Tennessee River between the river's mouth and Florence, Alabama. By the 1890s, a 5-foot (1.5 m) continuous channel had been secured, but was still deemed insufficient for major river traffic. The U.S. Army Corps of Engineers conducted an extensive survey of the lower river in the early 1900s, and recommended constructing a dam at Aurora Landing (roughly 20 miles (32 km) above the present site), but the project was never funded. In the 1930s, the Tennessee Valley Authority sought to create a continuous minimum 9-foot (2.7 m) channel along the entirety of the river from Paducah to Knoxville. The Authority also sought to help control flooding on the lower Mississippi River, especially in the aftermath of the Ohio River flood of 1937, as research had shown that 4% of the water in the lower Mississippi originates in the Tennessee River watershed. TVA surveyed the lower part of the river and considered the Aurora Landing site, but eventually settled on the present site at river mile 22.4. The Kentucky Dam project was authorized May 23, 1938, and construction began July 1, 1938.

The construction of Kentucky Dam and its reservoir required the purchase 320,244 acres (129,598 ha) of land, 48,496 acres (19,626 ha) of which had to be cleared. 2,609 families, 3,390 graves, and 365 miles (587 km) of roads had to be relocated. 65 new bridges were built, 7 were rebuilt, and 3 were raised. The Illinois Central Railroad— which crossed a bridge just downstream from the dam— was rerouted to cross the top of the dam. The communities of Johnsonville and Springville in Tennessee and Birmingham in Kentucky were completely inundated, and a protective dike was constructed at Big Sandy, Tennessee to protect the town from reservoir backwaters.

Kentucky Dam was completed and its gates closed on August 30, 1944, and its first generator went online September 14, 1944. The project cost nearly $118 million, making it the most expensive TVA dam project. Kentucky Dam's navigation lock was the first lock designed by TVA— the Corps of Engineers had designed the locks for previous TVA dam projects. The Corps of Engineers is designing the new lock, however, which was scheduled for completion in 2008.

Since Kentucky Dam is located in the New Madrid Seismic Zone — which produced earthquakes of estimated magnitude 7.0 to 7.9 in 1811 — it is one of the few TVA dams built to withstand major earthquake shocks. Emergency preparedness officials in Marshall County and McCracken County, Kentucky (downstream from the dam) and a TVA spokesman discussed concerns of the public about the dam in 2005 in a local newspaper, The Paducah Sun. The dam was regarded as well maintained. Experts suggested that any dam failure would probably occur in the earthen levees at the end of the concrete portion of the dam, and the subsequent release would start small and enlarge as water poured through it. It is not expected that a 50-foot (15 m) wall of water would suddenly go down the river. Instead, it would likely take at least six hours for the water level to rise above the Calvert City chemical plants. The floodwater should only reach the base of the Paducah floodwall.

The dam also carried a railroad line and two lanes of US 62/641 at its crest. However, due to the planned lock expansion, two new crossings were built just downstream of the dam—a two-lane road bridge and a separate rail bridge. The new bridges were opened in late 2009.