Appalachian History Series
Setting the Scene
On the South Fork Holston River just southeast of Bristol, Tennessee, the Tennessee Valley Authority built South Holston Dam to curb destructive flooding and to supply hydropower in the mid-twentieth century. The project impounded a long, slender reservoir that reaches about 24 miles into Virginia, and it became the upstream anchor of TVA’s Holston River system.
Why South Holston Was Built
TVA authorized the upper Holston projects during World War II as part of a regional plan to control floods and add generating capacity. Work began in 1942, paused later that year when the War Production Board diverted critical materials to higher-priority wartime needs, then resumed in 1947. TVA closed the gates on November 20, 1950, and synchronized the single generating unit on February 13, 1951. These dates come directly from TVA’s own historical account.
Building a Big Earthen Dam in the Southern Appalachians
South Holston is an earth and rockfill embankment about 285 feet high and 1,600 feet long. TVA’s design team paired the main structure with a fixed-crest morning-glory spillway and, as extra insurance for extreme floods, an auxiliary spillway on Bent Branch roughly a mile and a half to the south. The site also required a low saddle dam to contain the reservoir at a gap to the north. Contemporary TVA technical documentation and later dam safety compilations describe the Bent Branch feature and related hydraulics.
People Moved, Roads Rerouted, A Valley Flooded
TVA acquired thousands of acres, cleared bottomland and timber, relocated families and cemeteries, and rebuilt roads and bridges to make way for the lake. Those social costs, familiar across the Valley in this era, accompanied the promise of flood protection and electric power.
Power on the Grid, Water Under Control
Once online in February 1951, South Holston joined an integrated TVA cascade that regulates the South Fork Holston for several purposes. The lake stretches about 24 miles and provides seasonal storage that can be held and released to reduce downstream flood peaks and to support power production, navigation, and water quality. TVA’s operating pages still summarize these multi-use goals for the project today.
An Innovation Downstream: The Labyrinth Weir
In 1991 TVA installed a low labyrinth weir about a mile and a half below the dam. The weir raises and aerates the tailwater between turbine releases, which increases dissolved oxygen for aquatic life and smooths out flow for boaters and anglers. TVA credits the weir with helping to sustain a nationally known wild brown trout fishery in the tailwater.
What South Holston Means to the Region
For the communities of northeast Tennessee and southwest Virginia, the dam has meant fewer ruinous floods, dependable electricity, and a new recreation economy around the lake and tailwater fishery. That transformation arrived with real tradeoffs where homes and farms once stood. As the project passed from wartime start, to postwar completion, to modern environmental retrofits, it became part of the region’s historical landscape as surely as the ridgelines above it.
Sources and Further Reading
Tennessee Valley Authority, “South Holston,” overview and operating information. Tennessee Valley Authority
Tennessee Valley Authority, “Weir Science,” history and description of the 1991 labyrinth weir, with dates for construction, gate closure, and first power. Tennessee Valley Authority
U.S. Government Printing Office for TVA, The Upper Holston Projects: Watauga, South Holston, Boone, and Fort Patrick Henry (Technical Report No. 14, 1958). Bibliographic entry and archival references. Online Books PageGoogle BooksNational Archives
U.S. NRC document set, “Dam Rating Curves, South Holston,” including figures referencing the Bent Branch auxiliary spillway. NRC Web
U.S. Government, Audit Report of Tennessee Valley Authority for the fiscal year 1951 noting addition of South Holston in February 1951. GovInfo
South Holston Dam general summary. Wikipedia
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