South Holston Dam is a hydroelectric and flood control dam on the

South Fork Holston River The Holston River is a river that flows from Kingsport, Tennessee, to Knoxville, Tennessee. Along with its three major forks (North Fork, Middle Fork and South Fork), it comprises a major river system that drains much of northeastern Tennessee ...

in Sullivan County, in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

. It is the uppermost of three dams on the South Fork Holston owned and operated by the

Tennessee Valley Authority The Tennessee Valley Authority (TVA) is a federally owned electric utility corporation in the United States. TVA's service area covers all of Tennessee, portions of Alabama, Mississippi, and Kentucky, and small areas of Georgia, North Carolin ...

, which built the dam in the 1940s as part of efforts to control flooding in the

Tennessee River The Tennessee River is the largest tributary of the Ohio River. It is approximately long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other name ...

watershed. On October 21, 1950 the valve gate closed and water began backing up to create South Holston Reservoir. Work began on the dam in December 1941, but in November 1942, the War Production Board requested that the operation be suspended because of a shortage of critical materials. Work did not resume until July 1, 1947. The dam now impounds the

South Holston Lake South Holston Lake is located near the cities of Abingdon, Virginia and Bristol, Virginia / Bristol, Tennessee, and is a impoundment operated by the Tennessee Valley Authority (TVA). Much of the reservoir is in Tennessee, but the Virginia portio ...

of , which extends northeastward across the Tennessee-

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

state line.Tennessee Valley Authority, ''The Upper Holston Projects: Watauga, South Holston, Boone, and Fort Patrick Henry; a Comprehensive Report on the Planning, Design, Construction, Initial Operations, and Costs of Four Hydro Projects in the Holston Basin at the Eastern Tip of Tennessee'', Technical Report No. 14 (Washington, D.C.: U.S. Government Printing Office, 1958), pp. 1-6, 12-18, 23, 31, 52-55, 168.

Location

South Holston Dam is located above the South Fork Holston River's confluence with the

North Fork Holston River The Holston River is a river that flows from Kingsport, Tennessee, to Knoxville, Tennessee. Along with its three major forks (North Fork, Middle Fork and South Fork), it comprises a major river system that drains much of northeastern Tennessee, ...

(which forms the

Holston River The Holston River is a river that flows from Kingsport, Tennessee, to Knoxville, Tennessee. Along with its three major forks (North Fork, Middle Fork and South Fork), it comprises a major river system that drains much of northeastern Tennessee, ...

proper). The dam site is situated in an area where the river descends out of the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...

and enters the upper Holston Valley. The dam and the Tennessee half of its reservoir are surrounded by the

Cherokee National Forest The Cherokee National Forest is a United States National Forest located in the U.S. states of Tennessee and North Carolina that was created on June 14, 1920. The forest is maintained and managed by the United States Forest Service. It encompasse ...

, and the Virginia half of the reservoir is surrounded by the

Jefferson National Forest The George Washington and Jefferson National Forests is an administrative entity combining two U.S. National Forests into one of the largest areas of public land in the Eastern United States. The forests cover of land in the Appalachian Mountai ...

. The reservoir includes parts of Sullivan County in Tennessee and Washington County in Virginia. The city of

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...

straddles the Tennessee-Virginia border a few miles northwest of South Holston Dam.

Capacity

South Holston Dam is an earth-and-rock dam high and long, and has a generating capacity of 38,500 kilowatts.Tennessee Valley Authority
South Holston Reservoir
Retrieved: 2 February 2009. The dam's fixed-crest

morning glory Morning glory (also written as morning-glory) is the common name for over 1,000 species of flowering plants in the family Convolvulaceae, whose current taxonomy and systematics are in flux. Morning glory species belong to many genera, some of ...

spillway has a maximum discharge of .Tennessee Valley Authority, ''The Nickajack Project: A Report on the Planning, Design, Construction, Initial Operations, and Costs'', Technical Report No. 16 (Knoxville, Tenn.: Tennessee Valley Authority, 1972), pp. 10-11. South Holston Lake extends northeastward for into southwestern Virginia, with of shoreline and a storage capacity of , of which is reserved for flood control. The reservoir's operating levels vary by about in a typical year. The dam has two intakes, one at the north end and one at the south end. The north intake transfers water from the reservoir via high-pressure conduit to the powerhouse at the northern base of the dam. The south intake feeds water into the dam's spillway, from which it travels through a sluiceway to a stilling basin at the southern base of the dam.

Background and construction

Various private entities had investigated the South Fork Holston's hydroelectric potential since the early 1900s, although other than

Wilbur Dam Wilbur Dam is a hydroelectric dam on the Watauga River in Carter County, in the U.S. state of Tennessee. It is one of two dams on the river owned and operated by the Tennessee Valley Authority. The dam impounds Wilbur Lake, which extends for abou ...

on the river's

Watauga River The Watauga River () is a large stream of western North Carolina and East Tennessee. It is long with its headwaters in Linville Gap to the South Fork Holston River at Boone Lake. Course The Watauga River rises from a spring near the base ...

tributary, no major projects had been initiated. In the 1920s, the Holston River Power Company conducted a massive survey of the South Fork Holston's watershed with plans to build four dams on the river, including one at the present South Holston Dam site. After the Tennessee Valley Authority gained oversight of the Tennessee River watershed in the following decade, it proposed the construction of two dams in the South Fork Holston basin— one at the South Holston Dam site and the other at Cardens Bluff (modern Watauga Dam). The primary purpose for building these two dams was flood control, especially in light of a disastrous flood in 1940 that had destroyed several structures in Bluff City and Kingsport, both downstream from the proposed dam sites. The dams would also produce electricity to help TVA meet the high demand for power at the outbreak of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. South Holston Dam and its sister project, Watauga Dam, were authorized on December 17, 1941, and work began on February 16 of the following year. The construction of South Holston Dam and its reservoir required the purchase of of land, of which had to be cleared. The construction moved 342 families and 559 graves. It required the relocation of of roads, and four new bridges were built. In October 1942, the U.S.

War Production Board The War Production Board (WPB) was an agency of the United States government that supervised war production during World War II. President Franklin D. Roosevelt established it in January 1942, with Executive Order 9024. The WPB replaced the Su ...

ordered a halt to the South Holston and Watauga projects, claiming they were not vital to the nation's war effort. TVA spent several weeks securing the dam sites, and the South Holston project was stalled until the end of the war. Work on South Holston began again on August 4, 1947, as Watauga neared completion. Along with the main dam, the South Holston project required the construction of a saddle dam approximately north of the main dam at the reservoir's Painter Spring embayment. The saddle dam is high and long. The project also necessitated the construction of an auxiliary spillway, since the main dam's morning glory spillway had not been adequately tested. This auxiliary spillway— known as the "Bent Branch Spillway" after the stream into which it empties— is located about south of the main dam. South Holston Dam was completed and its gates closed November 20, 1950. The dam's generator went online February 13, 1951. The total cost of the South Holston project was just over $31 million.

Weir Dam (1991)

In 1991, TVA built a weir dam, an aerating labrynth weir, approximately 1.5 miles below the main dam, straddling the midsection of Osceola Island. The weir helps to deal with the fact that the water coming out of the bottom of the dam is cold, dense, and oxygen depleted. The water also tends to have unpredictable recirculation currents. The weir counteracts these problems with the water out of the bottom of the dam. The weir oxygenates the water, which helps aquatic insects, vegetation, and fish—particularly bass and trout. The weir also prevents the water from refluxing back up to the turbine at the dam, and calms it down for recreational users such as those boating, fishing, and swimming.

References

External links

South Holston Reservoir
— official TVA site

— Tennessee Wildlife Resources Agency {{Tennessee Valley Authority Facilities Holston River Dams in Tennessee Tennessee Valley Authority dams Bristol, Tennessee Hydroelectric power plants in Tennessee Buildings and structures in Sullivan County, Tennessee Dams completed in 1950 Energy infrastructure completed in 1950 Tourist attractions in Sullivan County, Tennessee Tourist attractions in Bristol, Tennessee 1950 establishments in Tennessee