Great Falls Dam
Encyclopedia
Great Falls Dam is a hydroelectric dam on the Caney Fork, straddling the county line between White County
and Warren County in the U.S. state of Tennessee
. It is the only dam outside the Tennessee River
watershed owned and operated by the Tennessee Valley Authority
. The dam impounds the 1830 acres (740.6 ha) Great Falls Lake, and its tailwaters feed into Center Hill Lake
. The completion of Great Falls Dam in 1917 was an engineering triumph, marking the first successful attempt to impound the volatile and flood-prone Caney Fork. The dam is also notable for its design, utilizing a mostly-underground conduit to carry water from the reservoir via a tributary to the Power House 0.75 miles (1.2 km) downstream from the dam.
Great Falls Dam is named for the rapids and waterfalls on the Caney Fork downstream from the dam. The section of river below the Power House is world-renowned for whitewater kayaking
. The dam and its tailwaters are surrounded by Rock Island State Park
.
. The confluence of these two rivers (the Collins flowing from the southwest and the Caney Fork from the east) creates a peninsula. The two rivers nearly meet at the Narrows a "land bridge" connecting the peninsula to the mainland. Two tunnels deliver water from the Collins River section of the Great Falls Reservoir to the dam's Power House located on the Caney Fork 0.75 miles (1.2 km) downstream from the dam.
Great Falls Reservoir stretches behind the dam for 22 miles (35.4 km) along the Caney Fork and for roughly 10 miles (16.1 km) along the lower Collins River. The lake also includes a small stretch of the lower Rocky River
, which empties into the Caney Fork about a mile east of the dam.
Throughout the 19th century, entrepreneur after entrepreneur attempted to harness the extraordinary hydro power potential of the Caney Fork only to be defeated by one of the volatile river's disastrous floods. The first major establishment to utilize the river's power at Great Falls was the Bosson Mill, a gristmill
and carding
factory that operated at the site across the river from the Power House from the 1860s until its destruction by a flood in 1882. The most prominent venture at Great Falls Gorge was the Falls City Cotton Mill Company, which established a cotton mill and company town, Falls City, just above the gorge in 1892. The company turned a moderate profit until 1902, when the Good Friday Flood destroyed its toll bridge and powerhouse, and the mill was forced to close (the mill and the town's "spring castle" are still standing, however).
By 1900, the rise of major industry in Nashville
brought an increased demand for electricity. In 1901, Nashville entrepreneur Arthur Dyer formed the Great Falls Power Company and purchased land on the north side of the gorge with plans to build a dam. Dyer had trouble getting financing for the project, however, and in 1912 sold Great Falls Power to the Tennessee Power Company. The original plans called for a dam 110 feet (33.5 m) high. At the "Narrows," where the two tunnels are now located, an open channel was to be made from the Collins River to the Caney Fork. The water was to be carried across the gorge in a steel flume and then in an open canal across Horseshoe Bend, a distance of 1.5 miles (2.4 km). The Power House was to be located at least 3 miles (4.8 km) by river below the present Power House. In so doing a total head of 235 feet (71.6 m) would have been available; 110 feet (33.5 m) at the dam, 75 feet (22.9 m) between the dam and the present Power House and 50 feet (15.2 m) around horseshoe bend. With financing from Chicago business interests, Tennessee Power began construction work on the dam's foundation. Within a month, however, the Caney Fork burst its banks again, flooding out the project's excavation work and destroying its cofferdam
s. Tennessee Power again struggled with finances, but was able to resume construction in 1915 and by late 1916, the 40 feet (12.2 m) high dam had been completed. The plant went into operation on January 1, 1917.
In 1922, the Tennessee Power Company merged with several other entities to form the Tennessee Electric Power Company (TEPCO). TEPCO tripled the capacity of Great Falls Dam by raising the dam 35 feet (10.7 m) and installing a second generator at the powerhouse downstream. The dam faced its first major test in March 1929, when several cloudburst
s atop the Cumberland Plateau
caused the Caney Fork to expand to record flood volumes, sending wreckage and uprooted trees crashing into the dam. The Great Falls Power House was flooded and a substation was destroyed, but the dam held.
watershed, where most of TEPCO's dams were located. Jo Conn Guild
, the head of TEPCO, vehemently opposed TVA and challenged the constitutionality of the TVA Act in federal court. After the U.S. Supreme Court
upheld the act, however, TEPCO was forced to sell its assets to TVA for $78 million. This sum included $3.5 million for Great Falls Dam.
After its acquisition, TVA almost immediately began making improvements to Great Falls Dam. By 1946, grouting work had repaired much of the leakage through the cliffside, which had been an issue since the dam's creation. TVA also built a new switchyard and control building. In the late 1960s, the agency leased part of the Great Falls reservation to the state of Tennessee for the development of Rock Island State Park, which opened in 1969.
White County, Tennessee
White County is a county located in the U.S. state of Tennessee. As of 2000, the population was 23,102. Its county seat is Sparta.-History:...
and Warren County in the U.S. state of Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
. It is the only dam outside the Tennessee River
Tennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately 652 miles 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 names...
watershed owned and operated by the Tennessee Valley Authority
Tennessee Valley Authority
The Tennessee Valley Authority is a federally owned corporation in the United States created by congressional charter in May 1933 to provide navigation, flood control, electricity generation, fertilizer manufacturing, and economic development in the Tennessee Valley, a region particularly affected...
. The dam impounds the 1830 acres (740.6 ha) Great Falls Lake, and its tailwaters feed into Center Hill Lake
Center Hill Lake
Center Hill Lake is a reservoir in the U.S. state of Tennessee. It is located in Middle Tennessee near Smithville. Created by means of a dam constructed by the U.S. Army Corps of Engineers in 1948, the lake had a dual purpose: electricity production and flood control...
. The completion of Great Falls Dam in 1917 was an engineering triumph, marking the first successful attempt to impound the volatile and flood-prone Caney Fork. The dam is also notable for its design, utilizing a mostly-underground conduit to carry water from the reservoir via a tributary to the Power House 0.75 miles (1.2 km) downstream from the dam.
Great Falls Dam is named for the rapids and waterfalls on the Caney Fork downstream from the dam. The section of river below the Power House is world-renowned for whitewater kayaking
Whitewater kayaking
Whitewater kayaking is the sport of paddling a kayak on a moving body of water, typically a whitewater river. Whitewater kayaking can range from simple, carefree gently moving water, to demanding, dangerous whitewater. River rapids are graded like ski runs according to the difficulty, danger or...
. The dam and its tailwaters are surrounded by Rock Island State Park
Rock Island State Park (Tennessee)
Rock Island State Park is a state park in Warren County and White County, Tennessee, located in the Southeastern United States. The park is named after the community of Rock Island, Tennessee, which in turn received its name from an island on the Caney Fork upstream from the Collins River...
.
Location
Great Falls Dam is located approximately 94 miles (151.3 km) above the mouth of the Caney Fork, immediately downstream from the Caney Fork's confluence with the Collins RiverCollins River
The Collins River is a tributary of the Caney Fork of the Cumberland River in the U.S. state of Tennessee. Via the Cumberland and Ohio rivers, it is part of the Mississippi River watershed....
. The confluence of these two rivers (the Collins flowing from the southwest and the Caney Fork from the east) creates a peninsula. The two rivers nearly meet at the Narrows a "land bridge" connecting the peninsula to the mainland. Two tunnels deliver water from the Collins River section of the Great Falls Reservoir to the dam's Power House located on the Caney Fork 0.75 miles (1.2 km) downstream from the dam.
Great Falls Reservoir stretches behind the dam for 22 miles (35.4 km) along the Caney Fork and for roughly 10 miles (16.1 km) along the lower Collins River. The lake also includes a small stretch of the lower Rocky River
Rocky River (Tennessee)
The Rocky River is a tributary of the Caney Fork of the Cumberland River in the U.S. state of Tennessee. Via the Caney Fork and the Cumberland and Ohio rivers, it is part of the Mississippi River watershed....
, which empties into the Caney Fork about a mile east of the dam.
Capacity
Great Falls Dam is a concrete gravity diversion type dam 92 feet (28 m) high and 800 feet (243.8 m) long, and has a generating capacity of 33,800 kilowatts. The dam's spillway has 18 gates with a combined discharge of 150000 cubic feet (4,247.5 m³) per second. Great Falls Reservoir has approximately 49000 acre.ft of flood storage, 120 miles (193.1 km) of shoreline, and 1830 acres (740.6 ha) of water surface.History
Gristmill
The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...
and carding
Carding
Carding is a mechanical process that breaks up locks and unorganised clumps of fibre and then aligns the individual fibres so that they are more or less parallel with each other. The word is derived from the Latin carduus meaning teasel, as dried vegetable teasels were first used to comb the raw wool...
factory that operated at the site across the river from the Power House from the 1860s until its destruction by a flood in 1882. The most prominent venture at Great Falls Gorge was the Falls City Cotton Mill Company, which established a cotton mill and company town, Falls City, just above the gorge in 1892. The company turned a moderate profit until 1902, when the Good Friday Flood destroyed its toll bridge and powerhouse, and the mill was forced to close (the mill and the town's "spring castle" are still standing, however).
By 1900, the rise of major industry in Nashville
Nashville, Tennessee
Nashville is the capital of the U.S. state of Tennessee and the county seat of Davidson County. It is located on the Cumberland River in Davidson County, in the north-central part of the state. The city is a center for the health care, publishing, banking and transportation industries, and is home...
brought an increased demand for electricity. In 1901, Nashville entrepreneur Arthur Dyer formed the Great Falls Power Company and purchased land on the north side of the gorge with plans to build a dam. Dyer had trouble getting financing for the project, however, and in 1912 sold Great Falls Power to the Tennessee Power Company. The original plans called for a dam 110 feet (33.5 m) high. At the "Narrows," where the two tunnels are now located, an open channel was to be made from the Collins River to the Caney Fork. The water was to be carried across the gorge in a steel flume and then in an open canal across Horseshoe Bend, a distance of 1.5 miles (2.4 km). The Power House was to be located at least 3 miles (4.8 km) by river below the present Power House. In so doing a total head of 235 feet (71.6 m) would have been available; 110 feet (33.5 m) at the dam, 75 feet (22.9 m) between the dam and the present Power House and 50 feet (15.2 m) around horseshoe bend. With financing from Chicago business interests, Tennessee Power began construction work on the dam's foundation. Within a month, however, the Caney Fork burst its banks again, flooding out the project's excavation work and destroying its cofferdam
Cofferdam
A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed...
s. Tennessee Power again struggled with finances, but was able to resume construction in 1915 and by late 1916, the 40 feet (12.2 m) high dam had been completed. The plant went into operation on January 1, 1917.
In 1922, the Tennessee Power Company merged with several other entities to form the Tennessee Electric Power Company (TEPCO). TEPCO tripled the capacity of Great Falls Dam by raising the dam 35 feet (10.7 m) and installing a second generator at the powerhouse downstream. The dam faced its first major test in March 1929, when several cloudburst
Cloudburst
A cloudburst is an extreme amount of precipitation, sometimes with hail and thunder, which normally lasts no longer than a few minutes but is capable of creating flood conditions.-Etymology:There are similar names for such events in other languages...
s atop the Cumberland Plateau
Cumberland Plateau
The Cumberland Plateau is the southern part of the Appalachian Plateau. It includes much of eastern Kentucky and western West Virginia, part of Tennessee, and a small portion of northern Alabama and northwest Georgia . The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the...
caused the Caney Fork to expand to record flood volumes, sending wreckage and uprooted trees crashing into the dam. The Great Falls Power House was flooded and a substation was destroyed, but the dam held.
TVA
The passage of the TVA Act in 1933 gave the Tennessee Valley Authority oversight of flood control operations in the Tennessee RiverTennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately 652 miles 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 names...
watershed, where most of TEPCO's dams were located. Jo Conn Guild
Jo Conn Guild
Josephus "Jo" Conn Guild, Jr. was an American businessman and engineer from Chattanooga, Tennessee. As president of the Tennessee Electric Power Company , he became one of the staunchest and most outspoken opponents of the newly formed Tennessee Valley Authority in the 1930s...
, the head of TEPCO, vehemently opposed TVA and challenged the constitutionality of the TVA Act in federal court. After the U.S. Supreme Court
Supreme Court of the United States
The Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases...
upheld the act, however, TEPCO was forced to sell its assets to TVA for $78 million. This sum included $3.5 million for Great Falls Dam.
After its acquisition, TVA almost immediately began making improvements to Great Falls Dam. By 1946, grouting work had repaired much of the leakage through the cliffside, which had been an issue since the dam's creation. TVA also built a new switchyard and control building. In the late 1960s, the agency leased part of the Great Falls reservation to the state of Tennessee for the development of Rock Island State Park, which opened in 1969.
External links
- Great Falls Reservoir — official TVA site
- Rock Island State Park — official site