Calderwood Dam
Encyclopedia
Calderwood Dam is a hydroelectric dam located along the Little Tennessee River
in Blount
and Monroe counties, Tennessee
. Completed in 1930, the dam is owned and maintained by Tapoco
, a subsidiary of the Aluminum Company of America (Alcoa), although the Tennessee Valley Authority
controls the dam's reservoir levels from Fontana Dam
further upstream. Calderwood Dam is named for Alcoa engineer Isaac Glidden Calderwood (1871–1941), who supervised much of the company's early Little Tennessee River operations.
Calderwood Dam was one of four dams— along with Cheoah
, Santeetlah
, and Chilhowee
— built in the Little Tennessee Valley by Alcoa in the 20th century to provide electricity to its aluminum smelting operations in Blount County. The dam was one of the last to be completed in the Tennessee River watershed before TVA took control of the watershed in 1933. Alcoa developed the community of Calderwood, Tennessee
, just downstream from the dam to house construction and maintenance crews for its Little Tennessee Valley operations. In 1989, Calderwood Dam was placed on the National Register of Historic Places
. The listing was expanded in 1990 and again in 2004 to include most of the dam's substructures.
. The area is surrounded by mountains on all sides, with the Great Smoky Mountains
rising to the north and the Unicoi Mountains rising to the south. U.S. Route 129
runs roughly parallel to the Blount County side of the river, providing the only major road access to the Calderwood area.
The Calderwood complex graces a horseshoe bend in the river known as "The Narrows." The dam is located along the upstream end of this bend, and the powerhouse, service building, and old Calderwood community (now a recreation area) are located along the downstream end of this bend. The service building, recreation area, and historical community structures are accessible via Housley Road (gated at night), which connects US-129 to Growdon Road at the service building. Growdon Road continues past the service building to the powerhouse, although this section of the road is only publicly open to foot traffic. The Calderwood Overlook, located along US-129 just south of the road's intersection with Housley Road, provides a sweeping view of the Calderwood Reservoir. A gravel road, also open only to public foot traffic, connects the overlook to Calderwood Dam.
Calderwood's powerhouse is located 1.2 miles (1.9 km) downstream from the dam, on the opposite side of the horseshoe bend in the river. A submerged intake just upstream from the dam diverts water into a 2150 feet (655.3 m) concrete tunnel, which carries the water to the other side of the peninsula, where it spills down three penstock
s to a valvehouse. The penstocks measure approximately 18 feet (5.5 m) in diameter, and range in length from 330 feet (100.6 m) to 388 feet (118.3 m). The valve house is built of steel-reinforced concrete, and is equipped with three Francis turbine
s. The powerhouse, a larger brick structure adjacent to the valvehouse, is equipped with three Westinghouse generators with a combined capacity of 140.4 megawatts. The powerhouse complex, located adjacent to a rockslide-prone cliffslope, is protected by a V-shaped reinforced concrete wall.
Calderwood's reservoir covers approximately 570 acres (230.7 ha) with a drainage area of 1856 mi2. The elevation of Calderwood Reservoir is 1087.8 feet (USGS), and the reservoir covers an 8 miles (12.9 km) stretch of the river. About half of Calderwood Reservoir lies in Tennessee, with the remainder extending into North Carolina
.
The "cushion pool" design of Calderwood was influenced by natural cascade waterfall formations. The dam's arched-crest design may have been influenced by the design of Ocoee Dam No. 1
, which was completed in 1911 along the Ocoee River a few miles to the south. Calderwood's use of a conduit tunnel to carry water to a powerhouse further downstream resembles the Great Falls Dam complex, completed in 1916 on the Caney Fork in Middle Tennessee
.
The community of Calderwood, Tennessee, located downstream from the dam and powerhouse, was developed in 1912 to house construction crews for Alcoa's Little Tennessee projects. This community was initially known as "Alcoa," but its name was changed to "Calderwood" in 1920 when the company reapplied its name to its main company town north of Maryville
. The Calderwood community grew to include nearly two dozen houses, two churches, a school, and a theater, but as construction and maintenance crews were no longer needed, the community was largely abandoned in the 1950s. Its houses were all razed, but the school and theater (now used as storage) were added to Calderwood Dam's National Register listing in 2004.
Little Tennessee River
The Little Tennessee River is a tributary of the Tennessee River, approximately 135 miles long, in the Appalachian Mountains in the southeastern United States.-Geography:...
in Blount
Blount County, Tennessee
Blount County is a U.S. county located in the U.S. state of Tennessee. Its population was 123,010 at the United States Census, 2010. The county seat is at Maryville, which is also the county's largest city....
and Monroe counties, 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...
. Completed in 1930, the dam is owned and maintained by Tapoco
Tapoco
Tapoco, originally Tallassee Power Company, is a generator and supplier of electric power. Tapoco is a division of APGI which in turn is owned by ALCOA Inc. The Tapoco Project serves to generate and supply hydroelectric power to ALCOA’s Tennessee Operations, an aluminum smelting and rolling mill...
, a subsidiary of the Aluminum Company of America (Alcoa), although 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...
controls the dam's reservoir levels from Fontana Dam
Fontana Dam
Fontana Dam is a hydroelectric dam on the Little Tennessee River in Swain and Graham counties, North Carolina, USA. The dam is operated by the Tennessee Valley Authority, which built the dam in the early 1940s to accommodate the skyrocketing electricity demands in the Tennessee Valley at the...
further upstream. Calderwood Dam is named for Alcoa engineer Isaac Glidden Calderwood (1871–1941), who supervised much of the company's early Little Tennessee River operations.
Calderwood Dam was one of four dams— along with Cheoah
Cheoah Dam
The Cheoah Dam is a hydroelectric complex located in Graham and Swain counties, North Carolina on the Little Tennessee River between river miles 51 and 52. The Cheoah Development consists of a dam and powerhouse, the first of several constructed by the Tallassee Power Company, now Tapoco...
, Santeetlah
Santeetlah Dam
Santeetlah Dam is a hydroelectric development on the Cheoah River in Graham County, North Carolina. The dam together with a pipeline/tunnel facility, and a powerhouse form the Santeetlah Development...
, and Chilhowee
Chilhowee Dam
Chilhowee Dam is a hydroelectric dam located in Blount and Monroe counties, Tennessee, between river mile 33 and 34 on the Little Tennessee River. Construction began in 1955 and was completed in 1957. The dam's reservoir covers approximately at normal full pool and has a drainage area of . The...
— built in the Little Tennessee Valley by Alcoa in the 20th century to provide electricity to its aluminum smelting operations in Blount County. The dam was one of the last to be completed in the Tennessee River watershed before TVA took control of the watershed in 1933. Alcoa developed the community of Calderwood, Tennessee
Calderwood, Tennessee
Calderwood was a community once located along the Little Tennessee River in Blount County, Tennessee, USA. Established in 1912 as a base for the Aluminum Company of America's Little Tennessee Valley hydroelectric development operations, the community continued to house construction personnel and...
, just downstream from the dam to house construction and maintenance crews for its Little Tennessee Valley operations. In 1989, Calderwood Dam was placed on the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
. The listing was expanded in 1990 and again in 2004 to include most of the dam's substructures.
Location
Calderwood Dam is located approximately 44 miles (70.8 km) upstream from the mouth of the Little Tennessee River, which flows westward from North Carolina and empties into 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...
. The area is surrounded by mountains on all sides, with the Great Smoky Mountains
Great Smoky Mountains
The Great Smoky Mountains are a mountain range rising along the Tennessee–North Carolina border in the southeastern United States. They are a subrange of the Appalachian Mountains, and form part of the Blue Ridge Physiographic Province. The range is sometimes called the Smoky Mountains or the...
rising to the north and the Unicoi Mountains rising to the south. U.S. Route 129
U.S. Route 129
U.S. Route 129 is an offshoot route of U.S. Route 29, which it intersects near Athens, Georgia. US 129 currently runs for 582 miles from Knoxville, Tennessee, to Chiefland, Florida, at U.S. Route 19 and U.S. Route 98. It passes through the states of Tennessee, North Carolina, Georgia and Florida...
runs roughly parallel to the Blount County side of the river, providing the only major road access to the Calderwood area.
The Calderwood complex graces a horseshoe bend in the river known as "The Narrows." The dam is located along the upstream end of this bend, and the powerhouse, service building, and old Calderwood community (now a recreation area) are located along the downstream end of this bend. The service building, recreation area, and historical community structures are accessible via Housley Road (gated at night), which connects US-129 to Growdon Road at the service building. Growdon Road continues past the service building to the powerhouse, although this section of the road is only publicly open to foot traffic. The Calderwood Overlook, located along US-129 just south of the road's intersection with Housley Road, provides a sweeping view of the Calderwood Reservoir. A gravel road, also open only to public foot traffic, connects the overlook to Calderwood Dam.
Design
Calderwood Dam is a thin-section concrete structure 232 feet (70.7 m) high and 916 feet (279.2 m) wide,, and has a 24-gate arched-crest spillway. A 40 feet (12.2 m) lower-gravity "cushion" dam is located 370 feet (112.8 m) downstream from the main dam, creating a pool of water that protects the riverbed. The pool's effectiveness is enhanced by a deflection unit at the base of the main dam.Calderwood's powerhouse is located 1.2 miles (1.9 km) downstream from the dam, on the opposite side of the horseshoe bend in the river. A submerged intake just upstream from the dam diverts water into a 2150 feet (655.3 m) concrete tunnel, which carries the water to the other side of the peninsula, where it spills down three penstock
Penstock
A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydraulic turbines and sewerage systems. It is a term that has been inherited from the technology of wooden watermills....
s to a valvehouse. The penstocks measure approximately 18 feet (5.5 m) in diameter, and range in length from 330 feet (100.6 m) to 388 feet (118.3 m). The valve house is built of steel-reinforced concrete, and is equipped with three Francis turbine
Francis turbine
The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....
s. The powerhouse, a larger brick structure adjacent to the valvehouse, is equipped with three Westinghouse generators with a combined capacity of 140.4 megawatts. The powerhouse complex, located adjacent to a rockslide-prone cliffslope, is protected by a V-shaped reinforced concrete wall.
Calderwood's reservoir covers approximately 570 acres (230.7 ha) with a drainage area of 1856 mi2. The elevation of Calderwood Reservoir is 1087.8 feet (USGS), and the reservoir covers an 8 miles (12.9 km) stretch of the river. About half of Calderwood Reservoir lies in Tennessee, with the remainder extending into North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
.
History
Alcoa began developing the Little Tennessee Valley in 1909 to provide the enormous amounts of electricity needed to power to its aluminum smelting operations in Blount County. Superintendent I.G. Calderwood oversaw the extension of a railway line from Chilhowee to what is now Calderwood (railroad bridge support columns are still visible in the river just downstream from the dam). Southern Railway engineers had suggested that the construction of this rail line would take six months, but Calderwood and his team accomplished the task in just six weeks. The first of Alcoa's Little Tennessee Valley dams, Cheoah, was completed in 1919, and the second, Santeetlah, was completed in 1928. Preliminary work on Calderwood Dam began in 1918, but test drilling suggested the site might not be satisfactory. Subsequent tests confirmed the site's stability, however, and construction began in 1927. The first two generating units went into operation on June 22, 1930, and a third unit was added in 1938.The "cushion pool" design of Calderwood was influenced by natural cascade waterfall formations. The dam's arched-crest design may have been influenced by the design of Ocoee Dam No. 1
Ocoee Dam No. 1
Ocoee Dam Number 1 is a hydroelectric dam on the Ocoee River in Polk County in the U.S. state of Tennessee. The dam impounds the Parksville Reservoir , and is the farthest downstream of four dams on the Toccoa/Ocoee River owned and operated by the Tennessee Valley Authority. Completed in 1911,...
, which was completed in 1911 along the Ocoee River a few miles to the south. Calderwood's use of a conduit tunnel to carry water to a powerhouse further downstream resembles the Great Falls Dam complex, completed in 1916 on the Caney Fork in Middle Tennessee
Middle Tennessee
Middle Tennessee is a distinct portion of the state of Tennessee, delineated according to state law as the 41 counties in the Middle Grand Division of Tennessee....
.
The community of Calderwood, Tennessee, located downstream from the dam and powerhouse, was developed in 1912 to house construction crews for Alcoa's Little Tennessee projects. This community was initially known as "Alcoa," but its name was changed to "Calderwood" in 1920 when the company reapplied its name to its main company town north of Maryville
Alcoa, Tennessee
Alcoa is a city in Blount County, Tennessee, United States, south of Knoxville. Its population was 7,744 at the 2000 census. It is part of the Knoxville, Tennessee Metropolitan Statistical Area....
. The Calderwood community grew to include nearly two dozen houses, two churches, a school, and a theater, but as construction and maintenance crews were no longer needed, the community was largely abandoned in the 1950s. Its houses were all razed, but the school and theater (now used as storage) were added to Calderwood Dam's National Register listing in 2004.
External links
- Calderwood Dam — TVA site
- Calderwood Lake — Tennessee Wildlife Resources Agency official site