Ocoee Dam No. 3
Encyclopedia
Ocoee Dam No. 3 is a hydroelectric dam on the Ocoee River in Polk County, in the U.S. state of Tennessee
. It is one of four dams on the Toccoa/Ocoee River owned and operated by the Tennessee Valley Authority
, which built the dam in the early 1940s to meet emergency demands for electricity during World War II
. The dam impounds the 360 acres (145.7 ha) Ocoee No. 3 Reservoir, which stretches 11 miles (17.7 km) upriver to the Tennessee-Georgia
state line. Ocoee No. 3's powerhouse is actually located several miles downstream from the dam, and is fed by a 2.5 miles (4 km) conduit that carries water to it from the reservoir.
to the south. Both of these mountains are protected by federal wilderness areas which are adjacent to TVA's Ocoee No. 3 reservation boundary. Ocoee Dam No. 2
is just 5 miles (8 km) downstream, and Blue Ridge Dam
is 23 miles (37 km) upstream. The Toccoa River, which flows down from its source in the Blue Ridge Mountains
of northern Georgia, enters Tennessee (where it becomes the Ocoee River) approximately 11 miles (17.7 km) upstream from Ocoee Dam No. 3, near the Copperhill
area. The Ocoee Scenic Byway— which is part of U.S. Route 64
— passes just north of the dam.
Ocoee Dam No. 3 is a concrete gravity diversion-type dam 110 feet (33.5 m) high and 612 feet (186.5 m) long, and has a generating capacity of 28,800 kilowatts. The dam's concrete overfall spillway has a discharge capacity of 95000 cuft/s, 1560 cubic feet (44.2 m³) of which is via the dam's two 5 feet (1.5 m) by 7 feet (2.1 m) sluice gates located near the bottom of the dam. Ocoee Reservoir No. 3 has 360 acres (145.7 ha) of water surface and 24 miles (38.6 km) of shoreline. Major recreational releases are typically scheduled for weekends during the Summer months.
The powerhouse of Ocoee No. 3 was built 4.2 miles (6.8 km) downstream from the dam in order to obtain maximum utilization of the elevation loss along this stretch of the river. A high pressure conduit— most of which flows through a 12 feet (3.7 m) by 12 feet (3.7 m) tunnel carved into the mountainside— carries the water from the reservoir at a relatively steady elevation. The water emerges from the tunnel at a point 2.5 miles (4 km) from the reservoir intake and drops 180 feet (54.9 m) through a steel penstock
to the powerhouse's lone turbine.
The rapid-flowing Ocoee River's hydroelectric potential has been exploited by private interests, namely the Eastern Tennessee Power Company and its successor, the Tennessee Electric Power Company (TEPCO), since the completion of Ocoee Dam No. 1
in late 1911. While only a 47 miles (75.6 km) stretch of river remained between Ocoee Dam No. 2 (completed in 1913) and Blue Ridge Dam (completed in 1931), this stretch's average elevation loss of 46 feet (14 m) per mile made a third dam possible. The U.S. Army Corps of Engineers had surveyed the Ocoee No. 3 dam site in the late 1920s, and TEPCO had already purchased the necessary land and water rights for the dam by the 1930s.
The TVA Act of 1933 created the Tennessee Valley Authority and gave the Authority oversight of the entire Tennessee River
watershed, which includes the Ocoee. In 1939, a U.S. Supreme Court
ruling forced TEPCO to sell TVA its assets, which included the tract for Ocoee No. 3. While TVA identified the Ocoee No. 3 site as part of its Hiwassee Valley surveys in 1934, the idea for the dam received little attention until the outbreak of World War II in Europe sparked a need for increased aluminum production at the ALCOA plant in Alcoa, Tennessee
, which required large amounts of electricity. The Ocoee No. 3 project, along with several other dam projects in the Hiwassee watershed, was authorized on July 16, 1941. Construction began the following day.
Most of the land necessary for the construction of Ocoee Dam No. 3 and its reservoir had been obtained from TEPCO, and thus no residential or cemetery relocations were necessary. Work progressed at a steady pace, and the dam was completed on August 15, 1942. The diversion tunnel was completed in November of the same year, but budget delays prevented the dam's generator from becoming operational until April 30, 1943.
, which is two miles (3 km) downstream from Ocoee Dam No. 3.
TVA stated that the release was part of routine maintenance in anticipation of rain showers. The material was released via the dam's sluice gates, which are located at the bottom of the dam and are typically used for low-level and recreational releases. On January 12, 2009, in response to the incident, the Tennessee Department of Environment and Conservation
issued a notice of violation that ordered TVA to get state approval before using the dam's sluice gates, restore the affected areas, and submit a management plan for sluicing operations at the dam.
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 one of four dams on the Toccoa/Ocoee River 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...
, which built the dam in the early 1940s to meet emergency demands for electricity during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The dam impounds the 360 acres (145.7 ha) Ocoee No. 3 Reservoir, which stretches 11 miles (17.7 km) upriver to the Tennessee-Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
state line. Ocoee No. 3's powerhouse is actually located several miles downstream from the dam, and is fed by a 2.5 miles (4 km) conduit that carries water to it from the reservoir.
Location
Ocoee Dam No. 3 is located 29 miles (46.7 km) above the mouth of the Ocoee River, where the river slices a deep gap between Little Frog Mountain to the north and Big Frog MountainBig Frog Mountain
Big Frog Mountain is a mountain located in southeastern Tennessee in the Big Frog Wilderness, within the Cherokee National Forest. At tall, there is no higher point west of Big Frog Mountain until the Big Bend in Texas or the Black Hills of South Dakota...
to the south. Both of these mountains are protected by federal wilderness areas which are adjacent to TVA's Ocoee No. 3 reservation boundary. Ocoee Dam No. 2
Ocoee Dam No. 2
Ocoee Dam Number 2 is a hydroelectric dam on the Ocoee River in Polk County in the U.S. state of Tennessee. The dam impounds the Ocoee No. 2 Reservoir and is one of four dams on the Toccoa/Ocoee River owned and operated by the Tennessee Valley Authority. Ocoee Dam No...
is just 5 miles (8 km) downstream, and Blue Ridge Dam
Blue Ridge Dam
Blue Ridge Dam is a hydroelectric dam on the Toccoa River in Fannin County, in the U.S. state of Georgia. It is the uppermost of four dams on the Toccoa/Ocoee River owned and operated by the Tennessee Valley Authority...
is 23 miles (37 km) upstream. The Toccoa River, which flows down from its source in the Blue Ridge Mountains
Blue Ridge Mountains
The Blue Ridge Mountains are a physiographic province of the larger Appalachian Mountains range. This province consists of northern and southern physiographic regions, which divide near the Roanoke River gap. The mountain range is located in the eastern United States, starting at its southern-most...
of northern Georgia, enters Tennessee (where it becomes the Ocoee River) approximately 11 miles (17.7 km) upstream from Ocoee Dam No. 3, near the Copperhill
Copperhill, Tennessee
Copperhill is a city in Polk County, Tennessee, United States. The population was 511 at the 2000 census. It is included in the Cleveland, Tennessee Metropolitan Statistical Area.-Geography:...
area. The Ocoee Scenic Byway— which is part of U.S. Route 64
U.S. Route 64
U.S. Route 64 is an east–west United States highway that runs for 2,326 miles from eastern North Carolina to just southwest of the Four Corners in northeast Arizona. The western terminus is at U.S. Route 160 in Teec Nos Pos, Arizona. The highway's eastern terminus is at NC 12 and U.S. Route...
— passes just north of the dam.
Capacity
The powerhouse of Ocoee No. 3 was built 4.2 miles (6.8 km) downstream from the dam in order to obtain maximum utilization of the elevation loss along this stretch of the river. A high pressure conduit— most of which flows through a 12 feet (3.7 m) by 12 feet (3.7 m) tunnel carved into the mountainside— carries the water from the reservoir at a relatively steady elevation. The water emerges from the tunnel at a point 2.5 miles (4 km) from the reservoir intake and drops 180 feet (54.9 m) through a steel 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....
to the powerhouse's lone turbine.
Background and construction
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,...
in late 1911. While only a 47 miles (75.6 km) stretch of river remained between Ocoee Dam No. 2 (completed in 1913) and Blue Ridge Dam (completed in 1931), this stretch's average elevation loss of 46 feet (14 m) per mile made a third dam possible. The U.S. Army Corps of Engineers had surveyed the Ocoee No. 3 dam site in the late 1920s, and TEPCO had already purchased the necessary land and water rights for the dam by the 1930s.
The TVA Act of 1933 created the Tennessee Valley Authority and gave the Authority oversight of the entire 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, which includes the Ocoee. In 1939, a 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...
ruling forced TEPCO to sell TVA its assets, which included the tract for Ocoee No. 3. While TVA identified the Ocoee No. 3 site as part of its Hiwassee Valley surveys in 1934, the idea for the dam received little attention until the outbreak of World War II in Europe sparked a need for increased aluminum production at the ALCOA plant in Alcoa, Tennessee
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....
, which required large amounts of electricity. The Ocoee No. 3 project, along with several other dam projects in the Hiwassee watershed, was authorized on July 16, 1941. Construction began the following day.
Most of the land necessary for the construction of Ocoee Dam No. 3 and its reservoir had been obtained from TEPCO, and thus no residential or cemetery relocations were necessary. Work progressed at a steady pace, and the dam was completed on August 15, 1942. The diversion tunnel was completed in November of the same year, but budget delays prevented the dam's generator from becoming operational until April 30, 1943.
January 2009 sludge release
On January 4, 2009, TVA released a substantial amount of contaminated sludge-like material from the Ocoee No. 3 Reservoir into the Upper Ocoee immediately downstream, killing an undetermined number of fish and covering the river with a 3.5 feet (1.1 m) layer of "foul-smelling" sludge as far downstream as the Ocoee No. 2 Reservoir. The sludge was filled with contaminants— including copper, iron, and zinc— left over from the mining operations that once denuded the Ducktown Basin, which is adjacent to the Ocoee No. 3 reservoir. The release polluted the Ocoee Whitewater CenterOcoee Whitewater Center
The Ocoee Whitewater Center, near Ducktown, Tennessee, United States, was the canoe slalom venue for the 1996 Summer Olympics in Atlanta. The Olympic race course was built in the dry riverbed of the Upper Ocoee river. The Upper Ocoee is the section between Ocoee Dam #3 and its downstream...
, which is two miles (3 km) downstream from Ocoee Dam No. 3.
TVA stated that the release was part of routine maintenance in anticipation of rain showers. The material was released via the dam's sluice gates, which are located at the bottom of the dam and are typically used for low-level and recreational releases. On January 12, 2009, in response to the incident, the Tennessee Department of Environment and Conservation
Tennessee Department of Environment and Conservation
The Tennessee Department of Environment and Conservation is a Cabinet-level agency within the government of the U.S. state of Tennessee, headed by the Tennessee Commissioner of Environment and Conservation....
issued a notice of violation that ordered TVA to get state approval before using the dam's sluice gates, restore the affected areas, and submit a management plan for sluicing operations at the dam.
External links
- Ocoee Reservoir No. 3 — official TVA site
- Ocoee Dam No. 3 Recreational Release Schedule