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29-579: The lake stretches 75 miles (121 km) from Guntersville Dam to Nickajack Dam . It is Alabama's largest lake at 69,100 acres (279.6 km) . It is separated by the Guntersville Dam from Wheeler Lake , which is 68,300 acres (276.4 km) and the second largest lake. Both lakes are part of the Tennessee River. The lake was created by Guntersville Dam along the Tennessee River . Both the lake and

58-546: A light bulb with a power rating of 100 W is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360  kJ . This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours. Power stations are rated using units of power, typically megawatts or gigawatts (for example, the Three Gorges Dam in China is rated at approximately 22 gigawatts). This reflects

87-414: A series of foundation improvements that by 1943 had succeeded in halting the leaks. In 1960, however, the leaks had returned, spilling at an alarming 2,000 cubic feet per second (57 m /s). Around the same time, TVA began expanding locks on its dams to at least 600 feet (180 m) to accommodate the increase in traffic the river had experienced since World War II , and it was determined that expanding

116-535: A turbine, which generates 648 MW e (i.e. electricity). Other SI prefixes are sometimes used, for example gigawatt electrical (GW e ). The International Bureau of Weights and Measures , which maintains the SI-standard, states that further information about a quantity should not be attached to the unit symbol but instead to the quantity symbol (e.g., P th = 270 W rather than P = 270 W th ) and so these unit symbols are non-SI. In compliance with SI,

145-486: A unit of time, namely 1 J/s. In this new definition, 1 absolute watt = 1.00019 international watts. Texts written before 1948 are likely to be using the international watt, which implies caution when comparing numerical values from this period with the post-1948 watt. In 1960, the 11th General Conference on Weights and Measures adopted the absolute watt into the International System of Units (SI) as

174-400: Is 104 megawatts . Nickajack is serviced by a 600-by-110-foot (183 by 34 m) auxiliary lock that can lift or lower as many as nine large barges at a time 41 feet (12 m) between Guntersville Lake and Nickajack Lake. The dam's original design allowed for an 800-by-110-foot (244 by 34 m) main lock beside the auxiliary, but it was never completed. This lock, as well as every lock on

203-530: Is a stub . You can help Misplaced Pages by expanding it . Nickajack Dam Nickajack Dam is a hydroelectric dam in Marion County in the U.S. state of Tennessee . It is one of nine dams on the Tennessee River owned and operated by the Tennessee Valley Authority , which built the dam in the mid-1960s to replace the outdated Hales Bar Dam 6 miles (9.7 km) upstream. The dam impounds

232-700: Is named after the Scottish inventor James Watt . The unit name was proposed by C. William Siemens in August 1882 in his President's Address to the Fifty-Second Congress of the British Association for the Advancement of Science . Noting that units in the practical system of units were named after leading physicists, Siemens proposed that watt might be an appropriate name for a unit of power. Siemens defined

261-594: Is repeatedly noted as a top spot for bass fishing and one of the top lake towns to live in America. In the 1950s, German scientists brought to the United States under Operation Paperclip who lived in Huntsville, Alabama purchased houses by the lake. This Jackson County , Alabama state location article is a stub . You can help Misplaced Pages by expanding it . This Marshall County , Alabama state location article

290-523: Is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit). 1   W = 1   V ⋅ A . {\displaystyle \mathrm {1~W=1~V{\cdot }A} .} Two additional unit conversions for watt can be found using

319-811: The Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution . When an object's velocity is held constant at one meter per second against a constant opposing force of one newton , the rate at which work is done is one watt. 1   W = 1   J / s = 1   N ⋅ m / s = 1   k g ⋅ m 2 ⋅ s − 3 . {\displaystyle \mathrm {1~W=1~J{/}s=1~N{\cdot }m{/}s=1~kg{\cdot }m^{2}{\cdot }s^{-3}} .} In terms of electromagnetism , one watt

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348-413: The 10,370-acre (4,200 ha) Nickajack Lake and feeds into Guntersville Lake . Nickajack Dam is named for a Cherokee village once located just upstream from the dam (the site is now submerged). The village was the namesake for Nickajack Cave , which was partially flooded by the reservoir. Nickajack Dam is located 424 miles (682 km) above the mouth of the Tennessee River, near the point where

377-563: The Hales Bar Reservoir 6 miles (9.7 km) downstream to Nickajack— required the purchase of 8,300 acres (3,400 ha), 500 acres (200 ha) of which had to be cleared. 82 families and 8 miles (13 km) of roads had to be relocated. Two generators and several switchyard parts were moved from Hales Bar Dam to the new dam. Construction was completed on December 14, 1967, at a cost of $ 73 million (equivalent to $ 509 million in 2023 ). Operations at Hales Bar Dam were halted

406-589: The Hales Bar lock would be "prohibitively" expensive. Rather than spend the necessary expenses to upgrade Hales Bar, a decision was made in 1963 to build a new dam altogether on a more solid bedrock a few miles downstream. The Nickajack Dam project was authorized January 9, 1964, and construction began April 1, 1964. Funding set aside for repair work on Hales Bar was transferred to the Nickajack project. The reservoir's construction— which basically involved extending

435-612: The Tennessee River, is operated and maintained by the U.S. Army Corps of Engineers. Before the completion of Hales Bar Dam in 1913, the Tennessee River Gorge was one of the major impediments— along with Muscle Shoals and the Elk River shoals— to year-round navigation on the Tennessee River. Along with unpredictable water levels, the gorge was filled with numerous water hazards, some of which had been given nicknames such as "The Suck", "The Skillet", and "The Pan." In

464-467: The above equation and Ohm's law . 1   W = 1   V 2 / Ω = 1   A 2 ⋅ Ω , {\displaystyle \mathrm {1~W=1~V^{2}/\Omega =1~A^{2}{\cdot }\Omega } ,} where ohm ( Ω {\displaystyle \Omega } ) is the SI derived unit of electrical resistance . The watt

493-624: The company began building Hales Bar Dam in October of that year. Hales Bar's weak limestone foundation— which hadn't been considered in the selection of the dam site— presented numerous obstacles from the outset, but the dam was finally completed in 1913. In 1939, after a contentious court battle, TEPCO was forced to sell its assets— including Hales Bar Dam— to the Tennessee Valley Authority. The dam had been leaking since its construction, and TVA immediately initiated

522-599: The dam received their names from the town of Guntersville, which received its name from an early settler of the area, John Gunter . As far back as 1824, the Tennessee River was a nationwide inland waterway problem. With narrow canals, increased traffic, and larger freight carriers, in addition to flooding problems and sparse electricity, it was clear that a successful river development program should embrace power, navigation and flood control. The Tennessee Valley Act called for development of 640 miles of Tennessee River from Paducah, Kentucky to Knoxville, Tennessee. Since many of

551-588: The earliest settlers built their homes along the river, many Guntersville area families and farms were displaced. Alabama's largest archeological project excavated dozens of Indian sites before the area was flooded in January 1939. As a result of the Tennessee Valley Act and the creation of the lake, Guntersville has seen improved agriculture, energy, industry and recreation. Known for its hiking, camping, fishing, boating activities and scenery, Alabama's Lake City

580-529: The early 1900s, the U.S. Army Corps of Engineers realized that a dam near the southwestern end of the gorge would flood the water hazards and eliminate the gorge's rapid downstream current. Chattanooga engineer Josephus Conn Guild offered to raise funds to build this dam in exchange for rights to the dam's electrical output. After receiving authorization from Congress in 1904, he organized the Chattanooga and Tennessee River Power Company (later TEPCO) in 1905, and

609-515: The energy company Ørsted A/S uses the unit megawatt for produced electrical power and the equivalent unit megajoule per second for delivered heating power in a combined heat and power station such as Avedøre Power Station . When describing alternating current (AC) electricity, another distinction is made between the watt and the volt-ampere . While these units are equivalent for simple resistive circuits , they differ when loads exhibit electrical reactance . Radio stations usually report

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638-512: The following day, and by September 1968, Hales Bar Dam had been dismantled and its reservoir merged with Nickajack Lake. Megawatt The watt (symbol: W ) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m ⋅s . It is used to quantify the rate of energy transfer . The watt is named in honor of James Watt (1736–1819), an 18th-century Scottish inventor , mechanical engineer , and chemist who improved

667-460: The maximum power output it can achieve at any point in time. A power station's annual energy output, however, would be recorded using units of energy (not power), typically gigawatt hours. Major energy production or consumption is often expressed as terawatt hours for a given period; often a calendar year or financial year. One terawatt hour of energy is equal to a sustained power delivery of one terawatt for one hour, or approximately 114 megawatts for

696-488: The power of their transmitters in units of watts, referring to the effective radiated power . This refers to the power that a half-wave dipole antenna would need to radiate to match the intensity of the transmitter's main lobe . The terms power and energy are closely related but distinct physical quantities. Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time . For example, when

725-456: The states of Tennessee, Georgia , and Alabama meet. This stretch of the river marks a region where the river begins to exit the once treacherous Tennessee River Gorge en route to the flatlands around Guntersville, Alabama . The Sequatchie River empties into the dam's tailwaters, and the city of South Pittsburg is just over 5 miles (8.0 km) downstream from the dam. Nickajack Lake stretches northeast for over 46 miles (74 km), all

754-559: The unit of power. In the electric power industry , megawatt electrical ( MWe or MW e ) refers by convention to the electric power produced by a generator, while megawatt thermal or thermal megawatt (MWt, MW t , or MWth, MW th ) refers to thermal power produced by the plant. For example, the Embalse nuclear power plant in Argentina uses a fission reactor to generate 2,109 MW t (i.e. heat), which creates steam to drive

783-556: The unit within the existing system of practical units as "the power conveyed by a current of an Ampère through the difference of potential of a Volt". In October 1908, at the International Conference on Electric Units and Standards in London, so-called international definitions were established for practical electrical units. Siemens' definition was adopted as the international watt. (Also used: 1 A × 1 Ω.) The watt

812-520: The way to the base of Chickamauga Dam in Chattanooga . Tennessee State Highway 156 passes just south of Nickajack Dam, and Interstate 24 passes a few miles to the north. Nickajack Dam is 81 feet (25 m) high and 3,767 feet (1,148 m) long. Its reservoir has 179 miles (288 km) of shoreline and 10,370 acres (4,200 ha) of water surface. The dam's 10 spillway bays have a combined discharge of 360,000 cubic feet per second (10,000 m /s). The electrical generating capacity of Nickajack

841-420: Was defined as equal to 10 units of power in the practical system of units. The "international units" were dominant from 1909 until 1948. After the 9th General Conference on Weights and Measures in 1948, the international watt was redefined from practical units to absolute units (i.e., using only length, mass, and time). Concretely, this meant that 1 watt was defined as the quantity of energy transferred in

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