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85-663: Lake Hartwell is a man-made reservoir bordering Georgia and South Carolina and encompassing parts of the Savannah , Tugaloo , and Seneca rivers. Lake Hartwell is one of the Southeastern United States' largest recreation lakes. The lake was created by the construction of the Hartwell Dam , completed in 1962 and located on the Savannah River seven miles (11 km) below the point at which

170-415: A base there in 1567 called Fort San Juan . Expedition documentation and archaeological evidence of the fort and Native American culture both exist. The soldiers were at the fort about 18 months (1567–1568) before the natives killed them and destroyed the fort. (They killed soldiers stationed at five other forts as well; only one man of 120 survived.) Sixteenth-century Spanish artifacts have been recovered from

255-537: A block for migrating fish, trapping them in one area, producing food and a habitat for various water-birds. They can also flood various ecosystems on land and may cause extinctions. Creating reservoirs can alter the natural biogeochemical cycle of mercury . After a reservoir's initial formation, there is a large increase in the production of toxic methylmercury (MeHg) via microbial methylation in flooded soils and peat. MeHg levels have also been found to increase in zooplankton and in fish. Dams can severely reduce

340-815: A chain up the valley. Coastal reservoirs are fresh water storage reservoirs located on the sea coast near a river mouth to store the flood water of a river. As the land-based reservoir construction is fraught with substantial land submergence, coastal reservoirs are preferred economically and technically since they do not use scarce land area. Many coastal reservoirs were constructed in Asia and Europe. Saemanguem in South Korea, Marina Barrage in Singapore, Qingcaosha in China, and Plover Cove in Hong Kong are

425-658: A conventional oil-fired thermal generation plant. For instance, In 1990, the impoundment behind the Balbina Dam in Brazil (inaugurated in 1987) had over 20 times the impact on global warming than would generating the same power from fossil fuels, due to the large area flooded per unit of electricity generated. Another study published in the Global Biogeochemical Cycles also found that newly flooded reservoirs released more carbon dioxide and methane than

510-533: A drop of water seep into the ocean without benefiting mankind." He created the reservoir named Parakrama Samudra ("sea of King Parakrama"). Vast artificial reservoirs were also built by various ancient kingdoms in Bengal, Assam, and Cambodia. Many dammed river reservoirs and most bank-side reservoirs are used to provide the raw water feed to a water treatment plant which delivers drinking water through water mains. The reservoir does not merely hold water until it

595-525: A few such coastal reservoirs. Where water is pumped or siphoned from a river of variable quality or size, bank-side reservoirs may be built to store the water. Such reservoirs are usually formed partly by excavation and partly by building a complete encircling bund or embankment , which may exceed 6 km (4 miles) in circumference. Both the floor of the reservoir and the bund must have an impermeable lining or core: initially these were often made of puddled clay , but this has generally been superseded by

680-455: A high-level reservoir is filled with water using high-performance electric pumps at times when electricity demand is low, and then uses this stored water to generate electricity by releasing the stored water into a low-level reservoir when electricity demand is high. Such systems are called pump-storage schemes. Reservoirs can be used in a number of ways to control how water flows through downstream waterways: Reservoirs can be used to balance

765-570: A loss in both quantity and quality of water necessary for maintaining ecological balance and pose a risk of increasing severity and duration of droughts due to climate change. In summary, they consider it a misadaptation to climate change. Proponents of reservoirs or substitution reserves, on the other hand, see them as a solution for sustainable agriculture while waiting for a truly durable agricultural model. Without such reserves, they fear that unsustainable imported irrigation will be inevitable. They believe that these reservoirs should be accompanied by

850-419: A narrow valley or canyon may cover relatively little vegetation, while one situated on a plain may flood a great deal of vegetation. The site may be cleared of vegetation first or simply flooded. Tropical flooding can produce far more greenhouse gases than in temperate regions. The following table indicates reservoir emissions in milligrams per square meter per day for different bodies of water. Depending upon

935-482: A regional ceramic style in the southeast involving surface decorations applied with a carved wooden paddle. By the late 1960s, archaeological investigations had shown the similarity of the culture that produced the pottery and the midwestern Mississippian pattern defined in 1937 by the Midwestern Taxonomic System. In 1967, James B. Griffin coined South Appalachian Mississippian to describe

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1020-611: A reservoir is called the "conservation pool". In the United Kingdom, "top water level" describes the reservoir full state, while "fully drawn down" describes the minimum retained volume. There is a wide variety of software for modelling reservoirs, from the specialist Dam Safety Program Management Tools (DSPMT) to the relatively simple WAFLEX , to integrated models like the Water Evaluation And Planning system (WEAP) that place reservoir operations in

1105-598: A result of the impounded water in the reservoir. For instance, plans would cause the flooding of their Memorial Stadium . After countless meetings, Clemson finally settled with the government, agreeing to two diversion dams to be built in the vicinity of Clemson College in order to rechannel the Seneca River around its property. Since its construction, Hartwell Reservoir has provided good fishing habitat for many species. Bream , catfish , smallmouth bass , walleye , and largemouth bass are naturally occurring species in

1190-657: A rich history of indigenous settlement, dating to before the Mississippian culture period, which began about 800 CE. Numerous villages and platform mounds were built by people of that culture, along the upper tributaries of the Savannah River, such as the Chauga, Tugaloo, and Seneca rivers. The Cherokee Indians settled throughout much of this Piedmont and mountainous area, declaring it their homeland. Initial relations with colonists were through trading, but after

1275-740: A river valley, with the potential to wash away towns and villages and cause considerable loss of life, such as the devastation following the failure of containment at Llyn Eigiau which killed 17 people. (see also List of dam failures ) A notable case of reservoirs being used as an instrument of war involved the British Royal Air Force Dambusters raid on Germany in World War II (codenamed " Operation Chastise " ), in which three German reservoir dams were selected to be breached in order to damage German infrastructure and manufacturing and power capabilities deriving from

1360-602: A team from the University of Georgia in this work, especially from 1957 to 1959. Lake Hartwell is named for the American Revolutionary War figure Nancy Hart . Nancy Hart lived in the Georgia frontier, and was known for her devotion to freedom. A county, city, lake, state park and highway among others, bear her name. 1989 was the first year the lake hit a level 3, dropping to its lowest level during

1445-582: A territorial project that unites all water stakeholders with the goal of preserving and enhancing natural environments. Two main types of reservoirs can be distinguished based on their mode of supply. Circa 3000 BC, the craters of extinct volcanoes in Arabia were used as reservoirs by farmers for their irrigation water. Dry climate and water scarcity in India led to early development of stepwells and other water resource management techniques, including

1530-585: A tool or ally in long-standing native feuds. In one example, de Soto negotiated a truce between the Pacaha and the Casqui . De Soto's later encounters left about half of the Spaniards and perhaps many hundreds of Native Americans dead. The chronicles of de Soto are among the first documents written about Mississippian peoples and are an invaluable source of information on their cultural practices. The chronicles of

1615-457: A variety of functions. Villages with single platform mounds were more typical of the river valley settlements throughout the mountainous area of southwest North and South Carolina and southeastern Tennessee that were known as the historic Cherokee homelands. In Western North Carolina for example, some 50 such mound sites in the eleven westernmost counties have been identified since the late 20th century, following increased research in this area of

1700-476: Is a natural lake whose level was raised by a low dam and into which the River Dee flows or discharges depending upon flow conditions, as part of the River Dee regulation system . This mode of operation is a form of hydraulic capacitance in the river system. Many reservoirs often allow some recreational uses, such as fishing and boating . Special rules may apply for the safety of the public and to protect

1785-484: Is a water reservoir for agricultural use. They are filled using pumped groundwater , pumped river water or water runoff and are typically used during the local dry season. This type of infrastructure has sparked an opposition movement in France, with numerous disputes and, for some projects, protests, especially in the former Poitou-Charentes region where violent demonstrations took place in 2022 and 2023. In Spain, there

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1870-437: Is also used technically to refer to certain forms of liquid storage, such the "coolant reservoir" that captures overflow of coolant in an automobile's cooling system. Dammed reservoirs are artificial lakes created and controlled by a dam constructed across a valley and rely on the natural topography to provide most of the basin of the reservoir. These reservoirs can either be on-stream reservoirs , which are located on

1955-399: Is an enlarged lake behind a dam , usually built to store fresh water , often doubling for hydroelectric power generation . Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, excavating, or building any number of retaining walls or levees to enclose any area to store water. The term

2040-432: Is believed that the peoples of this area adopted Mississippian traits from their northwestern neighbors. Typical settlements were located on riverine floodplains and included villages with defensive palisades enclosing platform mounds and residential areas. Etowah and Ocmulgee in Georgia are both prominent examples of major South Appalachian Mississippian settlements. Both include multiple large earthwork mounds serving

2125-501: Is greater acceptance because all beneficiary users are involved in the implementation of the system. The specific debate about substitution reservoirs is part of a broader discussion related to reservoirs used for agricultural irrigation, regardless of their type, and a certain model of intensive agriculture. Opponents view these reservoirs as a monopolization of resources benefiting only a few, representing an outdated model of productive agriculture. They argue that these reservoirs lead to

2210-466: Is needed: it can also be the first part of the water treatment process. The time the water is held before it is released is known as the retention time . This is a design feature that allows particles and silts to settle out, as well as time for natural biological treatment using algae , bacteria and zooplankton that naturally live in the water. However natural limnological processes in temperate climate lakes produce temperature stratification in

2295-536: Is now used by the Aquarius Golf Club. Service reservoirs perform several functions, including ensuring sufficient head of water in the water distribution system and providing water capacity to even-out peak demand from consumers, enabling the treatment plant to run at optimum efficiency. Large service reservoirs can also be managed to reduce the cost of pumping by refilling the reservoir at times of day when energy costs are low. An irrigation reservoir

2380-419: Is stored in the reservoir. Any excess water can be spilled via a specifically designed spillway. Stored water may be piped by gravity for use as drinking water , to generate hydro-electricity or to maintain river flows to support downstream uses. Occasionally reservoirs can be managed to retain water during high rainfall events to prevent or reduce downstream flooding. Some reservoirs support several uses, and

2465-710: Is the chronological stage, while Mississippian culture refers to the cultural similarities that characterize this society. The term Middle Mississippian is also used to describe the core of the classic Mississippian culture area. This area covers the central Mississippi River Valley, the lower Ohio River Valley, and most of the Mid-South area, including western and central Kentucky, western Tennessee, and northern Alabama and Mississippi. Sites in this area often contain large ceremonial platform mounds, residential complexes and are often encircled by earthen ditches and ramparts or palisades . Middle Mississippian cultures, especially

2550-473: Is the portion of the reservoir that can be used for flood control, power production, navigation , and downstream releases. In addition, a reservoir's "flood control capacity" is the amount of water it can regulate during flooding. The "surcharge capacity" is the capacity of the reservoir above the spillway crest that cannot be regulated. In the United States, the water below the normal maximum level of

2635-400: Is usually divided into three or more chronological periods. Each period is an arbitrary historical distinction varying regionally. At a particular site, each period may be considered to begin earlier or later, depending on the speed of adoption or development of given Mississippian traits. The "Mississippian period" should not be confused with the "Mississippian culture". The Mississippian period

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2720-790: The Hasinai , Kadohadacho , and Natchitoches , which were all linked by their similar languages. The Plaquemine culture was an archaeological culture in the lower Mississippi River Valley in western Mississippi and eastern Louisiana . Good examples of this culture are the Medora site (the type site for the culture and period) in West Baton Rouge Parish, Louisiana , and the Anna , Emerald Mound , Winterville and Holly Bluff sites located in Mississippi. Plaquemine culture

2805-753: The Narváez expedition were written before the de Soto expedition; the Narváez expedition informed the Court of de Soto about the New World. After the destruction and flight of the de Soto expedition, the Mississippian peoples continued their way of life with little direct European influence. Indirectly, however, European introductions dramatically changed these native societies. Because the natives lacked immunity to infectious diseases unknowingly carried by

2890-695: The Revolutionary War , European-American settlers increasingly encroached on Cherokee territory. They have since named many streams, rivers and recreation areas after the historic Cherokee and Muscogee Creek, who were among the Five Civilized Tribes removed from the Southeast under President Andrew Jackson in the 1830s. Other historic figures who lived around this area were Andrew Pickens and John C. Calhoun , both statesmen from South Carolina. The botanist William Bartram traveled

2975-452: The Ruhr and Eder rivers. The economic and social impact was derived from the enormous volumes of previously stored water that swept down the valleys, wreaking destruction. This raid later became the basis for several films. All reservoirs will have a monetary cost/benefit assessment made before construction to see if the project is worth proceeding with. However, such analysis can often omit

3060-673: The 1800s, most of which are lined with brick. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909. When it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe. This reservoir now forms part of the southern extension of the Thames Water Ring Main . The top of the reservoir has been grassed over and

3145-561: The Cahokia polity located near East St. Louis, Illinois , were very influential on neighboring societies. High-status artifacts, including stone statuary and elite pottery associated with Cahokia, have been found far outside of the Middle Mississippian area. These items, especially the pottery, were also copied by local artists. The term South Appalachian Province was originally used by W. H. Holmes in 1903 to describe

3230-598: The Cherokee homeland. The Caddoan Mississippian area, a regional variant of the Mississippian culture, covered a large territory, including what is now eastern Oklahoma , western Arkansas , northeastern Texas , and northwestern Louisiana . Archaeological evidence has led to a scholarly consensus that the cultural continuity is unbroken from prehistory to the present, and that the Caddo and related Caddo language speakers in prehistoric times and at first European contact are

3315-540: The Europeans, such as measles and smallpox , epidemics caused so many fatalities that they undermined the social order of many chiefdoms. Some groups adopted European horses and changed to nomadism . Political structures collapsed in many places. At Joara , near Morganton, North Carolina , Native Americans of the Mississippian culture interacted with Spanish colonizers of the Juan Pardo expedition, who built

3400-537: The Georgia side and 3,935 feet (1,199 m) long on the South Carolina side. The 12,400 foot (3,800 m) long dam was to be topped with a roadway 24 feet (7.3 m) wide. The main dam was to consist of two non-overflow concrete sections on the right and left banks 887 feet (270 m) and 940 feet (290 m) long, respectively; a gravity-type concrete spillway 588 feet (179 m) long equipped with 12 tainter gates 26 by 40 feet (7.9 by 12.2 m) in

3485-731: The Meroitic town of Butana . The Hafirs catch the water during rainy seasons in order to ensure water is available for several months during dry seasons to supply drinking water, irrigate fields and water cattle. The Great Reservoir near the Lion Temple in Musawwarat es-Sufra is a notable hafir in Kush. In Sri Lanka , large reservoirs were created by ancient Sinhalese kings in order to store water for irrigation. The famous Sri Lankan king Parākramabāhu I of Sri Lanka said "Do not let

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3570-801: The Seneca to the mouth of the Little River, South Carolina; 2 miles (3.2 km) up the Little River to the Newry site; and 7 miles (11 km) up the Keowee to the Old Pickens site. The reservoir would cover 56,500 acres (22,900 ha) and would involve the relocation of 3 sections of railroad totaling 2 miles (3.2 km), the raising of 2 railroad bridges, construction of 6 sections of new state high- ways, totaling 19.6 miles (31.5 km), and 9 sections of county roads totaling 12.7 miles (20.4 km);

3655-513: The Tugaloo and Seneca Rivers join to form the Savannah. Extending 49 miles (79 km) up the Tugaloo and 45 miles (72 km) up the Seneca at normal pool elevation, the lake comprises nearly 56,000 acres (230 km) of water with a shoreline of 962 miles (1,548 km). The entire Hartwell "Project" contains 76,450 acres (309 km) of land and water. I-85 bisects Hartwell Lake and makes

3740-488: The US. The capacity, volume, or storage of a reservoir is usually divided into distinguishable areas. Dead or inactive storage refers to water in a reservoir that cannot be drained by gravity through a dam's outlet works , spillway, or power plant intake and can only be pumped out. Dead storage allows sediments to settle, which improves water quality and also creates an area for fish during low levels. Active or live storage

3825-704: The amount of water reaching countries downstream of them, causing water stress between the countries, e.g. the Sudan and Egypt , which damages farming businesses in the downstream countries, and reduces drinking water. Mississippian culture The Mississippian way of life began to develop in the Mississippi River Valley (for which it is named). Cultures in the tributary Tennessee River Valley may have also begun to develop Mississippian characteristics at this point. Almost all dated Mississippian sites predate 1539–1540 (when Hernando de Soto explored

3910-606: The area easily accessible to visitors. The Flood Control Act of May 17, 1950 authorized the Hartwell Dam and Reservoir as the second unit in the comprehensive development of the Savannah River Basin. The estimated cost was $ 68.4 million based on 1948 price levels and preliminary designs. The original project provided for a gravity-type concrete dam 2,415 feet (736 m) long with earth embankments at either end, which would be 6,050 feet (1,840 m) long on

3995-535: The area flooded versus power produced, a reservoir built for hydro- electricity generation can either reduce or increase the net production of greenhouse gases when compared to other sources of power. A study for the National Institute for Research in the Amazon found that hydroelectric reservoirs release a large pulse of carbon dioxide from decay of trees left standing in the reservoirs, especially during

4080-570: The area recording vegetation types and plant species. In August 1956, Eliza Brock and her daughter refused to allow workmen to come on their property to begin clearing for the reservoir area. The government had gained ownership of 103 acres (42 ha) of land in June 1956, but apparently Brock never received the offer for her land. After an October 1956 federal ruling, Brock settled on accepting $ 6,850 for her property. In late 1956, Clemson College objected to damage that would be done to its property as

4165-784: The area), with notable exceptions being Natchez communities. These maintained Mississippian cultural practices into the 18th century. A number of cultural traits are recognized as being characteristic of the Mississippians. Although not all Mississippian peoples practiced all of the following activities, they were distinct from their ancestors in the adoption of some or all of these traits. The Mississippians had no writing system or stone architecture. They worked naturally occurring metal deposits, such as hammering and annealing copper for ritual objects such as Mississippian copper plates and other decorations, but did not smelt iron or practice bronze metallurgy . The Mississippian stage

4250-428: The base of the dam or some distance away. In a flat river valley a reservoir needs to be deep enough to create a head of water at the turbines; and if there are periods of drought the reservoir needs to hold enough water to average out the river's flow throughout the year(s). Run-of-the-river hydro in a steep valley with constant flow needs no reservoir. Some reservoirs generating hydroelectricity use pumped recharge:

4335-556: The building of a reservoir at Girnar in 3000 BC. Artificial lakes dating to the 5th century BC have been found in ancient Greece. The artificial Bhojsagar lake in present-day Madhya Pradesh state of India, constructed in the 11th century, covered 650 square kilometres (250 sq mi). The Kingdom of Kush invented the Hafir , a type of reservoir, during the Meroitic period . 800 ancient and modern hafirs have been registered in

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4420-435: The channel; and a powerhouse on the South Carolina side of the river. Full power pool was designed to be 660 feet (200 m) above mean sea level . At this elevation, the reservoir would extend 7.1 miles (11.4 km) up the Savannah River to the confluence of the Tugaloo and Seneca Rivers; 41 miles (66 km) up the Tugaloo to within approximately 2 miles (3.2 km) of the existing Yonah Dam ; 27 miles (43 km) up

4505-547: The construction of 9 new bridges and the raising of 4 existing bridges, and the relocation of 2 power transmission lines. Construction of the Hartwell project took place from 1955 and was completed in 1963. Construction of the dam started in 1955 and was finished in 1959. Salvage archeological excavations were conducted at several sites in an effort to recover artifacts and information from prehistoric and historic sites that would be inundated by Lake Hartwell. Joseph Caldwell led

4590-442: The context of system-wide demands and supplies. In many countries large reservoirs are closely regulated to try to prevent or minimize failures of containment. While much of the effort is directed at the dam and its associated structures as the weakest part of the overall structure, the aim of such controls is to prevent an uncontrolled release of water from the reservoir. Reservoir failures can generate huge increases in flow down

4675-561: The dam located at the narrowest practical point to provide strength and the lowest cost of construction. In many reservoir construction projects, people have to be moved and re-housed, historical artifacts moved or rare environments relocated. Examples include the temples of Abu Simbel (which were moved before the construction of the Aswan Dam to create Lake Nasser from the Nile in Egypt ),

4760-460: The developed world Naturally occurring lakes receive organic sediments which decay in an anaerobic environment releasing methane and carbon dioxide . The methane released is approximately 8 times more potent as a greenhouse gas than carbon dioxide. As a human-made reservoir fills, existing plants are submerged and during the years it takes for this matter to decay, will give off considerably more greenhouse gases than lakes do. A reservoir in

4845-557: The direct ancestors of the modern Caddo Nation of Oklahoma . The climate in this area was drier than areas in the eastern woodlands, hindering maize production, and the lower population on the plains to the west may have meant fewer neighboring competing chiefdoms to contend with. Major sites such as Spiro and the Battle Mound Site are in the Arkansas River and Red River Valleys, the largest and most fertile of

4930-507: The downstream river to maintain river quality, support fisheries, to maintain downstream industrial and recreational uses or for a range of other purposes. Such releases are known as compensation water . The units used for measuring reservoir areas and volumes vary from country to country. In most of the world, reservoir areas are expressed in square kilometers; in the United States, acres are commonly used. For volume, either cubic meters or cubic kilometers are widely used, with acre-feet used in

5015-515: The drought that year. 2008 was the second time the lake hit a level 3. In December 2008, due to severe drought in the southeastern United States, the lake dropped to more than 22 feet (6.7 m) below its normal water level. This revealed old highways that were typically underwater, exposed islands that are usually topped with buoys to warn boaters, and left some boat shells sitting on dry land. The Lake reached its lowest level, 637.49 feet (194.31 m), on December 9, 2008. The highest lake elevation

5100-440: The environmental impacts of dams and the reservoirs that they contain. Some impacts, such as the greenhouse gas production associated with concrete manufacture, are relatively easy to estimate. Other impacts on the natural environment and social and cultural effects can be more difficult to assess and to weigh in the balance but identification and quantification of these issues is now commonly required in major construction projects in

5185-420: The evolving understanding of the peoples of the Southeast. South Appalachian Mississippian area sites are distributed across a contiguous area including Alabama, Georgia, northern Florida, South Carolina, central and western North Carolina, and Tennessee. Chronologically this area became influenced by Mississippian culture later than the Middle Mississippian area (about 1000 as compared to 800) to its northwest. It

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5270-499: The first decade after flooding. This elevates the global warming impact of the dams to levels much higher than would occur by generating the same power from fossil fuels . According to the World Commission on Dams report (Dams And Development), when the reservoir is relatively large and no prior clearing of forest in the flooded area was undertaken, greenhouse gas emissions from the reservoir could be higher than those of

5355-413: The flow in highly managed systems, taking in water during high flows and releasing it again during low flows. In order for this to work without pumping requires careful control of water levels using spillways . When a major storm approaches, the dam operators calculate the volume of water that the storm will add to the reservoir. If forecast storm water will overfill the reservoir, water is slowly let out of

5440-580: The hydroelectric reservoirs there do emit greenhouse gases, it is on a much smaller scale than thermal power plants of similar capacity. Hydropower typically emits 35 to 70 times less greenhouse gases per TWh of electricity than thermal power plants. A decrease in air pollution occurs when a dam is used in place of thermal power generation, since electricity produced from hydroelectric generation does not give rise to any flue gas emissions from fossil fuel combustion (including sulfur dioxide , nitric oxide and carbon monoxide from coal ). Dams can produce

5525-486: The lake, with quality fishing available for those species. The most popular fishing on Lake Hartwell, however, has been of striped bass. Striped Bass , also known as rock fish and normally a saltwater fish, were discovered able to survive in freshwater after the construction of a dam on the Santee-Cooper system in lower South Carolina trapped many striped bass in fresh water. Striped bass were eventually introduced to

5610-432: The landscape is relatively flat. Other service reservoirs can be storage pools, water tanks or sometimes entirely underground cisterns , especially in more hilly or mountainous country. Modern reserviors will often use geomembrane liners on their base to limit seepage and/or as floating covers to limit evaporation, particularly in arid climates. In the United Kingdom, Thames Water has many underground reservoirs built in

5695-750: The majority of the American Indian nations living in this region when European trade began. The historic and modern day American Indian nations believed to have descended from the overarching Mississippian culture include: the Alabama , Apalachee , Arikara , Caddo , Chickasaw , Catawba , Choctaw , Muscogee Creek , Guale , Hitchiti , Ho-Chunk , Houma , Iowa , Kansa , Koroas , Missouria , Mobilian , Natchez , Omaha , Osage (possibly), Otoe , Pawnee , Ponca , Quapaw (possibly), Seminole (broad origins), Taensas , Tunicas , Yamasee , Yazoos , and Yuchi . Scholars have studied

5780-512: The many Caddoan languages . These languages once had a broad geographic distribution, but many are now extinct. The modern languages in the Caddoan family include Caddo and Pawnee . Hernando de Soto led an expedition into the area in the early 1540s, he encountered several native groups now thought to have been Caddoan. Composed of many tribes, the Caddo were organized into three confederacies,

5865-470: The modern use of rolled clay. The water stored in such reservoirs may stay there for several months, during which time normal biological processes may substantially reduce many contaminants and reduce turbidity . The use of bank-side reservoirs also allows water abstraction to be stopped for some time, for instance when the river is unacceptably polluted or when flow conditions are very low due to drought . The London water supply system exhibits one example of

5950-609: The new top water level exceeds the watershed height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales . In such cases additional side dams are required to contain the reservoir. Where the topography is poorly suited to forming a single large reservoir, a number of smaller reservoirs may be constructed in a chain, as in the River Taff valley where the Llwyn-on , Cantref and Beacons Reservoirs form

6035-415: The operating rules may be complex. Most modern reservoirs have a specially designed draw-off tower that can discharge water from the reservoir at different levels, both to access water as the water level falls, and to allow water of a specific quality to be discharged into the downstream river as "compensation water": the operators of many upland or in-river reservoirs have obligations to release water into

6120-428: The original streambed of the downstream river and are filled by creeks , rivers or rainwater that runs off the surrounding forested catchments, or off-stream reservoirs , which receive diverted water from a nearby stream or aqueduct or pipeline water from other on-stream reservoirs. Dams are typically located at a narrow part of a downstream of a natural basin. The valley sides act as natural walls, with

6205-481: The pre-flooded landscape, noting that forest lands, wetlands, and preexisting water features all released differing amounts of carbon dioxide and methane both pre- and post-flooding. The Tucuruí Dam in Brazil (completed in 1984) had only 0.4 times the impact on global warming than would generating the same power from fossil fuels. A two-year study of carbon dioxide and methane releases in Canada concluded that while

6290-437: The quality of the water and the ecology of the surrounding area. Many reservoirs now support and encourage less formal and less structured recreation such as natural history , bird watching , landscape painting , walking and hiking , and often provide information boards and interpretation material to encourage responsible use. Water falling as rain upstream of the reservoir, together with any groundwater emerging as springs,

6375-509: The records of Hernando de Soto 's expedition of 1539–1543 to learn of his contacts with Mississippians, as he traveled through their villages of the Southeast. He visited many villages, in some cases staying for a month or longer. The list of sites and peoples visited by the Hernando de Soto Expedition chronicles those villages. Some encounters were violent, while others were relatively peaceful. In some cases, de Soto seems to have been used as

6460-464: The relocation of the village of Capel Celyn during the construction of Llyn Celyn , and the relocation of Borgo San Pietro of Petrella Salto during the construction of Lake Salto . Construction of a dammed reservoir will usually require the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are often constructed by enlarging existing lakes. Sometimes in such reservoirs,

6545-638: The reservoir prior to, and during, the storm. If done with sufficient lead time, the major storm will not fill the reservoir and areas downstream will not experience damaging flows. Accurate weather forecasts are essential so that dam operators can correctly plan drawdowns prior to a high rainfall event. Dam operators blamed a faulty weather forecast on the 2010–2011 Queensland floods . Examples of highly managed reservoirs are Burrendong Dam in Australia and Bala Lake ( Llyn Tegid ) in North Wales . Bala Lake

6630-477: The site, marking the first European colonization in the interior of what became the United States. By the time more documentary accounts were being written, the Mississippian way of life had changed irrevocably. Some groups maintained an oral tradition link to their mound-building past, such as the late 19th-century Cherokee . Other Native American groups, having migrated many hundreds of miles and lost their elders to diseases, did not know their ancestors had built

6715-589: The three lower Savannah River System lakes: Hartwell, Russel, and Thurmond. Fish heavier than 60 pounds (27 kg) have been caught on Lake Hartwell, with 20 pounds (9.1 kg) fish being common. The majority of striped bass caught on the lake will range from 5 to 12 pounds (2.3 to 5.4 kg). [REDACTED]  This article incorporates public domain material from History of Hartwell Dam & Lake . United States Army . Reservoir A reservoir ( / ˈ r ɛ z ər v w ɑːr / ; from French réservoir [ʁezɛʁvwaʁ] )

6800-499: The use of bank-side storage: here water is taken from the River Thames and River Lee into several large Thames-side reservoirs, such as Queen Mary Reservoir that can be seen along the approach to London Heathrow Airport . Service reservoirs store fully treated potable water close to the point of distribution. Many service reservoirs are constructed as water towers , often as elevated structures on concrete pillars where

6885-412: The water, which tends to partition some elements such as manganese and phosphorus into deep, cold anoxic water during the summer months. In the autumn and winter the lake becomes fully mixed again. During drought conditions, it is sometimes necessary to draw down the cold bottom water, and the elevated levels of manganese in particular can cause problems in water treatment plants. In 2005, about 25% of

6970-525: The waterways in the Caddoan region, where maize agriculture would have been the most productive. The sites generally lacked wooden palisade fortifications often found in the major Middle Mississippian towns. Living on the western edge of the Mississippian world, the Caddoans may have faced fewer military threats from their neighbors. Their societies may also have had a somewhat lower level of social stratification . The Caddoan people were speakers of one of

7055-476: The world's 33,105 large dams (over 15 metres in height) were used for hydroelectricity. The U.S. produces 3% of its electricity from 80,000 dams of all sizes. An initiative is underway to retrofit more dams as a good use of existing infrastructure to provide many smaller communities with a reliable source of energy. A reservoir generating hydroelectricity includes turbines connected to the retained water body by large-diameter pipes. These generating sets may be at

7140-420: Was 665.4 feet (202.8 m), reached on April 8, 1964. Overall the average lake elevation is 657.5 feet (200.4 m). As of the first of October 2010, the lake had returned to just over 654 feet (199 m). This rebound in lake level is due to releases from the lake being suspended for a month ending April 10, 2009, in an effort to return Lake Hartwell to normal elevations. The area around Lake Hartwell has

7225-557: Was contemporaneous with the Middle Mississippian culture at the Cahokia site near St. Louis , Missouri. It is considered ancestral to the Natchez and Taensa Peoples. Although the Mississippian culture was heavily disrupted before a complete understanding of the political landscape was written down, many Mississippian political bodies were documented and others have been discovered by research. Mississippian peoples were ancestral to

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