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Karun-3 dam, Iran.
Karun-3 dam, Iran.
Hydroelectric dam in cross section.
Hydroelectric dam in cross section.

A dam is a barrier that divides waters. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates, levees, and dikes are used to prevent water flow into specific land regions. The tallest dam in the world is the 300 meter high Nurek Dam in Tajikistan.[1] The words dam and damn have very different meanings, but they are sometimes confused in spelling, particularly by foreigners. ... Image File history File links Download high resolution version (640x639, 383 KB)Karun-3 Dam, Khuzestan. ... Image File history File links Download high resolution version (640x639, 383 KB)Karun-3 Dam, Khuzestan. ... The Karun-3 Dam The Karun-3 dam is a hydroelectric dam on the Karun river in the province of Khuzestan, Iran. ... Image File history File links Hydroelectric_dam. ... Image File history File links Hydroelectric_dam. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Tokyo floodgates to protect from typhoon surges. ... A levee, levée (from the feminine past participle of the French verb lever, to raise), floodbank or stopbank is a natural or artificial slope or wall, usually earthen and often parallels the course of a river. ... Afsluitdijk, a 32 km dike in the Netherlands. ... The Nurek (Norak) Dam is a large earthfill dam located at 38. ...

Contents

History

The word dam can be traced back to Middle English,[2] and before that, from Middle Dutch, as seen in the names of many old cities.[3] Middle English is the name given by historical linguistics to the diverse forms of the English language spoken between the Norman invasion of 1066 and the mid-to-late 15th century, when the Chancery Standard, a form of London-based English, began to become widespread, a process aided by the... Linguistically speaking, Middle Dutch is no more than a collective name for closely related languages or dialects which were spoken and written between about 1150 and 1500 in the present-day Dutch-speaking region. ...


The grandest and largest dams were constructed in Ceylon (Sri Lanka).[4] Dams in Yodha Wewa and Parakrama Samudra of Sri Lanka were the largest until the 20th Century . As per Needham, Abhaya Wewa is the oldest reservoir that was made by the use of a dam, which has been dated to 300 BC. ([5] Most of the first Dams were built in Mesopotamia up to 7,000 years ago. These were used to control the water level, for Mesopotamia's weather affected the Tigris and Euphrates rivers, and could be quite unpredictable. The earliest recorded dam is believed to have been on the Sadd Al-Kafara at Wadi Al-Garawi, which is located about 25 kilometers south of Cairo, and built around 2600 B.C.[6] It was destroyed by heavy rain shortly afterwards.[6] The Democratic Socialist Republic of Sri Lanka (ශ්රී ලංකා in Sinhala / இலங்கை in Tamil) (known as Ceylon before 1972) is a tropical island nation off the southeast coast of the Indian subcontinent. ... Mesopotamia was a cradle of civilization geographically located between the Tigris and Euphrates rivers, largely corresponding to modern-day Iraq. ... The Tigris is the eastern member of the pair of great rivers that define Mesopotamia, along with the Euphrates, which flows from the mountains of Anatolia through Iraq. ... For the song River Euphrates by the Pixies, see Surfer Rosa. ...


The oldest surviving and standing dam in the world is believed to be the Grand Anicut, also known as the Kallanai, an ancient dam built on the Kaveri River in the state of Tamil Nadu located in southern India. It was built by the Chola king Karikalan, and dates back to the 2nd Century AD.[7] Du Jiang Yan in China is the oldest surviving irrigation system included a dam that directed waterflow. It was finished in 251 B.C. The Kallanai (Tamil kall - stone, anai- bund), also known as the Grand Anicut, is is an ancient dam in Tamil Nadu state of southern India. ... The big time , also known as the Grand Anicut, is an ancient dam in Tamil Nadu state of southern India. ... This article is about a river. ... Tamil Nadu (தமிழ் நாடு, Land of the Tamils) is a state at the southern tip of India. ... The Cholas were the most famous of the three dynasties that ruled ancient Tamil Nadu. ... Karikalan was the first Chola king who was very famous for his valour and his justice. ... Du Jiang Yan (Simplified Chinese: ; Traditional Chinese: ; pinyin: ) is an irrigation infastucture built in 256 BC during the Warring States Period of China by the Kingdom of Qin. ...


The Kallanai is a massive dam of unhewn stone, over 300 meters long, 4.5 meters high and 20 meters (60 ft) wide,[7] across the main stream of the Kaveri. The purpose of the dam was to divert the waters of the Cauvery across the fertile Delta region for irrigation via canals. The dam is still in excellent repair, and served as a model for later engineers, including the Sir Arthur Cotton's 19th-century dam across the Kollidam, the major tributary of the Cauvery. The land area irrigated by the ancient irrigation network, of which the dam was the centerpiece, was 69,000 acres (280 square kilometers). By the early 20th Century the irrigated area had been increased to about 1,000,000 acres (4,000 square kilometers). The big time , also known as the Grand Anicut, is an ancient dam in Tamil Nadu state of southern India. ... This article is about the unit of measurement. ...


In ancient China, the Prime Minister of Chu (state), Sunshu Ao, is the first known hydraulic engineer of China. He served Duke Zhuang of Chu during the reign of King Ding of Zhou (606 BC-586 BC), ruler of the Eastern Zhou Dynasty. His large earthen dam flooded a valley in modern-day northern Anhui province that created an enormous irrigation reservoir (62 miles in circumference), a reservoir that is still present today.[8] China is the worlds oldest continuous major civilization, with written records dating back about 3,500 years and with 5,000 years being commonly used by Chinese as the age of their civilization. ... A prime minister is the most senior minister of cabinet in the executive branch of government in a parliamentary system. ... State of Chu (small seal script, 220 BC) Chu (楚) was a kingdom in what is now southern China during the Spring and Autumn period (722-481 BCE) and Warring States Period (481-212 BCE). ... Sunshu Ao (孫叔敖) was an ancient Chinese court minister serving the administration of Duke Zhuang of Chu during the reign of King Ding of Zhou (606 BC-586 BC), during the Eastern Zhou Dynasty. ... Hydraulic engineering is a sub-discipline of civil engineering concerned with the flow and conveyance of fluids, principally water. ... King Zhuāng of Chu (楚莊王) (died 591 BC) was leader in the state of Chu in the Spring and Autumn Period of Chinese history. ... King Ding of Zhou (ch. ... Alternative meaning: Zhou Dynasty (690 CE - 705 CE) The Zhou Dynasty (周朝; Wade-Giles: Chou Dynasty) (late 10th century BC to late 9th century BC - 256 BC) followed the Shang (Yin) Dynasty and preceded the Qin Dynasty in China. ... Anhui (Chinese: 安徽; Hanyu Pinyin: ; Wade-Giles: An-hui; Postal System Pinyin: Ngan-hui, Anhwei or An-hwei) is a province of the Peoples Republic of China. ... Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ...


In the Netherlands, a low-lying country, dams were often applied to block rivers in order to regulate the water level and to prevent the sea from entering the marsh lands. Such dams often marked the beginning of a town or city because it was easy to cross the river at such a place, and often gave rise to the respective place's names in Dutch. For instance the Dutch capital Amsterdam (old name Amstelredam) started with a dam through the river Amstel in the late 12th Century , and Rotterdam started with a dam through the river Rotte, a minor tributary of the Nieuwe Maas. The central square of Amsterdam, believed to be the original place of the 800 year old dam, still carries the name Dam Square or simply the Dam. Capital City is a 60-minute television show produced by Euston Films that ran for 13 episodes in 1989 on ITV. This drama focused on the lives of investment bankers in London living and working on the corporate trading floor for the fictional international bank Shane-Longman. ... For other uses, see Amsterdam (disambiguation). ... The Amstel is a river in the Netherlands which runs through the city of Amsterdam. ... Nickname: Motto: Sterker door strijd (Stronger through Struggle) Location of Rotterdam Coordinates: , Country Province Government  - Mayor Ivo Opstelten  - Aldermen Jeannette Baljeu Hamit Karakus Orhan Kaya Lucas Bolsius Jantine Kriens Dominic Schrijer Roelf de Boer Leonard Geluk Area [1]  - Total 319 km² (123. ... Satellite image of the northwest part of the Rhine-Meuse delta showing river Nieuwe Maas (n). ... National Monument, with the Hotel Krasnapolsky in the right background. ...


Types of dams

Dams can be formed by human agency, natural causes, or even by the intervention of wildlife such as beavers. Man-made dams are typically classified according to their size (height), intended purpose or structure. For other uses, see Beaver (disambiguation). ...


By size

International standards define large dams as higher than 15 meters and major dams as over 150 meters in height.[9]


By purpose

Intended purposes include providing water for irrigation or town or city water supply, improving navigation, creating a reservoir of water to supply industrial uses, generating hydroelectric power, creating recreation areas or habitat for fish and wildlife, flood control and containing effluent from industrial sites such as mines or factories. Few dams serve all of these purposes but some multi-purpose dams serve more than one. Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ... Water supply is the process of self-provision or provision by third parties of water of various qualities to different users. ... Hydroelectricity is electricity produced by hydropower. ... Habitat (which is Latin for it inhabits) is the place where a particular species live and grow. ... A flood (in Old English flod, a word common to Teutonic languages; compare German Flut, Dutch vloed from the same root as is seen in flow, float) is an overflow of water, an expanse of water submerging land, a deluge. ... In the context of creating Plutonium at the Hanford Site, effluent refers to the cooling water that is discharged from a nuclear reactor that may or may not be radioactive. ... This article is about mineral extractions. ...


A saddle dam is an auxiliary dam constructed to confine the reservoir created by a primary dam either to permit a higher water elevation and storage or to limit the extent of a reservoir for increased efficiency. An auxiliary dam is constructed in a low spot or saddle through which the reservoir would otherwise escape. On occasion, a reservoir is contained by a similar structure called a dike to prevent inundation of nearby land. Dikes are commonly used for reclamation of arable land from a shallow lake. This is similar to a levee, which is a wall or embankment built along a river or stream to protect adjacent land from flooding. Afsluitdijk, a 32 km dike in the Netherlands. ... A levee, levée (from the feminine past participle of the French verb lever, to raise), floodbank or stopbank is a natural or artificial slope or wall, usually earthen and often parallels the course of a river. ... Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ...


An overflow dam is designed to be over topped. A weir is a type of small overflow dam that can be used for flow measurement. The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset. ...


A check dam is a small dam designed to reduce flow velocity and control soil erosion. Conversely, a wing dam is a structure that only partly restricts a waterway, creating a faster channel that resists the accumulation of sediment. Severe soil erosion in a wheat field near Washington State University, USA. Erosion is the displacement of solids (soil, mud, rock, and so forth) by the agents of wind, water, ice, or movement in response to gravity. ... A wing dam is a manmade barrier that, unlike a conventional dam, only extends partway into a river. ...


A dry dam is a dam designed to control flooding. It normally holds back no water and allows the channel to flow freely, except during periods of intense flow that would otherwise cause flooding downstream. A dry dam is a dam constructed for the purpose of flood control. ...


A diversionary dam is a structure designed to divert all or a portion of the flow of a river from its natural course. A diversion dam is a type of dam that diverts all or a portion of the flow of a river from its natural course. ... For other uses, see River (disambiguation). ...


By structure

Based on structure and material used, dams are classified as timber dams, arch-gravity dams, embankment dams or masonry dams, with several subtypes. Timber in storage for later processing at a sawmill Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction or wood... San Luis Dam - Embankment dam An Embankment dam is a massive semi-plastic mound of earth and/or rock with a dense, waterproof core. ... Masonry dams are of either the gravity or the arch type. ...


Masonry dams

Arch dams
Hoover Dam, a concrete arch-gravity dam in the Black Canyon of the Colorado River.
Hoover Dam, a concrete arch-gravity dam in the Black Canyon of the Colorado River.
Main article: Arch dam
See also: Geotechnical engineering

In the arch dam, stability is obtained by a combination of arch and gravity action. If the upstream face is vertical the entire weight of the dam must be carried to the foundation by gravity, while the distribution of the normal hydrostatic pressure between vertical cantilever and arch action will depend upon the stiffness of the dam in a vertical and horizontal direction. When the upstream face is sloped the distribution is more complicated. The normal component of the weight of the arch ring may be taken by the arch action, while the normal hydrostatic pressure will be distributed as described above. For this type of dam, firm reliable supports at the abutments (either buttress or canyon side wall) are more important. The most desirable place for an arch dam is a narrow canyon with steep side walls composed of sound rock.[10] The safety of an arch dam is dependent on the strength of the side wall abutments, hence not only should the arch be well seated on the side walls but also the character of the rock should be carefully inspected. This image (C) User:Pcb21, 2003. ... This image (C) User:Pcb21, 2003. ... For the dam near Westerville, Ohio, see Hoover Dam (Ohio). ... Black Canyon, photographed in 1871. ... The Colorado River from the bottom of Marble Canyon, in the Upper Grand Canyon Colorado River in the Grand Canyon from Desert View The Colorado River from Laughlin Horseshoe Bend is a horseshoe-shaped meander of the Colorado River located near the town of Page, Arizona The Colorado River is... dam stands for dekametre. ... Bostons Big Dig presented geotechnical challenges in an urban environment. ... Fluid pressure is the pressure on an object submerged in a fluid, such as water. ... A schematic image of two cantilevers. ... Stiffness is the resistance of an elastic body to deflection or deformation by an applied force. ... A surface normal, or just normal to a flat surface is a three-dimensional vector which is perpendicular to that surface. ... A buttress (and mostly concealed, a flying buttress) supporting walls at the Palace of Westminster Three different types of buttress: diagonal, on the statues plinth; an ordinary buttress supporting a flying buttress, to the right of the statue; a small ordinary buttress to the right side of the picture... Grand Canyon, Arizona Noravank Monastery complex and canyon in Armenia. ...


Two types of single-arch dams are in use, namely the constant-angle and the constant-radius dam. The constant-radius type employs the same face radius at all elevations of the dam, which means that as the channel grows narrower towards the bottom of the dam the central angle subtended by the face of the dam becomes smaller. Jones Falls Dam, in Canada, is a constant radius dam. In a constant-angle dam, also known as a variable radius dam, this subtended angle is kept a constant and the variation in distance between the abutments at various levels are taken care of by varying the radii. Constant-radius dams are much less common than constant-angle dams. Parker Dam is a constant-angle arch dam. Parker Dam is a concrete gravity-arch dam which spans the Colorado river, at a point 155 miles downstream of Hoover Dam. ...


A similar type is the double-curvature or thin-shell dam. Wildhorse Dam near Mountain City, Nevada in the United States is an example of the type. This method of construction minimizes the amount of concrete necessary for construction but transmits large loads to the foundation and abutments. The appearance is similar to a single-arch dam but with a distinct vertical curvature to it as well lending it the vague appearance of a concave lens as viewed from downstream.


The multiple-arch dam consists of a number of single-arch dams with concrete buttresses as the supporting abutments. The multiple-arch dam does not require as many buttresses as the hollow gravity type, but requires good rock foundation because the buttress loads are heavy.


Gravity dams
The Gilboa Dam in the Catskill Mountains of New York State is an example of a "solid" gravity dam.

In a gravity dam, stability is secured by making it of such a size and shape that it will resist overturning, sliding and crushing at the toe. The dam will not overturn provided that the moment around the turning point, caused by the water pressure is smaller than the moment caused by the weight of the dam. This is the case if the resultant force of water pressure and weight falls within the base of the dam. However, in order to prevent tensile stress at the upstream face and excessive compressive stress at the downstream face, the dam cross section is usually designed so that the resultant falls within the middle at all elevations of the cross section (the core). For this type of dam, impervious foundations with high bearing strength are essential. Image File history File links Gilboa_Dam. ... Image File history File links Gilboa_Dam. ... The Schoharie Reservoir is located about 36 miles (57. ... The Catskill Mountains (also known as simply the Catskills), a natural area in New York State northwest of New York City and southwest of Albany are a mature dissected plateau, an uplifted region that was subsequently eroded into sharp relief. ... State nickname: Empire State Other U.S. States Capital Albany Largest city New York Governor George Pataki Official languages None Area 141,205 km² (27th)  - Land 122,409 km²  - Water 18,795 km² (13. ... It has been suggested that this article or section be merged with torque. ... Water pressure is the pressure in any system for supplying water, usually a domestic water system, although the term is used in other contexts as well, such as a municipal water system. ... A Net force (also known as a resultant force) is a vector produced when two or more forces act upon a single object. ... Tensile stress (or tension) is the stress state leading to expansion; that is, the length of a material tends to increase in the tensile direction. ... Compressive stress is the stress applied to materials resulting in their compaction (decrease of volume). ... CORE may refer to: The Congress of Racial Equality in the USA. The Coordinated Online Register of Electors in the United Kingdom. ...


When situated on a suitable site, a gravity dam inspires more confidence in the layman than any other type; it has mass that lends an atmosphere of permanence, stability, and safety. When built on a carefully studied foundation with stresses calculated from completely evaluated loads, the gravity dam probably represents the best developed example of the art of dam building. This is significant because the fear of flood is a strong motivator in many regions, and has resulted in gravity dams being built in some instances where an arch dam would have been more economical. Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ...


Gravity dams are classified as "solid" or "hollow." The solid form is the more widely used of the two, though the hollow dam is frequently more economical to construct. Gravity dams can also be classified as "overflow" (spillway) and "non-overflow." Grand Coulee Dam is a solid gravity dam and Itaipu Dam is a hollow gravity dam. A gravity dam can be combined with an arch dam, an arch-gravity dam, for areas with massive amounts of water flow but less material available for a purely gravity dam. For the town, see Coulee Dam, Washington. ... Part of the Itaipu Dam Itaipu (Guarani: Itaipu, Portuguese: Itaipu, Spanish: Itaipú; pronounced ) is a hydroelectric dam on the Paraná River located on the border between Brazil and Paraguay. ...


Arch-gravity dams

Main article: Arch-gravity dam

Embankment dams

The San Luis Dam near Los Banos, California is an embankment dam.
The San Luis Dam near Los Banos, California is an embankment dam.
Main article: Embankment dam

Embankment dams are made from compacted earth, and have two main types, rock-fill and earth-fill dams. Embankment dams rely on their weight to hold back the force of water, like the gravity dams made from concrete. Image File history File links Metadata Size of this preview: 800 × 596 pixelsFull resolution (2007 × 1496 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 800 × 596 pixelsFull resolution (2007 × 1496 pixel, file size: 1. ... San Luis Dam is a dam that creates San Luis Reservoir, which serves as an off-stream reservoir for the California State Water Project. ... San Luis Dam - Embankment dam An Embankment dam is a massive semi-plastic mound of earth and/or rock with a dense, waterproof core. ... San Luis Dam - Embankment dam An Embankment dam is a massive semi-plastic mound of earth and/or rock with a dense, waterproof core. ... Soil compaction occurs when weight of livestock or heavy machinery compresses the soil, causing it to lose pore space. ...


Rock-fill dams

Rock-fill dams are embankments of compacted free-draining granular earth with an impervious zone. The earth utilized often contains a large percentage of large particles hence the term rock-fill. The impervious zone may be on the upstream face and made of masonry, concrete, plastic membrane, steel sheet piles, timber or other material. The impervious zone may also be within the embankment in which case it is referred to as a core. In the instances where clay is utilized as the impervious material the dam is referred to as a composite dam. To prevent internal erosion of clay into the rock fill due to seepage forces, the core is separated using a filter. Filters are specifically graded soil designed to prevent the migration of fine grain soil particles. When suitable material is at hand, transportation is minimized leading to cost savings during construction. Rock-fill dams are resistant to damage from earthquakes. However, inadequate quality control during construction can lead to poor compaction and sand in the embankment which can lead to liquefaction of the rock-fill during an earthquake. Liquefaction potential can be reduced by keeping susceptible material from being saturated, and by providing adequate compaction during construction. An example of a rock-fill dam is New Melones Dam in California. This article is about the geological substance. ... This article is about the construction material. ... This article is about the natural seismic phenomenon. ... Earthquake liquefaction, often referred to simply as liquefaction, is the process by which saturated, unconsolidated soil or sand is converted into a suspension during an earthquake. ... New Melones Dam is on the Stanislaus River and forms New Melones Lake. ... This article is about the U.S. state. ...


Earth-fill dams

Earth-fill dams, also called earthen, rolled-earth or simply earth dams, are constructed as a simple embankment of well compacted earth. A homogeneous rolled-earth dam is entirely constructed of one type of material but may contain a drain layer to collect seep water. A zoned-earth dam has distinct parts or zones of dissimilar material, typically a locally plentiful shell with a watertight clay core. Modern zoned-earth embankments employ filter and drain zones to collect and remove seep water and preserve the integrity of the downstream shell zone. An outdated method of zoned earth dam construction utilized a hydraulic fill to produce a watertight core. Rolled-earth dams may also employ a watertight facing or core in the manner of a rock-fill dam. An interesting type of temporary earth dam occasionally used in high latitudes is the frozen-core dam, in which a coolant is circulated through pipes inside the dam to maintain a watertight region of permafrost within it. San Luis Dam - Embankment dam An Embankment dam is a massive semi-plastic mound of earth and/or rock with a dense, waterproof core. ... Look up Homogeneous in Wiktionary, the free dictionary. ... For other uses, see Clay (disambiguation). ... A hydraulic fill is an embankment or other fill in which the materials are deposited in place by a flowing stream of water, with the deposition being selective. ... While these two men dig in Alaska to study soil, the hard permafrost requires the use of a jackhammer In geology, permafrost or permafrost soil is soil at or below the freezing point of water (0 °C or 32 °F) for two or more years. ...


Because earthen dams can be constructed from materials found on-site or nearby, they can be very cost-effective in regions where the cost of producing or bringing in concrete would be prohibitive. This makes it better for the environment too.


Asphalt-Concrete Core

A third type of embankment dam is built with asphalt concrete core. The majority of such dams are built with rock and/or gravel as the main fill material. Almost 100 dams of this design have now been built world-wide since the first such dam was completed in 1962. All asphalt-concrete core dams built so far have an excellent performance record. The type of asphalt used is a viscoelastic-plastic material that can adjust to the movements and deformations imposed on the embankment as a whole, and to settlements in the foundation. The flexible properties of the asphalt make such dams especially suited in earthquake regions. Asphalt As shown in this cross-section, many older roadways are smoothed by applying a thin layer of asphalt concrete to the existing portland cement concrete. ... A viscoelastic material is one in which: hysteresis is seen in the stress-strain curve. ... For other uses, see Plastic (disambiguation). ... The term asphalt is often used as an abbreviation for asphalt concrete. ... This article is about the natural seismic phenomenon. ...


Cofferdams

A cofferdam during the construction of locks at the Montgomery Point Lock and Dam.
A cofferdam during the construction of locks at the Montgomery Point Lock and Dam.

A cofferdam is a (usually temporary) barrier constructed to exclude water from an area that is normally submerged. Made commonly of wood, concrete or steel sheet piling, cofferdams are used to allow construction on the foundation of permanent dams, bridges, and similar structures. When the project is completed, the cofferdam may be demolished or removed. See also causeway and retaining wall. Common uses for cofferdams include construction and repair of off shore oil platforms. In such cases the cofferdam is fabricated from sheet steel and welded into place under water. Air is pumped into the space, displacing the water allowing a dry work environment below the surface. Upon completion the cofferdam is usually deconstructed unless the area requires continuous maintenance. Image File history File links Dam, coffer, Montgomery Point Lock and Dam. ... Image File history File links Dam, coffer, Montgomery Point Lock and Dam. ... Canal locks in England. ... dam stands for dekametre. ... This article is about the construction material. ... For other uses, see Steel (disambiguation). ... Look up Pile in Wiktionary, the free dictionary. ... A foundation is a structure that transmits loads from a building or road to the underlying ground. ... The Hindenburgdamm rail causeway across the Wadden Sea to the island of Sylt in Schleswig-Holstein, Germany In modern usage, a causeway is a road or railway elevated by a bank, usually across a broad body of water or wetland. ... A gravity-type stone retaining wall A retaining wall is a structure that holds back soil or rock from a building, structure or area. ...


Timber dams

A timber crib dam in Michigan, photographed in 1978.
A timber crib dam in Michigan, photographed in 1978.

Timber dams were widely used in the early part of the industrial revolution and in frontier areas due to ease and speed of construction. Rarely built in modern times by humans due to relatively short lifespan and limited height to which they can be built, timber dams must be kept constantly wet in order to maintain their water retention properties and limit deterioration by rot, similar to a barrel. The locations where timber dams are most economical to build are those where timber is plentiful, cement is costly or difficult to transport, and either a low head diversion dam is required or longevity is not an issue. Timber dams were once numerous, especially in the North American west, but most have failed, been hidden under earth embankments or been replaced with entirely new structures. Two common variations of timber dams were the crib and the plank. Image File history File links Download high resolution version (4823x3853, 2396 KB) Summary Redridge Timber Crib Dam, Salmon Trout River, Beacon Hill, Houghton County, MI Source: jpeg compession of 18MB tiff found here. ... Image File history File links Download high resolution version (4823x3853, 2396 KB) Summary Redridge Timber Crib Dam, Salmon Trout River, Beacon Hill, Houghton County, MI Source: jpeg compession of 18MB tiff found here. ... This article is about the U.S. State. ... Timber in storage for later processing at a sawmill Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction or wood... For other uses, see Cement (disambiguation). ...


Timber crib dams were erected of heavy timbers or dressed logs in the manner of a log house and the interior filled with earth or rubble. The heavy crib structure supported the dam's face and the weight of the water.


Timber plank dams were more elegant structures that employed a variety of construction methods utilizing heavy timbers to support a water retaining arrangement of planks.


Very few timber dams are still in use. Timber, in the form of sticks, branches and withes, is the basic material used by beavers, often with the addition of mud or stones. For other uses, see Beaver (disambiguation). ...


Steel dams

Red Ridge steel dam, b. 1905, Michigan.
Red Ridge steel dam, b. 1905, Michigan.

A steel dam is a type of dam briefly experimented with in around the turn of the 19th-20th Century which uses steel plating (at an angle) and load bearing beams as the structure. Intended as permanent structures, steel dams were an (arguably failed) experiment to determine if a construction technique could be devised that was cheaper than masonry, concrete or earthworks, but sturdier than timber crib dams. Image File history File links Download high resolution version (1024x818, 114 KB) Summary This image was found at the Library of Congress HAER archive entry with the original caption: VIEW LOOKING AT UPSTREAM SIDE OF DAM. HAER MICH,31-BEHIL,1-1 It is a part of the Historic American... Image File history File links Download high resolution version (1024x818, 114 KB) Summary This image was found at the Library of Congress HAER archive entry with the original caption: VIEW LOOKING AT UPSTREAM SIDE OF DAM. HAER MICH,31-BEHIL,1-1 It is a part of the Historic American... A Steel dam is a type of dam (a structure to impound or retard the flow of water) that is made of steel, rather than the more common masonry, earthworks, concrete or timber construction materials. ...


Beaver dams

Main article: Beaverdam (habitat)

Beavers create dams primarily out of mud and sticks to flood a particular habitable area. By flooding a parcel of land, beavers can navigate below or near the surface and remain relatively well hidden or protected from predators. The flooded region also allows beavers access to food, especially during the winter.


Construction elements

Power generation plant

Main article: Hydroelectricity

As of 2005, hydroelectric power, mostly from dams, supplies some 19% of the world's electricity, and over 63% of renewable energy.[11] Much of this is generated by large dams, although China uses small scale hydro generation on a wide scale and is responsible for about 50% of world use of this type of power.[11] Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Kaplan turbine and electrical generator cut-away view. ... This article is about machines that produce electricity. ... Hydroelectricity is electricity produced by hydropower. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ...


Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator; to boost the power generation capabilities of a dam, the water may be run through a large pipe called a penstock before the turbine. A variant on this simple model uses pumped storage hydroelectricity to produce electricity to match periods of high and low demand, by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Potential energy can be thought of as energy stored within a physical system. ... Kaplan turbine and electrical generator cut-away view. ... This article is about machines that produce electricity. ... Penstocks at the Grand Coulee Dams third powerhouse. ... A Siemens steam turbine with the case opened. ... Diagram of the TVA pumped storage facility at Racoon Mountain Pumped storage hydroelectricity is a method of storing and producing electricity to supply high peak demands. ... The Ashokan Reservoir, located in Ulster County, New York, USA. It is one of 19 that supplies New York City with drinking water. ...


Spillways

Spillway on Llyn Brianne dam, Wales soon after first fill.
Spillway on Llyn Brianne dam, Wales soon after first fill.
Main article: Spillway

A psaun is a section of a dam designed to pass water from the upstream side of a dam to the downstream side. Many spillways have floodgates designed to control the flow through the spillway. Types of spillway include: A service spillway or primary spillway passes normal flow. An auxiliary spillway releases flow in excess of the capacity of the service spillway. An emergency spillway is designed for extreme conditions, such as a serious malfunction of the service spillway. A fuse plug spillway is a low embankment designed to be over topped and washed away in the event of a large flood. Download high resolution version (966x1404, 431 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (966x1404, 431 KB) Wikipedia does not have an article with this exact name. ... Llyn Brianne spillway immdiately after filling Llyn Brianne is a man made lake or reservoir in the headwaters of the River Tywi. ... This article is about the country. ... Spillway of Llyn Brianne dam in Wales A Spillway is a structure used to provide for the controlled release of flood flows from a dam or levee into a downstream area, typically being the river that has been dammed. ... Tokyo floodgates to protect from typhoon surges. ... A fuse plug is a collapsible dam installed on spillways in dams to increase the dams capacity. ...


Fusegate elements are independant free-standing block set side by side on the spillway which work without any remote control. They allow to increase the normal pool of the dam without compromising the security of the dam because they are designed to be gradually evacuated for exceptionnal events. They work as fixed weir most of the time allowing overspilling for the common floods.


The spillway can be gradually eroded by water flow, including cavitation or turbulence of the water flowing over the spillway, leading to its failure. It was the inadequate design of the spillway which led to the 1889 over-topping of the South Fork Dam in Johnstown, Pennsylvania, resulting in the infamous Johnstown Flood (the "great flood of 1889"). For morphological image processing operations, see Erosion (morphology). ... Cavitating propeller model in a water tunnel experiment High speed jet of fluid impact on a fixed surface. ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... The South Fork Dam was located on Lake Conemaugh, an artificial body of water located near South Fork, Pennsylvania. ... Nickname: Location of Pennsylvania within the USA Johnstown, Cambria County, Pennsylvania, U.S.A. Coordinates: , Country State County Cambria Government  - Mayor Tom Trigona Area  - City  6. ... This article is about the U.S. State. ... The Johnstown Flood disaster (or Great Flood of 1889 as it became known locally) occurred on May 31, 1889. ...


Erosion rates are often monitored, and the risk is ordinarily minimized, by shaping the downstream face of the spillway into a curve that minimizes turbulent flow, such as an ogee curve. Ogee is a shape consisting of a concave arc flowing into a convex arc, so forming an S-shaped curve with vertical ends. ...


Dam creation

Common purposes

Function Example
Power generation Hydroelectric power is a major source of electricity in the world. many countries have rivers with adequate water flow, that can be dammed for power generation purposes. For example, the Itaipu on the Paraná River in South America generates 14 GW and supplied 93% of the energy consumed by Paraguay and 20% of that consumed by Brazil as of 2005.
Stabilize water flow / irrigation Dams are often used to control and stabilize water flow, often for agricultural purposes and irrigation.[12] Others such as the Berg Strait dam can help to stabilize or restore the water levels of inland lakes and seas, in this case the Aral Sea.[13]
Flood prevention Dams such as the Blackwater dam of Webster, New Hampshire and the Delta Works are created with flood control in mind.[14]
Land reclamation Dams (often called dykes or levees in this context) are used to prevent ingress of water to an area that would otherwise be submerged, allowing its reclamation for human use.
Water diversion See: diversion dam.

Hydroelectric dam diagram The waters of Llyn Stwlan, the upper reservoir of the Ffestiniog Pumped-Storage Scheme in north Wales, can just be glimpsed on the right. ... Part of the Itaipu Dam Itaipu (Guarani: Itaipu, Portuguese: Itaipu, Spanish: Itaipú; pronounced ) is a hydroelectric dam on the Paraná River located on the border between Brazil and Paraguay. ... The sun rising over the Paraná River, from the north-east of Rosario, Argentina. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... For other uses, see Watt (disambiguation). ... Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ... The Aral Sea (Kazakh: Арал Теңізі, Aral Tengizi, Uzbek: , Russian: Аральскοе мοре) is a landlocked endorheic sea in Central Asia; it lies between Kazakhstan in the north and Karakalpakstan, an autonomous region of Uzbekistan, in the south. ... Webster is a town located in Merrimack County, New Hampshire. ... For other uses, see New Hampshire (disambiguation). ... The Delta Works are a number of constructions that were built between 1950 and 1997 in the southwest of the Netherlands to protect a large area of land from the sea. ... Afsluitdijk, a 32 km dike in the Netherlands. ... A levee, levée (from the feminine past participle of the French verb lever, to raise), floodbank or stopbank is a natural or artificial slope or wall, usually earthen and often parallels the course of a river. ... Land reclamation is either of two distinct practices. ... A diversion dam is a type of dam that diverts all or a portion of the flow of a river from its natural course. ...

Siting (location)

One of the best places for building a dam is a narrow part of a deep river valley; the valley sides can then act as natural walls. The primary function of the dam's structure is to fill the gap in the natural reservoir line left by the stream channel. The sites are usually those where the gap becomes a minimum for the required storage capacity. The most economical arrangement is often a composite structure such as a masonry dam flanked by earth embankments. The current use of the land to be flooded should be dispensable. For other uses, see River (disambiguation). ... Fljótsdalur in East Iceland, a rather flat valley In geology, a valley (also called a vale or dale) is a depression with predominant extent in one direction. ... This article refers to the building structure component; for the fraternal organization, see Freemasonry. ...


Significant other engineering and engineering geology considerations when building a dam include: Engineering is the discipline of acquiring and applying knowledge of design, analysis, and/or construction of works for practical purposes. ... Engineering Geology is the application of the science of geology to the understanding of geologic phenomena and the engineering solution of geologic hazards and other geologic problems for society. ...

  • permeability of the surrounding rock or soil
  • earthquake faults
  • landslides and slope stability
  • peak flood flows
  • reservoir silting
  • environmental impacts on river fisheries, forests and wildlife (see also fish ladder)
  • impacts on human habitations
  • compensation for land being flooded as well as population resettlement
  • removal of toxic materials and buildings from the proposed reservoir area

In the earth sciences, permeability (commonly symbolized as κ, or k) is a measure of the ability of a material (typically, a rock or unconsolidated material) to transmit fluids. ... This article is about the natural seismic phenomenon. ... This entry refers to the geological term landslide. ... Figure 1: Simple slope slip section The field of slope stability encompasses the analysis of static and dynamic stability of slopes of earth and rock-fill dams, slopes of other types of embankments, excavated slopes, and natural slopes in soil and soft rock. ... Dams are built all over the world for purposes such as hydroelectricity, retaining and re-directing water flow. ... Pool-and-weir fish ladder at Bonneville Dam on the Columbia River Fishways, most commonly referred to as fish ladders but also known as fish passes, are structures placed on or around man-made barriers (such as dams and weirs) to assist the natural migration of diadromous fishes. ...

Impact assessment

Impact is assessed in several ways: the benefits to human society arising from the dam (agriculture, water, damage prevention and power), the harm or benefits to nature and wildlife (especially fish and rare species), the impact on the geology of an area - whether the change to water flow and levels will increase or decrease stability, and the disruption to human lives (relocation, loss of archeological or cultural matters underwater). The Siberian Tiger is a subspecies of tiger that are critically endangered. ... Archaeology or sometimes in American English archeology (from the Greek words αρχαίος = ancient and λόγος = word/speech) is the study of human cultures through the recovery, documentation and analysis of material remains, including architecture, artefacts, biofacts, human remains, and landscapes. ...


Environmental impact

Wood and garbage accumulated because of a dam
Wood and garbage accumulated because of a dam
Main article: Environmental impacts of dams

Dams affect many ecological aspects of a river. Rivers depend on the constant disturbance of a certain tolerance. Dams slow the river and this disturbance may damage or destroy this pattern of ecology. Temperature is also another problem that dams create. Rivers tend to have fairly homogeneous temperatures. Reservoirs have layered temperatures, warm on the top and cold on the bottom; in addition often it is water from the colder (lower) layer which is released downstream, and this may have a different dissolved oxygen content than before. Organisms depending upon a regular cycle of temperatures may be unable to adapt; the balance of other fauna (especially plant life and microscopic fauna) may be affected by the change of oxygen content. Image File history File links Metadata Size of this preview: 796 × 599 pixelsFull resolution‎ (2,592 × 1,952 pixels, file size: 1. ... Image File history File links Metadata Size of this preview: 796 × 599 pixelsFull resolution‎ (2,592 × 1,952 pixels, file size: 1. ... Dams are built all over the world for purposes such as hydroelectricity, retaining and re-directing water flow. ... Oxygen saturation or dissolved oxygen (DO) is a measure of amount of oxygen dissolved in a given medium. ... Fauna is a collective term for animal life of any particular region or time. ...


Water exiting a turbine usually contains very little suspended sediment, which can lead to scouring of river beds and loss of riverbanks; for example, the daily cyclic flow variation caused by the Glen Canyon Dam was a contributor to sand bar erosion. Glen Canyon Dam on 19 June 2005. ... In geography, a bar is a linear shoaling landform feature within a body of water. ... For morphological image processing operations, see Erosion (morphology). ...


Older dams often lack a fish ladder, which keeps many fish from moving up stream to their natural breeding grounds, causing failure of breeding cycles or blocking of migration paths.[15] Even the presence of a fish ladder does not always prevent a reduction in fish reaching the spawning grounds upstream. In some areas, young fish ("smolt") are transported downstream by barge during parts of the year. Turbine and power-plant designs that have a lower impact upon aquatic life are an active area of research. Pool-and-weir fish ladder at Bonneville Dam on the Columbia River Fishways, most commonly referred to as fish ladders but also known as fish passes, are structures placed on or around man-made barriers (such as dams and weirs) to assist the natural migration of diadromous fishes. ... Frog spawn Spawning is the production or depositing of eggs in large numbers by aquatic animals. ... Self propelled barge carrying bulk crushed stone A barge is a flat-bottomed boat, built mainly for river and canal transport of heavy goods. ...


A large dam can cause the loss of entire ecospheres, including endangered and undiscovered species in the area, and the replacement of the original environment by a new inland lake. Ecosphere has several different meanings: In astronomy an ecosphere is an imaginary shell of space surrounding stars where conditions are such that life might survive. ... The Siberian Tiger is a subspecies of tiger that are critically endangered. ... Cryptids are creatures presumed extinct, hypothetical species, or creatures known from anecdotal evidence and/or other evidence insufficient to prove their existence with scientific certainty. ...


Depending upon the circumstances, a dam can either reduce or increase the net production of greenhouse gases. An increase can occur if the reservoir created by the dam itself acts as a source of substantial amounts of potent greenhouse gases (methane and carbon dioxide) due to plant material in flooded areas decaying in an anaerobic environment. According to the World Commission on Dams report, 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 a conventional oil-fired thermal generation plant.[16] A decrease can occur if the dam is used in place of traditional 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, carbon monoxide, dust, and mercury from coal). Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Methane is a chemical compound with the molecular formula . ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... It has been suggested that Anoxic sea water, Oxygen minimum zone, and Hypoxic zone be merged into this article or section. ... The combustion product gas resulting from the burning of fossil fuels (or any other combustible fuel) is called flue gas. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... R-phrases , , , , S-phrases , , , Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Nitric oxide or Nitrogen monoxide is a chemical compound with chemical formula NO. This gas is an important signaling molecule in the body of... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... This article is about the element. ... Coal Example chemical structure of coal Coal is a fossil fuel formed in ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ...


Human social impact

The impact on human society is also significant. For example, the Three Gorges Dam on the Yangtze River in China, is more than five times the size of the Hoover Dam (U.S.) and will create a reservoir 600 km long, to be used for hydro-power generation. Its construction required the loss of over a million people's homes and their mass relocation, the loss of many valuable archaeological and cultural sites, as well as significant ecological change.[17] The Three Gorges Dam (simplified Chinese: ; traditional Chinese: ; pinyin: ) is a Chinese hydroelectric river dam that spans the Yangtze River in Sandouping, Yichang, Hubei, China. ... The Yangtze River or Chang Jiang (Simplified Chinese: ; Traditional Chinese: ; Pinyin: ), or Drichu in Tibetan (Tibetan: འབ; Wylie: bri chu) is the longest river in Asia and the third longest in the world, after the Nile in Africa, and the Amazon in South America. ... For the dam near Westerville, Ohio, see Hoover Dam (Ohio). ... For other uses of terms redirecting here, see US (disambiguation), USA (disambiguation), and United States (disambiguation) Motto In God We Trust(since 1956) (From Many, One; Latin, traditional) Anthem The Star-Spangled Banner Capital Washington, D.C. Largest city New York City National language English (de facto)1 Demonym American...


Economics

Construction of a hydroelectric plant requires a long lead-time for site studies, hydrological studies, and environmental impact assessment, and are large scale projects by comparison to traditional power generation based upon fossil fuels. The number of sites that can be economically developed for hydroelectric production is limited; new sites tend to be far from population centers and usually require extensive power transmission lines. Hydroelectric generation can be vulnerable to major changes in the climate, including variation of rainfall, ground and surface water levels, and glacial melt, causing additional expenditure for the extra capacity to ensure sufficient power is available in low water years. Fossil fuels or mineral fuels are fossil source fuels, that is, hydrocarbons found within the top layer of the earth’s crust. ... Power transmission is the movement of energy from its place of generation to a location where it is applied to performing useful work. ... It has been suggested that this article or section be merged with Spirit leveling. ...


Once completed, if it is well designed and maintained, a hydroelectric power source is usually comparatively cheap and reliable. It has no fuel and low escape risk, and as a renewable energy source it is cheaper than both nuclear and wind power.[citation needed] It is more easily regulated to store water as needed and generate high power levels on demand, compared to wind power. Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... An example of a wind turbine. ...


Dam failure

The reservoir emptying through the failed Teton Dam.
The reservoir emptying through the failed Teton Dam.
International special sign for works and installations containing dangerous forces
International special sign for works and installations containing dangerous forces

Dam failures are generally catastrophic if the structure is breached or significantly damaged. Routine deformation monitoring of seepage from drains in, and around, larger dams is necessary to anticipate any problems and permit remedial action to be taken before structural failure occurs. Most dams incorporate mechanisms to permit the reservoir to be lowered or even drained in the event of such problems. Another solution can be rock grouting - pressure pumping portland cement slurry into weak fractured rock. Description: Water pouring out of the reservoir of the Teton Dam in Idaho following its catastrophic failure on June 5, 1976. ... Description: Water pouring out of the reservoir of the Teton Dam in Idaho following its catastrophic failure on June 5, 1976. ... This article needs additional references or sources for verification. ... Image File history File links International_special_sign_for_works_and_installations_containing_dangerous_forces. ... Image File history File links International_special_sign_for_works_and_installations_containing_dangerous_forces. ... Deformation monitoring is the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result of the application of stress to it. ... Grout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints (like those between tiles). ... Sampling fast set Portland cement Portland cement is the most common type of cement in general usage, as it is a basic ingredient of concrete, mortar and plaster. ... A slurry is in general a thick suspension of solids in a liquid and may be: Look up slurry in Wiktionary, the free dictionary. ...


During an armed conflict, a dam is to be considered as an "installation containing dangerous forces" due to the massive impact of a possible destruction on the civilian population and the environment. As such, it is protected by the rules of International Humanitarian Law (IHL) and shall not be made the object of attack if that may cause severe losses among the civilian population. To facilitate the identification, a protective sign consisting of three bright orange circles placed on the same axis is defined by the rules of IHL. International humanitarian law (IHL), also known as the law of war, the laws and customs of war or the law of armed conflict, is the legal corpus comprised of the Geneva Conventions and the Hague Conventions, as well as subsequent treaties, case law, and customary international law. ... Protective signs are symbols to be used during an armed conflict to mark persons and objects under the protection of various treaties of International Humanitarian Law (IHL). ...


The main causes of dam failure include spillway design error (South Fork Dam), geological instability caused by changes to water levels during filling or poor surveying (Vajont Dam, Malpasset), poor maintenance, especially of outlet pipes (Lawn Lake Dam, Val di Stava Dam Collapse), extreme rainfall (Shakidor Dam), and human, computer or design error (Buffalo Creek Flood, Dale Dike Reservoir, Taum Sauk pumped storage plant). The South Fork Dam was located on Lake Conemaugh, an artificial body of water located near South Fork, Pennsylvania. ... Vajont Dam is a dam completed in 1961 under Mount Toc, 100 km north of Venice, Italy. ... Malpasset was an arch dam near Fréjus on the Côte dAzur, France. ... The flood caused by the failure of Lawn Lake Dam scoured Roaring River valley and deposited an alluvial fan of debris in Horseshoe Park. ... The destruction in the valley On July 19, 1985 a tailings dam collapsed in Stava, Italy. ... Wikinews has related news: Shakidor Dam bursts in Pakistan after heavy rain The Shakidor (Shadi Kor) dam is located near Pasni, in the Balochistan province of south west Pakistan, 1,900 km (1,180 miles) from Islamabad and has a length of about 148 meters (485 feet). ... Aerial View of Buffalo Creek area taken the day after impoundment dam #3 failed. ... Dale Dike Reservoir Dale Dike Reservoir or Dale Dyke Reservoir (grid reference SK240913) is a reservoir in the northeast Peak District, in South Yorkshire, England. ... An aerial photo of the upper reservoir of the Taum Sauk plant. ...


A notable case of deliberate dam failure (prior to the above ruling) was the British Royal Air Force Dambusters raid on Germany in World War II (codenamed "Operation Chastise"), in which three German dams were selected to be breached in order to have an impact on German infrastructure and manufacturing and power capabilities deriving from the Ruhr and Eder rivers. This raid later became the basis for several films. RAF redirects here. ... Operation Chastise was the official name for the attacks on German dams on May 17, 1943 in World War II using a specially developed bouncing bomb. The attack was carried out by Royal Air Force No. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Combatants No. ... For the conurbation see Ruhr Area. ... The Eder is a river in Germany (ca. ...

Further information: List of dam failures

The reservoir emptying through the failed Teton Dam International special sign for works and installations containing dangerous forces A dam is a barrier across flowing water that obstructs, directs or slows down the flow, often creating a reservoir, lake or impoundments. ...

Notes

  1. ^ Guinness Book of Records 1997 Pages 108-109 ISBN 0-85112-693-6
  2. ^ The American Heritage® Dictionary of the English Language, Fourth Edition
  3. ^ Source: Tijdschrift voor Nederlandse Taal- en Letterkunde (Magazine for Dutch Language and Literature), 1947. The first known appearance of the word dam stems from 1165. However, there is one village, Obdam, that is already mentioned in 1120. The word seems to be related to the Greek word taphos, meaning grave or grave hill. So the word should be understood as dike from dug out earth. The names of more than 40 places (with minor changes) from the Middle Dutch era (1150 - 1500 CE) such as Amsterdam (founded as 'Amstelredam' in the late 12th Century) and Rotterdam, also bear testimony to the use of the word in Middle Dutch at that time.
  4. ^ According to Joseph Needham.
  5. ^ Science and Civilization in China, Joseph Needham, 1946, page 368, http://books.google.com/books?id=l6TVhvYLaEwC&pg=RA1-PA138&lpg=RA1-PA138&dq=needham+ceylon&source=web&ots=m_8OpjaZdL&sig=2Ir6nKuKbFqXJe9Z1lSiDlJW5Rk#PRA2-PA368,M1
  6. ^ a b Mohamed Bazza (28-30). overview of the hystory of water resources and irrigation management in the near east region (english). Retrieved on 2007-08-01.
  7. ^ a b Wiebe, Bijker (2007). "Dikes and Dams, Thick with Politics". Isis 98: 109-123. Retrieved on 2007-07-01. 
  8. ^ Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 3. Taipei: Caves Books, Ltd.
  9. ^ Methodology and Technical Notes (HTML) (English). Watersheds of the World. Retrieved on 2007-08-01. “A large dam is defined by the industry as one higher than 15 meters high and a major dam as higher than 150.5 meters.”
  10. ^ Arch Dam Forces. Retrieved on 2007-01-07.
  11. ^ a b Renewables Global Status Report 2006 Update, REN21, published 2006, accessed 2007-05-16
  12. ^ The Impact of Agricultural Development on Aquatic Systems and its Effect on the Epidemiology of Schistosomes in Rhodesia (PDF) (English). IUCN. “Recently, agricultural development has concentrated on soil and water conservation and resulted in the construction of a multitude of dams of various capacities which tend to stabilize water flow in rivers and provide a significant amount of permanent and stable bodies of water.”
  13. ^ Kazakhstan (HTML) (English). Land and Water Development Division (1998). Retrieved on 2007-08-01. “construction of a dam (Berg Strait) to stabilize and increase the level of the northern part of the Aral Sea.”
  14. ^ Blackwater Dam (HTML) (English). US Army Corps of Engineers. “The principal objective of the dam and reservoir is to protect downstream communities”
  15. ^ Dam Fact Sheet
  16. ^ Hydroelectric power's dirty secret revealed - earth - 24 February 2005 - New Scientist
  17. ^ "Three Gorges dam wall completed", china-embassy, 20 May 2006. Retrieved on 2006-05-21. 

For other uses, see Amsterdam (disambiguation). ... Nickname: Motto: Sterker door strijd (Stronger through Struggle) Location of Rotterdam Coordinates: , Country Province Government  - Mayor Ivo Opstelten  - Aldermen Jeannette Baljeu Hamit Karakus Orhan Kaya Lucas Bolsius Jantine Kriens Dominic Schrijer Roelf de Boer Leonard Geluk Area [1]  - Total 319 km² (123. ... Joseph Terence Montgomery Needham (December 9, 1900 – March 24, 1995) was a British biochemist and pre-eminent authority on the history of Chinese science. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 213th day of the year (214th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 213th day of the year (214th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 7th day of the year in the Gregorian calendar. ... REN21 is the Renewable Energy Policy Network for the 21st Century: a global policy network that provides a forum for international leadership on renewable energy. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 213th day of the year (214th in leap years) in the Gregorian calendar. ... is the 140th day of the year (141st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 141st day of the year (142nd in leap years) in the Gregorian calendar. ...

See also

Wikimedia Commons has media related to:
Look up dam in Wiktionary, the free dictionary.

Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... For other uses, see Beaver (disambiguation). ... The Delta Works are a number of constructions that were built between 1950 and 1997 in the southwest of the Netherlands to protect a large area of land from the sea. ... Canal locks in England. ... John McPhees profile of David Brower (the archdruid) and some of his natural enemies. ... The List of reservoirs and dams is a link page for any reservoir or dam in the world, by continent. ... This article does not cite any references or sources. ... A megaproject is a very large investment project. ... Combatants No. ... The 32 km long Afsluitdijk separates the IJsselmeer from the North Sea, protecting thousands of km² of land. ...

External links

Canadian Geographic is the bimonthly magazine of the Royal Canadian Geographical Society (RCGS). ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... The temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time. ... Instrumental global surface temperature measurements; see also [http://www. ... Comparison of ground based (blue) and satellite based (red: UAH; green: RSS) records of temperature variations since 1979. ... The temperature record of the past 1000 years describes the reconstruction of temperature for the last 1000 years on the Northern Hemisphere. ... 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In IPCC reports, equilibrium climate sensitivity refers to the equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration. ... Global dimming is the gradual reduction in the amount of global direct irradiance at the Earths surface that was observed for several decades after the start of systematic measurements in 1950s. ... Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. ... Wikinews has related news: Scientists warn thawing Siberia may trigger global meltdown A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... The Keeling Curve is a graph measuring the increase in the levels of carbon dioxide in the atmosphere since 1958. ... Land Use, Land-Use Change and Forestry (LULUCF) is a term often used in climate change topics. ... Tokyo, a case of Urban Heat Island. ... For other uses, see Albedo (disambiguation). ... Cloud forcing (sometimes described as cloud radiative forcing) is the difference between the radiation budget components for average cloud conditions and cloud-free conditions. ... A glaciation (a created composite term meaning Glacial Period, referring to the Period or Era of, as well as the process of High Glacial Activity), often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ... Global cooling in general can refer to a cooling of the Earth. ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ... Milankovitch cycles are the collective effect of changes in the Earths movements upon its climate, named after Serbian civil engineer and mathematician Milutin Milanković. The eccentricity, axial tilt, and precession of the Earths orbit vary in several patterns, resulting in 100,000 year ice age cycles of the... Orbital forcing, or Milankovitch theory, describes the effect on climate of slow changes in the tilt of the Earths axis and shape of the orbit. ... The generalised concept of radiative forcing in climate science is any change in the radiation (heat) entering the climate system or changes in radiatively active gases. ... 400 year history of sunspot numbers. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... General Circulation Models (GCMs) are a class of computer-driven models for weather forecasting and predicting climate change, where they are commonly called Global Climate Models. ... The politics of global warming looks at the current political issues relating to global warming, as well as the historical rise of global warming as a political issue. ... UNFCCC logo. ... IPCC is the science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), to evaluate the risk of climate change brought on by humans, based mainly on... The global warming controversy is a dispute regarding the nature and consequences of global warming. ... This article lists scientists and former scientists who have stated disagreement with one or more of the principal conclusions of the mainstream scientific assessment of global warming. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ... Graphical description of risks and impacts from global warming from the Third Assessment Report of the Intergovernmental Panel on Climate Change. ... This article or section does not cite any references or sources. ... Fields outside Benambra, Victoria, Australia suffering from drought conditions A drought is an extended period of months or years when a region notes a deficiency in its water supply. ... As recent estimates of the rate of global warming have increased, so have the financial estimates of the damage costs. ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ... A view down the Whitechuck Glacier in North Cascades National Park in 1973 The same view as seen in 2006, where this branch of glacier retreated 1. ... The extinction risk of climate change -- that is, the expected number of species expected to become extinct due to the effects of global warming -- has been estimated in a 2004 Nature study to be between 15 and 37 percent of known species by 2050. ... Global monthly average total ozone amount Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earths stratosphere since around 1980; and a much larger, but seasonal, decrease in stratospheric ozone over Earths... Change in sea surface pH caused by anthropogenic CO2 between the 1700s and the 1990s Ocean acidification is the name given to the ongoing decrease in the pH of the Earths oceans, caused by their uptake of anthropogenic carbon dioxide from the atmosphere. ... Sea level measurements from 23 long tide gauge records in geologically stable environments show a rise of around 20 centimeters per century (2 mm/year). ... Shutdown or slowdown of the thermohaline circulation is a possible effect of global warming. ... Global carbon dioxide emissions 1800–2000 Global average surface temperature 1850 to 2006 Mitigation of global warming involves taking actions aimed at reducing the extent of global warming. ... Kyoto Protocol Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ... CDM directs here. ... Joint implementation (JI) is an arrangement under the Kyoto Protocol allowing industrialised countries with a greenhouse gas reduction commitment (so-called Annex 1 countries) to invest in emission reducing projects in another industrialised country as an alternative to emission reductions in their own countries. ... The European Climate Change Programme (ECCP) was launched in June 2000 by the European Unions European Commission. ... The United Kingdoms Climate Change Programme was launched in November 2000 by the British government in response to its commitment agreed at the 1992 United Nations Conference on Environment and Development (UNCED). ... Crude oil prices, 1994-2007 (not adjusted for inflation) In 2005 the government of Sweden announced their intention to make Sweden the first country to break its dependence on petroleum, natural gas and other ‘fossil raw materials’ by 2020. ... Emissions trading (or cap and trade) is an administrative approach used to control pollution by providing economic incentives for achieving reductions in the emissions of pollutants. ... Emissions trading schemes (also known as ‘cap and trade’ schemes) are one of the policy instruments available for reducing carbon dioxide (CO2) and other greenhouse gases. ... A carbon tax is a tax on energy sources which emit carbon dioxide into the atmosphere. ... Until recently, most carbon offsets were commonly done by planting trees. ... This article deals with carbon credits for international trading. ... A carbon dioxide (CO2) sink is a carbon reservoir that is increasing in size, and is the opposite of a carbon dioxide source. The main natural sinks are (1) the oceans and (2) plants and other organisms that use photosynthesis to remove carbon from the atmosphere by incorporating it into... For the physical concepts, see conservation of energy and energy efficiency. ... Efficient energy use, sometimes simply called energy efficiency, is using less energy to provide the same level of energy service. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... Renewable energy commercialization involves three generations of technologies dating back more than 100 years. ... // Renewable energy development covers the advancement, capacity growth, and use of renewable energy sources by humans. ... The soft energy path is an energy use and development strategy delineated and promoted by some energy experts and activists, such as Amory Lovins and Tom Bender; in Canada, David Suzuki has been a very prominent (if less specialized) proponent. ... The G8 Climate Change Roundtable was formed in January 2005 at the World Economic Forum in Davos. ... The issue of human-caused, or anthropogenic, climate change (global warming) is becoming a central focus of the Green movement. ... Adaptation to global warming covers all actions aimed at reducing the negative effects of global warming. ... The Seven Rila Lakes in Rila, Bulgaria are typical representatives of lakes with glacial origin A glacial lake is a lake with origins in a melted glacier. ... Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ... A rainwater tank is a water tank which is used to collect and store rainwater runoff, typically from rooftops. ... Sustainable development is a socio-ecological process characterized by the fulfilment of human needs while maintaining the quality of the natural environment indefinitely. ... A tornado in central Oklahoma. ... Global carbon dioxide emissions 1800–2000 Global average surface temperature 1850 to 2006 Avoiding Dangerous Climate Change: A Scientific Symposium on Stabilisation of Greenhouse Gases was a 2005 international conference that redefined the link between atmospheric greenhouse gas concentration, and the 2°C (3. ... LADSS or Land Allocation Decision Support System, is an agricultural land use planning tool being developed at The Macaulay Institute. ... This article serves as a glossary of the most common terms and how they are used. ...

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Encyclopedia4U - Dam - Encyclopedia Article (1105 words)
Dams may be built to provide water for irrigation or town water supply, control the amount of water in rivers or to provide hydroelectric power.
Rock-fill dams are embankments of loose rock with either a watertight upstream face of concrete slabs or timber or a watertight core.
Earth dams are constructed as a simple homogeneous embankment of well-compacted earth, sometimes with a watertight concrete core or upstream face, or sometimes with a hydraulic fill to produce a watertight core.
dam. The Columbia Encyclopedia, Sixth Edition. 2001-05 (520 words)
Single-arch dams are curved upstream and are usually constructed in narrow canyons or gorges where the rocky side walls are strong enough to withstand the tremendous lateral thrust of the dam that is caused by the pressure of the water.
Dams may also be constructed with roller-compacted concrete, in which thin layers of concrete are compacted as if they were earth layers; this produces a far stronger dam, without the need for full forms.
The Oroville Dam, located in California, the tallest in the United States, is 770 ft (235 m) high; the Rogun Dam, in Russia, the tallest in the world, is 1,100 ft (335 m) high.
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