Dam
Dam
This article is about structures for water impoundment. For other uses, see Dam (disambiguation).
Glen Canyon Dam
A sideview of the Lake Vyrnwy dam, in Wales, finished in 1888
Karapuzha Dam, an earth dam in the Indian state of Kerala
A small dam near Groningen, Netherlands
A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions.
The word dam can be traced back to Middle English,[1] and before that, from Middle Dutch, as seen in the names of many old cities.[2] The first known appearance of dam occurs in 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".[citation needed] 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.
History Edit
Ancient dams Edit
Early dam building took place in Mesopotamia and the Middle East. Dams were used to control the water level, for Mesopotamia's weather affected the Tigris and Euphrates rivers.
The earliest known dam is the Jawa Dam in Jordan, 100 kilometres (62 mi) northeast of the capital Amman. This gravity dam featured an originally 9-metre-high (30 ft) and 1 m-wide (3.3 ft) stone wall, supported by a 50 m-wide (160 ft) earth rampart. The structure is dated to 3000 BC.[3][4]
The Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km (16 mi) south of Cairo, was 102 m (335 ft) long at its base and 87 m (285 ft) wide. The structure was built around 2800[5] or 2600 BC[6] as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards.[5][6] During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III and Amenmehat IV dug a canal 16 km (9.9 mi) long linking the Fayum Depression to the Nile in Middle Egypt. Two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. The lake called "Mer-wer" or Lake Moeris covered 1,700 km2 (660 sq mi) and is known today as Berkat Qaroun.[citation needed]
By the mid-late third millennium BC, an intricate water-management system within Dholavira in modern-day India was built. The system included 16 reservoirs, dams and various channels for collecting water and storing it.[7]
One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen. Initiated somewhere between 1750 and 1700 BC, it was made of packed earth – triangular in cross section, 580 m (1,900 ft) in length and originally 4 m (13 ft) high – running between two groups of rocks on either side, to which it was linked by substantial stonework. Repairs were carried out during various periods, most important around 750 BC, and 250 years later the dam height was increased to 7 m (23 ft). After the end of the Kingdom of Saba, the dam fell under the control of the Ḥimyarites (~115 BC) who undertook further improvements, creating a structure 14 m (46 ft) high, with five spillway channels, two masonry-reinforced sluices, a settling pond, and a 1,000 m (3,300 ft) canal to a distribution tank. These extensive works were not actually finalized until 32
This article is about structures for water impoundment. For other uses, see Dam (disambiguation).
Glen Canyon Dam
A sideview of the Lake Vyrnwy dam, in Wales, finished in 1888
Karapuzha Dam, an earth dam in the Indian state of Kerala
A small dam near Groningen, Netherlands
A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions.
The word dam can be traced back to Middle English,[1] and before that, from Middle Dutch, as seen in the names of many old cities.[2] The first known appearance of dam occurs in 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".[citation needed] 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.
History Edit
Ancient dams Edit
Early dam building took place in Mesopotamia and the Middle East. Dams were used to control the water level, for Mesopotamia's weather affected the Tigris and Euphrates rivers.
The earliest known dam is the Jawa Dam in Jordan, 100 kilometres (62 mi) northeast of the capital Amman. This gravity dam featured an originally 9-metre-high (30 ft) and 1 m-wide (3.3 ft) stone wall, supported by a 50 m-wide (160 ft) earth rampart. The structure is dated to 3000 BC.[3][4]
The Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km (16 mi) south of Cairo, was 102 m (335 ft) long at its base and 87 m (285 ft) wide. The structure was built around 2800[5] or 2600 BC[6] as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards.[5][6] During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III and Amenmehat IV dug a canal 16 km (9.9 mi) long linking the Fayum Depression to the Nile in Middle Egypt. Two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. The lake called "Mer-wer" or Lake Moeris covered 1,700 km2 (660 sq mi) and is known today as Berkat Qaroun.[citation needed]
By the mid-late third millennium BC, an intricate water-management system within Dholavira in modern-day India was built. The system included 16 reservoirs, dams and various channels for collecting water and storing it.[7]
One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen. Initiated somewhere between 1750 and 1700 BC, it was made of packed earth – triangular in cross section, 580 m (1,900 ft) in length and originally 4 m (13 ft) high – running between two groups of rocks on either side, to which it was linked by substantial stonework. Repairs were carried out during various periods, most important around 750 BC, and 250 years later the dam height was increased to 7 m (23 ft). After the end of the Kingdom of Saba, the dam fell under the control of the Ḥimyarites (~115 BC) who undertook further improvements, creating a structure 14 m (46 ft) high, with five spillway channels, two masonry-reinforced sluices, a settling pond, and a 1,000 m (3,300 ft) canal to a distribution tank. These extensive works were not actually finalized until 32
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