A review of history of such ancient countries as China, India, Iran and Egypt will show that building dams dates back to more than 4,000 years ago and has been the base of those civilizations. The idea of storing water by building small or big dams was not specific to Iranian people and many ancient civilizations have used dams. However, in terms of historical background, Iran is one of pioneer countries in this regard. The following are major instances of dams built in Iran. Kebar Dam The first arch dam of the world, which is still being used, was built many centuries ago. The dam is located 130 km from Saveh dam and Qom city, has been built over Kebar river, and is about 700 years old. The dam is 26 m high with a crown length of 55 m and an arch diameter of 38 m. Its body is made of hard gravel stone with a covering of mortar and rocks that have locked the two ends of the arch to both sides of the valley. The mortar used is Sarouj (a combination of sand, lime, coal powder and egg white). The dam is like figure 'seven' in Persian language and its surrounding mountains are made of limestone. Kebar dam is an arch dam with a fixed radius and is one of the oldest arch dams in the world, which indicates efficiency of engineers at that time. Saveh Dam This dam has been built over Qara Chai River, 30 km southwest of Saveh in Vafarqan valley and was being used before the new dam was built. Since during Safavid era, the dam underwent basic repairs, it is known as Abbasi Dam too (named after Shah Abbas from Safavid dynasty). The dam is 18 m high with a pool volume of 25 million cu. m. The dam is a gravitational dam and is made of gravel stone and sarouj mortar. They say since the dam was built on alluvial layers, when the pooling was complete water penetrated through the topmost part of the dam and its young architect who was not able to find a solution, committed suicide. The common point between Saveh and Kebar dams is the height of both dams that have been apparently built to store water. This method of irrigation by storing water at time of high precipitation and dispensing it when there is need to water, had no precedence in Iran up to that date. Both dams have spillways and it seems that they have been both built at the same time. It must be noted that the new Saveh dam has been constructed and made operational on the same river. Kerit Dam Since 2,000 years ago up to the 20th century, the world's highest arch dams were built in Iran (Izadkhast in Fars, Kebar in Qom and Kerit in Tabas). Kerit dam with a height of 60 m was the world's tallest arch dam for 550 years and was a feat of construction engineering of the world. The dam has been built in four stages and its crown has a width of only 2.1 m. Kerit dam lacks spillways and based on estimates it must have experienced 1,000 instance of spillovers. The important point is that the dam was not significantly damaged during Tabas earthquake. The former head of International Committee of Large Dams has termed construction of Kerit dam as the most amazing human achievement in the Middle Ages. Kerit dam is located 42 km from Tabas and 28 km from Kerit village. Golpayegan Dam Golpayegan dam was the first earthen reservoir dam of the country, which enjoys a clay core and has been made on a bed of shale stone. Golpayegan dam is located 25 km southwest of Golpayegan near Akhtovan village on Qomroud River. The dam aims at preventing flood damages and supplying agricultural water to 6,000 hectares farmlands in the region. Technical equipment and welfare facilities were limited at the time the dam was built. However, through round-the-clock efforts made by its builders, it enjoys satisfactory safety and stability 43 years after it has been built and is currently the most important source of agricultural water for farmlands in Golpayegan region. Despite the fact that a whole week of bitter cold has brought construction operations to a standstill and though working in such a narrow space is different and needs many preparations, 211 cu. m. concrete has been cast in water. Total volume of the dam's pool is 45 million cu. m. and useful volume of its reservoir is 42 million cu. m. Amir Kabir (Karaj) Dam Construction of Amir Kabir dam started in 1957 and it was made operational in 1961. The dam has been built over Karaj River and over a basin with an area of 764 sq. km. with average annual water flow of 472 million cu. m. It is located 63 km northwest of Tehran. The dam means to control spring floods, prevent flood damages, supply potable water to Tehran and generate hydropower. Amir Kabir Dam is a reservoir, concrete dam with two arches and its height is 180 m from foundation. The dam was the first reservoir dam around Tehran. Karkheh Dam Kharkheh dam is Iran's biggest and the world's sixth longest dam with a crown length of 3,030 m. The dam was the first large dam in Iran that was designed and implemented by Iranians and the first managerial experience of Iranian contractors in dam building industry that was completed by more than 120 contractor and eight consultant companies. Karkheh dam, which straddles Karkheh River, aims to regulate and supply needed water for irrigating 340,000 hectares downstream lands, controlling destructive floods and preventing resultant damages as well as producing 924 gigawatt hours hydropower per year. Karkheh River is Iran's third biggest river after Karoun and Dez rivers from the viewpoint of water output. Dams Built on Karoun River Karoun River originates from South Zagros Mountains in Kuhrang, Armand, Kharsan, Vanak, and Bazaft regions and after going a distance of 800 km along northeast to south and west joins Arvand River in Khorramshahr before pouring into Persian Gulf. It is Iran's biggest river in terms of water output. Average long-term water output of Karoun River at the site of dam is 453 cu. m. per second and its annual water flow is more than 14 billion cu. m. Seven large chain dams are being built over this river that include Karoun 1, Karoun 2, Karoun 3, Karoun 4, Karoun 5, Masjed Soleiman and Gotvand Olya dams and power plants. Karoun 3 Karoun 3 dam and power plant in Khuzestan province is located 250 km east of Ahvaz and has been built on Karoun River. The goal of the project is to control floods and regulate about one billion cu. m. water for agricultural use as well as annual production of 4,137 kWh electricity. The dam is a double arch concrete dam with a total pool volume of 2,750 million cu. m. while its underground tunnels are about 21.5 km long. Karoun 4 Karoun 4 reservoir dam is located in Chaharmahal - Bakhtiari province located 180 km southwest of Shahr-e Kord and 670 km from estuary of the river in Persian Gulf. The goal of the project is to take advantage of the river's potential and generating 2,107 gigawatt hours hydropower while helping other chain dams in controlling river's floods and supplying needed water for industries and agriculture in Khuzestan plain. The dam is a double arch dam with total pool volume of 2,190 million cu. m. and a useful pool volume of 748.7 million cu. m. Gotvand Olya This dam is located 380 km from Karoun River's estuary, 25 km north of Shushtar city near the Gotvand town. It is the last high dam to be built over Karoun River. The goals of the project include annual generation of 4,250 million kWh hydropower, controlling seasonal floods of Karoun River as well as water overflowing upstream dams, regulating needed downstream water and creating tourism attractions. The dam is an earthen dam with a clay core and total pool volume of about 4.5 billion cu. m. All the said dams are being built by Iranian engineers by taking advantage of the latest technical know-how from within and without the country. (Gostareshe Sanaat Monthly, Sept 25, 2004)