The Dukan Dam (Sorani Kurdish: بەنداوی دووکان Arabic: سد دوكان) is a multi-purpose concrete arch dam in As Sulaymaniyah Governorate, Kurdistan Region of Iraq. It impounds the Little Zab, thereby creating Lake Dukan. The Dukan Dam was built between 1954 and 1959 whereas its power station became fully operational in 1979. The dam is 360 metres (1,180 ft) long and 116.5 metres (382 ft) high and its hydroelectric power station has a maximum capacity of 400 MW.

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Dukan (Dokan) Dam
Location of Dukan (Dokan) Dam in Iraq
Location	As Sulaymaniyah Governorate, Kurdistan Region
Coordinates	35°57′15″N 44°57′10″E
Status	Operational
Construction began	1954
Opening date	1959
Operator(s)	Ministry of Water Resources
Dam and spillways
Type of dam	Cylindrical arch
Impounds	Little Zab
Height	116.5 m (382 ft)
Length	360 m (1,180 ft)
Elevation at crest	516 m (1,693 ft)
Width (crest)	6.2 m (20 ft)
Width (base)	34.3 m (113 ft)
Dam volume	370,000 m3 (480,000 cu yd)
Spillways	2
Spillway type	Service: Tunnel Emergency: Bell-mouth
Spillway capacity	Service: 2,450 m3/s (86,521 cu ft/s) Emergency: 1,860 m3/s (65,685 cu ft/s)
Reservoir
Creates	Lake Dukan
Total capacity	6,970,000,000 m3 (5,650,671 acre⋅ft)[1]
Active capacity	6,100,000,000 m3 (4,945,350 acre⋅ft)
Inactive capacity	790,000,000 m3 (640,463 acre⋅ft)
Catchment area	11,690 km2 (4,514 sq mi)
Surface area	270 km2 (104 sq mi)
Normal elevation	511 m (1,677 ft)
Power Station
Commission date	1979
Hydraulic head	95 m (312 ft) (rated)
Turbines	5 x 80 MW Francis-type[2]
Installed capacity	400 MW

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The Dukan Dam was built between 1954 and 1959 as a multi-purpose dam to provide water storage, irrigation and hydroelectricity.^[3] The design for the dam was carried out by the British engineering company Binnie & Partners^[4] (with Partner and third generation Binnie engineer Geoffrey Binnie the key engineer).^[5] Additional structural analysis was done for Binnie by his friends at Imperial College, Professor Pippard and Letitia Chitty, who "developed a stress analysis technique using relaxation methods and a rubber model to verify the design form."^[6]

Prior to the flooding of Lake Dukan, the area was subjected to archaeological research to investigate as many archaeological sites as possible. An archaeological survey in the Ranya Plain documented some 40 archaeological sites with evidence for occupation ranging from the sixth millennium BCE up to the present. Five of these sites were then excavated: Tell Bazmusian, ed-Dem, Kamarian, Qarashina and Tell Shemshara. The excavations at Tell Bazmusian revealed a temple dating to the second millennium BCE.^[7] At Tell Shemshara, an early-sixth millennium BCE village was excavated, as well as an early-second millennium BCE palace with a small archive of clay tablets.^[8][9] The inhabitants of some 50 villages in the flooded area, around 1,000–1,200 families, were resettled to the west of the lake.^[10] The power station was designed in 1973 by the Russian company Hydroproject and became operational in 1979.

In 1990 the dam was used to house a group of 'human shield' hostages. They were held initially at the guest lodge nearby, thereafter in the offices adjacent to the cafeteria inside the dam and later inside prefabricated huts on the top of the dam. The intention was to deter coalition air strikes in the upcoming 1991 Gulf war. They were released in December 1990 and returned home.^[11]

Due to lack of maintenance and repairs, the power station has underperformed and is now, after 30 years of service, due for replacement.^[4][12] In 2007, the World Bank began a US$40 million project to repair the Dokan and Darbandikhan Dams. Repairs to the Dokan Dam are expected to cost over $8 million and be complete in late 2012.^[13]

The Dukan Dam is a multi-purpose concrete arch dam abutted by gravity monoliths. It is 360 metres (1,180 ft) long and 116.5 metres (382 ft) high. At its base it is 32.5 metres (107 ft) wide, tapering off to 6.2 metres (20 ft) at the top.^[10][14] The combined maximum discharge of the dam is 4,300 cubic metres (150,000 cu ft) per second. This is divided over a spillway tunnel with three radial gates having a combined maximum discharge of 2,440 cubic metres (86,000 cu ft) per second, and an emergency bell mouth spillway with a capacity of 1,860 cubic metres (66,000 cu ft) per second. Two irrigation outlets with a combined discharge of 220 cubic metres (7,800 cu ft) per second have not been operated over the last ten years. The powerhouse of five Francis units at 80 MW each releases between 110 and 550 cubic metres (3,900 and 19,400 cu ft) per second.^[14] Lake Dukan, the reservoir created by the Dukan Dam, has a surface area of 270 square kilometres (100 sq mi). Its anticipated capacity is 6.8 cubic kilometres (1.6 cu mi) with a maximum of 8.3 cubic kilometres (2.0 cu mi).^[10]

• List of dams and reservoirs in Iraq