Mosul Dam

Mosul Dam
Location of Mosul Dam
Location	45 mi north of Mosul, Ninawa Governorate, Iraq
Coordinates	36°37′49″N 42°49′23″E / 36.63028°N 42.82306°E / 36.63028; 42.82306Coordinates: 36°37′49″N 42°49′23″E / 36.63028°N 42.82306°E / 36.63028; 42.82306
Construction began	1980
Opening date	1986
Construction cost	US$1.5 billion
Operator(s)	Ministry of Water Resources (17 August 2014)[1]
Dam and spillways
Impounds	Tigris River
Height	113 m (371 ft)[2]
Length	3.4 km (2.1 mi)
Spillways	2
Spillway type	Service: Controlled chute Emergency: Fuse-plug ogee
Spillway capacity	Service: 13,000 m3/s (460,000 cu ft/s) Emergency: 4,000 m3/s (140,000 cu ft/s)
Reservoir
Total capacity	11,100,000,000 m3 (8,998,916 acre·ft)
Active capacity	8,100,000,000 m3 (6,566,777 acre·ft)
Normal elevation	300 m (980 ft)
Power station
Commission date	Mosul 1: 1986 Mosul 2: 1985 Mosul 3: 1989
Turbines	Mosul 1: 4 x 187.5 MW (251,400 hp) Francis-type Mosul 2: 4 x 15.5 MW (20,800 hp) Kaplan-type Mosul 3: 2 x 120 MW (160,000 hp) Francis pump-turbine[3][4]
Installed capacity	1,052 MW (1,411,000 hp)
Annual generation	3,420 gigawatt-hours (12,300 TJ)

Mosul Dam (Arabic: سد الموصل‎, Kurdish: Bêndawi Mûsil) or Chambarakat Dam, formerly known as Saddam Dam (سد صدام), is the largest dam in Iraq. It is located on the Tigris River in the western governorate of Ninawa, upstream of the city of Mosul. At full capacity, the hydroelectric dam holds about 11.1 cubic kilometres (2.7 cu mi) of water and provides electricity to the 1.7 million residents of Mosul. The dam's main 750 megawatts (1,010,000 hp) power station contains four 187.5 megawatts (251,400 hp) Francis turbine-generators. A pumped-storage hydroelectricity power plant with a capacity of 250 megawatts (340,000 hp) and a run-of-the-river dam downstream with a 62-megawatt (83,000 hp) capacity also belong to the Mosul Dam scheme. It is ranked as the fourth largest dam in the Middle East, measured by reserve capacity, capturing snowmelt from Turkey, some 70 miles (110 km) north.^[5] Built on a karst foundation, concerns over the dam's instability have led to major remediation and rehabilitation efforts since the 2003 invasion of Iraq.

Construction

Historical Castle of Aski Mosul before being submerged by the dam's reservoir

In order to bolster Saddam Hussein's regime during the Iran-Iraq War and promote Saddam's Arabization efforts in Northern Iraq, the construction of the Mosul Dam was important. Construction on the Mosul Dam began in 1980 by a German-Italian consortium that was led by Hochtief Aktiengesellschaft. Because the dam was constructed on a foundation of soluble gypsum, the engineers installed a grouting gallery that would allow continuous grouting of the dam's foundation in order to promote stability. Construction was complete in 1984 and in the spring of 1985, the Mosul Dam began to inundate the Tigris River, filling the reservoir which submerged many archaeological sites in the region. Because of significant structural stability issues associated with the Mosul Dam, grouting and additional construction and repairs are constant.^[6][7]

Instability and remediation

The earthen embankment dam is located on top of gypsum, a soft mineral which dissolves in contact with water. Continuous maintenance is required to plug, or "grout", new leaks with a liquefied slurry of cement and other additives.^[8] More than 50,000 tonnes (49,000 long tons; 55,000 short tons) of material have been injected into the dam since leaks began forming shortly after the reservoir was filled in 1986, and 24 machines currently continuously pump grout into the dam base. A September 2006 report by the United States Army Corps of Engineers noted, "In terms of internal erosion potential of the foundation, Mosul Dam is the most dangerous dam in the world." The report further outlined a worst-case scenario, in which a sudden collapse of the dam would flood Mosul under 65 feet (20 m) of water and Baghdad, a city of 7 million, to 15 feet (4.6 m), with an estimated death toll of 500,000.^[9] A report on 30 October 2007 by the US Special Inspector General for Iraq Reconstruction (SIGIR) said that the dam's foundations could give way at any moment.^[10]

In 2004, dam manager Abdulkhalik Thanoon Ayoub ordered the dam's water level, which can reach 330 feet (101 m) above sea level, to have a maximum of 319 feet (97 m), thus reducing the pressure on the structure. Nevertheless, Iraqi officials maintain that the U.S. government is overstating the risk. The Army Corps of Engineers has proposed that the Badush Dam under construction downstream be expanded to obstruct the large wave which would result if the Mosul Dam collapsed. This has been resisted by Iraqi officials, who note that the current plan for the Badush Dam is US$300 million to provide hydroelectric power and help irrigation while the proposed expansion would cost $10 billion.^[9]

In 2007, the U.S. Army Corps of Engineers developed and executed a US$27 million plan to help continue maintenance and repairs on the dam in the short-term. The Iraq Government is implementing a long-term solution which includes the construction of 67 m (220 ft) deep walls around the dam foundation. The ongoing project is expected to cost $4 billion and last four to five years.^[6]

Demolition concerns during the 2003 invasion

Chute spillway with ski jump section to dissipate the energy of the rushing water

In early April 2003, following the invasion of Iraq by a U.S.-led coalition, military intelligence had developed several scenarios, including one in which Iraqi forces had wired the dam for detonation. This would, like a dam collapse, release the 110-metre (360 ft) high waterline of the lake reservoir, to reach Mosul in about two hours. Subsequent investigation found nearly 500 dam workers to still be at work nearly a month after pay had stopped being distributed, with security being provided by militia under the Patriotic Union of Kurdistan.^[5]

Richard A. Muller, a physicist and JASON Defense Advisory Group consultant on U.S. national security, wrote:

2014 takeover of dam by ISIL

For several weeks in July and August Islamic State of Iraq and the Levant (ISIL) held Mosul Dam.^[11] On August 7, 2014, the movement captured the complex from the Peshmerga. ISIL control of the dam created fears that its power supply could be restricted or its water flows to downstream areas greatly inhibited. In a less likely scenario, there were worries the dam could be breached, causing widespread flooding and destruction downstream.^[12][13]

On August 17, 2014, Peshmerga and the Iraqi Army launched a successful operation to retake control of the dam from ISIL militants. United States air strikes assisted the Kurdish and Iraqi military, damaging or destroying 19 vehicles belonging to ISIL, as well as a checkpoint near the dam.^[14]

Notes and references

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