Putting the Dam in Damocles: Iraq’s Largest Dam at Risk of Collapse

On 10 June 2014, the Islamic State (IS) occupied Mosul, Iraq’s second largest city. Since then, ethnic and religious minorities have been prosecuted while IS institutes its bloody and bizarre interpretation of Islamic law. However, IS may not actually be the biggest threat in the vicinity of Mosul. Upstream of Mosul itself, the Mosul dam blocks the Tigris River, holding back the floodwaters which used to irrigate the Fertile Crescent. At 113 meters high and 3.4 kilometres wide, it is the largest dam in Iraq, and the fourth largest in the Middle East. It is a multipurpose dam, both providing water for irrigation and generating hydroelectricity for the residents of Mosul.

Image courtesy of Rehman Abubakr, ©2012, some rights reserved.
Image courtesy of Rehman Abubakr, ©2012, some rights reserved.

However, the dam has required constant maintenance ever since it was built. The dam is built on a karst topography: the bedrock is almost entirely gypsum, slowly which dissolves in water. Such topographies create dramatic landscapes, with caves and sinkholes. But they also create unstable foundations, particularly for large structures built on top of them. Engineers first noticed the problem when constructing the dam, but the time and money it would have taken to implement a long-term solution were denied by Saddam Hussein. Instead, engineers installed a gallery from where the base of the dam could be continuously re-grouted.  According to the Washington Post, ‘Twenty-four clanging machines churn 24 hours a day to pump grout deep into the dam’s base. And sinkholes form periodically as the gypsum dissolves beneath the structure.’

This continual maintenance keeps the dam from catastrophic failure. However, maintenance has not been continuous. Concerns about the integrity of the dam were first raised in 2007, leading the US Army Corp of Engineers (who at the time were largely responsible for the dam) to call it ‘the most dangerous dam in the world.’

This problem came to a head in the summer of 2014, when IS briefly gained control of the dam. In addition to fears that IS would use the dams water as a weapon, there were concerns that adequate maintenance would not take place while the dam was under IS control. While it is unknown how well IS took care of the dam, the situation has only gotten worse, with one recent report saying ‘All information gathered in the last year indicates Mosul Dam is at a significantly higher risk of failure than originally understood and is at a higher risk of failure today than it was a year ago.’

Iraqi officials have publically denied reports that the dam is a danger; one official was surprised by the report, saying ‘I was only 20 when I first started working here and now my hair is turning all white. But the dam is exactly as it always was.’ While officials acknowledge that certain areas of the dam may need minor repairs, they also say that allegations that the dam is at risk of catastrophic failure are overblown.

However, even if the probability of collapse is minute, the risk of Mosul dam is too great to ignore. According to a factsheet published by the US embassy in Baghdad, should the dam break

The floodwave would resemble an in-land tidal wave between Mosul and Samarra’, and would sweep downstream anything in its path, including bodies, buildings, cars, unexploded ordinances, hazardous chemicals, and waste… Flooding south of Samarra would resemble that of Hurricane Katrina, with standing water that pervades much of Baghdad for weeks to months. As floodwaters recede, mud and waste-covered remnants of previous infrastructure will be left behind… Flood water could reach depths greater than 45 feet in some parts of Mosul City in as little as one to four hours, giving residents little time to flee… Flood water could reach Tikrit in one to two days… Flood water could reach Baghdad in three to four days and have depths of up to 33 feet in the river channel.

The failure of the Mosul dam would be a catastrophe of an entirely new order of magnitude. Between 500,000 and 1,470,000 would be at risk of immediate death. In the long term, most or Iraq’s farmland is also located in the Tigris river basin, and so would be destroyed, possibly leading to wide spread food shortages in the medium term. While aid actors would mobilise to provide assistance, the destruction of infrastructure and the predicted months of standing water would make providing help very difficult. The flooding also threatens Baghdad airport, which is one of the main arteries through which aid could be provided. Perhaps most threateningly, the report notes that ‘the floodwave could dislodge and redeposit IEDs,’ which would further delay any aid response.

In short, the potential exists for a disastrous situation. The very fact that the state department released the factsheet, which criticises Iraqi policy regarding the dam, implies that State Department feels the threat of the dam is not being taken seriously. Publically releasing the factsheet, rather than distributing it through diplomatic channels indicated that US officials are growing ever more concerned over Iraqi inaction regarding the dam.

In theory, there exists a plan to repair the dam: the Iraqi government has announced a deal with an Italian engineering firm named Trevi to conduct major overhauls on certain areas of the dam. The deal also includes the deployment of 450 Italian troops to defend the dam. However, a month has passed since the announcement, and no formal contract has yet been signed. Substantive repairs to the dam are further complicated by the nearby presence of IS controlled territory. IS forces introduce an element of uncertainty to any project which attempts to repair the dam. While an offensive to drive IS from Mosul has been announced, hopes are not high that the offensive will actually take place before 2017.

While IS control of Mosul is no doubt a humanitarian tragedy, there exists potential for a much greater tragedy to strike. Should the Mosul dam fail, almost the entirety of the Tigris floodplain could be under water within a few days. While the actual probability of a catastrophic failure is low, the magnitude of the consequences mean that serious efforts need to be made to repair the dam. It can’t wait.

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