If the dam ruptured, it would likely cause a catastrophe of Biblical proportions, loosing a wave as high as a hundred feet that would roll down the Tigris, swallowing everything in its path for more than a hundred miles. Large parts of Mosul would be submerged in less than three hours. Along the riverbanks, towns and cities containing the heart of Iraq’s population would be flooded; in four days, a wave as high as sixteen feet would crash into Baghdad, a city of six million people. “If there is a breach in the dam, there will be no warning,” Alwash said. “It’s a nuclear bomb with an unpredictable fuse.”
The U.S. Embassy’s report on the Mosul Dam envisions .... [that] a “tsunami-like wave” would rush through Mosul, carrying away everything in its path, including bodies, buildings, cars, unexploded bombs, hazardous chemicals, and human waste. The wave would almost certainly catch most of the people trying to outrun it. Residents of Mosul, scrambling on foot and by car through a citywide traffic jam, would need to travel at least three and a half miles to survive. In less than an hour, those who remained would be under as much as sixty feet of water.
|Satellite View of Mosul Dam|
By the time the flood wave rolled past Baghdad and exhausted itself, as many as one and a half million people could be dead. But, some experts told me, the aftermath would prove even more harrowing. “I am not really worried about the dead—because they’re dead,” Alwash said. “What worries me is everyone else. How do you feed six million people in Baghdad when it’s flooded? How do you give them electricity? Where do they go?”So, what's the reason for concern about the Mosul Dam?
Completed in 1984, the dam sits on a foundation of soluble rock. To keep it stable, hundreds of employees have to work around the clock, pumping a cement mixture into the earth below. Without continuous maintenance, the rock beneath would wash away, causing the dam to sink and then break apart. But Iraq’s recent history has not been conducive to that kind of vigilance.The maintenance consists of constant, daily drilling through the floor of the dam into the bedrock and then pumping cement into the fissures and cavities, some as big as a house, where the rock has dissolved away.
Even with constant maintenance, a feat made difficult by government lassitude and the fact that the dam is in a war zone, it's not clear that engineers are able to stay ahead of the problem. Indeed, some engineers who have worked for years on the dam are convinced that it's just a matter of time until it breaches and that such a calamity is likely to happen sooner rather than later.
Filkins' essay is very interesting and is worth the time it takes to read. Apparently, if the dam he writes about does collapse it could easily create the biggest disaster, man-made or natural, in human history.