There have been reports in the past week or two about a large dam in the vicinity of Mosul that has developed cracks and is (probably) about to fail. Voices of Iraq reported on this danger on August 10th.

A major disaster is looming in northern Iraq because the wall of the Mosul Dam that holds back the Tigris river north of Mosul city is in danger of imminent collapse, a report by the Independent newspaper said on Wednesday.

Quoting experts, the newspaper said that flood waters could destroy 70% of Ninewa province and "inflict heavy damage 190 miles (300km) downstream along the Tigris." According to the report, "This would mean heavy damage to cities such as Tikrit and Samarra and the floods could reach as far as Baghdad."

Citing "fundamental and irreversible flaws existing in the dam's foundation," a recent report by the US Army Corps of Engineers indicated that the safety of the dam against a potential catastrophic collapse "cannot be guaranteed."

Suggesting possible solutions, the report said "The main method used to strengthen the foundations of the Mosul dam is pumping liquid cement into it or grouting. But a US-funded study [ed: noted below] concluded that grouting would not save the dam, although it did need to be continued and enhanced 'to reduce the probability of failure.'"

"An international panel of experts called in by the Ministry of Water Resources in Baghdad concluded that a limit should also be placed on the level of the water in the reservoir - that was done in April last year," read the report.

The Mosul Dam, built between 1980 and 1984, has long been known to be in a "dangerous condition because of unstable bedrock," the newspaper said.

Frequent commenter Dubhaltach noted in comments to another article here:

Radio Sawa is American owned and we include their reports for compeleteness. (There was a hell of debate about doing that - a debate that got quite heated when it was first suggested.)

You can find the story here if only to see a photo of part of the dam. The green zone government water minister held a press conference yesterday denying that the dam was in danger of collapse and saying that there were no cracks in it. He also said that the 26 machines shoring up the base of the dam by pumping in cement worked 24 hours a day.

The engineer in charge of the project said that fixing the cracks in the dam's base is a three stage project that involves constructing bulwarks, reducing strain by reducing the amount of water it holds back and by constructing other dams.

If you’re fluent in Arabic, you can go here and read the story. If not, we’ll just have to wait until Gorilla’s Guides translates it.

This is not a “new” crisis. The dam was listed as endangered back in 2003, when we first conquered Iraq.

For weeks military intelligence on the Mosul Dam, a major hydroelectric and irrigation impoundment in northern Iraq, had delivered a variety of scenarios, none of them good for coalition efforts to rebuild Iraq. One version in early April indicated that Iraqi forces had wired the structure for detonation. Another more recent report claimed the dam's foundation was "leaking like a sieve and ready to collapse."

Either case would set in motion a cascade of catastrophe, unleashing as much as 12.5 billion cu m of water pooled behind the 3.2-km-long earth-filled impoundment thundering down the Tigris River Valley toward Mosul, the second largest city in Iraq. The wave behind the 110-m-high crest would take about two hours to reach the city of 1.7 million. Telecommunications systems operated sporadically even before the war; how much advance warning the victims would have these days is anybody's guess.[emph added]

Does everyone understand a “110 m-high-crest” is about one football field, including endzones?

The US Army Corps of Engineers reported back in late 2005 about ongoing repairs, indicating the work was scheduled to be completed in 2006.