The Mosul Dam http://commons.wikimedia.org/wiki/File:Mosul_Dam_hydro_power_plant.jpg Iraq's largest dam is at the epicenter of fierce fighting between ISIS and the Kurdish Peshmerga. But whoever ends up holding the dam will face a serious challenge just ensuring that the neglected dam does not fail.

Kurdish forces currently hold the Mosul Dam, according to the dam's director. However, even if the Kurds maintain their control over the dam, the dam's structural flaws and poor state of maintenance present a serious risk to all of down-river Iraq.

The Army Corps of Engineers found in 2007 that the dam had an exceptionally high probability of failure. If the dam were to collapse, it could kill an estimated half-million people from flooding, power outages, loss of farmland, and eventual drought. According to the New Yorker, the capital of Baghdad could see about 15 feet of water.

The dam was originally constructed atop a bed of highly soluble gypsum which began to dissolve even before the construction of the dam was finished. The dissolution of the gypsum was actually noticed during construction in the 1980s — during the rule of dictator Saddam Hussein, whom the dam was named after for a time — and preventative measures were put in place.

But these measures failed and the dam now needs to be grouted continuously just to prevent the bedrock from dissolving beneath the dam. The grouting process involves injecting materials into the base of a dam to prevent water seepage, requiring considerable skill and technical expertise.

"It's been under continuous grouting since the 1980s," Richard Coffman, an assistant professor of civil engineering at the University of Arkansas who has conducted research on the Mosul Dam, told Business Insider. "The dam is grouted six times a week to prevent it from failing."

Without this grouting, the dam's base will eventually dissolve.

"It would be a pretty rapid dissolution of the dam given the constant grouting. I can't give an exact time, but the frequency of the grouting makes me believe that the dissolution would occur quickly," Coffman said.

According to Coffman, Mosul could be flooded with up to 30 meters of water within three and a half hours of the dam's failure.

Baghdad would be subsumed in five meters of water within three days.

"Around 50% of the city of Mosul would be inundated with water," Coffman told BI. "The cropland and farmland would also be flooded and washed away."

Should ISIS take control of the dam, unleashing its water could be part of the jihadist group's overall strategy in the country. In January 2014, ISIS took control of the Fallujah Dam for four months. While in control, ISIS triggered flooding that reached almost to Baghdad and caused a water shortage for hundreds of thousands of Iraqis.

And thanks to the dam's poor construction and grouting issues, ISIS could also inadvertently cause flooding without even meaning to.

"Grouting is typically a learned skill done by experts," Coffman said. "I can't speak to the skill of the insurgents, but I'd imagine that they might have some trouble with this."

Permanent solutions to the dam's various engineering issues have been attempted, but have so far been ineffective, according to Coffman.

Here's a look and how a dam break would affect all of Iraq (and reach Baghdad) by flooding the Tigris river:



