Iraq’s Most Dangerous Dam Still Operating, Under ISIS Control

— -- Employees at the Mosul Dam in Iraq, which is under the control of a brutal group of Islamist fighters, are still producing electricity and carrying out vital daily grouting operations, temporarily mitigating fears of a breach that could launch a 65-foot wall of water into the country's largest cities and send flood waters all the way to Baghdad.

The lead dam engineer and his team, along with their families, are still on site and continuing to operate the country’s largest dam, an Iraqi government official told ABC News. Though communications with the engineers have been difficult, the Iraqi Ministry of Water Resources is still in contact with the operating team.

The level of the water at the dam is being kept lower than normal in order to reduce the threat of a breach, even after taking into account evaporation from summer heat, officials said.

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The extremist group the Islamic State, or ISIS, released a video this week on YouTube showing its black banner flying above the dam. It wrested control of the dam away from the well-respected Kurdish Peshmerga troops last week, raising concerns among American officials.

“We are extremely concerned by this development,” State Department spokesman Michael Lavallee told ABC News at the time, “and we are coordinating with the Iraqi security forces and Kurdish Peshmerga commanders to develop options to mitigate the threat that this poses.”

Concerns remain about continued access to cement needed for the grouting process, but Iraqi government officials told ABC News that there should be three months-worth of cement stockpiles left on site.

Since ISIS took control of the dam and started closing in on Erbil, the capital of the Kurdish autonomous region where some American diplomats and military advisers are stationed, the United States military launched air strikes against the militants in support of Iraqi and Kurdish forces. The U.S. also air dropped relief aid to thousands of stranded members of the Yazidi minority who had fled ISIS persecution and sought refuge in the surrounding, arid mountains of Sinjar.

The threat posed by ISIS’ control over the dam is a severe one, according to U.S. government reports, U.S. officials and outside experts.

The Mosul Dam was constructed in the mid-1980s on what reports indicate was a terrible spot to build a two-mile-wide dam.

“Mosul Dam, the largest dam in Iraq, was constructed on a foundation of soluble soils that are continuously dissolving, resulting in the formation of cavities and voids underground that place the dam at risk for failure,” said an urgent letter sent from David Petraeus, then commanding general of the U.S. Army, and Ryan Crocker, then U.S. Ambassador to Iraq, to Iraqi Prime Minister Nouri al-Maliki in 2007.

The dam requires “extraordinary engineering measures” -- namely constant grouting operations -- to fill in the holes and “maintain the structural integrity and operating capability of the dam,” according to a U.S. Army Corps of Engineers (USACE) report from the same year.

For 30 years –- and through several periods of violent conflict -- the Iraqi government has managed to keep the dam upright by continuously pumping in literally tons of grout like an industrial version of the little Dutch boy, as a geotechnical expert who worked on the dam put it.