National Interest reports: A lethal threat sits in Iraq right now, one that could kill hundreds of thousands of civilians with little notice. The weapon briefly fell into the jihadis’ hands last summer, and still poses a destructive risk to much of the country.

The 750-megawatt Mosul Dam is the country’s largest, and one of the most productive in the Middle East. But its proximity to Mosul, ISIS’s biggest Iraqi city, has caused nightmares in both Baghdad and Washington.

Built during the Saddam era on a weak foundation of gypsum, the dam requires continuous maintenance and reinforcement with fresh concrete. Without these efforts, some ten billion tons of water threaten to sweep down the Tigris, flooding towns and villages hundreds of miles downriver. Baghdad could see flooding of more than fifteen feet, according to one report. A U.S. Army Corps of Engineers study in 2006 called it “the most dangerous dam in the world” and estimates of the potential civilian death toll reach as many as half a million. [Continue reading…]