Viewed from afar, the two-mile-long Mosul Dam is an impressive sight on the flat, sunbaked northern plains.

Move closer, though, and its appearance has a menacing air. The bullet-riddled causeway and abandoned guard posts tell of the dam’s seizure by Islamic State terrorists in early August, and the bomb craters and flattened armored vehicles are evidence of its recapture by Kurdish fighters 12 days later.

The sorry state of Iraq’s biggest dam, about 31 miles (50 kilometers) northwest of Mosul city on the Tigris River, shows how water has become another weapon in the terror group’s arsenal. But its steadily retreating reservoir tells another story, one of how Iraq’s water shortage is growing more urgent by the day.

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