In April 2014, fighters of the Islamic State in Iraq and Syria captured the Nuaimiyah Dam in western Iraq, despite earlier efforts to defend the site. They then overflowed it to dislodge Iraqi soldiers dug in upstream of the site—and to deny drinking water to civilians downstream.
Iraq’s water woes do not stop with this one facility’s loss. Mosul Dam, which ISIS also now controls, is a maintenance nightmare due to shoddy construction and neglect and could collapse under the Islamists’ feet. And ISIS is targeting another dam, at Lake Haditha in western Iraq, which if breached would be a catastrophe because of its proximity to Baghdad.
Foreign Policy accurately described Iraq’s dams as its “soft underbelly.” The potential of water as a weapon of mass destruction in Iraq should come as no surprise, given the country’s dependence on its two great rivers, the Tigris and Euphrates.
Cyrus the Great reputedly took Babylon in a single night in the 6th century, B.C., by diverting an old artificial lake back into the Euphrates, so that his army could come right up to the city walls at night.
Hulagu, the destroyer of medieval Baghdad, used the Tigris River’s flood waters to trap the caliph’s horsemen outside the city walls. In the 1980s, both Iran and Iraq used water as an area denial weapon to check the other’s advance in the southern marshlands. Iran tried to bomb Iraqi dams out of commission.
Following the First Gulf War, Saddam Hussein’s regime drained the southern marshes in order to force the Marsh Arab population to give up its insurgency. For Hussein, water was also a means to cover up war crimes. The flooded areas that the unfinished Makhoul Dam would have covered conveniently included sites of the regime’s mass killings of Kurds.
Flooding the enemy’s territory—or even your own—is an old military tactic. But it rarely works, because it depends too much on terrain. There are two ways of using water to wage war on land. As an area-denial weapon. And as a siege engine for destroying food and shelter.
Blowing up a dam will flood the area below it. This could be the primary purpose of the effort—to deny the enemy use of the terrain for fortification or habitation. Alternatively, you might destroy a dam in order to knock out a hydroelectric plant or reservoir, undermining the enemy’s war economy.
The extreme, but rarest, method is to release water to redraw the map in order to teach the enemy a lesson. The Mongols destroyed the medieval city of Gurjang in Central Asia by breaching a nearby dam—making an example of those who dared resist their advance.
It’s not clear if this inspired the scene in J. R. R. Tolkein’s fantasy novel The Two Towers, in which Ent tree-creatures flood the camp of the turncoat wizard Saruman by breaching a dam.
In The Netherlands, inundation was a key defensive military strategy for centuries. After achieving independence from Spain, the Dutch developed the Hollandic Waterline, a semi-contiguous moat for Dutch forces to fortify behind in wartime. Construction began in the 17th century. The Netherlands maintained the works until the 1960s.
The Waterline didn’t give the German Wehrmacht much trouble during World War II. Later in the war, the occupying Germans broke dikes to try to halt the Allied advance. This didn’t delay the Allies much, either—but it did destroy about a quarter of the country’s total farmland ahead of a very bitter winter.
The Allies also blew up dikes in The Netherlands for tactical purposes, but not on a large scale.
The Germans also flooded terrain in Italy in order to deny it to the Allies, leading to terrible malaria outbreaks. Adolf Hitler reserved the worst for his own Reich, however. His scorched-earth Nero Decree would have destroyed German hydroelectric and flood control systems on the cusp of German defeat in 1945.
Wise German officials declined to carry out the suicidal order.
The Royal Air Force carried out the most famous dam-busting action in Europe in World War II. No. 617 Squadron—the famed Dam Busters—launched Operation Chastise against targets in the Eder and Ruhr Valleys in 1943.
The operation breached multiple dams to take power plants offline, but actually achieved very little in the long run because it was a one-off assault—and the Germans quickly repaired the damage. Still, the flooding from the breaches killed more than a thousand German civilians plus many Allied prisoners trapped in downstream camps.
In terms of sheer loss of life, one area-denial far surpassed Chastise. Hundreds of thousands of Chinese civilians died when the Nationalist Chinese breached the Yellow River dikes in June 1938.
Nationalist generals planned to “use water as a substitute for soldiers” during the Battle of Wuhan, according to Diana Lary’s War and State Terrorism. It was a hasty decision. The speed of the Japanese advance canceled humanitarian concerns.
Nationalist soldiers bombed and hacked at the dikes for days, until the first breach took place on June 9. There was no coordinated evacuation for the people in the water’s path—nor even much early warning. Most officials had already fled ahead of the Japanese army and very few households had radios or telephones.
Neither the retreating Nationalists nor the Japanese occupiers provided much relief to the survivors. And no civilian aid organizations could get into the disaster zone due to the fighting.
Owing to the flooding, the Japanese army had to give up on its immediate target, the city of Zhengzhou. But the floods failed to halt the main Japanese offensive on Wuhan. And the Nationalists mercifully declined to also flood the Yangtze River, along which Wuhan lies. The city fell in October 1938.
The Nationalist government tried to blame the disaster on the Japanese even though refugees, the military and the foreign press all knew quite well that Chinese spades and mortars were responsible.
Ironically, the disaster had less effect on morale than the Nationalists feared it would, for the same reason it isn’t very well known outside of China today. It was one tragedy among many in a region already torn apart by war and disaster.
We still don’t know the death toll of the “largest act of environmental warfare in history,” as scientist Steven Dutch dubbed it. The Nationalists estimated that around 800,000 people perished from the flooding and resulting loss of shelter, food and safe drinking water.
In time, the Communists estimated as many as 900,000 civilians died. Between three and 12 million people lost their homes. By comparison, the Chinese lost a quarter of a million soldiers in the actual Battle of Wuhan, and the Japanese around 100,000.
After World War II, the U.S. military bombed dams in North Korea and North Vietnam to destroy the communist governments’ electricity and irrigation infrastructure. This was, until the Iran-Iraq War, the final occurrence of such soggy tactics. In 1977 the Geneva Conventions specifically outlawed the targeting of water infrastructure in wartime.
That legal nicety bothers none of the warring parties in Iraq. ISIS has made clear its disregard for the laws of war. And Iraqi officials in Haditha told The New York Times that if they were in danger of losing the dam, they would open the floodgates to try and stall the anti-government forces.
Today’s water wars are more likely to involve disputes over dam locations on major rivers, since multiple countries tend to share the world’s biggest waterways. The crisis in Iraq is a reminder that water can still be an actual weapon, as well.