“Forget scorched earth campaigns. Some of history’s armies have tried to soak their enemies using man-made floods.”

UNABLE TO BEST their Spanish opponents in open battle during the Eighty Years War, Dutch rebels hatched a creative (if not foolhardy) plan to drive off the occupying Catholic armies once and for all.

Beginning in 1584, William of Orange ordered his men to open a series of gaps in the network of levies and dykes that kept the low-lying lands of the south-western Netherlands free from flooding.

While submerging much of the landscape in seawater certainly denied the Spaniards a foothold, according to one researcher, the collateral damage was unbearable.

“The plan got completely out of hand,” said Adriaan de Kraker a historical geographer with VU University in Amsterdam. “It came at the expense of the countryside of Zeeland Flanders, some two thirds of which was flooded.”

Research published this week in the journal Hydrology and Earth System Sciences reveals that the flooding left vast areas of the Netherlands virtually uninhabitable for generations, while salt from seawater rendered the region’s farmland largely unusable for a century.

Interestingly enough, this is not the only case of armies ‘weaponizing’ water in time of war. A number of military powers throughout history have dabbled in ‘strategic flooding’ in an attempt to wash the enemy from the battlefield. Here are some other examples of ‘soaked earth’ campaigns.

The Battle of the Yser

The Belgian military unleashed a wall of water against the mighty German army in the desperate early days of the First World War. With the Kaiser’s troops marching towards the Yser River in West Flanders in October of 1914, allied commanders ordered the Nieuwpoort canal locks opened. The resulting surge spread across a 10-mile swath of countryside, transforming the enemy lines into a veritable lake and threatening to drown thousands of German troops in their trenches. The flooding succeeded in halting the enemy advance, but it devastated the landscape. “Picture to yourself a bare, sinister plain,” reported one eyewitness to the calamity. “Here and there the inundations have produced great sheets of water, whence emerge the ruins of farmhouses, and on which all sorts of rubbish is floating, and often corpses.”

The Yellow River Catastrophe

Chinese nationalists used flooding on an even more massive scale in their war against the Japanese in 1938. With enemy armies sweeping down from Manchuria into the heart of their homeland, Kuomintang leader Chiang Kai-shek ordered his troops to unstop a series of dykes along the Yellow River unleashing a massive water surge that engulfed Henan, Anhui, and Jiangsu provinces — an area roughly equal to the size of California. In what has since been described as the worst man-made environmental disaster in history, as many as 1 million Chinese civilians drowned in the torrent while more than 12 million were displaced. Although the flood stemmed the Japanese advance into the central Chinese heartland, the invaders themselves were not directly affected by the rising waters – their battalions were still many miles away from the area of devastation. Worse, the strategy served to enrage local peasants who inhabited the engulfed lands, driving many into the arms of the rival communist movement.

Saddam vs. the Marsh Arabs

Who needs nuclear or chemical weapons when you can turn an entire river system into a weapon of mass destruction? That’s what Saddam Hussein proved in 1993 when he diverted the Tigris and Euphrates away from a vast wetland in Southern Iraq known as the Mesopotamian Marshes. The Iraqi dictator ordered military engineers to drain the ancient habitat in order to deny Shia insurgents sanctuary there.

The campaign, which was roundly condemned by the international community, is estimated to have turned 100,000 inhabitants of the region into refugees and rendered more than half of the once lush 20,000 sq. km (7,700 sq. mi) Arabian bayou into an arid dustbowl. In turn, the diverted rivers flooded vast areas of agricultural land further straining Iraq’s already beleaguered post-Gulf War food supply.

Tsunami Attack

The United States considered using the ocean itself as a weapon in its war against Japan. The plan, dubbed Project Seal, involved using enormous ocean-floor explosions to create massive and destructive tsunamis large enough to destroy Japanese coastal cities and port facilities. With the cooperation of the government of New Zealand, American researchers detonated more than 3,000 charges in the waters off Auckland and the nearby island of New Caledonia in order to test the idea. Experts believed that 10 massive charges totalling two million pounds of high explosives each strung out across the seabed five miles off the southern shore of Japan could produce a 33-foot swell. By comparison, the tsunami that killed a quarter million people around the rim of the Indian Ocean in 2004 was as high as 100 feet in places, while the wave that devastated Japan following the 2011 earthquake was estimated to be more than 130-feet tall. The plan was abandoned in early 1945, as the American atomic bomb project neared its completion.

The Dam Busters

Perhaps one of the RAF’s most famous operations of the Second World War involved the breeching of dams: Operation Chastise. On the night of May 16, 1943, 19 Avro Lancasters of 617 Squadron flying at treetop level struck a pair of hydro-electric dams on the Ruhr River using top-secret “Upkeep” bouncing bombs.

The 9,200-pound weapons were designed to skip along the surface of the water before striking home. Both the Möhne and Edersee dams were destroyed in the daring mission. The now-famous raids knocked out power to the river valley, briefly disrupted German wartime production and caused widespread flooding. Tragically, the surging waters swept away more than 1,500 people — a number that included an estimated 1,000 POWs and forced labourers held in the area by the Nazis. After the raid, 617 Squadron became known as the “Dam Busters.”

Postscript – The Netherlands Underwater

Just like in the 16th Century, the Dutch people bore witness to even more strategic flooding, this time in World War Two. VU researcher Adriaan de Kraker explains.

“Strategic flooding during the Second World War undertaken by the Germans remained purely defensive, while the Allied flooding of the former island of Walcheren in the southwest of the country sped up the Allied offensive,” he says.

According to the research, as many as a third of the floods to hit the southern Netherlands since 1500 were caused by armies in wartime.