It was a sultry-hot Sunday in August 2014 when ISIS came to the Iraqi town of Snune. Roaring around the flanks of Sinjar Mountain in the country’s far northwest, the black-clad fighters quickly seized whatever men, women and children hadn’t been able make their escape after Iraqi and nearby Kurdish forces collapsed when faced with the ISIS surge. The men and old women were mostly murdered and dumped in mass graves; the others were sold into slavery.

Then, having eviscerated the area’s human life, the jihadists got to work on the natural landscape. First, they carted away anything of value, including many miles of electricity line and tens of thousands of livestock. Soon after, they torched much of what couldn’t be filched. The shattered villages are still littered with the blackened stumps of once-sprawling olive groves. Finally, as a kind of primeval coup-de-grace, they poisoned or sabotaged practically every well they could get their blood-stained hands on before slowly falling back as the anti-extremist coalition regrouped.

In Sheikh Romi village, just to Snune’s east, ISIS choked at least one well with oil, and jammed up several more with ragged metal debris. In the villages to the south of the mountain, the group clogged scores of wells with rocks and rubble. In doing so, it reduced a lush agricultural district to a parched wasteland of swirling dust and bare fields. By the time the extremists had had their fill of looting and destruction, there was scarcely a functioning water outlet left. The message, residents say, was unequivocal: “Even if you survive us, you won’t survive the lifeless environment you’ll return to.”

Since the dawn of conflict, armed groups have targeted water as both a tactic and potential weapon of war. In savaging rivers, wells, lakes and more, attacking troops punish locals for their lack of support—or render the land useless if facing imminent defeat. And by harnessing these resources, groups can alternately flood or starve opponents of water, historically a ploy favored by those up against unkind odds. Time and again, the Dutch burst dikes to keep foreign armies from advancing across their otherwise mostly indefensible land in the 16th, 17th, and 18th centuries. No matter how much human society might evolve, some things—notably civilian suffering in conflict—never seem to change.

ISIS is a case in point. Their acts have sometimes been presented as a kind of unique evil, a bloodthirsty wave of butchery and beheading. But while the jihadists appear to bask in their atrocities more than most, they are in some ways simply dining off an extensive canon of past horrors. In an era of increasing water scarcity, experts suggest there’s every chance that we’ll soon add to it.

“The fundamental value of water to life makes it an attractive target during conflict,” says Peter Gleick, a scientist and water expert at the California-based Pacific Institute, which charts water-related violence. “We understand now that that is a violation of human rights, but that has not prevented it, even in modern times, from being casualty of war.”

Beginning perhaps with the ancient dispute between the cities of Lagash and Umma, coincidentally in modern-day southern Iraq, water-related conflicts appear to have been a fixture of early warfare (though a lack of documentation can make it near impossible to verify reports). According to surviving engravings in the Louvre, these Sumerian states came to blows around 2450 B.C. over water rights and control of a prime patch of agricultural land, with Lagash ultimately triumphing after piercing their enemy’s lines in battle. Over the course of the fighting, Eannatum, the king of Lagash, was said to have cut off access to some canals and dried out others, thereby condemning arid Umma to a punishing thirst. It was a brief taste of the misery to come.

"I, Eannatum the powerful, called by Ningirsu [the Lagash god], to the [enemy] country, with anger, that which was in all times I proclaim!” reads one of the surviving fragments of the Stele of the Vultures, a limestone slab on which Lagash documented its victory in cuneiform script. “The prince of Umma, each time when with his troops he eats the Gu-edina, the well-beloved lands of Ningirsu, may the [latter] lay him low."

That strategy was seemingly perfected by the Assyrians, who roamed much of the same turf that ISIS would later seize in northern Iraq and Syria. King Assurbanipal (668 B.C. - 627 B.C.) is said to have dried out the wells of besieged Tyre, having previously dispatched guards to keep his defeated foes away from wells in a previous conflict. “By sea and dry land, I took control of (all of) his routes,” Assurbanipal’s scribes wrote of the King of Tyre. “I constricted (and) cut short their lives.” Again, some historians question the evidence, suggesting that Assyrian forces might have simply drained wells as they looked to quench their thirst. It’s no coincidence, though, that many of these accounts continue to surface in water-scarce parts of the world, like the Middle East, where the destruction or seizure of wells and other water resources can be deployed to most devastating effect.

Over the following millennium and a bit, as records improved, the reports of well poisonings came much thicker and faster. The 12th-century Holy Roman Emperor Frederick Barbarossa is said to have dumped human corpses down wells while on a campaign of conquest in Italy in 1155, an early form of biological warfare. Saladin, the great Saracen commander, deprived the Crusader armies of access to water in the Holy Land in 1187, contributing to their defeat at Hattin. He supposedly later blocked up local Christians’ wells with sand as punishment for aiding his enemies. In the Balkans, where the Ottomans were looking to incorporate new territories into their empire, both imperial troops and local rebels, like Vlad the Impaler, the inspiration for Dracula, are said to have sabotaged water resources.

However, perhaps the most notorious allegations of well poisoning involved no well poisoning at all. Across medieval Europe, Jews and other minority groups were frequently accused of poisoning water sources at a time when water-borne and other diseases were exacting heavier tolls. Thousands were dying in then-inexplicable circumstances, particularly in some unsanitary and fast-growing cities like Prague and Wroclaw (formerly known as Breslau) in Poland, and people needed a scapegoat. When catastrophe struck in 1348 accusations surged. “During the Black Death, the bubonic plague killed many, and some people interpreted this as a sign of mass poisoning,” says Tzafrir Barzilay, a historian of medieval European society at the Hebrew University of Jerusalem.

In several instances, lepers in France and Belgium were accused of poisoning springs and streams in the early 14th century and burnt alive – after “they were corrupted by the Jews,” according to a monastery source. Regulations were introduced in a number of places like Vienna banning Jews from consuming food and drink meant for Christians for fear of poisoning. It wasn’t until the mid-15th century that the furor began to abate.

By the 20th century, reports of well poisonings appear to have slowed, at least in Europe. New weaponry had shortened many conflicts, while some notions of professional military conduct had taken hold. Well-poisoning opportunities had also diminished as industrializing societies moved away from small-scale borehole use. But the nastier the war, the more the likely the deployment of scorched-earth tactics, and the First World War soon punctured any sense of advancement. In early 1917, the German army withdrew 25 miles (40 kilometers) to a shorter, more defensible line in northern France, a maneuver known as Operation Alberich. With fighting on the Eastern Front absorbing much of his army, the Kaiser sought to minimize the impact on his outnumbered divisions in the West. But he also wanted to make sure this lost land, a greater gain than the Allies had managed in two-and-a-half years of war, could be of no material advantage to his opponents. As they retreated, the Germans soiled wells, excavated roads, downed trees and planted land mines.

In 1942, the Nazis army continued the practice as their Reich began to weaken for the first time. Emboldened Greek resistance fighters upped attacks from their mountain hideouts. German troops responded with relentless anti-guerilla operations. Very soon, central and northern Greece “was turned into a dead zone of ruined property and rotting harvests,” writes Mark Mazower in Inside Hitler’s Greece: The Experience of Occupation, 1941-44. “Most peasants were afraid to approach their fields lest they be killed; in some cases, villagers were actually forbidden by the Germans to sow or reap their crops.” During the last stages of the Axis withdrawal, a number of villages, including Agios Georgios near Karpenisi, were completely flattened, their wells fouled with the corpses of dead mules.

In the Pacific theater, meanwhile, Japanese scientists infected thousands of Chinese wells with cholera in the late 1930s and early 1940s to test the effects on villagers. “Military and civilian medical personnel conducted experiments on human subjects without their consent that rivaled and, at times, exceeded those of the most inhumane Nazi doctors,” writes Sheldon H. Harris, author of Factories of Death: Japanese Biological Warfare, 1932- 45 and the American cover-up. Many of the key participants in the program later escaped justice after striking deals with a U.S military keen to learn from their research.

In recent decades, ISIS have provided the best-known instances of the use of water in war. In addition to poisoning wells, they used their captured dams to drown and then deprive thousands of downstream farmers of water. But they’ve had plenty of company. Saddam Hussein targeted wells in Kurdistan, including a large one north of Halabja during his infamous airborne chemical attack on the town in 1988. Water experts are still trying to repair the damage decades later. From fatal disputes over access to well water in drought-ridden Somalia to fierce water-related skirmishes between herders in arid Mali, there have been myriad examples in the past few years alone. Relying on groundwater for drinking isn’t solely a developing world challenge; though the figure has shrunk in recent decades, over a third of Americans still rely on groundwater for drinking, including more than 40 million who extract from private wells.

As climate change saps rainfall in places and population growth and state mismanagement deplete groundwater in others, hydrologists anticipate more well destruction in the years to come. “We’re doing an analysis of the data now in the conflict chronology, and even setting aside questions of the quality of data over time there are very clear trends of increasing attacks on water sites, increasing use of water as a weapon, and I think that reflects growing pressure on water worldwide,” says Gleick. “Water is becoming increasing valuable, increasingly scarce, and unfortunately increasingly fought over. And I don’t see it going the other way.”