Broken dams: deadly precedents, including in France

The dam of the Kachevskaya hydroelectric power station, located in the Russian-occupied region of Kherson region (southern Ukraine), was partially destroyed on Tuesday. Moscow and Kyiv accuse each other of damaging the work of art while saving a reservoir of more than 18 billion m3.

The International Commission on Large Dams currently lists over 55,000 large structures, i.e. structures between 5 and 15 meters high, holding over 3 million cubic meters of water. Accidents have occurred over the centuries during construction, flooding or later. Most of them did not lead to human casualties, the population, as a rule, was evacuated before the tragedy. Other breaks, on the other hand, are completely voluntary, especially during times of war. The stakes are such that the dams are protected by the Geneva Convention. Updated information on the most significant cases.

Most Devastating: Banqiao in China. In August 1975, Typhoon Nina hit the Henan province. In just six hours, 83 cm of rain fell. The first dam sags and, by a domino effect, leads to a rupture of 61 others. The loss of life only became known in 2005: the provincial hydrology department estimated that 85,600 people died during the flood, to which should be added 145,000 victims who subsequently died from famine and epidemics. The dam was reconstructed in 1986.

Other deadly precedents. On May 31, 1889, an artificial dam in South Fork, Pennsylvania (USA) broke at a height. A huge wave breaks into the valley, to the town of Jonestown, located 23 km downstream, and covers it with 18 meters of water depth. 2209 people died.

In 1963 in Italy, construction defects and successive landslides caused the Vaiont Dam in the Italian Alps to burst. The emptying of the lake is decided to reduce the pressure. On October 8, an order was issued for the partial evacuation of the population. The next day, October 9, the slope of Mount Tok collapsed, carrying millions of cubic meters of stone and earth into the reservoir. Three successive waves hit populated areas, killing 2,600 people.

On August 11, 1979, the failure of the Macchu-2 dam in India, due to bad weather, caused a wave with a height of 5 to 10 m in the city of Morvi, 5 km downstream. The number of victims is estimated at 2,000 to 15,000.

There are two fatal accidents in France. In April 1895, 87 people died as a result of the breach of the Buzet (Vosges) dam. Cracks appeared on the structure, which began to deform before suddenly giving way. The study of the accident subsequently made it possible to change some design data. On December 2, 1959, the Malpasset (Var) dam, built five years earlier, broke during the first filling. Two weeks of heavy rains caused the water level to rise and part of the foundation to creak. 50 million cubic meters of water and mud swept the city of Frejus. The damage was significant: 423 dead, including 135 children, 155 buildings, 1,000 hectares of damaged agricultural land. The invoice amount is two billion francs, which today is equivalent to 4 billion euros.

Rare sabotage. In 1943, the Royal Air Force (RAF) developed an aerial bombardment operation against German roadblocks in the Ruhr area. This is Operation Retaliation. On May 17, the concrete dam of the Möhne River failed, the concrete dam of the Eder River and the Sope earth dam were simply damaged. 330 million m3 of water runoff, flooding of roads, factories, railways, mines, residential buildings up to 80 km downstream of the dams. The death toll is estimated at 1,294, including 749 French and Ukrainian prisoners of war. Also killed were 53 of the 133 RAF aircraft crew. In order to prepare for Operation Retaliation and develop suitable explosives, the Nant-y-Gro Dam in Wales was destroyed without any casualties.

More recently, in 1993, at the height of the Croatian war, retreating Serb forces attempted to undermine Brana Peruc’s restraint. UN peacekeepers had been there since last summer and discovered that Serb militias had planted 35 tons of explosives at the dam, set up in such a way as to prevent disposal. Before leaving, on January 28, 1993, the Serbs blew up 5 tons of explosives in the foundations. But, as we learn two years later, the UN observer, Briton Mark Nicholas Gray, lowered the water level in the reservoir until the dam collapsed. Without his intervention, 20,000 people could have died.

There is a double historical precedent in Ukraine. After the destruction of the Kachevskaya dam, Kyiv quickly blamed Moscow for this. And in fact. In 1941, Ukraine was invaded by Nazi Germany and was subjected to a very tough occupation regime. Soviet troops multiply the destruction, and in particular, on August 18, 1941, the hydroelectric power station and the dam of the Dnieper, christened DneproGES, 170 km from Kachovka. Many villages were washed away in the floods around Zaporizhia, resulting in the deaths of between 20,000 and 100,000 people, civilians and soldiers. During the fierce battle for the Dnieper in 1943, one of the most important conflicts in the world, German troops in turn blew up the power plant, damaging the dam.