The Kakhovka dam on June 6, 2023, shortly after its partial destruction
Ukrhydroenergo / Upi / Alamy
The 2023 violation of the Ukrainian dam of Kakhovka caused deadly downstream floods, threatened to disrupt the cooling system of a nuclear power plant and deprived the water region for irrigation. But an analysis almost two years later finds the most sustainable consequence can be the huge volume of contaminated sediment left in the drained tank.
“The area of the old reservoir served as a large sponge which accumulated various pollutants,” explains Oleksandra Shumilova At the Leibniz Institute of freshwater ecology and interior peaches, Germany. Exposure to these contaminants in an almost important area as Luxembourg could constitute a long-term threat to local populations and ecosystems, and could complicate debates on the opportunity to rebuild the dam at the end of the Russian-Ukraine war, she says.
On June 6, 2023, a section of the Kakhovka dam in the south of Ukraine collapsed after an explosionReleased a torrent of water from one of the largest reservoirs in the world in the lower Dnieper river and the Black Sea beyond. Ukraine and Russia have accused each other of destroying the dam, which was controlled by the Russian forces at the time.
Ukrainian Civil servants immediately planned that floods and pollutants in water would destroy ecosystems. A United Kingdom spokesperson Conflict and Environment Observatory Calls for the destruction of the dam “the most ecological harmful act of the large -scale invasion”. But the current war has made a more complete evaluation in the difficult region.
To obtain a more complete image, Shumilova and his colleagues rebuilt the flow of water and sediments after the breach using hydrological models, satellite images and data collected before the invasion of Russia. “Our goal was to give a clear scientific response: what happened on the basis of scientific evidence?” she said.
They found that the resulting flood would have transported almost a cubic kilometer of sediment to the downstream tank, a large part of which has been contaminated by toxic heavy metals and other pollutants in upstream industry and agriculture. The flood would also have picked around 7 cubic kilometers of sediment downstream from the dam, as well as oil and other chemicals of the flooded installations along the river. When he reached the Black Sea, these flood waters have formed a variegation visible in satellite images over 7,300 square kilometers of water.
Changes in the water cover after the Kakhovka dam bursting
Eosda
Although this immediate flood was harmful, the researchers found that the contamination left its own problem. They estimate that more than 99% of the sediments contaminated in the tank remained. These sediments may contain more than 83,000 tonnes of toxic heavy metals such as lead, cadmium and nickel – and they are now exposed to air for almost 2,000 square kilometers of the old tank.
This represents a health risk for local populations that still collect water in ponds formed, explains Shumilova. It can also harm plants and animals that quickly went to what was the tank bed. It could also complicate the arguments of certain Ukrainian environmental groups that the dam should not be rebuilt after the war in order to allow this formerly unequaled ecosystem to eat, she said.
Bohdan Vykhor At the World Wide Fund for Nature's Ukraine Division applies that contamination poses a problem to restore the ecosystem. But he says that other more durable alternatives to supply the region with water and electricity should be taken into account, rather than simply rebuilding the dam.
“The construction of the Kakhovka dam for the first time was a disaster for nature, the destruction of the dam was a disaster for nature, and if we rebuild, it could be another disaster for nature,” he said.
