Europe | Après le déluge

Russia’s explosion of a huge Ukrainian dam had surprising effects

A year after the blast and flood, Ukrainians disagree over whether to rebuild Kakhovka

Early on June 6th 2023 explosives tore through the Kakhovka dam and hydroelectric power plant (HPP) in southern Ukraine. The blast shook windows 80km away and released a thundering cascade from the reservoir, which had a capacity of around 18 cubic km, almost that of the Great Salt Lake in Utah. The dam had sat astride the Dnieper river since the 1950s. Flooding devastated dozens of towns and villages. Volodymyr Zelensky, Ukraine’s president, called it “an environmental bomb of mass destruction”. Ukraine blames Russia, which had taken over the dam. Western governments and independent open-source analyses support the claim.
A year later the long-term consequences are becoming clear. They are environmental, social, political and economic. Even as fighting between Ukrainian and Russian forces rages, a debate has emerged about how to build back. The fate of the dam gives a preview of the difficult questions that will arise about the country’s reconstruction once the war is over.
The disaster directly affected four oblasts, or regions: Kherson, Mykolaiv, Dnipropetrovsk and Zaporizhia. In Kherson, downstream, the immediate toll was greatest. The province has been a crucial theatre in the war. Russia captured much of it soon after the invasion, but in November 2022 its forces were pushed back to the eastern bank of the Dnieper river, which bisects the region. After the dam’s collapse, flooding caused havoc.
Kakhovka dam
Within days the water receded, but the damage was still becoming clear. Lyubov, whose house in Kherson was flooded, says that at first the authorities took an interest in assessing the damage, but that now there is little talk of rebuilding or overhauling the ruined homes. Today on the gates of derelict houses in Kherson are the phone numbers of the owners who have abandoned them. The UN estimates that up to a million people were left without drinking water. Cities to the north of the reservoir in Dnipropetrovsk, including Kryvyi Rih and Nikopol, were badly affected. Many people still face shortages, though a new pipeline is reportedly nearly complete.
The loss of the reservoir also hurt southern Ukraine’s agriculture. The lake supplied irrigation systems in Dnipropetrovsk, Kherson and Zaporizhia, which, along with Mykolaiv, contained around 25% of Ukraine’s cultivated farmland. Dozens of wells were dug as make-shift alternatives, but many farms can only hope for rain. The loss of irrigation could reduce crop yields by 70%. Farming was already dangerous in Kherson. Retreating Russian troops sowed fields with mines. This, combined with the water problems, stopped many people from returning to the fields after the flood.
The broader environmental effects added to the devastation. The disaster is thought to have damaged nearly half a million hectares of protected land and water habitats, killing thousands of animals and birds. Water tainted by petrol, sewage and other pollutants quickly reached the Black Sea. By mid-June Ukrainian scientists said the contaminated water covered more than 7,300 square km, and was approaching the mouth of the Danube in Romania. Upstream, meanwhile, mussels and other creatures that had previously helped to filter the reservoir’s water rotted.
Mr Zelensky has described Russia’s bombing of the dam as an “ecocide”. Ukrainian investigators are collecting environmental evidence as part of a war-crimes case that they are bringing before the International Criminal Court. Yet some scientists have expressed surprise at how quickly areas have recovered. To understand this optimism, look upstream to the former reservoir.
Jun 5th 2023
10 km
Nuclear power plant
Zaporizhia
↙ Kakhovka dam (80 km)
After the dam’s collapse the former lake bed, an area of 1,870 square km, resembled a desert. Satellite imagery showed plains of compact sand and shrub divided by a narrow remaining section of the Dnieper.
Researchers had expected a thin layer of vegetation to appear by spring 2024. They predicted that these plants would be mainly invasive species, which were prevalent in samples taken from the area soon after the disaster.
Yet the speed of growth and its quality exceeded expectations. In autumn 2023 a group of scientists led by Anna Kuzemko of the Kholodny Institute of Botany found that several new habitats had formed on the lake bed.
Among the largest was willow thicket; some trees had grown to more than three metres tall. Other habitats included marshy vegetation and sandy beds.
In March 2024 parts of the reservoir flooded, probably because of melting snow, something that had occurred in the floodplain in springtime before the dam was built.
“I thought that at least for the first few months after the draining of the reservoir there would be no permanent vegetation, maybe some local vegetation, but not the permanent cover of poplars and willows,” says Bohdan Kuchenko of Ecoaction, an environmental group. The green recovery has led some to argue that the reservoir should never return. Among them is Oleg Dyakov of Rewilding Ukraine, an NGO. Before the war, his organisation identified the Dnieper delta and estuary as an area of potential for restoring long-lost wildlife. Now he believes refilling the reservoir would waste an opportunity. Within three to five years, he thinks, a “mosaic landscape” of forest, reed-beds and shallow lakes could form.
Such arguments often draw on a sense of historical injustice. To build the reservoir, Soviet engineers destroyed an area known as Velykyy Luh, or “Great Meadow”, a diverse landscape that spread across the tributaries, forests and marshes. Cossacks, totemic figures in the Ukrainian national imagination, lived off the fertile soil between the 16th and 18th centuries. A new reservoir, the theory goes, would repeat the damage that the Soviets inflicted on Ukraine’s cultural heritage.
Turning back the centuries, however, may be impossible. Some researchers note that climate change will make the region dryer. That could halt the growth of vegetation, and put more pressure on irrigation systems. Some scientists have proposed building a smaller reservoir to give more space to nature. Another idea is to construct a series of mini-reservoirs (the original Kakhovka HPP was itself in a large cascade of facilities along the Dnieper). Mr Kuchenko says that “a huge reservoir” and power plant is no longer necessary; electricity could be generated from other sustainable sources such as solar or wind.
Some in Ukraine’s energy sector are sceptical. There is “no alternative” to rebuilding the dam and reservoir, says Oleksandr Kharchenko of the Energy Industry Research Centre, a think-tank in Kyiv. He suggests that a large hydropower capacity will be important for restoring Ukraine’s energy system following Russian attacks on infrastructure, and for the transition to renewable energy.
Then there is the Zaporizhia nuclear power plant, which is under Russian occupation on the eastern bank of the river. It used the reservoir to cool its reactors, which are currently in shutdown modes. Following the dam blast the plant had to rely on an artificial lake until its staff dug wells to boost supply. Mr Kharchenko says that turning the plant on after the war would require the reservoir’s return.
Ukraine’s government has suggested that it plans to rebuild the HPP when possible. In March it issued a decree stating that the reservoir bed could not be used for any other purpose for up to five years after the end of martial law, which remains in force.
Still, two main factors complicate any reconstruction plans. The first is money. Rebuilding the HPP will cost nearly $1bn, according to the Kyiv School of Economics. The broader reconstruction costs, which cover housing, agriculture, sanitation and more, are estimated to be over $5bn. Yet these figures can only be understood in the context of Ukraine’s reconstruction costs as a whole. Those have now reached $486bn, according to the World Bank, $75bn more than its estimate in March 2023.
The scale of the task will force Ukraine and its partners to use their limited resources carefully. The construction of a vast new reservoir may have to wait. One Ukrainian hydrologist points to the Dnipro HPP, the country’s largest, which is upriver in Zaporizhia and was badly damaged by an air strike in March. Repairing that, he says, is more urgent than rebuilding Kakhovka.
The second factor is the course of the war. Any reconstruction requires the liberation of the eastern bank of the Dnieper. The front has barely budged in Kherson since the Russians left the western bank in 2022, though Russia is expected to expand its offensive in the summer. Lyubov, from Kherson, says that “only after the victory will we be able to understand for ourselves what to do next and how to rebuild our homes.” For now she is just trying to survive under enemy shelling. Upriver, the natural experiment on the reservoir bed looks set to continue.

Sources: Copernicus; Institute for the Study of War; OpenStreetMap; The Economist