The Kakhovka HPP, which had been under Russian control since the early days of the invasion of Ukraine, was destroyed on the night of June 6. This led to an uncontrolled release of water from the Kakhovka reservoir on the Dnipro river. The water flooded dozens of villages and towns, including Kherson. As of June 20, according to the State Emergency Service of Ukraine, three settlements remained flooded on the right bank of the Dnipro and 17 on the occupied left bank. The Russian-appointed administration of Kherson region reported 41 deaths on the left bank. On the Ukrainian-controlled right bank, according to the latest data from the authorities, 21 people died. Five people came under fire from the Russian side during the evacuation.

Two weeks later, the water has largely receded and scientists have begun to study the consequences for the environment. All data on the environmental damage described today are only hypothetical, as the hostilities prevent specialists from collecting information on the ground. In the near future, they will be able to rely only on satellite imagery, environmentalist Evgeny Simonov told Mediazona. But it is already clear that the damage is of an unprecedented scale.

Toxic sludge, animals, mines, fuel, debris

The Ukrainian Nature Conservation Group (UNCG) used satellite data to study the flooded area in southern Ukraine from 6 to 10 June. Water flooded 554.6 square kilometres (214 square miles) in Kherson region and 57.8 square kilometres (22 square miles) in Mykolaiv region. The images clearly show the polluted water being carried into the Black Sea.

For decades, the Kakhovka Reservoir, established between 1955 and 1958, has been a depository for heavy metals, oil products, and radionuclides. These pollutants were discarded by enterprises located in Zaporizhzhia, Dnipro, and Kamianske. The contamination of the water in this reservoir had been a matter of concern for environmentalists long before the war. Now, a plume, heavy with silt stirred up from the depths of the Kakhovka reservoir, remnants of washed-away settlements, and layers of soil, was swept along the river towards Romania, Bulgaria, and Turkey.

“This silt had been lying there for decades and no one was bothered by it. Already on June 6, the space imagery showed a plume—the river bed looked like a dark red stripe. With each successive day, the water became muddier and muddier. Such large-scale pollution had never happened before—within a week the wastes accumulated over 70 years had been dragged into the sea, something that previously had not been there at all. It is impossible to figure out how much polluting waste got into the environment and where exactly. This is why our aim is to understand the problem, not to quantify it,” says Vasylyuk.

With the summer heat approaching, such amounts of mud and hazardous substances can provoke algae bloom, which in turn leads to mass death of fish and marine mammals. And it makes the water unfit for bathing.

Mines and other forms of ammunition from the Russian army’s defensive lines on the Dnipro’s left bank have been swept into the sea. For instance, an anchored river mine was discovered on a beach in Odesa. According to Andrey Demchenko, a spokesperson for the Ukrainian Border Guard Service, “uncontrollable explosions” have begun to occur in the water as explosive objects detonate upon collision with other objects. These munitions may collide with sea mines, which have already “strewn Ukraine’s territorial waters.” Marine animals, such as dolphins, are suffering acoustic injuries due to these explosions. Authorities are advising coastal residents to refrain from swimming in the sea.

Local residents have discovered the remains of homes, furniture, and appliances—including sofas, wardrobes, beds, refrigerators, televisions, doors, mattresses, gas cylinders, dishes, and clothing—washed up on the beach. “The sea is turning into a rubbish dump and an animal graveyard,” noted the Ukrainian Border Guard Service. Eyewitness videos reveal the seawater near the coast to be murky, filled with rubbish and dirty foam. In Odesa, the water has taken on a greenish hue and an unpleasant odour.

One of the videos shows the bodies of two deer impaled on rocks. Environmentalists from UNCG emphasise that not only dead but also live animals, including wild species such as the European chamois, have been swept into the sea. A female deer and a dog were found alive on the coast of Odesa. The latter had managed to clamber onto a broken plank. Locals recount stories of rescuing chicks from the water.

The State Ecological Inspectorate for the Southwestern District of Ukraine has noted a significant desalination of water in the Odesa region. Specifically, in the village of Nova Dofinivka, the water’s salinity is 2.7 times below the standard level, and at Langeron beach, it’s 2.9 times lower. Evgeny Simonov, who collaborates with the Ukraine War Environmental Consequences Group (comprising international experts gathering information on the environmental impact of the war), explains that temporary desalination is a common occurrence where large rivers meet the sea. While large influxes of fresh water may indeed render certain areas of the Black Sea less saline, these areas have been replenished by the Dnipro and Pivdennyi Buh rivers for thousands of years, suggesting that the likelihood of long-term effects is minimal.

Specialists are far more alarmed by the mud, toxins, and pathogens entering the sea.

The Kakhovka HPP had stored hundreds of tonnes of fuel and lubricants, which are toxic to both animals and humans. Initially, these flowed into the Dnipro and subsequently into the Black Sea. “There were over 450 tonnes of oil in the units and transformers at the station,” Ukrhydroenergo reported. “Today, we understand that more than 150 tonnes definitely ended up in the river. As for the rest, we will only be able to determine this after we ascertain whether the transformers and turbines are destroyed or not. That’s where all the turbine and transformer lubricant was.”

“Just one litre of petroleum products can contaminate a million litres of water, and 150 tonnes will lead to numerous consequences for Ukraine’s water resources,” Eugenia Zasyadko, head of climate at the Kyiv-based organisation Ecoaction, told CNN.

“The unusually large amount of pollutants released into the sea will affect all groups of living organisms, from plankton to cetaceans,” UNCG warned. Dead shrimp and fish have already been found on the coast in the Odesa region, but the exact causes of their deaths have not yet been confirmed.

In the Kherson region, cattle burial grounds, storage facilities for toxic waste and fertilisers, pesticide-treated fields, farms, cesspools and drains, and petrol stations have been flooded. The Ukrainian service of the BBC reports that a landfill near Hola Prystan has been submerged.

“Unfortunately, we can’t just rely on social media posts about landfills. We wouldn’t want to speculate on this issue. About 15 settlements have been turned into rubbish and were swept into the sea—that’s much more than any landfill,” notes environmentalist Vasylyuk. At the same time, judging by pre-war news reports, there were quite a few problems with spontaneous landfills in the Kherson region.

Monitoring the situation on the Russian-occupied left bank is extremely difficult. The Russian-appointed authorities have been blocking access to towns, including Oleshky and Hola Pristan. These are located in a flat floodplain, and the situation there is particularly difficult. Volunteers are not allowed through roadblocks, and even the locals’ boats have been confiscated. Vladimir Putin ordered the launch of a government commission to deal with the consequences of the flooding only on the fourth day of the disaster, and on June 13 he called the environmental consequences of the HPP destruction “solvable.”

Information about the aftermath chiefly comes from volunteers and relatives of the victims. “Now the costs of medicine are gigantic. People have been taken off the roofs, but now they have to be fed, given water, and disinfected. The residents had cowsheds, and the military had minefields there. That is, mines are floating there along with the corpses of cows and dogs,” volunteers describe the flood in Oleshky in a conversation with Mediazona.

“Most of the living organisms that inhabited the Kakhovka reservoir have already perished.”

The UNCG ecologists’ report categorises the environmental impact of the Kakhovka dam’s destruction into two areas: the damage from the reservoir’s drainage and the damage from the flooding of the Dnipro river’s downstream areas.

The Kakhovka reservoir, situated in the Zaporizhzhia, Dnipropetrovsk, and Kherson regions, was Ukraine’s second-largest in terms of area and the largest in terms of water volume. As of June 10, the Ministry of Natural Resources reported that 62% of the water from the reservoir had drained away. In the areas that have become shallow, an ancient cemetery and debris from an S-300 missile that fell a few months ago have already been discovered.

OSINT analysts from the WarMapper Twitter account posted satellite images from Sentinel-2, dated June 20, showing that the Kakhovka reservoir has almost entirely dried up within two weeks. “Only the Dnipro river itself, several tributaries, and a few small lakes in this area remain,” the researchers emphasise.

The images reveal that Tavan Island, which was submerged in the 1930s during the construction of the Dnipro hydropower cascade, has resurfaced.

The reservoir was home to at least 43 species of fish, 20 of which were commercially significant, with annual catches of up to 2,600 tonnes. According to UNCG, it could take up to ten years to restore the fish stocks, as the habitat and all spawning grounds have been destroyed. The regional administration reported a pestilence due to the rapid drop in water levels in the stock—authorities warned that eating the dead fish was dangerous due to the risk of botulism. They urged residents to drink only bottled water, as the Dnipro contains toxic substances and infectious agents—from the same cemeteries and burial grounds washed away by water flows.

“Spawning takes place in late spring and early summer, at this time there are special prohibitions—‘radio silence’ in the waters, when, among other things, it is not allowed to fish and travel by motorboat. But due to the rapid draining of the Kakhovka reservoir, almost all young fish are doomed to die,” says the UNCG report.

“Given the data on fish mortality, we can conclude that the vast majority of the living organisms inhabiting the Kakhovka reservoir have already perished,” the ecologists continue. These are crustaceans, invertebrates, and insects; the latter were a food source for fish, birds, and amphibians. In addition, some freshwater fish from the reservoir may have been swept out to sea.

Bird nesting sites and entire populations of rare animal and plant species destroyed

The rapid rise of water left no chance of survival for most terrestrial animals: mammals, reptiles, and insects. “We can confidently say that the scale of this catastrophe is incomparable with any previous events in Ukraine. Over the past 90 years, the Dnipro floodplain has been regulated by six dams and populated by species that have no effective mechanisms for escape from flooding,” explains UNCG.

According to ecologist Vladyslav Balinskyy, the dam breach led to “hundreds of islands, areas of unique floodplain forest, flood meadows, and steppe areas of the lower slopes with all their inhabitants being washed into the sea.”

According to UNCG, the flood could have killed up to 70% of the population of the already endangered Nordmann’s birch mouse (Southern vole), the populations of sand voles (endemic to southern Ukraine), and the Falzfein’s thick-tailed three-toed jerboa could have been halved.

The draining of the reservoir and the flood affected tens of thousands of birds, including herons, glossy ibises, terns, coots, moorhens, mute swans, during the nesting period when some had already hatched. The recovery of the numbers of dead birds of prey, such as marsh harriers, may take up to ten years.

The flood affected rare ants and reptiles—Red Book-listed Vipera ursinii and Caspian whipsnake. The sand and the steppe-runner lizards could also have been affected. Pollutants entering the river will also negatively impact amphibians, which are sensitive to water quality.

Due to the draining of the Kakhovka reservoir, local aquatic and floodplain plants are likely to disappear, and the dried-out area will be filled with dangerous weeds.

One of the unobvious consequences of the destruction of the Kakhovka HPP is the rise of the groundwater level in the national park “Oleshky Sands” on the left bank of the Dnipro: “Water is already soaking tree roots and destroying animals in their burrows.” The fate of the endemic Dnipro birch is also alarming; the populations of wild orchids from the Red Book of Ukraine, according to scientists, are also under threat of destruction.

Due to flooding and rising groundwater, 47 protected natural areas on both banks of the Dnipro may be partially or completely affected, including the national parks “Beloberezhie Svyatoslav” and “Lower Dnipro,” the Black Sea Biosphere Reserve and the “Emerald Network.” According to UNCG calculations, the draining of the Kakhovka reservoir will affect at least 11 protected natural areas, including the national parks “Kamenska Sich” and “Velykyi Luh.”

Contaminated drinking wells, risk of cholera and other infections

The bodies of domestic animals and livestock in hot weather will contaminate water and soil, which could lead to the spread of infectious and viral diseases, according to representatives of the Civil Environmental Movement of Ukraine.

In the 1950s and 1970s, livestock infected with anthrax were buried between the villages of Dnepriany and Korsunka, which are located on the left bank of the Dnipro. Now these cattle burial grounds have gone underwater. “That area was definitely infected. There was constant monitoring there before, soil samples were taken, but they dug shallow. Now the water can wash everything away. This means that anthrax spores can get into the Dnipro and the Black Sea,” ecologist Taisiya Kozak told the BBC Ukrainian Service. She heads the environmental organization “Mama-86” in Nova Kakhovka.

“If the [anthrax] spores, washed away by water, will slowly go out to sea, the risk is low. If there are violations, if this water is used to water animals, the forecast will be different,” noted the head of the Ukrainian Ministry of Health, Viktor Lyashko, in a conversation with journalists.

About 700,000 people have been left without access to drinking water due to the dam’s destruction. Currently, 90 observer teams are taking samples in the Kherson and Mykolaiv regions and have already identified anomalies: in the Inhulets river, they have recorded significant exceedances of permissible concentrations of suspended substances. The levels of ammonium nitrogen, nitrites, chlorides, and iron have also drastically increased, all of which indicate that wastewater has entered the river.

The contamination of water in drinking wells, which now need to be disinfected, could lead to the spread of hepatitis A, salmonellosis, shigellosis, and acute intestinal infections. According to Igor Kuzin, Ukraine’s Chief Sanitary Doctor, there is a risk of a cholera outbreak due to the mixing of sewage water with drinking water.

“The southern regions of Ukraine have always been considered potentially favorable for the spread of acute intestinal infections and cholera due to the warm, humid climate and high groundwater level. However, the risk of disease has now increased hundreds of times,” emphasized the state tourism agency.

Chief Sanitary Inspector Kuzin claims that the epidemic situation in the Ukrainian-controlled territories is “predictable and manageable.” He states that anti-epidemic and chemical surveillance teams monitor water conditions daily: “38 monitoring points have been established in the Odessa, Mykolaiv, and Kherson regions.”

Since June 19, swimming and fishing have been prohibited in these regions due to the deterioration of river and seawater indicators. In the sea near Odessa, positive results for RNA of rotavirus A and DNA of salmonella have been detected, while concentrations of suspended solids and iron have exceeded permissible levels at the local Langeron beach.

“Fields in the south of Ukraine could turn into a desert as early as next year”

Another consequence of the hydropower plant’s destruction is the inability to supply water for irrigation to the fields in the southern part of the Kherson region, where grain is cultivated.

The bottom sediments of the Kakhovka reservoir, which have accumulated harmful substances, will eventually dry out, and the toxic fine dust will be carried by the wind over large distances. According to the Civil Environmental Movement of Ukraine, this will impact not only human health but also crop yields.

Fertile layers of soil will be lost due to flooding, and the rise in groundwater levels will not only increase the land’s moisture but also lead to its salinization.

“In settlements that have not been flooded, the groundwater level has risen so much that houses are simply sinking into the ground. We don’t see this on satellite images, but we hear about it from local residents,” says Vasylyuk.

The Kakhovka reservoir used to provide irrigation to the Dnipropetrovsk, Kherson, and Zaporizhzhia regions. The Ministry of Agricultural Policy and Food predicts that “next year, fields in the south of Ukraine may turn into a desert.” According to the ministry, up to 10,000 hectares of agricultural land on the right bank have been flooded, while on the low left bank, which is occupied by Russia, the extent of flooding may be several times larger, with part of the territory likely to remain underwater.

Editor: Yegor Skovoroda

Translator: Daria Fomina