The Kakhovka Dam was breached in the early hours of 6 June 2023, causing extensive flooding along the lower Dnieper river, also called the Dnipro, in Kherson Oblast. The dam was under the control of the Russian military, which had seized it in the early days of the Russian invasion of Ukraine. Many experts concluded that Russian forces likely blew up a segment of the dam to hinder the planned Ukrainian counter-offensive, and Ukraine specifically blamed Russia's 205th Separate Guards Motor Rifle Brigade. Russian authorities have denied the accusations.
The dam was about 30 m (98 ft) tall and 3.2 km (2 mi) long; the breached segment was about 85 m (279 ft) long. Two days after the breach, the average level of flooding in the Kherson Oblast was 5.61 m (18.4 ft), according to local officials.
There were signs of an explosion at the time of the breach. Both Ukrainian and Russian sources reported hearing blasts from the dam's hydroelectric power station, regional seismometers detected explosions in the area, and a satellite detected the infrared heat signature of an explosion.
Water levels in the Kakhovka Reservoir, controlled by Russia, had been rising for months and were at a 30-year high when the dam failed. Thousands of residents downstream were evacuated, and floods submerged several villages in Ukrainian- and Russian-controlled areas. By 21 June, 58 people were reported to have been killed and 31 were missing. Russian authorities officially report that 59 people drowned in total, but local health workers and a volunteer grave digger from Oleshky have told the Associated Press that the death toll was in the hundreds from that city alone, with shallow mass graves dug for the victims. According to the informants, reporting of deaths in Oleshky was hampered by interference from police beginning June 12, by relocation of bodies and by extortion of families of survivors and coercion of health care workers to misreport causes of death on death certificates, which could not be written in Ukrainian language in Russian-occupied territory or conveyed to Ukrainian authorities. Flooding killed many animals and damaged farmland, homes, businesses, and infrastructure. The loss of water from the reservoir could threaten the long-term water supply to Russian-controlled Crimea and the Zaporizhzhia Nuclear Power Plant, but there was no immediate risk to either.
Background
The Kakhovka Dam raised the natural level of the Dnieper River by 16 m (52 ft), flooding the Great Meadow and creating the Kakhovka Reservoir. This was the second-largest reservoir in Ukraine by area (2,155 km2 [832 sq mi]) and the largest by water volume (18.19 km3 [4.36 cu mi]).
Another dam on the Dnieper was breached twice during World War II in Ukraine. In August 1941, the Soviet NKVD blew up the Dnieper dam to hinder the Nazi German advance, killing between 3,000 and 100,000 Soviet civilians, as well as Soviet troops. In 1943, it was blown up again, this time by retreating German troops.
The Kakhovka dam was built in 1956 and was seized by Russian forces in February 2022, during the early days of the Russian invasion of Ukraine. Russia attacked Ukrainian infrastructure that year, damaging several other dams and leaving Ukrainians without access to water. Examples include rocket attack against Kyiv dam on 26 February 2022, the destruction of the Oskil Dam by Russian land forces in July and the missile attack on the Kryvyi Rih dam that September.
According to Ukrainian military intelligence, Russian forces carried out "major mining" of the Kakhovka dam shortly after taking control in February 2022, and in April 2022 mined locks and supports and installed "tented trucks with explosives [on] the dam itself". In October 2022, the Foreign Minister of Moldova, Nicu Popescu, said that Ukraine had intercepted Russian missiles targeting a different dam, on the Dniester river. At the time, Ukrainian president Zelenskyy warned of Russian preparations to destroy the Kakhovka dam and blame Ukraine, and called for an international observation mission at the dam to prevent a potential catastrophe.
On 19 October 2022, the Institute for the Study of War (ISW) reported that Russia was likely setting information conditions to conduct a false-flag attack on the Kakhovka Dam. The Russian military announced that they had received information that Ukraine intended to strike the dam. According to ISW analysis, they likely intended these warnings to set information conditions for Russian forces to damage the dam and then to blame Ukraine, while using the floods to cover their own retreat.
In late 2022, Ukraine retook the western bank of the Dnieper during the Kherson counteroffensive. Ukraine accused Russia of planning to breach the Kakhovka dam with explosives in retaliation. During the counteroffensive, Ukrainian Major General Andriy Kovalchuk at one point considered flooding the Dnieper River below the dam, so Ukrainian forces conducted HIMARS test strikes on the Kakhovka dam. One strike targeted one of the dam's floodgates to determine if the rocket could open it. The test was deemed a success and the action was kept as a "last resort" in case of a Russian offensive.
When Russian forces retreated from Kherson in November 2022 they destroyed the bridge deck behind them, damaging some of the sluice gates in a controlled demolition.
The Russians then opened more sluice gates, allowing water to rush out of the reservoir. Ukraine's Zaporizhzhia Regional Military Administration suggested that Russia intended to flood the area south of the dam, to keep Ukrainian forces from crossing the Dnieper River. Ukrhydroenergo, Ukraine's hydro electric company, likewise believed Russian occupiers "opened the station's locks fearing an advance of Ukrainian soldiers". Spring 2023 brought an unusually large amount of rain, with 3.5 times the normal amount of rainfall recorded in April.
On 3–6 May, satellite photos indicated that Russian forces were building a small dam on Tokmachka river, which caused flooding upstream in the path of an expected Ukrainian offensive. Some called this part of a Russian pattern of using flooding to thwart the Ukrainian counteroffensive.
From mid-February to late May 2023, either deliberately or as a result of neglect, the damaged dam was not adjusted to match the increased water flow. As a result, water washed over the top of the dam and land upstream of the dam was flooded. Water levels in the reservoir reached a 30-year high. According to journalist Peter Beaumont, it is possible that Russia had deliberately allowed water levels to rise to an extraordinary level in order to make the collapse more impactful.
A small part of a wall separating the dam and the power plant collapsed on 23 April (44 days before the dam failed).
On 28 May an aerial photo was taken of a car that appeared to be loaded with explosives, in the form of large barrels and a land mine, parked on the top of the dam. According to a Ukrainian special forces communications official, the purpose of the car was both to stop any Ukrainian attack on the dam and to amplify the explosion that the Russians planned to originate in the machine room, which was located in a building to one side of the dam. Early drone footage suggests that the initial dam destruction occurred near the machine room.
On 30 May 2023, less than a week before the dam breach, the Russian government decreed that in occupied Ukraine, "Until 1 January 2028, technical investigations shall not be carried out into accidents at hazardous production facilities and accidents at hydraulic structures that occurred as a result of military operations, sabotage and acts of terrorism." Oleg Ustenko, an economic adviser to Ukrainian President Volodymyr Zelenskyy, called this a "smoking gun", saying that it would take somebody with a "very vivid imagination" to believe that the passing of this legislation less than a week prior to the destruction of the Kakhovka hydroelectric power station, covering precisely the circumstances that would transpire, was just a coincidence.
On 2 June, a small part of the road over the dam collapsed, along with parts of the piers which supported them, according to satellite images obtained by BBC News. According to NPR science correspondent Geoff Brumfiel, "That indicates to me that there were structural issues at the facility before whatever happened today."
The Institute for the Study of War reported on June 6, the day the dam was destroyed, that "Russian sources have expressed intense and explicit concern over the possibility that Ukraine has been preparing to cross the river and counterattack into east bank Kherson Oblast."
Destruction
Between 2:18 and 2:20 a.m. local time on 6 June 2023, Ukrainian and Russian sources reported loud sounds like explosions that appeared to come from the Kakhovka Hydroelectric Power Plant in the dam. Nova Kakhovka residents discussed the explosions on a Telegram channel with 5,000 members, with one resident describing (in Ukrainian) "orange flares" and saying that the water was "very noisy ... very loud" at 2:45. Ukrainian president Volodymyr Zelenskyy said there was an "internal explosion" at 2:50 [a.m.]. According to The Economist, the explosions were so strong that they rattled windows 80 km (50 mi) from the dam.
Regional seismometers in Romania and Ukraine that were 600 and 500 km (370 and 310 mi) away detected signals that Norwegian Seismic Array (NORSAR) scientists interpreted as a weak seismic event in the area of the dam at 2:35 a.m. Ukrainian summer time, and a stronger, possibly magnitude 1 to 2 signal representing an explosion occurring at 2:54 a.m. (seismic waves, which travel at 6 km/sec in surface rock, would take approximately 83 and 100 seconds to travel 500 and 600 km, respectively).
NORSAR department head Ben Dando said the characteristics of the 2:54 signal corresponded well to those of an explosion but he said there was "too much uncertainty" on the magnitude, meaning that the power was equally uncertain. Officially collected data was not clear enough to establish whether there were one or two explosions, or even whether the signal of 2:35 a.m. represented an explosion. NORSAR CEO Anne Lycke said it was clear that the signal heard at 2:54 represented a man-made event, but it remains uncertain whether that signal was what caused the dam to collapse.
An infrared heat signature, consistent with that of a major explosion, was detected at the dam by United States spy satellites shortly before it collapsed.
Experts consulted by The New York Times (NYT) said on 7 June that the most likely cause was a blast from inside, adding that an attack from outside or a structural failure were less plausible. They said that blasts from outside—such as from a missile or artillery strike—would exert only a fraction of the force needed, and would also have accuracy limitations.
Ihor Syrota, the director general of the Ukrainian hydroelectric power company Ukrhydroenergo, rejected the possibility of shelling or catastrophic structural failure as Russian propaganda. Syrota stated that "the plant was designed to withstand a nuclear strike. To destroy the plant from the outside, at least three aircraft bombs, each of 500 kg, would have had to [have been] dropped on the same spot. The station was blown up from the inside".
Christopher Binnie, a water engineer specializing in dams and water resources development, and visiting professor at the University of Exeter, said the fact that there were "two breaches, either side of a structure", indicates that natural causes are highly unlikely. "Were the breach to be caused by excess upstream water level there would only be one". He also said it was highly unlikely the dam was breached by Ukrainian shelling, because to destroy the dam they "would need to get massive explosives close to the foundations".
The New York Times published another examination of the reason for the dam failure on 16 June. They consulted with Ihor Strelets, an engineer who spent months at the dam and served as the deputy head of water resources for the Dnieper from 2005 until 2018, who said the dam's huge bulk was mostly hidden below the waterline. A colossal block of nearly-solid concrete, 20 m (66 ft) high and up to 40 m (130 ft) thick at the bottom, held back the water. It also meant the Cold War-era dam could withstand almost any attack from outside. The sluice gates sat on top of this concrete, opening and shutting to adjust the water level in the reservoir. It became clear after the breach that not only the gates but also the concrete foundation had been destroyed. There had been earlier damage to the roadway over the dam and to some of the sluice gates (Ukrainian missiles had done some of this, as had retreating Russian troops). Also, a small part of a concrete wall separating the dam and the power plant collapsed on April 23 (44 days before the dam failed), which was said by NYT experts to be possible evidence of erosion near the dam.
According to the dam experts consulted by the NYT, neither this earlier damage nor the pressure caused by the high water level would have been enough to cause the structural damage to the dam foundation that occurred. There was a passageway inside the foundation that, according to experts, would have been the ideal location to plant explosives having enough force to blow up such a structure, and evidence suggests this is where they were planted. In the view of Nick Glumac, an engineering professor and explosives expert at the University of Illinois at Urbana-Champaign,