A deliberate explosion inside the Kakhovka dam, on the front lines of the war in Ukraine, most likely caused it to collse on Tuesday, according to engineering and munitions experts, who said a structural failure or an attack from outside the dam were possible but less plausible explanations.
Ukrainian authorities blamed Russia for the collse, pointing out that Moscow’s military forces – which have repeatedly attacked Ukrainian infrastructure since their invasion last year – controlled the dam spanning the Dnipro river, allowing them to detonate explosives from inside.
The Russian authorities, for their part, they blamed Ukrainebut they did not explain how.
For months, each side to the war has repeatedly accused the other of conspiring to sabotage the hydroelectric dam, without providing any evidence, accusations that rarely rose above the war fog of claims and counterclaims, both real and fabricated. .
Last week, both said that the attack on the dam was imminent; Ukrainian officials claimed that the Russians wanted to create a situation of emergency at the nuclear power plant Zorizhzhyawhich uses the river water for cooling, in order to paralyze an expected Ukrainian offensive.
“It was mined by the Russian occupiers. And they blew it up,” the Ukrainian president wrote on social media. Volodymyr Zelensky.
Ihor Syrota, director of Ukrhydroenergo, the state hydroelectric company, said in an interview:
“A missile attack would not cause such destruction because this plant was built to withstand an atomic bomb.”
And he added: “It is clear: there was an explosion from inside the plant and it split in half“.
But Dmitry S.Peskova Kremlin spokesman, told reporters:
“We are talking about deliberate sabotage on the Ukrainian side.”
John Kirbya spokesman for the White House National Security Council, said he could not comment who was responsible.
“We are working with the Ukrainians to gather more information,” he said.
Experts cautioned that the available evidence was very limited, but said an internal explosion was the most likely explanation for the destruction of the dam, a massive steel-reinforced concrete structure that was completed in 1956.
And local residents reported on social media that they had heard a big explosion around the time the dam broke, at 2:50 in the morning.
An explosion in an enclosed space, with all of its energy plied against the surrounding structure, would cause the most damage. Even then, experts say, it would take hundreds of kilos of explosivesat least, to break the dam.
An external detonation by bomb or missile would exert only a fraction of its force against the dam, and many times the explosive would be needed to achieve a similar effect.
“The payload cacity of a warhead is limited,” says Nick Glumac, an engineering professor and explosives expert at the University of Illinois at Urbana-Champaign.
“Even a direct hit may not kill the prey.”
“It takes a lot of energy,” he says.
“The forces acting on the structure are immense. We have the force of water, which is enormous. This is not like hanging on to a thread; these things are hard.”
During more than a year of heavy fighting, the Kakhovka dam has been repeatedly damaged, with each side accusing the other of shelling it.
The Russians ctured it last year when they pushed towards the Dnipro and beyond, but months later the Ukrainians drove Russian forces from the west bank, making the river – and the dam – part of the border between the warring sides.
The Russians held on to the dam.
It is not clear, however, that the damage sustained by the dam was sufficient to cause it to break.
“Dams fail; it’s absolutely possible,” said Gregory B. Baecher, a professor of engineering at the University of Maryland and a member of the National Academy of Engineering, who has studied dam failures.
But, he said, “I look at this and I’m like, ‘Wow, this looks suspicious‘”.
In August, a Ukrainian rocket hit the roadway of the dam.
In November, as Russian forces retreated across the river, an explosion destroyed part of the causeway; after that, images verified by The New York Times They showed damage to some of the gates that let the water through. But there was no indication of damage to the underlying structure.
Since November, the gantry cranes that open and close the gates have barely moved, though it was unclear if they had not been working.
This led first to record low water levels and then, as winter thaw and spring rains flowed into the reservoir upstream, to a record water level in 30 years.
Since the beginning of May, the water has risen above the gates and has passed the crest of the dam.
Satellite images taken last week showed the dispearance of more of the road; it is not clear if it was swept away by the current or destroyed by a blow.
Some dams have collsed from “overflow” from unusually high flows.
“Normally, such a breach would start on the land side of the dam, on either side,” explains Professor Baecher.
But photos and videos show that the Kakhovka dam broke first in the center, next to the power station adjacent to the Russian controlled shore.
At first both ends seemed intact, but as the day progressed the dam collsed more and more.
A combination of damaged gates and high water could pull out some gates but would not be expected to destroy much of the dam, the professor said.
On Sunday, Ukraine peared to launch a long-awaited counteroffensive against Russian forces, with those responsible claiming Moscow blew up the dam to block their advance causing floods and eliminating the only river pass that remained between the enemies.
It is not clear, however, whether Ukraine’s plans call for a major crossing of the lower Dnipro.
Ukrainians wondered why they would want to destroy their own infrastructure, cities and farms, while noting that these have been frequent targets in Russia’s brutal conduct of the war.
Moscow wanted to “show that it is ready for anything” if kyiv aggressively pursued its counter-offensive, said Roman Kostenko, chairman of the Ukrainian parliament’s defense and intelligence committee.
“They do everything they can to stop our counterattack“.
Peskov, a Kremlin spokesman, claimed that Ukraine had destroyed the dam to cut off the flow of water through a canal from the Dnipro to the Crimean peninsula.
After Russia illegally annexed Crimea in 2014, Ukraine halted the flow, but Russia resumed it last year after seizing the dam.
Other Russian officials claimed that the attack was intended to support a Ukrainian offensive that they claimed was failing, possibly to allow Kiev reposition some forces or for the floodwaters to push back the Russian artillery near the river.
Some Western military analysts were wary of trying to quickly blame anyone, or even saying whether the dam collse was intentional.
“It’s too early to tell,” said Michael Kofman, director of Russian studies at CNA, a research institute in Arlington, Virginia.
The disaster, he said, “ultimately does not benefit anyone“.
Contributed by Riley Mellen, Haley Willis, Thomas Gibbons-Neff, Paul Sonne, Andrew E. Kramer, Matthew Mpoke Bigg, Eric Schmitt, and Victoria Kim.
James Glanz is a journalist for the International section. He previously worked in the Investigation section and was head of the Baghdad office. He is a doctor of astrophysics from Princeton University and joined the Times as a science writer. @jamesglanz
Marc Santora reports from the Ukraine since the beginning of the war with Russia. He previously worked in London as a writer for international news focused on breaking events and was previously bureau chief for Central and Eastern Europe, based in Warsaw. He has also done numerous reports from Iraq and Africa. @MarcSantoraNYT
Richard Perez-Pena, an international news writer in New York, has worked at The Times as a reporter and editor since 1992. He has worked in the Metro, National, Business, Media and International newsrooms. @perezpena – Facebook