New Kakhovka Dam: Here are the main theories about what caused the catastrophic dam collapse in Ukraine



CNN

collapse Novokakhovskaya dam in the south of Ukraine is one of the largest man-made and environmental disasters in Europe for decades. The disaster destroyed entire villages, flooded agricultural land, deprived tens of thousands of people of electricity and clean water, and caused enormous damage to the environment.

It is still impossible to say whether the dam collapsed because it was deliberately targeted, or whether the breach could have been caused by structural failure. The dam and hydroelectric power plant are under Russian control and therefore inaccessible to independent investigators, so experts around the world are trying to piece together what happened based on limited visual evidence.

Several Western officials have blamed Russia for the disaster, either directly blaming Moscow for the dam attack or saying Russia is responsible simply because it is the aggressor in the war against Ukraine.

UN Secretary-General António Guterres called the destruction “another devastating consequence of the Russian invasion of Ukraine” but added that the UN did not have access to information to independently verify the cause.

A NATO military spokesman told CNN that while it will be some time before they know for sure who is responsible for the destruction of the New Kakhovka Dam in Ukraine, they believe that Russia is probably behind it. The official added that Russia would stand to gain the most from the move, which could potentially slow down an expected Ukrainian counteroffensive if it occurs in that part of the country.

Satellite images of the Novokakhovskaya dam before its collapse (left, June 5) and after the accident (right, June 7).

A number of construction experts have suggested that an explosion inside the structure is the most likely cause of the dam failure, although this is not the only possible explanation.

Here are three main theories about what caused the crash, and what experts and officials have to say about each:

Ukrainian President Volodymyr Zelensky, his government and military countries were quick to blame Moscow for the disaster. They said Russian troops blew up the reservoir from the inside, while Zelenskiy cited a Ukrainian intelligence report last year that claimed occupying forces mined the dam.

The Ukrainians note that the facility has been under Russian control for the past year, making it easy for Russian forces to plant explosives.

According to social media reports, people in the area heard the sounds of explosions around the time the dam was thought to have been damaged.

The broader time of the incident is not insignificant. While Moscow and Kyiv have previously accused each other of plotting to blow up a Soviet-era dam, the collapse coincided with Ukrainian forces preparing for their widely anticipated operation. Summer counteroffensive.

The dam blocks the Dnieper River, a major waterway that has become a front line in the conflict and the scene of fierce fighting in this part of southern Ukraine. City Kherson, which is located on the western bank of the Dnieper, was liberated by the Ukrainian military in November after eight months of Russian occupation. But much of the eastern bank of the river south of Novaya Kakhovka remains under Russian control.

Ukrainian forces are increasingly shifting the fighting to Russia’s fortified front lines to the south and east, with Kyiv blaming Russia for the dam explosion “in a panic.”

As Zelensky’s senior aide Mikhail Podolyak said, “the goal of the terrorists is obvious – to create obstacles for the offensive actions of the Armed Forces of Ukraine.”

“This once again confirms that the Kremlin does not think strategically, but in terms of short-term situational advantages. But the consequences are already catastrophic,” he told CNN.

The damage also affected the area north of the reservoir, where water levels are falling. As a result of the collapse, 94% of irrigation systems in Kherson, 74% in Zaporozhye and 30% in Prydniprovska oblasts were left “without a source of water,” according to the Ministry of Agriculture of Ukraine.

The Zaporozhye NPP is also located upstream of the collapsed dam. The reservoir provides cooling water to the power plant, Europe’s largest nuclear power plant, and is critical to its safety. The plant is under Russian control, a major source of concern for Ukrainians still frightened by the 1986 Chernobyl nuclear disaster.

Russia denied any involvement in the disaster and, in turn, accused Ukraine of destroying the dam, without providing evidence.

Kremlin spokesman Dmitry Peskov said the attack was “planned and carried out on orders received from Kiev, from the Kiev regime” to “deprive Crimea of ​​water” and draw attention away from the battlefield. Ukraine denied the allegations.

The reservoir supplies water to large areas of southern Ukraine, including the Crimean peninsula, which Russia illegally annexed in 2014.

Crimea has been experiencing water problems since Ukraine cut off water supplies shortly after annexation. Russian troops seized the North Crimean Canal, fed by the Kakhovka Reservoir, and began restoring water supplies in the early days of their invasion in 2022.

While the flooding is likely to affect any Ukrainian counteroffensive, it will also affect Russian forces. Some areas worst hit after the disaster are under Russian control and in the past served as a springboard for the Moscow military.

The Ukrainian city of Korsunka in a satellite image on June 7 after flooding caused by a collapsed dam.

There are also suggestions that the collapse of the dam caught at least some Russian forces by surprise.

A Ukrainian military officer told CNN that his men witnessed Russian soldiers being swept away by flood waters and fleeing the eastern bank of the Dnieper River. Capt. Andrei Pidlisny told CNN in a phone interview that when the dam burst early Tuesday morning, “no one on the Russian side could get away. All the regiments that the Russians had on the other side were flooded. CNN cannot independently verify his account.

Russia has accused Ukraine of “massive artillery shelling” of the dam, but some experts question whether it is possible to cause destruction on this scale from outside.

Several experts cited an internal explosion as the more likely explanation.

“Ukrainian shelling is unlikely as it would need to place massive explosives close to the foundation,” Chris Binnie, visiting professor at the University of Exeter and chair of tidal engineering and environmental services, told the British Science Media Centre.

Craig Goff, technical director and head of the dams and reservoirs team at HR Wallingford, a civil engineering and environmental hydraulics consultant, said it would take a very precise strike to cause enough damage to the dam.

“Even during the Second World War, there were [Royal Air Force] Dambusters are attacking German dams and they had to spend a lot of time figuring out exactly where to place the explosives on the dam in order to cause enough damage to cause it to burst,” he told CNN.

“It wasn’t easy. You had to deliver the explosives directly downstream from the dam to a great depth. If it was only the top of the dam, it would probably still survive. You will lose some water, but it will survive,” Goff said.

The Novaya Kakhovka Dam, Ukraine’s largest reservoir by volume, is also the furthest downstream of the six Soviet-era dams on the Dnieper River. The fact that the facility has been in operation for many decades has raised speculation about a possible technical failure.

“The section of the dam we are considering is a concrete gravity dam 35 meters high and 85 meters long (115 feet high and 279 feet long). This is a very common type of dam throughout the world. They have been built for hundreds of years, and if they have been designed and built well and properly maintained, then the chance of failure is very, very low. It is highly unusual for this type of dam to fail without warning,” Goff said.

However, it is not clear how well the dam survived during the Russian occupation. The surrounding area has been one of the most contested regions ever since Russia launched its full-scale invasion of Ukraine in February 2022, and the dam has already suffered some damage.

Sections of the northern part of the dam and some lock gates were also hit by an explosion in November, during the retreat of Russian troops from the western bank of the Dnieper and the liberation of Kherson by Ukrainian troops.

A CNN analysis of satellite images from Maksar shows that the road above the dam was damaged just a few days before the structure collapsed. Satellite images show that the bridge was intact on May 28, but images from June 5 show that part of the same bridge is missing. Analysis of lower resolution satellite imagery suggests that the loss of the bridge section occurred between June 1 and 2.

Meanwhile, data show water levels in the reservoir behind the dam were at an all-time high last month, according to news service Hydroweb.

“The images I saw show two gaps on either side of the structure. If the disturbance were caused by excess water levels upstream, there would be only one. These natural causes are highly unlikely,” Binnie said.

“The design of the dam will accommodate this very high water level, even extreme biblical type flooding, and there will be spillways to allow the water to overflow. So, again, the dam should not collapse just because of the high water level,” added Goff.

Experts are also considering whether a failure within the power plant could have caused the collapse. Goff pointed to the 2009 explosion at the Sayano-Shushenskaya plant, the largest hydroelectric power plant in Russia. “In this particular case, there was a problem with one of the turbines. It vibrated and eventually the turbine exploded. And it killed people inside the power plant, but in this case it didn’t affect the dam because of the way it was built,” he said.

“It is possible that if the hydroelectric power plant was at a critical point inside the dam and something bad happened in that power plant, it could cause an explosion inside that would damage the dam,” Goff said. However, he added that such an incident without prior warning is “highly unlikely.”

“You would know how to operate the dam safely, and you would know that the turbines shouldn’t vibrate so much… so if it was looked after properly, you could probably rule it out,” he said.

But since the plant was under Russian control for over a year, no one can be sure what went on inside during that time, and it’s far from certain that those who ran it knew what they were doing.