The New York Times reports:

Even in a war that has razed entire cities, the destruction of the Kakhovka hydroelectric dam in southern Ukraine stands out.

Thousands of people were displaced by flooding from one of the world’s largest reservoirs, which was vital for irrigating farmland considered the breadbasket of Europe. The disaster puts global food supplies for millions at risk and could threaten fragile ecosystems for decades.

The dam was visibly scarred by fighting in the months before the breach. Ukrainian strikes had damaged one part of the roadway over the dam, and retreating Russian troops later blew up another. Last month, satellite images showed water flowing uncontrolled over some of the gates.

This has led to suggestions that the dam may have merely fallen victim to the accumulated damage, which Russia has seized on to deny responsibility.

But multiple lines of evidence reviewed by The New York Times, from original engineering plans to interviews with engineers who study dam failures, support a different explanation: that the collapse of the dam was no accident. The catastrophic failure of its underlying concrete foundation was very unlikely to occur on its own.

Given the satellite and seismic detections of explosions in the area, by far the most likely cause of the collapse was an explosive charge placed in the maintenance passageway, or gallery, that runs through the concrete heart of the structure, according to two American engineers, an expert in explosives and a Ukrainian engineer with extensive experience with the dam’s operations.

“If your objective is to destroy the dam itself, a large explosion would be required,” said Michael W. West, a geotechnical engineer and expert in dam safety and failure analysis, who is a retired principal at the engineering firm Wiss, Janney, Elstner. “The gallery is an ideal place to put that explosive charge.”

Engineers cautioned that only a full examination of the dam after the water drains from the reservoir can determine the precise sequence of events leading to the destruction. Erosion from water cascading through the gates could have led to a failure if the dam were poorly designed, or the concrete was substandard, but engineers called that unlikely.

Ihor Strelets, an engineer who served as the deputy head of water resources for the Dnipro River from 2005 until 2018, said that as a Cold War construction project, the dam’s foundation was designed to withstand almost any kind of external attack. Mr. Strelets said he, too, had concluded that an explosion within the gallery destroyed part of the concrete structure, and that other sections then were torn away by the force of the water.

“I do not want my theory to be correct,” Mr. Strelets said. A large explosion in the gallery might mean the total loss of the dam. “But that is the only explanation,” he said. [Continue reading…]