Destroyed Ukrainian Dam Floods War Zone and Forces Residents to Flee

Ms. Shulzik said the Russian military had created a disaster. “I don’t know why they started this war, and why they carry on,” she said. “Agriculture will suffer, and the Black Sea will suffer because all this is flowing into the sea. Even the fish will suffer now.”

About 16,000 people total remained in the “critical zone” on the Ukrainian-controlled west bank of the river, said Oleksandr Prokudin, the regional military administrator. The National Police of Ukraine said that 23 towns and villages had been flooded so far, and that the water level in the Dnipro had risen by nearly 11 feet in the city of Kherson. By 9 p.m. local time, at least 1,366 people had been evacuated from flooded zones, the police said on the Telegram messaging app.

The destruction occurred a day after American officials said they had detected what could be the beginning of Ukraine’s long-anticipated counteroffensive to repel Russian forces east of the Dnipro in the Donetsk region. Russia’s military said it had beat back several attacks by Kyiv’s troops.

Sergei K. Shoigu, Russia’s defense minister, accused Ukraine of destroying the dam because it wanted to move forces and equipment defending Kherson to other parts of the front to help with its counteroffensive. Ukraine said it was Russia that blew up the dam to prevent Ukrainian troops from crossing the river downstream.

The dam, the southernmost one on the Dnipro, was built between 1950 and 1956 as part of a broader effort to capitalize on the economic power of the river known as the “Great Dnipro.” It was downstream from the Russian-controlled Zaporizhzhia Nuclear Power Plant, which relies on the Kakhovka reservoir to cool its reactors.

Initially, there was concern that if the river level fell far enough, the plant, Europe’s largest civilian nuclear facility, would be unable to draw water, potentially leading to a meltdown. But Ukraine’s state nuclear company, Energoatom, said in a statement that while the destruction “may have negative consequences” for the Zaporizhzhia plant, it had sufficient water for now from a nearby pond for cooling.