POKROVSK, Ukraine — Russian forces have blown up the dam on a river in eastern Ukraine, sending water levels rising in what Ukraine’s military on Friday said was an effort to flood its supply lines downstream.
The missile strike Thursday afternoon on the floodgates of the Karlivka dam in eastern Ukraine’s Donetsk region marked what appeared to be the latest use of flooding as a tactic in the 15-month-long war. The rivers that crisscross Ukraine present some of the few natural barriers between Russian and Ukrainian forces, and both sides have used them to block advances or sought to target the other’s pontoon bridges.
Roiling torrents of water flowed from the destroyed dam, according to video footage shared on Thursday by the head of Ukraine’s military administration in the region, Pavlo Kyrylenko, on the Telegram messaging app. He said the local authorities had evacuated 26 people from homes and that villages downstream on the Vovcha River were put on flood alert.
Russian forces have “constantly bombarded” the dam for months, Mr. Kyrylenko wrote on Telegram, before scoring a direct hit on its floodgates.
“Civilians will suffer primarily from these actions,” he said.
The flooding inundated an area of intense Ukrainian military operations near the front line. The military closed the area downstream of the dam, citing security concerns.
“Russia is predictable in its actions,” Maj. Serhiy Tsekhotsky, a spokesman for Ukraine’s 59th Brigade, which operates in the area, said in an interview. “They do the same thing again and again.”
Both Ukraine and Russia have throughout the war used rivers and their crossings to stymie the other side’s advances.
In the first days of the war, the Ukrainian military blew up the gates of a dam to flood the Irpin River valley to the north of Kyiv, blocking one route into the capital for Russian tank columns and buying time to prepare defenses, but flooding several dozen homes in the area.
Last September, Russian forces fired a volley of missiles at a dam near the city of Kryvyi Rih in central Ukraine, blowing up one of two floodgates in what Ukrainian officials said was an effort to wash out Ukrainian military pontoon crossings downstream on the Ingulets River. Ukraine needed the pontoon crossings, which were also attacked by Russian artillery and aerial bombardments, for a counteroffensive that eventually succeeded in driving Russian forces out of the city of Kherson.
In an indication of the value of that dam as a military target, Russia fired seven of its most sophisticated Iskander and Kinzhal rockets at the floodgates. But only one of the two floodgates was damaged, local officials said at the time, resulting in a more gradual release of water from a reservoir than if the strike had destroyed both.
The pontoon crossings downstream were not affected, but the water level in the Ingulets River rose by two meters and inundated neighborhoods in Kryvyi Rih.
Ukraine’s government has repeatedly warned of the risk that Russia will blow up a major hydroelectric dam on the Dnipro River to release water from the Kakhovka Reservoir. Ukrainian officials have suggested that the goal of such a strike would be to flood riverside communities and Ukrainian military sites downstream or to create an emergency at the Zaporizhzhia nuclear power plant, which draws cooling water from the reservoir.
Russian forces, who occupy the eastern bank of the river at the site of the Kakhovka dam and control the floodgates, have already for unclear reasons manipulated the water level in the reservoir, according to Ukrainian officials.
Over the winter, the water level in the reservoir dropped to its lowest level in four decades, depriving Ukrainian towns upstream of water supplies. During a period of high snowmelt in the spring, Russia’s military allowed water to accumulate to what Ukrainian officials said were levels so high they posed dangers to the integrity of the dam.
Altimetry data — which uses satellites to measure height — published last week by Theia, a French earth data provider, showed water levels at the reservoir have reached a 30-year high, increasing the possibility of flooding in the area and signaling a lack of regulation.