Where is the dam and what has happened?
The dam is located upstream of the city of Kherson on the Dnipro River in southern Ukraine. Russia controls the territory on the left bank of the river. The right bank is held by Ukraine.
In the early hours of 6 June, the dam collapsed.
Before its collapse, the 30-metre-high, 2km-long dam had a road running along its top. It powered the Kakhovka hydroelectric plant, a major energy producer, and held back a reservoir containing 18 cubic km of water that supplied communities and agriculture and provided cooling water to the nuclear power station at Zaporizhzhia, which is under Russian control.
How serious is the damage and the flooding?
Before-and-after satellite images show the extent of the damage to the dam and the adjacent Kakhovka hydroelectric plant, which were largely swept away.
The collapse sent water cascading downstream, flooding 230 sq miles of territory, according to Ukrainian authorities. This map shows the extent of the flooding as of 7 June.
The geography around the river means Russian-controlled areas to the south have been more badly hit. North of Kherson city, the land rises to a plain overlooking the river. To the south is a wide delta with marshes, low-lying islands and flat, sandy levels.
Video images from the city of Russian-controlled Nova Kakhovka showed flood waters in the main square rising around the municipal building on 6 June.
This footage shows flooding in Korsunka, Dnipriany and Nova Kakhovka – the three settlements immediately downstream of the dam on the Russian-controlled left bank of the river.
These before-and-after satellite images show the impact of the flooding on the settlements of Krynky and Oleshky.
These images show the flooding of a granary in Nova Kakhovka.
What has the humanitarian impact been?
At least five people have reportedly died as a result of the floods, a number that is expected to increase. Emergency services in the occupied southern portion of Kherson said on 8 June that up to 14,000 homes had been flooded.
Tens of thousands of people have fled their homes. Some of those who haven’t left have become stranded on rooftops as the water levels have risen.
This drone footage shows water being delivered by air to a family trapped in their house in Oleshky. They were later rescued.
Who was responsible?
Ukraine has blamed Russian occupying forces, which have had control of the dam and the adjacent town since last year’s full-scale invasion, of blowing it up in an attempt to ward off a Ukrainian counteroffensive.
The Kremlin says Kyiv sabotaged the dam to deprive Russian-controlled Crimea of the fresh water it receives from the reservoir and to distract attention from the counteroffensive.
Ukraine’s allies in the west have not directly apportioned blame to Russia, but they have questioned why Kyiv would want to destroy the dam. Engineering experts have said the collapse was most likely caused by a deliberate explosion inside the dam.
It is possible that the collapse was made more impactful by the fact that Russia had deliberately allowed water levels to rise in the reservoir behind it.
How will it affect Ukraine’s counteroffensive?
The delta area had been seen as vulnerable for Russian forces in part because of its low elevation.
The flooding has put paid – for now at least – to any potential Ukrainian attempt to cross the Dnipro River around Kherson/Nova Kakhovka by widening the barrier separating the two forces.
The loss of the road across the top of the dam also deprives Ukraine of a potential line of attack across the river, leaving only the Antonivsky Bridge in Kherson city as a paved river crossing.
The flooding may also allow Russian reserves in the south to block any move on Melitopol. And it could free up troop reserves concentrated in the south, allowing them to be directed elsewhere.
What is the impact on farming and the environment?
In the hours after the collapse, an adviser to the Ukrainian president, Volodymyr Zelenskiy, said “a global ecological disaster” was playing out. On 8 June Zelenskiy himself said that 50,000 hectares of forest had been flooded, and that 20,000 animals and 10,000 birds were “under threat of imminent death”.
This footage from upstream shows dead and dying fish on the drained bottom of the Nova Kakhovka reservoir on 7 June.
There are fears that the depleted reservoir will leave three critical regions in Ukraine’s “bread basket” without a key water supply. A series of canals run from the reservoir, all of which help irrigate swaths of agricultural land.
The most significant of these canals are the North Crimean canal, which supplies water to western Kherson before flowing down to Crimea, and the Kakhovsky canal, which irrigates most of the Kherson region’s fields before entering Zaporizhzhia.
Satellite imagery of the area directly south of the reservoir taken before the dam collapse shows mile upon mile of agricultural land.
Ukraine has warned that agricultural land in these regions could be so heavily affected that they could turn into “deserts”.
What is the impact on the Zaporizhzhia nuclear plant?
The cooling systems for Europe’s largest nuclear plant are supplied with water from the Kakhovka reservoir. If the dam falls below 12.7m, the lowest level at which water can still be pumped upstream to Zaporizhzhia, there are alternative water sources to keep the nuclear plant cool.