The dam was the last stage in the Dnieper cascade development, commissioned in 1959. It served principally for hydropower, irrigation water supply, and navigation.
According to sources close to the site, explosives were detonated on 6 June inside the powerhouse building, and the opinion in the region is that this act of terrorism was in response to Ukraine’s planned counter-offensive against the occupying Russian troops in the region.
The power station has been completely destroyed, and it has been estimated that reconstruction of the dam and plant will take at least five years, at a cost of about US$ 1 billion. The plant had been equipped with six units, and average generation had been 1.4 TWh/year.
The Kakhovka scheme was described in a paper in H&D Issue 2, 2021, in the context of a planned upgrade to the scheme, which was to involve the addition of four new generating, units totalling 250 MW of capacity.
H&D was told on 6 June that an additional danger now is that the (occupied) areas around the dam and powerhouse are heavily mined, and the floodwaters from the dam breach risk to detonate these.
The normal maximum reservoir level at the dam had been 16.5 m, but on the day before the disaster, the occupying forces had raised this to 17.5 m. After the initial breach, the maximum flow rate reached 21 400 m3/s; by 7 June this had begun to decrease. It was estimated on 7 June that the flooding would take three to four days to begin to subside, but before that the Antonovsky Bridge at Kherson was likely to be destroyed, and the port and dock area flooded. Also the right tributary of the Dnieper Ingulets would be likely to burst its banks.
Prompt evacuation procedures were effective in the 80 nearby settlements, with a population of around 16 000, and no deaths had been reported by 7 June, although casualties could not be ruled out, according to the National Security and Defence Council.
However the ecological and economic damage is huge. There are significant animal casualties across the region, and the zoo was completely destroyed. The loss of irrigated land in the southern regions of Zaporozhye, Dniepropetrovsk and Kherson will lead to a 14 per cent decrease in export potential of Ukrainian wheat. More than 200 000 residents in the area will be without drinking water, and the sewerage network has been destroyed, along with medical and food production facilities. Polluted water is reaching the Black sea.
It is expected that the most severe consequences of the flood will be on the left bank of the Dnieper (currently controlled by Russia). As we went to press, it was foreseen that in three to four days, the flood waters would spill into the Bug river, and could reach the city of Nikolaev. It was also predicted that 50 hours after the dam break, the Kinburn Spit, the isthmus behind the Dnieper Delta, would be completely flooded.
Kakhovka reservoir provided cooling water to the (occupied) Zaporozhye nuclear plant. While no immediate threat to the plant was reported, power to it from external forces has been cut, as well as regular radiation monitoring and emergency response measures, and communications with regulators. According to the Geneva Convention, destruction of a dam with explosives constitutes a war crime.