Russians started trying to deny it, but this is not credible.
Sources and timeline in this thread:
I start to be concerned about Zaporizhzhia again
The Russians trying to deny this is absurd because they are literally the only people who benefit from it. The only reason to blow up the dam and flood Kherson is to prevent a crossing there. The fact that the dam has been blown today tells me the Ukrainian counteroffensive is taking place, because:
The main problem for Russia is, as it was during the Kharkiv and Kherson counteroffensives, distribution of forces. At that time they did not have enough men to adequately defend each front, so they lost territory to the Ukrainian army. They could not blow the dam back then because half their army was on the other side of the Dnieper. But this time they're all east of it.
My guess is Ukraine is hitting Russia in Zaporizhia and/or the Donbas right now and the Russians are panicking, they've blown the dam to render the Kherson front completely unassailable to Ukraine so they can rapidly reinforce the rest of the front without weakening their defenses there.
Ukraine would be retarded to blow the dam because even if they have no plans to attack in Kherson, they need the Russians to think they might so they maintain large forces there. All this would achieve is making it easier for Russia to concentrate force in the east and thus harder for them to attack.
This is likely also the reason for the incursions into Belgorod - it forces Russia to commit troops to the border instead of the frontline. Anything that thins the Russian forces is good for Ukraine; anything that enables shifting more troops to fewer places is good for Russia.
And before Russia inevitably blames glowies from the West (probably the UK specifically, apparently the Brits are responsible whenever a bear sneezes in eastern Europe) that makes no sense either because again, we don't benefit from helping Russia eliminate one vector of Ukraine's attack, and we also don't benefit from risking a nuclear disaster at the Zaporizhia nuke plant.
Russia did this, 100%, because Ukraine is on the offensive and they need those troops for the eastern sector. If I'm wrong then some incredibly stupid people did something extraordinarily stupid. And yes, this is a war crime. Frankly it's beyond the pale.