I have read assertions that Ukrainian shelling was insufficient to destroy the dam. At the same time, we also know the Russians mined the area. Is there any chance, unwittingly, the two sides could have damaged it together?
I guess there are 6 possible scenarios
1. Russians deliberately
2. Russians accidentally
3. Combination, but mainly natural causes / wear-and-tear
4. Ukrainians deliberately
5. Ukrainians accidentally
6. Combination Rus / Ukr accidentally
The most plausible explanation seems to be 2, followed by 6, then followed by 3. Either way, you could argue, as the occupying power Russia is more culpable for 3 and 6, especially as they should be maintaining the dam and they also employed explosives to a vulnerable infrastructure.