Interestingly, concerns that the dam was dangerously over-full were reported last month, with water spiling over the wall at times. This came not long after it was at a historic low, possibly indicating the Russians purposely filled it to over capacity prior to destroying it in order to get the maximum effect. Another exhibit for the prosecution at the war crimes trial.
"Russian-Controlled Dam Risks Flooding in Southern Ukraine
The development is a dramatic turnabout after the reservoir had reached a historic low. The dam, which lies along the front line, has been a point of tension throughout the war."
Russian-Controlled Dam Risks Flooding in Southern Ukraine - The New York Times (nytimes.com)