The effect/kinetic energy of the water involved would be comparable to that released by a nuclear explosion.
Total madness.
https://www.theguardian.com/world/2023/jun/06/nova-kakhovka-...
"The reservoir it contains holds an estimated 18 cubic kilometres of water, about the same volume as the Great Salt Lake in Utah. Bursting the dam could send a wall of water flooding settlements below it, including Kherson, which Ukrainian forces recaptured in late 2022"
In 1941 the retreating Red Army blew a different dam, the Dnieper/Dnipro dam, up to a hundred thousand people died on that occasion...
https://en.wikipedia.org/wiki/Dnieper_Hydroelectric_Station#...