There was in the Free Territory of Ukraine under Makhno. Of course they were brutally crushed after 3 years because their succes and freedom was a threat to the Bolsheviks, and their legitimacy, who had already abandoned their ideals for power, as is inevitable when you concentrate power that much.
Dams can fail. Just look at Libia right now. And I know not every country is Libia, but pretty much all dams in the US are fucked too and nothing is being done about it. This is all very expensive infrastructure that needs constant upkeep and investment and is disastrous if that for some reason isn’t being done. Here in the Netherlands, there has been a massive project the past like 20 years to ‘give rivers space’ with wetlands and floodplains. It works well. I mean, we are literally the best in the world in managing water. 2 years ago a couple of rivers flooded. The city I lived in was already done with their part of the project. The floodplains flooded and everyone was safe, but another city which wasn’t done yet flooded and some cities in Germany and Belgium did too.