You’d be surprised by the number of things that need to be constantly monitored. Building structures, power plants, roads, dams, mass transit, etc. basically everything.

Dams break and wreck havoc on ecosystems, the US has had it's fair share of coal mine sludge disasters. Even countries with strict environmental agencies and long history of mining have accidents.

So what's your solution? Stop building dams and decommission the ones that have been built? Humans attempt to create order. The universe naturally wants to increase disorder. It's natural that anything we create will need to be monitored.

We know that dams are dangerous and that they fail, the smaller ones are decomissioned when not in use not only to improve the ecosystem. A dam is not designed for a life of a 100 thousands years, it's a long time.