When accounting for all externalities, hydro doesn't usually pencil out all that well. It's a sad reality, because through a certain limited lens hydro looks amazing.

There are many efforts underway removing old hydro dams to restore the environments and ecosystems that were totally devastated by them.

A notable recent example is the Elwha River Dam removal that finished about 4 years ago in Washington: https://therevelator.org/elwha-dam-removal/