To crib a thought from a statistics hero, All dams are bad. Some dams are useful.
Dams alter and simplify ecosystems, they threaten native biodiversity, they’re a vector for invasive species. Dams cause flooding. All dams are temporary structures, many US dams are nearing their operational lifespan, some are already silting in, some are held together by duct tape and chewing gum, others never made a lot of economic sense in the first place.
But some dams are useful.
New research suggests solar farms could produce the same energy output as hydropower with a smaller footprint- placing solar farms in areas currently inundated behind dams could offset the losses from taking the hydropower facility offline.
It’s still largely a thought experiment, but certainly worth considering.