[seanmcdirmid]

Washingtonian here: they drill in the negative effects of hydro into our heads in high school civics class (but it’s primarily centered around fish). We still do it, but have began removing many of the older less productive dams in the state (eg on Elwa a few years back).

[snowwindwaves]

British Columbia has built about 125 new hydro plants in the last 30 years. The environmental studies take about 5 years and cost millions and employ many biologists and environmental specialists.

Negative effects can be mitigated if the plant is designed to take them in to account. Be it not changing flows and levels except very slowly to avoid stranding fish, keeping some water flowing past the intake structure to keep sediment moving, creating fish ladders, fish spawning channels, etc.

Hydro is really one of the least bad energy sources if you have to pick one.

[seanmcdirmid]

Sure, for new dams. The ones built a hundred or more years ago are the ones with huge problems. Well, there is always a cost, the Columbia will never run free, for example.

[snowwindwaves]

There must be some solution to the huge problems. The entities operating and maintaining these old hydro electric facilities probably don't have the budgets to resolve the huge problems, but it is hard to believe the situation is so bad and so hopeless that we'd be better off removing all of the dams and installing natural gas turbines in their place.