Okay, hear me out, I was just looking at pictures of beavers and thought to myself, what if someone used a beaver dam for hydropower? I mean my first thought is of course that wouldn't work...unless? I mean I know nothing about dam construction or hydropower, so I can't actually disprove this to myself. Why wouldn't this work? Or could it?
Not necessarily that it needs to be on a waterfall or anything like that since usually the thing to do is make an artificial lake so the dam itself acts as the waterfall. What I mean is the volume of water is probably too low to be worth doing.