@Olivier5,
I haven't been reading about dams for quite a while, so I'm not clear what I think now about dams themselves. There was a lot of controversy about them in California some decades ago, and I presume there is still some, and that, I think, in at least one situation, involves tribal rights but I'm not sure there is any electrical power feature involved with that. I'll have to read up. Meantime, California (and many places) need to be able to store such water as does fall from the sky these days... or produced by desalinization, which I gather is expensive to do.
300 hydroelectric dams? sounds like a great many to me, but of course it's not just re water but the power it can provide. I should think there would/should be indigenous rights in place, but apparently not. Tough situation.