Hydro is not green at all. Nuclear is much better for the environment than hydro.
This can drop to almost zero, if you build a dam near a location with preexisting cement plants, or, in an area where you snap build your own cement plant.
Even steel transportation ; is it local? Is their train? Is there a waterway, which ships can transport steel to you on?
Hydro is so clean, it isn't even funny.
Rivers naturally shift on their own. In North America, the land is still rebounding from the last ice age.
And it's not like the land is rendered hostile to life. A river becomes a lake.
And as there are beaver dams which can be seen from space, I'd have to say Beavers impact rivers far more than our measly few hydro dams.
It's normal, natural for rivers to be dammed.. it happens in nature all the time, unless you believe beavers are unnatural?