Not to discourage you but when we purchased our property had visions harnessing our small stream for hydro power.
Looked great in the spring after snow melt but by August it slowed down to a trickle.
As cowboyro
posted it is all about flow rate and head. Need a fair amount of both to make the project worthwhile.
In NC at least you don't have to worry about the stream freezing in winter.
/tom