Don't forget everyone who lives downriver from that dam all the way to the ocean. Living next to it but out of the path of the water, or above it, would be fine.
I used to live in a small city on the coast that was a 20 minute drive from a nuclear plant and also downstream from a hydroelectric dam.
number of people who could live next to a dam: "small"
number of people who could live next a nuclear power plant: "much, much larger"