Thanks for that, the first review!
I envisaged the narrator as living downstream from the dam, and the section of the river where they live being greatly reduced in it's outflow.
I'm not against dams per se, just the huge megadams which muck up the environment so badly. And those seem to be the ones that are getting built these days. The fish stocks, the farming, everything that depends on the river, tend to disappear or become greatly reduced. It's appalling.