Most micro-hydro setups seem to divert only part of the stream and only do it for a few hundred meters or so. These streams are typically much too small to be

Most micro-hydro setups seem to divert only part of the stream and only do it for a few hundred meters or so. These streams are typically much too small to be salmon spawning grounds or the like so the ecological impact seems pretty minimal. It's not like they're drinking all of the water, it gets returned to the stream right below the turbine.