I feel that small scale hydro power is often overlooked these days and for the longest time I was part of that group.That was up until I visited a mountain hut in Bulgaria that was powered by a old cobbled together micro hydroelectric station.It was a amazing place that was off the grid long before that term was coined,everything comes in by foot or horseback and the power is from a small hydroelectric plant on a stream fed by snow melt.They really dont show or mention much about the hydro plant but nonetheless here are a few links,it's a truly gorgeous place nestled in the Rila mountains and worth the hike to get there.
http://www.ivanvazovhut.info/history_en.html http://gowhere.bg/en/guide/mountains/rila/ivan-vazov-hut/ivan-vazov-hut.htmlI say go for it and it isnt too hard to make a DIY pelton turbine although if you have enough flow I'd look into commercial options too as you'll probably see more power in the end.
Also one thing I see mentioned too often by people arguing against small scale hydro is they'll say you only have "X" amount of flow so it's only going to make so much power and I just love when they compare a 4kw hydro setup to a 4kw solar setup
.The part of the argument they neglect is that you dont have to go too far down stream to collect more power and that it runs nonstop (for the most part)
granted a lot depends on the setup but I saw a neat install where the outflow and bypass overflow from the main pelton turbine fed a old fashioned water wheel that was geared down to spin another generator.Granted the secondary wheel wasnt always on but it added capacity when flow allowed.
Good luck and if you go for it you'll probably be pleasantly surprised with the outcome no matter if you buy a commercial setup or go DIY with with as little as a bunch of spoons and a bike wheel attached to a alternator or 2 from a car.Once you have it setup and running it's going to quietly produce for you nonstop 24/7 365