First off, welcome to the site! Its cool to see someone here interested in hydro power.
Would you be able to pipe off the river and go downhill to a generator station? The greater the head of water you can get the more power you'll get out of the system. I posted something like this a while back.
http://ecorenovator.org/forum/other-...ric-setup.html
We did have a post on a book about a water wheel farm setup here.
http://ecorenovator.org/forum/other-...ty-1915-a.html
Builditsolar.com is also another vast resource of info that I would check out.
Small Scale Hydro -- Ram Pumps and Water Motors