Thanks for your reply. It usually is all about maintenance, isn't it? I like having something I can fix myself if it breaks. Although I am just beginning to learn about microhydro, I'm sure there is a simple enough system for me to be able to troubleshoot myself.
We are definitely old school here...we just bought the place about 18 months ago, and the irrigation consists of an open ditch that runs along the top side of the property, with "turn-outs" or "marks" running downhill to irrigate the pasture. Our house is at the "bottom" end of the ditch. This was the set-up when we bought the property. Needless to say, changing this is on our list, but we haven't done so yet which is fortunate because we have the option of installing the most efficient pipe for our needs, once we determine what those are!
As far as how much water we get...I recall that it is something like 7.5 gallons/second. And then by the end of August it is slowing down and may be about 3/4 to half that. I've never actually measured this, I think these numbers came from the ditch company that administers the ditch. The water is cut off at the end of September/early October. I am considering the benefits of digging ponds and possibly above-ground cisterns to hold the water on the property as long as possible. Could structures like these improve head pressure?