Apologies to SuzieQ for temporarily hi-jacking her wind thread...
but hydro is another matter - MAB would be interested in your journey how can I best learn about DIY pico hydro?
Hmmm... it's not much of a journey yet - mostly a though experiment and a costing exercise.
the first link gives a simple calculator that shows the power you might be able to extract from your water:-
http://www.reuk.co.uk/Calculation-of-Hydro-Power.htmyou also need to determine what type of wheel / turbine you need. If you have a lot of head (pressure) and low flow (like me) then you probably want a pelton or turgo turbine; if you have a lot of flow but a low head then a wheel of some sort may be the way to go. this website might give you some ideas:-
http://www.navitron.org.uk/page.php?id=58&catId=70the good thing about turbines is you don't need huge aqueducts but the turbines are difficult to diy build and expensive to buy.
The good thing about waterwheels is that they are easy to homebuild, but you may need to do a lot of digging to get the water to them.
if you're using a turbine and can pipe the water to it, then this calculator works out what size of pipe you need to keep your frictional losses below 10% and what size of cable you need (for their genny) to carry the power to the house:-
http://www.powerspout.com/advanced-calculator/I've worked out I need about £500 worth of pipe to get the water to where my turbine will be

then I ned to buy (£1000?)/make the turbine and genny; then I need about £100 worth oc cable to get the power home.
that's as far as I've got.

Oh, I've just found this site as a possible source of affordable turgo 'spoons' and wheels:
http://h-hydro.com/If Dan will forgive a link to another forum, the following is a good place to discuss all things renewable energy/off grid:-
http://www.fieldlines.com/Hugh Piggot has a website for his wind stuff (and I note he now supplies the powerspout turbines) and you can order a copy of his book on how to build a windgenny (genny doesn't HAVE to be used on a windmill).
http://scoraigwind.co.uk/OK we can go back to wind now

M