Water Power for the Farm is yet another great document from the CD3WD set compiled by the late Alex Weir.
I am a big fan of micro hydro and believe you should always use it if your site supports it. It is my conclusion that this is the most cost effective and efficient way to create power. Windmills rely on steady wind and solar relies on sun. However, if you have a suitable year round flowing water source you can get power 24-7-365
A constant supply of power can do a lot even if its just a trickle. Additionally water power has a lot of torque so it is useful in performing work and not just creating electricity.
A particularly creative farmer could rig a system to turn a shaft for mechanical power when needed and a turbine for electricity when not. A system using automobile transmissions was described in one of the foxfire books I read as a child.Water Power for the Farm