Video Clips providing some background insight:

An Introduction to Hydropower:

         http://www.youtube.com/watch?v=A4UaWt_pReY

Hydro on a big scale - How it Works:

         http://www.youtube.com/watch?v=cEL7yc8R42k

Sample Turbine - Pelton Wheel:

         http://www.youtube.com/watch?v=Jd5BN7SPkqI

Farmer in Wales with a micro-hydro:

         http://www.youtube.com/watch?v=YI1JlIpM6V8

20kW off-grid scheme in Kenya:

         http://www.youtube.com/watch?v=w5r9281c6Tg&$$feature=channel&list=UL

A small Archimedes Screw scheme:

         http://www.youtube.com/watch?v=ib8aTy3uxKs&;feature=channel&list=UL