Picohydro.org.uk

This website includes information on ways to design, manufacture and install the various parts of pico hydro projects. It includes documents that you can download to assist in the process. Despite the fact that it hasn't been updated for a while, you'll learn the basics and download relevant documents. Don't hesitate to give your feedback or share other interesting resources with the Energy Community. 

http://www.picohydro.org.uk/