A water pump powered by the water it is pumping, no outside power source required. You can't go greener than this!
Basically a modern enhancement of the good old wooden water wheel, the Pelton turbine transforms kinetic energy from water into rotational energy, which can be used to create electricity and power a wide range of machines. To date, the Pelton turbine is the most common way of extracting hydropower, proofing its efficiency.
Allegedly invented by the great Greek philosopher Archimedes, the Archimedes screw is a device to elevate water from a low point to a higher point utilizing a rotating screw insidea pipe. This device is most often powered manually but can also be powered by wind. Using the screw in reverse is a way of harvesting hydropower. Not only great for watering your raised garden beds, the Archimedes screw is multifunctional!