http://www.landtohouse.com/learn-about-ram-pumps/

Watch the video at the above link….

In countries like Malawi, where water problems are often twinned with lack of power supply in many rural areas, there is a real need for pumps such as these since they don’t need electricity to work.

More about Hydraulic Ram Pumps can be found here https://www.youtube.com/watch?v=Zk9zs0EQIQ8 .

Comment: Considering the narrators surmise that these pumps waste a lot of water, one would think if the waste water on the outlet valve is being delivered back into the water source, by a pipe system of some sort that feeds back into the river or lake, then the water is not really being wasted.