Make your own river water pump that works on gravity. via instructables
Pump water with no electricity, no gasoline, just gravity!
Sound crazy or impossible? Don’t worry, it does obey the laws of physics, but I’ll try to explain the operation later. This instructable shows how to build a fairly simple water pump that needs no energy input other than water flowing from a higher point to a lower point. Most of the pump is constructed from PVC, with a couple of bronze pieces thrown in for flavor. I was able to source all of the parts from a local hardware store (Lowes) for a bit under $100.
To function, the pump does require a reasonable amount of water that will drop at least 3′-5′. The level that the pump can raise water to depends on the water’s head (total drop the water will make).