The syphon

I went on a walk this morning with my brother who is staying with us. As time was short, we chose a contour walk along an irrigational canal at the end of which is this unusual syphon. The water flows down a canal on one side of the valley and then crosses the valley bottom and emerges half way up the other side of the valley. Using the same principle as syphoning petrol from a tank, the water is conveyed up the opposite slope in a pipe and can then gently descend the contours to irrigate land below. Simple but clever.