Permaculture expert Geoff Lawton show us here how to trick water into flowing into the desired directions for maximum benefit.
Swales create a pocket for the water to pool. Even when swales overflow, the water is soaked up into the ground on an angle closest to the surface, making itself most useful for all growing things!
That is what permaculture explores and celebrates: maximizing what nature has already given us to work with, and being creative about closing some loops.