《管子·度地》
水的性质，走到曲折的地方，就停而后退，满了，后面就推向前进，地低则走得平稳，地高就发生激荡，地势曲折就将冲毁土地。
水之性，行至曲必留退，满则后推前，地下则平行，地高即控，杜曲则捣毁。
The nature of water is that when it reaches a bend, it stops and then recedes, when it is full, it pushes forward the water behind, if the ground is low, it flows steadily, if the ground is high, it becomes turbulent, and if the terrain is rugged, it will erode the land.