天下莫柔弱于水，而攻堅強者莫之能勝。

——老子（公元前6世紀）

Under heavern nothing is more soft and yielding than water．Yet for attacking the solid and the strong，nothing is better，it has no equal．

——Lao Tsu（6th Century B.C.）

Nature has not only demonstrated how to erode but also how to protect．It may safely be said that there is no protection initiated by man which has not before?hand been invented by nature，and nature obtained all the good results as well as all the bad results before man did．Consequently we can learn from nature if we will only make the effort of opening our eyes and looking．It must be admitted that nature has had more imaginative and has had more success than man．

——Bruun（1962）

自然在演示侵蝕過程的同時也告訴人們如何去防護。事實上所有防護方式均為自然發明而非人類原創，而且自然在人類之前已經知道了防護效果的好壞。因此我們只要善于觀察就可以從自然過程中學習。必須承認自然已比人類有更豐富的想象力和更多的成就。

——布容（1962）