Hsu Shih-hsiung cites Japan as an example: the Japanese long ago recognized the dangers of excessive gravel extraction; there was a period when they did not use their own gravel, but sent ships to carry from Hualien.
許時雄舉例說，日本早警覺到過度採沙的後果，有一段時間，自己的沙石不用，船開到花蓮港來載沙。