1981年8月在法国格勒诺布尔召开的第十一届国际灌排水会议上,在讨论防洪问题时,代表们明显地意识到“目前之防洪趋势似已由工程性措施转向非工程性措施”。洪水平原上的土地有易受洪水淹没不利的一面,又有土地肥沃、经济开发价值高的有利一面。为了达到合理管理的目的,首先须对洪水平原进行区划,把不宜开发的土地与必须开发的土地加以区分。美国通常以百年洪水位为 At the 11th International Conference on Irrigation and Drainage held in Grenoble, France, in August 1981, when discussing flood control issues, delegates clearly realized that “the current flood control trend seems to have shifted from engineering measures to non-engineering measures ”. Flood plains of the land vulnerable to flooding the unfavorable side, there are fertile land, the high value of economic development, the favorable side. In order to achieve the goal of sound management, first of all, the flood plains must be zoned to distinguish between land unfit for development and land that must be developed. The United States usually floods for centuries