进入90年代,我国的洪水灾害损失严重,而且有逐渐增大的趋势。原因是多方面的。首先,不利的自然地理条件致使我国洪灾频频发生;其次,河道萎缩、行洪能力锐减,在相同流量下的水位抬高许多,加大了洪水泛滥的风险;第三,河道防洪标准偏低,仅能防御一般洪水;第四,国民经济发展迅速,都市化程度愈来愈高,与河湖争地的局面日益严重,单位面积的灾害损失迅猛增长,等等。 Into the 90’s, China’s flood disaster suffered serious losses, but also gradually increasing trend. There are many reasons. First of all, unfavorable natural and geographical conditions have led to the frequent occurrence of floods in our country. Secondly, the river has shrunk and flood control capability has been drastically reduced, raising the water level under the same flow rate and increasing the risk of flooding. Thirdly, the standard of river flood control is low Fourthly, the rapid development of the national economy, the increasing urbanization, the increasingly serious competition for territory with rivers and lakes, and the rapid increase of disaster losses per unit area, and so on.