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我国长江、黄河、淮河、海河、珠江、辽河及松花江等七大江河,其流域面积虽然只占全国国土面积的45％,但人口占全国的77％,耕地占全国的80％,几乎包括了目前我国经济、文化最发达的地区。这些地区的地面高程多在江河洪水位以下,受江河洪水的威胁很大。大江大河一旦失事造成洪水泛滥,均直接影响我国的社会安定、经济发展、生态环境和人民生命财产的安全。历史上,七大江河洪灾频繁,损失惨重。据统计,长江从汉朝至今发生洪灾200余次;黄河在解放前的2000多年中,决口泛滥1500多次,大改道26次;淮河自1194年下游河道被黄河夺截后的500年间,发生水灾350余次;海河在解放前的580多年间发生水灾367次,近300年来,
Although the Yangtze River, the Yellow River, the Huaihe River, the Haihe River, the Pearl River, the Liaohe River and the Songhua River have a catchment area of only 45% of the country’s total land area, the population accounts for 77% of the country’s population and 80% of the country’s arable land, covering almost all At present, China’s economy and culture of the most developed areas. The surface elevation in these areas is mostly below the flood level of rivers and is at great risk of flooding from rivers. Once floods occur in major rivers, the floods directly affect our social stability, economic development, ecological environment and the safety of people’s lives and property. Historically, the seven major rivers flooded frequently and suffered heavy losses. According to statistics, there were over 200 floods in the Yangtze River since the Han Dynasty. During the more than 2000 years before the liberation, the Yellow River flooded more than 1,500 times and drastically changed roads 26 times. During the 500 years after the Huai River was intercepted by the Yellow River in 1194, Floods more than 350 times; Haihe River in the 580 years before the liberation of floods occurred 367 times, nearly 300 years,