我国是人均水资源十分短缺的国家，人均占有的水资源为2500立方米（每年），仅为世界人均值的1/4，而且南方水多，北方水少，汛期降雨集中，非汛期干旱少雨。我国北方的黄河、淮河、海河流域工农业发达，人口稠密，而人均占有的水资源仅为500立方米（每年），是全国人均值的1/5 China is a country with a very short per-capita water resource. The per capita water resources is 2,500 cubic meters (per year), only 1/4 of the world average. And there are a lot of water in the south, little water in the north, heavy rain in the flood season and aridity in the non-flood season . In the north of our country, the Yellow River, the Huaihe River and the Haihe River Basin are well-developed in industry and agriculture, with a dense population. The water resources per capita is only 500 cubic meters (per year), which is one fifth of the national average