水是人类赖以生存和发展的基础资源,是国家最宝贵的自然财富。我国虽是水资源大国,但由于人口众多,人均拥有的水资源却不多,越来越难以满足人口增长和社会发展的需求。更为不利的是水资源的地区分布南多北少,与人口和其它资源的分布极不匹配。以长江流域北缘为界,北方的国土面积和矿产资源约占全国的60%以上,耕地面积约占全国的2/3,人口约占全国的45%,而水资源却不足全国的20%。因而北方水资源普遍短缺。其中,华北地区人口密集,经济发达,缺水尤为严重和紧迫;西北广大地区由于缺水,致使土地沙漠化和荒漠化,风沙横行,沙漠日渐东进南下,酿成可怕的生态环境灾难。这一地区目前 Water is the basic resource on which mankind depends for survival and development and is the country’s most precious natural wealth. Although our country is a large water resource country, due to its large population, there is not much water resource owned by each country, making it increasingly difficult to meet the needs of population growth and social development. Even more disadvantageous is that the geographical distribution of water resources is less in the south and north than in the north, greatly mismatching the distribution of population and other resources. Taking the northern margin of the Yangtze River Basin as a boundary, the land area and mineral resources in the north account for more than 60% of the country’s total. The cultivated area accounts for about 2/3 of the country’s population, with a population of about 45% of the country’s population, while water resources are less than 20% . As a result, there is a general shortage of water resources in the north. Among them, the densely populated and developed economy in North China is particularly serious and urgent due to the shortage of water. Due to lack of water, the desertification and desertification of the land in northwestern China have led to the desertification of the land and desertification. As a result, the desert has gradually moved eastward to the south, causing terrible ecological and environmental catastrophes. This area is currently