北京是一个严重缺水的特大型首都城市,随着城市人口的增加和规模的不断扩大,水资源的需求日益增加。尤其,1999年后连续干旱,密云水库来水量急剧减少,首都的供水安全受到威胁,如不开辟新的应急水源,一旦出现供水危机,将给首都的经济社会发展带来 Beijing is a mega-capital city with severe water shortage. With the increase of urban population and the continuous expansion of its scale, the demand for water resources is increasing. In particular, the successive droughts after 1999 have caused a drastic reduction in water inflow in the Miyun Reservoir. The water supply security in the capital is threatened. If a new emergency water source is not opened up and the water supply crisis will occur, this will bring about the economic and social development of the capital