１９９９年维系北京人民正常生活用水的官厅、密云两大水库的蓄水量已经到了“入不敷出”的程度 ;而地下水位则由７０年代平原地区的平均２～３米骤降到１４米左右。严重的水危机正威胁着北京市工农业发展和人们的正常生活 ,如何摆脱缺水危机呢？目前当务之急是施行节流开源 , The water volume of the two major reservoirs in Guanting and Miyun reservoirs, which maintained the water for normal life of the people in Beijing in 1999, has reached the level of “deficits in expenditures.” The water table has plummeted to about 14 meters from an average of 2 to 3 meters in the plains of the 1970s. A serious water crisis is threatening the development of agriculture and industry in Beijing and people’s normal life. How to get rid of the water shortage crisis? The top priority at the moment is to impose a cutback on revenue,