Exploitation and Utilization of Water Resources and Drought Ecological Environment of Beijing

Li Xianfa, Li Anfeng
(Beijing Municipal Research Institute of Environmental Protection, Beijing 100037)

The area of Beijing is 16800Km2, of which the mountainous area is about 62 percent, and the plain area is 38 percent. In 1956--1995, average yearly rainfalls were 595 mm and the evaporation of water surface was 1120mm, The population of Beijing was 2.092 million in 1949. It had increased to 12.234million by 1998.
Water resources of Beijing consist of water generated in this region and wate from upriver regions. Av- erage yearly amount of one-off water resources was 6. 28 billion m3 in 1961--1995 Since 1949 , 85 reser- voirs have been built, whose capacity is 9. 3 billion m3 . Besides, thousands of cisterns and sluices have been constructed , which can store 0.3 billion-m3 water. The actual water supply of surface water is.respectively l. 55 billion m3 in common year, 1.17 billion m3 in low water year and 0.79 billion m3 in dry year. The average yearly amount of allowable exploitation of ground water is 2.63 billion m3, about two thirds of to- tal water supply.
The excessive water consumption and serious loss of ground water are the main problems caused by ex- ploitation and utilization of water resources. According to. approximate estimate , average yearly water con- sumption was about 4. 75 m3 in 1961--1965 about 75 percent of one-off water resources. The evaporation consumption of water conservancy projects is more than 30 percent of totaL water consumption and the con- sumption of water use is more than 60 percent. The accumulative loss of ground water adds up to 4. 3 bil- lion m3, and the plain area of excessive exploitation is 2660 Km2, about 41 percent of total plain area. The
declining of ground water level in near suburbs results in water level funnel. The funnel area is more than 1000 km2 and the water level in funnel center of eastern suburbs has declined 40---50m Consequently, fountains almost dry up, the water in surface layer of soil gets less and less and there exists a potential risk of hungriness. There are two main factors affecting the loss of ground water. On the one hand, ground water is excessively exploited yesr after year; on the other hand, the replenishment of ground water de- creases, which is caused by the reducing of dank area.
Excessive loss of ground water and water consumption in explotiation and utiLization of water resources have been attached importance to. Countermeasures that are being researched and have been adopted in- clude developing water-saving agriculture and maintaining ground water. developing underground reser- voirs. Detailed measures of the latter include adjustment jointly of ground water plants and surface water plants, ground water recharge by riverway, ground water recharge by sandstone pit and storm water infil- tratlon .
Foreign environmenetal experts regard the declining of ground water Level as one of the fateful envi- ronmental problems in 21 century. At the same time, they point out that cutting down water consumption can increase water supply. Though great efforts have been made to save water and to maintain ground wa- ter , the declining of ground water leveL has not been controlled efficiently yet. So some advicis given in the paper, such as saving water use of agriculture and altering structure of agriculture, cutting down water consumption of agriculture; establishing layouts and measures of maintaining ground water and ground wa- ter recharge, and so on.
As far as exact estimate of water consumption and ecological problems caused by the declining of ground water level, it is only a cursory discussion in the paper and needs further research.

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