怎样保护北京的“两盆水”

Saving Beijing＇ s reservoirs

北京是严重缺水的城市，人均水资源占有量只有世界平均水平的1／30。官厅水库是1951年我国建立的第一座大型水库，流域面积4．3万km^2。建成以来，已累计向下游供水396亿m^3，年灌溉农田110万亩。但是，由于上游工业活动以及社区经济迅猛发展，官厅水库出现了全面退化，突出表现在来水量逐年减少、水质严重污染、泥沙淤积严重等方面。

Beijing suffers from a severe lack of water： the quantity of water available per head is only one - thirtieth of the global average. Guanting Reservoir, the first major reservoir to be built after 1949, drew water from a 43,000 - square - kilometre basin. Once completed, it provided a total of 39.6 billion cubic meters of water and irrigated 1.1 million mu （734 square kilometers） of land. However, upstream industrial and economic activity reduced the flow and polluted the water.