近50年来长江水资源特征变化分析

对长江水资源的特征如总量、用水量、水污染等的变化进行了分析,结果为:①1954-2004年流域平均降水量呈现下降趋势;长江上中游降水量的减少是导致宜昌、汉口水文站的径流量呈现下降趋势的主要原因,而大通水文站径流量呈上升趋势与汉口-大通间降水量增加有关;大通站1950到2004年的最小、最大月均径流量均呈上升趋势;长江水资源总量的变化主要受控于气候的变化。②水污染逐渐加重,水质有恶化的趋势,工业污染的增加是主要原因。③年均用水量占入海径流量的5.7%左右,人类活动尚未对长江流域总的水量构成很大的影响。结论:①长江水资源总量尚未发生巨大的变化,但由人类活动所造成的污染已对水资源的利用构成了影响;②南水北调工程的实施和长江三角洲工业的发展,使得中国东部地区对长江干流水资源的依赖性增加,加大了长江水资源利用的风险。

Variations in Water Resources of the Yangtze River over the Last Five Decades

This paper aims to reveal the change of some of the water resource characteristics such as total quantity,consumption and pollution in the Yangtze River basin in recent years.The data of water quality,water consumption and depletion are from the Yangtze Water Resource Report(1998-2004)which is published by the Ministry of Water Resources,China.The data of water discharge of the trunk river and the main tributaries are from the Yangtze Water Conservancy Committee.The dataset of precipitation in the Yangtze River basin is from the Information Center of the Weather Bureau of China.The results are:(1)The trend of average precipitation decreases in 1954-2004 in the Yangtze River basin;the decrease of precipitation in the upper and middle reaches induces the downtrend of the water discharge at Yichang and Hankou stations,while the increase of precipitation in the lower reach causes the uptrend of the water discharge at Datong station;both the minimum and maximum monthly average water discharge at Datong station shows an increasing trend from 1950 to 2004;the total quantity of water resource is mainly controlled by the variation of climate change.(2)More polluted water,which is mainly induced by the industrial development,is emptied into the rivers and aggravates the water quality.(3)Annual water consumption only accounts for 5.7% of the annual water discharge at Datong station which means that human induced significant influence on the quan-tity of water resources has not occurred yet.The conclusions are:(1)Though significant change in the quantity of water resource does not happen considering the intensified human activities in the Yangtze River basin in recent years,the aggravating water quality does have influence on the utilization of the water resources.(2)As the development of the industries in the Yangtze delta and the operation of South-to-North Water Diversion project,the eastern part of China will depend more on the water resources of the Yangtze River basin which might bring more risks on the safe utilization of water resources and sustainable development.