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.