Analysis of Variations and Factors of Water Use Amount per Ten Thousand Yuan GDP in China Based on a Complete Decomposition Model
基于完全分解模型的中国万元GDP 用水量变动及因素分析

Water use amount per ten thousand Yuan GDP is an important macro criterion for water resources. Our goal is to lower it at the next stage. It is necessary to fully understand change characteristics and influencing factors of China's water use amount per ten thousand Yuan GDP to achieve the goal. The total change in water use amount per ten thousand Yuan GDP should be decomposed to separate out effects of each factor on it. Based on the Laspeyres index and complete decomposition theory, a complete decomposition model of water use amount per ten thousand Yuan GDP was built. Variations and factors of water use amount per ten thousand Yuan GDP for the primary, secondary, and tertiary industries in 31 provinces, autonomous regions, and municipalities for the period 1997-2009 were analyzed from the perspective of industry and region. Results show that: 1) there was a significant decrease in water use amount per ten thousand Yuan GDP in China between 1997 and 2009. 2) It is the primary factor of water use amount per ten thousand Yuan GDP of China that an improvement in water use efficiency of all industries and regions caused by technological advancement has been made. At industrial levels, the main contribution was made by that improvement in efficiency at regional levels made by the primary and tertiary industries and east, middle, and west China was remarkable. 3) At industrial levels, the structure change in the tertiary industry was also the important reason for lowering water use amount per ten thousand Yuan GDP. 4) At regional levels, compared with the prominent contribution made by the improvement in efficiency, the effect was not noteworthy that the magnitude of the regional structure change was relatively small. But the contribution rate made by regional structure change between 2007 and 2009 cannot be negligible. The reason is that in west and middle areas where water use amount per ten thousand Yuan GDP is relatively high, the ratio of economy is increasing. But at the same time in east areas where water use amount per ten thousand Yuan GDP is relatively low, the ratio of economy has begun to decline. This demonstrates that reasonable use of water resources may be ignored during the process of regional structure changes in recent years. Consequently, evolution and popularization of water-saving techniques serve as an essential approach to boosting industrial and regional water utilization efficiency and reducing water use amount per ten thousand Yuan GDP.