Regionalization of water environmental carrying capacity for supporting the sustainable water resources management and development in China

With the rapid economic growth and social development in China, conflicts over water resources between human and nature are continuously increasing which is attracting the attention of researchers. At the same time, discharge of water pollutants and exploitation of water resources pose a daunting challenge to the sustainable development of economy and society. China consists of 34 provincial administrative regions having similar or different characteristics in the levels of economic development, water resource endowment, water environmental capacity and water environmental pressure. Among these, it is meaningful to analyze spatial similarities and variations in water environmental carrying capacity (WECC), which contributes to carrying out different and scientific strategies for the management of water environment and for sustainable economic and social development in China. An index system is established to quantify WECC from the perspectives of carrying capacity, environmental pressure, vulnerability of water environment and exploitation and utilization potential. The k means clustering method is applied to conduct the similarity combination based on the quantification of 4 integrated indicators using catastrophe progression method. The silhouette coefficient is introduced to measure the quality of clustering and to determine the optimal clustering number. The obtained results indicate that carrying condition of water environment becomes more and more better and exploitation and utilization potential of WECC is decreasing gradually from the east to the west in China, and there are more overload in the north provinces and less in the south. In addition, water environmental vulnerability in the west is higher than that of central and eastern provinces in China. The optimal clustering number is 4 obtained by calculating the silhouette coefficient. Also, 31 provinces are categorized into 4 sub-areas i.e. key protected area, controlled development area, optimized development area and prioritized development area. The suggestions on the corresponding bidirectional regulation to different sub-areas are also put forward to provide a scientific reference to rational distribution of economic development, elaborate management of water environment as well as regional sustainable development in the future.