Does urbanization intensify regional water scarcity? Evidence and implications from a megaregion of China

Abstract Water scarcity as a serious global issue has been challenging the human beings. Despite broad research on water scarcity from global to local scale, there is lack of comprehensive understanding of water scarcity in urban areas, particular in the megaregion which is a cluster of a number of cities with dense human activities and close interactions between each other cities. In this study, we took one important megaregions of China, the Beijing-Tianjin-Hebei (BTH) megaregion, as a case study to analyze the spatial-temporal trajectories of water scarcity and the driving forces. First, we developed a new water scarcity index system that could separately assess the spatial variation of physically- and human-induced water scarcity. Second, we explored the relations between water scarcity and the multi-manifestation of urbanization in terms of demographic, social, landscape, and economic aspects. The results showed: 1) the overall water scarcity varied spatially and temporally across different cities in the BTH megaregion; the physically- and human-induced water scarcity was not spatially coincident; most the variation in water scarcity was due to human-induced water scarcity; 2) urbanization primarily affected the human-induced water scarcity; the economic urbanization had the strongest negative impacts, whereas the landscape urbanization had positive effects; non-urban water utilization, such as agricultural water use, strongly competed for water use with regional urbanization. Overall, the results highlight the importance of optimizing economic development mode and controlling agriculture water use to alleviate the water scarcity of megaregion. The general framework used in this study can be applied to other megaregions in China and to some other developing countries that have similar water scarcity problems.