Water security of the megacities in the Yangtze River basin: Comparative assessment and policy implications

Abstract

Abstract Having intensive economic development and rapid urbanization, the Yangtze River basin, namely the heart of China’s prosperity, has faced challenges in the accompanying deterioration of water security. How to closely inspect the features and development of water security for the major cities in the basin and to compare the water security conditions between the major cities at the basin scope is a keystone to better support water management practice in the cities as well as regions. Hence, this study refined the previous framework by applying 19 indicators to describe the conditions of resource, infrastructure, waterway, efficiency, risk, and capacity and then integrated the data-driven weighting approach, the Criteria Importance Through Inter-criteria Correlation (CRITIC) method, to objectively evaluate the development and characteristics of water security of the megacities in the Yangtze River basin, i.e., Shanghai, Nanjing, Wuhan, Chongqing, and Chengdu, during 2011–2017. Based on the aggregated scores, Chongqing had the best overall water security condition (0.696) in 2017, followed by Chengdu (0.613), Shanghai (0.581), Nanjing (0.496), and Wuhan (0.471). During 2011–2017, Chongqing and Shanghai had a greater improvement in the water security condition, while Wuhan had the least. From a basin perspective, the upstream megacities had the advantage of their water availability and depletion conditions, river quality, pollutant discharge, government’s support of water affairs, and the societal investment in water conservancy. On the other hand, the middle- and downstream megacities had shown the better performance of the water affordability, the density of the sewage network, and water intensity. The sensitivity analysis detected the average of the standard variations of the score changes as 2.03% in the context of different indicator sets and thus assured the outcome robustness. This study enhances the assessment frameworks, facilitates the applications of temporal and spatial comparative evaluation of water security conditions on city and river basin level, and identifies the policy gaps for enhancing water management in the magacities and the basins.