Green efficiency of water resources in Northwest China: Spatial-temporal heterogeneity and convergence trends

Green efficiency of water resources (WGE) is the basis for developing cleaner production and implementing sustainable development. This study deconstructs WGE into the components of green efficiency identified as agricultural water (AGE), industrial water (IGE), domestic service water (SGE), and ecological water (EGE), then analyzes the dynamic change trend, spatial-temporal evolution characteristics and spatial convergence of identified WGE in Northwest China utilizing the Super-SBM model, spatial convergence model together with an exploration spatial data analysis. The results show that the average of SGE and its average annual growth after 2007 are the highest; Not only do AGE, IGE, SGE, and EGE have obvious spatial-temporal heterogeneity, they will eventually converge into one steady-state growth trajectory at different rates (about 3.8, 3.30, 3.25 and 3.20), which are related to the level of economic development, population size, industrial structure, government expenditure and spatial spillover effects from joining or adjacent areas. In addition to selectively improving some external conditions to promote the path of steady growth of water resources, local governments in Northwest China can also explore the construction of cooperative management and restriction mechanisms on crossregional water resources to build a "destiny community" for WGE.