The effect of social economy-water resources-water environment coupling system on water consumption and pollution emission based on input-output analysis in Changchun city, China

With the rapid development of social economy, water resources consumed excessively and water pollution emissions increased. However, few studies have considered the feedback of water resources and water environment on social economy. In this study, a social economy-water resources-water environment coupling system was constructed by multiple regression model and system dynamic model. Five scenarios were set to investigate the relationship among industrial restructuring, pollution treatment and water conservation in Changchun city, China. Based on input-output model, this study analyzed the effect of the coupling system on the economic efficiency of sectoral water consumption and pollution emission. The driving factors were identified and the contributions were quantified using structural decomposition analysis model. The results showed that pollution treatment and water conservation promoted economic development and increased Gross Domestic Product (GDP) by 36.76%. The comprehensive effect of industrial restructuring, pollution treatment and water conservation was better than single measures, which made the GDP increment (44.39%), Chemical Oxygen Demand (COD) reduction (34.11%), Ammonia Nitrogen (NH3-N) reduction (52.50%) and total water consumption increment (7.56%) largest. Meanwhile, the comprehensive effect improved the water consumption efficiency of agriculture and service industries, reduced indirect water consumption in industrial sectors, and improved the economic benefits of pollution emissions in all sectors. The industrial restructuring further increased the contribution of population to COD emissions and the contribution of emission intensity to NH3-N emissions. Under the condition of comprehensive effect, the final demand level was the main factor for the increase of COD and NH3-N, contributing 36998.80 t and 821.07 t, respectively. Therefore, the government should pay attention to saving water resources and protecting water environment while developing social economy. The study quantified the coupling relationship between social economy, water resources and water environment, and provided guidance for water resources management in sectors.