Quantifying water provision service supply, demand and spatial flow for land use optimization: A case study in the YanHe watershed

The explicit quantification and spatial mapping of the ecosystem service (ES) supply and demand associated with land use changes can provide relevant insights for enhancing land management. However, few advancements and efforts have been applied to science policy processes and land management optimization because most studies to date neglected the supply-demand coupling mechanism. This paper considers the YanHe watershed to propose a comprehensive framework quantifying the supply, demand and spatial flow of the water provision service associated with land use changes. The results showed that land use changes had important effects on both the supply side and the demand side of the water provision service. The water provision service has significant spatial mismatches between water supply and water demand. A high water supply occurred in the upper and lower reaches, while a high water demand was distributed in the urban districts. We mapped and determined the spatial flow process of the water provision service now and in the future. The results highlight the need to fully understand the importance of service flow for improving the water security patterns of benefiting areas. This study provides a scientific basis for watershed policymakers to optimize land management and reduce water deficits and mismatches.