Disentangling Climate and Anthropogenic Impacts on water resources in the Haihe River Basin using a coupled surface–subsurface model

The Haihe River Basin in northern China is one of the most water-stressed regions characterized by limited natural water resources, intensive groundwater exploitation, and a water use structure dominated by agricultural irrigation. In recent years, partial groundwater recovery has been observed in some areas, driven by large-scale water diversion projects, groundwater abstraction control policies, improved irrigation efficiency, and favorable climatic conditions. However, whether this recovery represents a sustainable transition or a temporary, human-regulated phenomenon under climate variability remains unclear.In this study, we employ a coupled surface–subsurface hydrological model (CWatM–MODFLOW) to quantify the combined impacts of climate change and human water use on basin-scale water resources. The model explicitly represents surface water–groundwater interactions and dynamically simulates irrigation water demand and other sectoral water withdrawals within the hydrological system.Model simulations with multiple future climate scenarios are conducted to investigate potential changes in water availability, water demand, and their combined effects on the spatial and temporal patterns of water stress across the basin. By jointly analyzing projected water resources and irrigation-dominated water consumption, this study aims to disentangle the relative contributions of climate forcing and anthropogenic activities to future water scarcity and groundwater sustainability in the Haihe River Basin.The outcomes of this work are expected to improve understanding of how climate change and human water use may influence water availability and stress patterns in the Haihe River Basin.