The influence of water resources on population distribution: Driving paths and empirical evidence from China.

Despite long-standing policy efforts to align population distribution with water availability, the mechanisms linking water resources to population patterns remain poorly understood. Existing studies largely emphasize climatic shocks or assume a positive water-population relationship, leaving the structural drivers of misalignment underexplored. This study addresses this gap by developing an analytical framework that elucidates how water resources influence population distribution through ecological, economic, and environmental paths, grounded in the functional roles of water resources and push-pull theory. Using panel data from 271 prefectures between 2012 and 2021, we assess water-population coordination with Lorenz curve and Gini coefficient and identify causal mechanisms through econometric and path analyses. The results reveal a persistent and counterintuitive negative association between water resource availability and population density, with no evidence of convergence over time. This relationship is driven primarily by ecological and environmental paths, while the economic path is insignificant. Notably, these paths converge in a "dual reduction" mechanism whereby greater water endowment expands green space and reduces wastewater discharge, both contributing to lower population density. These findings challenge the conventional carrying-capacity logic that treats water abundance as a demographic advantage and instead highlight water's role in ecological upgrading and structural transformation. Methodologically, this study advances the literature by integrating a multi-path mechanism framework, while theoretically it reconceptualizes the water-population nexus beyond simple hydrological determinism. The results suggest the need to reassess the "Determining Population on Water" approach and to prioritize ecological and environmental paths, especially green space expansion and wastewater reduction, to improve water-population coordination in water-scarce regions.