Table 1_Spatial evaluation and enhancement of forest water supply ecosystem service scoring using water-source-based flow path analysis.docx

This study empirically evaluates whether the conventional Water Supply Ecosystem Service (ES) assessment framework in South Korea adequately reflects actual water supply processes, and proposes a methodological framework for its improvement. Using the nationwide distribution of water sources, we divided the study area into three regions and inferred potential groundwater contribution pathways (flow paths) through terrain-based analysis. A sensitivity analysis identified a 500 m grid as the optimal resolution, and a grid-based scoring approach was applied to compare the conventional and enhanced ES frameworks. The results indicate that the conventional scores broadly correspond to regional patterns of water source distribution, suggesting partial representation of potential water supply capacity. However, flow-path-based evaluation revealed that scores along inferred supply pathways were not consistently concentrated in the higher range of the overall distribution, highlighting limitations in capturing actual supply processes. In contrast, the enhanced framework, incorporating hydrologically relevant indicators such as soil properties, topographic conditions, and slope morphology, significantly improved the percentile ranks of flow-path grids, with regionally varying effects. By evaluating and refining Water Supply ES assessments using actual water source locations rather than watershed-scale proxies, this study provides a process-oriented framework for more realistic evaluation and management of forest-based water supply ES.