Comprehensive assessment of water supply-demand imbalance impacts in Henan's Yellow River water-supply area under the extreme hydrological drought scenario

Extreme hydrological drought exacerbates water supply-demand imbalances, especially in water-scarce river basins. Therefore, assessing the impacts of such imbalances in the context of extreme hydrological drought is crucial. This study develops a three-dimensional social-economic-ecological assessment framework to evaluate these impacts under an extreme hydrological drought scenario, incorporating indicators of social impact deviation, expected economic loss, and emergy-based ecological value loss. On this basis, a composite impact index is constructed using a relative-entropy-based combination weighting method. The Henan Yellow River water-supply area in China is selected as a case study to evaluate the impacts under this scenario. The results show that high-impact cities are clustered along the Yellow River's main stem, forming a continuous high-value belt. The ecological dimension contributes slightly more to the overall impacts than the social and economic dimensions. High-impact cities show both high economic and ecological value losses, whereas moderate-impact cities are typically dominated by a single dimension. As drought severity increases from moderate to extreme hydrological drought, the composite impact index generally increases across the study area. The comprehensive impacts are shaped by regional water resources, industrial structure, water allocation, and water-use structure. The findings provide quantitative support for zoned regulation of water supply-demand imbalance risks.