From salt to silicon: industrial evolution and freshwater dependence on China’s Daishan Island

IntroductionRapid economic intensification poses a significant threat to freshwater security on small islands. This study examines how industrial structural change impacts freshwater use and pollution in Daishan Island, Zhoushan City, China, and explores the co-evolution of freshwater systems with socioeconomic–ecological dimensions to inform sustainable development strategies for small islands.MethodsUsing standardized socioeconomic, environmental, and freshwater datasets from 2010 to 2019, we applied information entropy analysis and principal component regression to quantify the effects of industrial evolution on freshwater resources.ResultsThe results indicate an overall upward trend in the coordination between freshwater use efficiency and socioeconomic development. However, industrial structural evolution significantly influences water pollution levels.DiscussionThese findings provide a theoretical basis for optimizing freshwater allocation and utilization, and clarify the mechanisms through which industrial evolution impacts freshwater resources on small islands, offering valuable insights for sustainable development policy in similar small island contexts.