Exploring the underlying mechanisms of spatial blue water consumption inequality in Chinese complex topographic...

Understanding the spatial inequality of blue water consumption (BWC) is essential for promoting sustainable and equitable water utilization, especially in topographically complex regions. This study constructed an integrated analysis framework to examine multi-dimensional spatial blue water consumption inequality (BWCI) based on the Gini coefficient, inequality decomposition techniques, disparity index (DI), and Partial Least Squares Structural Equation Model (PLS-SEM). The Step Transition Zone of Northwest China (STZNC) is employed as a case study, and its overall level, sources and driving factors, inequality types, and the underlying inducing mechanisms of spatial BWCI were investigated. The results revealed a worsening trend and significant dimensional heterogeneity in BWCI in the STZNC, with average Gini coefficients of 0.73, 0.42, and 0.37 between BWC and water endowment, economy, and population, respectively. Agricultural BWC exacerbated the total BWCI, as its contribution to inequality regarding population and economy (83.6 % and 87.2 %) is higher than its proportion of BWC (70 %), while altitude-based intergroup disparities are the primary sources of inequality. Spatially, regional BWCI types exhibited altitude dependence but may be locally reversed due to abnormal socio-economic and water resource conditions within the same altitude zone. Mechanistically, spatial BWCI in the STZNC was shaped by altitude-driven coupling of natural constraints and socioeconomic factors. Altitude largely determines regional water endowment and socioeconomic scale, coupled with disparities in water consumption efficiency across regions, jointly introduce spatial inequality patterns along the altitude gradient. This study provides valuable insights for mitigating spatial water inequality and enhancing sustainable water resource management in complex topographic regions.