Spatiotemporal urban-water interactions in upper Min River settlements within a triaxial framework

The upper Min River basin in southwest China serves as a representative region for studying urban-water interactions. Focusing on Songpan, Taoping, Shuimo, and Guanxian, this study establishes an X–Y–Z triaxial framework of temporal evolution, spatial hierarchy, and functional mechanism to reconstruct interaction trajectories, analyze contemporary perceptions, and extract spatiotemporal synergistic mechanisms. The main findings are as follows: (1) Settlements exhibit structural continuity yet differentiated development logic—from headwater frontiers to the outlet plain—driven by the differential coupling of the three axes. (2) Contemporary perceptions vary significantly between social groups, revealing challenges such as cultural dilution, commercial encroachment, and a disconnect from traditional water-culture expressions. (3) Evolutionary pathways are shaped by the shifting influence of natural constraints, trade-transport networks, and institutional-cultural embedding. This study offers a transferable methodological paradigm for the governance and sustainable development of urban-water heritage in mountainous watersheds globally.