Coupling Relationship between River Network and Land Use in the Erhai Lake Basin based on FGTWR-CCD

Purpose This paper aimed to reveal the structural characteristics and coordinated evolution mechanisms of the coupling relationship between the water network and land-use system in the Erhai Lake Basin.

Methods Taking the Erhai Lake Basin as the study area, a fusion of GeoDetector and geographically and temporally weighted regression (FGTWR) analytical framework was established to identify the key factor combinations and assess the coupling coordination degree (CCD) and its spatiotemporal differentiation.

Results From 2001 to 2023, the CCD between the river network and land use had shown an overall increasing trend. The dominant coordination types shifted from basic coordination and moderate discoordination to primarily moderate coordination, with some areas reaching high coordination. The spatial pattern was characterized by a “higher-in-the-south, stronger-in-the-west” distribution. The coordination network density increased overall, exhibiting a progressive “upstream-midstream-downstream” increasing gradient. The network morphology evolved from a single linear structure along the Luoshijiang-Yonganjiang corridor to a complex reticular system with multiple nodes and channels, reflecting increasingly close linkages among counties. The spatiotemporal differences in the CCD were primarily driven by factor-combination effects. A positive synergistic effect occurred in the southern Boluojiang area and the western lakeshore belt when river length and connectivity were well matched with the spatial configuration of construction land and ecological land; in contrast, persistent negative impacts were observed in the northern “Three Rivers” area and the eastern sector where river-network density was high but ecological-land continuity and canal-system connectivity were insufficient.

Conclusion Pronounced water-land spatial differentiation exists in the Erhai Lake Basin. In low-coordination areas, ecological-land continuity and canal-system connectivity should be enhanced; in high-coordination areas, river-network connectivity and an intensive land-use pattern should be consolidated to strengthen integrated watershed governance and improve the effectiveness of water-environment regulation.