The Coupling and Spatial-Temporal Evolution of High-Quality Development and Ecological Security in the Middle Route of South-to-North Water Diversion Project

The South-to-North Water Diversion Project constitutes a fundamental initiative designed to enhance water resource distribution and foster regional coordinated development. To investigate the coupling coordination and its spatiotemporal evolution between high-quality development and ecological security (HQD-ES) within the project’s water source areas, this research established a dedicated evaluation index system. Employing coupling coordination, spatial autocorrelation, and Geographically Weighted Regression (GWR) models, the study analyzed the coupled coordination state and its spatiotemporal characteristics across these water source areas for the period 2010–2023. The findings demonstrated that (1) the high-quality development trend remained generally positive, rising from 0.253 to 0.377; ecological safety level showed sustained improvement, increasing from 0.365 to 0.731. (2) The coupling degree (CD) was in a high coupling stage on the whole; the coupling coordination degree (CCD) increased significantly, from imminent imbalance to good coordination state, and the space pattern showed “prominent in the middle and stable in the north and south”. (3) There was no obvious spatial correlation existing between the CCD of HQD-ES in Nanyang City. Tongba, Fangcheng, and Xinye displayed spatial correlation characteristics of low-high aggregation and high-low aggregation. GWR results showed that industrial structure, urbanization, and greening level promoted CCD, while economic level, population density, and environmental regulation inhibited it.