Water system connectivity and urban development coordination in the Pearl River Delta urban agglomeration

Under the double pressure of global climate change and rapid urbanization, river system connectivity becomes a critical factor for regional water security and urban sustainable development． In this study high-resolution remote sensing imagery was used to extract water body data in the highly urbanized Pearl River Delta． A comprehensive assessment system is constructed for river connectivity, covering both structural and functional aspects (river network density, water surface ratio, circuitry, and node connectivity)． Urban development indicators are incorporated and analytic hierarchy process-entropy weight method (AHP-EWM) is used to determine weights． Coupling coordination degree model (CCDM) is used to quantitatively evaluate interaction between river system connectivity and urban development in the region for 2024． Significant spatial variations are found in connectivity, with Foshan, Zhuhai, and Dongguan exhibiting structural advantages． Urban development is found to follow a “dual-core pattern led by Guangzhou and Shenzhen”, aligning with their economic levels． Coupling coordination analysis indicates that cities like Guangzhou, Foshan, and Dongguan are at an “intermediate coordination” stage, while peripheral cities Jiangmen, Zhaoqing, and Huizhou are in an “imbalanced decline” state． In this research we find the intrinsic feedback mechanisms between river systems and urban functions in rapidly urbanizing areas; this provides scientific support for spatial planning, water ecological security, and harmonious human-water development in the Pearl River Delta．