Structural Connectivity Analysis and Optimization of the River Network in the Baiyangdian Basin Using Complex Network Theory and MCR

The morphological structure and connectivity of river systems are critical to ecological functions, water resource allocation, and disaster prevention in watersheds. This study applies an integrated approach combining morphological analysis, graph theory, landscape ecology, and complex network theory to analyze and optimize the river network structure of the Baiyangdian basin. The results showed significant structural improvements from 2014 to 2025: river network density ( Dr ) increased from 0.0335 to 0.1443 km/km 2 , and river frequency ( Fr ) rose from 0.0015 to 0.0132 rivers/km 2 . Connectivity indices also exhibited an overall increasing trend: circuitry ( α ) increased from −0.05 to 0.03, the edge–node ratio ( β ) from 0.90 to 1.06, and network connectivity ( γ ) from 0.30 to 0.35. Spatial analysis further identified a clear gradient of node importance: peripheral nodes showed low centrality, while critical nodes were predominantly concentrated along the South-to-North Water Diversion Project (SNWD) corridor. Optimization based on the 2025 baseline further improved network connectivity, with corresponding increases in connectivity metrics. These findings provide scientific support for integrated water management and climate-adaptive planning in the Baiyangdian basin.