Abstract:

River system connectivity (RSC) is closely related with water security issues, including water resources allocation, flood and drought management, and the protection and restoration of aquatic ecosystems. Currently, there is a lack of comprehensive studies evaluating RSC at a national level, and few comparisons were conducted among different water resource zones. To address this gap, an RSC evaluation system is established by employing hierarchical analysis and the entropy weight method. The evaluation indices reflect the quantitative, structural, and hydraulic characteristics in line with the fundamental connotation of RSC. The spatial distribution map of RSC values on different scales (first-grade and third-grade national water resource zoning) is plotted. Results indicate that RSC values decline progressively from southeastern to northwestern China, categorizing into low (0.07-0.38), medium (0.39-0.50), and high (0.51-0.78) levels. Low RSC values primarily occur in the arid inland areas of northwest China, while medium values are found in hilly regions, and high values are concentrated in the plain river networks of the middle and lower reaches of the Yangtze and Huaihe River basins. This study contributes to enhancing RSC planning and development at both regional and catchment scales.

Key words: river system connectivity, evaluation system of river system connectivity, scales of water resource zones, China, hydraulic characteristics