Evaluating River Network Resilience through Topological Analysis Using a Complex Network Approach

Abstract River network systems (RNS) comprise numerous interconnected rivers whose topological structure governs flow dynamics, thereby playing a central role in material transport, and ecological processes, and overall system resilience. Intensive human activities, particularly the widespread construction of hydraulic infrastructure, have profoundly altered river network topology, reshaping hydrodynamic processes and affecting resilience functions. However, few studies quantitatively examine how topological variations affect resilience and identify most critical topology components. To address this gap, we developed an integrated assessment framework that couples complex network theory with hydrodynamic simulations to quantify the interrelationships among network topology, hydrodynamic behavior, and resilience. Eight topological metrics derived from complex network theory were employed to evaluate network connectivity and robustness, and four hydrodynamics-based resilience indicators were proposed to characterize system resistance, absorptive capacity, and recovery ability. Two types of river systems were analyzed: an idealized reticular network with fewer boundaries, and a real-world river network with multiple boundaries conditions. The results show that among the eight topological metrics, algebraic connectivity, network efficiency, and average shortest path length exert the strongest influence on system resilience, as these indicators partially capture the characteristics of flow pathways. Regarding resilience indicators, the maximum water level rise rate showed only a weak correlation with topological metrics, as it was primarily influenced by a single local river reach. In contrast, the maximum water level drop rate exhibited a strong correlation, being more strongly governed by the overall dynamic processes of the river network and thus accurately representing system resilience. Integrated network centrality analysis identified critical river reaches that act as structural bridges, sustaining connectivity and resilience across the system. In addition to high-centrality reaches, boundary reaches were also found to be crucial, particularly in networks with fewer boundaries. This study advances the understanding of how river network topology regulates resilience and provides valuable insights for river management and the strategic planning of hydraulic infrastructure.