Abstract
Rivers worldwide are facing an escalating risk of devastating floods driven by climate change, despite the extensive regulation of human infrastructures. Previous large-scale analyses of floods have reconstructed global and regional patterns by accounting for reservoir regulation; however, the critical role of levees remains largely ignored. Here, we provide a timely assessment of infrastructure-driven flood dynamics by simulating the joint influence of dams and levees across the Yangtze River Basin during 1980–2019 using the CaMa-Flood model. Results clarify the distinct and complementary roles of these structures: levees rectify peak-flow fidelity (median Nash–Sutcliffe Efficiency 0.62 at 32 validated flow stations) while dams primarily enhance low-flow accuracy (median logNSE 0.71). Ignoring levees results in a ~ 15% overestimation of annual maximum inundation area relative to dam-only assessments. Despite parameterization uncertainties, this study provides the first insights highlighting the critical role of integrating levees to accurately simulate regulated river systems and flood risk assessments.