A new study published in the journal Engineering introduces an integrated model designed to evaluate flood risks to both life and property in the lower Yellow River (LYR). This region is one of the most densely populated floodplains, and with climate change amplifying the frequency and severity of floods, understanding and managing these risks has become increasingly critical. The refined methodology and comprehensive approach established in this research offer a promising horizon for better floodplain management and disaster preparedness in vulnerable zones.
River flooding has emerged as a dire global challenge, leading to severe economic losses and posing threats to human lives. The lower Yellow River is no exception, characterized by its intricate channel-floodplain system and heavy sediment load, which complicates the assessment of flood risks. Traditional two-dimensional (2D) morphodynamic models typically struggle to accurately simulate the dynamics of these sediment-laden floods, creating a gap between available methodologies and the specific needs of this geographic region. Previous evaluations of flood risks have tended to be too simplistic, often omitting key variables and insights that are crucial for accurate analysis.
Addressing these challenges, the research team constructed an innovative integrated model composed of two distinct modules. The first module is a 2D morphodynamic model that incorporates modified hydrodynamic governing equations specifically tailored to deal with sediment-laden flows and account for the deformation of riverbeds. The advanced modeling utilized the finite volume method on unstructured meshes, a technique that increases computational efficiency and accuracy while capturing the complex interactions between water and sediment.
The second module of the integrated model is dedicated to evaluating flood risk from multiple perspectives—specifically focusing on human lives, buildings, and agricultural yield within the floodplains. For instance, the flood hazard degree for people is assessed through an improved formula that takes into consideration factors such as body buoyancy and flow velocity. Meanwhile, the evaluations for buildings and crops rely on a combination of mechanical analyses and thorough field surveys, culminating in a comprehensive view of the potential impacts of flooding.
To validate the efficacy of this integrated model, researchers executed simulations based on two historical flood events in the lower Yellow River: the hyperconcentrated flood of 2004 and the dike-breach flood that occurred in 2003. The results from the 2004 simulation demonstrated strong predictive validity, with the model’s projections of sediment concentration exhibiting a maximum underestimation of only nine percent. This reliability continued with the dike-breach flood simulation, where the model’s predictions of inundation depth closely matched field data, underscoring its potential for practical applications in real-world scenarios.
Armed with validated models, the research team proceeded to assess flood risks under three predominant floodplain management schemes. The first scenario retained the existing management practices, referred to as Scheme I. The second scenario involved the construction of protection embankments dubbed Scheme II, while the third scenario, Scheme III, entailed a strategic partitioning of the floodplain. Through this analysis, the researchers identified a particularly vulnerable reach between Jiahetan (JHT) and Gaocun (GC) under a 1000-year return period extreme flood.
The findings from this assessment revealed significant differences in inundation degrees across the outlined management schemes. Under the original Scheme I, the majority of floodplains experienced medium and heavy inundation levels, exposing both residents and infrastructure to considerable risk. In contrast, the implementation of Scheme II significantly mitigated the extent of inundation, shifting more regions towards light inundation levels and showing a notable improvement in flood risk mitigation.
Among the three management options, Scheme III resulted in a mix of inundation levels, though it too provided substantial benefits, with a marked reduction in high-risk areas for human life and property. Notably, the high-risk zones were found to diminish by 21% to 49% under Scheme II and by 35% to 93% under Scheme III compared to the original Scheme I, indicating the effectiveness of strategic floodplain management practices.
While this study establishes a robust framework for assessing flood risks, it is essential to acknowledge the limitations. The authors clarify that the integrated model does not fully encapsulate all socio-economic factors, such as infrastructure support and precise costs. However, it serves as a critical starting point for additional research efforts and decision-making processes in the evolving landscape of floodplain management.
In conclusion, the integrated model presented in this study symbolizes an essential advancement in the comprehensive evaluation of flood risks associated with the lower Yellow River. This research not only enhances foundational knowledge in hydraulic engineering and civil engineering but also provides vital insights that could shape policy and practice for floodplain management in the face of climate change. The potential implications for disaster risk reduction and community resilience could be transformative, offering a beacon of hope for heavily populated flood-prone areas across the globe.
Subject of Research: Integrated flood risk assessment model for the lower Yellow River
Article Title: Modelling of Flood Risks to People’s Life and Property in the Lower Yellow River Under Different Floodplain Management Modes
News Publication Date: 26-Feb-2025
Web References: https://www.sciencedirect.com/journal/engineering
References: Cheng, Y., Xia, J., Fang, H., Zhou, M., Zhou, Z., Lu, J., Li, D., Falconer, R. A., Bai, Y. (2025). Full text available at Engineering. DOI: 10.1016/j.eng.2025.02.011
Image Credits: Not provided
Keywords
Flood risk assessment, Yellow River, integrated model, climate change, floodplain management, morphodynamic modeling, disaster preparedness, hydraulic engineering.
