Journal of Flood Risk Management最新文献

The increasing frequency of urban flooding due to climate-induced extreme rainfall highlights the critical need for adaptive emergency preparedness. Maintaining public access to essential services during such events is critical, yet flood risks to the transport network can compromise public safety and mobility. This study employed a combined depth-velocity stability function to assess the risks posed to individuals navigating floodwaters and evaluates accessibility to key service points using basic risk-avoidance criterion. Transport network analysis compares the no-flood, depth-only and depth-velocity risk scenarios. Analysis indicates that risk assessments solely based on flood depth significantly underestimate localised risk in urban environments. At the flood peak, high-risk areas for vehicles and pedestrians are underestimated by 18.2% and 83.3%, respectively, while these increase to 36.4% and 240.0% for medium-risk areas. Applying depth-velocity thresholds determined the obstructed roads and inaccessible zones. Risk-adjusted alternative routes were generated considering the obstructions, providing viable paths for the public to use during the flood peak. The integrated approach, combining flood modelling, stability functions and network analysis offers a framework that can significantly contribute to the improvement of risk resilience and transport management for flood-prone cities.

Flooding is among the most devastating natural catastrophes affecting human life and property. Climate change and environmental degradation have exacerbated flooding disasters. Developing countries experience greater damage from flooding due to their low resilience, limited financial resources, weak early warning systems, and technological limitations. Accurate data, prediction, delineation of vulnerable areas, and formulation of local action plans can help minimize the extent of economic losses and fatalities due to flooding. In the current study area, limited data are available to lessen flood potential risks. Remote sensing and GIS approaches were adopted for mapping potential flood-susceptible areas. Topographical, hydrological, and spectral indices conditioning factors were integrated, and a weighted overlay analysis was performed in ArcGIS. The results revealed that about 8.73%, 77.16%, and 14.08% of the study region are categorized as susceptible, moderately susceptible, and less susceptible to flooding, respectively. The findings would help government authorities and relevant bodies in developing early warning systems, advancing technology, creating local action plans, and formulating flood hazard mitigation and adaptation strategies.

The position of bridge piers relative to abutments plays a critical role in controlling large wood (LW) accumulation and the resulting local scour, which are among the leading causes of bridge instability. Previous studies have mainly examined isolated piers or abutments using simplified, solid debris shapes, overlooking the interactive effects of pier–to–abutment distance, and the natural porosity of wood accumulations. To address this gap, a comprehensive series of flume experiments was conducted, systematically varying pier–to–abutment distance, log length, flow intensity ratio, bed condition (fixed, movable-static, movable-dynamic), and temporal evolution of scour. The results show that LW accumulation probability (LW AP) is primarily controlled by relative log length, bed mobility, and pier–to-abutment distance. Accumulation reached up to 98% for longer logs at large pier–abutment distances, as these positions aligned the piers with the main LW transport path. While flow intensity ratio and pier placement significantly influenced scour depth and geometry, porous, and transient LW accumulations produced only minor additional scour effects (< 6.5%) compared to solid accumulations reported in earlier studies. This study, by highlighting pier–to–abutment distance as a governing factor in LW accumulation and scour, simulating realistic LW with variable porosity instead of idealized debris shapes, and comparing LW AP under fixed, static, and dynamic bed conditions, provides novel insights into flow–structure–wood interactions and demonstrates that strategic pier placement can offer more effective risk mitigation than conservative design assumptions based on non-representative debris models.

The study prioritizes sub-watersheds (SWs) from the Taleqan Watershed in Iran based on Flood Generation Potential (FGP) using Multi-Criteria Decision Making (MCDM) approaches, including Condorcet, Borda scoring, Fallback bargaining algorithms (Game Theory [GT]), and Best-Worst Method (BWM), and compares the results with observed discharge data. Based on a review of reliable resources, 30 geo-environmental criteria were identified to prioritize FGP. Quantitative values for each criterion were then calculated for all SWs. The Principal Component Analysis (PCA) was employed to reduce the FGP conditioning criteria. Next, using the decision matrix based on the selected criteria, three GT algorithms and BWM were applied, and the SWs were prioritized accordingly. FGP maps were then created using all four approaches, with results categorized into five classes, namely, very low, low, moderate, high, and very high. Finally, the prioritization patterns from the MCDM approaches were compared against observed discharge data from all 18 SWs to select the optimal method. The results from all four MCDM approaches indicated that SW5 had the highest potential for flood generation. The BWM approach classified about 56% of the study watershed as having low or very low FGP. In contrast, GT identified only 45% of the area in this category, with approximately 39% of SWs classified with high or very high FGP. The comparison of means using the One-Way ANOVA test revealed insignificant differences between the MCDM approaches and the observed discharge data. However, the similarities between the results of the Condorcet, Borda scoring, Fallback bargaining, and BWM approaches, compared with the observed discharge data, were 27.78%, 27.78%, 33.33%, and 44.44%, respectively. Accordingly, the BWM approach with the highest similarity was chosen as the optimal model. The summary indicated that the BWM approach outperformed the GT algorithms in mapping flood generation compared to the observed flood discharge data.

Urban flooding is a major socio-economic challenge in many cities of the Global South. Inadequate and unequal urban planning often excludes the poor majority, while rapid urban change makes it difficult to obtain reliable, up-to-date data for flood management. This study investigates changes in the river channel and informal settlements along the Msimbazi River in Dar es Salaam, one of the world's fastest-growing cities, which faces increasingly severe annual flooding. We use high-resolution satellite imagery, open elevation data, and a relative elevation model approach to map flood-prone areas and analyze flood-induced transformations between 2013 and 2022. Our findings show that even a small change in the Msimbazi River's water level leads to significant shifts in flood zones, with risk areas evolving during each flood event. During the study period, flooding also triggered substantial geomorphological changes in areas not included in existing flood risk maps. These changes would have remained undetected without high-resolution imagery or field investigations. Informal settlements underwent considerable spatial shifts following floods, disproportionately affecting the most vulnerable populations. Informal settlements were also expanding further away from the city center, where flood risks are primarily geomorphological rather than driven by overbank flooding and thus overlooked in the local flood risk assessments. The results of this study emphasize the need to integrate geomorphological insights and vulnerability indicators into flood risk assessments and to engage civil society in the process. Additionally, they highlight the importance of making high-resolution satellite data widely accessible, ensuring that its benefits extend beyond wealthier groups.

Flooding is a natural calamity that causes widespread devastation, including severe infrastructure destruction, significant economic consequences, and social disturbances around the world, particularly in the Sinai region. Wadi Ked is one of Sinai, Egypt's, most vulnerable districts to flood hazards, and it is the location used for this study. This study aims to create a map of flood-prone areas in Wadi Ked by combining Geographic Information System (GIS) technology and multi-criteria decision-making (MCDM) techniques, utilizing the Analytical Hierarchy Process (AHP) methodology. To achieve the study's goal, flood-related factors such as elevation, slope, distance to roads, distance from streams, annual rainfall, drainage density, topographic wetness index, land use and land cover, normalized difference vegetation index, soil type, and curvature were weighted and overlaid. The results show that 26.91% of the areas studied have a low sensitivity to flooding, whereas roughly 73.09% of the area is moderately to very highly vulnerable to flooding. The study proposed a dam with a height of 30 m, a width of 0.416 km, and a lake capacity of 31.74 million cubic meters (MCM). The surface runoff volumes from 50- and 100-year storms in sub-basins 1–5 are 23.07 MCM and 29.66 MCM, respectively. Model validation was performed by comparing susceptibility maps generated from literature-based and expert-based AHP weights, revealing a 98% spatial agreement and a Kappa coefficient of 0.995, confirming the model's robustness. This study offers value to decision-makers and planners by utilizing morphometric properties and flash flood risk maps to identify suitable locations for dams.

Nature-based solutions, such as temporary storage areas (TSAs), are increasingly implemented within natural flood management strategies to mitigate flooding and soil erosion by attenuating surface runoff during storm events. However, guidance on optimising site-specific TSA designs for runoff attenuation remains limited, and no existing approach comprehensively evaluates TSA effectiveness across multiple flood mitigation metrics. This study addresses these gaps by introducing the TSA Design Optimiser Tool (TSA-DOT), a decision support tool for designing and optimising TSAs as effective nature-based solutions for runoff attenuation, contributing to flood mitigation. The tool evaluates TSA performance using five flood mitigation metrics: storage efficiency index, mean retention time, peak flow attenuation, peak flow reduction, and changes in peak flow travel time. It incorporates site-specific data such as topography and potential storage capacity, soil infiltration rates, and design storm events. Users can prioritise and customise flood mitigation metrics, making the tool suitable for a wide range of catchment settings. When applied at two agricultural TSA sites in northeast Scotland, the tool identified the importance of optimising storage-to-drainage relationships for effective runoff attenuation and highlighted the need for increased storage capacity or drainage adjustments under extreme storm events or limited soil infiltration. TSA-DOT provides practical guidance for using TSAs as part of flood risk management, with integration potential into catchment-scale hydrological models for scalable, site-specific applications.

Natural flood management (NFM) uses natural features and processes to manage flood risk. Although natural processes in river flow are well known, their use to manage floods has been only deeply analyzed since recent years, and the hydraulic behavior and performance of some measures is not yet fully understood. Leaky woody dams (LWD) are one example of the application of NFM, which is very complex to understand, and many uncertainties are still unresolved. In practical applications, the effect of LWD is modeled with different assumptions (Manning's n, geometry changes, porosity, etc.), but none of them represent the real physics of the problem. This paper presents novel lab experiments that attempt to simulate LWD in a river channel. The experiments were developed in a straight research flume. The performance of the LWD in terms of outflow capacity and the effect in terms of increase in water levels upstream and velocities downstream have been analyzed. The orifice + weir model has been proposed as the more realistic model to simulate the flow through LWD, and empirical coefficients of discharge for applications in analytical methods and in numerical models have been obtained. The results help to understand the hydraulic behavior of LWD, and the coefficients of discharge obtained can be useful to reduce uncertainties in numerical modeling for practical applications.

Flood events are the most common weather-related hazard in Europe and Spain, comprising 41% of such events between 2001 and 2020. Mediterranean catchments, with steep slopes and short river courses, are particularly vulnerable to intense convective rainfall, often triggering flash floods. To address this risk, the University of the Balearic Islands developed RiscBal, an innovation ecosystem featuring a high-resolution Multi-Hazard Early Warning System. Its core, RiscBal-Warnings, integrates real-time data from 56 discharge-monitoring stations and 32 rainfall/soil moisture stations, forming the RiscBal-Control network. These stations are positioned in high-risk and historically flood-prone areas. This paper focuses on the innovation management behind RiscBal's design and integration into regional governance. Through interdisciplinary collaboration, stakeholder co-creation, and institutional alignment, RiscBal demonstrates how managing innovation can translate scientific knowledge into actionable, context-sensitive solutions. The system's performance was tested during the August 15, 2024, flash flood in Es Mercadal, Menorca, providing critical lead time for emergency response. However, issues like telecommunication gaps and early-stage hydrological modeling prompted improvements, including redundant systems. Riscbal's modular and interoperable design supports polycentric risk governance and continuous feedback between academia, government, and municipalities. Adaptable to other Mediterranean and global flood-prone regions, it offers a replicable framework for climate resilience. The paper also explores adoption challenges, emphasizing trust, usability and resource constraints.