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This paper aims to emphasize the importance of simulating river hydrodynamics for all the stages of river mouth deviations, since their potential influence on the flood hazard assessment. The case study of the Pescara River mouth deviation in the Abruzzo Region, Italy, has been considered. Only the realized steps of the project have been analyzed, for which the sea level at the mouth has turned out to not remarkably change for the considered layouts. Consequently, flooded areas and flow velocity do not significantly vary between the analyzed configurations. The adopted modeling chain has proved to be a suitable tool to support engineers, contractors, and controlling authorities in the different project phases. [ABSTRACT FROM AUTHOR]

The occurrence of flood events amid the COVID-19 pandemic represents a prominent part of the emerging multi-hazard landscape, as floods are one of the most frequent and destructive natural hazards. This spatial and temporal overlap of hydrological and epidemiological hazards translates into compounded negative effects, causing a shift in the hazard management paradigm, in which hazard interaction takes centre stage. This paper calls into question whether the river flood events that occurred during the COVID-19 pandemic in Romania and the way that they were managed had an impact on the infection with the SARS-CoV-2 virus at county scale. To this end, hazard management data concerning the flood events that were severe enough to impose the evacuation of the population were corroborated with COVID-19 confirmed cases data. A definite link between the flood events and the dynamics of COVID-19 cases registered in the selected counties is difficult to identify, but the analysis shows that all flood events were followed by various size increases in the COVID-19 confirmed cases at the end of the incubation time range. The findings are critically interpreted by providing viral load and social-related contexts, allowing a proper understanding of the interactions between concurrent hazards. [ABSTRACT FROM AUTHOR]

Hospitals play a critical role during disasters where they provide critical medical care to disaster victims and help the community to respond more effectively and recover quicker. However, hospitals face risks from the natural environment, such as flood risks. Amid the increasing flood risks due to climate change, it is essential to examine hospitals' risk exposure. Motivated by this, this paper aims to answer four specific questions related to hospitals in Florida: (1) Are hospitals located in flood zones? (2) What is the relationship between hospital network size and flood hazard? (3) To what extent does hospital flood hazard vary by hospital attributes? (4) How do hospitals' flood hazards differ from other public structures' flood hazards? By leveraging two micro-level datasets, we found that approximately 12% of Florida hospitals are in flood zones, and that hospitals' flood hazard is not influenced by hospital network size or hospital attributes. We also found that hospitals are one of the most flood-prone public structures in our sample, raising questions about public infrastructure in flood management. We conclude by offering recommendations for improving hospital resilience to future flood disasters. [ABSTRACT FROM AUTHOR]

In January 2011, Brisbane, Australia, experienced its first significant flooding in almost four decades. This paper presents the results of a questionnaire conducted in four affected inner western suburbs 7 months after the flood. These locations were specifically chosen as the residents within these communities come from a range of demographic, social, and economic backgrounds. The research utilised a mixed methods approach involving a quantitative questionnaire and qualitative interviews. This paper examines residents' experience of the flood, their thoughts on risk reduction and insurance, what factors helped or hindered response and adaptation to flood risk, and how to articulate shared responsibility for reducing flood risk. Assessing gender, age, income, and previous flood experience, it finds that those with previous flood experience were more likely to have flood insurance but less likely to have taken precautions to prepare for the flood. While almost three-quarters of respondents said they were aware of the flood risk when they moved to the area, they were nonetheless surprised by and largely unprepared for the 2011 flood. The implications of these findings for future flood risk reduction are discussed. [ABSTRACT FROM AUTHOR]

This paper presents an integrated approach to simulate flooding and inundation for small- and medium-sized coastal river basins where measured data are not available or scarce. By coupling the rainfall–runoff model, the one-dimensional and two-dimensional models, and the integration of these with global tide model, satellite precipitation products, and synthetic aperture radar imageries, a comprehensive flood modeling system for Tra Bong river basin selected as a case study was set up and operated. Particularly, in this study, the lumped conceptual model was transformed into the semi-distributed model to increase the parameter sets of donor basins for applying the physical similarity approach. The temporal downscaling technique was applied to disaggregate daily rainfall data using satellite-based precipitation products. To select an appropriate satellite-derived rainfall product, two high temporal-spatial resolution products (0.1 × 0.1 degrees and 1 h) including GSMaP_GNRT6 and CMORPH_CRT were examined at 1-day and 1-h resolutions by comparing with ground-measured rainfall. The CMORPH_CRT product showed better performance in terms of statistical errors such as Correlation Coefficient, Probability of Detection, False Alarm Ratio, and Critical Success Index. Land cover/land use, flood extent, and flood depths derived from Sentinel-1A imageries and a digital elevation model were employed to determine the surface roughness and validate the flood modeling. The results obtained from the modeling system were found to be in good agreement with collected data in terms of NSE (0.3–0.8), RMSE (0.19–0.94), RPE (− 213 to 0.7%), F1 (0.55), and F2 (0.37). Subsequently, various scenarios of flood frequency with 10-, 20-, 50-, and 100-year return periods under the probability analysis of extreme values were developed to create the flood hazard maps for the study area. The flood hazards were then investigated based on the flood intensity classification of depth, duration, and velocity. These hazard maps are significantly important for flood hazard assessments or flood risk assessments. This study demonstrated that applying advanced hydrodynamic models on computing flood inundation and flood hazard analysis in data-scarce and ungauged coastal river basins is completely feasible. This study provides an approach that can be used also for other ungauged river basins to better understand flooding and inundation through flood hazard mapping. [ABSTRACT FROM AUTHOR]

In recently years, flood disasters have produced immense economical and ecological damages in worldwide, particularly in the developing cities. The increasing damages contribute to 'vulnerability' that illustrates which areas are vulnerable to what and why. Therefore, researching vulnerability is an essential and invaluable tool for helping the policy makers to identify the vulnerable people and hot-spots in advance, and to design and implement effective preparedness strategies. In this paper, using the example of Beijing, we propose a quantitative model for measuring flood vulnerability based on land-use patterns which is one of the key variables affected flood vulnerability. By combining the flood hazard characteristic 'inundation depth', a series of flood vulnerability maps demonstrate differential flood vulnerability of flood-prone areas at regional level with the approach of remote sensing and GIS techniques. These maps detect and show the distribution characteristics of vulnerable hot-spots and reveal challenges that the public faced when living in the flood-prone areas. [ABSTRACT FROM AUTHOR]

Strengthening of non-structural measures for flood protection by enforcing natural retention processes on river floodplains not only is required by the EU Floods Directive but also implicates a variety of socio-economic conflicts related to the multipurpose use of floodplains. In order to ensure the achievement of multiple benefits of such non-structural measures in the most effective way, it is crucial to determine which floodplains are highly relevant for preservation and/or restoration not only concerning flood protection (hydrology/hydraulics) but also for ecological and sociological reasons. Therefore, the main objectives of this paper are to identify on different spatial scales those hydrological/hydraulic, ecological and sociological parameters that are important for an integrated evaluation of floodplain effectiveness. The results are finally assembled in the novel multidisciplinary floodplain evaluation matrix (FEM) serving as decision support for the relevant stakeholders and indicating where efforts of floodplain preservation/restoration should be spent first within an integrated flood risk management. At the end of this paper, an integrative evaluation on macro-scale level for the Austrian Kamp River is exemplarily presented. Detailed sectoral investigations of the hydrological and hydraulic parameters are further described in a case study of the Austrian Danube (see paper 'Assessing the role of floodplains along the Austrian Danube for flood hazard reduction using the hydrological and hydraulic parameters of the FEM-method'). [ABSTRACT FROM AUTHOR]

Recent attempts to integrate geographic information systems (GIS) and participatory techniques have given rise to terminologies such as participatory GIS and community- integrated GIS. Little has been published about the usefulness of participatory GIS, especially for purposes of flood risk assessment in Zimbabwe. This paper attempts to address this research gap and demonstrates that when combined with participatory methodologies, GIS can provide a mechanism for assessing flood extend in flood-prone communities of Chadereka in Muzarabani communal lands. Flood risk is increasing in the flood-prone areas in Zimbabwe, especially in remote areas where gauging stations are non-existent because of lack of hydrometeorological and climate data for these areas, historical and projected flood events cannot be assessed through modelling. The spatial extent of the flood zone of the December 2007 flash flood event that took place in Chadereka area was mapped using participatory geographic information systems (PGIS), as well as the data collected through interviews that were held with key informants and focus group discussions. Using this approach, a flood extend assessment map was drawn by triangulating the resultant 12 PGIS maps produced by the local community. The results of the study suggest that if conventional GIS and flood modelling is cross checked with PGIS and fieldwork results, the spatial characteristics of floods in ungauged flood-prone areas can be improved and enable the profiling of floods in Chadereka ward. [ABSTRACT FROM AUTHOR]

International Disaster Risk Reduction Frameworks and Indian Plans advocate shared responsibility for reducing disaster risk, in which community vulnerability and resilience conditions are central. This paper presents a case study from the Indian Himalaya (Kullu District) of community vulnerability and resilience conditions following damaging floods, primarily the 1994 Phojal Nalla flood, through the concepts of community heritage and capital. Data were collected in the period 2013-2016, using semi-structured interviews (n = 129), village reconnaissance and archival/contemporary data searches. The connections between heritage, capital, vulnerability and resilience are complex, but results demonstrate ‘knowledge’ is the principal driver of resilience conditions, via facets of heritage (e.g. religious infrastructure and activities, traditional architectural vernacular, and multi-generational attachments to place) and capital (e.g. income diversification, access to communication technologies, societal welfare measures and positive interactions with water). Persisting vulnerabilities stem from differential access to and implementation of best practice knowledge, governed by social, economic and political conditions. Further improvements in risk reduction require greater consideration of the following: (1) the integration of community local knowledge into the overall disaster management process; (2) the opportunities offered by mobile phone and other technologies for generating and sharing knowledge across society; and (3) the value of under-utilised knowledge of past disaster events, assembled from a systematic evaluation of oral, documentary and landscape evidence, to risk reduction. [ABSTRACT FROM AUTHOR]

Flood hazard maps are one of the main components of any flood risk management strategy. It is predicted that the degree of flood risk is going to significantly increase in the future due to climatic and environmental changes, and hence it is increasingly important that state-of-the-art methods are implemented for assessing human stability in floodwaters. Therefore, this paper focuses on proposing more accurate and detailed guidelines for predicting flood hazard indices in small and steep river basins or catchments, prone to the occurrence of flash flooding. The results obtained in this study indicate that for river basins with an average bed gradient greater than 1% (i.e. torrential or flashy river basins or catchments), then the flood hazard indices should be predicted using criteria which are based on the physical interpretation of the processes that affect the human stability in floodwaters, i.e. mechanics based and experimentally calibrated flood hazard assessment methods. [ABSTRACT FROM AUTHOR]

More recently, driven by rapid and unguided urbanisation and climate change, Ghanaian cities are increasingly becoming hotspots for severe flood-related events. This paper reviews urbanisation dynamics in Ghanaian cities, and maps flood hazard zones and access to flood relief services in Kumasi, drawing insight from multi-criteria analysis and spatial network analysis using ArcGIS 10.2. Findings indicate that flood hazard zones in Kumasi have been created by natural (e.g., climate change) and anthropogenic (e.g., urbanisation) factors, and the interaction thereof. While one would have expected the natural factors to guide, direct and steer the patterns of urban development from flood hazard zones, the GIS analysis shows that anthropogenic factors, particularly urbanisation, are increasingly concentrating population and physical structures in areas liable to flooding in the urban environment. This situation is compounded by rapid land cover/use changes and widespread haphazard development across the city. Regrettably, findings show that urban residents living in flood hazard zones in Kumasi are also geographically disadvantaged in terms of access to emergency services compared to those living in well-planned neighbourhoods. [ABSTRACT FROM AUTHOR]

Sewer inlet structures are vital components of urban drainage systems and their operational conditions can largely affect the overall performance of the system. However, their hydraulic behaviour and the way in which it is affected by clogging is often overlooked in urban drainage models, thus leading to misrepresentation of system performance and, in particular, of flooding occurrence. In the present paper, a novel methodology is proposed to stochastically model stormwater urban drainage systems, taking the impact of sewer inlet operational conditions (e.g. clogging due to debris accumulation) on urban pluvial flooding into account. The proposed methodology comprises three main steps: (i) identification of sewer inlets most prone to clogging based upon a spatial analysis of their proximity to trees and evaluation of sewer inlet locations; (ii) Monte Carlo simulation of the capacity of inlets prone to clogging and subsequent simulation of flooding for each sewer inlet capacity scenario, and (iii) delineation of stochastic flood hazard maps. The proposed methodology was demonstrated using as case study design storms as well as two real storm events observed in the city of Coimbra (Portugal), which reportedly led to flooding in different areas of the catchment. The results show that sewer inlet capacity can indeed have a large impact on the occurrence of urban pluvial flooding and that it is essential to account for variations in sewer inlet capacity in urban drainage models. Overall, the stochastic methodology proposed in this study constitutes a useful tool for dealing with uncertainties in sewer inlet operational conditions and, as compared to more traditional deterministic approaches, it allows a more comprehensive assessment of urban pluvial flood hazard, which in turn enables better-informed flood risk assessment and management decisions. [ABSTRACT FROM AUTHOR]

The present paper reviews selected outcomes of the FLORIST project devoted to flood risk in the region of the northern foothills of the Tatra Mountains in Poland and summarizes novel results. The project encompassed theoretical, field, and modeling work. It was focused around observation-based hydroclimatology; projections for the future; dendrogeomorphology; as well as influence of transport of large wood on fluvial processes. The project improved understanding and interpreting changes in high-flow frequency and magnitude as well as changes in flood risk in the region, related to the presence of large wood in mountain streams. A unique database on past episodes of intense precipitation and flooding was created, harnessing multiple sources. The project showed that the analysis of tree rings and wood logs can offer useful information, complementing and considerably enriching the knowledge of river floods in the region of northern foothills of the Tatra Mountains. Retrospective and scenario-defined modeling of selected past fluvial events in the region was also performed. [ABSTRACT FROM AUTHOR]

Background: Operational large-scale flood monitoring using publicly available satellite data is possible with the advent of Sentinel-1 microwave data, which enables near-real-time (at 6-day intervals) flood mapping day and night, even in cloudy monsoon seasons. Automated flood inundation area identification in near-real-time involves advanced geospatial data processing platforms, such as Google Earth Engine and robust methodology (Otsu's algorithm). Objectives: The current study employs Sentinel-1 microwave data for flood extent mapping using machine learning (ML) algorithms in Assam State, India. We generated a flood hazard and soil erosion susceptibility map by combining multi-source data on weather conditions and soil and terrain characteristics. Random Forest (RF), Classification and Regression Tool (CART), and Support Vector Machine (SVM) ML algorithms were applied to generate the flood hazard map. Furthermore, we employed the multicriteria evaluation (MCE) analytical hierarchical process (AHP) for soil erosion susceptibility mapping. Summary: The highest prediction accuracy was observed for the RF model (overall accuracy [OA] > 82%), followed by the SVM (OA > 82%) and CART (OA > 81%). Over 26% of the study area indicated high flood hazard-prone areas, and approximately 60% showed high and severe potential for soil erosion due to flooding. The automated flood mapping platform is an essential resource for emergency responders and decision-makers, as it helps to guide relief activities by identifying suitable regions and appropriate logistic route planning and improving the accuracy and timeliness of emergency response efforts. Periodic flood inundation maps will help in long-term planning and policymaking, flood management, soil and biodiversity conservation, land degradation, planning sustainable agriculture interventions, crop insurance, and climate resilience studies. [ABSTRACT FROM AUTHOR]

One of the natural threats that arises as a result of temporary surface runoff is flooding, which has a large amount of solid material, a high level of water in the streams, a sudden appearance, and a rapid flow velocity. The Wadi Amlog Basin is characterized by the lack of rain and the prevalence of drought, but it is exposed to sudden rains that lead to surface runoff in its dry valleys in a way that results in threats to infrastructure and spatial development in the coastal region. Within this framework, the purpose of this research is to investigate the possible areas of flood hazard by using GIS techniques based on morphometric assessment parameters to determine the risk level of specified subbasins from a digital elevation model (DEM) using remotely sensed SRTM images. The case study results utilized five evaluation degrees, very low, low, moderate, high, and very high, to interpret the flood danger, in a way that contributes to protecting the places most affected by the dangers of floods in the subbasins in the study area. [ABSTRACT FROM AUTHOR]

The accurate forecast from Hurricane Sandy sea surge was the result of integrating the most sophisticated environmental monitoring technology available. This stands in contrast to the limited information and technology that exists at the community level to translate these forecasts into flood hazard levels on the ground at scales that are meaningful to property owners. Appropriately scaled maps with high levels of certainty can be effectively used to convey exposure to flood hazard at the community level. This paper explores the most basic analysis and data required to generate a relatively accurate flood hazard map to convey inundation risk due to sea surge. A Boolean overlay analysis of four input layers: elevation and slope derived from LiDAR data and distances from streams and catch basins derived from aerial photography and field reconnaissance were used to create a spatial model that explained 55 % of the extent and depth of the flood during Hurricane Sandy. When a ponding layer was added to the previous model to account for depressions that would fill and spill over to nearby areas, the new model explained almost 70 % of the extent and depth of the flood. The study concludes that fairly accurate maps can be created with readily available information and that it is possible to infer a great deal about risk of inundation at the property level, from flood hazard maps. The study goes on to conclude that local communities are encouraged to prepare for disasters, but in reality because of the existing Federal emergency management framework there is very little incentive to do so. [ABSTRACT FROM AUTHOR]

Due to their retention capacity, extensive flat floodplains have a significant impact on the propagation and transformation of flood waves. The conveyance and retention capacity of an area is significantly influenced by land use. The paper presents results of a hydraulic analysis of the impact of land use on the run-off regime in a retention area and consequently on flood wave propagation. The land use of the retention area was simulated by hydraulic roughness. The simulations were performed for flood waves with different values of peak discharge and with two lengths of duration. A spectrum of flood waves in which the retention areas have significant impact on the propagation was considered. To isolate the impact of topographical characteristics of riparian and retention areas on the communication of water between the channel and retention area, as well as on the formation of parallel streams in the area, a theoretical modelling area with simplified geometry was used in the first phase. Conclusions based on the results of the first-phase simulations were tested on a practical case of the plain Krško-Brežiško polje, where data from field measurements as well as data from the physical model were used in the numerical calibration of the model. [ABSTRACT FROM AUTHOR]

The identification of flood-prone areas is a critical issue becoming everyday more pressing for our society. A preliminary delineation can be carried out by DEM-based procedures that rely on basin geomorphologic features. In the present paper, we investigated the dominant topographic controls for the flood exposure using techniques of pattern classification through linear binary classifiers based on DEM-derived morphologic features. Our findings may help the definition of new strategies for the delineation of flood-prone areas with DEM-based procedures. With this aim, local features-which are generally used to describe the hydrological characteristics of a basin-and composite morphological indices are taken into account in order to identify the most significant one. Analyses are carried out on two different datasets: one based on flood simulations obtained with a 1D hydraulic model, and the second one obtained with a 2D hydraulic model. The analyses highlight the potential of each morphological descriptor for the identification of the extent of flood-prone areas and, in particular, the ability of one geomorphologic index to represent flood-inundated areas at different scales of application. [ABSTRACT FROM AUTHOR]

China's urban environments are particularly vulnerable to flooding due to climate change and rapid urbanization. Study of the urban flood risk analysis has significantly increased over the past decade, and this paper therefore reviews the main results (i.e. theoretical basis, methods, techniques, case studies) obtained in the literature from China. We focus on the following topics: (1) urban flood hazard analysis, (2) exposure and vulnerability analysis, and (3) urban flood risk assessment. Recent advances made in the research area are presented with suggestions for further research to improve the availability and reliability of urban flood risk analysis. [ABSTRACT FROM AUTHOR]

Growing concern on climate-related flood hazards has led to increasing interest in understanding the interactions between climate, flood, and human responses. This paper jointly investigates climate change trends, impacts on flood events, flood vulnerability and risk, and response strategies in the Pearl River Delta (PRD), a rapidly urbanizing coastal area in southeast China. Our analysis based on a reanalysis dataset and model projections are integrated with literature results, which indicates a climate scenario of increasing mean temperature, precipitation, sea level, typhoon intensity, and the frequency of extreme weather events in the PRD. These trends, together with the continuing urbanization in flood-prone areas, are expected to increase flood frequency and aggravate both the scale and degree of flooding in the PRD area. We further estimate the flood vulnerability of the 11 PRD cities using the indicator system method. The results suggest that the exposure and sensitivity of central cities (Hong Kong, Macao, Shenzhen, and Guangzhou) are very high because of highly exposed populations and assets located in lowland areas. However, the potential vulnerability and risk can be low due to high adaptive capacities (both by hard and soft flood-control measures). A novel framework on flood responses is proposed to identify vulnerable links and response strategies in different phases of a flood event. It further suggests that the flood risks can be mitigated by developing an integrated climate response strategy, releasing accurate early warning and action guidance, sharing flood-related information, and applying the advantages of online social network analysis. [ABSTRACT FROM AUTHOR]

Among natural hazards and disastrous outcomes, floods have tremendous impacts on infrastructure as well as on humans. In the present study, we determined flood hazard using several hydro-geomorphic factors in the Darab watershed. For this purpose, the Analytical Hierarchical Process (AHP) and fuzzy logic were used in the initial phase of the mapping process to overlap layers. The kernel density and zonal statistics were employed to calculate flood hazard density and flood hazard zones, respectively. In addition, the spatial statistics were considered to identify floods with high and low clusters in flood hazardous zones using ArcGIS Pro. The results showed that the Gamma operator (0.9) with the AUC value of 0.8924 was the optimal operator for flood zonal statistics. Only 26.45% of the study area had high flood intensity, and only two high-hazard flooding clusters were detected in the Darab watershed. The heighest value of flood was recognized in the north and northeast of the study area, which corresponded to small towns with less than 5000 inhabitants. Our experiments demonstrated that the integration of geospatial analysis with spatial statistics may provide a reliable method to assess flood hazard. [ABSTRACT FROM AUTHOR]

Copyright of Review of Regional Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the current study, the one-dimensional/two-dimensional (1D/2D) coupled hydrodynamic model is used for the development of flood hazard maps for the frequently flooded coastal urban floodplain of the Surat city, India. The releases from the Ukai dam and tidal levels at the Arabian Sea are considered as upstream and downstream boundary conditions, respectively. The floodplain roughness was estimated using the existing land use land cover (LULC) classification, and the performance of the developed coupled hydrodynamic model was evaluated against the past flood data of year 2006 and 2013. The flood frequency analysis was carried out for peak inflow into the Ukai reservoir, and subsequently, the design flood hydrographs for different return periods have been developed. Finally, the simulated model output has been used to develop multi-parameter flood hazard maps defining the stability of people, vehicles, and buildings. More than 80% of the entire coastal urban floodplain of the Surat city is submerged during 100-year return period flood, with West and North zone of the city being the worst affected regions. Out of the total flooded area, nearly 20% area is under significant hazard for adults. The 27% area offers instability hazard to large four-wheel drive vehicles, whereas 14% area is affected with moderate to high hazard for buildings. The instability index for specific vehicle types is dominated by floating of small and large cars over 90% of the flooded area. Further, the combined hazard maps revealed that 14% of the flooded area is under very severe hazard category, posing a threat to the stability of people, vehicles, and buildings. The developed hazard maps will work as an effective non-structural measure for local administrative agencies to minimize the losses and better future planning. [ABSTRACT FROM AUTHOR]

Floods are among the most destructive disasters because they cause immense damage to human life, property (land and buildings), and resources. They also slow down a country's economy. Due to the dynamic and complex nature of floods, it is difficult to predict the areas that are prone to flooding. In this study, an attempt was made to create a suitability map for future urban development based on flood vulnerability maps for the catchment area of Taif, Saudi Arabia. Three models were used for this purpose, including bivariate (FR), multivariate (LR), and machine learning (SVM) were used. Thirteen parameters were used as flood-contributing parameters. The inventory map was constructed using field surveys, historical data, analysis of RADAR (Sentinel-1A), and Google Earth imagery collected between 2013 and 2020. In general, 70% flood locations were randomly selected from the flood inventory map to generate the flood susceptibility model, and the remaining 30% of the flood locations were used for model validation. The flood susceptibility map was classified into five zones: very low, low, moderate, high, and very high. The AUC value used to predict the performance of the models showed that the accuracy reached 89.5, 92.0, and 96.2% for the models FR, LR, and SVM, respectively. Accordingly, the flood susceptibility map produced by the SVM model is accurate and was used to produce a flood vulnerability map with the help of urban and road density maps. Then slope and elevation maps were integrated with the flood vulnerability model to produce the final suitability map, which was classified into three zones: isolated zone, low suitability, and high suitability areas. The results showed that the highly suitable areas are located in the east and northeast of the Taif Basin, where the flood risk is low and very low. The results of this work will improve the land use planning of engineers and authorities and take possible measures to reduce the flood hazards in the area. [ABSTRACT FROM AUTHOR]

The Tista floodplain is one of the major food baskets of North Bengal and is sensitive to a multitude of issues regarding vulnerability. The riparian areas and the river island or charland of the lower Tista River basin in India, specifically from Sevoke to the Indo-Bangladesh border, generally suffer due to flood-prone, river course shifting, limited livelihood activities, low adaptive capacity, and poor accessibility. The present work is conducted to assess the livelihood vulnerability based on the livelihood vulnerability index (LVI) framework of the agriculture-dependent riparian villages and the charlands of the River Tista in the Jalpaiguri district. Total 337 households of five villages from the Mal and Maynaguri block at the left bank of the Tista River were selected to conduct the field survey. The livelihood vulnerability was assessed based on eight major components (viz., socio-demographic profile, health condition, livelihood strategies, food support, water support, climatic variability, flood hazards, and social safety) and 42 sub-components. The three contributing factors, i.e., adaptive capacity, sensitivity, and exposure, have been combined to calculate the livelihood vulnerability employing the LVI and LVI-IPCC methodologies. The outcome of the study exhibit that LVI scored highest in Premganj Majhiali (0.436), followed by Basusuba (0.403), Uttar Marichbari (0.349), Domohani (0.335), and Chat Rarpur village (0.328). According to the LVI-IPCC results, Basusuba has the most vulnerability (0.015), whereas Domohani has the least (0.007). In terms of flood hazard, variations were noticed based on increasing distance from the river. Lack of adaptive capacity prevailed in the villages with significant flooding events. Building awareness of the inhabitants will be an effective way to improve the adaptive capacity of the rural villagers. Therefore, giving priority to the policies depending on the natural environment of the active flood-prone region would make long-term sustainability. [ABSTRACT FROM AUTHOR]

Wadi El-Matulla, located in the eastern desert of Egypt, is the most important water basin. The Qift–Qusayr highway (west–east direction) and the Cairo–Aswan eastern desert highway (north–south direction) pass through the watershed. Many urban areas (villages and industrial areas) and agricultural lands are located at the outlet of these basins. In addition, the basin has promising potential for future economic and urban development as it is located within the Golden Triangle (governmental megaproject). The current study investigates flood hazard modeling and its impact on the area. To determine the optimal flood susceptibility mapping algorithm, performance comparisons of three techniques were conducted: logistic regression (LR), extreme gradient boosting (EGB), and random forest (RF). Remote sensing, topographic, geologic, and meteorological data were used with the help of field visits to provide the spatial and inventory database required by the models. The performance and reliability of the predictions of the proposed models were evaluated using five statistical indices: receiver operating characteristic–area under the curve, overall accuracy (OAC), kappa index, root mean square error (RMSE), and mean absolute error (MAE). The performance of the models showed that the values of ROC (93, 86 and 80%), OAC (88, 82 and 76%), kappa index (0.85, 0.75 and 0.51), RMSE (0.34, 0.42 and 0.49) and MAE (0.12, 0.18 and 0.24) for RF, EGB, and LR, respectively. Based on AUC values, RF and EGB models provide excellent and very good prediction for flood susceptibility. Our results show that RF is the optimal algorithm for flood susceptibility mapping, followed by EGB and LR. Consequently, the predictive power of RF model is quite good and the flood susceptibility map was classified into five classes, namely very low (51.7%), low (23.7%), moderate (16.2%), high (7.1%), and very high (1.3%). Ultimately, the RF model was verified using sentinel-1 imagery for real floods in 2016 and 2021, and it provides good agreement. The optimal model could be useful for decision makers and planners to protect existing facilities and plan future projects in non-flood-prone areas. Accordingly, the most suitable areas for future development need to be distributed mainly in the low and very low flood hazard areas. [ABSTRACT FROM AUTHOR]

Nowadays, preparing natural hazard maps has become essential to protect society and its infrastructure from future natural disasters. In this context, the multi-criteria semi-quantitative technique, the analytical hierarchy process (AHP) was integrated into the Geographic Information System (GIS) environment to produce a flood hazard map. The Lower Mahananda basin of India was chosen as the study area that annually suffers from damage from floods. The produced map was categorized into five classes as the zones of flood susceptibility, namely very high, high, moderate, low and very low. The corresponded zones were then examined using sensitivity analysis, and the results show there are very small differences in the spatial distribution of flood susceptible zones. The high flood hazard zones (18%) are located generally along river tracts in the lower portion of the study area that gets flooded more or less every year. The comparison found between the various flood susceptible zones, and the rise in the water level at the Mahananda conveys the accuracy and reliability of the applied methodology. Moreover, the settlement zones were identified within the high flood probable category and the sub-districts situated along the western margin have been found with inadequate medical facilities to combat the flood events. Therefore, the proposed methodology and resultant analysis of the work can be useful for local government authorities to prepare flood mitigation plans and strategies. [ABSTRACT FROM AUTHOR]

The assessment of flood impact on a Water Supply System (WSS) requires a comprehensive approach including several scales of analysis and models and should be managed in the Water Safety Plans (WSP), as recommended in the EU Water Directive 2020/2184. Flooding can affect the quality of groundwater and surface water resources and can cause supply service interruption due to damaged infrastructures. A complete approach to address flood impact on WSS is required but not yet available, while only specific aspects were investigated in details. This work introduces a comprehensive tool named WAter Safety Planning Procedures Decision Support System (WASPP–DSS) developed in the context of MUHA (Multihazard framework for Water Related risks management) project. The tool is mainly addressed to small water utilities (WU) for supporting WSP development and is based on two main premises: 1) a correct approach for WSS risk analysis requires a multi-hazard perspective encompassing all the system components and different hazards; 2) other institutions in addition to WUs have to be involved in WSS risk analyses to harmonize monitoring and response procedures. The tool is here applied on risks associated to flooding and demonstrated for three case studies. The WASPP–DSS, tested by eight WUs, was found a potentially valid support for small WUs that must start drafting the WSP in a comprehensive way and can provide a common shared scheme. Improvements are desirable, as including a specific section to consider the issue of loss of water resources from reservoirs due to overflow. [ABSTRACT FROM AUTHOR]

Flooding is one of the major natural catastrophic disasters that causes massive environmental and socioeconomic destruction. The magnitude of losses due to floods has prompted researchers to focus more on robust and comprehensive modeling approaches for alleviating flood damages. Recently developed multi-criteria decision making (MCDM) methods are being widely used to construct decision-making process more participatory, rational, and efficient. In this study, two statistical MCDM approaches, namely the analytical hierarchy process (AHP) and the technique for order preference by similarity to ideal solution (TOPSIS), have been employed to generate flood risk maps together with hazard and vulnerability maps in a GIS framework for Navsari city in Gujarat, India, to identify the vulnerable areas that are more susceptible to inundation during floods. The study area was divided into 10 sub areas (i.e., NC1 to NC10) to appraise the degree of flood hazard, vulnerability and risk intensities in terms of areal coverage and categorized under 5 intensity classes, viz., very low, low, moderate, high, and very high. A total of 14 flood indicators, seven each for hazard (i.e., elevation, slope, drainage density, distance to river, rainfall, soil, and flow accumulation) and vulnerability (i.e., population density, female population, land use, road network density, household, distance to hospital, and literacy rate) were considered for evaluating the flood risk. Flood risk coverage evaluated from the two approaches were compared with the flood extent computed from the actual flood data collected at 36 random locations. Results revealed that the TOPSIS approach estimated more precise flood risk coverage than the AHP approach, yielding high R2 values, i.e., 0.78 to 0.95 and low RMSE values, i.e., 0.95 to 0.43, for all the 5 risk intensity classes. The sub areas identified under "very high" and "high" risk intensity classes (i.e., NC1, NC4, NC6, NC7, NC8, and NC10) call for immediate flood control measures with a view to palliate the extent of flood risk and consequential damages. The study demonstrates the potential of AHP and TOPSIS integrated with GIS towards precise identification of flood-prone areas for devising effective flood management strategies. [ABSTRACT FROM AUTHOR]

The increasing rate of anthropic activities in flood-prone areas and the effects of climate change are aggravating the dangers posed by floods to people. One of the main reasons for fatality during flood events is walking through floodwaters. Although authorities strongly advise against walking in flood waters, evacuations or the accessing of flooded areas by emergency services might be necessary. This research proposes a novel approach to increasing resilience by retrofitting existing infrastructures to enhance evacuation and access routes by reducing flood hazard rate based on flood and pedestrian characteristics. The methodology was applied to flash floods in two case studies in the UK, namely Boscastle and Borth, highlighting that retrofitting small regions of the existing roads and pathways to reduce flood hazard can enhance people's safety during the evacuation, and hence provides a solution to improve the resilience of the existing environment. [ABSTRACT FROM AUTHOR]

The current magnitude of flooding in Ethiopia is unprecedented. It is a typical disaster in Ethiopia with the evidence of the recent Dire Dawa and Omo River surroundings, especially during the rainy season. The situation resulted in much human death and destruction of infrastructures in different parts of the country, and the Alawuha watershed is among the typical areas for this problem. The study's aim was to evaluate the flood risk management practices and map flood-vulnerable areas in the Alawuha catchment. Geographic information system (GIS) multi-criteria analysis and remote sensing with field verification were employed to meet the objective of this study. Slope, elevation, rainfall, drainage density, soil type, and distance to rivers are flood event aggravating factors in this study. These factors were weighted accordingly with their contribution to flood hazards. In addition, land use/land cover (LULC) and population distribution were identified as flood vulnerability factors. The weighted overlay analysis result shows that Sanka, Afrikari, Gedo-ber, Hara, and the surroundings, Woldia, were identified as high flood risk areas of the watershed. To minimize this problem, applying physical and biological measures at the watershed level is recommended. [ABSTRACT FROM AUTHOR]

The present work investigated the deteriorating condition of Tawi River, Jammu, India, using geoinformatics techniques. The parameters analysed in this study include flood hazard zonation assessment, water quality mapping and monitoring, soil erosion assessment, spatial analysis of site suitability for solid waste dumping, evaluation of sewer and sanitation data and computation of relationship between river discharge and climatic variables. Analytical hierarchy process was used to assign ranks and weights to different layers to prepare flood hazard assessment and site suitability for solid waste dumping maps. The results suggest that the area of Tawi catchment prone to high floods is 563 km2, severe soil erosion is 860 km2, and 547 km2 of the area was suitable for solid waste dumping. The four water quality parameters, i.e. turbidity, calcium content, total hardness and total dissolved solids, collected from seven stations, revealed water quality degradation downstream. The sewer and sanitation data procured from six stations further revealed that only a small fraction of the population could dispose of the sewer and sanitation wastes properly. The sullage wastes allowed freely to flow in the Tawi River severely impacts the river's water quality. River discharge showed a positive correlation of 0.56 with maximum temperature, 0.72 with minimum temperature and 0.86 with rainfall. Overall, the study indicates that the river under investigation faces a serious threat of pollution, erosion vulnerability and solid waste dumping. [ABSTRACT FROM AUTHOR]

The influences of climate change on the features of extreme rainfall events have become unprecedented that needs improved understanding at all levels for planning effective management strategies of the potential risks. This study aims to assess the potential influences of climate change on extreme rainfall characteristics in flood-vulnerable city of Adama. Daily precipitation records of 1967–2016 and projection of global circulation models (GCMs): CanESM2 and HadCM3 for 2021–2070 were disaggregated into shorter time resolutions using the Hyetos model. Gumbel type I probability distribution and power-regression model ( i = a D b) were used for deducing intensity–duration–frequency (IDF) curves and for describing their functions, respectively. The extreme rainfall intensity of the historical and future periods for a range of storm durations and return periods were compared and contrasted. A close agreement is obtained between the observed and the modeled rainfall intensity with high values of coefficient of determination (> 0.996) and Nash–Sutcliffe efficiency (> 0.850). Besides, statistically significant (p < 0.05) direct linear relationship is found between the return periods and the coefficient parameter of the IDF models. Moreover, the intensity of extreme precipitation over 2021–2070 in Adama city would increase up to 49.5%, depending on storm duration and return period considered. This could have consequences of the way the city's drainage infrastructures are designed, operated, and sustained. Hence, flood-prone areas should be recognized in order to formulate effective strategies for mitigation and adaption of potential impacts. The standards for designing future drainage infrastructures should also be updated aiming to reflect the effects of climatic change. [ABSTRACT FROM AUTHOR]

Floods have the potential to cause severe damages to humankind around the world. Similarly, the annual monsoon flooding phenomena have had devastating consequences on the Upper Ping River basin throughout the years. The current administrative structure for implementing flood mitigation and adaptation measures lacks effective utilization of locally available resources to provide comprehensive protection against flood-triggered devastation. That is why this study addressed this gap by conducting a flood hazard assessment at the sub-district level. The study assesses flood offsetting potential of local adaptation measures. A modeling approach was used that consists of developing the MIKE 11 and MIKE 21 hydrodynamic models for 1-D and 2-D channel conditions, respectively. MIKE 11 and MIKE 21 models were calibrated against observed discharge and water level (1D) flood extent (2D), respectively. Flood inundation and hazard maps were reproduced and categorized into several classes based on defined critical depths for 2, 5, 10, 25, 50, and 100 years return periods. The flood inundations reproduced on 601.8–996.9 km2 (2.37–3.94% of total basin area) for 5–100-year return period floods, respectively. Based on flood hazard results, the "high hazard" category took first place with the largest flooded area, followed by "very high hazard" and "low hazard" categories, and the "medium hazard" category was ranked at last place with the least coverage of inundated area. To improve future flood protection, the existing administrative structure for flood adaptation and mitigation has to be updated based on an integrated flood management strategy. [ABSTRACT FROM AUTHOR]

Annual fluvial and pluvial floods happened in Lower Ping River Basin, Thailand. A flood hazard assessment approach was performed in the present study to evaluate flood impacts. The coupled 1D-2D hydrodynamic (HD) modeling package was applied for different return periods to investigate and classify the flood hazards. The 1D hydrodynamic model was calibrated for flood year 2011 at discharge and water level stations. The 2D hydrodynamic model was calibrated using observed flood map. Flood hazards were categorized based on critical flood depths for flooding scenarios of 2-, 5-, 10-, 25-, 50-, and 100-year return periods. The results showed that 28.8% of the total basin area (2423.8 km2) was flooded during the 100-year return period, and the maximum flood inundation area was observed in Kamphaengphet and Nakhon Sawan provinces. Mostly, the flooded area under each return period was categorized under high hazard, followed by low and medium, and the least area was classified under a very high hazard level. More than 40% of sub-districts' area of Kamphaengphet and Nakhon Sawan provinces were flooded, which is located along the Ping River, while less than 20% sub-districts' area was flooded in Tak Province. The government and local stakeholders need to consider structural and nonstructural measures to reduce flood impacts in three provinces, and priority-based areal flood management approaches should be considered during the implementation of flood mitigation measures. [ABSTRACT FROM AUTHOR]

Highways in arid regions are highly exposed to damage by floods. This requires intensive analysis of flood quantity, time and direction that can be used to design the suitable protection measures. Flood hazard mitigation can be achieved through calculating quantities and distribution by deriving a rainfall–run-off relationship which plays an important role in watershed managements and protection. This study aims to determine the overflow stream ways crosswise over roads and their stream sizes under various precipitation events of 10, 25, 50 and 100 return periods. This can be used in the planning of the flood alleviation measures to protect the roads from flood hazards. This methodology is applied to a real area, Tama road as a part of King Abdul-Aziz Highway, Kingdom of Saudi Arabia. Recorded data were gathered for the study area, and hydrological models were used for delineation of the study area. The results indicated that the proposed site of the new road is extremely exposed to flash flood hazard and protection measures are essential to protect the road. A system of protection is proposed and designed including 7 channels and 2 culverts to mitigate the flood hazard in the area of study. The proposed mitigation system is fit for protecting this area from flood hazards. Protection of such roads helps to save lives of people and reduce the cost of maintenance and rehabilitation due to damages caused by flood. [ABSTRACT FROM AUTHOR]

Flash flood is disastrous; it losses property and life. Its effect is intensified while it occurs in semiarid region because of less preparedness. The present case conferred about a flash flood in semiarid region in Gujarat which was affected by flood in 2015 and 2017. Massive loss of lives and properties has been observed after the event. Now, recuperating the region against flood losses, it was a prime requirement to distribute the flood relief packages to the flood-susceptible areas. To identify the flood hazards and flood risk and assess the flood vulnerability in Rel River catchment, the region is divided into 52 micro-watersheds using RS and GIS techniques. The morphology of the Rel River catchments has been explored using the morphometric analysis. The priority rank and category for each micro-watershed were assigned based on compound factor values, whereas compound factor was calculated using weighted sum analysis techniques. Flood hazard zone map was prepared, and flood vulnerability has been characterized from very low to very high. Furthermore, the multi-criteria analysis was used to calculate the risk factor for the basin and AHP-MCE method was used to find the normalized weights of each factor (LU/LC, CF, soil, slope, drainage density) that were significant to the flood disaster. The integration of flood hazard map along with these parameters helped to understand the sensitivity of flash floods at different locations within the study area. Flood risk map was further analyzed at village level, and it has been identified that 17 out of 39 villages were at high risk, 12 villages were at moderate risk and 10 villages were at low risk. The study helped to clearly identify villages vulnerable to flood risk where more relief and flood insurance packages need to be allotted. Thus, the present method and integrated approach would be a useful tool for the decision maker to distribute the flood relief package in flash flood-prone area. [ABSTRACT FROM AUTHOR]

Flood emergency management practices cover various aspects of flooding, such as demography, infrastructure, economy, transportation, and agriculture. Emergency managers and local authorities work to understand existing and potential impacts of flooding in their communities. HAZUS is one of the most widely used GIS-based desktop software packages designed to help emergency managers to simulate floods and observe their possible effects in their communities. Using HAZUS, emergency managers can prioritize regions to receive help, allocate resources, and plan mitigation measures in the disaster area. However, the system has limitations in terms of its technical requirements, the number of flood scenarios and data options, accessibility, and performance. In this study, we present an integrated and scalable web framework for HAZUS-MH flood loss estimation analysis. By taking advantage of the Iowa Flood Center's extensive flood inundation map repository for Iowa, we could enable interactive analysis between flood map raster and census data to demonstrate flooding impacts in Iowa communities. High-resolution pre-computed flood inundation maps allowed us to execute damage and loss analyses within seconds. Using visualization techniques on the web, users can access damage and loss analysis without specific software or technical expertise. Moreover, by connecting new data sources, we also enabled many different analyses through the web-based system, including agricultural damage and loss analysis and flooded transportation segments. The generalized architecture of the system allows the framework to analyze any region and community. [ABSTRACT FROM AUTHOR]

This study focused on flood damage assessment for future floods under the impact of climate change. Four river basins of Southeast Asia were selected for the study. They included the Pampanga River Basin (PRB) in the Philippines, the Solo River Basin (SRB) in Indonesia, the Lower Mekong River Basin (LMRB) in Cambodia and Vietnam, and the Chao Phraya River Basin (CPRB) in Thailand. Flood damage to rice crops was assessed by flood damage functions considering flood depth and duration and the growth stage of rice plants. Flood characteristics such as flood depth, duration, and distribution were computed using the rainfall–runoff–inundation model to assess flood hazards under the present and future climatic conditions produced by MRI-AGCM3.2S. The damage assessment methodology for rice crops employed in this study was verified using data on past flood events. Then, flood damage assessment was conducted for both the present climate (1979–2003) and future climate (2075–2099) conditions, using MRI-AGCM3.2S precipitation datasets. Flood damage was assessed for worst cases chosen from each climate period and for floods of 50- and 100-year return periods with different rainfall patterns chosen from each climate scenario. The results of flood hazard and damage assessment show that the flood inundation area for a 100-year flood may increase in the future by 20% in PRB; by 66% in SRB; by 27% in LMRB; and by 27% in CPRB. The flood damage area of paddy fields for a 100-year flood may also increase in the future by 16% in PRB; by 55% in SRB; by 23% in LMRB; and by 13% in CPRB. [ABSTRACT FROM AUTHOR]

In this study, the first ever Sea, Lake, Overland Surges from Hurricanes (SLOSH) grid was built for the Yucatan Peninsula. The SLOSH model was used to simulate storm surges in the coastal area of the states of Yucatan and Campeche (Mexico). Based on climatology, more than 39,900 hypothetical hurricanes covering all possible directions of motion were synthesized. The storm intensity (category), forward speed, radius of maximum winds and the tide anomaly were varied for each hypothetical track. According to these scenarios, the potential storm surge and associated inundation threat were computed. Subsequently, the Maximum Envelope of Water (MEOW) and the Maximum of the MEOWs (MOMs) were calculated to assess the flood hazard induced by tropical cyclones under varying conditions. In addition, for each MOM, the socioeconomic vulnerability aspects were taken into account in order to assess the hurricane flood risk for the states of Yucatan and Campeche. Results show that the most vulnerable areas are the surroundings of Terminos lagoon, Campeche City and its neighboring areas in the state of Campeche. For Yucatan, the towns located in the Northwest (Celestun, Hunucma and Progreso) and the eastern part of the state presented the highest risk values. The methodology used in this study can be applied to other coastal zones of Mexico as well as places with similar attributes. Furthermore, the MEOW and MOM are very useful as a decision-making tool for prevention, preparedness, evacuation plans, mitigation of the flood hazard and its associated risk, and also for insurance companies. [ABSTRACT FROM AUTHOR]

Identifying flood risk-prone areas in the regions of extreme aridity conditions is essential for mitigating flood risk and rainwater harvesting. Accordingly, the present work is addressed to the assessment of the flood risk depending on spatial analytic hierarchy process of the integration between both Remote Sensing Techniques (RST) and Geographic Information Systems (GIS). This integration results in enhancing the analysis with the savings of time and efforts. There are several remote sensing-based data used in conducting this research, including a digital elevation model with an accuracy of 30 m, spatial soil and geologic maps, historical daily rainfall records, and data on rainwater drainage systems. Five return periods (REPs) (2, 5, 10, 25, 50, 100, and 200 years) corresponding to flood hazards and vulnerability developments maps were applied via the weighted overlay technique. Although the results indicate lower rates of annual rainfall (53-71 mm from the southeast to the northwest), the city has been exposed to destructive flash floods. The flood risk categories for a 100-year REP were very high, high, medium, low, and very low with 17%, 41%, 33%, 8%, and 1% of total area, respectively. These classes correspond to residential zones and principal roads, which lead to catastrophic flash floods. These floods have caused socioeconomic losses, soil erosion, infrastructure damage, land degradation, vegetation loss, and submergence of cities, as well life loss. The results prove the GIS and RST effectiveness in mitigating flood risks and in helping decision makers in flood risk mitigation and rainwater harvesting. [ABSTRACT FROM AUTHOR]

Many parts of Upper Egypt as Sinai and Red Sea areas were hit by severe flash floods since 1976. Wadi Qena is considered one of the most watersheds that suffers from floods in Red Sea area. It was recorded by the General Authority for Roads, Bridges & Land Transport (GARBLT) that the flash flood destructive effect always occurs on El-Geesh–Hurghada Road which is located in the southern part of Wadi Qena watershed. The current study investigates the assessment of endangered areas in Wadi Qena watershed based on a suggested concept of multi-method approach which is a combination of morphometric ranking method and El-Shamy approach. The morphometric analysis is applied using set of parameters which are classified into three categories: basin geometry, drainage network and texture, and relief parameters. For basin geometry, the considered parameters are the watershed area (A), elongation ratio (Re), circularity ratio (Rc), form factor (Ff), and compactness coefficient (Cc). For drainage network and texture parameters, stream frequency (F), texture ratio (Rt), length of overland flow (Lo), and drainage density (D) parameters are considered. For relief parameters, the parameters are mean basin slope (Sm), relief ratio (Rr), and ruggedness number (Rn). A filtration process for the above twelve parameters is considered for reducing the number of parameters by omitting the parameters which have inverse effect on the flood severity of the study area. It is concluded that six parameters have a direct effect on sub-basin hazardous including A, D, Lo, Sm, Rr, and Rn. Sensitivity analysis is concerned for ranking the selected parameters by their significant parameters in assessing the most hazard sub-basins. An overall assessment map is constructed showing the hazard degrees of the sub-basins. The constructed map concludes that the sub-basins are divided into moderate and high hazard ones. Moreover, the results show that the high hazard degree sub-basins are concentrated in the middle and east of the watershed with a percentage of 18.5% of the total area. The developed overall assessment map can be used for assessment and mentoring processes of flood mitigation and planning. [ABSTRACT FROM AUTHOR]

Flood, a perennial phenomenon mainly in low lying deltaic areas and flood plain regions, can be viewed as beneficial for enhancing soil fertility and agricultural production, but also as one of the most destructive natural hazard endangering human life, property, economy and environment. Floods in lower Gangatic flood plain are annual event, especially Malda district of West Bengal has been severely affected by flood over the years by the mighty Ganga and its left bank tributaries during high stage of flow. Assessing risk from flood using composite hazard and vulnerability index has been a widely recognized tool which acts as an important element for formulation of policies aiming at flood risk reduction. The present investigation is an endeavor to assess risk due to flooding using analytical hierarchical processes incorporating flood hazard elements and vulnerability indicators in geographical information system environment. Flood hazard map has been prepared using selected morphological and hydrometerological elements whereas the vulnerability map has been produced using demographic, socio-economic and infrastructural elements. Finally, risk map of flood has been developed compiling both the above-mentioned aspects. The analysis concluded that the northern and western parts of the district are most risk prone from flood hazard than the eastern part. [ABSTRACT FROM AUTHOR]

The assessment of vulnerability provides valuable knowledge in the risk assessment steps of a risk governance process. Given the multiscale, multilevel, and multisectorial aspects of flood risk, the diversified entities that directly and indirectly intervene in risk management require specific outputs from the assessment studies. Urban areas in estuarine margins are particularly exposed and vulnerable to flooding. Such interface conditions are found in the Old City Centre of the Seixal, located in the Tagus estuary, Portugal. Here, two distinct methodologies were applied for the assessment of territorial vulnerability. A regional, lower-scale, methodology explores the application of the statistical procedure based on the SoVI® at the statistical block level. A second, local and higher-scale, methodology is based in data collected through field matrices at the building and statistical sub-block level. Comparison of results revealed that the lower-scale assessment provides information on the vulnerability drivers at the regional and municipal level. Nevertheless, only at a higher-scale, it is possible to characterize and differentiate the smaller geographical units of analysis that compose the Old City Centre of Seixal. The lower-scale vulnerability assessment allows a strategic response, based on adaptation measures such as spatial planning, institutional capacity building and public awareness. The local level assessment provides more accurate knowledge to support local emergency planning and the allocation of operational and material resources at the urban level. Nevertheless, rather than antagonistic, both models can be considered as complementary, having in mind the requirements of an holistic flood risk governance model. [ABSTRACT FROM AUTHOR]

Astronomical high tides and meteorological storm surges present a combined flood hazard to communities and infrastructure. There is a need to incorporate the impact of tide-surge interaction and the spatial and temporal variability of the combined flood hazard in flood risk assessments, especially in hyper-tidal estuaries where the consequences of tide and storm surge concurrence can be catastrophic. Delft3D-FLOW is used to assess up-estuary variability in extreme water levels for a range of historical events of different severity within the Severn Estuary, southwest England as an example. The influence of the following on flood hazard is investigated: (i) event severity, (ii) timing of the peak of a storm surge relative to tidal high water and (iii) the temporal distribution of the storm surge component (here in termed the surge skewness). Results show when modelling a local area event severity is most important control on flood hazard. Tide-surge concurrence increases flood hazard throughout the estuary. Positive surge skewness can result in a greater variability of extreme water levels and residual surge component, the effects of which are magnified up-estuary by estuarine geometry to exacerbate flood hazard. The concepts and methodology shown here can be applied to other estuaries worldwide. [ABSTRACT FROM AUTHOR]

Floods may lead to destruction of property, to damage to the environment and ultimately to loss of lives. Although it is not possible to avoid them, they are enhanced by human activities that increase the probability of occurrence of these natural events. Preliminary flood risk assessment and determination of areas of potential significant flood risk is mandatory according to the European Floods Directive (2007). In order to meet the established legislation, a methodology was developed that couples two modelling approaches: the Hydrological Simulation Program—FORTRAN (HSPF) and IBER. A target watershed, with complex orography and known to be vulnerable to flood hazards, is selected: the Vez River (northern Portugal). The performance of the HSPF model, driven by a climate gridded dataset, was assessed, followed by the reconstruction of the flow rate in the catchment for the period from 1950 to 2015. The results hint at an agreement between simulated and observed daily flow rates, with high coefficient of determination value and of the Nash-Sutcliffe coefficient of efficiency (> 0.7 daily timescale). A satisfactory performance was also found in reproducing flood peak events. An average deviation of 10% was found between observed and simulated flood peaks. The output of HSPF was subsequently used to drive IBER, thus determining flood hazard areas for a 10, 50 and 100-year return periods. The methodology presented here provides basic tools for decision-makers to evaluate hydrologic responses to climate data, namely the determination of flood hazard maps, but also risk assessment, water management, environmental protection and sustainability. [ABSTRACT FROM AUTHOR]

Flood disasters and its consequent damages are on the rise globally. Pakistan has been experiencing an increase in flood frequency and severity along with resultant damages in the past. In addition to the regular practices of loss and damage estimation, current focus is on risk assessment of hazard-prone communities. Risk measurement is complex as scholars engaged in disaster science and management use different quantitative models with diverse interpretations. This study tries to provide clarity in conceptualizing disaster risk and proposes a risk assessment methodology with constituent components such as hazard, vulnerability (exposure and sensitivity) and coping/adaptive capacity. Three communities from different urban centers in Pakistan have been selected based on high flood frequency and intensity. A primary survey was conducted in selected urban communities to capture data on a number of variables relating to flood hazard, vulnerability and capacity to compute flood risk index. Households were categorized into different risk levels, such as can manage risk, can survive and cope, and cannot cope. It was found that risk levels varied significantly across the households of the three communities. Metropolitan city was found to be highly vulnerable as compared to smaller cities due to weak capacity. Households living in medium town had devised coping mechanisms to manage risk. The proposed methodology is tested and found operational for risk assessment of flood-prone areas and communities irrespective of locations and countries. [ABSTRACT FROM AUTHOR]

This article outlines a conceptual model and comparatively applies it to results from environmental justice (EJ) studies of flood risk in the Miami, Florida, and Houston, Texas, metropolitan areas. In contrast to most EJ studies of air pollution, which have found that socially vulnerable groups experience disproportionate risk, distributive EJ studies of flooding reveal inconsistent findings regarding the relationship between social vulnerability and flood exposure. Counterintuitively (from a conventional EJ perspective), some pre-flood EJ studies have found that socially advantaged people experience the highest residential exposure to flood risks. To integrate those anomalous findings within an EJ perspective, our conceptual model focuses on (1) the differential capacities of social groups to deploy/access protective resources for reducing the threat of loss, even while they reside amid flood-prone environments, and (2) both flood hazards and water-based benefits. Application of this model in Miami reveals that environmental injustices materialize as socially privileged groups expose themselves to residential flood risks by seeking coastal amenities, as the costs of mitigating risks are conveyed to the broader public; in the process, socially vulnerable residents are relegated to areas with air pollution and/or inland flood risks, where they experience constrained access to protective resources and coastal amenities. Findings from Houston better align with conventional EJ expectations—with flood zones disproportionately inhabited by socially vulnerable people—because many coastal lands there are used by petrochemical industries, which produce major residential-environmental disamenities. Results underscore the need to consider protective resources and locational benefits in future empirical research on the EJ implications of flood hazards. [ABSTRACT FROM AUTHOR]

Floods are one of the major threats to low-lying coastal lagoons, affecting people, socio-economic activities and ecosystem services. This work proposes a methodology to assess present and future flood hazard and risk in west-boundary low-lying coastal lagoons, using the Ria de Aveiro (Portugal) as case study. A multidisciplinary approach supported on Source-Pathway-Receptor-Consequence model combined with a GIS-based multi-criteria analysis was developed and applied. This comprised the following steps: (1) definition of present and future climate scenarios associated with oceanic, fluvial and combined events, combining sea levels and river discharges for different return periods; (2) characterization of flooding pathway through hydrodynamic modelling; (3) assessment of flood hazard combining flood depth and probability from hydrodynamic simulations; (4) assessment of flood risk calculating the adverse consequences on assets exposed to flood hazard. Results highlight that endangered regions are strongly dependent on the floods origin: oceanic floods threaten settlements and economic activities located along the margins of the lagoon main channels as well as habitats in the lagoon central area; fluvial floods endanger the river's mouth adjacent areas causing damage in restricted settlements, economic activities and farmland habitats; the combined floods also threaten the margins adjacent to the transition zones. For future scenarios, it is predicted the flood risk increase/decrease for oceanic/fluvial events, as a consequence of mean sea level rise/river discharges reduction predicted for the region. Finally, this work demonstrated the value of the methodology proposed and its potential for flood risk analysis, supporting the decision-making process underlying the flood risk management. [ABSTRACT FROM AUTHOR]