Impact Of Floods Research Articles

Role of income and government responsiveness in reducing the death toll from floods in Indian states

Floods are the most commonly occurring natural disasters in India due to India’s unique geographical location and socioeconomic conditions. Frequent flooding causes enormous loss of human lives and damage crops and public utilities. Furthermore, floods adversely affect economic development and increase the government's financial burden by increasing spending on various disaster mitigation measures. Recent empirical literature based on cross-national comparisons shows that disaster fatalities and damages are monotonically decreasing in per capita income. We challenge this view on the monotonic negative relationship between income and flood damages. We examine the non-monotonic (inverted U-shaped) relationship between per capita income and flood impact in terms of deaths, people affected, and damages due to floods in 19 major Indian states from 1980 to 2011, using Poisson and Tobit estimation methods. In particular, deaths and the population affected by floods increase with a turning point of income up to 882 US$ and 578 US$, respectively, and diminishes thereafter. Our results confirm an inverted U-shaped relationship between income and fatalities and the population affected by floods. In addition to income, we argue that government responsiveness plays an essential role in mitigating the risk of floods. We employ the fixed-effect Poisson estimation method to examine the government's role in protecting people against disaster risk, focusing on regional differences in India. Deaths from floods remain non-linear and follow the inverted U-pattern with respect to government responsiveness. However, the effect of government responsiveness on flood fatalities and flood damages is statistically insignificant. Our results further suggest that high-income states experience a lower death toll from floods. The high-income (rich) states are capable of incurring a higher threshold level of income and higher natural calamity expenditure to reduce flood fatalities and protect the population affected by floods than the low-income (poor) states. The poor states have minimal resources and face severe financial constraints to reduce the death toll from floods. From the perspective of public policy, the poor states, in particular, require an increase in income, better governance, and effective disaster management policies to mitigate flood impact.

Influences of a debris flow disaster chain on buildings in remote rural areas, Southwest China

The magnitude and frequency of mountain hazards will continue to increase because of climate change especially in rural mountainous areas, which have not received much attention. In this article, a debris flow disaster chain in Southwest China caused damage to buildings along the river bank was investigated. The disaster chain included a debris flow, river blockage, lake formation, and an outbreak flood, and this study further investigated the disaster-related losses in downstream villages. Based on the characteristics of failed buildings, three structural types were identified, while the functions of undamaged buildings were affected by flooding or siltation by sediments. In addition, the building layout and riparian vegetation zone influenced the blockage effect, which resisted the flood impact and provided protection to rear buildings. Moreover, this disaster changed the river topography, the studied reach changed from a V shape to a wide–shallow shape, the appreciably affected river length was 6270 m, and the gully bed was noticeably raised 15–20 m. Furthermore, the flood control standard of a 50-year return period was recommended for reference, despite the limitations of these suggestions, we hope that this study attracts the attention of researchers on disaster prevention and mitigation in remote rural areas.

Assessing the 2022 Flood Impacts in Queensland Combining Daytime and Nighttime Optical and Imaging Radar Data

In the Australian summer season of 2022, exceptional rainfall events occurred in Southeast Queensland and parts of New South Wales, leading to extensive flooding of rural and urban areas. Here, we map the extent of flooding in the city of Brisbane and evaluate the change in electricity usage as a proxy for flood impact using VIIRS nighttime brightness imagery. Scanning a wide range of possible sensors, we used pre-flood and peak-flood PlanetScope imagery to map the inundated areas, using a new spectral index we developed, the Normalized Difference Inundation Index (NDII), which is based on changes in the NIR reflectance due to sediment-laden flood waters. We compared the Capella-Space X-band/HH imaging radar data captured at peak-flood date to the PlanetScope-derived mapping of the inundated areas. We found that in the Capella-Space image, significant flooded areas identified in PlanetScope imagery were omitted. These omission errors may be partly explained by the use of a single-date radar image, by the X-band, which is partly scattered by tree canopy, and by the SAR look angle under which flooded streets may be blocked from the view of the satellite. Using VIIRS nightly imagery, we were able to identify grid cells where electricity usage was impacted due to the floods. These changes in nighttime brightness matched both the inundated areas mapped via PlanetScope data as well as areas corresponding with decreased electricity loads reported by the regional electricity supplier. Altogether we demonstrate that using a variety of optical and radar sensors, as well as nighttime and daytime sensors, enable us to overcome data gaps and better understand the impact of flood events. We also emphasize the importance of high temporal revisit times (at least twice daily) to more accurately monitor flood events.

Impact of unseasonable flooding on women's food security and mental health in rural Sylhet, Bangladesh: a longitudinal observational study

BackgroundClimate change will lead to more frequent and intensive flooding. In April, 2017, unseasonably early flooding led to the inundation of low-lying cropland before the rice harvest in northeastern Bangladesh. We describe coping strategies and quantify short-term and medium-term effects of flooding events on food security and depressive symptoms of women. MethodsThis observational study is part of the cluster-randomised Food and Agricultural Approaches to Reducing Malnutrition trial (FAARM; NCT02505711). Women self-reported flooding exposure on behalf of their households when surveyed (approximately 6 months after the event). Remote sensing analysis was used to detect the extent of the flooding. We collected data on household food security at baseline, depressive symptoms 4–5 months before the flooding, and coping strategies immediately after the event. We followed up on these outcome measurements for depressive symptoms and food security for up to 2·5 years after the flooding event. We used multilevel regression adjusting for intervention allocation and pre-flooding measures to quantify the flood's effect on household food security and women's mental health. FindingsThe FAARM trial included 2700 young women in 96 settlements in rural Sylhet, Bangladesh. 1335 (56%) of 2405 women reported that their household being greatly affected, with many losing a large part of their rice harvest. Borrowing money with interest was the most common coping strategy, with households paying back on average 1·5 times the borrowed amount. Greatly affected households had higher odds of food insecurity, with a decreasing effect with increasing time after the flood (odds ratio: 2·4 [p<0·0001] 0·5 years after; 1·6 [p<0·0001] 2·0 years after]; and 1·3 [p=0·012] 2·5 years after). Women in such households also had 1·45 times higher odds of depression (p=0·0001) 2·5 years after the flooding event. InterpretationThe 2017 flooding event negatively affected food security and the mental health of women in rural Sylhet, Bangladesh, and few affected women received formal government support. To reduce the impact of future floods, livelihood adaptations and expansion of financial protection programmes are essential measures to pursue. FundingGerman Federal Ministry for Education and Research (Berlin, Germany) and UK Department for International Development (London, UK).

Resilience benefit assessment for multi-scale urban flood control programs

• Resilience benefit analysis framework proposed for urban flood control programs. • Relationship between urban flood control system resilience and multi-scale urban flood control programs is determined. • This framework is based on a Storm Water Management Model. • Entropy & Technique for Order Preference by Similarity to Ideal Solution method is used. Urban flood frequencies have increased and will continuously increase due to global climate change and rapid urbanization, causing enormous economic problems and social impact. Resistant strategies are no longer the best option for disaster mitigation. Improving cities' resilience to external disruptions is becoming a more important method for mitigating the impact of urban flooding. However, there are relatively little research has been conducted on the resilience of urban flood control systems. The introduction of the concept of resilience can provide a new way of thinking for urban flood control research, which can help to understand the coping process of the system during heavy rainfall, emphasizing the absorption, resistance, and recovery stages to improve the system's adaptability to the changing environment and effectively alleviate the pressure of urban flooding. This study discusses the impact of the design and configuration of urban flood control programs on the resilience of the system under heavy rainfall. Moreover, the resilience benefit is presented to quantify the phased process of system resilience capacity for measuring the quantitative relationship between programs and system resilience. Finally, the unit annual average cost of the program is combined with the resilience benefit to make decisions and ensure that cities are effectively reducing the risk of urban flooding with the optimal alternatives. The proposed framework was applied to Zhangjiagang City, a highly urbanized and densely populated city in China. The results showed that (1) during the same rainfall event, the hydrological indicators characterizing the system’s resilience process (absorption, resistance, and recovery) have distinct weights; (2) rainfall has an effect on the index weight, and the weight fluctuates when the system responds to rainfall in distinct return periods; (3) rainfall return periods can have an impact on a program’s effectiveness in improving the system's resilience at various stages, and the extent to which different programs are affected by the return period varies; and (4) combining large-scale and micro-scale programs improve the resilience of the system more effectively, whereas concentrating on expanding storage volume without raising the water surface rate improves the resilience of the system less effective. This framework can be used to assess the improvements in resilience acquired from various urban flood control program configurations and to assist city planners in selecting the optimal configuration, so assisting in the decision-making process for urban planning and disaster mitigation.

Management of coastal flood impact in rural area (Case study in Sayung District)

Sayung Subdistrict, Demak Regency is a low-lying coastal area prone to coastal flooding. This coastal area’s flood susceptibility is not influenced by a single factor, but by the combined effect of excessive rainfall, the morphological characteristics of coastal areas, and tidal waves. As a reason, the objectives of this study were to (1) map coastal flood-prone areas using a combination of heavy rainfall and tidal waves; (2) determined the extent of inundation; and (3) provide feedback on potential flood-affected area management. The findings indicate inundation has increased by 2.4% per year. Therefore, the evaluation of the mitigation management has to be considered either on local communities’ perspective, regional and national government planning and non-government implementation. Local communities, with or without the assistance of NGO and regional governments, adapt their mitigation strategies to the changing environment, whether through physical, economical, or social approaches. Meanwhile, the regional and national governments’ management will be incorporated into the detailed spatial planning.

Risk Assessment and Impact of Floods on the Transmission of Vector Borne Diseases

Floods are the result of natural disasters in an area due to prolonged continued and heavy rains and are frequently followed by a proliferation of mosquitoes due to the creation of a large number of breeding habitats. In the endemic zones for VBDs, vector mosquito species require special attention for planning immediate control measures as these areas may pose a threat to public health. Natural disasters continue to strike unabated, flash floods due to heavy rains, riverine floods,coastal floods and cloud burst floods. In general, floods are witnessed due to the concentrated spells of heavy rains during the monsoon months and seasonal disturbances. The low lying areas are submerged under water and remain water logged for a long duration. Slowly, the low lying water bodies thus created after receding of flood water, act as a breeding potential source for the vector mosquitoes. Some of the areas receive water from flushing of water from high altitude areas due to heavy rains or melting of ice. There is definite need for public health preparedness and response for the flood affected areas to reduce the transmission of VBDs with proper risk assessment. There are chances for the onset of transmission of VBDs to the population shifted to temporary shelter homes away from homes. Given the situation with the presence of congenial conditions owing to presence of favourable climatic variables for propagation of vectors, pathogens and susceptible population, there are chances of disease outbreaks. Therefore, the risk assessment of the flood affected area with the vulnerable population is essential to make preparedness and response to any onset of VBDs transmission. Disease and vector surveillance are the key elements to be in place for such flood affected areas during and after the floods.

Shoreline protection by the world’s coral reefs: Mapping the benefits to people, assets, and infrastructure

The important role of coral reefs in protecting people, economies and infrastructure is widely acknowledged. Coral reefs are highly effective at reducing wave energy and thereby diminishing the impact of both flooding and erosion in coastal areas. Understanding these benefits, and their spatial distribution, can play a critical role in driving efforts to protect or even restore coral reefs, with critical societal benefits. Simple, high-resolution models were used to generate a global map which suggests that 26 % of the coastline of the world’s coral reef nations receive some protection benefits, and that, over decadal periods some 5.3 million people and $109 billion of GDP are protected by coral reefs. Separate maps show the values at the shore and plot the reefs providing those values. Differences exist between metrics (population, GDP and night-time lights as a metric for infrastructure) raising the importance of considering ecosystem service values with multiple metrics, including non-monetary values. Patterns of protection are highly heterogeneous, however many of the most important areas are adjacent to highly developed shores and many of these receive little or no management attention.

Rare flood scenarios for a rapidly growing high-mountain city: Pokhara, Nepal

Abstract. Pokhara (ca. 850 m a.s.l.), Nepal's second-largest city, lies at the foot of the Higher Himalayas and has more than tripled its population in the past 3 decades. Construction materials are in high demand in rapidly expanding built-up areas, and several informal settlements cater to unregulated sand and gravel mining in the Pokhara Valley's main river, the Seti Khola. This river is fed by the Sabche glacier below Annapurna III (7555 m a.s.l.), some 35 km upstream of the city, and traverses one of the steepest topographic gradients in the Himalayas. In May 2012 a sudden flood caused &gt;70 fatalities and intense damage along this river and rekindled concerns about flood risk management. We estimate the flow dynamics and inundation depths of flood scenarios using the hydrodynamic model HEC-RAS (Hydrologic Engineering Center’s River Analysis System). We simulate the potential impacts of peak discharges from 1000 to 10 000 m3 s−1 on land cover based on high-resolution Maxar satellite imagery and OpenStreetMap data (buildings and road network). We also trace the dynamics of two informal settlements near Kaseri and Yamdi with high potential flood impact from RapidEye, PlanetScope, and Google Earth imagery of the past 2 decades. Our hydrodynamic simulations highlight several sites of potential hydraulic ponding that would largely affect these informal settlements and sites of sand and gravel mining. These built-up areas grew between 3- and 20-fold, thus likely raising local flood exposure well beyond changes in flood hazard. Besides these drastic local changes, about 1 % of Pokhara's built-up urban area and essential rural road network is in the highest-hazard zones highlighted by our flood simulations. Our results stress the need to adapt early-warning strategies for locally differing hydrological and geomorphic conditions in this rapidly growing urban watershed.

Assessment of Flooding Impact on Water Supply Systems: A Comprehensive Approach Based on DSS

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.

Assessment of flood vulnerability of riverine island community using a composite flood vulnerability index

The devastating impact of flooding is gradually increasing worldwide including riverine islands of Bangladesh due to climate change issue. Riverine islands and coastal communities are the primary victims due to their geographical position. The riverine islands (char) of Bangladesh are frequently flooded, necessitating context-specific flood management policies and actions that require an in-depth investigation of household vulnerability level. Therefore, this study assesses the vulnerability level of riverine island dwellers to flooding. Data were collected from 384 household heads living in geographically isolated char areas. A context-specific composite flood vulnerability index was developed under the IPCC framework. The results reveal that all households are vulnerable to flooding and are poorly able to cope with its adverse effect. Households living near the mainland have a somewhat more adaptive capacity than distant households. Flood vulnerability is mainly determined by char households' flood perception, damage, and access to food, water and health resources during flooding. Riverbank erosion, recurrent floods, a lack of employment, and limited access to essential public services were also identified as the primary socio-economic and natural causes of flood vulnerability. To decrease the livelihood risk and promote char dwellers’ resilience, a char-based policy plan with both a short- and a long-term focus is required.

Predicting temporal and spatial variability in flood vulnerability and risk of rural communities at the watershed scale

Due to land-use and hydrology changes, people are constantly exposed to floods. The adverse impact of floods is greater on vulnerable populations that disproportionately inhabit flood-prone areas. This paper reports a comprehensive study on flood vulnerability of flood prone areas in residential areas of the Tajan watershed, Iran in two periods before 2006 and after 2006. Flood prone area were determined by the random forest (RF) and K-nearest neighbor (KNN) machine learning methods. To reduce time and cost, the vulnerability was assessed only in areas with very high flood hazard using 4 main criteria (social, policy, economic, infrastructure), 40 items, and 210 questionnaires across 40 villages. Independent t-test, Kruskal-Wallis, and paired t-test were used for statistical analysis of questionnaire data. The results of machine learning models (MLMs) showed that the RF model with AUC = 0.92% is more accurate in determining flood prone areas. The results of paired t-test showed that the three criteria of social (mean P1 = 2.97 and P2 = 3.35), infrastructure (mean P1 = 2.88 and P2 = 3.25), and policy (mean P1 = 3.02 and P2 = 3.50) had significant changes in both periods. The Kruskal-Wallis test also revealed the mean of all four criteria in both periods and all sub-watersheds, except three sub-watersheds 10 (Khalkhil village), 19 (Tellarem and Kerasp villages), and 23 (Dinehsar and Jafarabad), had a significant difference. The results of the t-test also showed a decrease in vulnerability in the second period (before 2006) compared to the first period (after 2006), so the number of sub-watersheds in the very high vulnerability class was more in the first period than in the second period. A vulnerability map was developed using three factors of risk zone area, area of each sub-watershed, and population of each sub-watershed.

Impact of floods and river-bank erosion on the riverine people in Manikchak Block of Malda District, West Bengal.

Floods and river-bank erosion are the most frequent natural hazards in India, specifically in the deltaic regions. In West Bengal, floods and river-bank erosion predominantly affect Malda district as it is located in the moribund part of the Bengal delta. This article studies the recent trend of shifting course of the River Ganga and the effects of floods and consequent river-bank erosion on livelihoods of the residents of chars [The chars (called Diara in the upper reaches of the Gangetic plains) are virgin, low-lying river islands and sand bars occurring in the plains, particularly the deltaic parts of rivers (Lahiri-Dutt and Samanta, South Asia: J South Asia Stud 30:327–350, 2007).] and river-bank areas of Manikchak block in the Malda district. Around 300 sample households were selected by random stratified sampling technique from four gram panchayats of Manikchak block. Both primary and secondary data have been used. After analysing satellite images from the year 1973 to 2018, it has been observed that the River Ganga continues to shift eastwards and is eroding villages one after another. Inhabitants face multidimensional obstacles to run their households. Large numbers of people are displaced every year due to loss of land. Failure in facilitating the required assistance in the form of alternative spaces for resettlement and other disaster-mitigating public support systems against these hazards would make it impossible for the deplorable condition of the vulnerable people to improve.

Innovative Vulnerability and Risk Assessment of Urban Areas against Flood Events: Prognosis of Structural Damage with a New Approach Considering Flow Velocity

The floods in 2002 and 2013, as well as the recent flood of 2021, caused billions Euros worth of property damage in Germany. The aim of the project Innovative Vulnerability and Risk Assessment of Urban Areas against Flood Events (INNOVARU) involved the development of a practicable flood damage model that enables realistic damage statements for the residential building stock. In addition to the determination of local flood risks, it also takes into account the vulnerability of individual buildings and allows for the prognosis of structural damage. In this paper, we discuss an improved method for the prognosis of structural damage due to flood impact. Detailed correlations between inundation level and flow velocities depending on the vulnerability of the building types, as well as the number of storeys, are considered. Because reliable damage data from events with high flow velocities were not available, an innovative approach was adopted to cover a wide range of flow velocities. The proposed approach combines comprehensive damage data collected after the 2002 flood in Germany with damage data of the 2011 Tohoku earthquake tsunami in Japan. The application of the developed methods enables a reliable reinterpretation of the structural damage caused by the August flood of 2002 in six study areas in the Free State of Saxony.

A coupled model for macroscopic behavior of crowd in flood induced evacuation

Floods are regarded as critical disasters that often lead to catastrophic situations and provoke potential injuries and/or fatalities. The consequences of the flood on the exposed population can be realized by exploring the complex behavioral phenomena of the crowd in interaction with the flood hazard. A profound understanding of the time–space distribution of evacuation patterns and vulnerability in floodwater would help in developing a robust risk reduction strategy and mitigating the flood impact. This paper presents a model that combines a macroscopic description of a crowd evacuation model with a hydrodynamic model of flood inundation described by a two-dimensional depth-averaged Shallow Water Equation (SWE), considering two-way dynamic coupling to study the collective behavior of the crowd in a flooded evacuation scenario. Behavioral rules, such as reduced motion in floodwater, route choice through safe areas, and stress due to perception of danger in threatening flood, are imposed to account for the evacuees’ reaction to floodwater. Moreover, the disruption in free flood propagation due to the pedestrians’ presence in the floodplain has also been modeled. The pedestrian model is solved using a third-order Weighted Essentially Non-Oscillatory (WENO3) scheme, and the hydrodynamic model is numerically handled using a high-resolution Godunov type scheme with HLLC Riemann solver. The potential of the developed model is illustrated through two designed hypothetical test cases, which include the crowd evacuation from a supermarket area exposed to a sudden flood.

Can green roofs help with stormwater floods? A geospatial planning approach

Increasing urbanization, impervious space, and the impact of climate change are threatening the future of cities. Nature-based solutions, specifically urban green infrastructures, are seen as a sustainable strategy to increase resilience against extreme weather events, including the escalating occurrence of stormwater runoff flooding. Consequently, urban planners and decision-makers have pushed their efforts toward implementing green infrastructure solutions to reduce the impact of stormwater floods. Among others, green roofs help store water and decrease stormwater runoff impacts on a local scale. This research aims to investigate the effect of surface permeability and green roof implementation on reducing stormwater flooding and subsequently provide urban planners with evidence-based geospatial planning recommendations to improve urban resilience in Helsinki. First, we modeled the current impact of stormwater flooding using the Arc-Malstrom model in Helsinki. The model was used to identify districts under high stormwater flood risk. Then, we zoomed in to a focus area and tested a combination of scenarios representing four levels of green roof implementation, two levels of green roof infiltration rates under 40-, 60-, 80-, 100 mm precipitation events on the available rooftops. We utilized open geographic data and geospatial data science principles implemented in the GIS environment to conduct this study. Our results showed that low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1 %. In contrast, the maximum green roof scenario decreased most of the average flood depth (13 %) and reduced the number of vulnerable sites. The proposed methodology can be used for other cities to develop evidence-based plans for green roof implementations.

Development and application of flood impact maps under climate change scenarios: A case study of the Yilan area of Taiwan

Flooding is the main disaster type in Taiwan and is usually caused by typhoons and heavy rainfall. To understand the flood impacts in Taiwan caused by increasing rainfall due to global warming, this study adopts a high-resolution atmospheric model (HiRAM) under the representative concentration pathway (RCP) 8.5 scenario to project future changes in flood impact. For the flood simulation, the SOBEK flood model was used to determine the maximum accumulated flooding depth and flood probability in the two periods of the present and the middle of the 21st century. Yilan County, one of the most flood-prone areas in Taiwan, was chosen as a demonstration case for the development of flood impact maps. According to the results of flood map application, flooded areas were predicted to increase in the middle period of the 21st century due to increasing rainfall, especially in paddy fields, maricultural farms, and stock farms. From the base period to the middle of the 21st century, the area of flooding impacts was projected to increase from 24% to 40% in paddy fields, from 9% to 15% in maricultural farms, and from less than 1% to 9% in stock farms. These results show that the development of flood maps can help elucidate the actual impacts of climate change in Taiwan and serve as a scientific basis for adaptation actions.

Coastal Flood Risks and the Business Community: Stakeholders’ Perception in Malta

Resilience of coastal communities is increasingly required to adjust to the effects of climate change and its coast-related threats. Climate change is a major global threat to the environment, economy, and health of urban coastal lowlands. Flooding risks from both rising sea levels and increases in the frequency and severity of storm surges are considered to be amongst the most threatening consequences associated with climate change. The aim of this study was to assess the levels of socio-economic preparedness of low-lying urbanized towns in Malta for the impacts of coastal flooding through the triangulation of stakeholders’ participation from three sectors: the business community, local councils, and specialized experts from the governmental and private sectors. The study also included field collection of elevation data for each locality to capture the businesses’ distribution in relation to their height above sea level along the urban waterfront. One-way analysis of variance and NVivo were used to test and compare the business owners’ responses and the experts’ feedback, respectively. The main findings from the business community suggest that there are no long-term contingency plans or strategies in place to address potential flooding impacts from rising sea levels and storm surges, and that the risks of driving owners out of business is high. From the feedback received by the local councils, it was observed that all of them significantly lack the physical and financial resources to effectively manage long-term coastal flooding within their locality, forcing them to completely rely on central government for any future needs caused by the impact of coastal flooding. From a central government perspective, it seems that all interviewed experts operate within a fragmented governance model, and mainly adhere to the set of responsibilities aligned with their respective roles within such a governance model. This evidence of governance disconnect requires more horizontal and vertical integration of cross-sectoral strategies to address coastal flooding, within the broader framework of integrated coastal zone management as established by the Mediterranean ICZM protocol.

Environmental impact assessment of dam-break floods considering multiple influencing factors.

Dam-break floods cause substantial damage to the environment, and evaluating the negative impacts of dam-break floods on the environment (EI) is an important part of flood risk management. EI has been evaluated using various methods with different indices. However, the evaluation results of EI are typically one-sided or inaccurate because of diverse indices and complex influencing factors. A new method was proposed herein to calculate EI with an index system, including geomorphic changes (GC), water pollution (WP), plant biomass loss (PB), and biodiversity loss (BL). Eight factors that influence EI were sorted out, namely, erosion or deposition depth, non-point source (NPS) and point source (PS) pollution, plant biomass, species richness, plant height, and flood depth, velocity, and duration. After combining the proposed damage functions to calculate the influence of flood depth, velocity, and duration, and plant height on the environment, methods to calculate GC, WP, PB, BL, and EI were proposed. A dam-break flood scenario for Luhun Reservoir was used to verify the method. The results showed that (1) the trend in EI was similar to that in geomorphic changes in the inundated area and seriously affected by PS in local areas, (2) the average EI of woodland was the highest, while that of towns was the slowest, and (3) GC and WP contributed 93.7% of EI in the entire inundated area. This study summarized the complex impacts of dam-break floods on the environment from four aspects and proposed a method to quantify the overall impact of dam-break floods on the environment. The evaluation model could evaluate the impact of floods on the environment accurately, presenting the results on a flood inundation map. This provides a scientific basis for evaluating flood consequences and managing flood risk.

Analyzing the Impact of Floods on Vehicular Mobility along Urban Road Networks Using the Multiple Centrality Assessment Approach

Analyzing the Impact of Floods on Vehicular Mobility along Urban Road Networks Using the Multiple Centrality Assessment Approach