Flood Risk Reduction Measures Research Articles

Integrated assessment for groundwater quality and flood vulnerability in coal mining regions.

Coal mining activities greatly damage water resources, explicitly concerning water quality. The adverse effects of coal mining and potential routes for contaminants to migrate, either through surface water or infiltration, into the groundwater table. Dealing with pollution from coal mining operations is a significant surface water contamination concern. Consequently, surface water resources get contaminated, harming nearby agricultural areas, drinking water sources, and aquatic habitats. Moreover, the percolation process connected with coal mining could alter groundwater quality. Subsurface water sources can get contaminated by toxins generated during mining activities that infiltrate the soil and reach the groundwater table. The aims of this study are the creation of models and the provision of proposals for corrective measures. Twenty-five scenarios were simulated using MODFLOW; according to the percolation percentage and contamination, 35% of the study area, i.e., the middle of the research area, was the most affected. About 38.08% of the area around the mining zones surrounding Margherita is prone to floods. Agricultural areas, known for applying chemical fertilizers, are particularly vulnerable, generating a risk of pollution to surrounding water bodies during flooding. The outputs of this research contribute to identifying and assessing flood-vulnerable regions, enabling focused measures for flood risk reduction, and strengthening water resource management.

Merging modelled and reported flood impacts in Europe in a combined flood event catalogue for 1950–2020

Abstract. Long-term trends in flood losses are regulated by multiple factors including climate variation, demographic dynamics, economic growth, land-use transitions, reservoir construction and flood risk reduction measures. The attribution of those drivers through the use of counterfactual scenarios of hazard, exposure or vulnerability first requires a good representation of historical events, including their location, their intensity and the factual circumstances in which they occurred. Here, we develop a chain of models that is capable of recreating riverine, coastal and compound floods in Europe between 1950 and 2020 that had a potential to cause significant socioeconomic impacts. This factual catalogue of almost 15 000 such events was scrutinized with historical records of flood impacts. We found that at least 10 % of them led to significant socioeconomic impacts (including fatalities) according to available sources. The model chain was able to capture events responsible for 96 % of known impacts contained in the Historical Analysis of Natural Hazards in Europe (HANZE) flood impact database in terms of persons affected and economic losses and for 81 % of fatalities. The dataset enables the study of the drivers of vulnerability and flood adaptation due to a large sample of events with historical impact data. The model chain can be further used to generate counterfactual events, especially those related to climate change and human influence on catchments.

Socio-Economic Vulnerability to Potential Flood in Tamakoshi River in Nepal

Tamakoshi, a transboundary river flowing from Tibet, China to Nepal has experienced several disastrous flash floods resulting in the loss of lives, infrastructures, settlements, lands, and other assets. Many households, populations, and public and private properties such as houses, land, roads, bridges, etc. are likely to be affected by the potential flash floods. This study discusses the occurrence of flash floods, losses and damages from such floods in the past, and socio-economic vulnerability to potential flash floods. It further discusses the preparedness and response activities and identifies the measures for flood risk reduction. The methods adopted for data collection included observation, household surveys, and focus group discussions. The villages selected for detailed study are Gongarkhola, Jagat, Jamune, Bhorle, and Sigati bazaar, identified as the most vulnerable settlements along the Tama Koshi River. It is found that flash floods and high-intensity precipitation occur frequently in the study area resulting in loss of life and properties, and people and properties are exposed to the potential flash floods. Local people are still feeling vulnerable to such flash floods. The government authorities alone are not able to achieve greater success in carrying out preparedness and response activities for flood risk reduction without the active involvement and participation of the vulnerable communities. Development and effective implementation of land-use guidelines and building codes, watershed management, early warning systems, and networking among the people residing across the river are some of the activities identified to reduce flood risk. Although people have a good understanding and knowledge about floods and their occurrences, they pay less attention to preparedness and mitigation. It is also concluded that structural measures alone are not sufficient and effective enough for flood risk reduction

Participatory Causal Loop Diagrams Building for Supporting Decision-Makers Integrating Flood Risk Management in an Urban Regeneration Process.

Several modeling tools commonly used for supporting flood risk assessment and management are highly effective in representing physical phenomena, but provide a rather limited understanding of the multiple implications that flood risk and flood risk reduction measures have on highly complex systems such as urban areas. In fact, most of the available modeling tools do not fully account for this complexity-and related uncertainty-which heavily affects the interconnections between urban systems evolution and flood risk, ultimately resulting in an ineffective flood risk management. The present research proposes an innovative methodological framework to support decision-makers involved in an urban regeneration process at a planning/strategic level, accounting for the multi-dimensional implications of flood risk and of different flood risk management strategies. The adopted approach is based on the use of System Thinking principles and participatory System Dynamics modeling techniques, and pursues an integration between scientific and stakeholder knowledge. Reference is made to one of the case studies of the CUSSH and CAMELLIA projects, namely Thamesmead (London), a formerly inhospitable marshland currently undergoing a process of urban regeneration, and perceived as being increasingly vulnerable to flooding. It represents an interesting opportunity for building a replicable modeling approach to integrate urban development dynamics with flood risk, ultimately supporting policy and decision-makers in identifying mitigation/prevention measures and understanding how they could help achieve multi-dimensional benefits (e.g., environmental, social and economic).

Urban flood hazard assessment in Awka metropolis using multi-criteria decision process

Urban flooding is an escalating global threat, and Awka Metropolis in Anambra state Nigeria is no exception. The city's rapid urbanization and inadequate infrastructure have left it increasingly vulnerable to flooding, exacerbated by the impacts of climate change. Anticipated flood effects include disruption of daily life, infrastructure damage, and threats to public safety, necessitating urgent attention. This study presents a comprehensive assessment of urban flood hazards in Awka Metropolis, utilizing an integrated approach combining the Analytical Hierarchy Process (AHP) and Flood Hazard Index (FHI) to gauge the city's flood vulnerability. The primary objectives were to identify key geophysical factors contributing to flooding, categorize these factors by their vulnerability, determine their reliability indices, delineate flood-prone zones, and generate a spatial flood extent map. The methodology encompassed data acquisition, pre-processing, Flood Modeling (evaluating slope, Elevation, Drainage Network, and flow accumulation), the application of Analytical Hierarchy Process, and the utilization of the Flood Hazard Index. The results classified Awka Metropolis into three flood risk zones: high (837.84 hectares, 14.70%), moderate (2182.65 hectares, 38.30%), and low (2678.45 hectares, 46.99%). These findings provide indispensable insights into the distribution of flood hazards across the city, enabling urban planners and authorities to strategically allocate resources, prioritize mitigation initiatives, and formulate targeted flood risk reduction strategies. Importantly, the incorporation of stakeholder input enhances the study's practical relevance and applicability in real-world urban planning and disaster management scenarios. In conclusion, this research offers a robust and multidimensional framework for assessing urban flood hazards in Awka Metropolis. The synergy of the Analytical Hierarchy Process and Flood Hazard Index equips urban planners, policymakers, and disaster management agencies to proactively tackle the mounting urban flooding challenges. The study's outcomes contribute to the development of sustainable flood risk reduction measures, ultimately enhancing the resilience of Awka Metropolis to future flood events.

Flood risk assessment of the population in Afghanistan: A spatial analysis of hazard, exposure, and vulnerability

Flooding is a recurrent and severe natural hazard in Afghanistan, exacerbated by climate change, and poses significant threats to human lives and livelihoods. The country's socioeconomic vulnerabilities make it highly susceptible to the devastating impacts of disasters, resulting in loss of lives, livelihoods, and damage to public and private assets. This study employs a multimethod research approach, combining remote sensing-based flood data analysis with spatial analysis and literature studies, to comprehensively assess flood risk by considering hazard, exposure, and vulnerability indicators. Specifically, a 25-year return flood event was used to examine flood risk for the exposed population. The framework proposed by the IPCC in 2014 was adopted to define flood risk, encompassing hazard, exposure, and vulnerability components. The findings reveal that provinces located near major river basins, particularly in the southern, northern, and northeastern regions, experience the highest flood risk. Notably, the provinces of Nimroz and Helmand in the southern region exhibit pronounced risk index values of 0.20 and 0.10, with a highly exposed population of 36% and 15%, respectively, and vulnerability index values of 0.57 and 0.62. Similarly, in the northern and northeastern regions, the provinces of Jawzjan and Kunduz also display elevated risk levels, each with a risk index value of 0.11, characterized by highly exposed populations of 21% and 18%, respectively, and vulnerability index values of 0.53 and 0.57. This multi-method approach provides valuable insights into the spatial distribution of flood risk and the drivers of population exposure, assisting policymakers and decision-makers in formulating effective flood risk reduction strategies through targeted flood vulnerability and risk reduction measures.

Challenges for Flood Risk Reduction in Poland’s Changing Climate

Floods are the main natural disaster in Poland, and the risk of both fluvial and pluvial floods is serious in the country. Pluvial floods are on the rise in the changing climate, particularly in increasingly sealed urbanized areas. In this paper, we examine the changes in flood risk in Poland, discussing the mechanisms, observations, projections and variability. Next, we discuss flood risk management in the country, including specific issues related to urban and rural areas and the synergies between flood and drought risk reduction measures. We identify and assess the weaknesses of the existing flood risk management plans in Poland for the first planning period 2016–2021 and for the second planning period 2022–2027. We find the level of implementation of plans in the former period to be very low. Many planned measures do not have much to do with flood risk reduction but are often linked to other objectives, such as inland navigation. The plans contain numerous small measures, which come across as inapt and economically ineffective solutions. We specify policy-relevant recommendations for necessary and urgent actions, which, if undertaken, could considerably reduce flood risk. We also sketch the way ahead for flood risk management in Poland within the timeframe of the implementation of plans for 2022–2027 and the next regular update of plans for 2028–2033.

Linking human perception and scientific coastal flood risk assessment (Anlo Beach Community, Ghana)

Policymakers concerned with coastal management issues have recently focused their efforts on how people perceive flood risk. Understanding the public's perception of risk has become an essential component of contemporary flood risk management, as it provides a basis for designing practical and effective flood mitigation strategies. This study was conducted in Anlo Beach, one of the most vulnerable coastal communities in Ghana. It investigated household perceptions of flood risk and examined them against independent physical measures that assess exposure. In parallel, multivariate regression analysis was conducted to identify and establish the key factors influencing household perceptions of flood risk in the study area. The results showed that two variables, previous flood experience (data collected through the social survey) and factual exposure (assessed through GIS measurements), played an important role in determining the level of flood risk reported by households. In particular, the relationship between previous flooding experience and perceived level of coastal flood risk was both positive and statistically significant. Socio-demographic factors did not have a significant influence on risk reporting. We conclude that perception variables collected through social surveys can be used as proxy indicators of environmental risks when physical measures are not available. Biases based on the socio-economic status of respondents may exist, but they do not outweigh information derived from people's factual relationships with the environment. Further studies on the above factors would support flood risk reduction measures in the study area and West Africa, particularly in light of climate change.

Modeling compound flood risk and risk reduction using a globally applicable framework: a pilot in the Sofala province of Mozambique

Abstract. In low-lying coastal areas floods occur from (combinations of) fluvial, pluvial, and coastal drivers. If these flood drivers are statistically dependent, their joint probability might be misrepresented if dependence is not accounted for. However, few studies have examined flood risk and risk reduction measures while accounting for so-called compound flooding. We present a globally applicable framework for compound flood risk assessments using combined hydrodynamic, impact, and statistical modeling and apply it to a case study in the Sofala province of Mozambique. The framework broadly consists of three steps. First, a large stochastic event set is derived from reanalysis data, taking into account co-occurrence of and dependence between all annual maximum flood drivers. Then, both flood hazard and impact are simulated for different combinations of drivers at non-flood and flood conditions. Finally, the impact of each stochastic event is interpolated from the simulated events to derive a complete flood risk profile. Our case study results show that from all drivers, coastal flooding causes the largest risk in the region despite a more widespread fluvial and pluvial flood hazard. Events with return periods longer than 25 years are more damaging when considering the observed statistical dependence compared to independence, e.g., 12 % for the 100-year return period. However, the total compound flood risk in terms of expected annual damage is only 0.55 % larger. This is explained by the fact that for frequent events, which contribute most to the risk, limited physical interaction between flood drivers is simulated. We also assess the effectiveness of three measures in terms of risk reduction. For our case, zoning based on the 2-year return period flood plain is as effective as levees with a 10-year return period protection level, while dry proofing up to 1 m does not reach the same effectiveness. As the framework is based on global datasets and is largely automated, it can easily be repeated for other regions for first-order assessments of compound flood risk. While the quality of the assessment will depend on the accuracy of the global models and data, it can readily include higher-quality (local) datasets where available to further improve the assessment.

Flood Hazard Mapping Using a Multi-Criteria Decision Analysis Approach Over the Indrawati River Basin

Floods are devastating natural hazard responsible for direct mortality, deterioration of crops, and damage to infrastructure and property. So, their study is crucial for watershed management and mitigation of flood hazards. The main objective of this study was to create a scientifically valid flood hazard map of the Indrawati River Basin (IRB) through the use of the multi-criteria decision analysis approach. Topographical Wetness Index (TWI), Elevation (EL), Slope (SL), Precipitation (PPT), Land Use/Land Cover (LULC), Normalized Difference Vegetation Index (NDVI), Distance from the River (DRI), Distance from the Road (DRO), Drainage Density (DD), and Soil Type (ST) were chosen as flood triggering factors based on literature review, data availability, and catchment characteristics. The analytic hierarchy process (AHP) method was used for determining the relative weight of each flood causative factor. All these factors were resampled into a 30 m × 30 m pixel size. Based on an evaluation of satellite imagery, 30 flood points were identified in the IRB, and these points were used as the testing dataset for validating the outcome. Based on results, the IRB has been classified into five different flood susceptible zones; very low, low, moderate, high, and very high. According to the study, 13%, 26%, 30%, 23%, and 8% of the total area are in very low, low, moderate, high, and very high flood susceptible zones, respectively. The Area Under the Curve (AUC) value for the success rate was 0.792. The results of this study will be crucial for concerned parties to design early warning systems and flood risk reduction measures for flood preparedness.

Protection Motivation Status and Factors Influencing Risk Reduction Measures among the Flood-Prone Households in Bangladesh.

Bangladesh, a low-lying deltaic country, experiences recurrent floods. To reduce the subsequent losses and damages, self-preparedness measures are imperative. In that context, the present study attempted to assess the flood protection motivation status of local flood-prone households through the evaluation of threat and coping capacities, as well as the identification of the factors that influence preparedness actions. Using Protection Motivation Theory (PMT), this study employed a mixed-method approach at three different flood-prone locations in Bangladesh: (1) Type 1 settlement, an area with ‘hard (flood embankment)’ flood risk reduction measures; (2) Type 2 settlement, without any risk reduction measure; (3) Type 3 settlement, with ‘soft’ measures put in place as part of NGO-led disaster risk reduction interventions. The study findings revealed a comparatively higher protection motivation status among the respondents living in the Type 3 settlement, in terms of evaluating the flood risk and capacity to take flood preparedness measures. The correlation analysis further illustrated that the factors of the perceived probability and severity of flooding, coping capacity, previous flood experience, reliance on NGO interventions, and gender status had an influence on the protection motivation of flood-prone households. Remarkably, no such influence was found for socio-economic factors such as education and income. It is hoped that the study findings can support the future decision-making process for designing preparedness interventions for communities in flood-prone areas.

Exploring urban growth–climate change–flood risk nexus in fast growing cities

This study looks at the nexus between urban growth, climate change, and flood risk in Doha, Qatar, a hot-spot, climate change region that has experienced unprecedented urban growth during the last four decades. To this end, this study overviews the main stages of Doha’s urban growth and influencing climatic factors during this period. A physically-based hydrological model was then built to simulate surface runoff and quantify flood risk. Finally, the Pearson correlation was used to verify the potential nexus between flood risk, climate change, and urban growth. Surveying showed that, between 1984 and 2020, urban areas grew by 777%, and bare lands decreased by 54.7%. In addition, Doha witnessed various climatic changes with a notable increase in air temperature (+ 8.7%), a decrease in surface wind speed (− 19.5%), and a decrease in potential evapotranspiration losses (− 33.5%). Growth in urban areas and the perturbation of climatic parameters caused runoff to increase by 422%, suggesting that urban growth contributed more than climatic parameters. Pearson correlation coefficient between flood risk and urban growth was strong (0.83) and significant at p < 0.05. Flood risk has a strong significant positive (negative) correlation with air temperature (wind speed) and a moderate positive (negative) correlation with precipitation (potential evapotranspiration). These results pave the way to integrate flood risk reduction measures in local urban development and climate change adaptation plans.

Assessment and appraisal of local governance on urban flood resilience in Bangkok Metropolitan Region: perspectives of SDGs 11 and 13

PurposeThe purpose of this study is to understand through the qualitative assessment, how the current strategy plans are geared toward reducing urban flood risks and achieving Sustainable Development Goals (SDGs) 11 and 13.Design/methodology/approachThe Bangkok Metropolitan Region (BMR) plays a major role in Thailand’s economic development. Thus, when the 2011 Thailand flood disaster occurred, BMR suffered major economic and social losses, which impacted the rest of the country. This mega disaster prompted policymakers, the academe and other relevant stakeholders to reevaluate and amend the current urban flood risk reduction measures and governance. The present study attempts to evaluate and compare the post-2011 Thailand flood disaster strategy and master plans, policies and reports that directly and indirectly reduce urban flood risks in the provinces of BMR. Basing on SDGs 11 and 13 targets that impact urban flood risk and resilience, a set of criteria was developed to screen, score and asses the selected documents. A screening process of three levels are conducted to limit the documents to be reviewed, and subsequent content analysis for scoring also has been done.FindingsThe projected results indicate the need for improved and increased number of localized strategic plans and policies, which are more comprehensive and integrated as risk governance documents.Research limitations/implicationsFurthermore, it is projected that there is need to integrate measures to increase adaptive capacity for BMR.Originality/valueThis study is original, and methodology can be replicated for other urban areas for flood risks and resilience assessment.

Contested flood risk reduction: An analysis of environmental and social claims in the city of Genoa

The most recent significant episodes of floods in terms of victims and damages in the city of Genoa occurred in 2011 and 2014. After 2014, the Italian government has changed its approach to flood risk management (FRM), adopting what has been called a change of direction towards flood risk reduction (FRR). Accordingly, the city has been involved in a process of governance and urban restructuring. In the wake of these governance and infrastructural transformations, I have conducted thirty-five semistructured interviews with local stakeholders. I use the results to discuss the adopted measures and their acceptability for the local community, focusing in particular on identifying the reasons and different narrative frames that move social dissent. The main reasons for dissent have been identified following two situations: no-recognition of the effectiveness of some works, and lack of adequate measures. Conclusions are that such manifestations of dissent could generate a discussion about the validity by the adopted FRR measures and claim for a more participative approach to the analysis of benefits and impacts produced by such measures. What emerges is in line with last international calls to overcome a technocratic approach to post-disaster, giving more space to community's needs.

A study on the making of flood risk reduction measures of cities damaged by flood

A study on the making of flood risk reduction measures of cities damaged by flood

Framework for climate proofing of flood risk management strategies in Finland

Climate change impacts have not previously been systematically considered in the selection and prioritisation of measures to manage flood risks in Finland. For the second flood risk management planning cycle according to the EU Floods Directive, we developed a framework for evaluating the adaptability of measures to expected changes in climate and land use. Our aim was to (1) provide regional data for flood risk managers and water resources planners, (2) develop a nationally consistent approach to identify the robustness of considered measures for a variety of conditions which (3) is applicable in both river basin management planning and flood risk management planning. According to the feedback from practitioners in regional flood management groups as well as planners, the framework helped to raise new thoughts and to open new perspectives in the planning process and may hence influence the practice of planning of flood risk reduction measures. Also, it was found useful to have access to regional, tailored data on hydrological impacts in the planning process and during communication with stakeholders. The described methodology has been used in the preparation of the 2nd version of flood risk management plans and for the 3rd version of river basin management plans. It is intended to use the same approach for next planning cycles.

Cartografía de inundaciones en la planificación territorial. Estudio comparado entre Argentina y España

Flood risk management has gained new prominence thanks to the incorporation of cartographic tools in spatial planning. Flood risk mapping has been incorporated in several countries as an important piece when it comes to planning new land uses. Thus, traditional flood risk reduction measures based on structural measures have been enriched with the incorporation of risk mapping as an argument for legal accreditation in land use planning. This paper analyzes the application of flood risk mapping in land use planning in Argentina and Spain. The analysis is focused on the use of cartographic documents to certify risk levels at a local scale. These are two countries that have opted for the elaboration of risk mapping in the processes of assigning land uses. Although the results of their implementation are different in relation to the existence of regulatory regulations for these processes and the different administrative scales with competences in spatial planning and urban planning. In both cases, it is verified that the flood map in urban processes is understood as a hazard map, without integrating, except for specific examples, vulnerability analysis in the territories under planning.

Multiscale Hydrogeomorphometric Analysis for Fluvial Risk Management. Application in the Carrión River, Spain

The sustainable management of fluvial systems requires reliable knowledge of the mechanisms that control the basins and their drainages, which in turn must be prioritized for the application of measures for flood-risk reduction. Thus, given the need to develop methodological frameworks capable of integrating remote sensing technologies at different scales, as well as traditional metrics and anthropic variables, in this study, a multiscale method is proposed for the characterization and prioritization of river stretches for fluvial risk management. This methodology involves the study of drivers at the watershed level, and a detailed morphometric and hydrogeomorphological analysis of the main channel for fluvial landscape classification, segmentation, and aggregation into units, considering also anthropic variables. Therefore, it includes the use of LiDAR data and exploration GIS tools, whose results are corroborated through fieldwork, where ephemeral and topographic evidence of fluvial dynamics are collected. The procedure is validated in the Carrión river basin, Palencia, Spain, where a high degree of maturity and geomorphological development are determined. Hence, the main channel can be classified into eight geomorphic units and divided into homogeneous segments, which, according to categorical elements such as urban interventions, are prioritized, obtaining, as a result, six stretches of main interest for river risk management.

Make it personal: Introducing intangible outcomes and psychological sources to flood vulnerability and policy

Vulnerability assessments play a central role in deciding on measures for flood risk reduction. Vulnerability itself manifests as tangible (e.g. building damage) and intangible (e.g. distress, disruption of livelihoods) outcomes caused by a flood event. Traditionally, vulnerability assessments have been focusing on the physical and social sources that drive these outcomes, while psychological sources have largely been neglected. This paper expands the current physical and social perspective on vulnerability by demonstrating the added value of psychological sources to more accurately identify those who are most vulnerable to flooding. Based on survey data of 1127 households living in flood-prone areas in Austria, we confirm that tangible and intangible outcomes represent conceptually distinct types of flood impacts. A series of hierarchical regression models shows that psychological sources do not play a critical role for tangible outcomes, as they do not significantly add to the variance already explained by physical and social indicators. However, psychological sources have substantial unique explanatory value for intangible outcomes, and may supersede certain physical indicators (e.g., risk zone is a physical proxy indicator for the underlying psychological factor ‘perceived flood probability’). By contrast, social indicators retain their effect size even if psychological indicators are included. Thus, expanding the scope of vulnerability outcomes calls for simultaneously expanding the scope of sources of vulnerability. The results caution against catch-all risk reducing measures; instead, risk managers should address the vulnerability sources specific to particular outcomes. To improve social equity, flood policy instruments should incorporate intangible outcomes and psychological sources of vulnerability.

Proposal of a method for assessing combined flood risk reduction effect by hazard control measures and exposure reduction measures based on limited data

AbstractThis article verifies the applicability of an assessment method on flood risk reduction, combining and assessing hazard control measures and exposure reduction measures together. The method develops collated flood risk curves and uses limited data, so it is an approach which can be readily applied in developing countries, where an understanding of flood risk reduction measures are become increasingly important. The method was proposed as a result of studies conducted by the National Institute for Land and Infrastructure Management, Ministry of Land, Infrastructure, Transport and Tourism, Japan. When applying the method to a river improvement and relocation scheme with land mounding in Mindanao, the Philippines, the advantages and limitations of the method are considered.