Integrated Flood Risk Management Research Articles

A systematic framework for assessing social vulnerability to flood for integrated flood risk management: A case study in Metro Manila, Philippines

Assessing social vulnerability to floods (SVF) is a crucial component of integrated flood risk management, especially in flood-prone regions such as Metro Manila in the Philippines. This study presents a holistic framework to assess SVF, based on susceptibility, exposure, and resilience factors while recognizing its multi-dimensional, multi-attribute, and context-dependent nature. The assessment was applied to three cities of Metro Manila: Marikina, Parañaque, and Manila. Indicators were systematically identified using deductive and hierarchical approaches, and factor indices were derived using a combined Simple Additive Weighting and Analytic Hierarchy Process, while the SVF index was estimated using the vulnerability relationship of the factors. The results exhibit a strong positive correlation with historical social flood damages and robustness across weight and normalization variations, with Marikina being the most vulnerable, followed by Parañaque and Manila. The city-level vulnerability profiles highlight salient determinants such as high population exposure in Parañaque, a relatively high population of susceptible social groups in Marikina, and significant disparity in flood control projects among the cities. Scenario analyses underscore the efficacy of flood countermeasures that reduce exposure and increase resilience. This study offers valuable insights and practical guidance for developing effective disaster reduction plans and policies in the study areas and similar regions by identifying disparities in vulnerability and understanding local conditions and drivers.

Unveiling the assessment process behind an integrated flood risk management plan

In the context of the European Floods Directive, flood risk assessment is a critical component for the definition of an integrated management plan that operates within a multidimensional landscape shaped by intricate interactions. This study explores this complex interplay using a comprehensive framework, aimed at enlightening the non-linear pathways that flood risk assessments can traverse. It adopts the Gioia Methodology within the Grounded Theory approaches, enabling a nuanced exploration of flood risk assessment dynamics. Utilizing data from an Italian case study in the Po River District, this study unveils the flood risk assessment process framework by identifying 13 first-order codes, 6 s-order themes and 3 aggregate dimensions. It introduces a qualitative self-assessment tool to facilitate integration across dimensions and enhance Directive alignment, offering valuable insights for future flood risk assessment implementations.

Current flood risk management: gaps and perspectives in Stung Sen Catchment, Cambodia

ABSTRACT People who live in Cambodia's flood-prone areas are at a heightened risk of experiencing a flood disaster due to climate change and urbanization. Annual flood disasters have an impact on the Stung Sen River Basin, the largest tributary river of Tonle Sap Lake. Through interviews with pertinent stakeholders, we investigate the current gaps in flood control risk management at the Stung Sen Catchment, the national to local levels. At a common level, the Kampong Kor, Kampong Svay, and Meanchey were selected for the interview and field survey. The findings highlight that a top-down approach is used to alert locals about potential flood danger. The results emphasized the difficulties in addressing cross-border flood warning issues, the effects of incorrect urbanization development and climate change on vulnerable populations, and the inadequate readiness for the safety of children in flood-prone locations. Consequently, we suggest the integrated flood risk management framework as a very effective way to lessen the impact of flood risk for both present and future flood risk harm.

Stakeholders’ Forum on Integrated Flood Risk Management in Cagayan River Basin: Basis in Writing Policy Recommendations

Stakeholders’ Forum on Integrated Flood Risk Management in Cagayan River Basin: Basis in Writing Policy Recommendations

Two Decades of Integrated Flood Management: Status, Barriers, and Strategies

Losses from flood disasters are increasing globally due to climate-driven forces and human factors such as migration and land use changes. The risks of such floods involve multiple factors and stakeholders, and frameworks for integrated approaches have attracted a global community of experts. The paper reviews the knowledge base for integrated flood risk management frameworks, including more than twenty bibliometric reviews of their elements. The knowledge base illustrates how integrated strategies for the reduction of flood risk are required at different scales and involve responses ranging from climate and weather studies to the construction of infrastructure, as well as collective action for community resilience. The Integrated Flood Management framework of the Associated Programme on Flood Management of the World Meteorological Organization was developed more than twenty years ago and is explained in some detail, including how it fits within the Integrated Water Resources Management concept that is managed by the Global Water Partnership. The paper reviews the alignment of the two approaches and how they can be used in tandem to reduce flood losses. Success of both integrated management approaches depends on governance and institutional capacity as well as technological advances. The knowledge base for flood risk management indicates how technologies are advancing, while more attention must be paid to social and environmental concerns, as well as government measures to increase participation, awareness, and preparedness. Ultimately, integrated flood management will involve solutions tailored for individual situations, and implementation may be slow, such that perseverance and political commitment will be needed.

Flooding in the urban fringes: Analysis of flood inundation and hazard levels within the informal settlement of Kibera in Nairobi, Kenya

Overlapping conditions of rapid urbanisation and climate change across developing countries are threatening the capacity of cities to manage climate risks, especially in the flood-exposed low-income peripheral areas. Limited studies have applied hydrodynamic flood models in ascertaining flooding conditions, supportive of risk-informed decisions in such urban fringes. Against this backdrop, we assessed plausible flooding and hazard conditions in the low-lying villages of Lindi and Silanga in Kibera informal settlement. The coupled one-dimensional and two-dimensional hydrodynamic model, customised from the Hydrological Engineering Centre's River Analysis System (HEC-RAS) was parameterised for flood simulation under different hydrological regimes and scenarios associated with flooding in Kibera. Volumetric flow estimates and a computed energy slope were used to define the upstream and downstream modelling boundary conditions respectively. Trial-and-error adjustment of the flow resistance coefficients from land-use features was applied in model calibration, and the results compared to the surveyed flood of 23rd April 2019. Results show that proximal areas to the Ngong River and Nairobi dam face high flood risks. A flood volume of 11.7×105m3 from a 2.5h, 50 mm rainfall could potentially inundate about 2.0% and 8.3% of areas in Lindi and Silanga respectively, while a volume of 48.9×105m3 from a 100-year storm of 172 mm could inundate about 10.6% of Lindi and 29.1% of Silanga. Upstream steeply sloping topographies of the villages increase flood velocities and risk of drowning, while the lower reaches at relatively flatter topographies, experience attenuated flow and rapid accumulation of flood waters, hence, higher flood depths. These results can support policy interventions for integrated flood risk management in Kibera, as a way of mainstreaming the underserved urban communities in climate risk management.

Following up on flood adaptation in Québec households four years later: A prospective exploratory study

The frequency and severity of flooding events are expected to increase with climate change in Canada's province of Québec. Highly publicized flooding events ravaged the province's waterfront communities in 2017 and 2019, with dire health and economic impacts. A recognized component of integrated flood risk management is the adoption of adaptive behaviors that reduce the vulnerability of exposed households to flooding. A previous study established an index of pre-flood adaptation based on 15 behaviors, using responses of 1951 participants residing within or less than 150 m from officially designated high flood risk zones. 325 of these respondents were successfully recontacted in 2019 for a follow-up survey on their adaptive behaviors, constituting the longitudinal sample used in this study. The new database tracks changes in pre-flood adaptation of Quebecers over a span of 4 years and seeks to establish experiential, socio-demographic, and psychosocial variables that predict the preventive behavior adoption rates four years on. Results suggest that there has been no significant increase in the level of adaptive behavior between 2015 and 2019, though households that have experienced a flood or a flood alert in the past are more likely to adapt than those who have not. Furthermore, the most important measures reported in 2015 for predicting adoption of behaviors four years on are income, the experience of a flood, and the belief that one lives in a flood-prone zone. Finally, a second stepwise regression indicates that a change in flood experience, an increase in perception of the severity of flood impacts on one's residence, and adaptation in 2015 are the strongest predictors of adaptation in 2019. Results from this exploratory longitudinal study provide critical information regarding flood adaptive behavior over a long period of time, and its predictors.

Explaining Changes in Threat Appraisal, Coping Appraisal, and Flood Risk-Reducing Behavior Using Panel Data From a Nation-Wide Survey in Germany

Protection Motivation Theory (PMT) has become a widely-used theoretical framework to explain the risk-reducing behavior of individuals toward flooding and other natural hazards. Despite a quickly growing body of literature applying PMT in the context of flooding, insights into changes in PMT components and risk-reducing behavior are largely lacking due to a predominant use of cross-sectional research designs. In this study, we examine how various intrapersonal sources of information relate to changes in PMT components and risk-reducing behavior, using unique panel data ( n = 2,680) from a survey in Germany and a fixed-effects regression modeling approach. In line with PMT, we find that various intrapersonal sources of information, like prior experience, relate to changes in PMT components. We also find that coping appraisals of PMT change in a direction negatively related to risk-reducing behavior over time, posing a challenge for risk communication and the envisaged shift to integrated flood risk management.

Conflicting and complementary policy goals as sectoral integration challenge: an analysis of sectoral interplay in flood risk management

The paradigmatic shift from traditional flood defense toward integrated flood risk management has widened the sectors and policies affected and has spurred a growing interest of scholars to understand cross-sectoral flood policy integration. In this paper we argue that the cross-sectoral goal relationship—ranging from complementary to conflictual policy goals—is a useful conceptual framework to understand (1) the policy integration challenge at hands and (2) in particular the unfolding policy integration from a processual perspective. For our empirical analysis we identify three policy subsystems that are highly important for sectoral interplay in flood risk management: agriculture, hydropower generation, and spatial planning. Using Austria as a case study we illustrate the goal relationships and sectoral policy integration challenges in each of these fields of interaction. Based on 45 expert interviews in the selected policy sectors we provide useful insights into the current processes of flood policy integration. The empirical findings from our case studies show that sectoral goal relationships and the nature of the policy integration challenge drive flood policy integration. More pronounced land use conflicts are more strongly reflected in different actor interests, policy frames, policy goals, and the choice of policy instruments. Sectoral goal relationships are an important factor to explain the unfolding policy integration process. Complementary policy goals result in rather informal, harmonious integrative negotiations on strengthening synergies by using soft policy instruments. On the contrary, conflictual policy goals lead to more formal negotiations among the affected sectors relying on hard, regulative instruments.

An Expanded Interpretive Structural Modeling Analysis of the Barriers to Integrated Flood Risk Management Adaptation in Metro Manila

The implementation of integrated flood risk management (IFRM) is still in its infancy in both developed and developing countries, yet some countries have already encountered barriers to IFRM adaptation. The interrelationships between these barriers need to be determined and analyzed systematically, as such an analysis is the groundwork for decision-making when devising solutions to overcome the barriers. Interpretive Structural Modeling (ISM) is a popular and systematic method for analyzing the interrelationship between variables in broad study areas. This study applies the proposed expanded ISM (Ex-ISM) approach to comprehensively analyze the interrelationships between the barriers to IFRM in Metro Manila. Ex-ISM enhances conventional ISM in that the symbolism is modified to explicitly show the contextual interrelationships, the step for hierarchy assignment is simplified, and the diagram shows all of the interrelationships that allow a comprehensive analysis. The results obtained using the Ex-ISM method do not deviate from those yielded by the conventional ISM method, but the Ex-ISM method allows an easy assignment of hierarchy, and it shows not only the direct but also the indirect interrelationships to provide a comprehensive analysis of the relationships between the barriers.

Contributed Indicators to Fluvial Flood Along River Basin in Urban Area of Indonesia

Flooding is the most common disaster in Indonesia, it is classified as a disaster if it affects humans causing physical and financial losses. Flood damage depends on the type of flood, flow velocity, and duration. The increase in population will cause an increase in infrastructure that will affect the environment, including the carrying capacity of rivers and catchment areas, while flooding in urban areas will also have an impact on infrastructure and assets, increasing flood damage. This study discusses the factors that cause flooding (rainfall, topography, soil type, land slope, distance from rivers, river waste, population density, etc.), as well as various types of floods that occur. The method used in this research was based on the qualitative analysis of the information from the government and literature over the last five years obtained from online databases and search engines. The results of this study can provide a reference for the theory regarding disaster risk assessment and flood hazard prediction in watersheds. This research was conducted in the Ciliwung Watershed (DAS), where the factors and the dominant type of flooding were determined. Knowing the contributing factors can be beneficial for flood risk management. This research focuses on identifying factors that contribute to fluvial flood events and understanding their influence so that a more integrated flood risk management that takes into account the upstream, middle, and downstream parts of the watershed can be arranged in other areas based on the example of measures implemented by the local government in the Ciliwung watershed. This conceptual effort provides a much-needed foundation for developing better mitigation efforts in watersheds.

Integrated Flood Risk Management Approach Using Mesh Grid Stability and Hydrodynamic Model

Today, inhabitants residing in floodplains face a serious and perpetual threat of flooding. Flooding causes fatalities and considerable property damage in metropolitan areas. Therefore, robust structural measures need to be adopted to eliminate flood catastrophe. Structural measures in the floodplain are the most promising solutions. However, there are cost-associated factors for proposing a flood retention plan. Navsari city (98.36 km2, area extent) of Gujarat was used as a case study to investigate the impact of mesh grid structures (100 m, 90 m, and 50 m) along with structural measures for the preparation of a flood retention plan. The HEC-RAS 2D hydrodynamic model was performed for the Purna River. The output of the model was characterized by four different scenarios: (i) Without weir and levees (WOWL), (ii) With weir (WW), (iii) With levees (WL), and (iv) With weir and levees (WWL). The statistical parameters (R2, RMSE, NSE, inundation time, and inundation area) were determined to evaluate model accuracy. The outcome of the model revealed that a 50 m size mesh grid exhibited more accurate results, yielding high NSE and R2 values (0.982 and 0.9855), a low RMSE value (0.450 m), and a smaller inundation area (114.61 km2). The results further revealed that the WW scenario was the most effective flood retention measure as it delayed the flood water for up to 16 h, and managed the flood with the WOWL case. Moreover, the mean error (WW scenario) estimated from profiles 1 and 2 ranged from (−0.7 to 0.62) and from (−0.1 to 0.02 m), respectively, which were evaluated as very low when compared with other scenarios. The novel scenario-based flood retention plan emphasizing the stability of mesh grid structures using the hydrodynamic model can be applied to any other region around the globe to recommend efficacious structural flood measures for flood decision making systems.

Assessing Future Flood Risk and Developing Integrated Flood Risk Management Strategies: A Case Study from the UK Climate Change Risk Assessment

As Earth’s climate changes, individual nations must develop adaptation plans to respond to increasing or new climate risks. This study focuses on changing flood risk in England, UK, and examines the policy framework and actions that underpin England’s adaptation from a flood risk management (FRM) perspective. Specifically, the flood risk projections that fed into the UK’s Climate Change Risk Assessment were analysed alongside newly developed FRM adaptation portfolios that modified the flood risk projections to identify the potential of different measures to reduce Expected Annual Damages (EAD). The key findings indicate that: the range of EAD for all flood sources combined is projected to increase by 18–160% by the 2080s depending on the climate change, population growth and adaptation assumptions applied; adopting an enhanced adaptation approach presents an opportunity to manage much of the climate driven change in flood risk, particularly from river flooding; EAD from coastal flood risk shows the greatest increase relative to present day; and surface water flooding will become an increasingly more significant source of flood risk. Interpretation of the results in the context of the policy framework shows how greater coordination and integration of risk managers and interventions is required to improve adaptation planning.

Holistic characterization of flash flood vulnerability: Construction and validation of an integrated multidimensional vulnerability index

• Integrated and multidimensional approaches are key to identifying vulnerability underlying causes. • Validation of vulnerability indices can be tackled through sensitivity and uncertainty analysis. • Integrated and multidimensional vulnerability analysis is key to tackling integrated flood risk management. Over the last twenty years, numerous strategies and policies (e.g., 2030 Agenda for Sustainable Development) have emerged to promote flood risk reduction that is compatible with the conservation or restoration of river ecosystems, with the ultimate goal of achieving sustainable development. In this context, vulnerability analysis is considered a key aspect in flood risk reduction, and the most widespread methodology for its characterization is the construction of indices. However, such indices have been obtained so far through a fragmented approach, either because they do not consider all vulnerability dimensions (i.e., social, economic, ecosystem, physical, institutional and cultural) or components (i.e., exposure, sensitivity and resilience). Moreover, indices developed on a regional scale focusing on areas prone to flash floods are rarely validated, as the necessary information is often not available and flash floods do not occur simultaneously in all urban areas of a given region. This paper addresses the above two knowledge gaps and describes the construction at regional level of a flash flood Integrated Multidimensional Vulnerability Index (IMVI). Vulnerability here is characterized holistically, integrating in the index all the dimensions and components involved. Subsequently, an uncertainty and sensitivity analysis was performed to validate the IMVI. Lastly, vulnerability regional spatial patterns were identified through a Latent Class Cluster Analysis. The methodology implemented here allows one to identify vulnerability sources and their underlying causes, helping to improve flood risk management. Moreover, validation outputs enable to determine index uncertainty sources, thereby encouraging decision-makers to design more cost-effective vulnerability reduction strategies.

The determinants affecting the intention of urban residents to prepare for flood risk in China

Abstract. In the context of global warming and China's disaster response patterns, it is critical to understand how to promote the effectiveness of household flood protection measures among the public. In this study, we developed a comprehensive theoretical framework based on protection motivation theory (PMT) to identify the main determinants that influence urban residents' intention to prepare for flood risk. In addition to the fundamental factors in PMT, this framework also considered the influence of individual coping attitudes and social context. We selected urban residents in flood-prone areas of Henan Province as the study population as well as collected 857 valid questionnaires through an online survey. Firstly, the results showed that both threat perception and coping appraisal of flood risk are effective in increasing residents' intention to prepare. Secondly, negative risk-coping attitudes reduced people's intention to prepare. If people do not perceive preparedness actions as absolutely necessary, they will postpone them or shift their focus to public flood protection measures. In addition, analysis of affective pathways revealed that negative emotion (worry) was primarily influenced by perceptions of flood consequences and was not significantly related to perceptions of likelihood. The analysis of trust mechanisms showed that higher levels of trust in public flood protection reduced people's perceptions of flood risk, thereby hindering their intention to prepare for flood risk. Finally, we found that the positive influence of social norms on preparedness intentions makes it appropriate to focus on the power of social mobilization. The findings will provide theoretical references for government departments to design further policy measures to improve integrated flood risk management in China.

Satellite-Based Flood Inundation and Damage Assessment

Because recurring floods in the Philippines have become more damaging throughout time, risk assessments, quantifying, and visualizing flood damages as accurately as possible become imperative. To deal with an up-todate database and a practical assessment tool, a satellite imagery-based method was used which aimed to map flood inundation and estimate damages brought by the flood during Typhoon Ulysses. This paper presents a framework for an integrated flood risk management in a river basin context with the following components as follows: 1) collection of the comprehensive database containing information relevant for flood analysis; 2) use of a satellite-imagery based method for flood inundation map using Google Earth engine; 3) validation of map accuracy through quick post-flood participatory approach. Analysis of the recent flood inundation event in November 2020 in Cagayan Valley, Philippines showed the inundation of an extensive area of 620.88 km2 affecting the Cagayan province at 55.91% and Isabela province at 44% share of inundation. The flood severely affected approximately 614.05 km2 of the total croplands. Using a participatory validation approach, the overall accuracy of datasets used is 97.78% while flood extent is 95%. Through this study, the framework, approach, and methodology can be replicated in other locations in the Philippines and in other countries which recurrently experience flooding.

Designing policy instruments for regional floodplain management in Austria: the role of effectiveness and legitimacy

ABSTRACT This article explores the issue of regional floodplain management in Austria from a policy design perspective. Austria has experienced a series of major floods in recent years. In response to these flood events a range of policy instruments at the land–water nexus were developed. Three policy instruments were selected as case studies to represent this policy shift toward integrated flood risk management: (a) regulatory spatial planning, (b) water associations and (c) financial compensation schemes for flood storage. The main objective of our article is to build a better understanding of the interlinkage of effectiveness and legitimacy in the process of policy formulation. The analysis draws on a review of policy documents and expert interviews with core decision-makers. Our analysis shows that the main challenge in the selection process is not the issue of effectiveness, but rather the acceptance of the policy instrument by target groups. Stakeholder participation increases the legitimacy of the instrument design and minimizes conflicts in the following implementation, thereby increasing the effectiveness of the policy instrument. In contrast to the assumptions prevailing in the current policy design literature, our empirical analysis does not support the common preposition that participatory processes result in inferior forms of policy design.

The presence of moral hazard regarding flood insurance and German private businesses

There is a movement towards the concepts of integrated flood risk management and governance. In these concepts, each stakeholder prone to flooding is tasked with actively limiting flood impacts. Currently, relatively more research has focused upon the adaptation of private households and not on private businesses operating in flood-prone areas. This paper offers an extension of this literature on business-level flood adaptation by exploring the potential presence of moral hazard. The analyses are based on survey data collected in the aftermath of six floods across Germany between 2002 and 2013 to provide a first indication of the presence of moral hazard in private businesses. Moral hazard is where increased insurance coverage results in policyholders preparing less, increasing the risk they face, a counterproductive outcome. We present an initial study of moral hazard occurring through three channels: the performance of emergency measures during a flood, changes in precautionary behavior employed before a given flood occurred, and changes in the intention to employ additional precautionary measures after a flood. We find, much like for private households, no strong indication that moral hazard is present regarding past adaptation. However, there is a potential avenue after 2005 for insurance coverage to lower businesses’ intentions to employ more adaptation measures after a flood. This has significant policy relevance such as opportunities for strengthening the link between insurance and risk reduction measures and boosting insurance coverage against flooding in general.

A review on analysis of flood modelling using different numerical models

The incidence of flooding events and the threat they pose in urban areas is a growing global issue, but it is particularly acute in developing countries like India, where the hazard is typically underrecognized and understudied. With current estimates indicating that future scenarios would become more severe, it is necessary to adopt integrated flood risk management solutions that involve flood modelling. This study is part of a bigger effort to quantify and simulate urban flood dangers. It emphasizes cutting-edge research and concepts in the area of urban flood risk management. It reviews the literature on current flood modelling approaches and provides a comprehensive overview of the different approaches, including their advantages and disadvantages. Indeed, flood modelling research has been extensive throughout the years, leading in the development of a diverse array of models, databases, and methodologies for simulating flood hydrodynamics. However, the actual potential of these developments in terms of flood risk management has yet to be shown. There is currently no perfect model or generic approach that can adequately capture all aspects of flood hydrodynamics over a broad variety of study locations. As a consequence, extensive calibration of state-of-the-art flood models is crucial for resolving current challenges in flood modelling. Additionally, the prospect of developing unique flood models based on fundamental mathematical formulations that are simple to parameterize by using global, open source, and publicly accessible data should pique academics' attention.

Stakeholder analysis: Mapping the river networks for integrated flood risk management

In recent decades, a change of paradigm in flood risk management (FRM) has been taking place worldwide. The most current legislation and policies reflect this. This change of paradigm implies a gradual transition towards the adoption of more proactive, integrating strategies which require investment in nature-based solutions (NbS) to mitigate flood risk while ensuring the good status of water bodies and restoring river-floodplain systems. To be effective, this transition should be accompanied by an evolution in governance: from top-down approaches to bottom-up schemes in which empowered and well-endowed stakeholder engagement becomes essential. However, the still limited experiences in implementing this combination present numerous potential difficulties and barriers. We use empirical techniques of social network analysis in combination with latent class cluster analysis to diagnose ex-ante these potential challenges to guide policy makers in designing suitable strategies of communication and involvement of stakeholders in the decision-making process. The analysis is carried out in two stages: (i) identifying and examining the relationships of key stakeholders involved in the management, conservation and exploitation of fluvial systems; and (ii) categorising stakeholders according to their perception of the effectiveness of NbS. Only by creating a cohesive and power-balanced river network is it possible to implement just and legitimate FRM strategy.