Flood Mitigation Projects Research Articles

Triple exposure: the geographic correlation between flood risk, climate skepticism, and social vulnerability in the United States

Abstract This study investigates the geographic correlation between flood risk, climate skepticism, and social vulnerability across the United States. Our results reveal a systematic underestimation of flood risk in the Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Maps, especially in Appalachia, parts of New England, and the Northwest. These three regions face two additional risks: high levels of social vulnerability and skepticism about climate change. Nationally, there is a statisically significant correlation (0.19, p < 0.005) between flood risk and climate change skepticism, which increases (0.28, p < 0.005) in regions with high FEMA undercounts and elevated flood risk. Climate change skepticism manifests as distrust in science, an underestimation of property and community risk, and a resistance to mitigation and adaptation efforts. Indicators of social vulnerability, such as poverty rates, physical disabilities, unemployment, households in mobile homes, and lack of vehicle access, are especially pronounced in Appalachia. Addressing this geographically-embedded triple exposure—flood risk, social vulnerability, climate change skepticism— requires strategies to enhance local resilience. These include revising the 100-year floodplain categorization in FEMA’s National Flood Insurance Program to better reflect climate change, conducting public education campaigns in vulnerable communities, and scaling-up financial assistance for flood mitigation and adaptation projects.

Potential of Tambo Dam implementation as a flood control measure

AbstractRecent climate change has resulted in severe and frequent natural disasters globally, prompting the need for adaptation to these events. As an adaptation measure, disaster prevention and mitigation using natural processes and mechanisms (or ‘green infrastructure’) have become widely recognized in many countries. Ecosystem‐based disaster risk reduction has been promoted in Japan since 2015. The ‘Tambo Dam’, a flood mitigation project using paddy fields in which the authors have participated, has the potential to become one of the most extensive forms of green infrastructure in Japan. This study outlines the runoff control mechanisms of Tambo Dams, demonstrates their effectiveness in reducing flood damage at the watershed scale, and discusses two key factors for successful sustainable efforts: the design of appropriate runoff control equipment and administrative schemes that support incentives for the efforts of farmers. The results indicated that Tambo Dam implementation represented a crucial strategy for managing agricultural resources. The functionality of paddy fields could be preserved by managing them as Tambo Dams. This approach not only contributes to flood control but also ensures a swift return to rice cultivation during emergencies. Moreover, establishing a system akin to the Tambo Dam initiative of Mitsuke City, supported by the ‘Direct Payment Scheme for Multifunctional Activities’ for maintenance and management, could ensure the feasibility of Tambo Dam implementation.

Changed Seasonality and Forcings of Peak Annual Flows in Ephemeral Channels at Flagstaff, Northern Arizona, USA

Flood variability associated with urbanization, ecological change, and climatic change is of increasing economic and social concern in and around Flagstaff, Arizona, where flood hydrology is influenced by a biannual precipitation regime and the relatively unique geologic setting at the edge of the San Francisco Volcanic Field on the southern edge of the Colorado Plateau. There has been limited long-term gauging of the ephemeral channels draining the developed lands and dry coniferous forests of the region, resulting in a spaciotemporal gap in observation-based assessments of large-scale flooding patterns. We present new data from over 10 years of flood monitoring using a crest stage gauge network, combined with other channel monitoring records from multiple agency sources, to assess inter-decadal patterns of flood change in the area, with a specific emphasis on examining how various controls and disturbances have altered the character and seasonality of peak annual flows. Methods of analysis included the following: using Fisher’s Exact Test to compare the seasonality of flooding between historic data spanning the 1970s and contemporary data obtained since 2010; summarizing GIS-based spatial data and meteorological timeseries to characterize study catchment conditions and changes between flood study periods; and relating spatiotemporal patterns of flood seasonality and occurrences of notably large floods with catchment characteristics and environmental changes. Our results show systematic patterns and changes in Flagstaff-area flood regimes that relate to geologic and topographic controls of the varied catchment systems, and in response to records of climate variations and local catchment disturbances, including urbanization and, especially, high-severity wildfire. For most catchments there has been a shift from predominantly late winter to spring snowmelt floods, or mixed seasonal flood regimes, towards monsoon-dominated flooding, patterns which may relate to observed local warming and precipitation changes. Post-wildfire flooding has produced extreme flood discharges which have likely exceeded historical estimates of flood magnitude over decade-long monitoring periods by one to two orders of magnitude. We advocate for continued monitoring and the expansion of local stream gauge networks to enable seasonal, magnitude-frequency trend analyses, improved climate and environmental change attribution, and to better inform the many planned and ongoing flood mitigation projects being undertaken in the increasingly developed Flagstaff region.

Geo-spatial analysis of built-environment exposure to flooding: Iowa case study

Flooding is the most frequent type of natural disaster, inducing devastating damage at large and small spatial scales. Flood exposure analysis is a critical part of flood risk assessment. While most studies analyze the exposure elements separately, it is crucial to perform a multi-parameter exposure analysis and consider different types of flood zones to gain a comprehensive understanding of the impact and make informed mitigation decisions. This research analyzes the population, properties, and road networks potentially exposed to the 100, 200, and 500-year flood events at the county level in the State of Iowa using geospatial analytics. We also propose a flood exposure index at the county level using fuzzy overlay analysis to help find the most impacted county. During flooding, results indicate that the county-level percentage of displaced population, impacted properties, and road length can reach up to 46%, 41%, and 40%, respectively. We found that the most exposed buildings and roads are laid in residential areas. Also, 25% of the counties are designated as very high-exposure areas. This study can help many stakeholders identify vulnerable areas and ensure equitable distribution of investments and resources toward flood mitigation projects.

Re-visit project success: evaluation of visitor perspectives in the Sungai Melaka flood mitigation project

Purpose This interdisciplinary study re-evaluates the Sungai Melaka flood mitigation project’s impact on community success in Malaysia’s UNESCO World Heritage site, broadening the definition of success considering historical and cultural significance. This study aims to revisit success metrics, focusing on the project’s influence on people’s interactions, cultural well-being, social cohesion and heritage preservation. Design/methodology/approach This study explored visitors’ reviews of their experience visiting Sungai Melaka in several data collection stages. The first data collection involved a Web survey posted on Facebook to capture diverse perspectives of the population and grasp the core strand of knowledge to focus on the second data collection, the questionnaire. The final stage involved interviews to generate rich qualitative data. Findings The findings of this study revealed that the impact exceeded tangible outcomes, as the project impacted people’s interactions and practices. This research assesses cultural benefits, incorporating these indicators into evaluating cultural ecosystem services by capturing local visitors’ and communities’ perceptions, preferences and behaviours. The findings found that other project success attributes include identities, capabilities and experience, further defining learning, health, economics, connection to nature and symbolism. Originality/value This research explores the meaning of project success beyond the traditional metrics by capturing success from the users’ perspectives and people’s interaction and their impact on culture and well-being. The cultural ecosystem services framework used in this study is applied to explore the interactions between people and the facility and its effect on the people.

Enhancing flood risk assessment in the Johor River Basin through trivariate copula

ABSTRACT Copulas are a vital statistical tool, particularly in hydrology, for understanding complex relationships among flood characteristics. This study focuses on three key flood features: peak discharge, flood volume, and flood duration, using trivariate copulas to capture their interdependencies. This is crucial because bivariate and univariate analyses fall short in considering all three factors simultaneously. To handle extreme flood values, L-moment is proposed over maximum likelihood estimation and inference function margin due to its enhanced reliability and susceptibility to outliers and extreme values. Akaike information criterion was employed to identify the best-fit marginal distribution and copula. The Lognormal distribution effectively models peak discharge, while Weibull and generalized extreme value distributions fit flood volume and duration best, respectively. Various copula families, including elliptical and Archimedean, are assessed, where Clayton copula emerge as the most suitable. This analysis demonstrates that when more flood features are considered together, the return period increases, indicating the reduced likelihood of occurrence. The trivariate case of the AND-joint return period surpasses the trivariate case of the OR-joint return period where the TP, V, DAND=5, 405.93 years, while TP, V, DOR=500.46 years. This comprehensive approach enhances hydrological modeling and decision-making for water resource management and flood mitigation projects.

Combining a hydrological model with ecological planning for optimal placement of water-sensitive solutions

Newer water management approaches aim to better utilize runoff by treating it as a resource rather than a nuisance and by promoting a more holistic handling of runoff. These approaches use nature-based green infrastructure solutions to increase infiltration and detain water. Identifying optimal placement for these solutions is challenging due to multiple and sometimes competing objectives. Here, we propose a methodology to help planners and stakeholders maximize the benefits of flood mitigation projects by identifying opportunities for sustainable development. Most studies examine placement decisions based on metrics obtained from hydrological models. However, solely depending on hydrological indicators, without accounting for social and ecological indicators, might bias the placement decisions. We propose combining hydrological and land-use planning models. We used the revised version of the Soil and Water Assessment Tool (SWAT) known as SWAT+ to simulate existing hydrological conditions and the results as initial input for the conservation decision support software MARXAN. We added data on endangered species and distance from the human population as ecological and social indicators. This addition shifted the selected areas and provided a more complete view of runoff management than only hydrological indicators. Furthermore, we show that coupling SWAT+ and MARXAN can effectively balance hydrological concerns with ecological and social factors.

Material quantities and estimated construction costs for new elevated IRC 2015-compliant single-family home foundations

Residential foundation selection is critical for the lifetime performance of the project, but the type of foundation selected can depend on cost. This study aims to compare the new construction costs of residential slab-on-fill and four types of crawl space foundations for residential projects by quantifying the material quantities for each and exploring the effect of building characteristics on material quantities and total costs. The building characteristics selected are size (139 m2, 186 m2, and 232 m2), footprint aspect ratio (1:1, 1:2.5, and 1:5) and first floor elevation (0 m–1.2 m in 0.3 m increments). We find that material quantities and total costs change not only with building size and elevation, but also with footprint aspect ratio. Applying 2022 RSMeans Building Construction Cost data, the results show that for any building size, aspect ratio, or elevation, raised wood flooring on pier foundations ($118–$180 per m2) and slab on fill ($103–$211 per m2) are the least expensive, while crawl space foundations with stemwalls are the most expensive ($147–$280 per m2). The results of this study can be used by residential builders, developers and designers in evaluating foundation costs and design alternatives. The methodology may also be adapted for use in other applications such as flood mitigation or energy efficiency projects or environmental sustainability assessments.

Stakeholder Perceptions about Incorporating Externalities and Vulnerability into Benefit–Cost Analysis Tools for Watershed Flood Risk Mitigation

Multi-scalar climate hazards in watersheds and growing consideration regarding equity call for innovation in how agencies evaluate and prioritize mitigation and adaptation projects. Benefit–Cost Analysis (BCA) is one approach that is increasingly being applied to decision-making (i.e., FEMA BCA toolkit), but that has not been applied to watershed and equity-based flood management initiatives. This paper addresses this topic and presents a case study evaluating projects for watershed flood and climate mitigation projects by the Louisiana Watershed Initiative (Louisiana, USA). Through semi-structured interviews with stakeholders and practitioners, we found that BCA tool design must be embedded in the program and policy in order to be successfully applied and that equity has not traditionally been a core value of mitigation practice. Even though many stakeholders understand the need for incorporating environmental and social project consequences at a watershed scale, challenges to doing so include inequitable barriers to project design in competitive processes, the complexity of integrating modeling and environmental outcomes data, jurisdictional interests, and the need for better science communication with local decision-makers.

Flood vulnerability assessment in the Jamuna river floodplain using multi-criteria decision analysis: A case study in Jamalpur district, Bangladesh

Flood is one of the most common hazards in many countries, affecting both life and properties. The recent climatic changes have brought a rise in both flood frequency and intensity making this phenomenon more devastating to people. Especially, the riparian communities of Jamalpur along the Jamuna river suffer at least once every year accounting for this natural hazard. In a scenario like this, precaution is a crucial task to fight against this natural phenomenon. Therefore, this study attempts to identify the flood vulnerable zones of Jamalpur district situating beside Jamuna river with a multi-criteria analysis. Assessment of flood vulnerability included consideration of physical indicators like rainfall, drainage density, distance from river, slope, land use land cover, elevation, soil classes as well as social indicators like population density, female density, literacy rate, number of shelters, unmetalled road and number of health personnel. All these parameters were analyzed in Geographic Information System (GIS) and assigned weightage with a multi-criteria decision-making technique namely- Analytic Hierarchy Process (AHP). Finally, a flood vulnerability map was generated for the seven Upazilas of Jamalpur district. Very high, high, moderate and low vulnerable zones were identified after overlaying all physical and social indicator maps under consideration. 45.96% portion of a total of 2115.2 sq. Km. Area was under very high and highly vulnerable zones in the final vulnerability map of Jamalpur. Such type of assessment process is significant for flood mitigation projects with a view to providing the greatest concern to the most vulnerable zones. The vulnerability maps can also help the policymakers to provide emergency aids and other privileges to those who are in most need of it.

Physical Simulation to Determine the Surface Water Profiles and Point Velocities for The Flow Conditions of Sungai Bunus Stilling

Overthe years, Sungai Bunus has undergone hydrological changes and has become lower and narrower. Under a flood mitigation project, a flood diversion channel is proposed to reduce the volume of water in Sungai Bunusfurthermore avoid the spill over into Sungai Klang and reduce flooding events in Kuala Lumpur city. This research describes the physical modelling of the flow state of the Sungai Bunus stilling basin. Physical model was constructed to verify the design criteria of the stilling basin that will be adopted for construction. Experimental work has been carried out both with and without piers under three specified discharges (52 L/s, 86 L/s and 121 L/s) and subsequently the measurement of the water surface height profiles and point velocities through the proposed system. Consequently, there are no significant differences of outcomes between the two circumstances. The results show that there is no overflow of water at discharges of 52 L/s and 86 L/s. The water level at the Sungai Bunus section starts to flood on one side of the package when the flowrate is 121 L/s both scenarios. All test conditions with and without piers shown that the point velocity measured at the beginning of the stilling basin (inlet) is much lower than the point velocity reported near the end of the stilling basin (outlet).

Problems and Solutions for the Flood Control Program in Medan City and its Surroundings

Medan City is currently experiencing flooding and this indicates all existing flood control projects implemented over the years have been unsuccessful. Therefore, the main objective of this research is to determine the best solution to overcome floods in the city through a literature study supplemented by a perception survey. The steps implemented include discovering the causes of the flood, determining the failure of the past flood control projects, disclosing the perception of the people affected by floods toward the city government’s commitment, and formulating the best solution to overcome the flood. It was discovered that there are two kinds of floods in Medan city which include the flash/river and the local/residence floods. The flash type was caused by the deforestation in the upstream area of the rivers flowing through the city while the local type is associated with high rainfall, lack of pervious area, and poor urban stormwater management. Moreover, the existing flood mitigation projects were observed to be unsuccessful because they applied the old paradigm with a normalization approach without compensating for the increase in the runoff discharge. This means there is a need to establish naturalization in the upper region of all rivers flowing through the city to reduce river flooding. The maintenance of the existing urban drainage system also needs to be combined with sustainable programs such as storing, absorbing, and reusing strategies to mitigate residence flooding. Furthermore, ten recommendations were proposed to stakeholders to overcome or significantly reduce flooding in Medan City and its surroundings. The first is the alignment of paradigms among stakeholders toward flood management while the last is completing related regulations and law enforcement.

Analysis, prioritization and strategic planning of flood mitigation projects based on sustainability dimensions and a spatial/value AHP-GIS system

Floods are among the most devastating consequences of global warming and can cause unprecedented disruptions in the operations of contemporary cities. Moreover, the sustainability of the limited water resources calls for a well-defined decision-making framework that facilitates the implementation of available measures. This study aims to establish a set of criteria for the comprehensive urban flood risk assessment and the creation of a prioritization map of flood mitigation projects. The proposed model is based on spatial data and expert opinions and is used for the flood vulnerability assessment and the project mitigation prioritization. The notion of vulnerability is decomposed on eighteen multidimensional factors which are also clustered under the so-called sustainability pillars; that is the environment, the society and the economy. In a second stage an Analytical Hierarchy Process (AHP) framework is coupled with a spatial database environment generated by a Geographic Information Systems (GIS) software and the outcome of the aforementioned process is included in a vulnerability map. The latter allows for the hierarchical grouping of the ranked future flood mitigation projects. Finally, spatial sensitivity analysis is conducted over the selected parameters and the effects on the resulting hierarchy are discussed.

Impact of Flood Mitigation Project on the River Water Salinity

The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Salinity intrusion was simulated in the study area by 1D numerical model. A 1-D hydrodynamic model coupled with a salinity model was used to analyze the salinity intrusion within Chukai River after the implementation of the flood mitigation project. The model was calibrated and validated using the data measured in Chukai River at 3 points from January 2007 until August 2013. Water quality simulation of salinity has been carried out once an excellent hydrodynamic model was established. The simulated river flow was reasonably matched to the measured data with R2 value 0.88, 0.92 and 0.82, respectively. Results suggest that after the realignment of Chukai River, the seawater intrudes further to the upstream river, causing the increasing salinity in the river about 10 - 15 ppt. However, with the floodway development, the channel would allow more water from Kemaman River being discharged into Chukai River. Increased in the volume of water in Chukai River has led to seawater dilution. Further, it invades the unique stretch of Chukai River and takes the salinity back to the initial state. Findings from the implementation of the flood mitigation project in the Kemaman river basin has benefitted the local society, watershed, and the surrounding biota ecosystems. Importantly, a greater prevention with the risk of repetitive flood damage to the buildings and structures in Kemaman area which has significantly achievable.
 HIGHLIGHTS
 
 Salinity model is used for flood mitigation project
 High salinity in Chukai river resulted from seawater intrusion
 Hydrodynamic model is to assess the water quality simulation

Community-based climate change adaptation and disaster risk mitigation in the Mekong Delta by the transdisciplinary approach

The article is based on data from the research program "Greater Mekong Sub-region Flood and Drought Risk Management and Mitigation Project (ADB-GMS1)" jointly implemented by the Asian Development Bank (ADB) and the Ministry of Agriculture and Rural Development, and the Vietnam Institute of Water Resources Research in Tien Giang and Dong Thap province. The results show that, in recent years, due to the increasingly severe global climate change, the intensity of various types of natural disasters occurs more frequently, irregularly and with greater intensity. This has greatly affected the production, daily life and properties of the people in the vulnerable areas. To reduce the impact of various types of disasters on people living in vulnerable areas, it is necessary to combine two types of solutions in disaster prevention, namely construction solutions and non- construction solutions. In which, non-construction solutions play a very important role, namely, people living in communities are considered as the main actors in preventing and mitigating disaster risks occurring in the community.

Analysis, Prioritization and Strategic Planning of Flood Mitigation Projects Based on Sustainability Dimensions and a Spatial/Value Ahp-Gis System

Analysis, Prioritization and Strategic Planning of Flood Mitigation Projects Based on Sustainability Dimensions and a Spatial/Value Ahp-Gis System

Optimizing Land Use and Land Cover Allocation for Flood Mitigation Using Land Use Change and Hydrological Models with Goal Programming, Chaiyaphum, Thailand

Floods represent one of the most severe natural disasters threatening the development of human society worldwide, including in Thailand. In recent decades, Chaiyaphum province has experienced a problem with flooding almost every year. In particular, the flood in 2010 caused property damage of 495 million Baht, more than 322,000 persons were affected, and approximately 1046.4 km2 of productive agricultural area was affected. Therefore, this study examined how to optimize land use and land cover allocation for flood mitigation using land use change and hydrological models with optimization methods. This research aimed to allocate land use and land cover (LULC) to minimize the surface for flood mitigation in Mueang Chaiyaphum district, Chaiyaphum province, Thailand. The research methodology consisted of six stages: data collection and preparation, LULC classification, LULC prediction, surface runoff estimation, the optimization of LULC allocation for flood mitigation and mapping, and economic and ecosystem service value evaluation and change. According to the results of the optimization and mapping of suitable LULC allocation to minimize surface runoff for flood mitigation in dry, normal, and wet years using goal programming and the CLUE-S model, the suitable LULC allocation for flood mitigation in 2049 under a normal year could provide the highest future economic value and gain. In the meantime, the suitable LULC allocation for flood mitigation in 2049 under a drought year could provide the highest ecosystem service value and gain. Nevertheless, considering future economic and ecosystem service values and changes with surface runoff reduction, the most suitable LULC allocation for flood mitigation is a normal year. Consequently, it can be concluded that the derived results of this study can be used as primary information for flood mitigation project implementation. Additionally, the presented conceptual framework and research workflows can be used as a guideline for government agencies to examine other flood-prone areas for flood mitigation in Thailand.

Flood Mitigation in Mediterranean Coastal Regions: Problems, Solutions, and Stakeholder Involvement

Flooding affects Mediterranean coastal areas, with negative impacts on regional populations and ecosystems. This paper reviews the causes and consequences of coastal flooding in European Mediterranean countries, common and advanced solutions implemented to mitigate flood risk, and the importance of stakeholder involvement in developing these solutions. Climate change, intensive urbanization, tourism, deforestation, wildfires, and erosion are the main causes of coastal flooding, leading to social and economic losses, degradation of ecosystems, and water and soil contamination due to saltwater intrusion. Various measures for mitigating urban coastal flooding have been implemented, including coastal barriers, infrastructural drainage systems, wetlands, and mobile dams. Development and implementation of such solutions should be performed in close collaboration with stakeholders, but their current engagement at the coordination and/or decision-making level does not allow full integration of local knowledge in flood mitigation projects. Various processes are used to engage stakeholders in coastal flood mitigation, but participatory approaches are required to integrate their perspectives into performance analysis of potential solutions. Such approaches would allow a balance to be reached between nature conservation, market forces, stakeholder needs, and decision-makers’ priorities, resulting in development of innovative and sustainable mitigation solutions to enhance urban resilience to coastal flooding.

Social innovation in times of flood and eviction crisis: The making and unmaking of homes in the Ciliwung riverbank, Jakarta

This study considers displacement occurring around the Jakarta flood mitigation projects between 2015–17 and explores the emergence of social innovation by affected kampung communities along the Ciliwung River. A framework combining theories on domicide and social innovation is developed to scrutinize two main case studies, Bukit Duri and Kampung Tongkol, revealing their connection to the city's urban development trajectory as well as the continuous struggle over adequate housing for low‐income groups. The study questions official plans, policies and responses towards flood‐induced displacement and resettlement planning. It also brings social innovation into the debate to unpack how displacement became a key moment for transformative change. The paper argues that, although urban eviction is related to globalization, outcomes are not foreclosed. Predominant urban mechanisms are contested, shaped, and transformed by local communities.

An investigation on the non-stationarity of flood frequency across the UK

Water infrastructure design and flood mitigation projects are currently based on a so-called stationary assumption. However, this assumption has been challenged in recent years due to increased extreme weather, potentially leading to the underestimation of flood quantiles and an increased risk of structural failures. In the present study, peak flow series from 158 gauging stations in the UK are analysed using both stationary and non-stationary models based on the generalised additive models for location, scale and shape (GAMLSS) framework. Nine candidate covariates are used for non-stationary models to obtain information on the significant drivers of non-stationarity in each flood series. Very few stations are thus found to show temporal trends, which suggests that time-varying non-stationary flood models may not always be suitable, and the use of physically-based covariates can provide better-fitting models. In particular, the non-stationary models using rainfall-related covariates display the best performance for the vast majority of stations, thus suggesting that the variability of the rainfall regime remains the dominant driver for changes in flooding. Moreover, two atmospheric circulation patterns, namely the North Atlantic Oscillation (NAO) and the East Atlantic Pattern, were found to be closely related to the non-stationarity of flooding at a number of stations. Unlike rainfall, however, the influence of these climate indices is not particularly dominant; hence, they are more suitably employed as components of a multiple-covariate non-stationary model. Besides, a direct linkage between the variability of flooding and climate changes has not been identified either regionally or globally. For the majority of stations (70%), the use of multiple covariates can provide a better non-stationary model than the use of a single covariate.