Climate Justice Planning in Global South: Applying a Coupled Nature–Human Flood Risk Assessment Framework in a Case for Ho Chi Minh City, Vietnam

Developing countries in the global south that contribute less to climate change have suffered greater from its impacts, such as extreme climatic events and disasters compared to developed countries, causing climate justice concerns globally. Ho Chi Minh City has experienced increased intensity and frequency of climate change-induced urban floods, causing socio-economic damage that disturbs their livelihoods while urban populations continue to grow. This study aims to establish a citywide flood risk map to inform risk management in the city and address climate justice locally. This study applied a flood risk assessment framework integrating a coupled nature–human approach and examined the spatial distribution of urban flood hazard and urban flood vulnerability. A flood hazard map was generated using selected morphological and hydro-meteorological indicators. A flood vulnerability map was generated based on a literature review and a social survey weighed by experts’ priorities using the Fuzzy Delphi Method and Analytic Network Process. Vulnerability indicators including demographic characteristics, infrastructure, and land use patterns were used to generate a flood vulnerability map. The results illustrate that almost the entire central and northeastern parts of the city are at high flood risk, whereas the western part is at low flood risk. The findings have implications in urban planning via identifying risk hot spots in order to prioritize resources for mitigating hazards and enhancing community resilience to urban floods.

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Flood Hazard, Vulnerability and Risk Assessment for Different Land Use Classes Using a Flow Model

Earth Systems and Environment ◽

10.1007/s41748-019-00141-w ◽

2019 ◽

Vol 4 (1) ◽

pp. 225-244 ◽

Cited By ~ 5

Author(s):

Md Abdullah Al Baky ◽

Muktarun Islam ◽

Supria Paul

Keyword(s):

Risk Assessment ◽

Critical Point ◽

Return Period ◽

Flood Risk ◽

Flood Hazard ◽

Flow Simulation ◽

Flood Risk Assessment ◽

Damage Functions ◽

Flood Vulnerability ◽

Different Levels

AbstractThis study is concerned with flood risk that can be assessed by integrating GIS, hydraulic modelling and required field information. A critical point in flood risk assessment is that while flood hazard is the same for a given area in terms of intensity, the risk could be different depending on a set of conditions (flood vulnerability). Clearly, risk is a function of hazard and vulnerability. This study aims to introducing a new approach of assessing flood risk, which successfully addresses this above-mentioned critical issue. The flood risk was assessed from flood hazard and vulnerability indices. Two-dimensional flood flow simulation was performed with Delft3D model to compute floodplain inundation depths for hazard assessment. For the purpose of flood vulnerability assessment, elements at risk and flood damage functions were identified and assessed, respectively. Then, finally flood risk was assessed first by combining replacement values assessed for the elements and then using the depth–damage function. Applying this approach, the study finds that areas with different levels of flood risk do not always increase with the increase in return period of flood. However, inundated areas with different levels of flood depth always increase with the increase in return period of flood. The approach for flood risk assessment adopted in this study successfully addresses the critical point in flood risk study, where flood risk can be varied even after there is no change in flood hazard intensity.

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Topography- and nightlight-based national flood risk assessment in Canada

10.5194/hess-2016-524 ◽

2016 ◽

Author(s):

Amin Elshorbagy ◽

Anchit Lakhanpal ◽

Bharath Raja ◽

Serena Ceola ◽

Alberto Montanari ◽

...

Keyword(s):

Flood Risk ◽

Flood Hazard ◽

Hazard Mapping ◽

Hazard Map ◽

Flood Risk Assessment ◽

Risk Map ◽

National Scale ◽

Digital Elevation ◽

The City ◽

Flood Risk Map

Abstract. In Canada, flood analysis and water resource management, in general, are tasks conducted at the provincial level; therefore, unified national-scale approaches to water-related problems are uncommon. In this study, a national-scale flood risk assessment approach is proposed and developed. The study focuses on using global and national datasets available at reasonably fine resolutions to create flood risk maps. First, a flood hazard map of Canada is developed using topography-based parameters derived from digital elevation models namely Elevation Above Nearest Drainage (EAND) and Distance From Nearest Drainage (DFND). This flood hazard mapping method is tested on a smaller area around the city of Calgary, Alberta, against a flood inundation map produced by the City using hydraulic modeling. Second, a flood exposure map of Canada is developed using a land-use map and the satellite-based nightlight luminosity data as two exposure parameters. Third, an economic flood risk map is produced, and subsequently overlaid with population density information to produce a socioeconomic flood risk map for Canada. All three maps of hazard, exposure, and risk are classified into five classes, ranging from very low to severe. A simple way to include flood protection measures in hazard estimation is also demonstrated using the example of the city of Winnipeg, Manitoba. This could be done for the entire country if information on flood protection across Canada were available. The evaluation of the flood hazard map shows that the topography-based method adopted in this study is both practical and reliable for large-scale analysis. Sensitivity analysis regarding the resolution of the digital elevation model is needed to identify the resolution that is fine enough for reliable hazard mapping, but coarse enough for computational tractability. The nightlight data are found to be useful for exposure and risk mapping in Canada; however, uncertainty analysis should be conducted to investigate the effect of the overglow phenomenon on flood risk mapping.

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Urban Flood Risk Assessment: Integration of Decision Making and Machine Learning

10.20944/preprints202201.0133.v1 ◽

2022 ◽

Author(s):

Fereshteh Taromideh ◽

Ramin Fazloula ◽

Bahram Choubin ◽

Alireza Emadi ◽

Ronny Berndtsson

Keyword(s):

Machine Learning ◽

Decision Making ◽

Flood Risk ◽

Flood Hazard ◽

Hazard Maps ◽

Risk Map ◽

Flood Vulnerability ◽

Urban Flood ◽

Machine Learning Methods ◽

Urban Flood Risk

Urban flood risk mapping is an important tool for the mitigation of flooding in view of human activities and climate change. Many developing countries, however, lack sufficiently detailed data to produce reliable risk maps with existing methods. Thus, improved methods are needed that can improve urban flood risk management in regions with scarce hydrological data. Given this, we estimated the flood risk map for Rasht City (Iran), applying a composition of decision-making and machine learning methods. Flood hazard maps were produced applying six state-of-the-art machine learning algorithms such as: classification and regression trees (CART), random forest (RF), boosted regression trees (BRT), multivariate adaptive regression splines (MARS), multivariate discriminant analysis (MDA), and support vector machine (SVM). Flood conditioning parameters applied in modeling were elevation, slope angle, aspect, rainfall, distance to river (DTR), distance to streets (DTS), soil hydrological group (SHG), curve number (CN), distance to urban drainage (DTUD), urban drainage density (UDD), and land use. In total, 93 flood location points were collected from the regional water company of Gilan province combined with field surveys. We used the Analytic Hierarchy Process (AHP) decision-making tool for creating an urban flood vulnerability map, which is according to population density (PD), dwelling quality (DQ), household income (HI), distance to cultural heritage (DTCH), distance to medical centers and hospitals (DTMCH), and land use. Then, the urban flood risk map was derived according to flood vulnerability and flood hazard maps. Evaluation of models was performed using receiver-operator characteristic curve (ROC), accuracy, probability of detection (POD), false alarm ratio (FAR), and precision. The results indicated that the CART model is most accurate model (AUC = 0.947, accuracy = 0.892, POD = 0.867, FAR = 0.071, and precision = 0.929). The results also demonstrated that DTR, UDD, and DTUD played important roles in flood hazard modeling; whereas, the population density was the most significant parameter in vulnerability mapping. These findings indicated that machine learning methods can improve urban flood risk management significantly in regions with limited hydrological data.

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Assessment of Community Vulnerability to Different Types of Urban Floods: A Case for Lishui City, China

Sustainability ◽

10.3390/su12197865 ◽

2020 ◽

Vol 12 (19) ◽

pp. 7865 ◽

Cited By ~ 1

Author(s):

Quntao Yang ◽

Shuliang Zhang ◽

Qiang Dai ◽

Rui Yao

Keyword(s):

Urban Areas ◽

Flood Hazard ◽

Urban Flooding ◽

Urban Floods ◽

Flood Vulnerability ◽

Urban Flood ◽

Indicator Method ◽

Comprehensive Method ◽

Different Types ◽

Hydrometeorological Conditions

Urban flooding is a severe and pervasive hazard caused by climate change, urbanization, and limitations of municipal drainage systems. Cities face risks from different types of floods, depending on various geographical, environmental, and hydrometeorological conditions. In response to the growing threat of urban flooding, a better understanding of urban flood vulnerability is needed. In this study, a comprehensive method was developed to evaluate the vulnerability of different types of urban floods. First, a coupled urban flood model was built to obtain the extent of influence of various flood scenarios caused by rainfall and river levee overtopping. Second, an assessment framework for urban flood vulnerability based on an indicator method was used to evaluate the vulnerability in different flood hazard scenarios. Finally, the method was applied to Lishui City, China, and the distribution and pattern of urban flood vulnerability were studied. The results highlight the spatial variability of flooding and the vulnerability distributions of different types of urban floods. Compound floods were identified to cause more severe effects in the urban areas.

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Flood Risk Assessment Based on Flood Hazard and Vulnerability Indexes

Ovidius University Annals of Constanta - Series Civil Engineering ◽

10.2478/ouacsce-2020-0014 ◽

2020 ◽

Vol 22 (1) ◽

pp. 127-137

Author(s):

Constantin Buta ◽

Geanina Mihai ◽

Madalina Stănescu

Keyword(s):

Risk Assessment ◽

Flood Risk ◽

Damage Assessment ◽

Flood Hazard ◽

Risk Index ◽

Population Based ◽

Flood Risk Assessment ◽

Integrated Planning ◽

Urban Floods ◽

Sectoral Planning

Abstract Within this paper, a methodology for assessing the flood risk was developed by extracting the essential factors that favor the generation of flood risk. These factors, that had a sufficient number of data for a proper comparative analysis, are: potentially affected population based on population density, total agricultural area, total built-up area and the historical maximum amount of precipitation recorded in 24 hours. The flood risk assessment is presented in the form of indices calculation for all these factors and maps generated which representing the results of the calculation of the above-mentioned factors and the results of the flood risk index calculation. Urban floods have particularities that must be presented in detail to understand the flood phenomenon, which is why this paper takes into consideration these areas. In order to determine the probability of urban floods, all disturbing factors that may affect the urban area must be taken into account. The method presented in this paper can be used in sectoral planning activities and integrated planning studies, and for damage assessment.

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Topography- and nightlight-based national flood risk assessment in Canada

Hydrology and Earth System Sciences ◽

10.5194/hess-21-2219-2017 ◽

2017 ◽

Vol 21 (4) ◽

pp. 2219-2232 ◽

Cited By ~ 10

Author(s):

Amin Elshorbagy ◽

Raja Bharath ◽

Anchit Lakhanpal ◽

Serena Ceola ◽

Alberto Montanari ◽

...

Keyword(s):

Flood Risk ◽

Flood Hazard ◽

Hazard Mapping ◽

Hazard Map ◽

Flood Risk Assessment ◽

Risk Map ◽

National Scale ◽

Digital Elevation ◽

The City ◽

Flood Risk Map

Abstract. In Canada, flood analysis and water resource management, in general, are tasks conducted at the provincial level; therefore, unified national-scale approaches to water-related problems are uncommon. In this study, a national-scale flood risk assessment approach is proposed and developed. The study focuses on using global and national datasets available with various resolutions to create flood risk maps. First, a flood hazard map of Canada is developed using topography-based parameters derived from digital elevation models, namely, elevation above nearest drainage (EAND) and distance from nearest drainage (DFND). This flood hazard mapping method is tested on a smaller area around the city of Calgary, Alberta, against a flood inundation map produced by the city using hydraulic modelling. Second, a flood exposure map of Canada is developed using a land-use map and the satellite-based nightlight luminosity data as two exposure parameters. Third, an economic flood risk map is produced, and subsequently overlaid with population density information to produce a socioeconomic flood risk map for Canada. All three maps of hazard, exposure, and risk are classified into five classes, ranging from very low to severe. A simple way to include flood protection measures in hazard estimation is also demonstrated using the example of the city of Winnipeg, Manitoba. This could be done for the entire country if information on flood protection across Canada were available. The evaluation of the flood hazard map shows that the topography-based method adopted in this study is both practical and reliable for large-scale analysis. Sensitivity analysis regarding the resolution of the digital elevation model is needed to identify the resolution that is fine enough for reliable hazard mapping, but coarse enough for computational tractability. The nightlight data are found to be useful for exposure and risk mapping in Canada; however, uncertainty analysis should be conducted to investigate the effect of the overglow phenomenon on flood risk mapping.

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1D-2D MODELING OF URBAN FLOODS AND RISK MAP GENERATION FOR THE PART OF HYDERABAD CITY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-5-445-2018 ◽

2018 ◽

Vol XLII-5 ◽

pp. 445-450 ◽

Cited By ~ 2

Author(s):

V. A. Rangari ◽

R. Gonugunta ◽

N. V. Umamahesh ◽

A. K. Patel ◽

C. M. Bhatt

Keyword(s):

Flood Risk ◽

Flood Hazard ◽

Extreme Rainfall ◽

Storm Water ◽

Urban Flooding ◽

Flood Inundation ◽

Urban Floods ◽

Urban Flood ◽

Extreme Flood ◽

Risk Maps

<p><strong>Abstract.</strong> Space for water is now becoming guiding principle of urban planning because urban flooding is the major problem facing by most of the cities in India. Urban development in developing countries like India usually occurs with high population concentrating in small areas, with poor drainage conditions. People occupy floodplain areas in low flood years and when larger flood occurs it causes high damage. The origin for urban floods is floodplains encroachment and unplanned drainage systems. Complexities in the urban environment and drainage infrastructure have an inherent influence on surface runoff. This runoff generates urban flooding which poses challenges to modeling urban flood hazard and risk. As like in river flooding satellite images are not available for unban flooding scenario. So better modelling provides minimizing loss of life and property. The present study focuses on recognizing the highly effected areas which are liable to flooding when extreme rainfall occurs for part of Hyderabad city (Zone XIII). The entire Hyderabad city is divided into 16 zones and each zone having details of existing drain network. A coupled 1D-2D flood modelling approach is used to identify flood prone areas and develop flood inundation and flood risk maps. 1D model for pilot area is developed using storm water management model (SWMM) and coupled with 2D PCSWMM. A web based GIS platform INPPINS is used to geo reference the existing network details and exported to 1D SWMM model. The model is simulated for extreme flood event occurred in past. The simulation run results identifies overflowing drainage nodes and flood inundation maps and risk maps prepared. The flood risk maps identify the low lying areas which need immediate attention in case of emergency. The overflowing nodes suggest the need of improvement of drainage in the area to safely dispose of the storm water and minimize the flooding.</p>

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A Framework for Risk-Based Assessment of Urban Floods in Coastal Cities

10.21203/rs.3.rs-547336/v1 ◽

2021 ◽

Author(s):

M. Dinesh Kumar ◽

Shubham Tandon ◽

Nitin Bassi ◽

Pradipta Kumar Mohanty ◽

Saurabh Kumar ◽

...

Keyword(s):

High Risk ◽

Flood Risk ◽

Risk Index ◽

Progressive Increase ◽

Urban Floods ◽

Urban Flood ◽

Coastal Cities ◽

Index Value ◽

The City ◽

Urban Flood Risk

Abstract Many coastal cities in developing countries are at the risk of flooding due to a progressive increase in the built-up areas and poor management of stormwater. The flooding situation in coastal cities gets accentuated further due to climate induced natural disasters such as cyclones and climate change induced sea-level rise that adversely impact the city’s natural drainage potential. This study developed a composite urban flood risk index consisting of three sub-indices and 20 key natural, physical, social, and economic influencing variables for a coastal city (i.e. Cuttack) in eastern India, the intensity of storm runoff being one among the many. The intensity-duration-frequency curve developed shows that the city can experience floods with a peak discharge of 1,320 cubic metre per second every alternate year for a rainfall intensity of 2-hour duration. The urban flood risk index computed for all the city wards shows that out of the 59 wards, only one ward has low flood risk (index value < 0.40) and 20 wards are at high risk (index value 0.55 and above) from the urban flood. Thereafter, factors leading to high risk due to urban floods were identified and the institutional capacities available with the urban utility for fighting floods analyzed.

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Effectiveness of Nature-Based Solutions on Pluvial Flood Hazard Mitigation: The Case Study of the City of Eindhoven (The Netherlands)

Resources ◽

10.3390/resources10030024 ◽

2021 ◽

Vol 10 (3) ◽

pp. 24

Author(s):

Sandra Costa ◽

Rik Peters ◽

Ricardo Martins ◽

Luuk Postmes ◽

Jan Jacob Keizer ◽

...

Keyword(s):

The Netherlands ◽

Flood Risk ◽

Hydrological Cycle ◽

Risk Mitigation ◽

Flood Hazard ◽

Urban Flood ◽

Storm Intensity ◽

Impervious Area ◽

Urban Catchments ◽

The City

Urbanization leads to changes in the surface cover that alter the hydrological cycle of cities, particularly by increasing the impervious area and, thereby, reducing the interception, storage and infiltration capacity of rainwater. Nature-based solutions (NBS) can contribute to flood risk mitigation in urbanized areas by restoring hydrological functions. However, the effects of NBS on flood risk mitigation are complex and can differ substantially with the type of the NBS. Therefore, the effectiveness of NBS at the urban catchment scale is still subject to much debate, especially at the scale of urban catchments. In this study, the effects of different NBS on urban flood mitigation were evaluated for the city of Eindhoven in The Netherlands, as it has a history of urban flood events. To this end, various NBS scenarios were defined by municipal stakeholders and their impacts modelled with the numerical model Infoworks ICM. This was done for design storms with short, medium and long return periods (5, 10 and 100 years). Overall, the simulated NBS were effective in flood risk mitigation, reducing the flooded area as well as flood depth. The effectiveness of the individual NBS scenarios, however, depended strongly on the location and extension of the NBS, as well as on storm intensity. The effectiveness tended to increase with the increase in NBS surface area, while it tended to decrease with increasing storm intensity and, hence, return period. The NBS solution increasing street water storage was revealed to be more effective than those involving green car parks and green roofs. This study showed that numerical flooding models can be useful tools to assess the effects of NBS to reduce flood extent, water depth and/or velocity, providing insights that can support city planners to design and compare alternative strategies and plans for urban flood risk mitigation.

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A Case Study of Flood Risk Evaluation Based on Emergy Theory and Cloud Model in Anyang Region, China

Water ◽

10.3390/w13040420 ◽

2021 ◽

Vol 13 (4) ◽

pp. 420

Author(s):

Zening Wu ◽

Yuhai Cui ◽

Yuan Guo

Keyword(s):

Risk Assessment ◽

Flood Risk ◽

Flood Control ◽

Flood Hazard ◽

Cloud Model ◽

Flood Disaster ◽

Assessment System ◽

Assessment Model ◽

Flood Risk Assessment ◽

Emergy Theory

With the progression of climate change, the intensity and frequency of extreme rainfall have increased in many parts of the world, while the continuous acceleration of urbanization has made cities more vulnerable to floods. In order to effectively estimate and assess the risks brought by flood disasters, this paper proposes a regional flood disaster risk assessment model combining emergy theory and the cloud model. The emergy theory can measure many kinds of hazardous factor and convert them into unified solar emergy (sej) for quantification. The cloud model can transform the uncertainty in flood risk assessment into certainty in an appropriate way, making the urban flood risk assessment more accurate and effective. In this study, the flood risk assessment model combines the advantages of the two research methods to establish a natural and social dual flood risk assessment system. Based on this, the risk assessment system of the flood hazard cloud model is established. This model was used in a flood disaster risk assessment, and the risk level was divided into five levels: very low risk, low risk, medium risk, high risk, and very high risk. Flood hazard risk results were obtained by using the entropy weight method and fuzzy transformation method. As an example for the application of this model, this paper focuses on the Anyang region which has a typical continental monsoon climate. The results show that the Anyang region has a serious flood disaster threat. Within this region, Linzhou County and Anyang County have very high levels of risk for flood disaster, while Hua County, Neihuang County, Wenfeng District and Beiguan District have high levels of risk for flood disaster. These areas are the core urban areas and the economic center of local administrative regions, with 70% of the industrial clusters being situated in these regions. Only with the coordinated development of regional flood control planning, economy, and population, and reductions in the uncertainty of existing flood control and drainage facilities can the sustainable, healthy and stable development of the region be maintained.

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