A risk assessment for major river flooding in Myanmar incorporating hazard, exposure, and vulnerability

2021 ◽  
Author(s):  
Hnin Wuit Yee Kyaw ◽  
Alexandra Dudley
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
Flood Risk ◽  
Flood Events ◽  
High Exposure ◽  
River Flooding ◽  
Hazard Exposure ◽  
Study Results ◽  
Entry Points ◽  
Major River

<p>Worldwide, floods have major impacts on people, economies, and the environment. In Myanmar, floods are the most frequently occurring hazard and have the highest contribution to average annual loss compared to all other hazards. Although the population has learned to adapt to yearly flooding, climate change exacerbates the frequency and magnitude of flood events to an extent where the population has little capacity to cope. Many factors such as poverty and dependency on agriculture make the Burmese people more vulnerable to major flood events. The need to better understand flood risk and its spatial patterns in Myanmar has become extremely important.</p><p>However, the state of the art on flood risk in Myanmar is not well developed. Analysis has mostly focused on flood loss, hazard, mitigation, and resilience, or future vulnerability to flooding. Here we present a comprehensive quantitative indicator-based risk assessment for a major flood event with a 100-year return period at the township level for Myanmar. This analysis will show the spatial distribution of major river flood risk based on the IPCC framing of risk while highlighting factors of vulnerability that contribute to risk. The analysis considered the present-day flood risk to people. Flood extent and population distribution were used to create a hazard/exposure indicator. Then, a systematic literature review was performed to identify relevant vulnerability indicators and drivers for Myanmar. Data for each vulnerability indicator was collected and compiled into one vulnerability index score. Then, we compared two different methods of aggregation of the elements into a risk index: multiplicative arithmetic aggregation and overlay of different quantiles of hazard/exposure and vulnerability. Post hoc analysis was conducted to test the relationship between elements for the multiplicative aggregation method.</p><p>The analysis showed that the highly exposed populations and townships are adjacent to rivers, with most flooding in the Ayeyarwady region. Major urban population centers such as Yangon and Mandalay cities have high exposure to flooding. Vulnerability to river flooding is primarily triggered by poverty, inadequate access to healthcare with a limited number of doctors and beds, poor road networks, and a small number of households with boats. Risk is highly concentrated in townships in the Ayeyarwady, Bago, and Rakhine regions in both aggregation methods.</p><p>Importantly, there are limitations in this study and future work could focus on addressing these gaps. For example, this assessment focused on a single hazard (flood) and a single exposed element (people) whereas Myanmar has a multi-hazard environment with complex social-ecological systems and high levels of resource dependency. Nevertheless, our study results remain essential for local and national authorities and related organizations in the field of disaster risk reduction as it has a strong conceptual foundation of risk with a clear focus on entry points for vulnerability and risk reduction.</p><p> </p><p> </p>

Flood risk assessment for Ecuador 

2021 ◽  
Author(s):  
Melisa Mena-Benavides ◽  
Manuel Urrutia ◽  
Konstantin Scheffczyk ◽  
Angel A. Valdiviezo-Ajila ◽  
Jhoyzett Mendoza ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
Flood Risk ◽  
Disaster Risk Reduction ◽  
Disaster Risk ◽  
Flood Frequency ◽  
Flood Risk Assessment ◽  
Essential Information ◽  
Synthetic Aperture Radar Data ◽  
Ecological Regions

<p>Understanding disaster risk is the first priority for action of the Sendai Framework for Disaster Risk Reduction (SFDRR) and is the essential information needed to guide disaster governance and achieve disaster risk reduction. Flooding is a natural hazard that causes the highest number of affected people due to disasters. In Ecuador from 1970 to 2019 flooding caused the highest amount of loss and damage to housing, and from 2016 to 2019 there were 1263 flood events reported. However, the differentiated impacts in flood exposed areas and what can be done to reduce risk and its impacts are still not well understood. In this research, we explored the different dimensions of flood risk, namely hazard, exposure, and vulnerability, and investigated the drivers of risk in different ecological regions of Ecuador. The assessment was conducted at the parish level, the smallest administrative scale, for three selected provinces of Bolivar, Los Ríos, and Napo, representing not only the country’s three main ecological regions but also commonly affected territories due to flooding. Using an automated flood detection procedure based on Sentinel-1 synthetic aperture radar data, flood hazard information was derived from flood frequency and flood depth for the years 2017, 2018, and 2019. The drivers of exposure and vulnerability were derived from scientific literature and further evaluated and complemented during a participatory workshop with over 50 local experts from the different regions. Centered on this exercise, an indicator library was created to inform the data selection from various sources and provides the basis for deriving a spatially explicit flood risk assessment using an indicator-based approach. Impact data are available to validate the risk assessment at the parish level and with this reveal key drivers of flood risk in different ecological regions of Ecuador. This information will provide the basis to derive targeted measures for disaster risk reduction.</p>

scholarly journals Flood Risk Assessment and Quantification at the Community and Property Level in the State of Iowa

2021 ◽  
Author(s):  
Enes Yildirim ◽  
Ibrahim Demir
Keyword(s):  
Risk Assessment ◽  
High Resolution ◽  
Flood Risk ◽  
Large Scale ◽  
Spatial Scales ◽  
The United States ◽  
Flood Risk Assessment ◽  
Study Region ◽  
Study Results ◽  
Flood Maps

Flood risk assessment contributes to identifying at-risk communities and supports mitigation decisions to maximize benefits from the investments. Large-scale risk assessments generate invaluable inputs for prioritizing regions for the distribution of limited resources. High-resolution flood maps and accurate parcel information are critical for flood risk analysis to generate reliable outcomes for planning, preparedness, and decision-making applications. Large-scale damage assessment studies in the United States often utilize the National Structure Inventory (NSI) or HAZUS default dataset, which results in inaccurate risk estimates due to the low geospatial accuracy of these datasets. On the other hand, some studies utilize higher resolution datasets, however they are limited to focus on small scales, for example, a city or a Hydrological United Code (HUC)-12 watershed. In this study, we collected extensive detailed flood maps and parcel datasets for many communities in Iowa to carry out a large-scale flood risk assessment. High-resolution flood maps and the most recent parcel information are collected to ensure the accuracy of risk products. The results indicate that the Eastern Iowa communities are prone to a higher risk of direct flood losses. Our model estimates nearly $10 million in average annualized losses, particularly in large communities in the study region. The study highlights that existing risk products based on FEMA's flood risk output underestimate the flood loss, specifically in highly populated urban communities such as Bettendorf, Cedar Falls, Davenport, Dubuque, and Waterloo. Additionally, we propose a flood risk score methodology for two spatial scales (e.g., HUC-12 watershed, property) to prioritize regions and properties for mitigation purposes. Lastly, the watershed-scale study results are shared through a web-based platform to inform the decision-makers and the public.

Evaluation of flood risk drivers as a tool to define municipal risk profiles

2020 ◽  
Author(s):  
Pedro Pinto Santos ◽  
Susana Pereira ◽  
José Luís Zêzere ◽  
Alexandre Oliveira Tavares ◽  
Eusébio Reis ◽  
...  
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Social Vulnerability ◽  
Methodological Approach ◽  
Risk Index ◽  
Slope Angle ◽  
Road Density ◽  
High Exposure ◽  
Hazard Exposure ◽  
Flood Susceptibility

<p>This work aims to compute a flood risk index (FRI) for the 278 Portuguese municipalities, designed to rank and characterize the drivers of fluvial flooding-related disasters (Santos et al., 2020). FRI is the product of hazard, exposure and vulnerability scores, where each factor is raised to 1/3, a solution also applied by the INFORM risk index to increase the dispersion of index values.</p><p>Hazard considers two variables: flood susceptibility (SUSCF), and the weather and climate events index (WCE) translating the frequency of the rainfall events that may generate peak flows. SUSCF is the product of stream flood susceptibility (SFS) (Santos et al., 2019) and the main flood-prone areas (MFPA). SFS considers flow accumulation, slope angle and relative permeability, accounting for the cumulative effect of these factors along the entire basins’ area. MPFA results from overlaying areas with slope angle ≤ 2º and areas with Height Above Nearest Drainage ≤ 2, only when they were topologically connected to streams with SFS > 5.</p><p>Exposure considers three variables: population density (PD), road density (RD) and the average degree of imperviousness (ADI). PD (inhab./km<sup>2</sup>) is based on the 2011 Census. RD (km/km<sup>2</sup>) is calculated from the OpenStreetMap<sup>©</sup> data. ADI is the municipal average value of the layer “IMD - Imperviousness Degree 2012 – 20 m resolution”, from the Copernicus Land Monitoring Service.</p><p>Vulnerability (V) is the product of criticality and support capability, where the latter acts by attenuating criticality, according to the methodology presented by Tavares et al. (2018) to assess social vulnerability.</p><p>The six core variables were scaled to the range [0, 1] following the max-min method. The respective weights were tested and selected according to the scientific literature, correlation and reliability tests.</p><p>Ward’s clustering classification was used to define seven clusters of municipalities, differing in the scores of hazard, exposure and vulnerability. While it is suggested that municipalities in some clusters would require interventions to reduce hazard, others should invest on medium to long-term measures that address high exposure and vulnerability. The results obtained with this methodological approach contribute to the diversification of flood risk management strategies.</p><p> </p><p>Acknowledgements:</p><p>This work was financed by national funds through FCT—Portuguese Foundation for Science and Technology, I.P., under the framework of the project BeSafeSlide‑Landslide Early Warning soft technology prototype to improve community resilience and adaptation to environmental change (PTDC/GES-AMB/30052/2017) and by the Research Unit UIDB/00295/2020. Pedro Pinto Santos is funded by FCT through the project with the reference CEEIND/00268/2017.</p><p> </p><p>References:</p><p>Santos, P.P., Pereira, S., Zêzere, J.L., Tavares, A.O., Reis, E., Garcia, R.A.C., Oliveira, S.C., 2019. A comprehensive approach to understanding flood risk drivers at the municipal level. J. Environ. Manage. https://doi.org/10.1016/j.jenvman.2020.110127</p><p>Santos, P.P., Reis, E., Pereira, S., Santos, M., 2019. A flood susceptibility model at the national scale based on multicriteria analysis. Sci. Total Environ. 667, 325–337. https://doi.org/10.1016/j.scitotenv.2019.02.328</p><p>Tavares, A.O., Barros, J.L., Mendes, J.M., Santos, P.P., Pereira, S., 2018. Decennial comparison of changes in social vulnerability: A municipal analysis in support of risk management. Int. J. Disaster Risk Reduct. 31, 679–690. https://doi.org/10.1016/J.IJDRR.2018.07.009</p>

scholarly journals Aggregated Risk Assessment and Survey for Risk Reduction in Oil Terminals

2021 ◽  
Vol 13 (21) ◽  
pp. 12169
Author(s):  
Robertas Alzbutas ◽  
Mindaugas Vaisnoras ◽  
Inga Saruniene ◽  
Ricardas Krikstolaitis ◽  
Mindaugas Valincius ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
Hazard Analysis ◽  
Quantitative Risk Assessment ◽  
Study Results ◽  
Risk Aggregation ◽  
Risk Reduction Measures ◽  
The Impact

One of the goals of any oil terminal is to make a business while avoiding hazardous events and harmful effects for both humans and the environment. This can be achieved by creating a safe working place as well as by performing safe and acceptable activities regarding the impact on surrounding objects, including residential and industrial areas. The aim of the hazard analysis of the oil terminal is to assess the risks related to hazardous events or phenomena and to evaluate whether the assessed risks are acceptable. The hazard analysis and assessment of risk are also used for risk reduction while examining and limiting hazardous scenarios that, for instance, involve the loss-of-containment of flammable or combustible material. In this paper, the authors aim to contribute to risk research by providing a comprehensive methodology of risk assessment for oil terminals with case study results and discussion on features of the methodology, risk aggregation, its applicability for risk reduction, and industrial interests. The performed study considered the “Klaipedos Nafta AB” (an operator of the Klaipeda Oil Terminal, Lithuania) case study regarding hazardous materials that might be released from various tanks, devices, and associated pipelines. The performed quantitative risk assessment has enabled the determination of the probability regarding whether releases would ignite and, for instance, cause explosion. In the case study, the estimate of probability, i.e., the frequency, and the possible consequences of the hazardous events were evaluated, and both mitigation and risk reduction measures were also considered.

scholarly journals A Novel Method for Evaluation of Flood Risk Reduction Strategies: Explanation of ICPR FloRiAn GIS-Tool and Its First Application to the Rhine River Basin

Geosciences ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 371 ◽  
Author(s):  
Adrian Schmid-Breton ◽  
Gesa Kutschera ◽  
Ton Botterhuis ◽  
The ICPR Expert Group ‘Flood Risk Analysis’ (EG HIRI)
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
River Basin ◽  
Flood Risk ◽  
Flood Hazard ◽  
Action Plan ◽  
Rhine River ◽  
Culture Heritage ◽  
Flood Risk Reduction ◽  
The Impact

To determine the effects of measures on flood risk, the International Commission for the Protection of the Rhine (ICPR), supported by the engineering consultant HKV has developed a method and a GIS-tool named “ICPR FloRiAn (Flood Risk Analysis)”, which enables the broad-scale assessment of the effectiveness of flood risk management measures on the Rhine, but could be also applied to other rivers. The tool uses flood hazard maps and associated recurrence periods for an overall damage and risk assessment for four receptors: human health, environment, culture heritage, and economic activity. For each receptor, a method is designed to calculate the impact of flooding and the effect of measures. The tool consists of three interacting modules: damage assessment, risk assessment, and measures. Calculations using this tool show that the flood risk reduction target defined in the Action Plan on Floods of the ICPR in 1998 could be achieved with the measures already taken and those planned until 2030. Upon request, the ICPR will provide this tool and the method to other river basin organizations, national authorities, or scientific institutions. This article presents the method and GIS-tool developed by the ICPR as well as first calculation results.

scholarly journals Flood Risk Evaluation in Urban Spaces: The Study Case of Tormes River (Salamanca, Spain)

2018 ◽  
Vol 16 (1) ◽  
pp. 5 ◽  
Author(s):  
Marco Criado ◽  
Antonio Martínez-Graña ◽  
Javier San Román ◽  
Fernando Santos-Francés
Keyword(s):  
Flood Risk ◽  
Risk Evaluation ◽  
Urban Spaces ◽  
Return Periods ◽  
Hazard Maps ◽  
Flood Events ◽  
Hazard Exposure ◽  
Preventive Actions ◽  
Study Case ◽  
Different Levels

The expansion of cities towards flood zones, and the increasingly frequent episodes of torrential rains arising from global warming, mean that the population is becoming more exposed to floods. Due to this, a correct assessment of flood events is of great help in the development of preventive actions, planning and resource management, or interventions. For this reason, in this work we aim to establish guidelines to assess the hazard, exposure, and vulnerability of the population and its properties to flood events, using Hec-Ras for the simulation of the flood and ArcGis and GeoHecRas to treat geographic information and prepare the cartography. The study was focused on the Tormes River in Salamanca (Spain). We studied three return periods with different probabilities of occurrence and intensity, corresponding to 5, 100, and 500 years. The flow corresponding to each episode was calculated, along with the extension, speed, and depth that would be achieved in each case. Then, the probability of occurrence was delimited, as well as the magnitude, allowing us to obtain different hazard maps. In addition, the areas of greatest hazard to people and property were established for each event. Regarding the exposure, the areas and land use, infrastructure, and buildings that would be flooded in each case were identified, quantifying the extension or length of the affected properties at the different levels of hazard in each case. Additionally, the vulnerability of the different buildings and exposed infrastructure was studied. Finally, the flood risk was estimated by combining these three components.

scholarly journals Integrated flood risk assessment of the Arial Khan River under changing climate using IPCC AR5 risk framework

2021 ◽  
Author(s):  
Binata Roy ◽  
Md. Sabbir Mostafa Khan ◽  
A. K. M. Saiful Islam ◽  
Md. Jamal Uddin Khan ◽  
Khaled Mohammed
Keyword(s):  
Risk Assessment ◽  
Flood Risk ◽  
Flood Management ◽  
Hydrologic Model ◽  
Future Climate Change ◽  
Flood Risk Assessment ◽  
High Exposure ◽  
Flood Depth ◽  
Basin Scale ◽  
The Right

Abstract Bangladesh is situated at the confluence of GBM basins, with 90% of the basin area locating outside the country. Future climate change will lead to intense, prolonged, and frequent floods in Bangladesh. An integrated flood risk assessment that transforms risks from transboundary river basins to the local administrative level is necessary. A 1D-2D hydrodynamic model is developed for flood vulnerable Arial Khan River feed by basin-scale hydrologic model for low (RCP2.6) and high (RCP8.5) climate scenarios. An increasing trend in flood depth, duration, and the area is observed from the early (2020s) to the end (2080s) of the century for both scenarios. The difference between both RCPs is minimal from the 2020s to 2050s but becomes very pronounced in the 2080s. The depth-duration area with equal weightage provides better hazard results for the area. Flood risk is assessed using the IPCC AR5 framework incorporating vulnerability and exposure. Some medium-hazard zones fall into high-risk zones due to high exposure and vulnerability to flooding. The areas along the left reach are found more hazard-prone, while the areas on the right side are more risk-prone in the 2080s of RCP8.5. The hazard/risk maps will help policymakers identify priority areas for planning a sustainable flood management strategy.

scholarly journals Process-based flood risk assessment for Germany

2021 ◽  
Author(s):  
Nivedita Sairam ◽  
Fabio Brill ◽  
Tobias Sieg ◽  
Patric Kellermann ◽  
Kai Schröter ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Resolution ◽  
Flood Risk ◽  
Large Scale ◽  
Systems Approach ◽  
Economic Damage ◽  
Flood Risk Assessment ◽  
Continuous Simulation ◽  
Hazard Exposure ◽  
Risk Estimates

<p>Floods affect people worldwide and account for more than USD 100 billion losses on average every year. Hazard, Exposure and Vulnerability are the three components that influence flood risk. Flood Risk Management (FRM) decisions especially, with respect to new flood defense schemes and resilience initiatives are generally taken based on the assessment of impacts for hazard scenarios. Current large-scale studies are comprehensive in terms of sectors covered in impact assessment. However, these studies often deploy generalized data and methods on the model components resulting in coarse risk estimates with low spatial resolution.</p><p>In this study, we use process-based models with 100m resolution on the national scale within a systems approach to develop and simulate a 5000 year flood event catalogue for Germany. The events are then analyzed per economic sector, including residential, commercial and agriculture sectors. The risk chain includes continuous simulation of high-resolution hazard maps, obtained from coupled hydrology and hydraulic models; NUTS3-level exposure asset values further disaggregated to ATKIS land-use data and calibrated object-level vulnerability models that provide high-resolution quantification of economic damage. Spatial dependence of flood events is addressed by the continuous simulation approach. For each model component in the risk assessment (hazard, exposure and vulnerability), uncertainty in data and methods are integrated into the risk predictions. Based on these simulations, we present a sector-wise flood risk assessment for Germany along with the reliability of the risk estimates. This process-based, systemic flood risk assessment is valuable for policy making, adaptation planning and estimating insurance premiums.</p>

scholarly journals Assessing Spatial Flood Risk from Multiple Flood Sources in a Small River Basin: A Method Based on Multivariate Design Rainfall

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1031 ◽  
Author(s):  
Xinyu Jiang ◽  
Lijiao Yang ◽  
Hirokazu Tatano
Keyword(s):  
Risk Assessment ◽  
River Basin ◽  
Flood Risk ◽  
Estimation Procedure ◽  
Flood Risk Assessment ◽  
River Flooding ◽  
Response Characteristics ◽  
Design Rainfall ◽  
Critical Rainfall ◽  
Small River Basin

A key issue in assessing the spatial distribution of flood risk is considering risk information derived from multiple flood sources (river flooding, drainage inundation, etc.) that may affect the risk assessment area. This study proposes a method for assessing spatial flood risk that includes flooding and inundation in small-basin areas through multivariate design rainfall. The concept of critical rainfall duration, determined by the time of concentration of flooding, is used to represent the characteristics of flooding from different sources. A copula method is adopted to capture the correlation of rainfall amounts in different critical rainfall durations to reflect the correlation of potential flooding from multiple flood sources. Rainfalls for different return periods are designed based on the copula multivariate analysis. Using the design rainfalls as input, flood risk is assessed following the rainfall–runoff–inundation–loss estimation procedure. A case study of the Otsu River Basin, Osaka Prefecture, Japan, was conducted to demonstrate the feasibility and advantages of this method. Compared to conventional rainfall design, this method considers the response characteristics of multiple flood sources, and solves the problem of flood risk assessment from multiple flood sources. It can be applied to generate a precise flood risk assessment to support integrated flood risk management.

scholarly journals Event generation for probabilistic flood risk modelling: multi-site peak flow dependence model vs. weather-generator-based approach

2020 ◽  
Vol 20 (6) ◽  
pp. 1689-1703 ◽  
Author(s):  
Benjamin Winter ◽  
Klaus Schneeberger ◽  
Kristian Förster ◽  
Sergiy Vorogushyn
Keyword(s):  
Risk Assessment ◽  
Return Period ◽  
Flood Risk ◽  
Flood Damage ◽  
Weather Generator ◽  
Process Models ◽  
Flood Events ◽  
Entire Study ◽  
Advantages And Disadvantages ◽  
Peak Discharges

Abstract. Flood risk assessment is an important prerequisite for risk management decisions. To estimate the risk, i.e. the probability of damage, flood damage needs to be either systematically recorded over a long period or modelled for a series of synthetically generated flood events. Since damage records are typically rare, time series of plausible, spatially coherent event precipitation or peak discharges need to be generated to drive the chain of process models. In the present study, synthetic flood events are generated by two different approaches to modelling flood risk in a meso-scale alpine study area (Vorarlberg, Austria). The first approach is based on the semi-conditional multi-variate dependence model applied to discharge series. The second approach relies on the continuous hydrological modelling of synthetic meteorological fields generated by a multi-site weather generator and using an hourly disaggregation scheme. The results of the two approaches are compared in terms of simulated spatial patterns of peak discharges and overall flood risk estimates. It could be demonstrated that both methods are valid approaches for risk assessment with specific advantages and disadvantages. Both methods are superior to the traditional assumption of a uniform return period, where risk is computed by assuming a homogeneous return period (e.g. 100-year flood) across the entire study area.

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