Flood Damage Functions Research Articles

Flood Damage Function Model for Residential area in Kuantan: A Preliminary Study

Flood damage estimation is an essential element in the assessment of flood risk. However, the assessment of flood damage in developing countries is challenging due to the scarcity of historical data. An attempt has been made to assess the flood damages of 2013 Kuantan flood and to develop a flood damage function model based on the socio-economic and property characteristics of the study area. A field survey was conducted to gather damage data and information regarding the flood event using face to face interview technique. Age, household income, educational background, occupation and the distance from river have been identified as the most significant variables that influence the residential flood damages. A damage model to aid in the estimation of the structural and content damage have been developed. The preliminary results can be used in the future flood damage assessment works, especially in the development of flood damage function curve.

Application of geographic weighted regression to establish flood-damage functions reflecting spatial variation

Flood damage functions are necessary to ensure comprehensive flood-risk management. This study attempts to establish a residential flood-damage function through interviewing the residents living in the region where flood disasters occur frequently. Keelung River basin, near Taipei Metropolitan in Taiwan was selected as study area. Flood damages are related to the flood depths, which are the most commonly considered factor in previously published work. Ordinary least squares (OLS) regression was used to construct the flood-damage function at the beginning. Analytical results indicate that flood depth is the significant variable, but the spatial pattern of the residuals shows that residuals exhibit spatial autocorrelation. The Geographically Weighted Regression (GWR) Model was then applied to modify the traditional regression model, which cannot capture spatial variations, and to reduce the problem of spatial autocorrelation. The R-square value was found to increase from 0.15 to 0.24, and the spatial autocorrelation in the residuals was no longer evident. A modified OLS model with a dummy variable to capture the spatial autocorrelation pattern was also proposed for future applications. In conclusion, the residential flood damage is determined by flood depth and zone, and the GWR model not only captures the spatial variations of the affecting factors, but also helps to discover the independent variable to modify the traditional regression model.

FLOOD RISK ASSESSMENT: A REVIEW OF FLOOD DAMAGE ESTIMATION MODEL FOR MALAYSIA

Flood damage assessment is important in flood risk management for the assessment of flood vulnerability, development of flood risk map and flood management financial appraisal. In Malaysia, there is a lack of studies on flood damages estimation. In addition, the needed data for the assessment of flood damages is scarce. This review identified the approaches and problems in flood damage assessment. For Malaysia, the combination of four elements namely; flood characteristics (flood depth and flood duration), characteristic of exposed elements, value of exposed element and flood damage function curve are recommended. The scarcity of data for developing flood damage curve could partly be overcome by applying synthetic method to generate additional data from the existing flood damage data.

Establishment of flood damage function models: A case study in the Bago River Basin, Myanmar

This paper derives flood damage function models based on the relationships between flood inundation parameters and damage-aggravating factors for two land use categories: residential and agricultural. This case study considers the Bago River Basin in Myanmar, which is frequently damaged by flooding. A survey was conducted to determine the economic damage to affected populations and properties during a large flood in 2011. House damage, in-house damage, and income loss function models were established for residential areas, along with an agricultural damage function model. Flood water height, floor height from the ground, occurrence of landslide erosion and types of building materials could aggravate house damage, whereas in-house damage is exacerbated by flood water height above plinth level and types of house's plinth level. Income loss scales with flood duration, job category and household level. Flood water height, flood duration and the growth stage of paddies worsen agricultural damage. Knowing the relationship between flooding and its damaging factors, these models can be easily applied to a flood loss estimation model in further research.

Development of Multivariate Flood Damage Function for Flood Damage Assessment in Gunsan City, Korea

한국의 경제성장과 재해방재기술 향상에도 불구하고 홍수와 같은 자연재해는 여전히 국민들을 위협하고 있으며 특히, 태풍에 의해 발생한 홍수피해는 막대한 재산과 인명피해의 원인이 되어왔다. 홍수에 의한 피해액을 추정하는 것은 홍수대책마련과 홍수피해를 저감하는데 매우 중요하다. 이와 관련하여 피해 및 손실을 평가 및 분석하고 재해 위험 관리 계획에 따라 해당...

PGP-MIP model for evaluating non-damaging flows in a river system

A new pre-emptive goal programming model formulation accounting sequential and gradual changes in flow depths/discharge at a river section is presented. The model is used for evaluating conditions for maximum safe drainage for a river basin in India. The model is applied to Barak river system in India for determining upstream flow sets satisfying downstream flood flow criterion. To account for nonlinearity in flood damage function downstream flow rates are partitioned into a number of flow zones. Logical constraint equations are used to ensure gradual and sequential movement of water in the flow zones. The model is used to determine safe drainage capacity for giving higher priority to basin drainage and downstream flood safety respectively. As determined by the river system properties, the study results reveal the upstream flow combinations satisfying downstream safe flow criterion; depicts nonlinear variations of the sub basins flow with the peak flow rate at the main channel. The study demonstrates applicability of the PGP-MIP model with results that are useful to the study river system.

Establishing flood damage functions for agricultural crops using estimated inundation depth and flood disaster statistics in data-scarce regions

Establishing flood damage functions for agricultural crops using estimated inundation depth and flood disaster statistics in data-scarce regions

PGP-MIP model for evaluating non-damaging flows in a river system

A new pre-emptive goal programming model formulation accounting sequential and gradual changes in flow depths/discharge at a river section is presented. The model is used for evaluating conditions for maximum safe drainage for a river basin in India. The model is applied to Barak river system in India for determining upstream flow sets satisfying downstream flood flow criterion. To account for nonlinearity in flood damage function downstream flow rates are partitioned into a number of flow zones. Logical constraint equations are used to ensure gradual and sequential movement of water in the flow zones. The model is used to determine safe drainage capacity for giving higher priority to basin drainage and downstream flood safety respectively. As determined by the river system properties, the study results reveal the upstream flow combinations satisfying downstream safe flow criterion; depicts nonlinear variations of the sub basins flow with the peak flow rate at the main channel. The study demonstrates applicability of the PGP-MIP model with results that are useful to the study river system.

Uncertainty in flood damage estimates and its potential effect on investment decisions

Abstract. This paper addresses the large differences that are found between damage estimates of different flood damage models. It explains how implicit assumptions in flood damage functions and maximum damages can have large effects on flood damage estimates. This explanation is then used to quantify the uncertainty in the damage estimates with a Monte Carlo analysis. The Monte Carlo analysis uses a damage function library with 272 functions from seven different flood damage models. The paper shows that the resulting uncertainties in estimated damages are in the order of magnitude of a factor of 2 to 5. The uncertainty is typically larger for flood events with small water depths and for smaller flood events. The implications of the uncertainty in damage estimates for flood risk management are illustrated by a case study in which the economic optimal investment strategy for a dike segment in the Netherlands is determined. The case study shows that the uncertainty in flood damage estimates can lead to significant over- or under-investments.

Application of Harmony Search Algorithm to Reservoir Operation Optimization

In this study, a meta-heuristic technique called harmony search (HS) algorithm is developed for reservoir operation optimization with respect to flood control. The HS algorithm is used to minimize the water supply deficit and flood damages downstream of a reservoir. The GIS database is used to determine the flood damage functions. The efficacy of HS algorithm is evaluated in comparison with other techniques by using a benchmark problem for a single reservoir operation optimization problem. HS showed promising results in terms of speed of convergence to an optimal objective function value compared with other techniques such as honey-bee mating optimization (HBMO) and a global optimization model (LINGO 8.0 NLP solver). The HS algorithm is then applied to the Narmab reservoir, north of Iran, as a case study. Narmab reservoir serves multiple purposes including irrigation, flood control, and drinking water requirements. The developed model is applied for monthly operation. The results show that the HS algorithm can be effectively used for operation of reservoir for flood management.

A Review of Flood Risk Analysis in Nigeria

Nigeria has witnessed diverse flood events in the past years and due to the high level of vulnerability and lack of coping capacity of the people, with the fast occurrence of extreme events resulting from climate change, many lives and properties are at risk of its impacts. This paper reviews the recent past and present efforts in assessing the flood impacts in Nigeria. We concentrate this study on the recent works (methods and results) in assessing flood impacts in the country under basic components of flood risk analysis: The hazards mapping and modeling, exposure and vulnerability assessment, with the aim of suggesting possible urgent needs and further development. Based on our review, we conclude that, there is need to explore more effectively the use of state of the art flood models, which integrates all hydrological processes for more accurate prediction and mapping of flood and its associated risks. Also, as one of the steps to plan for adaptation and mitigation of future flood risk and climate change, there is a serious need of detailed research in the development of regional or national flood damage functions for pre-disaster flood damage estimation. The study also suggests further study on the environmental and health impact of flood in the country.

Estimation of flood damage functions for river basin planning: a case study in Bangladesh

Located at the low-lying deltaic floodplain of Ganges–Brahmaputra–Meghna river basin, Bangladesh suffers damages from flooding with regularity. From the perspective of long-term planning and management, a reliable flood damage function is a critical component in the estimation of flood-induced economic loss. Such functions are, however, notoriously difficult to develop. This study utilizes in-stream water level and flood-affected area (FAA) data from Flood Forecasting and Warning Center and Bangladesh Water Development Board to evaluate the best form and data input characteristics of flood damage functions for Bangladesh. The performance of various function configurations (geographic data, water level data, and function form) was tested. The Nash–Sutcliffe efficiency and residual error analysis results suggest that, in general, the logistic function performs better than the other two function forms, and the maximum of daily-maximal water level is the best suited to estimate (FAA). As expected, when information is available from all basins (the Ganges, the Brahmaputra, and the Meghna), the resulting flood damage functions provide the most accurate estimations of FAA. Furthermore, the comparison between single- and multivariable flood damage functions does not demonstrate a clear advantage of using multivariate function in our study area. When flood damage functions with finer spatial and temporal resolution can be constructed using remote sensing technology or hydrodynamic modeling, the intra-year and district-level changes to FAA can be evaluated. These findings provide a better flood management plan for Bangladesh and have potential to be generalized to other similarly flood-affected nations.

Fundamental Analysis for Flood Risk Management in the Selected River Basins of Southeast Asia

Flood features were analyzed and risk knowledge was examined in studies in selected river basins of Southeast Asia. Rainfall runoff features were analyzed in Indonesia’s Solo river basin and in the Philippines’ Pampanga and Cagayan river basins using ground-observed and satellite-based (GSMaP) rainfall data. Flood damage was assessed for risk management by considering physical damage to agricultural and household in the Cambodian flood plain of the Lower Mekong Basin and in the Philippines’s Pampanga river basin. A comparison of simulated and observed runoff hydrographs showed that the accuracy of GSMaP rainfall in the Solo and Cagayan river basins in studied flood events was lower than in the Pampanga river basin case. In the Pampanga and Cagayan river basins, the density of rainfall station networks was below the WMO recommendation, and GSMaP rainfall data would be more effective in getting supplementary information for existing flood-forecasting systems for these river basins. Physical damage to households including residential assets and agricultural damage were estimated quantitatively based on flood features. The estimated value of agricultural and house damage was fairly consistent with reported values. Reliable flood damage data are important for developing flood damage functions and for confirming such estimation. Uncertainties associated with input data, model parameters, and damage information strongly influence the damage estimated. These uncertainties must be considered carefully in flood risk assessment models.

The impacts of climate change on river flood risk at the global scale

This paper presents an assessment of the implications of climate change for global river flood risk. It is based on the estimation of flood frequency relationships at a grid resolution of 0.5 × 0.5°, using a global hydrological model with climate scenarios derived from 21 climate models, together with projections of future population. Four indicators of the flood hazard are calculated; change in the magnitude and return period of flood peaks, flood-prone population and cropland exposed to substantial change in flood frequency, and a generalised measure of regional flood risk based on combining frequency curves with generic flood damage functions. Under one climate model, emissions and socioeconomic scenario (HadCM3 and SRES A1b), in 2050 the current 100-year flood would occur at least twice as frequently across 40 % of the globe, approximately 450 million flood-prone people and 430 thousand km2 of flood-prone cropland would be exposed to a doubling of flood frequency, and global flood risk would increase by approximately 187 % over the risk in 2050 in the absence of climate change. There is strong regional variability (most adverse impacts would be in Asia), and considerable variability between climate models. In 2050, the range in increased exposure across 21 climate models under SRES A1b is 31–450 million people and 59 to 430 thousand km2 of cropland, and the change in risk varies between −9 and +376 %. The paper presents impacts by region, and also presents relationships between change in global mean surface temperature and impacts on the global flood hazard. There are a number of caveats with the analysis; it is based on one global hydrological model only, the climate scenarios are constructed using pattern-scaling, and the precise impacts are sensitive to some of the assumptions in the definition and application.

Estimation of an absolute flood damage curve based on an Austrian case study under a dam breach scenario

Abstract. To date, in Austria no empirical assessment of absolute damage curves has been realized on the basis of detailed information on flooded buildings due to a dam breach, presumably because of the lack of data. This paper tries to fill this gap by estimating an absolute flood-damage curve, based on data of a recent flood event in Austria in 2006. First, a concise analysis of the case study area is conducted, i.e., the maximum damage potential is identified by using raster-based GIS. Thereafter, previous literature findings on existing flood-damage functions are considered in order to determine a volume-water damage function that can be used for further flood damage assessment. Finally, the flood damage function is cross validated and applied in prediction of damage potential in the study area. For future development of the estimated flood damage curve, and to aid more general use, we propose verification against field data on damage caused by natural waves in rivers.

Proving the ecosystem value through hydrological modelling

Ecosystems provide valuable functions. Also natural floodplains and river structures offer different types of ecosystem functions such as habitat function, recreational area and natural detention. From an economic stand point the loss (or rehabilitation) of these natural systems and their provided natural services can be valued as a damage (or benefit). Consequently these natural goods and services must be economically valued in project assessments e.g. cost-benefit-analysis or cost comparison. Especially in smaller catchments and river systems exists significant evidence that natural flood detention reduces flood risk and contributes to flood protection. Several research projects evaluated the mitigating effect of land use, river training and the loss of natural flood plains on development, peak and volume of floods. The presented project analysis the hypothesis that ignoring natural detention and hydrological ecosystem services could result in economically inefficient solutions for flood protection and mitigation. In test areas, subcatchments of the Danube in Germany, a combination of hydrological and hydrodynamic models with economic evaluation techniques was applied. Different forms of land use, river structure and flood protection measures were assed and compared from a hydrological and economic point of view. A hydrodynamic model was used to simulate flows to assess the extent of flood affected areas and damages to buildings and infrastructure as well as to investigate the impacts of levees and river structure on a local scale. These model results provided the basis for an economic assessment. Different economic valuation techniques, such as flood damage functions, cost comparison method and substation-approach were used to compare the outcomes of different hydrological scenarios from an economic point of view and value the ecosystem service. The results give significant evidence that natural detention must be evaluated as part of flood mitigation projects. In addition can be stated that the loss of detention due to land use and dikes can be called an externality and results in economic inefficiencies.

Standard residential flood damage functions for South African conditions

Disaster risk management is an integral part of a scientific approach to disaster management. It refers to integrated, multi-sectoral, multi-disciplinary, organizational and operational planning processes and skills to mitigate disasters. Application of the approach necessitates disaster risk analysis, requiring flood damage functions in the case of floods. A flood damage function can be described mathematically, tabularly or graphically and refers to the relationship between flood characteristics like depth and/or speed of floodwater and flood damage to a specific land use type. Research conducted at the University of the Free State indicated the value of standard residential flood damage functions and the necessity for periodic updating to secure contemporary relevance. This article focuses on updating of the latter. The article starts with an introduction to put the development, use and maintenance of standard residential flood damage functions in context with regard to the latest views on disaster risk management, risk assessment, disaster management legislation in South Africa and a computer model TEWA, in which the flood damage functions are used. Aspects that can affect flood damage are briefly discussed, followed by sections on the development and upgrading of structural flood damage functions for formal housing as well as functions for determining damage to housing contents. The development of residential flood damage functions that can be applied nationally forms the main part of the paper and is followed by a brief summary statement.

'N VLOEDSKADESIMULASIEMODEL VIR DIE HERBEPLANNING/—STRUKTURERING VAN 'N VLOEDVLAKTE / A FLOOD DAMAGE SIMULATION MODEL FOR THE REPLANNING/RESCHEDULATION OF A FLOOD PLAN

In South Africa a start was made, during research into the effects of floods during the seventies to developing a set of flood damage functions based on actual floods. Repired follow-up research was not continued during the eighties. For various reasons flood damage, based on actual floods, is underestimated and/or overestimated; a second method for estimating potential flood damages, namely the ex ante approach, was followed to compile loss functions based on potential floods. With relationships between the money value of direct flood damage to a damaged item (damage when an item was in physical contact with flood waters) and one or more characteristics of the flood, eg. depth of flood waters, duration of flooding, and the momentum flux of the flood waters, the money value of the direct damage that will be caused by floods of different sizes can be estimated before floods actually occur. This forms an integral part of flood damage simulation models. A geographic information system (GIS) approach was foll...

The value of coastal wetlands for protection of property against hurricane wind damage

The paper has attempted to place a value on wetlands for their role in reducing wind damage to property because of diminished storm intensities. The study estimated a storm wind damage function for the Louisiana gulf coast, where inland distance of a location and wetlands traversed by a hurricane were among the independent was made of the increase in expected wind damage to property from the loss of intervening wetlands. The discounted value of the loss of a one mile strip of wetlands along Louisiana's gulf coast was estimated to be between $1.1 million and $3.7 million in 1980 dollars, using discount rates of 8% and 3%, respectively. Although it may not be too meaningful to place this on a per acre basis, this increased cost of property damage amounted to between $7 and $23 per acre. In order to place this in perspective, the market value of Louisiana wetlands is under $200 per acre. This market value is derived primarily from the mineral and hunting rights accompanying the surface area. This hurricane protection value is only one of many pure or quasipublic goods produced by wetlands. In order to make decisions regarding costly projects designed to retard wetlands erosion, such as revegetation or sediment transfers; or to consider wetlands destroying developments, such as pipeline canal construction, the value of these public goods must be estimated. The current study adds to our knowledge of these values. The next stage in this line of research is to evaluate the benefits that wetlands provide by reducing storm tidal surge. Flood damages to low-lying coastal areas are considerably greater than wind damage, and wetlands areas may be more useful for flood protection to these areas than for reducing storm intensities. Unfortunately, establishing a flood damage function similar to the wind damage function used in this study is difficult since it must consider unique hydrologic features of affected coastal areas.

Bayesian inference and decision making for extreme hydrologic events

Hydrologic decision making usually occurs in an uncertain world and should combine inferences about uncertain outcomes with the decision makers’ preferences toward these outcomes. The decisions associated with flood protection are considered in detail where there exists uncertainty in the frequency of future flood discharges. Procedures are developed for analyzing and accounting for both statistical uncertainty of competing flood frequency models and statistical parameter uncertainty for the individual models. Inferences about flood frequency are combined with a decision model for which the decision rule is the maximization of expected monetary benefits. A case study to determine the optimal size of local flood protection by using prior information from a regional regression model, historical data, and realistic flood cost and damage functions is presented.