Defining and Analyzing the Frequency and Severity of Flood Events to 
Improve Risk Management from a Reinsurance Standpoint

Morrill, Elliott P.; Becker, Joseph F.

doi:10.5194/hess-2017-167

Cited by 5 publications

(9 citation statements)

References 3 publications

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“…Previous studies tackled the problem of the identification of flood events affecting wide areas (Uhlemann et al 2010;Gvoždíková and Müller 2017;Morrill and Becker 2017;Hundecha et al 2017). Leaving aside specific differences, these approaches comprise a preliminary POT selection, which identifies potential flood peaks over a set of locations, and a subsequent clustering procedure that gathers together sites showing POT exceedances within a given time window.…”

Section: Discussionmentioning

confidence: 99%

“…However, some of these peaks may be not extreme. Therefore, actual flood events are usually selected by using some criterion such as a peak-overthreshold approach (POT;Uhlemann et al 2010;Gvoždíková and Müller 2017;Morrill and Becker 2017). The threshold can be chosen according to the aim of the study, but common values are the at-site discharge values exceeded with annual probability of 0.5 or 0.1 (i.e., the 2-and 10-year RP levels, Q 2 and Q 10 , respectively), where the former option provides a good approximation of the bankfull discharge, while the latter is commonly used to delineate the first class of flood-prone areas in risk mapping as well as the areas within which assets are usually considered as not insurable (Kron 2005;Uhlemann et al 2010, and references therein).…”

Section: Identification Of Historical Eventsmentioning

confidence: 99%

“…As further discussed in Sect. 4, Uhlemann et al (2010), Gvoždíková and Müller (2017), and Morrill and Becker (2017) proposed alternative methods, based on similar principles, devised to identify flood events at a basin scale for flood risk management and reinsurance purposes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Flood propagation and duration in large river basins: a data-driven analysis for reinsurance purposes

et al. 2018

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Duration is a key characteristic of floods influencing the design of protection infrastructures for prevention, deployment of rescue resources during the emergency, and repartition of damage costs in the aftermath. The latter financial aspect mainly relies on the insurance industry and allows the transfer of damage costs from the public sector to the private capital market. In this context, the cost of catastrophes affecting a large amount of insured properties is partly or totally transferred from insurance companies to reinsurance companies by contracts that define the portion of transferred costs according to the temporal extent of the flood events synthesized in the so-called hours clause. However, hours clauses imply standard flood event durations, such as 168 h (1 week), regardless of the hydrological properties characterizing different areas. In this study, we firstly perform a synoptic-scale exploratory analysis to investigate the duration and magnitude of large flood events that occurred around the world and in Europe between 1985 and 2016, and then we present a data-driven procedure devised to compute flood duration by tracking flood peaks along a river network. The exploratory analysis highlights the link of flood duration and magnitude with flood generation mechanism, thus allowing the identification of regions that are more or less prone to long-lasting events exceeding the standard hours clauses. The flood tracking procedure is applied to seven of the largest river basins in Central and Eastern Europe (Danube, Rhine, Elbe, Weser, Rhone, Loire, and Garonne). It correctly identifies major flood events and enables the definition of the probability distribution of the flood propagation time and its sampling uncertainty. Overall, we provide information and Disclaimer: Any views and opinions expressed in this article are those of the authors and do not necessarily reflect the scientific view or position of AIR Worldwide.

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Section: Discussionmentioning

confidence: 99%

Section: Identification Of Historical Eventsmentioning

confidence: 99%

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Flood propagation and duration in large river basins: a data-driven analysis for reinsurance purposes

et al. 2018

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“…Floods are the most devastating hazards that have potential to cause damage to natural environment, displacement of people, destruction of infrastructure: buildings, roads, railways, bridges and power transmission lines [1]- [6]. The severity of flood impacts however, depends on a number of factors such as geographic location, topography, soil types of the area, increased human settlements and economic assets in floodplains, and reduction of the natural water retention by increased land use change [7] [8].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Socio-Economic Impacts of the December 2011 Flood Event in Dar es Salaam, Tanzania

Anande¹,

Luhunga²

2019

ACS

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Floods are the most devastating hazards that have significant adverse impacts on people and their livelihoods. Their impacts can be reduced by investing on: 1) improving the forecasting skills of extreme and heavy rainfall events, 2) development of Impacts Based Flood Early Warning System (IBFEWS) and 3) effective communication of impacts from anticipated extreme or heavy rainfall event. The development of IBFEWS however, requires a complete understanding of factors that relates to the formation of extreme or heavy rainfall events and their associated socioeconomic impacts. This information is crucial in the development of Impacts Based Flood Forecasting Models (IBFFMs). In this study, we assess the socioeconomic impacts of the December 2011 flood event in Dar es Salaam as the preliminary stage in the development of IBFFMs for the City of Dar es Salaam. Data from household survey collected using systematic random sampling techniques and structured questionnaires are used. The survey was conducted to acquire respondent's views on the causes of floods impacts, adaptive capacity to extreme or heavy rainfall events and adaptation options to minimize flood impact. It is found that the main causes of floods were river overflow due to heavy rainfall and blocked drainage system. Poor infrastructure such as drainage and sewage systems, and ocean surge were identified to be the causes of observed impacts of the December 2011 flood event in Dar es Salaam. Death cases analysis showed that 43 people were reported dead. The flood event damaged properties worth of 7.5 million Tanzania shillings. Furthermore, the Tanzania Government spent a total amount of 1.83 billion Tanzanian shillings to rescue and relocate vulnerable communities that lived-in low-lying areas of Jagwani to high ground areas of Mabwepande in Kinondoni district.

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“…Since floods are expected to increase due to climatic changes (Asadieh and Krakauer, 2015;Arnell and Gosling, 2016;Beniston et al, 2007;Bouwer, 2013;Fischer and Knutti, 2016;Millán, 2014;Pfahl et al, 2017;Rajczak et al, 2013;Scherrer et al 2016), flood risk analyses and the management of extreme events will become even more relevant (Smolka, 2006;Yuan et al, 2017). Hence, insurance companies as well as governmental institutions are increasingly interested in quantifying flood risks, and especially in estimating the impacts of probable maximum floods leading to high 5 cumulative losses (Burke et al, 2016;Morrill and Becker, 2017) or the destruction of critical infrastructure (Hasan and Foliente, 2015;Mechler et al, 2010;Michaelides, 2014). …”

Section: Introductionmentioning

confidence: 99%

Effects of variability in probable maximum precipitation patterns on flood losses

Zischg¹,

Felder²,

Weingartner³

et al. 2018

Preprint

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Abstract. The assessment of the impacts of extreme floods is important for dealing with residual risk, particularly for critical infrastructure management and for insurance purposes. Thus, modelling of the probable maximum flood (PMF) from probable maximum precipitation (PMP) by coupling hydrologic and hydraulic models has gained interest in recent years.Herein, we examine whether variability in precipitation patterns exceeds or is below other uncertainties in flood loss 15 estimation and if the flood losses within a river basin are related to the probable maximum discharge at the basin outlet. We developed a model experiment with an ensemble of probable maximum precipitation scenarios created by Monte-Carlo simulations. For each rainfall pattern, we computed the flood losses with a model chain and benchmarked the effects of variability in rainfall distribution with other model uncertainties. The results show that flood losses vary considerably within the river basin and depend on the timing and superimposition of the flood peaks from the basin's sub-catchments. In addition 20 to the flood hazard component, the other components of flood risk, exposure and vulnerability, contribute remarkably to the overall variability. This leads to the conclusion that the estimation of the probable maximum expectable flood losses in a river basin should not be based exclusively on the PMF. Consequently, the basin-specific sensitivities to different precipitation patterns and the spatial organisation of the settlements within the river basin need to be considered in the analyses of probable maximum flood losses. 25

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Defining and Analyzing the Frequency and Severity of Flood Events to Improve Risk Management from a Reinsurance Standpoint

Cited by 5 publications

References 3 publications

Flood propagation and duration in large river basins: a data-driven analysis for reinsurance purposes

Flood propagation and duration in large river basins: a data-driven analysis for reinsurance purposes

Assessment of Socio-Economic Impacts of the December 2011 Flood Event in Dar es Salaam, Tanzania

Effects of variability in probable maximum precipitation patterns on flood losses

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