Pluvial flood catastrophe modelling: a trans-disciplinary approach.

2020 ◽  
Author(s):  
Konstantinos Karagiorgos ◽  
Daniel Knos ◽  
Jan Haas ◽  
Sven Halldin ◽  
Barbara Blumenthal ◽  
...  
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Urban Areas ◽  
Insurance Industry ◽  
Integrated Approach ◽  
Effective Prevention ◽  
The Public ◽  
Modelling Framework ◽  
Catastrophe Modelling ◽  
The Impact

<p>Pluvial floods are one of the most significant natural hazards in Europe causing severe damage to urban areas. Following the projected increase in extreme precipitation and the ongoing urbanization, these events play an important role in the ongoing flood risk management discussion and provoke serious risk to the public as well as to the insurance sector. However, this type of flood, remains a poorly documented phenomenon. To address this gap, Swedish Pluvial Modelling Analysis and Safety Handling (SPLASH) project aims to develop new methods and types of data that improve the possibility to value flood risk in Swedish municipalities by collaboration between different disciplines.</p><p>SPLASH project allows to investigating the impact of heavy precipitation along the entire risk modelling chain, ultimate needed for effective prevention. This study presents a pluvial flood catastrophe modelling framework to identify and assess hazard, exposure and vulnerability in urban context. An integrated approach is adopted by incorporating ‘rainfall-damage’ patterns, flood inundation modelling, vulnerability tools and risk management. The project is developed in the ‘OASIS Loss Modelling Framework’ platform, jointly with end-users from the public sector and the insurance industry.</p><p>The Swedish case study indicates that the framework presented can be considered as an important decision making tool, by establishing an area for collaboration between academia; insurance businesses and rescue services, to reduce long-term disaster risk in Sweden.</p>

What value do mangroves have in reducing the cost of storm surges?

2020 ◽  
Author(s):  
Christopher Thomas ◽  
Siddharth Narayan ◽  
Joss Matthewman ◽  
Christine Shepard ◽  
Laura Geselbracht ◽  
...  
Keyword(s):  
Storm Surge ◽  
Insurance Industry ◽  
Economic Value ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Economic Losses ◽  
Modelling Framework ◽  
Catastrophe Modelling ◽  
The Cost ◽  
The Impact

<p>With coastlines becoming increasingly urbanised worldwide, the economic risk posed by storm surges to coastal communities has never been greater. Given the financial and ecological costs of manmade coastal defences, the past few years have seen growing interest in the effectiveness of natural coastal “defences” in reducing the risk of flooding to coastal properties, but estimating their actual economic value in reducing storm surge risk remains a challenging subject.</p><p>In this study, we estimate the value of mangroves in reducing annual losses to property from storm surges along a large stretch of coastline in Florida (USA), by employing a catastrophe modelling approach widely used in the insurance industry. We use a hydrodynamic coastal flood model coupled to a property loss model and a large property exposure dataset to estimate annual economic losses from hurricane-driven storm surges in Collier County, a hurricane-prone part of Florida. We then estimate the impact that removing mangroves in the region would have on average annual losses (AAL) caused by coastal flooding. We find that mangroves reduce AAL to properties behind them by over 25%, and that these benefits are distributed very heterogeneously along the coastline. Mangrove presence can also act to enhance the storm surge risk in areas where development has occurred seaward of mangroves.</p><p>In addition to looking at annual losses, we also focus on the storm surge caused by a specific severe event in Florida, based on Hurricane Irma (2017), and we estimate that existing mangroves reduced economic property damage by hundreds of millions of USD, and reduced coastal flooding for hundreds of thousands of people.</p><p>Together these studies aim to financially quantify some of the risk reduction services provided by natural defences in terms of reducing the cost of coastal flooding, and show that these services can be included in a catastrophe modelling framework commonly used in the insurance industry.</p>

scholarly journals Flood Risk Assessment of the Wadi Nu’man Basin, Mecca, Saudi Arabia (During the Period, 1988–2019) Based on the Integration of Geomatics and Hydraulic Modeling: A Case Study

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1887 ◽  
Author(s):  
Ashraf Abdelkarim ◽  
Ahmed F.D. Gaber
Keyword(s):  
Flood Risk ◽  
Urban Areas ◽  
Integrated Approach ◽  
Hydraulic Modeling ◽  
Likelihood Method ◽  
Risk Matrix ◽  
Protection Measures ◽  
Erdas Imagine ◽  
Water Volumes ◽  
The Impact

This study aims to assess the impact of flash floods in the Wadi Nu’man basin on urban areas, east of Mecca, which are subjected to frequent floods, during the period from 1988–2019. By producing and analyzing the maps of the regions, an integrated approach to geomatics and hydraulic modelling is employed. The following maps are used: Flood-prone urbanity from 1988–2019, a flood risk map of Wadi Nu’man based on a risk matrix map, and a map of the proposed protection measures and alternatives in the study area. In order to achieve these goals, changes in the land use in the Wadi Nu’man basin were monitored by analyzing successive satellite images, taken by the US satellite, Landsat, in 1988, 1998, 2013, and 2019. Using a supervised classification, with the maximum likelihood method of ERDAS IMAGINE 2016, GIS was used in the production and analysis of soil maps, and geological and hydrological groups of drainage basins, as well as the hydrological model (HEC-HMS), were applied in calculating the hydrograph curve of the Wadi Nu’man basin. The flood water volumes and flow rates were estimated based on the SCS unit hydrograph, and the rain depth was analyzed and estimated for different periods. The hydraulic modeling program (HEC-RAS) was employed, when developing a two-dimensional model to calculate the speed, depth, and spread of the flood, in order to apply the risk matrix method. The recommendations based on this study give priority to the implementation of a flood prevention plan and the protection of infrastructure by maintaining the existing flood drainage facilities and establishing new drainage facilities to protect lives, property, and infrastructure.

Cloudburst catastrophe modelling: Case study – Jönköping municipality, Sweden 

2021 ◽  
Author(s):  
Konstantinos Karagiorgos ◽  
Sven Halldin ◽  
Jan Haas ◽  
Daniel Knos ◽  
Barbara Blumenthal ◽  
...  
Keyword(s):  
Insurance Industry ◽  
Claim Data ◽  
The Public ◽  
Catastrophe Model ◽  
Modelling Framework ◽  
Catastrophe Modelling ◽  
Insurance Claim Data ◽  
Loss Modelling

<p>In Europe, flash floods are one of the most significant natural hazards, causing serious risk to life and destruction of buildings and infrastructure. The intense rain causing those floods has a few different names, however, with very similar meaning. The term chosen in this study, ‘cloudburst’, was introduced by Woolley (1946) as “…a torrential downpour of rain which by its spottiness and relatively high intensity suggests the bursting and discharge of the whole cloud at once”. While these events play an important role in the ongoing flood risk management discussion, they are under-represented among flood models.</p><p>The main aim of this study is to demonstrate an approach by showing how methods and techniques can be integrated together to construct a catastrophe model for flash flooding of Jönköping municipality in Sweden. The model is developed in the framework of the ‘Oasis Loss Modelling Framework’ platform, jointly with end-users from the public sector and the insurance industry. Calibration and validation of the model were conducted by comparisons against three historical cloudburst events and corresponding insurance-claim data.</p><p>The analysis has shown that it is possible to get acceptable results from a cloudburst catastrophe model using only rainfall data, and not surface-water level as driving variable. The approach presented opens up for such loss modelling in places where complex hydraulic modelling cannot be done because of lacking data or skill of responsible staff. The Swedish case study indicates that the framework presented can be considered as an important decision making tool, by establishing an area for collaboration between academia; insurance businesses; and local authorities, to reduce long-term disaster risk in Sweden.</p><p> </p><p>Woolley, Ralf R., "Cloudburst Floods in Utah 1850-1938" (1946). Elusive Documents. Paper 55.</p>

scholarly journals The value of integrating information from multiple hazards for flood risk management

2013 ◽  
Vol 1 (4) ◽  
pp. 3305-3371
Author(s):  
J. T. Castillo-Rodríguez ◽  
I. Escuder-Bueno ◽  
L. Altarejos-García ◽  
A. Serrano-Lombillo
Keyword(s):  
Risk Management ◽  
Risk Analysis ◽  
Flood Risk ◽  
Urban Areas ◽  
Integrated Approach ◽  
Flood Risk Management ◽  
Dam Failure ◽  
Flood Hazards ◽  
River Flooding ◽  
Flood Risk Analysis

Abstract. This article presents a methodology for estimating flood risk in urban areas integrating pluvial flooding, river flooding and failure of both small and large dams. The first part includes a review of basic concepts and existing methods on flood risk analysis, evaluation and management. Traditionally, flood risk analyses have focused on specific site studies and qualitative or semi-quantitative approaches. However, in this context, a general methodology to perform a quantitative flood risk analysis including different flood hazards was still required. The second part describes the proposed methodology, which presents an integrated approach – combining pluvial, river flooding and dam failure, as applied to a case study: a urban area located downstream a dam under construction. Such methodology represents an upgrade of the methodological piece developed within the SUFRI project. This article shows how outcomes from flood risk analysis provide better and more complete information to inform authorities, local entities and the stakeholders involved on decision-making with regard to flood risk management.

scholarly journals Large-scale application of the flood damage model RAilway Infrastructure Loss (RAIL)

2016 ◽  
Vol 16 (11) ◽  
pp. 2357-2371 ◽  
Author(s):  
Patric Kellermann ◽  
Christine Schönberger ◽  
Annegret H. Thieken
Keyword(s):  
Risk Management ◽  
Risk Aversion ◽  
Flood Risk ◽  
Structural Damage ◽  
Large Scale ◽  
Damage Model ◽  
Flood Damage ◽  
Railway Infrastructure ◽  
Increased Risk ◽  
The Impact

Abstract. Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than EUR 100 million due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate (1) the expected structural flood damage and (2) the resulting repair costs of railway infrastructure due to a 30-, 100- and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.

Estimates of future flood risk in Western Europe and its potential impact on insured losses.

2021 ◽  
Author(s):  
Remi Meynadier ◽  
Hugo Rakotoarimanga ◽  
Madeleine-Sophie Deroche ◽  
Sylvain Buisine
Keyword(s):  
Climate Change ◽  
Flood Risk ◽  
Large Scale ◽  
Western Europe ◽  
Complex Nature ◽  
Flood Risks ◽  
Hazard Exposure ◽  
Modelling Framework ◽  
Loss Modelling ◽  
The Impact

<p>The large-scale and complex nature of climate change makes it difficult to assess and quantify the impact on insurance activities. Climate change is likely affecting the probability of natural hazard occurrence in terms of severity and/or frequency.</p><p>Natural catastrophe risk is a function of hazard, exposure and vulnerability. As a (re)-insurer it is seen that changes in year-on-year losses are a function of all these components and not just the hazard.</p><p>The present study focuses, in a first step, on assessing impacts of climate change on fluvial flood risks in Europe solely due to changes in hazard itself. A stochastic catalogue of future flood risk events is derived from Pan-European data sets of river flood probability of occurrence produced within EU FP7 RAIN project. The loss modelling framework internally developed at AXA is then used to provide a geographical view of changes in future flood risks.</p><p> </p>

scholarly journals Link between Land Use and Flood Risk Assessment in Urban Areas

Proceedings ◽  
2020 ◽  
Vol 30 (1) ◽  
pp. 62
Author(s):  
Zahra Kalantari ◽  
Johanna Sörensen
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Green Infrastructure ◽  
Flood Risk ◽  
Urban Areas ◽  
Land Use Changes ◽  
Drainage System ◽  
Property Owners ◽  
Pluvial Flooding ◽  
The Impact

The densification of urban areas has raised concerns over increased pluvial flooding. Flood risk in urban areas might increase under the impact of land use changes. Urbanisation involves the conversion of natural areas to impermeable areas, causing lower infiltration rates and increased runoff. When high-intensity rainfall exceeds the capacity of an urban drainage system, the runoff causes pluvial flooding in low-laying areas. In the present study, a long time series (i.e., 20 years) of geo-referenced flood claims from property owners has been collected and analysed in detail to assess flood risk as it relates to land use changes in urban areas. The flood claim data come from property owners with flood insurance that covers property loss from overland flooding, groundwater intrusion through basement walls, as well as flooding from drainage systems; these data serve as a proxy of flood severity. The spatial relationships between land use change and flood occurrences in different urban areas were analysed. Special emphasis was placed on examining how nature-based solutions and blue-green infrastructure relate to flood risk. The relationships are defined by a statistical method explaining the tendencies whereby land use change affects flood risk.

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