Aon Benfield has launched a new flood model for Switzerland and Lichtenstein to quantify financial losses caused by riverine and lake flooding.
Flooding in Switzerland over the last two decades has caused human and financial losses across the entire country, for example in 1999, 2000, 2005 and 2007. As such, flood is considered to be the most significant natural peril in Switzerland.
In response, Impact Forecasting, Aon Benfield’s catastrophe model development centre of excellence, has created a model to calculate both probabilistic and historical loss estimates and in turn help insurance and reinsurance markets to better understand the risks they write in Switzerland.
The new tool reflects both locally-sourced data and the latest developments in hydrology and flood model development. Key features include:
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Some 12,000km of the river network is modelled, which covers nearly all property exposed to flooding from rivers and lakes
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Data of daily flows and water levels were taken from 200 lake gauging stations managed by FOEN (The Federal Office of Environment). On average, 57 years of data has been collected from the stations and up to 119 years in one case.
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A LiDAR (laser screen) based Digital Terrain Model (DTM) built by Swisstopo (Swiss Federal Office of Topography) is used to create flood maps with a very granular cell size of 5x5 metres (by comparison, DTM resolution in earthquake models is normally in kilometres)
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The probabilistic event set consists of 120,000 possible floods or 12 events per year for 10,000 years
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The use of Flowroute-iTM, a highly efficient 2-dimensional hydrodynamic flood model from Ambiental, a leading international flood risk assessment consultancy. Flowroute-i was used to improve the speed and efficiency of digital flood map creation using Ambiental’s advanced computing and data processing capabilities.
Petr Puncochar, flood model developer at Impact Forecasting, said: “The hazard component of the Swiss flood model is based on advanced hydrodynamic modelling, which describes the real physical behaviour of floods with improved accuracy. In particular, this approach enables better understanding of the complex Swiss topography which includes various hydrological regimes from low land to alpine.”
Markus Hauswirth, CEO of Switzerland for Aon Benfield, added: “What makes this model unique is that it is a true Swiss model created with local hazard and loss data from our clients, Swisstopo and the FOEN. This ultimately means insurers can more accurately model historical events and future events, in addition to analysing per-location inputs or portfolios aggregated by postal code or canton.”
Alan Gregory, co-CEO of Europe, Middle East and Africa for Aon Benfield, commented: “Insurers and reinsurers are demanding more sophisticated and open tools to quantify and manage the risks facing their businesses. There is a growing desire for transparency driven by regulatory requirements and rating agency recommendations and the Swiss flood model meets these crucial criteria. It is an invaluable tool for both insurers and reinsurers, enhancing both the understanding and evaluation of flood risk in Switzerland.”
The model is integrated in ELEMENTS – Impact Forecasting's proprietary loss calculation platform – which allows the application of insurance conditions at varying levels and also quantifies different sources of uncertainty.
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