Aon Benfield has launched a new flood model for Switzerland and Lichtenstein aimed at quantifying financial losses caused by riverine and lake flooding.
Flood is considered to be the most significant natural peril in Switzerland and the new model calculates both probabilistic and historical loss estimates using locally-sourced data and developments in hydrology.
Key features are as follows:
Some 12,000km of the river network is modelled, covering nearly all property exposed to flooding from rivers and lakes.
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.
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 cell size of 5×5 metres (by comparison, DTM resolution in earthquake models is normally in kilometres).
The probabilistic event set consists of 120,000 possible floods or 12 events per year for 10,000 years.
The use of Flowroute-iTM, a two-dimensional hydrodynamic flood model from international flood risk assessment consultancy, Ambiental.
Aon Benfield chief executive officer for Switzerland, Markus Hauswirth, comments: “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.”