Regionalization of an hourly rainfall generating model over metropolitan France for flood hazard estimation

The SHYPRE method is a flood risk estimation approach applicable on any point of a territory. It is based on the coupling of an hourly rainfall stochastic generator with a rainfall-runoff model. As a first step, carried out over the whole of France, regionalization of the hourly rainfall model parameters (obtained from 217 reference recording raingauges) was done on the basis of the available daily rainfall information. The information from 2812 raingauge stations was used to create maps of the rainfall model parameters at a scale of a one-square-kilometre pixel; data from 612 additional raingauges were used to validate this regionalization. Starting from these regionalized parameters, the rainfall model was used to obtain a geographic information system providing, at the square kilometre scale for the whole of France, the 1- to 72-hour maximum rainfall quantiles for 2- to 100-year return periods.