Estimation des débits rares de crue pour les cours d’eau de la Région wallonne (Belgique)

Estimate of rare events flood discharges for Walloon rivers (Belgium)

¹ Unité d’Hydrologie & Hydraulique agricole, Génie Rural & Environnemental ; Faculté Universitaire des Sciences Agronomiques de Gembloux
² Service d’Etudes hydrologiques de la Région wallonne

Abstract

The estimate of the extreme flood discharges of the rivers of Wallonia (Belgium) fits into the flood cartography project financed by the Walloon Region. This project, initiated in 2004, consists in the cartography of the flood hazard and of the damages risk due to floods by overflowing rivers. The flood hazard maps are established on the basis of hydraulic modelling which requires the estimate of extreme flood discharges.The source data are the average hourly discharges acquired by the hydrological measurement networks of the Walloon Region. Extreme flood discharges, corresponding to return periods of 25, 50 and 100 years, are calculated by adjustment of a statistical law to series of maximum annual discharges or to series of peaks-over-threshold, in the case of recent historical records of observations. The software HYFRAN used here was developed by the University of Quebec.The flood cartography is established on a scientific basis and is associated to urban regulations of corresponding areas. It will have a positive impact on the citizens by providing tools useful to treat request of permit, to target protection measures or installations, to make easier crisis management...