The Walloon Region is the southern part of Belgium. It extends over 18.000 km2 and is drained by two main rivers, the Meuse and the Scheldt. The tributaries of the Meuse are known for their extremely varied characteristics with high flows in winter and very low waters in summer. The altimetry of the basin varies from 60 m to 700 m above sea level. Floods in the Meuse basin are usually produced by continuous rainfalls during several winter days (Dal Cin et al. 2005). The Scheldt has a totally different behaviour. Since the basin topography is almost flat, it is mainldy prone to flash flood events. Radar developments for hydrological applications in the Walloon Region are the result of a collaboration between the Royal Meteorological Institute of Belgium (RMI) and the Hydrological Service of the Ministry of Equipment and Transport of the Walloon Region (SETHY). Two weather radars are operational in Belgium: the radar of Wideumont which is operated by RMI and the radar of Zaventem operated by Belgocontrol (air traffic safety). The Météo-France radar of l’Avesnois provides also a good coverage of the region. The locations of these radars are given in Fig. 1. A first assessment of the hydrometeorological potential of weather radar in this region has been performed through a cooperation with the Wageningen University (Berne et al. 2005). In the present paper, we describe the most recent developments concerning the hydrological use of the Wideumont radar.