[en] The operational management of rivers during low flows periods needs a best knowledge of the hydrological processes involved. Therefore a study aiming at the regionalization of low flows discharges in the Walloon Region has been started. Its first objective is to characterise the lowest flows throught existing monitoring network. Homogeneous regions will be defined on the basis of the results obtained. For each one, regression equations will be build in order to permit the computation of low flow discharge at any point of an ungauged river.