1. Research Assistant, Dept. of Civil Engineering, Hydraulics Unit, Univ. Catholique de Louvain, Place du Levant, 1, B-1348 Louvain-la-Neuve, Belgium.
2. Professor, Dept. of Civil Engineering, Hydraulics Unit, Univ. Catholique de Louvain, Place du Levant, 1, B-1348 Louvain-la-Neuve, Belgium.