1. Researcher, Dept. of Water, UR ETBX, Bordeaux Regional Centre, IRSTEA, 50, Ave. de Verdun, Gazinet, F-33612 Cestas, France (corresponding author).
2. Senior Research Scientist, Dept. of Water, UR ETBX, Bordeaux Regional Centre, IRSTEA, 50, Ave. de Verdun, Gazinet, F-33612 Cestas, France.
3. Research Engineer, Dept. of Water, UR ETBX, Bordeaux Regional Centre, Irstea, 50, Ave. de Verdun, Gazinet, F-33612 Cestas, France.
4. Professor, M2N, IMATH, CNAM, 3 rue Conté F-75141 Paris Cedex 03, France.