1. Environmental Sciences, University of California, Riverside, CA 92507, USA now at: UNESCO-IHE Water Education Institute, Department of Hydroinformatics and Knowledge Management, PO Box 3015, 2601 DA Delft, The Netherlandsa.vangriensven@unesco-ihe.organd BIOMATH, Department of Applied Mathematics, Biometrics and Process Control, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
2. Environmental Sciences, University of California, Riverside, CA 92507, USA Now at: College of Engineering, Department of Hydrology and Water Resources, University of Arizona, 845 North Park Avenue, Tucson, AZ 85721-0158, USATel: +1 520 626153 Fax: +1 520 6211422 tmeixner@hwr.arizona.edu