1. Dept. of Water Resources, School of Civil Engineering, National Technical Univ. of Athens, Heroon Polytechneiou 5, GR-15780 Zographou, Greece (corresponding author). E-mail: dk@itia.ntua.gr
2. Dept. of Water Resources, School of Civil Engineering, National Technical Univ. of Athens, Heroon Polytechneiou 5, GR-15780 Zographou, Greece.
3. National Foundation for Agricultural Research, Institute of Iraklio, 32A Kastorias str., 71307 Iraklio, Greece.
4. Dept. of Civil and Environmental Engineering, Univ. of California Davis, 662 Diego Place, Davis, CA 95616.