1. Associate Professor, Dept. of Civil Engineering and Environment and Water Research Center, Sharif Univ. of Technology, Tehran, Iran.
2. Tehran Engineering and Technical Consulting Organization, P.O. Box 15875-1681, Tehran, Iran; formerly, Graduate Student, Dept. of Civil Engineering, Sharif Univ. of Technology, Tehran, Iran.
3. Assistant Professor, Dept. of Civil Engineering and Environment and Water Research Center, Sharif Univ. of Technology, Tehran, Iran.
4. Professor, Dept. of Civil and Environmental Engineering and Hydrology Program, Univ. of California, Davis, CA 95616-8628.