1. Assistant Professor, Dept. of Irrigation & Hydraulics, Faculty of Engineering, Cairo Univ., Giza, Egypt.
2. Professor Emeritus, Dept. of Civil and Environmental Engineering, Univ. of South Carolina, 300 S. Main St., Columbia, SC 29208.
3. Mr. and Mrs. Irwin B. Kahn Professor and Chair, Dept. of Civil and Environmental Engineering, Univ. of South Carolina, 300 S. Main St., Columbia, SC 29208 (corresponding author).