1. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249.
2. Chester and Helen Siess Professor, Director, Ven Te Chow Hydrosystems Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N Mathews Ave., Urbana, IL 61801.