1. Postdoctoral fellow, Dept. of Civil and Environmental Engineering, Univ. of Cincinnati, P.O. Box 210071, Cincinnati, OH 45221-0071 (corresponding author).
2. Engineer, MWH Soft, 1850 Foxhollow Dr., Cincinnati, OH 45255.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Cincinnati, P.O. Box 210071, Cincinnati, OH 45221-0071.