1. Staff Engineer, Tetra Tech, 4900 Pearl East Cir. #300W, Boulder, CO 80301-6118.
2. Environmental Engineer, Terracon, 15080 A Circle, Omaha, NE 68144.
3. Instructor, Civil, Water Resources and Environmental Engineering Technologies Program, Saskatchewan Institute of Applied Science and Technology (SIAST), Palliser Campus, Moose Jaw, Sasktachewan S6H 4R4, Canada.
4. Professor, Dept. of Civil Engineering, Univ. of Nebraska, Lincoln, NE 68588-0531 (corresponding author).