1. Professor, Civil and Environmental Engineering Dept., California Polytechnic State Univ., San Luis Obispo, CA 93407 (corresponding author).
2. Director, Global Waste Research Institute, California Polytechnic State Univ., San Luis Obispo, CA 93407.
3. Engineer II, Hatch Mott MacDonald, Pleasanton, CA 94588.
4. Staff Engineer, Hultgren-Tillis Engineers, Concord, CA 94520.