1. Chief Engineer, Fairfax County Dept. of Public Works & Environmental Services, Land Development Services, Site Development and Inspections Division, 12055 Government Center Parkway, Suite 535, Fairfax, VA 22035; Adjunct Professor, Univ. of Maryland, Dept. of Civil and Environmental Engineering, College Park, MD 20742-3021 (corresponding author).
2. The Ben Dyer Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, College Park, MD 20742-3021.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, College Park, MD 20742-3021.