1. Assistant Professor, Dept. of Biosystems Engineering, 203 Corley Building, Auburn Univ., Auburn, AL 36849-5417 (corresponding author).
2. Director, Center for Geospatial Information Technology, Associate Professor of Civil and Environmental Engineering, 308 Patton Hall, Virginia Tech, Blacksburg, VA 24061.
3. Director, Occoquan Watershed Laboratory, 9408 Prince William St., Manassas, VA 20110-5670.
4. Associate Director, Occoquan Watershed Laboratory, 9408 Prince William St., Manassas, VA 20110-5670.
5. Executive Director, Powell River Project, Associate Professor of Crop and Soil Environmental Sciences, 363 Smyth Hall, Virginia Tech, Blacksburg, VA 24061.