1. Hydrologist, Illinois State Water Survey, Prairie Research Institute, Univ. of Illinois, 2204 Griffith Dr., Champaign, IL 61820 (corresponding author).
2. Director, Illinois State Water Survey, Prairie Research Institute, Univ. of Illinois, 2204 Griffith Dr., Champaign, IL 61820.
3. Environmental Protection Specialist, Bureau of Water, Illinois Environmental Protection Agency, 1021 North Grand Ave., Springfield, IL 62702.
4. Graduate Research Assistant, Dept. of Agricultural and Biological Engineering, Univ. of Illinois, 1304 W. Pennsylvania Ave., Urbana, IL 61801.
5. Associate Professor, Dept.of Agricultural and Biological Engineering, Univ. of Illinois, 1304 W. Pennsylvania Ave., Urbana, IL 61801.