1. Ph.D. Candidate, Oklahoma State Univ., 209 Agricultural Hall, Stillwater, OK 74078-6016.
2. Professor and Orville L. and Helen L. Buchanan Endowed Chair, and Director and Berry Endowed Professor, Oklahoma Water Resources Center, Oklahoma State Univ., 245 Agricultural Hall, Stillwater, OK 74078-6016 (corresponding author).
3. Assistant Professor, Dept. of Environmental Engineering, College of Engineering, Al-Mustansiriya Univ., Baghdad, Iraq.