1. Research Hydraulic Engineer, USDA-Agricultural Research Service Hydraulic Engineering Research Unit, 1301 N. Western, Stillwater, OK 74075. E-mail: sherry.hunt@ars.usda.gov
2. Agricultural Engineer, USDA-Agricultural Research Service Hydraulic Engineering Research Unit, 1301 N. Western, Stillwater, OK 74075. E-mail: kem.kadavy@ars.usda.gov
3. Professor, College of Engineering, Dept. of Civil Engineering, Colorado State Univ., Fort Collins, CO 80523-1301. E-mail: sabt@engr.colostate.edu
4. Research Hydraulic Engineer, Retired, USDA-Agricultural Research Service Hydraulic Engineering Research Unit, 1301 N. Western, Stillwater, OK 74075. E-mail: darrel.temple@ars.usda.gov