1. Research Hydraulic Engineer, USDA–Agricultural Research Service, Arid Land Agricultural Research Center, 21881 N. Cardon Ln., Maricopa, AZ 85238 (corresponding author).
2. Assistant Research Scientist, Dept. of Soil, Water, and Environmental Sciences, Univ. of Arizona, 429 Shantz Bldg. 38, Tucson, AZ 85721.
3. Laboratory Director and Research Hydraulic Engineer, USDA–Agricultural Research Service, Arid Land Agricultural Research Center, 21881 N. Cardon Ln., Maricopa, AZ 85238.
4. Research Hydraulic Engineer, USDA–Agricultural Research Service, Arid Land Agricultural Research Center, 21881 N. Cardon Ln., Maricopa, AZ 85238.