Peter Waller trained as an irrigation engineer at the University of California at Davis. He then spent two years working as an irrigation sales engineer in California and Washington State. He received a doctorate in agricultural engineering at UC Davis and moved to the University of Arizona in 1994 where he is now an Associate Professor in the Agricultural and Biosystems Engineering Department. Dr. Waller's primary research areas include algae for biofuels, precision agriculture and irrigation, and he has taught irrigation and drainage courses at the University of Arizona for 20 years.

Muluneh Yitayew is Professor of Agricultural and Biosystems Engineering at The University of Arizona.  He got his B.S. degree in agricultural engineering from Haile Selassie I University, Ethiopia and his Ph.D. in civil engineering from The University of Arizona, USA.  After his PhD, he went to the University of California, Riverside to work as a research associate focusing on defining water duty for California.   He joined the Department of Agricultural and Biosystems at the University of Arizona in 1984.  Since then he has taught both undergraduate and graduate courses in irrigation engineering, drainage engineering, hydraulics, hydrology, hydraulic structures, and soil and water resources engineering to all levels of students at the University of Arizona, USA, Addis Ababa Institute of Technology, and Arba Minch University, Ethiopia. He has published numerous articles in various scholarly journals and authored several book chapters in civil engineering and irrigation.  Dr. Yitayew has also cooperated with international engineers and scientists in the Middle East, North Africa, East Africa and Europe for over thirty years.