Zeleke Agide Dejen, Irrigation Engineer by profession, has over 13 years of research, teaching and field experience in the area of irrigation engineering and water management. Currently, he holds a position of lecturer and researcher at Arba Minch University (a pioneer University in Ethiopia for water education and research). He has been conducting his PhD research since February 2010 at UNESCO-IHE Institute for Water Education in Delft the Netherlands which resulted in this book. His research interests are water management, irrigation system management, irrigation water distribution modelling, unsaturated zone modelling, flow control in irrigation, drainage and salinity control.