Pieter van der Zaag is professor of water resources management at the UNESCO-IHE Institute for Water Education and at Delft University of Technology, the Netherlands. He has special interests in agricultural water management, water allocation issues in catchment areas and in the management of transboundary river basins. Pieter is fascinated by the dynamic relationship between biophysical and social processes when managing water, which he tries to describe and analyse. He has been involved in several multidisciplinary research and capacity building projects mainly in Africa but also in Asia and Latin America. He is member of the governing board of WaterNet in Southern Africa, is associate editor of Water Policy and is member of the editorial board of Hydrology and Earth System Sciences. Pieter studied irrigation engineering at Wageningen University, the Netherlands. He obtained his PhD degree on a study of irrigation management in Mexico.