There have been warnings of a coming worldwide water crisis. Several observers urge sustainable management of the global water resources. Perspectives on Water provides the basic analysis needed for such a management strategy. To study the changing relationship between water and humans, the National Institute of Public Health and the Environment (RIVM) in Holland has developed the AQUA simulation model. This book introduces the model for the first time. Various 'possible water futures' are presented, based on different perspectives on how the world functions and should be managed. Arjen Hoekstra shows which risks are connected to different kinds of water policy strategy. Perspectives on Water offers an essential tool for planners, scientists and politicians.