An outcome of an international conference (Wageningen, The Netherlands, 2000), this volume includes the Wageningen Statement, containing recommendations to governments and international organizations. The themes: risk assessment by monitoring, model development, and decision support, are considered at the levels at which policy development and water management take place: the agricultural production unit, the regional and the national level. Attention is given to alternative approaches for policy making and communication between the parties involved. The International Association of Hydrological Sciences is the world's premier member-based organization promoting the study and practice of Hydrology. Our books are authored, edited and produced at the highest level of quality, with the most current and thorough research. Our publications and our work advance the science and the professional practice of Hydrology in a variety of Science and Engineering fields around the world. The areas that we publish in include: • Ground water • Surface water • Snow and ice hydrology • Drought and desertification • Runoff modelling • Watershed • Remote sensing • Water quality • Water resources and management • Ecohydrology/hydro-ecology • Erosion and sediment • Tracer hydrology