In the entire world we are experiencing changing water resources needs mainly as a result of changes in land use. In developing countries the occupation of natural areas by agriculture is a major cause; economical reasons pushed by world globalization play also a major role. In both cases further global changes are expected as a result of climate change.Water availability is essential for socio-economic activities and citizens expect catchment managers to take the necessary measures for assuring quantity and quality for direct and indirect human consumption. The knowledge of the processes determining water fate, actual reserves and the capacity to forecast water consumption are essential for catchment manager’s decision making.Land use change drives the modification of three interdependent global variables of the watershed: evapotranspirated water, biomass production and soil organic matter content. The assessment of the consequences of land use changes requires the capacity for studying those global variables on an integrated way. Catchment models can simulate those interactions together with all the processes that determine plant dynamics and are major tools for integrated studies, essential to decision makers.The MyWater project aims at developing a water management system integrating satellite data, models and in situ data in order to improve knowledge and create the forecasting capabilities necessary to catchment managers, and at the same time optimizing the ratio cost/benefit of water resources monitoring.The specific products of the project are: 1) A webGIS data tool; 2) Tools for improving operational model exploitation; 3) Training and technological transfer.The MyWater consortium includes representatives of the type of users expected. For that reason the consortium includes European, African and Latin-American teams to work in selected case studies (Portugal, Greece, Netherland’s, Mozambique and Brazil).