Water management in a densely populated area with a strong interplay between meteorological, hydrological and socio-economic drivers is a complex topic. In order to guarantee the supply of water, and to avoid drought and flood damage an efficient system of weather forecasting, impact assessment and hydrological engineering is required. Even in a well-developed country as The Netherlands the current operational systems still lack skill and appropriate interconnectivity to ensure efficient water management at various time and spatial scales. Apart from precipitation, uncertainty in surface evaporation forms a strong bottleneck for water management at local, regional and national scale. The proposed research focuses on enhancing the added value of available observations and medium- to seasonal range weather forecasts of particularly evaporation and related quantities (soil moisture, ground water, streamflow, lake levels). It will develop an upgraded monitoring and forecasting system for surface evaporation, using a scientific methodology to reduce existing gaps between different modelling and observational approaches. The system will be demonstrated in a case study area that is governed by the complex interactions determining water supply and demand.