Das Projekt "Anwendung und Validierung hydrologischer Modelle - Wasserhaushaltsmodellierung in kleinen Einzugsgebieten - VHAMPIRE" wird vom Umweltbundesamt gefördert und von Ecole Polytechnique Federale de Lausanne, Institut d'Amenagement des Terres et des Eaux - HYDRAM durchgeführt. To improve hydrological modelling approaches, through identifying model weaknesses in reproducing actual internal catchment processes as well as investigating parameter variability, and to progress in understanding hydrological processes, through improved field observation and issues arising from modelling queries and outputs. The long-term objective is to provide reliable tools for assessing the hydrological consequences of environmental change and defining the land and watershed management strategies necessary to preserve water quantity and quality. General Information: A physically-based hydrological model (SHETRAN) and a parsimonious model (TOPMODEL) will be validated and improved using data from small experimental catchments, including work to ensure that the internal dynamics and processes of the catchments are properly represented. Submodels for precipitation interception in forests and for snow melting will be specially developed. A new generation of field techniques, including TDR (Time Domain Reflectometry), GPR (Ground Probing Radar) and GPS (Global Positioning System), are to be tested and used together with other field experiments to obtain data for internal validation of subsurface hydrology in small research catchments. The methodology for hydrological use of GPR at the hillslope and small catchment scales (soil water content, soil water reserve and water table delineation) will be developed through validation in a range of field conditions. Joint field campaigns are to be performed in the Vallcebre catchments (Southeast Pyrenees), an area with strong spatial and temporal heterogeneities in hydrological characteristics and process operation. The purpose of these campaigns is not only to gather field data, but also to create the best conditions for exchanging experience between researchers concerned with modelling and those concentrating on field work. Identifying model deficiencies and guiding field observations from model outputs is a primary objective of these campaigns. Other field campaigns, at a range of experimental sites in Spain, the UK and Switzerland will be performed for specific purposes (investigating the hydrological consequences of land use change, erosion processes, flow generation and partitioning, snow melting). Data from Experimental Catchments in Germany will be used to test models in other environmental conditions.