WATERAGRI will integrate within the modelling framework the novel physico-chemical watervapour sorption isotherm and water retention characteristics (WVSI-WRC) model for unsaturated soils developed by USAL. Different from conventional models used in unsaturated subsurface hydrology, which are empirical, the new model is based on the underlying physics of pore surface adsorption and capillary condensation. For this reason, all parameters in the model have physical meaning. It gives the advantage to use the model to optimise the implementation of the new technologies and the design of water retention products in terms of their underlying physics. On the other hand, the model will be validated using the data collected from lab test and field observation.