The Spatial Processes in Hydrology (SPHY) model is a hydrological modeling tool that can be used for a wide range of water resource management applications. The methodology used in the SPHY model is described in the following paragraphs: The SPHY model makes extensive use of the PCRaster functionalities 1 . PCRaster is a free, open-source software package for the development and application of spatiotemporal environmental models 3 . The model has been set up using a high spatial resolution of 30 meters, which is very relevant for supporting decisions on variable-rate irrigation 2 . The SPHY model includes modules for rainfall-runoff processes, cryosphere processes, and evapotranspiration processes 3 . The methodology used in the SPHY model is similar to that used in the Soil and Water Assessment Tool (SWAT) model 3 . The SPHY model can be applied to flexible ranges of spatial scales, such as small-scale farms, medium-scale sub-catchment and catchment, and large-scale regional and glo