Assessing the groundwater vulnerability to nitrate pollution within the geospatial decision support system LandSupport

This work presents the new web-based, freely-available dynamical tool, named the nitrate fate tool, developed within the geospatial Decision Support system (DSS) of LandSupport, for the assessment of groundwater vulnerability to nitrate pollution. The tool is based on the coupling of the ARMOSA model and the extended transfer function model (TFM-ext). The first is used to simulate the crop growth dynamics and the consequent nitrate leaching within the rooting depth of the soil, where the biological activity happens and whereby Nitrogen is converted from one form to another. Then its outcomes feed the TFM-ext model to assess the transport of nitrate through the unsaturated zone till the groundwater table depth. The tool has also been extended using the COMPSs programming framework, that allows to parallelize the execution of multiple model runs. Principal inputs of the tool are: soil physical and hydrological properties, climate, type of crops and their management (tillage, irrigation, fertilization and residual management) and the groundwater table depth. Results of the model are shown through the LandSupport GUI both as coloured maps, representing the concentration of nitrate at the arrival to the water table at the end of the simulation period, and as cumulative charts of the solute arrival at the depth of interest. The work presents the tool implementation for three case studies, with different spatial scales and pedo-climatic conditions: Regione Campania, IT, Marchfeld, AT, Zala County, HU. These are shown as examples of application of the LandSupport DSS in supporting the Water and Nitrate directives, demonstrating that it represents a valuable instrument for public authorities, environmental planners, as well as agricultural extension services.