Steady-state hydrogeological modelling in order to investigate groundwater sensitivity.

Sammanfattning: Growing regions and tighter zoning in urban areas are pushing the hydrological bal-ances to establish new equilibriums which are causing a stress on the groundwater. Urbanization can affect the groundwater in several ways in which both raising and lowering of groundwater tables are a possibility. Both ways, sudden changes may bring on socioeconomic costs for the unprepared. Hydrogeological modelling creates the possibilities to visualise processes that cannot be seen with the naked eye. By combin-ing knowledge about the studied area from tests and measurements a conceptual model and additionally a numerical model can be created. To study the magnitude groundwater sensitivity to changes in land-cover a hydrogeological model was created using COMSOL multiphysics within the frame of a case study concerning a horse racetrack located in Täby, north of Stockholm. The model was calibrated against known data and was the applied on a future scenario where both the land-use and climate were changed. The outcome of the model showed that hydrogeological mod-elling is sensitive to the amount and quality of the in-data. Several insecurities in the results can be traced back to a lack of base material and by changing one parameter the result of other calibrated parameters would also change. Equifinality could thus be established to be a major issue when performing groundwater modelling. Further studies of relevant data requirements for different model objectives are required.