Groundwater modelling of Färgaren 3 in Kristianstad - Simulations in MIKE SHE based on two extraction scenarios and different hydrogeological settings

Sammanfattning: This thesis aims to describe the hydrogeology and the groundwater flow variations in the area around Färgaren 3 in Kristianstad. The site was occupied by a dry-cleaning business between the years 1906 and 1988 and is now heavily contaminated with the chlorinated solvent perchloroethene (PCE). PCE, and some of its degradation products, are highly toxic. Spreading to the underlying sandstone aquifer, which is the largest groundwater resource in Sweden, could therefore have devastating effects. A previously established regional groundwater model, in the modelling software MIKE SHE, forms the basis in this thesis. A sub-model, covering the area of interest is created, and is updated to attain a more detailed description of the local geology. Groundwater simulations are performed based on two different extraction scenarios, and using different versions of the updated groundwater model. The results of the simulations show that the increased extractions from the sandstone aquifer during the twentieth century have had a major effect on the groundwater flow in the sub-model area. From being a discharge area, a large part of the area, including the contaminated site, is now a recharge area. Furthermore, the horizontal flow direction is altered. The flow is, due to the large extractions, directed to the municipal wells in central Kristianstad. To evaluate the potential spreading of PCE in this direction further studies, including contaminant transport calculations and groundwater samplings, are highly recommended.