Potential Change in Groundwater Discharge as Response to Varying Climatic Conditions - An Experimental Model Study at Catchment Scale

The possible change in groundwater discharge from a medium-scale catchment to the Baltic is studied by means of a numerical groundwater flow model. The test area northeast of Wismar (Mecklenburg-Vorpommern, Germany) is built by quaternary glaciofluvial sands and intercalated tills. Today's groundwater recharge is calculated as 24% of the recent average annual precipitation of 600 mm in the test area, and its submarine groundwater discharge is modelled to 14.3% of the precipitation. Based on climate scenarios calculated by the Swedish Meteorological and Hydrological Institute (SMHI) and the Hadley Centre (HC) three sea-level scenarios in combination with four precipitation scenarios are modelled for steady-state groundwater conditions in order to assess potential response in discharge. The temporal development is observed in a simplified schematic model for transient conditions. For the given conditions the influence of sea-level rise is almost not noticeable. However, the modelled scenarios indicate that changes in groundwater recharge as a consequence of climate-induced changes in precipitation lead to notable variations of submarine groundwater discharge.