A Regional Scale Hydrostratigraphy Generatedfrom Geophysical Data of Varying Age, Type, and Quality

In the present study, we show how persistent management and collection of hydrological andgeophysical data at a national scale can be combined with innovative analysis methods togenerate decision support tools for groundwater and surface water managers. This is exem-plified by setting up a regional scale groundwater model in an area with geophysical data ofvarying age, type, and quality. The structure for the regional model is derived from a newlydeveloped resistivity clay-fraction cluster analysis. This modelling strategy can be used incombination with local detailed geological modelling thus utilizing the detailed expertiselocally, while securing a cost-effective (price vs. performance) solution to the numericalsimulations of the regional scale water balance. In this way we avoid unwanted boundaryeffects on the local model simulations due to the presence of artificial numerical boundarieslocated proximate to the areas of interest. In this application, it is particularly important thatboundary conditions are remote, due to the presence of a dense network of buried valleystructures. Simulated impacts of groundwater abstraction from two existing well-fields spreadthrough the valley system far beyond the local focus areas of the study.