Het gebruik van een Geografisch Informatiesysteem ten behoeve van het Landelijk Grondwater Model

Abstract

The current version of the "RIVM Groundwater Model for The Netherlands" (LGM) is used to calculate (the change in) groundwater heads and (changes in) seepage or infiltration due to changes in the hydrological system on a national scale. The geohydrological model is based on a system of four aquifers separated by semi-pervious layers (aquitards), bounded from below by impervious formations. From above, the system is possibly bound by the so-called top layer. The model consists of the finite element program package, AQ-FEM), for solving groundwater potential and flow problems, and the geographical information system (GIS) consisting of the software package ARC/INFO and data. AQ-FEM and the GIS are linked by interfaces providing for the conversion and transfer of data. Base data are resident within the geographical information system. Results of the calculations using the model are stored within the system for presentation and analysis purposes or to serve as input for other models. Development and application of the programs as well as their operation are described in this document. Its objective is, on the one hand, to provide insight into the structure, preparation and the flow of data in the LGM, while on the other it is meant to be a rough user's manuel for the LGM, along with some of the related documents published in the context of a study to predict the effects of groundwater extraction on the terrestrial ecosystems. This study was carried out in scientific support of the third governmental Policy Plan on Drinking and Industrial Water Supply.