GIS-based method for groundwater management and protection: geotypes serving 3D applications

Sustainable management of underground natural resources is more and more a worthwhile topic. In particular, worrying about groundwater protection becomes imperative. Taking into account the increase of incompatibilities between water conservation and the use of other underground resources, the Geolep laboratory brought one of its research axes around to new methods for groundwater resources assessment and management. As these methods have to be as transparent as possible, we implemented a GIS to use standardized protocols to realize new maps of groundwater protection areas and resources index and, in a second step, to determine where it should be possible to install geothermal heat pumps without endangering drinkable water resources (OFEV, 2009). These methodologies are both based on the use of the geotypes, which is a new classification for geological formations (Parriaux and Turberg, 2007); it involves the use of genetic standards for loose material (e.g. lodgement till) and lithologic standards for hard rock (e.g. sandstone). Forty-one geotypes and their properties in relation to groundwaters were thus integrated in a GIS and completed with geophysical and boreholes data. The achievement of the new groundwater protection areas maps is currently in the pipeline for the whole canton of Vaud, while the implementation of the new methodology forgeothermal heat pump admissibility mapping (riquiring the building of a 3D geological model) is still being tested.