In Switzerland, as in many parts of the world, alluvial groundwater is an essential resource for the supply of drinking water to large urban centres or for irrigation and food production. However, due to their shallow depth, the quality of the water in these aquifers is threatened by increasing human activities, overexploitation and climate change. The understanding of the phenomena affecting these aquifers is based on field observations, the development of conceptual and numerical models, and the comparison of these models with observations. One of the main difficulties in this context is the great spatial heterogeneity of alluvial groundwater. Thus, for example, understanding how a pollutant moves requires knowledge of the position of permeable and less permeable zones in the subsoil. This heterogeneity is generally very difficult to identify and leads to considerable uncertainty.

The objective of the Phenix project is to create a suite of tools allowing the most precise modelling possible, taking into account the uncertainties, of the quaternary acquifers. The idea of these tools is to be simple to use, fast and allowing the models to be updated easily. The tools developed will be tested on the aquifer of the Aare valley between Bern and Thune. In order to be able to improve the model of this aquifer, a non-invasive geophysical campaign will be carried out in this region.