The Brenner Base Tunnel - a new link through the Alps

27 The team of experts also regularly take water samples to analyse its chemical composition in the lab. The Brenner Base Tunnel is being built at a great depth and for the most part through dense rock. This implies only a very slight risk of any water sources drying up. However, should the water balance along the project area change, there are already measures in place that can be implemented immediately so that there is no adverse effect on water supply. In addition to its use for documentation, the data collected is also used as a basis for hydrogeological models. For this purpose the mountain is divided into hydrogeological zones depending on the permeability of the rock. This allows flow systems at different depths to be determined. Experts regularly take water samples for analysis in accredited laboratories. Between Innsbruck and Fortezza there are now more than 1,300 measurement locations where the quality of surface and underground waters is measured. The properties of the water, such as the flow in springs and streams, groundwater levels, temperature and conductivity are ascertained before, during and after the construction of the tunnel. The amount of rainfall is also closely monitored. This enables the team to understand whether any changes in the water level are due to tunnel construction or variations in rainfall.