The Fortezza – Ponte Gardena section is approximately 22km long, excluding the technical tunnels  and the interconnections located to the North and South of the main track which count for additional 13km of structures.

ENSER has developed 3D numerical models to evaluate the potential water flow into the tunnel, and in currently carrying out a long term hydrogeological monitoring of the adjacent water bodies.

In the preliminary phases the following themes have been addressed:

• The definition of the hydrological and the hydrogeological balance;
• The evaluation of the hydraulic conductivity (K) of the soil units involved in the tunnel excavation;
• The analysis of the hystorical development of the hydraulic loads;
• The representation of the hydrogeological regime before the construction works and the hydrochemical and isotopic characterization of surface and underground waters.

Later the hydrogeological study took place in two main phases:

• Update of the hydrogeological model based on monitoring data and on the information of the Final Design;
• Implementation of a 3D numercal model covering an area of approximately 250kmq for the estimation of water flow into the tunnel.

The geotechnical and geomechanical study is currently in progress.