Engineer’s Tunnel Proposal Sparks Geological Debate in Local Council
Engineer Paolo Ferrari presented to a fairly large city council his project to connect the Basso Sarca and the Adige River basin with a long tunnel; he responded to requests for clarification and engaged in a somewhat pointless controversy with Vincenzo Ceschini regarding the existence or not of geological studies on the rocky layers beneath the Nago busa.
Ferrari, denying the existence of geological studies, was merely reporting what had been communicated to him by the technician tasked by the province to assess the feasibility of five different alternative hypotheses, obtained by combining long and short tunnels, single or double-bore tunnels, and upgrading the existing infrastructure.
This technician, when directly asked by Ferrari, replied that his calculations were approximate, carried out without the geological drilling that would be necessary for an actual project and not just a preliminary hypothesis.
On the other hand, Ceschini maintained that geological prospecting had been carried out, numbering at least 23 surveys, dating back to the times when engineer Gentilini, fifteen years earlier, drafted his project for a long tunnel from Lake Loppio to Linfano.
Debate over prospecting and Ferrari’s project features
This debate — whether to drill or not — was entirely pointless because both parties, both convinced they were right and ready to defend their positions fiercely, were actually referring to different things.
Apart from that, Ferrari’s project is the well-known one. Its main characteristic is to be a single-bore tunnel, but sufficiently wide to contain three lanes of traffic, two ascending (slow vehicles and normal traffic) and one descending.
It has not been clarified whether a single-bore tunnel nearly 3 kilometers long complies with regulations on traffic safety, which have become much more sensitive to such issues following the tragedy on Mont Blanc.
Costs and technical characteristics of the project
A compelling argument in favor of Ferrari’s project is the cost. While Tiso estimates a cost of 80 billion lire (with a short, single-bore tunnel, destined to increase by another 110 billion in the case of a long, double-bore tunnel), Ferrari claims that everything can be done for 60 billion, including a long tunnel below San Giovanni, a shorter tunnel at Loppio, and a small connecting viaduct between the tunnel exit and the plain of Linfano, crossing in the direction of San Giorgio.
