L’Adda and “navigli” in Lombardie
The VEV network was bound to pay homage to Italy, cradle of the European Renaissance, where mathematicians and engineers had become the masters of canal construction in the 15th century. Italy certainly takes credit for introducing double, swinging mitre lock gates of the type still used almost universally today.
The “Naviglio” di Martesana, built between 1462 and 1470 by Bertola da Novate (1410-1475), is an example. Diverting flow from the river Adda at Trezzo, it follows the course of this river for 8 km before heading west across the plain of Lombardy to Milan, covering a total distance of 38 km. It was originally built with two locks and an aqueduct with three spans of 18m across the river Molgora. This aqueduct was the first to be built exclusively for navigation. Smaller streams were culverted under the canal by siphons of a design adopted later by the engineers of the Canal du Midi.
Leonardo da Vinci contributed to the improvement of lock design and building techniques. He also designed the first project for a lateral canal at Paderno, to by-pass the rapids of Adda and thus fulfil the Milanese dream of an uninterrupted inland waterway between Milan and Lake Como. The idea matured thanks to dedication of architect and painter Giuseppe Meda, author in 1574 of a remarkably ambitious project on this difficult site, with a lock of almost 18m drop. Construction of the Paderno Canal was finally approved by the King of Spain in 1590, but work proceeded slowly, in a political and economic context that was fraught with difficulty.
Meda died in August 1599, and with him all ambitions for completion of the enterprise. The water introduced into the first section in 1603 was drained completely in 1617. The towns of Como and Bergamo kept up their fierce opposition to this navigable link, which threatened their respective trading positions. A new “grand design” was needed to put the project back on the agenda. This was the case under the Austrian administration (1748-1796).
The studies were revised by count Firmian, representative of Austria in Lombardy, who asked the engineers and mathematicians Pecis, Lecchi, De Regis and Frisi to conduct the work. Contractor Nosetti was awarded the works in 1773. The project provided for reuse of Meda’s lock foundations, but with the height of the downstream lock reduced to about a third of that in Meda’s original plan.
Nosetti doubted the feasibility of a lock as deep as that proposed by Meda, and envisaged breaking up the difference in level of 30m into six pounds instead of two. The canal was opened to navigation on October 11, 1777 in the presence of count Firmian and the Archduke of Austria. However, a structural failure at one of the locks delayed final opening of the canal until two years later.
While commercial navigation declined during the 19th century, other uses appeared or expanded, in particular irrigation, and towards the end of the century the landscape of the Adda valley was totally transformed by the arrival of hydroelectric power.
The heritage of the valley of Adda is thus today a valuable combination of technical monuments and natural landscapes, the conservation of which has became a specific issue for the Region, despite the fact that the canals have been abandoned as navigations. Their restoration, for uses that remain to be defined, is now clearly on the agenda, and the Region intends to make a success of their rehabilitation as visitor routes, a leisure amenity for the Milanese conurbation and infrastructure for didactic projects on the history of the hydraulic techniques, omnipresent in the region.