Dams in Italy: which is the largest one?

Italy’s 532 dams are constantly monitored

Sometimes, they are built to regulate river flow, therefore securing those living in nearby villages. At other times, they are used to create water reserves for agricultural purposes. And they are also used to generate electricity in hydropower plants, as the energy produced from waterfalls generates clean energy, without using fossil fuels.

Dams: engineering works of art created by Man, long ago, and transformed into evermore complex infrastructures. There are approximately an estimated 45,000 dams exceeding 15 metres in height: A large portion of these can be found in China (where there are approximately 22,000 dams) and in India (with approximately 4,000). Many dams have also been built in Italy. In fact, the territory’s configuration facilitates building these barriers. Italy also lacks local fossil fuel sources. Therefore, the Italian electric companies decided use hydropower as much as possible. But how many dams are there in Italy? And how tall is Italy’s tallest?

Dams in Italy: An overall scenario

How many dams are there in Italy? If we take a look at the largest, which exceed 15 metres in height, we can count a total of 532. These are constantly monitored by the Italian Dams and Hydroelectric Infrastructure Technical service. The smallest ones, those measuring less than 15 metres, are much more: managed by the relevant Italian regions, they range between 8,500 to 10,000 in number. In truth, many Italian Regions did not conclude the registrations of the number of dams with reduced height, so it is quite difficult to know how many of them actually exist.

In Italy, large dams are constantly monitored. Especially since 1963, when the Vajont Dam built between 1957 and 1960, in Friuli Venezia Giulia, was the protagonist of one of Italy’s worst historical tragedies: the Vajont Disaster with its 1,917 victims. In 1985, the attention increased once again, following the Stava Valley disaster, with its 268 deaths. Dams are now once again under the government's spotlight, after the Morandi Bridge collapsed, following which, it was decided to constantly monitor a large part of Italian infrastructure, dams first.

Not all the 532 large dams are in use. In fact, in 2018, only 382 of these large ones were operating, 32 were only partially used, due to technical reasons, 27 were unused, 11 were being built and 80 were undergoing experimental operation. In most cases, 61% of these large Italian dams are used to generate electricity. 26% of these dams are used to create water reservoirs for agricultural purposes, while 12% are dams used to supply drinking water.

Lombardy is the Italian region with the majority of dams, with 77 of them. Piedmont and Sardinia, follow, both with 59, then tailed by Tuscany and Sicily, with respectively 50 and 46 dams. In total, the total volume of water collected by all of Italy's large dams amounts to 12,752 million cubic metres (data provided by the Italian Ministry of Infrastructure and Transport for 2018).

Italy's largest Dam

Italy, as said, has over 500 large dams. But which is Italy's largest one?

Italy's largest dam is also the one linked to the saddest memories: the Vajont Dam, with its 255 metres of height. Visitors feel a certain giddiness, when they visit, as they recall the terrible tragedy of 1963, which somewhat always manages to hit at the very deepest. It must be mentioned that despite the huge wave of mud that came off the Toc Mountain (Monte Toc), the Vajont Dam still sits perfectly in its original place, and in perfect conditions too, therefore confirming the project's structural excellence. The impact absorbed by the dam was almost 10 times more to what normally expected during standard operating conditions. When it was built, the Vajont Dam was the world's largest artificial barrier. It now ranks 7th.

Italy's second largest dam, in height terms, is the Alpe Gera one, in Lombardy. Its 160.5 metres place it before the Santa Giustina one, in Trentino, which measures 147.5 metres. The Vajont and Santa Giustina dams are both arched, while the Alpe Gera one is a gravity dam.

Italy's oldest dam

Italian dams were certainly not built recently. Taking a brief look at when these large Italian dams were built, we can, in fact, easily discover that their average age is 62 years. The Italian Region, Liguria, has 13 dams built, on average, 86 years ago. In some cases, we are dealing, therefore, with huge structures created and designed a very long time ago. It therefore comes to no surprise if extraordinary maintenance interventions and earth-quake resistance re-assessments are now being made to secure these older dams.

And which are the oldest? The oldest Italian Dam is the one forming Lake Spina, in the municipality of Pralormo, in the Metropolitan City of Turin. Its 20-m-high earth-clay barrier holds approximately 1 million cubic metres of water. The dam was first mentioned in documents in 1827, which were signed by King Carlo Felice. Another dam worthy of mention is the Bunnari Bassa one, built between 1874 and 1879, and currently not operating. It is not an embankment, but of a 32-metre-high ordinary gravity stone dam.