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Landslides, earthquakes, and a murderous tsunami all caused by the Vajont Dam in Italy, one that engineers determined to make the tallest in the world

Boban Docevski

Humanity tends to play with the forces of nature, a sometimes dangerous game, but the rewards can be rich. In most cases we are successful, and we manage to harness some part of the energy of the Earth, but in some cases, we fail and hurt ourselves and the environment around us quite badly. Since the discovery of how to harness electricity, demands from society for a reliable supply have made its generation a lucrative prospect. The Vajont River Valley in Italy was earmarked as the perfect place to create a huge hydro-electric dam. After decades of planning, what was to become the tallest dam in the world was constructed between 1957 and 1960. But very soon, the Vajont River dam became the deadliest in the world.

This whole project was screaming “danger and failure” from the beginning. The idea for making a huge dam on the Vajont River first appeared in the 1920s. The world was changing, and Italy needed more and more power, especially in the years before World War II. Nevertheless, the dam idea was put on hold during the entire time Mussolini had power in the country. Finally, in 1943, after his regime fell, the dam was given the green light. Strangely enough, the contract for its construction was given to a company called SADE (Societa Adriatica di Elettricita); a company whose owner, Giuseppe Volpi di Misurata, was Italy’s minister of finance during Mussolini’s time.

It was a huge undertaking. When finished, the dam would have the capacity to hold as much as 220,670,000 cubic yards of water. It was supposed to collect the water from all nearby streams and valleys through a complex network of pipes and channels.

Despite the warnings and negative opinions of the locals, SADE managed to take the land where the dam was to be made by force. They started building in 1957 and, after two years, land shifts were noticed in the area around the dam. SADE previously claimed that they did all the necessary studies to prove the gorge and surrounding mountainous area (Monte Toc) was safe, but three independent studies have showed that the area is very unstable and that the mountainside could collapse. SADE decided to ignore the warning of the experts and continued working.

Vajont Dam as seen from the town of Longarone

Vajont Dam as seen from the town of Longarone


When full, the water in the artificial lake was supposed to reach a depth of 860 feet. In November 1960, the water reached the 620-foot mark and problems started to appear. First in a series of big issues was a landslide of 1,000,000 cubic yards that fell in the lake. The filling was stopped, and the lake level was reduced by 160 feet. As a measure of precaution, they built a reservoir in the basin in front of the damn; one which would prove to be useless. The following year, the filling continued. In 1962 several suspicious events took place. People from the nearby villages of Erto and Casso felt a total number of five grade-five earthquakes (Mercalli scale). SADE denied any connection with the earthquakes and ordered the dam to be filled to its maximum level.

SADE engineers again confirmed that the dam was safe. They estimated that if a landslide happened again, the wave caused by it could be stopped if the level of the water was reduced by 80 feet from the top point. The sounded pretty sure that they could beat the water. In March of 1963, the dam was nationalized and now came under the control of the government electricity service, ENEL.

In 1963, the artificial lake was filled almost to its capacity. During all this time people from the area kept reporting that something dangerous was happening. Small earthquakes continued to happen on a regular basis, small landslides were also regular, and then, on September 15 1963, the whole mountainside moved down 8.7 inches, a huge distance for a landmass this big. Around two weeks later, ENEL decided that it would be a good idea to lower the level of the lake. Unfortunately, this decision was made too late. Soon the whole mountainside moved almost 3.3 feet.

imposing the vajont dam of reinforced concrete between two mountains in Italy

imposing the vajont dam of reinforced concrete between two mountains in Italy

The most dreadful date pf all was October 9, 1963. During the day, SADE engineers noticed a few trees and rocks falling down from the unstable mountainside. Although alarmed, they were still sure their method of lowering the level of the lake would work. At exactly 10:39 P.M.,. a gigantic landslide carrying 340,000,000 cubic yards of trees, earth, and huge rocks unleashed itself toward the lake. All of this happened faster than anyone could imagine. Moving at a speed of 68 mph, the whole mountain side slid down in just 45 seconds. This was not the end; it was just the beginning. In the next few moments, this landslide caused an enormous and devastating mega-tsunami, a wave that was 820 feet high. One can only imagine the tremendous force that this amount of water carries with it.

The wave kept on going down the valley, destroying everything in its path. Nothing could stop it. Below the dam, there were the villages of Longarone, Pirago, Rivalta, Villanova, and Faè. When the wave came, they and 2,000 of their inhabitants were wiped from the face of the earth, buried in the mud and debris. Later, an impact crater that was 200 feet deep was discovered just beneath the base of the damn.

Dam Vaiont. Province Belluno, Italy.

Dam Vaiont. Province Belluno, Italy.

It was estimated that the water hit the dam wall with a force that was twice stronger than the Hiroshima atomic blast.

Read another story from us:  Itaipu Dam produces the most energy of any hydroelectric dam in the world

By some miracle, the dam survived this catastrophe. It received only minor damage and resisted the wave like some devilish force got into it. Today, it stands as a reminder of the consequences of our errors. Its message is that we always need to listen to the voice of those who know their job and forget about profit and power when human lives are in question.