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Vajont Dam

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Vajont Dam
LocationItaly
Coordinates46°16′02″N 12°19′44″E / 46.26722°N 12.32889°E / 46.26722; 12.32889
Construction began1956[1]
Operator(s)SADE – Società Adriatica di Elettricità
Dam and spillways
Height262 metres (860 ft)
Length160 metres (520 ft) (chord)[1]
Width (base)27 metres (89 ft) (89 ft)
Reservoir
CreatesLago del Vajont
The Vajont Dam as seen from the village of Longarone in 2005, showing approximately the top 60–70 metres of concrete. The wall of water that overtopped the dam by 250 metres (820 ft)[1] and destroyed this village and all nearby villages on 9 October 1963 would have obscured virtually all of the blue sky in this photo.[2]

The Vajont Dam (or Vaiont Dam)[3] is a disused dam, completed in 1959 in the valley of the Vajont River under Monte Toc, in the municipality of Erto and Casso, 100 km (60 miles) north of Venice, Italy. One of the tallest dams in the world, it is 262 metres (860 ft) high, 27 metres (89 ft) wide and 22.11 metres (72 ft 6 in) thick at the base and 191 metres (627 ft) wide and 3.4 metres (11 ft 2 in) thick at the top.[4]

The dam was conceived in the 1920s, designed by Carlo Semenza, and eventually built between 1957 and 1960 by Società Adriatica di Elettricità (SADE, or EDIS; English: Adriatic Energy Corporation), the electricity supply and distribution monopoly in northeastern Italy, then owned by Giuseppe Volpi di Misurata. In 1962 the dam was nationalized and came under the control of ENEL as part of the Italian Ministry for Public Works. It was described as 'the tallest dam in the world', intended to meet the growing demands of industrialization, and as of 2010 is still one of the tallest in the world.

On 9 October 1963, during initial filling, a landslide caused a megatsunami in the lake in which 50 million cubic metres of water overtopped the dam in a wave of 250 metres (820 ft),[1] leading to the complete destruction of several villages and towns, and 1,917 deaths. Although the dam itself remained almost intact and two-thirds of the water was retained behind it, the landslide was much larger than expected and the impact brought massive flooding and destruction to the Piave Valley below. This event occurred after the company and the Italian government concealed reports and dismissed evidence that Monte Toc, on the southern side of the basin, was geologically unstable. They had disregarded numerous warnings, signs of danger, and negative appraisals, and the eventual attempts to safely control the landslide by lowering the lake's level came when the landslide was almost imminent.

Construction

The dam was built by SADE, the electricity supply and distribution monopoly in northeastern Italy. The owner, Giuseppe Volpi di Misurata, had been Mussolini's Minister of Finances for several years. The 'tallest dam in the world', across the Vajont Gorge, was conceived in the 1920s to control and harness the Piave, Mae, and Boite rivers, and to meet the growing demand for power generation and industrialization. Not until the confusion after Mussolini's fall during World War II was the project authorized, on 15 October 1943.[citation needed]

The dam wall had a volume of 360,000 m³ and held up to 168,715,000 cubic meters of water. The dam and basin were intended to be at the centre of a complex system of water management in which water would have been channeled from nearby valleys and artificial basins located at higher levels. Tens of kilometres of concrete pipes and pipe-bridges across valleys were planned.[citation needed]

In the 1950s, SADE's monopoly was confirmed by post-fascist governments, and it bought the land despite opposition by the communities of Erto and Casso in the valley, which was overcome with government and police support.[citation needed] SADE stated that the geology of the gorge had been studied, including analysis of ancient landslides, and that the mountain was believed to be sufficiently stable.[citation needed]

Construction work started in 1957, but by 1959 shifts and fractures were noticed while building a new road on the side of Monte Toc. This led to new studies in which three experts separately told SADE that the entire side of Monte Toc was unstable and would likely collapse into the basin if the filling were completed.[5] All three were ignored by SADE. Construction was completed in October 1959, and in February 1960, SADE was authorised to start filling the basin.[citation needed] In 1962 the dam was nationalized and came under the control of ENEL as part of the Italian Ministry for Public Works.

Early signs of disaster

On 22 March 1959, during construction of the Vajont Dam, a landslide at the nearby Pontesei Dam created a 20-meter (66 ft) high wave that killed one person.[6]

Throughout the summer of 1960, minor landslides and earth movements were noticed. However, instead of heeding these warning signs, the Italian government chose to sue the handful of journalists reporting the problems for "undermining the social order".[citation needed]

On 4 November 1960, with the water level in the reservoir at about 190 metres (620 ft) of the planned 262 metres (860 ft), a landslide of about 800,000 cubic metres (1,000,000 cu yd) collapsed into the lake. SADE stopped the filling, lowered the water level by about 50 metres (160 ft), and started to build an artificial gallery in the basin in front of Monte Toc to keep the basin usable even if additional landslides (which were expected) divided it into two parts.[7]

In October 1961, after the completion of the gallery, SADE resumed filling the narrow reservoir under controlled monitoring. In April and May 1962, with the basin water level at 215 metres (705 ft), the people of Erto and Casso reported five "grade five" Mercalli intensity scale earthquakes. SADE downplayed the importance of these quakes.[8] SADE was then authorized to fill the reservoir to the maximum level.[citation needed]

In July 1962, SADE's own engineers reported the results of model-based experiments on the effects of further landslides from Monte Toc into the lake. The tests indicated that a wave generated by a landslide could top the crest of the dam if the water level was 20 metres (66 ft) or less from the dam crest. It was therefore decided that a level 25 metres (82 ft) below the crest would prevent any displacement wave from over-topping the dam. However, a decision was made to fill the basin beyond that, because the engineers thought they could control the rate of the landslide by controlling the level of water in the reservoir.[citation needed]

In March 1963, the dam was transferred to the newly constituted government service for electricity, ENEL. During the following summer, with the basin almost completely filled, slides, shakes, and movements of the ground were continuously reported by the alarmed population. On 15 September, the entire side of the mountain slid by 22 centimetres (8.7 in). On 26 September, ENEL decided to slowly empty the basin to 240 metres (790 ft), but in early October the collapse of the mountain's south side looked unavoidable: in one day it moved almost 1 metre (3 ft).

Landslide and wave

The lake behind the Vajont Dam, surrounded by forested mountains, and mostly filled with mud and debris.
Aerial view of the 'Valley-Vajont' area shortly after the disaster showing the lake filled with mud and debris from the landslide. The dam is in the foreground at left.
View of the village of Longarone, which was below the dam, showing the extent of the damage after the 'wave of death' had passed through.
The bell tower of a church, standing above flood debris.
The bell tower that remained standing at Longarone. The rest of the church building was swept away, as were almost all of the other structures in the village.

On 9 October 1963, engineers saw trees falling and rocks rolling down into the lake where the predicted landslide would take place. Before this, the alarming rate of movement of the landslide had not slowed as a result of lowering the water, although the water had been lowered to what SADE believed was a safe level to contain the displacement wave should a catastrophic landslide occur. With a major landslide now imminent, engineers gathered on top of the dam that evening to witness the tsunami.[citation needed]

At 10:39 pm, a massive landslide of about 260,000,000 cubic metres (340,000,000 cu yd) of forest, earth, and rock fell into the reservoir at up to 110 kilometres per hour (68 mph), completely filling the narrow reservoir behind the dam. The landslide was complete in just 45 seconds, much faster than predicted, and the resulting displacement of water caused 50,000,000 cubic metres (65,000,000 cu yd) of water to overtop the dam in a 250-metre (820 ft)-high wave.[1][2]

The flooding in the Piave Valley from the huge wave destroyed the villages of Longarone, Pirago, Rivalta, Villanova and Faè, killing around 2,000 people and turning the land below the dam into a flat plain of mud[9] with an impact crater 60 metres (200 ft) deep and 80 metres (260 ft) wide.[citation needed] Many small villages near the landslide along the lakefront also suffered damage from a giant displacement wave. Villages in the territory of Erto e Casso and the village of Codissago [it], near Castellavazzo, were largely wrecked.[citation needed]

Estimates of the dead range from 1,900 to 2,500 people, and about 350 families lost all members. Most of the survivors had lost relatives and friends along with their homes and belongings.[citation needed]

The dam was largely undamaged. The top 1 metre (3.3 ft) or so of masonry was washed away, but the basic structure remained intact and still exists today.[citation needed]

Causes and responsibility

Immediately after the disaster, the government (which at the time owned the dam), politicians and public authorities insisted on attributing the tragedy to an unexpected and unavoidable natural event.[citation needed]

The debate in the newspapers was heavily influenced by politics. The paper l'Unità, the mouthpiece of the Partito Comunista Italiano (PCI), was the first to denounce the actions of the management and government, as it had previously carried a number of articles by Tina Merlin [it] addressing the behaviour of the SADE management in the Vajont project and elsewhere. Indro Montanelli, then the most influential Italian journalist and a vocal anti-communist, attacked l'Unità and denied any human responsibility; l'Unità and the PCI were dubbed "jackals, speculating on pain and on the dead" in many articles by the Domenica del Corriere and a national campaign poster paid for by Democrazia Cristiana, the party of prime minister Giovanni Leone. They attributed the catastrophe only to natural causes and God's will.[10]

The campaign accused the PCI of sending agitprops into the refugee communities, as relief personnel; most of them were partisans from Emilia Romagna who fought on Mount Toc in the Second World War and often had friends in the stricken area.[11]

Democrazia Cristiana accused the Communist Party of "political profiteering" from the tragedy. Leone promised to bring justice to the people killed in the disaster. A few months after he lost the premiership, he became the head of SADE's team of lawyers, who significantly reduced the amount of compensation for the survivors and ruled out payment for at least 600 victims.[12]

The Democrazia Cristiana's newspaper, La Discussione,[13] called the disaster "a mysterious act of God's love", in an article that drew sharp criticism from l'Unità.[14]

Apart from journalistic attacks and the attempted cover-up from news sources aligned with the government, there had been proven flaws in the geological assessments, and disregard of warnings about the likelihood of a disaster by SADE, ENEL and the government.[citation needed]

The trial was moved to L'Aquila, in Abruzzo, by the judges who heard the preliminary trial, thus preventing public participation, and resulted in lenient sentencing for a handful of the SADE and ENEL engineers. One SADE engineer (Mario Pancini) committed suicide in 1968. The government never sued SADE for damage compensation.[citation needed]

Subsequent engineering analysis has focused on the cause of the landslide, and there is ongoing debate about the contribution of rainfall, dam level changes and earthquakes as triggers of the landslide, as well as differing views about whether it was an old landslide that slipped further or a completely new one.[15]

There were a number of problems with the choice of site for the dam and reservoir: the canyon was steep sided, the river had undercut its banks, and the limestone and claystone rocks that made up the walls of the canyon were inter-bedded with the slippery clay-like Lias and Dogger Jurassic-period horizons and the Cretaceous-period Malm horizon, all of which were inclined towards the axis of the canyon. In addition, the limestone layers contained many solution caverns that became only more saturated because of rains in September.[16]

Prior to the landslide that caused the overtopping flood, the creep of the regolith had been 1.01 centimetres (0.40 in) per week. In September, this creep reached 25.4 centimetres (10.0 in) per day until finally, the day before the landslide, the creep was measured at 1 metre (3.3 ft).[16]

Reconstruction

The area of the 1963 landslide on Monte Toc, taken in 2005

Most of the survivors were moved into a newly built village, Vajont, 50 km (31 mi) south-east on the Tagliamento River plain. Those who insisted on returning to their mountain life in Erto e Casso were strongly discouraged. Longarone and other villages in the Piave Valley were rebuilt with modern houses and farms.[citation needed]

The government used the disaster to promote the industrialization of the north-east of Italy. Survivors were entitled to 'business start-up' loans, public subsidies and ten years tax exemption, all of which they could 'sell on' to major companies from the Venice region. These concessions were then converted into millions of lira for industrial plants elsewhere. Among the corporations were Zanussi (now owned by Electrolux), Ceramica Dolomite (now owned by American Standard), Confezioni SanRemo, and SAVIC (now owned by Italcementi).[17]

Compensation measures did not clearly differentiate between victims and people who lived nearby; thus much of the compensation went to people who had suffered little damage, creating a negative public image.[citation needed]

A pumping station was installed in the dam basin to keep the lake at a constant level, and the bypass gallery was lengthened beyond the dam to let the water flow down to the Piave Valley. The dam wall is still in place and maintained, but there are no plans to exploit it. The dry basin, filled with landslip, has been open to visitors since 2002.[citation needed]

The dam today and memorials

In recent years there has been a revival of interest both by researchers with specialist interest, and sightseers. The dam, now owned by ENEL, was partially opened to the public in 2002 with guided tours and access to the walkway along the top and other locations. In September 2006 an annual non-competitive track event, called "Paths of Remembrance", was inaugurated, which allows participants to access some locations inside the mountain.

On 12 February 2008, in launching the International Year of Planet Earth, UNESCO cited the Vajont Dam tragedy as one of five "cautionary tales" caused by "the failure of engineers and geologists".[18]

For 2013, on the occasion of the fiftieth anniversary of the disaster, the region of Venice set aside one million euros for safety works and recovery of tunnels inside the mountain which were part of the Colomber Road (the old national road 251).

The memorial church in Longarone – constructed over the strong opposition of the surviving parish priest – is a late masterpiece of the famous architect Giovanni Michelucci.[citation needed]

In the media

After the initial worldwide reporting,[19] the tragedy became regarded as part of the price of economic growth in the 1950s and 1960s.

Interest was rejuvenated by a 1997 television program by Marco Paolini and Gabriele Vacis [it], "Il racconto del Vajont".

In 2001, a docudrama about the disaster was released. A joint production of Italian and French companies, it was titled Vajont—La diga del disonore ("Vajont—The Dam of Dishonour") in Italy, and La Folie des hommes ("The Madness of Men") in France. It stars Michel Serrault and Daniel Auteuil.

The tragedy was included in the 2008 documentary series Disasters of the Century.[20]

The TV show Seconds From Disaster featured the event in episode two, "Mountain Tsunami," of its fifth season in 2012.[21][22]

In 2013, the eleventh stage of the Giro d'Italia finished in Vajont to commemorate the fiftieth anniversary of the disaster.[23]

See also

References

  1. ^ a b c d e Petley, Dave (11 December 2008). "The Vaiont (Vajont) landslide of 1963". The Landslide Blog. Archived from the original on 14 January 2016. Retrieved 5 December 2019.
  2. ^ a b "The Vajont Dam Disaster – TeLL-Net Kick-off Assembly Kobe Japan 19–20 January 2006" (PDF). 20 January 2006. Archived from the original (PDF) on 27 March 2009. Retrieved 5 December 2019.
  3. ^ "Vaiont Dam photos and virtual field trip". University of Wisconsin. Retrieved 1 July 2009.
  4. ^ "Capolavoro d'ingegneria nel posto sbagliato". La Repubblica. Retrieved 19 September 2014.
  5. ^ T. Merlin, Sulla pelle viva, Cierre Edizioni, Verona, 1993, pp. 59 and 73.
  6. ^ See:
    • "Release of 50 million m3 of water at the Vajont Dam [on] 9 October 1963 [in] Erto e Casso (PN), Italy," French Ministry for Sustainable Development, November 2010, pp. 1–2. Available at: ARIA
    • Lago di Pontesei in Italian Wikipedia (in Italian)
  7. ^ A. De Nardi, Il bacino del Vajont e la frana del M. Toc, 1965, p. 27.
  8. ^ T. Merlin, ibidem, p. 102.
  9. ^ "Vajont, il muro d'acqua che ha ucciso Longarone". La Stampa. 9 October 2008. Retrieved 29 October 2012.
  10. ^ "Mattolinimusic.com". Mattolinimusic.com. Retrieved 29 October 2012.
  11. ^ "La rabbia e la speranza". Tinamerlin.it. Retrieved 29 October 2012.
  12. ^ "Vajont, Due Volte Tragedia". Sopravvissutivajont.org. 9 October 2002. Retrieved 29 October 2012.
  13. ^ La Discussione at Italian Wiki (temp ref)
  14. ^ L'Unità, 24 October 1963
  15. ^ David Petley. "Landslide information: The Vajont (Vaiont) Landslide, 2001". Land-man.net. Retrieved 1 January 2008.
  16. ^ a b M. Dane Picard, Mountains and Minerals, Rivers and Rocks: A geologist's notes from the field, Pub. Chapman & Hall (1993)
  17. ^ L. Vastano, Vajont, l'onda lunga, Salani Editore, Varese, 2008, pp. 80–3.
  18. ^ "Five Cautionary Tales and Five Good News Stories". International Year of Planet Earth – Global Launch Event. Latest Science Web News-lswn.it. 11 February 2008. ISSN 1827-8922. Retrieved 1 January 2009.
  19. ^ Towns wiped out in night of horror (Newsreel). MCA/Universal Pictures. 14 October 1963. National Archives Identifier 2050680. Retrieved 7 October 2013.
  20. ^ History Television, Vajont Dam Collapse. Retrieved January 2008.
  21. ^ "Seconds from Disaster, Schedule, Video, Photos, Facts and More – National Geographic Channel: Episode Guide – Series 5 – National Geographic Channel".
  22. ^ "Mega Disasters – Mountain Tsunami". 7 June 2015.
  23. ^ Cycling News, Giro d'Italia 2013 Stage 11

Bibliography

Video materials

Video on YouTube of 3D simulation of the wave generated by the Vajont rockslide.

Wikimedia Commons has media related to Vajont Dam.
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