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The Vajont Dam or Vaiont Dam is a disused hydro-electric dam in the valley of the Vajont river under Monte Toc, in the municipality of Erto e Casso, 100 kilometres (60 mi) north of Venice, Italy.

The dam was conceived in the 1920s and eventually built between 1957 and 1960 by Società Adriatica di Elettricità, at the time the electricity supply and distribution monopoly in northeastern Italy. In 1962, the dam was nationalized and came under the control of ENEL as part of the Italian Ministry of Public Works. On 9 October 1963, during initial filling of the lake, a landslide caused a megatsunami in which 50,000,000 m3 (1.8×109 cu ft) of water overtopped the dam in a wave of 250 m (820 ft), bringing massive flooding and destruction to the Piave Valley below, destroying several villages and towns, causing an estimated 1,900 to 2,500 deaths. The dam remained almost intact and two-thirds of the water was retained behind it. This event occurred after ENEL and the Italian government concealed reports and dismissed evidence that Monte Toc, on the southern side of the lake, was geologically unstable. Underestimating the size of the landslide, ENEL's attempt to safely mitigate any landslide by lowering the level of the lake came too late, when disaster was almost imminent.

The dam was built by Società Adriatica di Elettricità (SADE), the electricity supply and distribution monopoly in northeastern Italy. The "tallest dam in the world", across the Vajont Gorge, was conceived in the 1920s to harness the Piave, Maè, and Boite Rivers, to meet the growing demand for power generation and industrialization.

On 22 March 1959, during construction of the Vajont Dam, a landslide at the nearby Pontesei Dam created a 20-metre-high (66 ft) wave that killed one person. The tests indicated that a wave generated by a landslide could overtop the crest of the dam if the water level was 20 m (66 ft) or less from the dam crest.

Hypothesis of a partial breakage of the dam and consequent examination of the rout wave and its propagation along the last stretch of the Vajont and along the Piave, up to Soverzene and beyond

With the reported experiences, carried out on a 1:200 scale model of the Vajont lake-reservoir, we tried to provide an evaluation of the effects that will be caused by a landslide, which is possible to occur on the left bank upstream of the dam. . EXAMINATION ON THE HYDRAULIC MODEL OF THE EFFECTS OF A POSSIBLE LANDSLIDE IN THE VAJONT LAKE TANK Near the dam (and a maximum of 31 metres (102 ft) at 430 metres (1,410 ft) from it) an overflow just over 2,000 cubic metres per second (71,000 cu ft/s).

In 20 seconds it reached the water level; by 45 seconds the landslide (now at rest) had completely filled the Vajont reservoir. The third wave (containing about 50×10^6 m3 (1,800×10^6 cu ft) of water) rose over the edge of the dam, which remained intact except for the roadway that led to the left side of the Vajont, and fell into the narrow valley below the dam.

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.

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".

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.

Suburban Emergency Management Project (SEMP), 'Epic Vajont Dam Disaster, Italy, 1963: Manmade or Natural?', Biot #373: 17 June 2006.

Quick Facts

• The dam is located in the valley of the Vajont river under Monte Toc, in the municipality of Erto e Casso, 100 kilometres (60 mi) north of Venice, Northern Italy.
• In 1962, the dam was nationalized and came under the control of ENEL as part of the Italian Ministry of Public Works.
• On 22 March 1959, during construction of the Vajont Dam, a landslide at the nearby Pontesei Dam created a 20-metre-high (66 ft) wave that killed one person.
• The dam was conceived in the 1920s and eventually built between 1957 and 1960 by Società Adriatica di Elettricità, at the time the electricity supply and distribution monopoly in northeastern Italy.
• The dam remained almost intact and two-thirds of the water was retained behind it.

Source material: Wikipedia - "Vajont Dam". Adapted and summarized for DiscoverScroll. Original contributors are credited through the linked Wikipedia article. Read original on Wikipedia. CC BY-SA 4.0. Changes were made from the original.