The Gleno Dam was a
multiple arch buttress dam on the Gleno Creek in the Valle di Scalve, northern
Province of Bergamo
The Province of Bergamo ( it, provincia di Bergamo; lmo, proìnsa de Bèrghem) is a province in the Lombardy region of Italy. It has a population of 1,112,187 (2017), an area of , and contains 243 ''comuni''. Its capital is the city of Bergamo.
...
, Italy. The dam was built between 1916 and 1923 with the purpose of producing
hydroelectric
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...
power. The middle section of the dam
collapsed on 1 December 1923, forty days after the reservoir was filled, causing widespread flooding that killed at least 356 people.
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Construction
The dam was proposed and constructed by the Viganò company. A request to construct it was submitted in 1907 and construction began in 1916. In 1920, construction began on the foundation. In September of that year, local officials were warned that contractors were not using proper cement mortar. In 1921, because of lack of funding, the project design was changed from a gravity dam
A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation to oppose the horizontal pressure of water pushing against it. ...
to a multiple-arch type. The revised design was approved: the multiple arch dam would be constructed on top of the gravity dam foundation.
By January 1923, the dam was 80% complete and by October 22, it was fully complete and its reservoir full after heavy rains. The dam's power plant had an installed capacity of 3,728 kW (3.7 MW).
Failure
At 6:30am on December 1, 1923, a buttress on the dam cracked and subsequently failed. Within minutes, an estimated of water gushed from the reservoir at an elevation of to the valley below. The village of Bueggio was flooded first, followed by a partial flooding of Dezzo, part of the municipality of Azzone
Azzone (; lmo, label=Bergamasque, Sù) is a ''comune'' (municipality) in the Province of Bergamo in the Italian region of Lombardy, located about northeast of Milan and about northeast of Bergamo. As of 31 December 2004, it had a population ...
, and complete flooding of Dezzo, a frazione
A ''frazione'' (plural: ) is a type of subdivision of a ''comune'' (municipality) in Italy, often a small village or hamlet outside the main town. Most ''frazioni'' were created during the Fascist era (1922–1943) as a way to consolidate territ ...
of Colere
Colere (Bergamasque: ) is a ''comune'' (municipality) in the Province of Bergamo in the Italian region of Lombardy, located about northeast of Milan and about northeast of Bergamo. As of 31 December 2004, it had a population of 1,147 and an area ...
and Corna di Darfo. The flood waters stopped when they reached Lake Iseo, which lies at an elevation of . At least 356 people were killed in the disaster.[
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Investigation
The dam was originally permitted as a gravity dam with a slight curvature, but was changed to a multiple arch dam by the client to save money.
The permit was not revised for this change until after the dam was completed. The failure of the multiple arch dam was attributed to many aspects of its construction, ultimately poor workmanship. The concrete in the arches was of a poor quality and it was reinforced with anti-grenade scrap netting that had been used during World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
.
There were also indications that the dam was poorly joined with its foundation.[ Additionally, the concrete was believed to not be completely cured when the reservoir was filling. Reportedly, workers who complained about the construction techniques were fired.
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Legacy
The dam's failure was influential in the development of Italian dam design and risk assessment. As a result of the accident, multiple arch dams fell out of favour.
A much smaller dam was built spanning the gap left by the collapse, and is still in use today, creating a minor reservoir. A memorial at the site commemorates the tragedy.[
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References
External links
Gleno Dam History
at Scalve.it (Italian and English)
{{Authority control
Dam failures in Europe
Dams in Italy
1923 industrial disasters
Dams completed in 1923
Province of Bergamo
Hydroelectric power stations in Italy
1923 in Italy