Val di Stava dam collapse

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In Tesero in Val di Stava (or Val di Fiemme / Val di Fiemme ) in the region of Trentino -Alto Adige, Italy on July 19, 1985 broke the dam of a settling tank of a mine and caused a tsunami that killed 268 people according to official figures.

Sedimentation basin

Two tanks were at different heights directly over or behind the other. They served as settling basins for the dumps of the mine of Prestavel the mining company fluorine mine.

The dams of these basins were more than 20 years old. The upper dam was 34 m high and the slope angle reached 80 % (40 °). The Gründungsfuge had a slope of 25%. In 1975, the dam systems were examined and classified as unstable and uncertain particularly the upper dam. The safety factors were extremely low.

The cause of the failure of a damaged drainage pipe is assumed in the dam, which was not repaired properly, as well as the endangered stability of the built of sand dam, since the sand vollsog with water and became unstable, and unusually large rain and snowmelt, the the upper reservoir congested.

Disaster

On 19 July 1985 at exactly 12:22:55 Clock of the upper dam broke, crashed into the lower basin and also brought its dam to break. A tidal wave of 180000-200000 m³ mud, sand and water flowed initially at 30 km / h Rio di Stava ( Stava Creek ) along by Stava and further at 90 km / h to the valley of the river Avisio down to Tesero, the 30 km away from Bolzano. More 40,000-50,000 m³ of soil, building rubble and uprooted trees were swept away. Everything on the way the tsunami was destroyed. In the tourist town of Tesero there was according to different reports, 200, 261, 264, 268, 269 or 361 deaths, the number of officially stated by the Stava Foundation is 268

Furthermore, 3 hotels, 53 houses, 6 and 8 industrial building bridges destroyed and 9 other buildings were badly damaged.

The sludge layer was 20 to 40 cm thick and extend to a length of 4.2 km over an area of ​​435,000 m².

The total loss is given as 155 million euros.

Process

After the break there was a criminal trial, which lasted until 1992. Ten persons were convicted of manslaughter, including the manager of the mine and the people responsible for the construction and operation of facilities and also in charge of the supervision authorities of the autonomous province of Trentino. The damage had to be carried from the operating companies and the provincial government. The last civil actions were not completed until 1999.

In addition, the judge noted that only one tenth of the legal costs would have been necessary to repair the dam professionally after its safety deficiencies in the study from 1975 had become known.

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