Malpasset Dam Disaster

The Malpasset Dam was an arch dam on the Reyran River, located approximately 7 km north of Fréjus on the French Riviera (Côte d’Azur), southern France, in the Var département. It collapsed on December 2, 1959, killing 423 people in the resulting flood. The damage amounted to an equivalent total of $68 million.

The dam was a doubly curved equal angle arch type with variable radius. It was built to supply drinking and irrigation water for the region. Construction began in April 1952 and was finished in 1954. Another source reports that construction began as early as 1941. Delays due to lack of funding and labor strikes interrupted construction a few times. The project was led by well-known French engineer André Coyne. Construction cost 580 million francs (by 1955 prices), and was funded and owned by Var département. Concurrent with the dam construction, the A8 autoroute was also being built 1,400 meters further down the course of the Reyran from the dam location.

The dam was supposed to regulate the rate of the flow of the river that it was near and store 50 million cubic meters of water for agriculture, and domestic use and for the tourism sector of the area. The dam was 222 metres in width, 66 metres high, and had a thickness of 6.78 metres at the base and 1.5 metres at the rim.

France’s worst civil catastrophe of the 20th century. 

Malpasset after
Malpasset Dam Nowadays

During November 1959, there were the first warning signs: a “trickle of clear water observed high on the right [side]” and then cracks noticed later in the month in the concrete apron at the dam toe.

The dam was breached at 21:13 on December 2, 1959. This was partially due to the water level in the dam rising at a fast pace due to rainfall, and by noon on 2 December 1959 the reservoir had reached its maximum level. The guardian André Ferro asked for permission to release the excess water and was denied the ability to do so until 6pm of that day. The amount of water was by then so high that it took three hours to release only a few centimeters of water. The entire wall then collapsed with only a few blocks remaining on the right bank. Pieces of the dam are still scattered throughout the area.

The breach created a massive dam-break wave, or wall of water, 40 metres (130 ft) high and moving at 70 kilometres (43 mi) per hour, destroying two small villages, Malpasset and Bozon, the highway construction site, and in 20 minutes, still standing 3 metres (10 ft) high, reaching Fréjus. The water was recorded traveling at speeds up to 70 km/h with large chunks of the concrete wall some weighing up to 600 tons. Various small roads and railroad tracks were also destroyed, water flooding the western half of Fréjus and finally reaching the sea.

It was reported that the death toll of the dam breach was 423, with 135 children under the age of 15, 15 minors between 15 and 21 years old, 134 men, 112 women, and 27 individuals who were never identified. Separately, 79 children were orphaned. Additionally, 83 people were injured. The physical toll was higher with 155 buildings destroyed, 796 buildings damaged, and 1350 hectares destroyed, the amount of destruction totalling about 425 million euros in 2010 terms.

A lot of various simulations were done to model this disaster. This news is to present the SPH model based namely on the 2012 Ph. D. Thesis of Jie Zhao “Development of a fast SPH model for non linear shallow water flows: application to coastal flooting and dam breaking“.

SPH-flow Input Data

Dam 1
  • Fluid: water
  • NFM Boundary condition
  • Add border around the lake
  • Delta x=2.5m
  • Lake surface altitude = 100 m
  • Dam height = 50m
  • 3 153 062 particles
  • Physical time = 2000 s

Dam Free Surface Simulation

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