The Disaster Of The Wyong Dam

People have tried to shape rivers to suit their needs from time immemorial. The dam created by this effort plays an essential role in the overall human construction. The concept of the dam is very simple. It is a wall that holds water from a river. Today, dams are used to create freshwater reservoirs, prevent soil erosion, and control flooding, and since the 20th century, the use of dams to generate hydropower has become one of the world’s major multi-purpose human engineering projects.

However, there are many instances in world history where such projects have failed due to environmental or construction defects. Such was the case with the Wyoming Dam in Italy, where more than 2,000 people lost their lives. Although such accidents are usually caused by flooding caused by dam breakage, the specialty here is that no damage is done to the dam.

Construction of Wyong Dam

After World War II, Europe’s economy grew rapidly. In almost every country, government spending was cut by about 75% of GDP. Italy, too, increased its GDP by 6% during the period 1950-63 and achieved high economic growth of 8.3% by 1961. As a result, investments flowed in, laying the foundation stone for the Wyong Dam project to generate electricity.

Location of Wyong Dam /

The dam will cross the Wyong River, a tributary of the Piave River. It is located in the longarone region, about 60 miles from Venice, Italy. The Wyong Narrow Dam was built to connect the two mountains of Caso and Tok above the city of longarone. The reservoir was planned to be filled by a sloping basin between the limestone hills. The bottom of the reservoir valley is about 4800 feet to the top of the Tok Peak with a vertical slope.

The dam, which began construction in July 1957, has two arches. It is 262 meters (860 feet) high and 160 meters long. The width of the bottom of the dam is 27 meters, and the width of the top is 3.4 meters. Its total water capacity exceeds 168 million cubic meters. The company that built the Wyong Dam was the Adriatic Energy Corporation (SADE). Its owner was a former Italian minister during World War II. Although the government collapsed after the war, he started the project with the help of new governments.

Wyong Dam / wikimedia

Protests by experts

 The slope of Mount Tok, which borders the reservoir, is a landslide area in the past. Although the locals warned the construction engineers and geologists about the dam’s construction, they did not pay much attention. In 1959, two years after the dam’s construction began, environmentalists told authorities that the project was dangerous because of cracks and crevices in the surrounding roads and that their investigations confirmed the instability of the dam, but they were ignored.

During the dam construction, an article was published in a local newspaper stating that landslides could occur again near the dam site and that there would be a catastrophe. This caused a stir among the area’s people, but the government later took legal action against the newspaper for “spreading false news and disturbing the peace.” The builders of the dam claimed the safety of the people, but people who did not believe in the stability of Mount Montek also called it a “walking mountain.”

Wyong reservoir filled with water / timermagazine

In 1960 the filling river basin had begun, and by that time, the government had taken over the dam. There were minor landslides and earthquakes in the surrounding area during this time. The first flood filled up to 600 feet, and after filling the reservoir, a large crack appeared in the section above the reservoir on Mount Tok. Many at the time realized that this was not a good sign. Then, on November 4, 1960, a landslide of about one million cubic meters [100 m] reached the reservoir. This caused a 7 feet high wave on the reservoir’s surface, but no one was injured.

Mount Tok / smithsonianchannel

Water seeps into nearby mountains by filling a reservoir and absorbing the water. Moisture on the surface of the hill eventually causes the soil to loosen. This is what happened in the vicinity of Mount Tok. Therefore, from November to December, the engineers lowered the water level to 450 feet. Construction of a tunnel to connect the upper and lower reaches of the reservoir was also completed in October 1961. This is to prevent the two areas from separating in the event of a sudden landslide. At the same time, equipment including pressure gauges and exploration wells were installed to monitor the stability of the mountain.

Part of the mountain first landslide / smithsonianchannel

The catastrophe

With heavy rains in November 1962, the water level in the reservoir rose again to 780 feet. As a result of this event, the surrounding mountains move 0.5 inches per day towards the reservoir. The engineers then work to lower the water level in the reservoir again. Due to the rainfall in the summer of 1963, the water level reached a maximum of 814 feet. Then the magnitude of the movement is 1.2 inches per day. On October 4, 1963, it increased to 8 inches per day. As a result, the mayor of longarone has ordered residents to evacuate. But reservoir engineers and SADE said there was no problem with doing so.

On the night of October 9, 1963, water recorded the water level in the reservoir at 782 feet. The water level was about 80 feet below the top edge of the dam. Residents of the lower village have been warned that a significant landslide will occur on that day and that Protests will form a large wave of up to 20 miles per hour due to the landslides and that the water will come down slightly above the dam. Although a landslide occurred as expected, it was the worst of all calculations.

How the waves traveled in two directions due to landslides / smithsonianchannel

At ten o’clock in the morning of October 9, 1963, the dam’s engineers saw Mount Monty Tok rapidly descending with trees and rocks. The landslide was a massive mound about 1.5 miles long and about a mile deep. The mound was about 260,000,000 cubic feet [260,000,000 m], almost twice the reservoir’s maximum capacity! Within 45 seconds, the river basin was wholly filled with mud and mud at speeds of up to 60 miles [60 km] an hour, and the water that had accumulated reached 50,000,000 cubic feet [820 m], and two tidal waves pounded the lower villages. The village of Irato, above the reservoir, miraculously survived the onslaught of waves. The waves, which were about 330 feet [330 m] above the dam’s mouth, caused nearly 275 million tons of water to flow out of the dam. The floodwaters receded into the city of longarone, where about 5,000 villagers were expected to flee. Instead, the five villages below were completely submerged.

What the city of Longaron looked like before and after the destruction of Wyong / interestingengineering

The extent of the devastation

The waves destroyed about 80% of the city of longarone. Of the city’s 372 buildings, only 22 remain. Waves covered everything else with mud and rocks. The tidal wave killed 1910 city dwellers. In addition, waves destroyed members of 350 families.

When the water came over the dam and hit the ground, it created a vast atmosphere, which was more explosive than the atmosphere created when the Hiroshima atomic bomb exploded. As a result, many of the bodies were found naked. The explosion in the air hole had even stripped people of their clothes.

Twelve-year-old Michele Colette, a survivor of the incident, said in a statement that a large hole had formed beneath her body and that she felt as if she were being pulled over by a sleeping bed. She further says that she was stuck. It was only then that the body of water reached the area where it was. She had first heard it as a lot of iron was rolling towards her.

Surprisingly, no significant damage was caused by this catastrophe except for minor damage to the upper part of the dam. There were no explosions on the dam, mainly due to the gas explosion. It still stands above the city of longarone. But today, it is not used as a reservoir. Instead, a new pumping system was added to the Wyong Basin from the disaster site to help keep the lake water constant. The dam bypass tunnel has also been extended. This allows water to flow safely into Pia’s river valley. longarone and other villages in the Prev Valley were rebuilt, and many of the survivors of the Wyong Dam disaster were resettled in the newly built village of Wyong.

Wyong Dam as it looks today /

After the accident, the government tried to ignore it, defining it as a “natural disaster.” However, a trial was held due to continuous pressure from the Communist Party and the media. Despite the ruling against SADE and several CEB engineers, the Italian government did not file a lawsuit against SADE.

Today, longarone Village has only one memorial church built to commemorate the disaster. The church is located near the Wyong Dam. Its interior is somewhat similar to a dam, and it also has concrete walls that are remarkably sloping. Part of the dam has been open to the public since 2002.

Church built to commemorate the Wyong disaster / wikipedia

In 2008, UNESCO named the Wyong disaster one of the world’s most significant man-made disasters. Today, the Wyong Dam reminds us of the devastation caused by ignoring even the slightest warning sign in large-scale engineering projects.