Contra Dam

Geschichte

The Contra Dam, commonly known as the Verzasca Dam and the Locarno Dam, is an arch dam on the Verzasca River in the Val Verzasca of Ticino, Switzerland. The dam creates Lago di Vogorno 2km upstream of Lake Maggiore and supports the 105 MW Verzasca Hydroelectric Power Station hydroelectric power station. It was constructed between 1961 and 1965 and starting shortly after its reservoir was filled, a series of earthquakes related to its water load occurred until 1971. The dam is owned and operated by Verzasca SA and is the fourth tallest in Switzerland.The dam became a popular bungee jumping venue after a James Bond stuntman jumped off it in the opening scene of the 1995 film GoldenEye; a stunt voted as the best movie stunt of all time in a 2002 Sky Movies poll.BackgroundOn May 6, 1960, Verzasca SA was formed to construct the dam as the center-piece of the Verzasca Hydroelectric Complex. Construction in the dam began in 1961. The dam was designed and its construction supervised by Lombardi & Gellaro Ltd. Because the Contra Dam is at a lower elevation compared to other Swiss dams, warmer weather allowed construction to be carried out year-round. To divert the river and prepare a dry work-site for the dam, cofferdams were constructed, one of which redirected the river through a diversion tunnel with a 200m3/s capacity. As the river can have flows much higher than the tunnel's capacity, this was accepted as a risk by engineers. Excavation of the right side of the dam had to be expanded due to unforeseen weathered rock and designs were altered within 15 days.