Contra Dam
{{Infobox dam
| name = Contra Dam
| image = BarrageDeContra.JPG
| image_caption = Contra Dam
| name_official = Contra Dam
| dam_crosses = Verzasca River
| location = Ticino, Switzerland
| dam_type = Arch dam
| dam_length = {{Convert|380|m|ft|abbr=on}}
| dam_height = {{Convert|220|m|ft|abbr=on}}
| plant_hydraulic_head = {{Convert|277|m|ft|abbr=on}} (Max)
| dam_width_base = {{Convert|25|m|ft|abbr=on}}
| dam_width_crest = {{Convert|7|m|ft|abbr=on}}
| dam_volume = {{Convert|660000|m3|ft3|abbr=on}}
| spillway_type = Service, uncontrolled overflow
| spillway_capacity = {{Convert|2150|m3/s|ft3/s|abbr=on}}
| construction_began = 1961
| opening = 1965
| cost =
| owner = Verzasca SA
| res_name = Lago di Vogorno
| res_capacity_total = {{Convert|105000000|m3|acre.ft|abbr=on}}
| res_catchment = {{Convert|230|km2|sqmi|abbr=on}}
| res_surface = {{Convert|160|ha|acre|abbr=on}}{{cite web|title=Contra Dam|url=http://www.swissdams.ch/swisscod/Dams/damForm/default.asp?ID=4|publisher=Swiss Committee on Large Dams|accessdate=21 October 2010|archive-url=https://web.archive.org/web/20081003022320/http://www.swissdams.ch/swisscod/Dams/damForm/default.asp?ID=4|archive-date=3 October 2008|url-status=dead}}
| res_max_depth =
| plant_operator =
| plant_turbines = 3 × 35 MW Francis-type
| plant_capacity = 105 MW
| plant_annual_gen = 234 GWh
| plant_commission =
| plant_decommission =
| location_map = Switzerland
| location_map_caption =
| location_map_size =
| coordinates = {{coord|46|11|48|N|8|50|52|E|type:landmark|display=inline,title}}
| website =
| extra =
}}
File:Aerial imagery of Contra Dam and Verzasca River, Ticino, Switzerland.webm
The Contra Dam, commonly known as the Verzasca Dam and the Locarno Dam,{{cite web|title=007's bungee jump tops best movie stunt poll|url=http://www.breakingnews.ie/archives/2002/1117/entertainment/qlqlkfmhgb/|publisher=BreakingNews.ie|accessdate=24 October 2010|date=November 17, 2002|archive-date=14 June 2011|archive-url=https://web.archive.org/web/20110614045937/http://www.breakingnews.ie/archives/2002/1117/entertainment/qlqlkfmhgb/|url-status=dead}} is an arch dam on the Verzasca River in the Val Verzasca of Ticino, Switzerland. The dam creates Lago di Vogorno {{Convert|2|km|mi|abbr=on}} upstream of Lake Maggiore and supports the 105 MW Verzasca 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.{{cite web|title=Dams in Switzerland|url=http://www.swissdams.ch/index.php/en/swiss-dams/dams-in-switzerland|publisher=Swiss Committee on Dams|accessdate=17 March 2017|archive-date=1 April 2017|archive-url=https://web.archive.org/web/20170401153133/http://www.swissdams.ch/index.php/en/swiss-dams/dams-in-switzerland|url-status=dead}}
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.{{cite news|url=https://www.thetimes.com/culture/film/article/for-a-glad-moment-i-was-flying-then-i-bombed-0ph3b8tprcg|title=For a glad moment I was flying ... then I bombed|author=Matt Munday|publisher=The Sunday Times|date=12 November 2006|access-date=2010-11-01}}
Background
On May 6, 1960, Verzasca SA was formed to construct the dam as the center-piece of the Verzasca Hydroelectric Complex.{{cite web|title=Verzasca SA, 50 years of energy|url=http://www.cdt.ch/ticino-e-regioni/cronaca/24070/verzasca-sa-50-anni-di-energia.html|publisher=Corriere de Ticino|accessdate=24 October 2010|language=Italian|date=May 6, 2010|archive-url=https://web.archive.org/web/20100509081917/http://www.cdt.ch/ticino-e-regioni/cronaca/24070/verzasca-sa-50-anni-di-energia.html|archive-date=9 May 2010|url-status=dead}} Construction of 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 {{Convert|200|m3/s|ft3/s|abbr=on}} capacity. As the river can have flows much higher than the tunnel's capacity, this was accepted as a risk by engineers.{{cite web|last=Giovanni Lombardo|first=Henry Gicot|title=Some New Arch Dams in Switzerland and Austria|url=http://www.lombardi.ch/publications/pdfviewer.php?ID=32|publisher=The Japan Dam Association|accessdate=24 October 2010|date=November 1967|archive-url=https://web.archive.org/web/20110707000138/http://www.lombardi.ch/publications/pdfviewer.php?ID=32|archive-date=7 July 2011|url-status=dead}} Excavation of the right side of the dam had to be expanded due to unforeseen weathered rock and designs were altered within 15 days.
File:ETH-BIB-Verzasca-Staumauer-LBS H1-025325.tif
Concrete pouring and placement occurred for 18 months, of which the maximum poured in a day was {{Convert|3100|m3|ft3|abbr=on}} and in a month, {{Convert|55000|m3|ft3|abbr=on}}. The aggregate for the concrete was obtained from a quarry near the construction site. The high-quality and strength gneiss-rock was ground in a rotary crusher and prepared in the concrete mixture. To facilitate the contraction and settling of the concrete in the dam, it was cooled with a series of steel pipes that ran throughout the mass of concrete, with the exception of the top {{Convert|30|m|ft|abbr=on}} of the dam. A grout curtain was placed around and below the dam as well to prevent leakage, which consumed a large amount of cement. In August 1964, the reservoir began to fill{{cite web |first1=HARSH K. |last1=GUPTA |first2=B. K. |last2=RASTOGI |first3=HARI |last3=NARAIN |title=Common features of the reservoir-associated seismic activities |url=http://www.bssaonline.org/cgi/content/abstract/62/2/481 |publisher=Bulletin of the Seismological Society of America |accessdate=24 October 2010 |date=April 1972 |archive-date=13 June 2010 |archive-url=https://web.archive.org/web/20100613141940/http://www.bssaonline.org/cgi/content/abstract/62/2/481 |url-status=dead}} and in September 1965, the reservoir was full and the dam completed.
=Seismic activity=
During what Dr. Giovanni Lombardi, the dam's designer, described as an "exceptionally rapid rise of water during the first filling" of the reservoir, beginning in August 1964, there were seismic shocks. The earthquakes began in May 1965 and the biggest shocks had occurred later in October and November after the reservoir was full. The epicenters were located at two faults near the dam.{{cite book|author1=Joint Panel on Problems Concerning Seismology and Rock Mechanics |author2=National Academy of Sciences (U.S.) |author3=National Academy of Engineering |author4=National Research Council (U.S.). Division of Earth Sciences|title=Earthquakes related to reservoir filling|year=1972|publisher=National Academies|url=https://archive.org/details/bub_gb_EzUrAAAAYAAJ|quote=contra dam switzerland earthquake -costa. |page=[https://archive.org/details/bub_gb_EzUrAAAAYAAJ/page/n20 14]}}{{cite journal | last1=Ambraseys | first1=N. N. | last2=Sarma | first2=S. K. | title=Large Earthquake Forces on Gravity Dam | journal=Nature | volume=219 | issue=5161 | date=1968 | issn=1476-4687 | doi=10.1038/2191354a0 | pages=1354–1356 | bibcode=1968Natur.219.1354A | url=http://www.nature.com/nature/journal/v219/n5161/abs/2191354a0.html| url-access=subscription }} As many as 25 shocks occurred a day. The shocks stopped once the reservoir was emptied{{cite web|first=R. D.|last=Adams|title=Seismic effects at Mangla Dam: Pakistan|url=http://unesdoc.unesco.org/images/0000/000085/008521eb.pdf|publisher=UNESCO|accessdate=24 October 2010|page=5|date=January 1968|archive-date=7 August 2011|archive-url=https://web.archive.org/web/20110807132048/http://unesdoc.unesco.org/images/0000/000085/008521eb.pdf|url-status=live}} and no damage was found.{{cite book|last=Pedro|first=Jose Oliveria|title=Arch dams: designing and monitoring for safety|year=1999|publisher=International Centre for Mechanical Sciences|isbn=978-3-211-83149-6|page=371|url=https://books.google.com/books?id=YNDdD7DaqwYC&q=Contra+dam+seismic&pg=PA371|access-date=2020-11-26|archive-date=2023-12-28|archive-url=https://web.archive.org/web/20231228163615/https://books.google.com/books?id=YNDdD7DaqwYC&q=Contra+dam+seismic&pg=PA371#v=snippet&q=Contra%20dam%20seismic&f=false|url-status=live}} After refilling, the shocks decreased and an "equilibrium" was believed to have been reached, one that did not respond to variations in water load. Another large shock occurred several years after filling.{{cite journal | last1=Lane | first1=Rgt | last2=Fowler | first2=Jcw | last3=Willmore | first3=Pl | last4=Ghadery | first4=Mm | last5=Armstrong | first5=L | last6=Ambraseys | first6=Nn | last7=Allen | first7=Ac | last8=Haigh | first8=Ip | last9=Haws | first9=Et | last10=Little | first10=Al | last11=Long | first11=Re | last12=Howells | first12=Da | last13=Maddrell | first13=Rj | last14=Lancaster Jones | first14=P | title=Discussion. Seismic Activity at Man-Made Reservoirs | journal=Proceedings of the Institution of Civil Engineers | volume=51 | issue=4 | date=1972 | issn=1753-7789 | doi=10.1680/iicep.1972.5744 | pages=767–784|doi-access=free|display-authors=3}} By 1971, there were no more seismic shocks around the dam or reservoir. No known detailed geological studies were conducted prior to construction of the dam and several faults are known to exist in the area.
Specifications
=Dam=
The Contra Dam is a concrete slender arch dam with a height of {{Convert|220|m|ft|abbr=on}} and crest length of
{{Convert|380|m|ft|abbr=on}}. The dam is {{Convert|25|m|ft|abbr=on}} wide at its base and {{Convert|7|m|ft|abbr=on}} wide at its crest. The dam structure contains {{Convert|660000|m3|ft3|abbr=on}} of concrete and the structure itself has a surface area of {{Convert|44500|m2|ft2|abbr=on}}. The dam is slender in design and its horizontal arches are in an elliptical shape. The horizontal curvature of the dam decreases from the center of the dam towards its abutments and the curvature from the center of the arches increases from the crest down to the foundation. The thickness is constant with the exception of where the dam is received by its abutments; here it is thicker to reduce pressure on the rock, which can accept pressure of {{convert |70 |kg/cm2 |abbr=on}}. Vertically, the thickness of the dam increases from the crest down to the foundation and has a slight curve from the center towards the crest. This helps alleviate tensile stress for when the reservoir is not only full but empty. The dam's outlet works consist of two discharge pipes, capable of releasing up to {{Convert|170|m3/s|ft3/s|abbr=on}} each. One discharges into the original diversion tunnel and another is located at the base of the dam and discharges into the river valley below.
The dam creates Lago di Vogorno which has a {{Convert|105000000|m3|ft3|abbr=on}} capacity and surface area of {{Convert|160|ha|acre|abbr=on}}, collected from a catchment area of {{Convert|230|km2|sqmi|abbr=on}}. The Verzasca River has very irregular seasonal flows which can reach as high as {{Convert|1000|m3/s|ft3/s|abbr=on}}.
Lombardi considers it one of his most aesthetically pleasing dams, primarily because of the slenderness of the concrete arch and the "outstanding cleanness of the design." The design also reduced the amount of concrete needed, therefore reducing the cost as well.{{cite news|url=http://www.waterpowermagazine.com/storyprint.asp?sc=1692|title=Roll of honour|date=9 July 1999|publisher=Water Power Magazine|accessdate=2007-05-24|archive-url=https://web.archive.org/web/20110614045623/http://www.waterpowermagazine.com/storyprint.asp?sc=1692|archive-date=14 June 2011|url-status=dead}}
=Spillways=
File:Valle Verzasca Staumauer.jpg
The dam has two spillways, each located on the structure, near its abutments on either side which have a maximum discharge capacity of {{Convert|2150|m3/s|ft3/s|abbr=on}}.[https://www.swissdams.ch/de/les-barrages/liste-des-barrages-suisses/Contra.pdf Portrait of Contra Dam] Schweizerisches Talsperrenkomitee, retrieved 14 June 2024. Each spillway contains six fixed-crest weirs that are {{Convert|12|m|ft|abbr=on}} wide. From each opening, the water flows down a single chute to a flip bucket at the bottom of the spillway. The flip buckets dissipate and deflect the water towards the center axis of the valley {{Convert|200|m|ft|abbr=on}} below. The spillways were later modified to improve releases and function by increasing the size of the piers and adding additional lateral deflectors near the crest.{{cite web|last=P.F. Bertola|first=R. Bremen|title=Increasing the Spillway Capacity at Contra Dam|url=http://www.lombardi.ch/publications/pdfviewer.php?ID=48|publisher=Lombardi Engineering Inc.|accessdate=24 October 2010|archive-url=https://web.archive.org/web/20110706235940/http://www.lombardi.ch/publications/pdfviewer.php?ID=48|archive-date=6 July 2011|url-status=dead}}
=Power plant=
The dam supports a 105 MW power station that contains 3 × 35 MW Francis turbines and generates an average of 234 GWh annually. Water from the reservoir at {{Convert|470|m|ft|abbr=on}} above sea level is transferred to an underground power station downstream at {{Convert|193|m|ft|abbr=on}} above sea level, affording a maximum hydraulic head of {{Convert|277|m|ft|abbr=on}}.{{cite web|title=Partecipanzione Verzasca|url=http://www.aet.ch/index/attivita/produzione/partecipazioni_produttive/partecipazione_verzasca.htm|publisher=Azienda Elettrica Ticinese|accessdate=24 October 2010|language=Italian|archive-url=https://web.archive.org/web/20110706221601/http://www.aet.ch/index/attivita/produzione/partecipazioni_produttive/partecipazione_verzasca.htm|archive-date=6 July 2011|url-status=dead}} The power plant can discharge up to {{Convert|50|m3/s|ft3/s|abbr=on}} of water which exits via a {{Convert|1.9|km|mi|abbr=on}} tailrace tunnel into Lago di Verbano. The builder and owner is Verzasca SA; which has an 80-year concession on the power station which will expire in 2046.{{cite web|url=http://www.ail.ch/index/ail-home/ail-cenni_storici.htm|title=AIL - Aziende Industriali di Lugano SA - Cenni storici|language=Italian|accessdate=2007-05-24|archive-url=https://web.archive.org/web/20070930031700/http://www.ail.ch/index/ail-home/ail-cenni_storici.htm|archive-date=2007-09-30|url-status=dead}}
In popular culture
{{See also|GoldenEye}}
The opening scene of the 1995 James Bond film GoldenEye featured Bond jumping off the dam. The stunt was performed by British stuntman Wayne Michaels. The jump was voted as best movie stunt of all time in a 2002 Sky Movies poll. The dam doubled as the fictional Arkhangelsk Chemical Weapons Facility located in the northern Soviet Union during the Cold War. It is spelled "Arkangel" in the film.
The dam owners started to lease access to the dam, soon after GoldenEye was released, to a commercial bungee jump operator. According to the operator, over 10,000 people have jumped the 220 m (720 ft) from the dam.
Contestants bungee jumped off the dam as a Roadblock task in the first episode of the 14th season of The Amazing Race and the fifth episode of the 33rd season.{{cite web|url=http://www.tvguide.com/detail/tv-show.aspx?tvobjectid=296519&more=ucepisodelist&episodeid=9978144|title=Amazing Race 14|publisher=TV Guide|accessdate=2009-02-08|archive-date=2009-02-19|archive-url=https://web.archive.org/web/20090219160537/http://www.tvguide.com/detail/tv-show.aspx?tvobjectid=296519&more=ucepisodelist&episodeid=9978144|url-status=live}}
The climax scene of the Indian Bollywood movie Dhoom 3 was shot at this dam.{{cite news|url=http://www.thedailybeast.com/articles/2013/12/31/dhoom-3-review-bollywood-s-baffling-blockbuster.html|title='Dhoom 3' Review: Bollywood's Baffling Blockbuster|work=thedailybeast.com|date=31 December 2013|access-date=31 December 2013|archive-date=29 June 2015|archive-url=https://web.archive.org/web/20150629115523/http://www.thedailybeast.com/articles/2013/12/31/dhoom-3-review-bollywood-s-baffling-blockbuster.html|url-status=live}}
In October 2022, an artificial climbing wall built on the dam hosted an event called Red Bull Dual Ascent, the first competition climbing event in a multi-pitch format.{{cite web |last=Miller |first=Delaney |date=2 November 2022 |title=Yep: There was a 600-foot Multipitch Race up a Swiss Dam |url=https://www.climbing.com/competition/red-bull-dual-ascent/ |accessdate=9 March 2024 |magazine=Climbing}}
Notes and references
{{Reflist|30em}}
External links
{{stack|{{Portal|Switzerland|Water|Renewable energy}}}}
{{commons category}}
- [https://web.archive.org/web/20070927005148/http://www.swissdams.ch/Dams/damForm/default_e.asp?ID=4 Dam profile] - Swiss Committee on Dams
- {{Structurae|id=20007410|title=Contra Dam}}
- [http://www.bondpix.com/bungee_jumping.htm Bungee jumping at the dam] (photographs and video)
- [http://www.trekking.ch/eng/bungy.asp Trekking-Team] {{Webarchive|url=https://web.archive.org/web/20070523171702/http://www.trekking.ch/eng/bungy.asp |date=2007-05-23}}, bungy operator at the dam
- [http://intrepidearth.net/human-structures-non-building/the-james-bond-goldeneye-dam-verzasca-dam/ Intrepid Earth] {{Webarchive|url=https://web.archive.org/web/20110818150837/http://intrepidearth.net/human-structures-non-building/the-james-bond-goldeneye-dam-verzasca-dam/ |date=2011-08-18}} Verzasca Dam
Category:Buildings and structures in Ticino
Category:Hydroelectric power stations in Switzerland
Category:Dams completed in 1965
Category:1965 establishments in Switzerland
Category:Energy infrastructure completed in 1965