Arch dam
Encyclopedia
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
that is curved and commonly built with concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes into its foundation or abutments. An arch dam is most suitable for narrow gorge
Canyon
A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...
s or canyon
Canyon
A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...
s with steep walls of stable rock to support the structure and stresses. Since they are thinner than any other dam type, they require much less construction material, making them economical and practical in remote areas. The development of arch dams throughout history began with the Romans
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
in the 1st century BC and after several designs and techniques were developed, relative uniformity was achieved in the 20th century.
History
The first known arch dam, the Glanum DamGlanum Dam
The Glanum Dam, also known as the Vallon de Baume dam, was a Roman arch dam built to supply water to the Roman town of Glanum, the remains of which stand outside the town of Saint-Rémy-de-Provence in south-west France. It was situated south of Glanum, in a gorge that cut into the hills of Les...
, also known as the Vallon de Baume Dam, was built by the Romans
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and it dates back to the 1st century BC. The dam was about 12m high and 18m in length. Its radius was about 14m and it consisted of two masonry walls. The Romans built it to supply nearby Glanum
Glanum
Glanum was an oppidum, or fortified town, founded by a Celto-Ligurian people called the Salyens in the 6th century B.C.,. It was known for the healing power of its spring. It became a Roman city in Provence until its abandonment in 260 A.D....
with water.
The Monte Novo Dam in Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
was another early arch dam built by the Romans in 300 AD. It was 5.7m high and 52m long with a radius of 19m. The curved ends of the dam met with two winged walls that were later supported by two buttresses. The dam also contained two water outlets to drive mills downstream.
The Dara Dam
Dara Dam
The Dara Dam was a Roman arch dam at Dara in Mesopotamia , a rare pre-modern example of this dam type. The modern identification of its site is uncertain, but may rather point to a common gravity dam.- Ancient account :...
was another arch dam built by the Romans in which the historian Procopius
Procopius
Procopius of Caesarea was a prominent Byzantine scholar from Palestine. Accompanying the general Belisarius in the wars of the Emperor Justinian I, he became the principal historian of the 6th century, writing the Wars of Justinian, the Buildings of Justinian and the celebrated Secret History...
would write of its design: "This barrier was not built in a straight line, but was bent into the shape of a crescent, so that the curve, by lying against the current of the river, might be able to offer still more resistance to the force of the stream."
The Mongolians also built arch dams in modern-day Iran. Their earliest was the Kebar Dam
Kebar Dam
The Kebar Dam is a masonry arch dam on the Kebar River, located 23 km southeast of Qom, Iran near the village of Khowrabad. The dam is an early arch dam and was the first arch dam constructed by the Mongolians, around 1300 AD. The dam is 26m tall and 55m wide and was constructed for irrigation...
built around 1300, which was 26 m high and 55 m long, and had a radius of 35 m. Their second dam was built around 1350 and is called the Kurit Dam
Kurit Dam
The Kurit Dam is a masonry arch dam located 34 km southeast of Tabas, Iran near the village of Kurit. The dam is an early arch dam constructed by the Mongolians around 1350 AD. The dam was originally 60m tall but 4m of height was added in 1850. The dam was constructed in a very narrow gorge and was...
. After 4 m was added to the dam in 1850, it became 64 m tall and remained the tallest dam in the world until the early 20th century. The Kurit Dam was of masonry design and built in a very narrow canyon. The canyon was so narrow that its crest length is only 44% of its height. The dam is still erect, even though part of its lower downstream face fell off.
The Elche Dam in Elche, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
was a post-medieval arch dam built in the 1630s by Joanes del Temple and the first in Europe since the Romans. The dam was 26 m high and 75 m long, and had a radius of 62 m. This arch dam also rest on winged walls that served as abutments.
In the 20th century, the world's first variable-radius arch dam was built on the Salmon Creek
Salmon Creek Dam
The Salmon Creek Dam is a concrete arch dam on the Salmon Creek, northwest of Juneau, Alaska. Built in 1914, it is the world's first constant-angle arch variable radius dam. Since it was built, over 100 such dams have been constructed all over the world....
near Juneau, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. The Salmon Creek Dam's upstream face bulged upstream, which relieved pressure on the stronger, curved lower arches near the abutments. The dam also had a larger toe, which off-set pressure on the upstream heel of the dam, which now curved more downstream. The technology and economical benefits of the Salmon Creek Dam allowed for larger and taller dam designs. The dam was, therefore, revolutionary, and similar designs were soon adopted around the world in particular by the U.S. Bureau of Reclamation.
Morrow Point Dam
Morrow Point Dam is a concrete double-arch dam on the Gunnison River located in Colorado, the first dam of its type built by the U.S. Bureau of Reclamation. Located in the upper Black Canyon of the Gunnison, it creates Morrow Point Reservoir, and is within the National Park Service-operated...
in Colorado. By the late 20th century, arch dam design reached a relative uniformity in design around the world. Currently, the tallest and largest arch dam in the world is the 292 m Xiaowan Dam
Xiaowan Dam
The Xiaowan Dam is a large hydroelectric arch dam on the Lancang River in Yunnan Province, southwest China. It is the world's highest arch dam and will be the second largest hydroelectric power station in China after the Three Gorges Dam. Construction started on 1 January 2002. The river was...
in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, which was completed in 2010. The longest multiple arch with buttress dam in the world is the Daniel-Johnson Dam
Daniel-Johnson Dam
The Daniel-Johnson Dam , formerly known as Manic-5, is a multiple arch buttress dam on the Manicouagan River which creates Manicouagan Reservoir. The dam is composed of 14 buttresses and 13 arches and is north of Baie-Comeau in Quebec, Canada...
in Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. It is 214 meters high and 1,314 meters long across its crest. It was completed in 1968 and put in service in 1970. China is currently constructing the Jinping 1 Dam in Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
, which when complete will be world's tallest arch dam at 305m.
Design
Arch dams require a high level of stress and force analysis in order to create a sufficient design. The main force against an arch dam is the hydrostatic pressure provided by the reservoir behind it, uplift, which is water pressure beneath the dam, the weight of the dam itself, and all the forces combined. Other forces that affect a dam include, but are not limited to, temperature, chemical reactions, settling, silt accumulation, and earthquakes.Most often, the arch dam is made of concrete and placed in a "V"-shaped valley. The foundation or abutments for an arch dam must be very stable and proportionate to the concrete. There are two basic designs for an arch dam: constant-radius dams, which have constant radius of curvature, and variable-radius dams, which have both upstream and downstream curves that systematically decrease in radius below the crest. A dam that is double-curved in both its horizontal and vertical planes may be called a dome dam. Arch dams with more than one contiguous arch or plane are described as multiple-arch dams. Early examples include the Roman Esparragalejo Dam
Esparragalejo Dam
The Esparragalejo Dam was a Roman multiple arch buttress dam at Esparragalejo, Badajoz province, Extremadura, Spain. Dating to the 1st century AD, it is the earliest known dam of its kind....
and Muro Dam
Muro Dam
The Muro Dam was a Roman dam in Portugal. Located near the eastern municipality of Campo Maior, it is the largest surviving ancient dam in the country south of the Tagus river....
with later examples such as the Daniel-Johnson Dam (1968) and Itaipu Dam (1982). At an increased cost, an arch dam can have steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
rods or pre-stressed steel cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...
reinforcements and therefore require less concrete than does a gravity dam or arch-gravity dam
Arch-gravity dam
An arch-gravity dam, curved-gravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. It is a dam that curves upstream in a narrowing curve that directs most of the water against the canyon rock walls, providing the force to compress the dam...
. As arch dams are commonly constructed in remote mountainous areas, less material is beneficial when it has to be delivered with difficulty to the site.
However, as a result of the failure of the Gleno Dam
Gleno Dam
The Gleno Dam was a multiple-arch dam on the Gleno River in the Valle di Scalve in the northern Province of Bergamo, Italy. The dam was constructed between 1916 and 1923 with the purpose of producing hydroelectric power...
shortly after it was constructed in 1923, the construction of new multiple arch dams has become less popular.
In general, arch dams are classified as thin, medium, or thick. If width of an arch dam's base is 2/10 of the dam's height or less, it is thin. Any base and height ratio greater than 2/10 but less than 3/10 is considered medium. Thick is a ratio of 3/10 or greater. In addition, an arch dam's base is historically just as thick as the crest, but often it is twice as thick as the crest. Contraction joints are normally placed every 20 m in the arch dam and are later filled with grout
Grout
Grout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints . Grout is generally composed of a mixture of water, cement, sand, often color tint, and sometimes fine gravel...
after the control cools and cures.
Examples of arch dams
- Inguri DamInguri DamThe Inguri Dam is a hydroelectric dam on the Inguri River in Georgia. Currently it is the world's highest concrete arch dam with a height of . It is located north of the town Jvari...
- Buchanan DamBuchanan DamThe Buchanan Dam is a multiple arch dam located on the Colorado River of Texas.-Description:The dam forms Lake Buchanan and was the first dam to be completed in the chain of Texas Highland Lakes...
(example of Multiple-Arch type) - Glen Canyon DamGlen Canyon DamGlen Canyon Dam is a concrete arch dam on the Colorado River in northern Arizona in the United States, just north of Page. The dam was built to provide hydroelectricity and flow regulation from the upper Colorado River Basin to the lower. Its reservoir is called Lake Powell, and is the second...
- Hoover DamHoover DamHoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada. It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President...
- Idukki DamIdukki DamThe Idukki Dam, located in Kerala, India, is a 555 foot tall arch dam. The dam stands between the two mountains - Kuravanmala m and Kurathimala m. It was constructed and is owned by the Kerala State Electricity Board....
- Karun-3 damKarun-3 damThe Karun-3 dam is a hydroelectric dam on the Karun river in the province of Khuzestan, Iran. It was built to help meet Iran's energy demands as well as to provide flood control. The Karun has the highest discharge of Iran's rivers....
- Daniel-Johnson DamDaniel-Johnson DamThe Daniel-Johnson Dam , formerly known as Manic-5, is a multiple arch buttress dam on the Manicouagan River which creates Manicouagan Reservoir. The dam is composed of 14 buttresses and 13 arches and is north of Baie-Comeau in Quebec, Canada...
- Pensacola DamPensacola DamThe Pensacola Dam, also known as the Grand River Dam, is a multiple-arch buttress dam on the Grand River in-between Disney and Langley in the U.S. state of Oklahoma. The dam is operated by the Grand River Dam Authority and creates Grand Lake o' the Cherokees...
(longest Multiple-Arch type) - Victoria DamVictoria Dam (Sri Lanka)Victoria Dam is an arch dam located upstream of the Mahaweli River's mouth and from Teldeniya. Its main purposes are irrigation and hydroelectric power production. It is the tallest dam in Sri Lanka, and supports a power station, the largest hydroelectric power station in the country...