Famous Dams Of The World
A dam is said to be a barrier that confines water. Dams generally are used to retain water, while other structures such as dikes are used to manage or prevent water flow into a region.
Dams are combined with Hydropower and pumped-storage to provide electricity for millions of consumers. It can also be used to collect water or for storage of water while some dams are also built for recreational purposes. One the basis of size dams can be of following types:
- Masonry and concrete dams
- Embankment dams
- Cofferdams
- Beaver dams
With the types discussed here are some of the most famous dams in the world:
The Hoover Dam.
The Hoover Dam, USA
This dam was considered to be a masterpiece of the twentieth century when it was built in 1936.
The Dam is built on the mighty Colorado River. It is an arch-gravity type dam.
Presently it is considered the most famous dam in the world.
It is 221m high and its base is 200m thick.
It was named after President Hoover who played a vital role in its construction.
It is considered a national historic landmark in the United States since 1985.
Different Types Of Dams
- Types Of Dams
A dam is a barrier built across a water course to hold back or control the water flow. Some dams divert the flow of river water into a pipeline, canal, or channel.
The Grand Dixence Dam.
Grande Dixence, Switzerland
The Grande Dixence Dam is built in the canton of Valais in Switzerland.
Its construction started in 1953 and was completed in 1965.
It 285 meters high and is the tallest gravity dam in the world. The dam is used to produce hydroelectricity and stores up to 100 Billion gals of water.
The Dworshak Dam.
Dworshak Dam, USA
Dworshak Dam is a dam built on the Clearwater River. It is hydroelectric, concrete gravity dam providing up to 460 MW of power generation.
The dam is the highest concrete dam in the American continent and the 22nd highest dam in the world. Its construction started in 1966 and was completed in 1973. Its height and length are 219m and 1,002m respectively.
Famous Bridges Of The World
- Bridges Of The World
Bridges, the idols of the engineering world, influence the cultural development, lifestyles and the environment in countless ways.
The Inguri Dam.
The Inguri Dam, Georgia
The Inguri Dam on the Inguri River is a hydroelectric dam in Georgia. Currently it is the world's highest concrete arch dam with a height of 272m.
It is located near the town Jvari.
Its construction started in 1961 and was completed in 1987. Its total power generation capacity is 1,320 MW.
The Vajont Dam.
Vajont Dam, Italy
The Vajont Dam is a disused dam. It was completed in 1959 in the valley of the VajontRiver. The dam caused the deaths of approximately 2,000 people in a landslide in 1963.
The dam is 262m high and 27m thick It is considered on of the worst dam tragedy caused by nature and engineering failure.
The Almendra Dam.
Almendra Dam, Spain
The Almendra Dam on the River Tormes in Salamanca, Spain is five kilometers from the village Almendra.The dam is used for Hydroelectricity.
Its construction started in 1964 and was completed in 1970. The dam is 202m high and stores 2.5 billion cubic meters of water. It is one of the tallest structures in whole of Spain.
The Three Gorges Dam.
The Itaipu Dam.
The Sayano-Shushenskaya Dam.
Three Gorges Dam, China
The Three Gorges Dam on the Yangtze River is a hydroelectric dam. It is the world's largest electricity-generating plant. The building of this dam was started in 1994 and completed in 2008.
It is 185m high and 2,335m long with a total power generation capacity of 22,500 MW and water storing capacity of 39.3 km3.
The dam’s cost is about $26 Billion. The dam is considered as an economic and engineering success for China.
Itaipu Dam, Brazil
The Itaipu Dam on the Parana River is a hydroelectric dam located on the border between Brazil and Paraguay.
The word Itaipu means "the sound of a stone". Its construction started in 1970 and was completed in 1984.
The dam is7,700m and 196m high. The dam’s total power generation is 14,000 MW.
The dams 90% energy is consumed by Paraguay while the remaining 10% is used by Brazil.
Sayano-Shushenskaya, Russia
Sayano–Shushenskaya hydroelectric power station on the Yenisei River is the world’s sixth largest hydroelectric plant.
Its construction was started in 1961 and was opened in 1978.
At 246m of height and 1,066m of length, the dam can carry up to 31.3 cubic km of water. Its total power generation is 6,400 MW.
The power house on this dam has suffered many accidents with the latest being in 2009 when it was closed and opened again in February 2010.
The Aswan Dam.
The Aswan Dam, Egypt
Although not as tall as many other dams, mentioned above, yet Aswan dam is one of the most famous and historic dams ever built. It is situated on the world's longest river i.e. River Nile.
The Aswan Dam is still one of the largest dams in the world, its history dates back to as early as the 1000s, when first attempts were made to built a dam at this site. However the present day structure started in 1898 and was completed in 1902.
The dam is 3,830 metres long and 980 metres at the base. It can pass upto 11,000 cubic metres of water. Its power generation capacity is upto 2,100 MW.
Types Of Dams
A dam is a barrier built across a water course to hold back or control the water flow. Some dams divert the flow of river water into a pipeline, canal, or channel. Others raise the level of inland waterways to make them navigable by ships and barges. Many dams harness the energy of falling water to generate electric power. Dams also hold water for drinking and crop irrigation, and provide flood control.
Classification of dams
According to their functions, dams serve three main purposes: storage, diversion, or detention.
Theyare constructed to impound water in periods of surplus supply for use in periods of deficiency. Many small dams impound the spring runoff for later use in dry summers. Storage dams may also provide a water supply, or improved habitat for fish and wildlife. They may store water for hydroelectric power generation, irrigation or for a flood control project
They provide sufficient pressure for pushing water into ditches, canals, or other conveyance systems. Such shorter dams are used for irrigation, and for diversion from a stream to a distant storage reservoir.
They minimize the effect of sudden floods and trap sediment.
They carry water discharge over their crests, and are made of materials that will not be eroded by such discharges. Non-overflow dams are designed not to be overtopped, and may include earth and rock in their structure. Often the two types are combined to form a composite structure.
Dam structure and design
Earthfill dams
The development of modern construction equipment has made massive earthfill dams economical. The Rogun and Nurek dams in Tajikistan, the world's highest, are earthfill structures. Canada's Syncrude Tailings, which will be the world's most massive, is also an earthfill structure.
Earthfill dams typically have a water-impermeable clay core, and a water cut-off wall from their base to bedrock to prevent underground seepage. During construction, the stream or river must be diverted either through the dam-site by means of a conduit, or around it by means of a tunnel.
Earthfill dams require supplementary structures as spillways for discharging water from behind the dam. If sufficient spillway capacity is not provided, an earthfill dam may be damaged or even destroyed by the erosive water flowing over its crest. Unless special precautions are taken, such dams are also subject to serious damage or even failure, due to water seepage.
Embankment or rockfill dams
The rockfill dam uses rock instead of earth to provide stability. It has an impervious, watertight membrane, usually an upstream facing of impervious soil, concrete paving, or steel plates; or it may have a thin interior core of impervious soil.
Rockfill embankment dams and zoned-embankment dams are the most common embankment dams. Rockfill embankment dams have a mound of loose rock covered with a waterproof layer on the upstream side. The waterproof layer may be made of concrete, flat stone panels, or other impervious materials. Zoned-embankment dams include an impervious core surrounded by a mound of material that water can penetrate. The supporting mound is usually made of loose rock or earth. The core might be built from concrete, steel, clay, or any impervious materials.
Embankment dams hold back water by the force of gravity acting upon their mass. Embankment dams require more material because loose rock and earth are less dense than concrete. Engineers often choose to build them if the materials are readily available. Our Tarbela Dam contains more than 126 million cubic metres earth and rock. This amounts to more than 15 times the volume of concrete used in the Grand Coulee Dam.
Gravity dams
Gravity dams hold back water only by the sheer force of their weight pushing downward. To do this, gravity dams must consist of a mass so heavy that the reservoir water cannot push the dam downstream or tip it over. They are much thicker at the base than the top. As water becomes deeper, it exerts more horizontal pressure on the dam. Gravity dams are relatively thin near the surface of the reservoir, where the water pressure is light. A thick base enables the dam to withstand more intense water pressure at the bottom of the reservoir.
Most gravity dams are made from concrete, a mixture of port land cement, water, and aggregates. Concrete is well suited for dam construction. A concrete gravity dam uses a triangular cross-section and steep upstream face. Its shape differs from that of the earthfill or rockfill dam in that its inward, water-facing side is perpendicular to the water surface; in profile, the dam forms a right-angled triangle.
The Grand Coulee Dam contains nearly 8 million cubic metres concrete. It is one of the most massive structures ever built, standing 168 metre high and 1,592 metre long.
Concrete Arch
Concrete arch dams are built in narrow, steep-walled canyons. The canyon walls take up the thrust exerted by the arch and the pressure of the water. Such dams can be extraordinarily thin. Vaiont Dam is 265 metres high, but only 22.7 metres thick at its base. In comparison, Hoover Dam is 221 metres high and 201 metres thick at its base and has a partial arch effect.
Glen Canyon Dam, which spans the Colorado River in Arizona, is the highest arch dam in the United States. It is 216 metres high and 475 metres long but contains less than four million cubic metres of concrete. Arch dams can be less expensive to build than gravity dams..
Buttress dam
A buttress dam consists of a face supported by several buttresses on the downstream side. Buttress dams are made of concrete reinforced with steel. Buttresses are typically spaced across the dam site every 6 to 30 metre, depending upon the size and design of the dam. Buttress dams are sometimes called hollow dams because the buttresses do not form a solid wall stretching across a river valley.
Buttress dams require less concrete than gravity dams, but are not necessarily less expensive to build. Costs associated with the complex work of forming the buttresses or multiple arches may offset the savings in construction materials. Buttress dams may be desirable, however, in locations with foundations that would not easily support the massive size and weight of gravity dams.
The entire nation of Pakistan one way or the other depends on the dams. The water stored in the dams is not only used for the agricultural purposes but also to provide electricity to a nation of nearly 16 million people.
Write names of barrages in Pakistan?
Rasul Barrage, Punjab
Tonsa Barrage , Punjab
Chashma Barrage, Punjab
Panjnad Barrage, Punjab
Guddu Barrage, Sindh
Shukkur Barrage, Sindh
Kotri Barrage, Sindh
Below are the dams built on different rivers in Pakistan:
Tarbela Dam
Tarbela dam is built on the river Indus and is the world’s largest earth filled dam. This dam was built in 1976 at a cost of 18.5 billion and almost 15000 Pakistani and 800 foreign workers worked on its construction.
It has the capacity of generating 3,478 MW of electricity which makes it Pakistan’s largest Hydro power station. It has a reservoir which is 97 km long and has a depth of 137 meters. This dam is located 103 km from the city of Rawalpindi.
Satellite view of the Tarbela Dam.
Mangla Dam
The Mangla dam is the world’s third largest earth filled dam and is built on the river Jhelum. The dam is located 115 km south east of Rawalpindi and is 3,353 meters long and 116 meters high form the river bed.
This dam was built, just like the Tarbela dam, as a result of the Indus basin treaty of Pakistan and India in 1960.
The dam has an elevation crest of 1,234 feet and is designed to store 5.88 MAF of water that is used for generating power. A Gakkhar fort is built at the centre of the dam form a panoramic view of the lake can be viewed.
On the right side of the dam there are two spillways one of which has the capacity of 900,000 cusecs while the second is an emergency spillway.
Power house at the Mangla Dam.
Khanpur Dam
Khanpur Dam
Khanpur is constructed on the beautiful Haro River located 48 km from Islamabad.
The Khanpur dam is a multipurpose dam which not only provides electricity to KPK but also provides drinking and irrigation water to Islamabad, Rawalpindi and many other cities of Punjab.
The construction of the dam started in 1963 and was completely built in 1983 costing nearly Rs 1352 million. The dam is almost 167 feet high and has the capacity to store 106,000 acres of water. It nearly supplies 110 cusecs water for electricity and 87 cusecs for irrigation and drinking water.
Warsak Dam
The Warsak dam is a huge, gigantic dam built on the Kabul River and is situated 30 km northwest of Peshawar.
It is a multipurpose 250 feet high and 460 feet long having a reservoir of 4 square miles and a storage capacity of 25,300 acre of water.
It has a generating capacity of 240,000 KW and gives water for irrigation to 110,000 acres of land.
It provides electricity to KPK and some areas of Punjab
Misriot Dam lake
Misriot Dam
Misriot dam is a small dam built on an artificial lake located 12 km south west of Rawalpindi. Misriot dam has a small storage capacity and mostly provides water for irrigation nd drinking to small villages and towns around the lake.
Tanaza Dam
Tanaza Dam just like the Misriot dam is a small dam with a small storing capacity.
It is built on a lake located 35 km south west of Rawalpindi on the Dhamial Road.
This dam too mostly stores water for irrigation purposes and to for drinking purposes. The atmosphere around the lake and the dam is quiet and peaceful, ideal for a day out on a picnic.
Simly Dam
Simly dam is a small dam which stores water for drinking purposes. It is built on the Simly Lake which is located 30 km from the city of Islamabad.
The lake if fed by the melting snow of Murree there for the water of the lake is more pure than the other lakes.
Ghazi Barotha Hydro Power Project
Ghazi Barotha Hydro power project is constructed on the Indus River and is located downstream of the Tarbela Dam.
This gigantic project was completed in 2004 and provides the country with a power of 1450 MW of powers 24/7.
This is an environment friendly dam and was built with the intentions to meet the shortage of electricity supply in the country. This project has a generation capacity of nearly 1450 MW of energy.
There are three main components of this project: a barrage, a power channel and a power complex. The barrage which is located 7 km downstream of the Tarbela dam regulates the water stream from the
Tarbela into the power channel. The power channel of this project is the world’s largest concrete lined power channel. The length of the channel is 52 km and it has a water depth of 9m. The flow from the barrage to the channel is 56,500 cusecs.
Despite of having such an ample supply of water and well built dams, it is sad to see that the country like Pakistan with such a highly agricultural land to be this poor.
