Dams have impacted human civilization by bringing prosperity through their various uses. They have simultaneously, but less frequently, caused devastation to the human population, crops, and biodiversity in cases of failure. A dam is an obstruction in the way  water flows which is planned by human beings in order to achieve one or more various purposes.  They may include creating water storage, preserving and raising the level of a huge body of water, increasing the speed of water flow, preventive flood control, irrigation, prevention of soil erosion, generation of hydroelectricity, and many other uses. Hydroelectric power obtained from dams meets about one-fifth of the world’s electricity requirements.

1. Three Gorges Dam in China

The Three Gorges Dam is located in the Yiling district in the Hubei province of China. It is a hydroelectric dam spanning the Yangtze River being the longest river in China. Comprising 32 turbines with an installed capacity of 22,500 MW, it is the world’s largest power station. In the year 2012, it generated the electricity at par with the then largest power station of the Itaipu Dam. Building the Three Gorges Dam had been controversial since its very inception in 1993. Its building was considered to be dangerous, and it was cautioned that the heavy weight of dam might change Central China’s geology and was likely to displace a large human population and archaeological sites of historic importance. Building of this dam  was originally intended to increase the shipping capacity of the Yangtze River decreasing its flood potential and generating much-needed electricity. Whereas the Chinese government claims it to be a great, economic, social and environmental success, the facts are that it has displaced 1.3 million people, caused notable ecological changes, and has increased the risk of landslides.

2. Aswan Dam

The Aswan Dam, also known as High Dam, is located across the Nile River in Aswan, Egypt. The first dam was designed by Sir William Willcocks, and its construction started in 1898 ending in 1902. It has greatly impacted the agriculture and economy of Egypt. Since ancient times, the agriculture and economy of Egypt depended upon the Nile River which played a dual role. In times of fairly high waters, the river brought fertile soil and nutrients rendering a large area of land highly fertile and productive. In the days of very high days, the river displaced a large population and devastated many areas in its path. In the low days, the land was deprived of irrigation with consequent low-yielding crops and famine. Building the Aswan Dam has optimized the situation by preventing floods and by ensuring a constant water supply by virtue of a raised level of water in the dam. Both Russia and America helped the Egyptian government in building the Aswan dam.

3. Hoover Dam

Hoover Dam, named after President Herbert Hoover, was originally called Boulder Dam after the name of the labor colony built in the vicinity of the dam for the workers. It is located in the Black Canyon of the Colorado River near Boulder City at the borders of the U.S. states of Nevada and Arizona. Recognizing the potential of the dam to control flooding and regulate irrigation and generate electricity, Congress approved its construction in 1928. The winning bid was submitted by a consortium of six companies. Building of the arch-gravity dam started in early 1931, and construction of the dam was completed on March 1, 1936, 2 years earlier than the scheduled date of completion. Hoover Dam is a tourist attraction and is visited by more than one million people every year.

4.  The Itaipu Dam

The Itaipu Dam is named after the island Itaipu that existed at the site of the dam. In the Guaranj language, ‘Itaipu’ means ‘the sounding stone.’ The dam is owned commonly by Brazil and Paraguay. It is located about 15 kilometers to the north of the Friendship Bridge on the Panama River at the border of Brazil and Paraguay. In terms of its operating output, it is the largest hydroelectric dam, while in terms of installed capacity, it is next only to the largest dam in the world, the Three Gorges Dam with a 22,500 MW installed capacity. The installed capacity of the Itaipu Dam is 14,000 MW. The dam is provided with 20 generators of which 10 generate at 50HZ for Paraguay while the other 10 generate 60 HZ for Brazil.

5. The Gordon Dam

The Gordon Dam is an arch dam built on the Gordon River in Tasmania, Australia. It is 192 meters long and 140 meters high. It is the fifth tallest dam in Australia, and water in it falls from 183 meters into its 3 turbines of 144 MW to generate 432 MW power. This meets about 13 percent of the electricity requirements of Tasmania. The Gordon Dam was designed by the chief engineer Dr. Sergio Guidici. The Gordon Dam has created Lake Gordon on the upper side of the Gordon River in Southwest Tasmania, Australia. The surface area of Lake Gordon is 105 square miles, and its storage capacity is 3.0 cubic miles.

6. Lake Vyrnwy Dam

Lake Vyrnwy Dam is located in Montgomeryshire, Powys, Wales. This unique, stone dam, designed by Dr.George Deacon, was built in the 1880s. Its construction started in 1881 and was completed in 1888. It was originally intended for supplying fresh water to Liverpool and Merseyside. The dam is built of big blocks of Welsh slate. The dam is 44 meters high, 357 meters long, and 39 meters wide at the base. It has 25 arches and 2 small towers. The site of the dam is designated as a National Nature Reserve a site of special scientific interest and a special area of conservation

7. Mangla Dam ”œ Pakistan

Tarbela Dam is the largest, earth-filled dam in the world and the second most voluminous by structure. It was built in 1974 on the Indus River at about 50 kilometers from Islamabad in the Hazara District of the Khyber Pakhtunkhwa Province, Pakistan. It is 148 meters high and forms Tarbela Reservoir having a surface area of about 97 square miles. It was designed to store the Indus River’s  water for irrigation, flood control, and generation of hydroelectric power. It has 14 generators. The source of the Indus River is the glacial melting water from the Himalayas which brings a lot of rock sediment with it. Taking into consideration the current yearly rate of sedimentation, it is estimated the dam will have a useful lifespan of about 80 years until 2060.

8. Mratinje Dam

The Mratinje Dam is a concrete arch dam built on the Piva River in Montenegro, a southeastern European country. The dam was designed by Energoprojekt, and the construction was completed in 1975. It created Lake Piva covering a 12.5 square kilometers area. The dam is 220 meters high, 268 meters long, and 36 meters thick at its base. It is one of the highest dams in Europe. The foundations of the dam are 38 meters deep and contain 820,000 cubic meters of concrete and 5,000 tons of steel. It has 3 turbines and each can generate 120 MW electricity.

9. Glen Canyon Dam

Glen Canyon Dam is built on the Colorado River near the town of Page in northern Arizona, United States. The purpose of the dam was to regulate the flow of the upper Colorado River basin to the lower side. The generation of hydroelectricity was also the main objective. The dam created Lake Powell which is the second largest lake in the country. Construction of the dam started in 1956 and continued until 1966. The dam was on the verge of collapse under pressure from heavy flooding, but the disaster was averted. Construction of the dam has impacted the ecology of the region.

10. Contra Dam

Contra Dam, also known as the Verzasca Dam, was built on the Verzasca River of Ticino, Switzerland. Its construction started in 1961 and was completed in 1965. The dam is 220 meters high, 380 meters long, and covers 44,500 square meters area. It is the fourth tallest dam in Switzerland. The dam is looked after by Verzasca SA. It is a popular site for bungee jumping which is a quite risky and thrilling sport involving jumping from a high place while tied with an elastic cord causing a free fall and a rebound. Contra Dam became especially popular for this sport after a stuntman jumped from it in the opening scene of the 1995 movie The Golden Eye.

Conclusion:

Whereas mankind has always learned from nature, it has at times tried to harness some natural forces. By doing so it has definitely benefited from their immense potentials but not always. The construction of dams is an example of  harnessing such elements. While trying to change the course of huge bodies of water like great rivers, a great deal of planning for optimized results is required. Human efforts to overcome natural sources of energy through thoughtless exploitation of natural resources are a sure recipe for disaster.