Construction of Dams on River : Importance and Effects

Rivers are freshwater bodies that originate from a small source and finally joins sea or Ocean. Rivers were very important for human race to survive as they are the nearest source of fresh water in early days. Even the four oldest and greatest human civilization flourished on the banks of River. The Mesopotamian Civilization Flourished on the banks of River Tigris, Egyptian Civilization on the banks of River Nile, Chinese Civilization on the banks of Yellow River and Harappan Civilization on the Banks of Indus River.  Apart form that the most fertile land existing on earth can be found around the river banks. The Sunder ban delta of India-Bangladesh and Nile delta of Egypt are the best example of this. With the invention of electricity and its growing need Humans were forced to find alternate ways to generate electricity and one of the best method to generate electricity was via water. Hydroelectricity is the cheapest and cleanest form of electricity that we can get and it is always believed that the hydroelectricity doesn’t impact environment. If we look at the way hydroelectricity is generated we all will conclude that indeed it is the cleanest form of energy but in a long race this form of energy is too effecting our environment. When I was in school I used to think the same what I have mentioned above. But few years back I watched a documentary by National Geographic Channel. The documentary was about Colorado river that flows in the western part of United States of America and impact of two dams built on it i.e. The Hoover Dam and the Grand Coulee Dam. After watching the documentary I started reading the impact of Dams on River of India. To my surprise the dams built on different Rivers of India have do impacted the natural flow of river as well as disturbed the natural ecology of the river. Although the rivers in India are more prone to the pollution caused by millions of people living on its banks and industries situated on its bank. In reality this factor has too effected the rivers heavily and in this article we would be discussing the same i.e. impact of Dams on River.

Three Gorges Dam built on Yangtze River in China. It is the biggest dam in the world.
Three Gorges Dam built on Yangtze River in China. It is the biggest dam in the world.

Dams are one of the finest example of building ability of Human Race. Humans have developed some of the finest dams on some of the biggest and toughest rivers of the world. The Three Gorges Dam on Yangtze river and Bhakra Nangal Dam on Satluj river are the best example of Dam construction in the world. First Prime Minister of India Mr. Jawahar Lal Nehru said that Dams are the modern temple of Independent India and in his tenure he commissioned some of the initial dams built in India. Building one dam on river was fine but over a period of few years many more dams were commissioned on the same river their by restricting the flow of river in summer season. Some of the mightiest rivers of the world looks like a canal in the summer season due to this. While doing my study on effects of Dam on River read the case study of Ganges River as it is the longest river in India and nearly 40% of Indian population is dependent on this river. There are nearly 10 dams (bigger and smaller) constructed throughout the flow of river Ganges. Farakkha Barrage constructed just before river entering into Bangladesh hols the water further and the stored water is used for irrigation purpose in the summer months. In the upper course of the river there are nearly 7 dams that are already operational and 14 more are either under construction or study and research is going on for construction of Dams.

Tehri Dam constructed on Ganges River
Tehri Dam constructed on Ganges River

The two impact caused by the construction of Dams are 1: It stops the natural flow of water their by stopping the natural flow of sediments carried by the river water. 2: The stagnated water caused change in temperature which effects the breeding capability of marine animals. The fine soil particle carried by river is called the alluvial soil and this soil is very fertile in nature. It is due to the presence of this the initial human civilizations settled on the banks of river. When the river water is moving it carries the particle along with it but once the water gets stagnated the sediments gets settled on the river bed and doesn’t reach to other places. So this causes the river bed around the dam to increase year by year and depletion of soil quality at other places. Another impact caused by building of Dams is that it effects the breeding cycle of Marine Animals. Once the water of river is stagnated it looses its heat and gets cold. Many marine animals living in the river require a specific temperature to breed and since now the temperature of water is less they are not able to lay their eggs. many species of marine animals are on the verge of extinction due to this. While I was watching the documentary they covered the breeding cycle of Hump buck chap and effects of temperature on its breeding cycle. The same impact can be witnessed on the Ganges River Dolphin which is few breed of dolphin living in fresh water. There number have been significantly reduced due to this. There are many more impacts of construction of Dams like whole human population has to shift from the place as it will submerged under water and will affect the animals living in that area.

My point is construction of Dam is not harmful but constructing multiple dam on a single river will eventually kill the river. Rives which were once known as the cradle of civilization are now struggling for their own existence and it is due to numerous steps taken by Human being. When Tehri dam was commissioned on Ganges River various environmentalists protested against it but government suppressed their voice. Now its effect can be seen on the river Ganges which is life line of India.