Dams are necessary for the survival of a country. Whether developing or developed no one can ignore its importance and existence. Dams are built across the river for various needs of human beings.
In India monsoon is the main source of water. Rivers mainly receive water during monsoon season only. So it is essential to store this water in reservoirs to regulate water discharge among different places.
When the natural flow of water is not sufficient to meet the public’s demand this reserve water of reservoir is released to meet the growing demands.
Growing population also puts pressure on the demand of more resources. Therefore there is always a need to build more and more dams.
The dams are built under several multi-purpose river valley projects. The motto of these projects is to store water for irrigation, generating electricity, prevent floods and enhancing afforestation in the reservoir area.
Till 2000, the number of dams reached to 4000 in India and it is gradually increasing.
Advantages of dams
- Dams store water in reservoirs especially during monsoon when the water discharge in rivers is high and in this way they prevent floods.
- The water of the reservoir is used to generate hydroelectricity which is a main source of power generation across the world and in this way it illuminates the world.
- The most important advantage of dams is irrigation. Because of dams India’s crop-production has increased remarkably in the last few years.
- The dams which are mainly constructed for the purpose of irrigation are called embankment dams. In such type of dams a wall is constructed with gates across the river valley to store water in the reservoir upstream.
- The reservoir area and the upstream area which is submerged to store water is called catchment area. The downstream which is used for irrigation is called the command area.
- Other than preventing floods, they also help the farmers in irrigation. The water supply from the reservoirs is used to irrigate crop land.
- The water provided by dams is also used for drinking and other industrial activities.
- Dams provide a natural wildlife habitat to some species and this way they are environmental friendly. Their existence creates an ecological system near the area and shelters a variety of species.
- The lakes are built to reserve the water provides an area for certain recreational activities like boating, fishing etc.
- The electricity generated through hydropower does not cause any environmental hazards like air pollution, acid rain etc.
- Dams help in utilizing the canals for navigation which reduces pressure on railways too.
- It is a renewable source of energy. Electricity can be generated whenever required using the energy stored in the form of water in dams.
Disadvantages of dams
The disadvantages of dams are mostly linked with it’s advantages. Everything has its own pros and cons.
- Though dams are the source of irrigation across the country yet they create problems for farmers living around reservoir areas.
- For building a reservoir a low land is needed which is good for crop production too. This means most of the times farmers are deprived of their lands which is a mean of their livelihood.
- The flooding of area for reservoir destroys the natural environment there.
- The cost of dam construction is very high. And they must be built enough strong to operate functionally for many years.
- Sometimes construction of big dams caused geological damage like earthquakes. An example of this damage is building Hoover dam, USA. It triggered a lot of earthquakes there.
- Building dams for development in one country affects the water supply in another country from which the river flows too.
- Construction of dams sometimes alters the natural water table level. For e.g. Aswan dam in Egypt has changed the water level of that area and caused huge damage to the monuments there.
- Most dams contain sediment storage and sooner or later when this storage is filled, we are left with no solution but to breach or abandon the land.
- Dams damage the ecosystem of some aquatic animals like some fishes migrate to upstream for breeding.
- Storage of water enhances the breeding of mosquitoes which sometimes lead to water borne diseases also.
Our former Prime Minister Jawaharlal Nehru had called the dams ‘temples of Modern India’.
Without dams a country cannot nurture its resources so they are an integral part of our system. India is a large country having lots of dam some of the few area;-
Tehri dam – recently built Tehri Dam is constructed on Bhagirathi River in Uttarakhand.
It is the highest dam in India having 261 meters of height and eighth tallest in world. It’s first phase was completed in 2006 and the two phases are still under completion. It has the capacity of installing 1,000 MW of electricity.
Bhakra Nangal Dam– this gravity is built across river Satluj in Himachal Pradesh having height of 225 meters.
It has them second largest reservoir in India, under the name ‘Gobind Sagar Lake’. It can generate 1325 MW of electricity.
Sardar Sarovar dam– better known as ‘Narmada Dam’ is the largest dam on holy river Narmada in Gujarat.
This gravity dam is built to support hydroelectricity of strength 1450 MW of India namely Gujarat, Madhya Pradesh, Maharashtra and Rajasthan. It is the second largest concrete gravity dam on river Narmada.
Hirakund dam– across the river Mahanadi it is built in state Orissa. It is 26 km in length hence is one of the largest dams in India. It is 26 km in length hence Is one of the longest dams in India.
It has two towers namely “Gandhi Minar” and “Nehru Minar”. It has a big reservoir whose length is 55 km which supports irrigation, power generation and flood control in that area.
Nagrjuna Sagar Dam– it is the world’s largest masonry Dam built in 1967 with a height of 124 meters built across river Krishna in Andhra Pradesh.
This dam has a reservoir in the form of a lake which is the largest man-made lake in the world. It is a symbol of pride for Indians. This 1.6 km long dam has 26 dam gates. Its power generation capacity is 815.6 MW.