How Do Dams Benefit Ecosystems and Society?
A dam is a structure that is built on rivers, streams, or estuaries for conserving water. It directly helps to supply people with adequate water for consumption, industrial and irrigation purposes. Broadly, modern dams can be classified into 2 types– concrete dams and embankments. Concrete dams or masonry dams block streams that run through narrow gorges, whereas embankments control streams and rivers which flow through broad valleys.
An example of a masonry Dam in India is Nagarjuna Sagar Dam located in Andhra Pradesh. An example of an Embankment Dam in India is the Tehri Dam, located in Uttarakhand. A large section of India’s population suffers from a water crisis or mismanagement of water resources. To begin with, there is not enough clean water for drinking or irrigation purposes in many parts of the country. On the other hand, flash floods are also frequent in many regions. As a means to remedy this persistent problem, man-made structures like dams and reservoirs have been constructed across streams and rivers. The article discusses the uses, the main advantages and disadvantages of dams.
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Uses of Dams
Since we have developed a basic understanding of what a dam is, let us look into the uses of dams. It is considered as a significant water resource. They provide water for a variety of reasons, including home usage, irrigation, and industrial applications. Dams are also utilized to produce hydropower power and make river transportation easier. Dams are becoming increasingly important in everyday activities. Moreover, dams also promote local tourism thus contributing to national development. There are several uses of dams. Some of the most common ones are as follows
The water conserved in reservoirs provides freshwater to residential, industrial, and mining areas.
The conserved water satiates irrigation purposes.
Facilitates the process of generating energy from renewable sources, like hydropower.
Helps to regulate the flow of water of rivers and streams and protects communities residing down in the valley.
Facilitates water conservation for meeting future requirements.
With that being said, let’s proceed to find out the associated merits and demerits of dams.
Advantages of Dams
Dams offer an array of economic, social and environmental benefits and are useful for most problems pertaining to water conservation and its crisis management. On that note, let’s glance through the top advantages of dams –
Water Storage
Arguably, this is one of the primary uses of dams and reservoirs. The water stored in reservoirs helps to make up for water crises in dry seasons. It also ensures the regular water supply for residential, industrial and agricultural consumption.
Flood Control
Undoubtedly, mitigating floods is a major importance of dams. Dams help to control the flow of floodwater by diverting its course towards other uses, storing the excess water or releasing it with caution. In turn, it helps to save lives and resulting displacement.
Irrigation
One of the most significant merits of dams is the role they play in irrigation. Dams have helped farmers tackle the problem of watering crops significantly, which has resulted in a boost in crop production.
Electricity Production
Over the years, hydropower has emerged as an effective way of meeting the energy crisis in many regions of India. Also, being a clean source of energy, hydropower does not contribute to any kind of pollution. Tehri Dam, Srisailam Dam, and Sardar Sarovar Dam are some of the top hydropower plants in India.
Debris Control
Besides mitigating floods, dams often prove useful in retaining detrimental sedimentation. In fact, they may also come in handy in preventing the disposition of hazardous material and subsequent contamination.
Recreation
One of the benefits of dams is that they also provide recreational facilities to human beings. One can enjoy boating, skiing and fishing in the stagnant water. Maithon dam and Bhakra Nangal dam are popular among tourists as recreational hubs.
Disadvantages of Dams
Irrespective of their array of benefits, dams have a significant share of disadvantages. The following offers a brief idea about it.
Displacement of people during construction.
Reservoirs often emit a high percentage of greenhouse gases.
Often disrupts local ecosystems.
It disrupts the groundwater table.
Blocks progression of water to other countries, states or regions.
In conclusion of the article, we have discussed the advantages and disadvantages of dams, we have learned about the uses of a dam.
FAQs on Advantages of Dams in Biology
1. What is a dam and what is its basic principle of operation?
A dam is a large barrier constructed across a river or stream to obstruct and control the flow of water. Its basic principle involves creating a large water reservoir behind the barrier. This stored water has high potential energy due to its height. This energy can then be converted into other forms, such as kinetic energy to turn turbines for generating electricity, or it can be released in a controlled manner for irrigation and other purposes.
2. What are the primary purposes for which dams are constructed?
Dams, especially multipurpose dams, are constructed to serve several key objectives as per the CBSE curriculum. The primary purposes include:
- Hydroelectric Power Generation: Using the force of falling water to generate clean and renewable electricity.
- Irrigation: Storing water during rainy seasons and supplying it to agricultural fields during dry periods.
- Water Supply: Providing a consistent supply of drinking water for towns and cities.
- Flood Control: Regulating the flow of the river to prevent floods in downstream areas during heavy rainfall.
- Recreation: The reservoir created by a dam can be used for activities like boating, fishing, and tourism.
3. What are the main types of dams based on their structure?
Dams can be classified into several types based on their structural design and the materials used. The three main types are:
- Gravity Dams: These are massive structures, typically made of concrete or stone masonry. They resist the horizontal pressure of the water entirely by their own weight.
- Arch Dams: These dams are curved in plan and are built in narrow, rocky canyons. They transfer the water pressure to the abutments or sides of the river valley.
- Embankment Dams: These are large, artificial dams constructed from compacted earth or rock-fill. They are the most common type of dam and rely on their heavy weight to resist the force of the water.
4. What are some of the major advantages of building multipurpose dams?
Multipurpose dams offer a wide range of benefits that contribute to regional development. A key advantage is the integrated management of water resources. They provide a reliable source for irrigation, which boosts agricultural productivity and ensures food security. They are a significant source of hydroelectricity, a clean form of energy. Furthermore, they play a crucial role in flood prevention by storing excess water and are vital for supplying drinking water to urban areas.
5. How can the construction of a large dam negatively impact the environment and local people?
While dams have many benefits, they are also associated with significant social and environmental problems. The major negative impacts are:
- Social Problems: The construction of large reservoirs submerges vast areas of land, leading to the displacement of millions of local people, who lose their homes and livelihoods.
- Environmental Problems: They cause large-scale deforestation, loss of biodiversity, and disturb the aquatic ecosystem by obstructing the migration of fish.
- Sedimentation: The dam traps silt and sediment, which affects the fertility of downstream floodplains and deltas.
- Economic Problems: Building large dams requires enormous public investment without proportionate benefits, and the management of displaced people creates further economic strain.
6. Can you name five major dams in India and their significance?
India has several major dams that are crucial for its water and energy security. Five prominent examples are:
- Tehri Dam, Uttarakhand: The highest dam in India, built on the Bhagirathi River.
- Hirakud Dam, Odisha: One of the longest dams in the world, built on the Mahanadi River, primarily for flood control and irrigation.
- Sardar Sarovar Dam, Gujarat: A large gravity dam on the Narmada River, part of a major multipurpose project.
- Bhakra Nangal Dam, Himachal Pradesh: A concrete gravity dam on the Sutlej River, vital for irrigation in Punjab and Haryana.
- Nagarjuna Sagar Dam, Telangana/Andhra Pradesh: The world's largest masonry dam, built on the Krishna River.
7. What is a reservoir, and how does it differ from a natural lake?
A reservoir is a large, artificial or man-made lake created by building a dam across a river. While both are large bodies of standing water, they differ significantly. The primary difference is their origin: a reservoir is man-made for specific purposes like water storage, while a natural lake is formed through geological or ecological processes. Consequently, the water level in a reservoir can fluctuate drastically based on dam operations and seasonal demand, whereas a natural lake's level is more stable and influenced mainly by natural precipitation and evaporation.
