Question

What is dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.

Answer 1

Hint: Dams are important because they provide water for industrial, domestic and irrigation purposes. Dams often provide river navigation and hydroelectric power production. Building dams have many advantages as well as disadvantages.

Complete answer:
A dam is built across a river or stream to control water through the placement of a blockage of earth, rock and/or concrete. Dams are usually built to store water in a reservoir. This stored water is later used for a variety of applications such as municipal water supplies and irrigation. Water stored in reservoirs can also be directed to flow through large hydraulic turbines, producing electric power for use in homes and industries. Since the reservoir water that is used to generate electricity is continuously replenished hydroelectric power is considered a renewable source of energy.

A dam using canal and locks, such as a series of locks on the Panama Canal, enables navigation through the human-made water route that must overcome elevation differences. By building large dams, large hydro potentials can be exploited for meeting power needs on a national or regional basis. Besides generating power, hydroelectric projects have the benefits of drinking water requirements and meeting irrigation etc.

The disadvantages of large dams are:
• Flooding of large areas of land which results in destroying fauna and flora.
• Construction of dams across the rivers leads to deforestation which in turn results in the loss of biodiversity. Also the flora and fauna get affected by altering the physical characteristics of the river below the dam.
• Impeding fish migration, and thereby killing large numbers of fish that pass through hydroelectric turbines.
• Causing serious ecological problems like removal of forest, soil erosion etc.

Hence, the correct answer is option (B).

Note: Building large dams causes many other issues as well: displacing local people without rehabilitation, loss of livelihood of the tribal community etc. Also, a huge amount of monetary investments is required for the construction of dams. In recent years, engineers and scientists have begun a method of water resource management called adaptive management. This helps to manage reservoirs and their releases to be less harmful to terrestrial and aquatic wildlife and plants, as well as humans residing below the dam.