Question

What was the major challenge associated with Bhakra-Nangal project?

• A. Soil erosion
• B. Loss of biodiversity like flora and fauna
• C. Desertification
• D. Deforestation

Hint:

• Large dams create reservoirs that submerge large areas of land.
• This leads to:
  • Loss of terrestrial habitats (forests, grasslands), resulting in loss of flora and fauna (biodiversity).
  • Displacement of human populations.
  • Alteration of river ecosystems and impacts on aquatic life.
• While deforestation is a part of it, "loss of biodiversity" is a broader ecological impact.

Answer 1

The Correct Option is B

Large dam projects like the Bhakra-Nangal project, while providing significant benefits such as irrigation, hydroelectric power, and flood control, also have associated environmental and social challenges. Some common challenges include:

• Displacement of People: Large reservoirs submerge vast areas, leading to the displacement of local communities. This was a significant issue with Bhakra.
• Loss of Biodiversity (option b): The creation of a large reservoir (Gobind Sagar Lake in the case of Bhakra) leads to the submergence of terrestrial habitats, including forests, grasslands, and agricultural lands. This results in the loss of flora (plants) and fauna (animals) that inhabited those areas, and can also impact aquatic biodiversity by altering riverine ecosystems.
• Deforestation (option d): Submergence of forest areas is a direct consequence of reservoir creation, leading to deforestation. This is closely linked to loss of biodiversity.
• Impact on River Ecology: Dams alter the natural flow regime of rivers, affect sediment transport, water temperature, and can be barriers to migratory fish.
• Siltation: Reservoirs can trap sediment, reducing their storage capacity over time and depriving downstream areas of fertile silt.
• Waterlogging and Salinization: Intensive irrigation from canals can sometimes lead to waterlogging and soil salinization in command areas if drainage is inadequate.
• Soil Erosion (option a): While dams can trap sediment, construction activities and changes in land use in the catchment can sometimes exacerbate soil erosion. However, the reservoir itself submerges land rather than directly causing erosion over that area. Erosion in the catchment is a concern for reservoir siltation.
• Desertification (option c): This is typically associated with land degradation in arid/semi-arid areas leading to desert-like conditions. While mismanagement of water resources can contribute to land degradation, it's not usually cited as the primary direct challenge of a specific dam project like Bhakra in the same way as submergence-related impacts.

Given the options, "Loss of biodiversity like flora and fauna" (b) is a major and direct ecological consequence of large dam projects due to habitat submergence and alteration. Deforestation (d) is a component of this loss. Bhakra-Nangal led to the submergence of significant land area, impacting local ecosystems. \[ \boxed{\text{Loss of biodiversity like flora and fauna}} \]