[Model Answer QP2022 GS3] Explain the cause and effects of coastal erosion in India. What are the available coastal management techniques for combating the hazard?

Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural. In other words, Coastal erosion is the process by which local sea level rise, strong wave action, and coastal flooding results in eroding  or carrying away rocks, soils, and/or sands along the coast.
According to the Ministry of Earth Sciences, 34% of our coastline is subjected to varying degrees of erosion. 

The causes of coastal erosion in India

  1. Action of breaking waves especially in the west coast as it is a submergent coast and hence highly vulnerable to erosion.
  2. Rising sea level due to climate change and increase in the frequency of storm surges.
  3. Dredging, sand mining and coral mining have contributed to coastal erosion.
  4. Reduction of sediment supply due to damming of the rivers. 
  5. Removal of mangroves and other coastal vegetation exposed the coast to strong coastal waves.

The effects of coastal erosion in India

  1. Loss of Habitat. Ex: destruction of mangroves or deltaic ecosystem in Godavari or Mahanadi delta. 
  2. Degradation of coral reef due to deposition of silt.
  3. Increase turbidity of water. 
  4. Reduce the tolerance to face natural hazards such as Tsunamis and Storm surges. 
  5. Reduce Sand volumes to compensate for the natural littoral processes.
  6. Loss of livelihood for coastal communities as fishing as an economic activity losses its viability. 
  7. Collapse of tourism.
  8. Incursion of salt water into the land thereby affecting the coastal aquifers. 

Available coastal management techniques

  1. Beach Nourishment: Beach nourishment involves replenishing the sand on a beach to widen it. Sand dunes act as a good barrier against coastal flooding and erosion and they can be exploited as a natural defence against the sea. 
  2. Habitat restoration- mangroves and coastal Vegetation: They act as a buffer to strong wave actions, Tsunamis and Storm surges. Vegetation can slow the impact of erosion
  3. Using Geosynthetic tubes that are being used along the coast in Odisha.
  4. Sea Walls: Giant walls that span entire coastlines and attempt to reduce erosion and prevent flooding in the process. 
  5. Groynes: They’re low lying wooden walls that extend out to sea. The idea of groynes is to capture sand that moves down the beach via longshore drift and help build up a larger section of beach in front of an area that’s experiencing coastal erosion.
  6. Gabions: Gabions are quite simply bundles of rocks in a metal mesh. They’re placed at the base of a cliff in an attempt to reduce the impact of waves on the cliff and prevent the cliff from being undercut.
Similar to any other maritime country, India’s long peninsular region constantly battles erosion. The developmental activities are often carried out without a clear understanding of the coastal dynamics. Hence developmental activities must be in line with an atlas of Coastal Vulnerability Index (CVI) published by INCOIS. 

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