UPSC Mains 2022 GS Paper 3 Q18: model answer
Explain the causes and effects of coastal erosion in India. What are the available coastal management techniques for combating the hazard?
What the question wants
Explain the causes and effects of coastal erosion in India and the coastal management techniques available.
How to structure it
Causes, effects, techniques.
- Scale
- Natural causes
- Human causes
- Effects
- Hard techniques
- Soft techniques
- Planning tools
How to think it through
NCCR (2022): ~33.6% of coastline under erosion (1990–2018); West Bengal (~60%), Kerala (~46%), TN (~43%), Puducherry (~57%). Natural: waves, storms, cyclones, sea level rise, currents, longshore drift. Human: ports and breakwaters interrupting sediment (Puducherry harbour), dams reducing sediment, sand mining, mangrove removal, construction on dunes. Effects: loss of land and homes, fishing villages, saltwater intrusion, tourism, infrastructure, habitats (turtles). Hard: seawalls, groynes, breakwaters, revetments. Soft: beach nourishment, dune restoration, mangroves, artificial reefs (Puducherry 2017 reef restored beach), geotextile tubes. Planning: CRZ, shoreline management plans, setback lines, ICZM, sediment bypassing.
Model answer
Puducherry lost much of its famous beach after a harbour was built in the 1980s blocked the natural northward drift of sand. In 2017, an artificial reef and sand nourishment helped bring part of the beach back. The town's story contains both the cause and the cure of coastal erosion.
Scale
- About one-third of India's coastline eroded between 1990 and 2018 (National Centre for Coastal Research).
- Worst in West Bengal, Puducherry, Kerala and Tamil Nadu.
Natural causes
- Waves, storms and cyclones that remove sand.
- Longshore currents that move sediment along the coast.
- Sea level rise pushing the shoreline inland.
Human causes
- Ports, breakwaters and groynes that block sand on one side and starve the other.
- Dams that trap river sediment before it reaches the delta.
- Sand mining from beaches and rivers.
- Removal of mangroves and dunes.
- Construction too close to the shore.
Effects
- Loss of land, homes and fishing villages.
- Damage to roads, ports and tourism beaches.
- Saltwater intrusion into farmland and wells.
- Loss of habitat for turtles and shorebirds.
- Displacement of coastal communities, as in Uppada (Andhra) and parts of Kerala.
Hard techniques
- Seawalls and revetments: protect land but often worsen erosion nearby.
- Groynes: trap sand, starving downdrift beaches.
- Offshore breakwaters: reduce wave energy.
Soft techniques
- Beach nourishment by adding sand.
- Dune restoration and planting.
- Mangroves and salt-marsh belts.
- Artificial reefs and geotextile tubes.
Planning tools
- CRZ Notification, 2019 and hazard lines.
- Shoreline management plans for whole sediment cells.
- Sand bypassing at ports.
- Satellite monitoring of shoreline change by NCCR and ISRO.
- Integrated Coastal Zone Management.
The sea does not respect state boundaries; coastal management must follow the movement of sand, not the lines of districts.
Draw: A coastline with a harbour: sand building up on one side, eroding on the other.
Keywords, cases and data to drop in
NCCR, one-third coastline eroding, longshore drift, Puducherry harbour, artificial reef 2017, dams and sediment, sand mining, seawalls, groynes, breakwaters, beach nourishment, dunes, mangroves, geotubes, CRZ 2019, shoreline management plan, ICZM.
Where most answers lose marks
- Recommending only seawalls. Soft measures and planning are expected.
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Question text as printed in the official UPSC Civil Services (Main) question paper. The model answer is original Battle IAS work; use it to learn structure, not to memorise.
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