Coastal Erosion

Union Ministry of Earth Sciences has informed the Lok Sabha that of the 6,907 km long Indian coastline of the mainland, about 34% is under varying degrees of erosion.

What is ‘Coastal Erosion’?

• Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms.
• All coastlines are affected by storms and other natural events that cause erosion; the combination of storm surge at high tide with additional effects from strong waves—creates the most damaging conditions.
• The extent and severity of the problem is worsening with global sea level rise.

Processes of Coastal Erosion –

• Hydraulic Action – Hydraulic Action is the sheer force of water crashing against the coastline causing material to be dislodged and carried away by the sea.
• Abrasion – Abrasion is when rocks and other materials carried by the sea are picked up by strong waves and thrown against the coastline causing more material to be broken off and carried away by the sea.
• Attrition – Attrition is when material such as rocks and stones carried by waves hit and knock against each other wearing them down. As these materials are worn down sand and rounded beach pebbles are formed.
• Compression – Compression occurs in rocky areas when air enters into crack in rock. This air is trapped in cracks by the rising tide, as waves crash against the rock the air inside the crack is rapidly compressed and decompressed causing cracks to spread and pieces of rock to break off. Compression is one of the main processes that result in the creation of caves.

Coastal Erosion in India –

• India has 9 coastal states – Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Odisha, West Bengal. The length of the coastline of mainland is approximately 6,907 km.
• 26% of the coastline is of an accreting nature, and the remaining 40% is in a stable state.
• Some stretches of India’s shoreline are subject to varying degrees of erosion due to natural causes or anthropogenic activities.
• As many as 98 coastal pockets of the country have been facing sea erosion.
• Planning and execution of anti-sea erosion measures are undertaken by the maritime states and UTs as per their own priority and from their own resources. The role of the Central government is technical, advisory and catalytic in nature.

NCCR Report –

• The National Centre for Coastal Research (NCCR), Chennai, under Ministry of Earth Sciences is monitoring shoreline erosion since 1990 using remote sensing data and GIS mapping techniques.
• The NCCR, in July 2018, had released a report on ‘National Assessment of Shoreline Changes along Indian Coast’.
• Major Findings –
  • • In terms of percentage, West Bengal, located on the eastern coast of the country, with a 534 km-long coastline, suffered erosion along about 60.5% of the coast over the period from 1990 to 2018.
    • This is followed by Kerala, Tamil Nadu and Gujarat.
    • In the Union Territory of Puducherry, about 56.2% of its coast (23.42 km) recorded erosion.