Coastal Erosion

According to a recent study, fishermen and other coastal Tamil Nadu residents' livelihoods are in danger due to coastal erosion. More than 4,450 acres of land have been lost as a result of erosion along about 43% of the coast.

On the east coast, the area subject to erosion is growing by 3 meters year, whereas on the west coast, it is growing by 2.5 meters annually. By altering the shoreline, development initiatives intended to stop marine erosion and promote economic growth are making matters worse.

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INDIA COASTLINE PRONE TO COASTAL EROSION

• India's coastline stretches across 13 States and Union Territories (UTs) and is 7516.6 km (6100 km of mainland + 1177 km of islands).
• The longest state coastline is found in Gujarat (1214.7 km), followed by Andhra Pradesh (973.7 km) and Tamil Nadu (906.9 km).
• Among UTs, the Andaman & Nicobar Islands have the longest coastline (1962 km).
• The Konkan coast (Maharashtra and Goa Coast) is a coast of submergence, whereas the Coromandel coast (Tamil Nadu) is a coast of emergence.

COASTAL EROSION

• Coastal erosion is the process by which the sea erodes land; it is frequently brought on by powerful waves that break the coast.
• It is the process through which erosion of rocks, soils, and/or sands along the coast occurs as a result of intense wave action, coastal flooding, and local sea level rise.

CAUSES OF COASTAL EROSION

• Waves: Through abrasion, erosion, and hydraulic action, strong waves can damage coasts. For instance, the waves in the English Channel are constantly eroding the Dover cliffs in England.

  • The quantity of erosion can be influenced by high and low tides, especially in places with large tidal ranges. For instance, the severe tides in Canada's Bay of Fundy can seriously destroy coasts.
  • Long-term and progressive erosion may result from wind and sea currents. For example, wind and sea currents migrate from south to north along the Tamil Nadu coast for eight months of the year, carrying sand with them. This direction flips throughout the four months of the northeast monsoon.

• Hard Structures: Groynes, breakwaters, and ports obstruct the flow of sand naturally, resulting in sand accumulation on the upstream side and erosion on the downstream side.

  • Low-lying wooden or concrete structures called groynes are made to collect silt and release wave energy.

• Development initiatives: By changing the shoreline, infrastructure initiatives intended to promote economic expansion are making erosion worse.

  • For example, the reclamation of land in Mumbai and other neighboring coastal locations leads to erosion.

• Port Expansion: When harbors and ports are enlarged, the natural flow of sand and sediment along the shore is impeded by features like jetties and breakwaters.

  • Increased erosion on one side of the building and silt buildup on the other may result from this. For instance, the Adani Kattupalli Port in Tamil Nadu and the Ennore Port.

COASTAL EROSION PROCESS

There are four main processes of coastal erosion. These are corrasion, abrasion, hydraulic action and attrition.

EFFECT OF COASTAL EROSION

• Loss of Land: Erosion can lead to the loss of valuable coastal land, affecting property and infrastructure.

  • E.g. the loss of land along the Marina Beach area in Chennai severely affected property and public spaces.

• Impact on Coastal Ecosystems: Erosion can destroy habitats such as mangroves, salt marshes and sand dunes, which are crucial for various species.

  • E.g., In the Sundarbans region of West Bengal, erosion has led to the loss of mangrove forests.

• Flooding Risk: Erosion can reduce the natural barriers that protect coastal areas from flooding.

  • E.g., In coastal regions of Kerala, erosion has increased the risk of flooding, affecting low-lying areas and exacerbating the impacts of heavy rains and storms.

• Displacement of Communities: Erosion can force communities to relocate, leading to social and economic disruption.

  • E.g., coastal erosion in the Andaman and Nicobar Islands has led to the displacement of local communities, particularly on smaller islands where land loss is more pronounced.

• Salt Water Intrusion: Coastal erosion can lead to the salinisation of agricultural land, reducing crop yields.

  • Eg: In Andhra Pradesh, saltwater intrusion negatively affected crop yields and reduced the productivity of farmland.

• Impact on Marine and Coastal Biodiversity: It can alter ecosystems and food chains.

  • E.g., it hampered the health of marine ecosystems in the Lakshadweep Islands.

MAJOR TAKEAWAYS FROM THE STUDY REGARDING TAMIL NADU COAST

HOW TO PREVENT COASTAL EROSION

• Vegetation: Strategic planting of seagrass and other coastal plants helps prevent erosion. The roots of these plants help anchor the sand and ensure that it is not washed off in erosion.

• Beach Nourishment: Nature-based or "green infrastructure" protection measures enhance the natural ability of shorelines to absorb and dissipate storm energy without interfering with natural coastal processes.

  • E.g., planting mangroves to serve as a buffer against erosion.

• Coastal Restoration: It is aimed at restoring habitats such as wetlands to benefit marine and coastal species by providing important nursery grounds. It has environmental benefits like carbon sequestration and restoration of open spaces.

• Regulatory Measures: Zoning laws, building codes, and maintaining minimum distance from the shoreline for new buildings or infrastructure facilities to regulate coastal development.

GOVT INITIATIVES TO PREVENT COASTAL EROSION

• Shoreline Mapping System: The National Centre for Coastal Research (NCCR) has observed that 33.6% of the Indian coastline was vulnerable to erosion, 26.9% was under accretion (growing) and 39.6% was in a stable state.
• Hazard Line: The Ministry of Environment, Forest & Climate Change (MoEFCC) has defined the hazard line to indicate shoreline changes and sea level rise. It is used for disaster management, adaptive planning, and mitigation measures in Coastal States/UTs.
• Coastal Regulation Zone (CRZ) Notification 2019: It permits erosion control measures and establishes No Development Zones (NDZ) to protect the coastline from encroachment and erosion.
• Coastal Zone Management Plans (CZMP): Following a National Green Tribunal (NGT) order, States/UTs have been asked to finalize CZMPs, including mapping of erosion-prone areas and preparing Shoreline Management Plans.

CONCLUSION

Coastal erosion threatens India's coastlines, harming the environment and local communities. Natural and human factors worsen shoreline changes, leading to habitat loss and affecting fishermen. Improved shoreline mapping and government measures, like hazard lines and CRZ Notification 2019, aim to manage and protect coastlines. Ongoing efforts, such as CMIS, seek to enhance these strategies.