05-August-2024-Editorial

COASTAL EROSION IN TAMIL NADU

Coastal erosion is a significant issue affecting Tamil Nadu’s coastline, impacting local communities, fishers, and infrastructure.

Recent studies reveal severe erosion, threatening livelihoods and exacerbated by development projects.

Key Findings of the Study

• Extent of Erosion: Tamil Nadu’s coastline is heavily affected, with nearly 43% experiencing erosion. Over 4,450 acres of land have been lost, and the erosion rate is increasing by about 3 meters per year on the east coast and 2.5 meters per year on the west coast.
• Impact of Development Projects: Infrastructure projects meant to combat erosion and boost economic growth are contributing to the problem. Structures like ports, breakwaters, and groynes disrupt natural sand movement, causing erosion on one side and sand accumulation on the other.

What is Coastal Erosion?

Definition: Coastal erosion refers to the process where the sea wears away the land due to strong wave action, leading to the loss of rocks, soils, and sands along the coastline.

Processes:

• Corrasion: Strong waves hurl beach material against cliffs, creating wave-cut notches.
• Abrasion: Sand and larger fragments carried by waves wear down the base of cliffs, similar to sandpaper.
• Hydraulic Action: Waves compress air in cliff cracks, causing explosive release and breaking off chunks of rock.
• Attrition: Waves cause rocks and pebbles to collide and break into smaller pieces.

Causes of Coastal Erosion

• Waves: Powerful waves cause erosion through abrasion, corrasion, and hydraulic action. For example, the cliffs of Dover in England are eroded by English Channel waves.
• Tides: Significant tidal ranges can affect erosion rates. The Bay of Fundy in Canada experiences extreme tides that contribute to coastal erosion.
• Wind and Sea Currents: Seasonal wind and currents influence sand movement. In Tamil Nadu, currents move sand from south to north for most of the year, reversing during the northeast monsoon.
• Hard Structures: Ports, breakwaters, and groynes block natural sand movement, causing erosion on the down-current side and sediment accumulation on the up-current side. For example, Ennore Port and Adani Kattupalli Port in Tamil Nadu affect sand distribution.
• Development Projects: Projects like land reclamation and port expansion alter coastlines, worsening erosion.

Impacts of Coastal Erosion

• Loss of Land: Erosion leads to the loss of valuable land, affecting property and infrastructure. For instance, Marina Beach in Chennai has lost significant land area.
• Impact on Coastal Ecosystems: Erosion destroys critical habitats like mangroves and salt marshes. In the Sundarbans, erosion has led to the loss of mangrove forests.
• Flooding Risk: Erosion reduces natural flood barriers, increasing flood risk. Coastal regions in Kerala face heightened flooding due to erosion.
• Displacement of Communities: Erosion forces communities to relocate, causing social and economic disruptions. The Andaman and Nicobar Islands have seen such displacements.
• Saltwater Intrusion: Erosion can lead to salinization of agricultural lands, affecting crop yields. Andhra Pradesh has experienced reduced crop productivity due to saltwater intrusion.
• Impact on Marine Biodiversity: Erosion can disrupt marine ecosystems and food chains. The Lakshadweep Islands’ marine health has been negatively affected.

Mitigation Strategies

• Vegetation: Planting seagrass and coastal plants helps stabilize sand and reduce erosion.
• Beach Nourishment: Enhancing shorelines with natural buffers like mangroves helps absorb storm energy and protect coasts.
• Coastal Restoration: Restoring wetlands and other habitats supports marine species and provides carbon sequestration benefits.
• Regulatory Measures: Implementing zoning laws and building codes to regulate coastal development helps prevent erosion.
• Government Initiatives: Various measures, including shoreline mapping, hazard lines, and Coastal Regulation Zone (CRZ) Notification 2019, aim to manage coastal erosion and protect coastlines.

Conclusion

Coastal erosion poses a significant threat to Tamil Nadu, affecting land, ecosystems, and communities.

While development projects often worsen the issue, strategies such as vegetation planting, beach nourishment, and regulatory measures can help mitigate erosion and protect coastal areas. Ongoing government efforts and updated regulations are crucial for managing and safeguarding India’s coastlines.