Syllabus: Geography/Environment
Source: The Hindu
Context: Coastal erosion in Tamil Nadu is increasingly threatening livelihoods and infrastructure due to both natural processes and human interventions.
What is Coastal erosion?
It refers to the loss of coastal land due to the action of waves, currents, and human activities.
Examples:
- Tamil Nadu, with India’s second-longest coastline, faces significant erosion challenges exacerbated by construction projects like groynes, ports, and desalination plants. Groynes, intended to control erosion, often shift the problem to neighbouring areas rather than solving it.
- Chengalpattu: Groynes at Soolerikattukuppam are causing erosion to neighbouring villages.
- Puducherry: A port’s construction led to severe beach erosion, though recent efforts to restore the beach have had mixed results.
Key Findings of the Study Regarding Tamil Nadu Coast:
- Sand Movement: For most of the year, sand is carried from south to north by wind and sea currents; during the northeast monsoon, this flow reverses.
- Impact of Structures: Building ports, breakwaters, or groynes disrupts this natural sand movement.
- Erosion Effect: Sand accumulates on one side of these structures, leading to increased erosion on the opposite side, with waves encroaching further inland and heightening coastal risks.
Causes of Coastal Erosion:
Natural Causes:
- Waves: Powerful waves erode coastlines through abrasion and hydraulic action (e.g., the cliffs of Dover).
- Tides: High and low tides can significantly impact erosion, especially in areas with large tidal ranges (e.g., Bay of Fundy).
- Wind and Sea Currents: Cause long-term erosion by moving sand along the coast; direction reverses during monsoons (e.g., Tamil Nadu coast).
Human Cause:
- Hard Structures: Ports and groynes disrupt sand movement, leading to erosion on the down-current side and accumulation on the up-current side.
- Development Projects: Infrastructure changes, such as land reclamation, worsen erosion by altering the shoreline (e.g., Mumbai).
- Port Expansion: Breakwaters and jetties from expanded ports block sand movement, increasing erosion on one side (e.g., Ennore and Adani Kattupalli Ports).
Challenges:
- Ineffectiveness of Groynes: Often shifts erosion rather than prevents it.
- Regulatory Issues: Lack of proper clearance and adherence to Coastal Regulation Zone rules.
Solution:
- Green belts and artificial reefs help in the mitigation of coastal erosion.
- Coastal habitats such as Mangroves, Coral Reefs, and lagoons are recognized as the best defence against sea storms and erosion, deflecting and absorbing much of the energy of sea storms.
- Hybrid Approach: Combining hard and soft measures like bio-shields and nourishment to better manage erosion.
Government Initiatives to Tackle Coastal Erosion:
- Shoreline Mapping System: NCCR identifies 33.6% of the coastline as vulnerable to erosion.
- Hazard Line: Defined by MoEFCC for disaster management and adaptive planning.
- Coastal Regulation Zone (CRZ) Notification 2019: Allows erosion control measures and sets up No Development Zones.
- Coastal Zone Management Plans (CZMP): States must map erosion-prone areas and prepare Shoreline Management Plans.
- National Strategy for Coastal Protection: Guidelines developed by MoEFCC for coastal states.
- Flood Management Scheme: State and Union Governments plan anti-sea erosion projects.
- Coastal Management Information System (CMIS): Collects coastal data for protection planning; and experimental setups in Kerala, Tamil Nadu, and Puducherry.
- State Initiatives: Tamil Nadu’s response includes building groynes and seawalls, though their effectiveness is debated.
- Using Geosynthetic tubes: currently being used along the coast in Odisha.
Insta Links:
Coastal erosion and landforms thus formed
Mains Link:
The extent and severity of the coastal erosion problem are worsening with global sea level rise. It has both ecological and economic costs and needs to be addressed urgently. Analyse. (250 words)
