Coastal defence by natural buffers
Topic: Natural Hazards and Disaster Management in India · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
Natural features along the coast can protect it from storm waves and tsunamis.
- Offshore bars, which are ridges of sand in the sea parallel to the shore, are the first line of defence.
- Barrier islands, beaches and sand dunes come next.
- Mangroves, which are salt-tolerant trees with tangled roots, form the last line.
Each layer absorbs some of the waves' energy before they reach settlements. If these buffers are dug up, levelled or cleared, the coast is left open to damage. The CRZ (Coastal Regulation Zone) Notification 2019 limits building near the shore partly to protect them.
Example
During the 2004 Indian Ocean tsunami, areas behind the Pichavaram and Muthupet mangroves on the Tamil Nadu coast suffered less damage than open stretches nearby.
Don't confuse with
- Embankments and dykes: these are walls that people build to keep water out. Natural buffers are landforms and plants that soak up the waves' force.