NEWS – In a bid to resolve the extensive coastal erosion in Poonthura region in Kerala, the irrigation department is all set to construct eight groynes at a cost of Rs 17.5 crore.

GROYNES

• Definition: Groynes are active structures extending from the shore into the sea, usually perpendicular or slightly oblique to the shoreline.
• Materials: Typically made of wood, rock, or sometimes concrete and metal.
• Purpose:
  • Trap sediment.
  • Dissipate wave energy.
  • Restrict the transfer of sediment away from the beach through longshore drift.

Longshore Drift

• Cause: Occurs when prevailing winds blow waves across the shore at an angle, carrying sediment along the beach.
• Prevention: Groynes prevent this process, thereby slowing erosion at the shore.

Advantages of Groynes

• Easy to construct.
• Long-term durability.
• Low maintenance.
• Reduce the need for beach nourishment and sand recycling.
• Leads to beach widening.
• Reduces erosion.
• Increases wave energy dissipation.
• Serves as a robust structure for long-term coastline stabilization used for societal activities.