What are Groynes?

July 7, 2024

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.

About Groynes:

These are active structures extending from the shore into the sea, most often perpendicular or slightly oblique to the shoreline.
They’re usually made of wood, rock or sometimes concrete and metal.
They are designed to trap sediment, dissipate wave energy and restrict the transfer of sediment away from the beach through long shore drift.
- Longshore drift is caused when prevailing winds blow waves across the shore at an angle which carries sediment along the beach. Groynes prevent this process and therefore, slow the process of erosion at the shore.
Advantages
- Groynes are easy to construct. They have long term durability and are low maintenance.
- They reduce the need for the beach to be maintained through beach nourishment and the recycling of sand.
- It traps sediment, leading to beach widening, reduced erosion and greater wave energy dissipation.
- It serves as a robust structure (if designed and maintained properly) that can be used for long-term stabilization of coastlines used for societal activities.