Groynes | 11 Jul 2024

Source: TH

Groynes are low-lying wood or concrete structures which are situated out to sea from the shore. 

• They are designed to trap sediment, dissipate wave energy, and restrict the transfer of sediment away from the beach through longshore drift. 
  • Longshore drift is caused when prevailing winds blow waves across the shore at an angle that carries sediment along the beach. 
  • Groynes slow the process of erosion at the shore.
• They can also be permeable or impermeable, permeable groynes allow some sediment to pass through and some longshore drift to take place. 
  • However, impermeable groynes are solid and prevent the transfer of any sediment. 
• They are very effective at protecting the coastline in the short-term as they are immediately effective as opposed to some longer-term soft engineering methods. 
  • However, they are often intrusive and can cause issues elsewhere in other areas along the coastline.

Read More: Coastal Erosion