This beach in Salthill, which gets battered by strong Atlantic Storms, is here because of beach accretion. This process is further enhanced by human factors, in the case of the posted coordinates, groynes. Take note that this EC can be done throughout most of the Salthill Promenade.

Be aware that wading into the water may be required to obtain some of the answers.

Groynes

Groynes are a hard engineering solution for beach management. Groynes serve 2 purposes, depending on their construction method.

1. Prevent coastal erosion, particularly from longshore drift.
2. Help beach accretion. This can be done by building a shorter groyne pointing slightly downstream, and a longer groyne to trap the sediment.

Groynes can be classified on their material and function.

• Material
  • Not much explanation needed here. Wood, rock, sandbag, etc. Is it can be used to build a skyscraper, it sure can be used to build a groyne.
• Shape
  • I'll let the image below do most of the talking.

• Permeability
  • Permeable and Non-Permeable. Permeable groynes reduce the flow, whereas the other completely blocks it. If there are gaps between the building material, the groyne is permeable.
• Submersed
  • ​​​​​​​Above/Under Water

Logging Tasks

Send the answers to the following via the message centre. 

1. Identify the type of groynes used by
   • Material
   • Shape
   • Permeability
   • Submerged/Not Submerged
2. Are the groynes perpendicular to each other? What effect does this have on beach accretion?
3. From Palmers Beach to Blackrock Beach you will see multiple beaches between the groynes. Take note of the alignment of the sands of any of them and suggest a direction that the groynes trap sediment.
4. What are the negative side effects of the groynes that you can see or think of?