This type of structure is built perpendicularly to the shoreline extending into the lake. It consists of a structure similar to an offshore breakwater, connected to the shoreline by fill called a groyne. The groyne is combined with a beach area made of fill or cobbles that extends on either side. The protection offered by the groyne helps retain the beach and allows a variety of beach material to be used.
These structures are very effective at shoreline stabilization and have been used regularly throughout the GTA.
However, based on a combination of coastal and shoreline conditions, they were not recommended as a preferred option at Ajax Waterfront Park.
*not listed as preferred or recommended in preliminary options
- Potential to create a larger beach area through protection offered by the groynes
- Much easier to maintain as it is adjacent to the shoreline, and failures would be more gradual
- Since the source material can vary for the beach depending on the groyne size, it may be easier and less costly to source and procure materials, although the costs for cobbles is still highly uncertain
- Size of groynes could be significant based on specific site conditions and choice of beach material
- Beach fill material is expected to move around within the individual beach cell
- Potential for material loss from within the beach cell during high water levels
This option is currently not preferred or recommended for any Reaches in the preliminary assessment. It has a rough costing of $24,000/m.