The key elements of this option are:
The recharged shingle beach and timber groynes of this option are identical to those of Option 1 and will employ similar construction techniques. For this third option, however, low crested offshore rock breakwaters will be used to the eastern part of the frontage in place of the groyne rock heads and breastwork.
Offshore breakwaters work by intercepting wave energies and causing wave breaking before the waves impact on the beach. The purpose of this action is to limit beach response under storm action. For this reason, breakwaters placed in front of particularly sensitive locations will offer them additional protection and can therefore be used in place of breastwork.
The breakwaters will also modify the sand and shingle transport patterns on the beach behind them. This will lead to the accumulation of finer beach material and the flattening of upper beach slopes. Breakwaters of this type would be constructed of large rocks placed under the low water mark. Importation of the rock would be by ship and they would be carefully placed to ensure stability.
The height of the breakwaters will be confirmed by further design work but is likely to be around mid tide level. At high water they will therefore be submerged and will be carefully marked in consultation with the navigation authorities.