In front of the feared Atlantic swell, the town of Ada is threatened by the sea. Every year, the sea takes more than 1.5 m from the coastline, where several buildings are washed away every season. The never ending erosion called for human intervention in order to save Ada. That is where the ministry of Water Resources, Works, and Housing of Ghana took the initiative to set up a major coastal protection project.
The coastal protection works at Ada consisted of the construction of seven groynes between 150 m and 94 m long, built at an interval of 700 m. The part of the groynes that were constructed onshore, were buried after the area was backfilled to the initial level.
The groynes were built in the dry, using dry earthmoving equipment. This required the construction of cofferdams, which served three purposes.
Since the groynes were built in the surf zone, where the swell, tides and currents are serious impediments, cofferdams are simply necessary to allow excavation and leveling of the seabed. Moreover, they facilitate the installation of the different specified rock layers.
Finally, they are useful to protect the land against flooding during these operations. In order to move dry earthmoving equipment around, temporary jetties were built.