THE INFLUENCE OF FISH-TAIL GROYNES (OR BREAKWATERS) ON THE CHARACTERISTICS OF THE ADJACENT BEACH AT LLANDUDNO, NORTH WALES

Three Fish-tail groynes or breakwaters of rock rubble construction wer e installed during 1991 on the West Shore at Llandudno, North Wales as part of a coastal protection programme. This study considered the eff ect of the northern (Gogarth) breakwater on the adjacent beach. It was found that while the breakwater appears to be effective in protecting the sea wall forming the coastline behind, it has not been successful in increasing beach levels, as proposed, and has also resulted in the accumulation of a large amount of fine material in its lee which redu ces its appeal to recreational users. From this study it is believed t hat beach levels at the site are controlled by the tidal flows across the beach, particularly by the scouring effect within the adjacent Nor th Channel, which prevents the normal beach profile being attained. Th e build up of fine material is due to the quiescent conditions behind the breakwater, however, it appears that the conditions created are fa r calmer than anticipated at the design stage.