Modelling of sediment transport of Akyaka Beach

The long-term evolution of the beach of Akyaka, Gokova Bay (city of Mugla) located at the Southern Egean Sea coastline of Turkey in response to imposed circulation, wave conditions and coastal structures has been numerically modelled. Akyaka Beach is a Specially Protected Area, and located at the East end of Gokova Bay. The main agent of the circulation is the wind shear in Gokova Bay where the tidal range is only in the order of 25 cm. There is a groin at the south and there exists a breakwater at the north of the beach. When the present coastline has been compared with the coastline in 1945, nearly 60 meters of erosion has been observed between these two structures. Currents and longshore sediment transport cause significant shoreline changes along the beach. The current pattern has been modelled numerically by three dimensional baroclinic model HYDROTAM-3D that consists of hydrodynamic, transport and turbulence model components. Sediment transport is modelled by numerical model GENESIS which is a generalized model for simulating the shoreline change. Shoreline change of Akyaka Beach has been analysed under the effects of existing coastal structures and precuations for coastal erosion have been discussed with the help of numerical models. It has been concluded from the numerical study that to prevent the coastal erosion it is necessary to remove the previously constructed groin at the south of the beach. To well understand the hydrodynamics and sediment transport at the site is very important before the construction of any coastal structures.