Longshore Sediment Transport Modelling: An Application to Ordu

To simulate the long-term evolution of the beach of Cumhuriyet and Turna Suyu (city of Ordu) located at the Black Sea coastline of Turkey in response to imposed wave conditions and coastal structures, numerical model GENESIS (GENEralized Model for SImulating Shoreline Change) has been applied. The accurate modeling of shoreline change requires calculation of the nearshore waves using the actual bathymetry. As the external wave propagation model, the numerical model POTCAL-2 has been used. In POTCAL-2, the extended mild slope equation has been used to simulate refraction, diffraction, shoaling, reflection, bottom friction, breaking energy dissipation with nonlinear wave celerity and group velocity. Since wave model includes diffractive effects produced by an irregular bottom, it reduces the caustic generation as well as provides better accuracy than the pure internal refraction model of GENESIS. POTCAL-2 places values of wave height and direction at grid points on a nearshore reference line. From this line the internal wave model in GENESIS brings waves to breaking. Shoreline effects of eight offshore breakwaters proposed by Turkish Ministry of Transport and of alternative coastal protection structures are discussed.