Assessment of the Abiotic Factors Influence on the Distribution of Zostera in the Internal Bays of Posyet Gulf Based on the Results of Numerical Simulation

In order to explain the spatial nature of the distribution of eelgrass in the inner bays of Posyet Bay, numerical experiments were performed to simulate hydrodynamics and morphodynamic processes. The hydrodynamics was modeled using the Delft3D Flow model. The spectral wave model SWAN (Simulating WAves Near shore) was used to calculate the wind wave parameters (propagation direction, wave length and height, near-bottom orbital velocities). Alteration of coastal zone profile under the impact waves and the hydrodynamic of tidal and wind currents was performed using the Delft3-MOR morphodynamics module included in the Delft3D software package. The results of numerical experiments have shown that the dynamics of the coastal bottom topography is determined by sediment transport forced by combined action of waves and currents. Comparison of the modeling results with information on the distribution of Zostera of previous studies and field surveys data showed a high agreement with model data on the spatial distribution of erosion and accumulation zones in the coastal zone.