Numerical simulation of dynamics of sediments disposed in the marine coastal zone of the south-eastern Baltic

Three dumping sites located at the south-eastern part of the Baltic Sea at shallow depths near the shore of the Sambian Peninsula are considered. The first and second ones are located south and north of the Vistula Lagoon inlet, and are used now for disposing dredged material extracted from the Kaliningrad Seaway Canal. The third dumping site is located near the northern shore of the Sambian Peninsula, east of Cape Gvardeyskiy and assigned for disposing the dredged material extracted from the fairway to the Pionerskiy Port located nearby. All three dumping sites are located either in front of or not far from the eroded segments of the shore. The question behind the study is: Is it possible that disposed material is naturally transported from the damping site to the shore and accumulates there to protect it from erosion? A numerical hydrodynamic transport 3D model (MIKE) was used to model sediment transport under different wind actions. The winds with the speed stronger than 15 m/s wash out disposed material completely from the dumping site and spread it over a wide area with a negligible layer thickness. Winds of about 7–10 m/s transport material along the shore at a distance of a few kilometres; that may be useful for shore protection. Winds with a speed of about 5 m/sec or less do not lead to resuspension of sediments. The first location of the dumping site looks very ineffective for potential protection of the shore nearby. On the other hand, the second and especially the third locations are favourable for the transport of disposed material to the shore; the most favourable conditions are at onshore or alongshore currents.