This paper presents the results of studies of the physical processes observed in the coastal zone of the eastern part of the Gulf of Gdańsk, from the Vistula river mouth (Poland) to Cape Taran (Russia, Kaliningrad Oblast), because it is under severe environmental and anthropogenic pressure. We present investigations of wind climate, wind-driven currents, deep-water waves, nearshore sediment fluxes, engineering activities, and shoreline changes/response at eight study sites selected along the coast of the study area. Four of the sites are located on the Polish side and four on the Russian side of the state border. An assessment of the anthropogenic impact on coastal litho- and morphodynamics (local sediment fluxes and shoreline response) as a function of different local hydrodynamic climates is performed. Key coastal locations in the Gulf (the Vistula river mouth, the Baltijsk Strait with the harbor of Baltijsk, and the mining plants near Jantarnyj), where natural sediment morphological processes h...

The relationship between the effectiveness of groins and their technical condition was studied. The supporting role of groins in artificial shore nourishment was tested using the theoretical modeling of hydrodynamic and morphodynamic processes in the nearshore zone. This modeling scheme was developed as to represent the actual coastal situation occurring on the shores of the Hel Peninsula (the Gulf of Gdańsk, the southern Baltic Sea). Based on the results of computations and the results of field observations, recommendations were prepared on the design and maintenance of groins. The second part of the paper is devoted to submerged breakwaters. The theoretical modeling of wave-current fields near the segmented submerged breakwaters led to the determination of coefficients of wave transmission and rip current velocities, which finally yielded a piece of design advice. In all numerical simulations, the Delft3D software was used.

The paper presents results of field and theoretical investigations of a natural sandy shore located near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly by breaking. The main field data comprise offshore wave parameters and three cross-shore bathymetric profiles. Waveinduced nearbed velocities and bed shear stresses are theoretically modelled for weak, moderate, strong and extreme storm conditions to determine sediment motion regimes at various locations on the seaward boundary of the surf zone. The paper contains a discussion on the depth of closure concept, according to which the offshore range of sea bottom changes can be determined by the extreme seasonal deep-water wave parameters.

The paper deals with the sandy coastal zone at Lubiatowo in Poland (the south Baltic Sea). The study comprises experimental and theoretical investigations of hydrodynamic and lithodynamic processes in the coastal region located close to the seaward boundary of the surf zone and beyond the surf zone. The analysis is based on field data collected at the IBW PAN Coastal Research Station in Lubiatowo. The data consist of wind velocity reconstructed from the long-term wave climate, deep-water wave buoy records and sea bottom soil parameters. Nearbed flow velocities induced by waves and currents, as well as bed shear stresses are theoretically modelled for various conditions to determine sediment motion regimes in the considered area. The paper discusses the possibility of occasional intensive sediment transport and the occurrence of distinct sea bed changes at bigger water depths.

The paper deals with the influence of the wave shape, represented by water surface elevations and wave-induced nearbed velocities, on sediment transport under joint wave-current impact. The focus is on the theoretical description of vertically asymmetric wave motion and the effects of wave asymmetry on net sediment transport rates during interaction of coastal steady currents, namely wave-driven currents, with wave-induced unsteady free stream velocities. The cross-shore sediment transport is shown to depend on wave asymmetry not only quantitatively (in terms of rate), but also qualitatively (in terms of direction). Within longshore lithodynamics, wave asymmetry appears to have a significant effect on the net sediment transport rate.

In this paper, we present a simple theoretical method of determining the optimal groin length on a sandy multibar shore of a nontidal sea. Example computations for the seashore of the Hel Peninsula (Poland, south Baltic Sea) are provided. The proposed unsophisticated method, which consumes little time and is thus innovative, is based on calculations of the mean annual sediment transport rate and a determination of the width of the surf zone. The reliability of the theoretical modeling results was demonstrated, as well as their compatibility with the features of the groin system designed and constructed along this stretch of the shore a few decades ago. Long-term field observations in the village of Kuźnica have shown that such a system effectively supports and supplements the artificial shore nourishment in the considered region. The method can be applied to other sandy and multibar shores of nontidal seas.