The Hel Peninsula is a 35 km long spit that extends into water depths of almost 60 m. Unlike most sandy barriers, the distal end of the Hel Peninsula is prograding into the deep water. This affects unique conditions for the evolution of this section of the Peninsula. The aim of this study is to determine the morpholithodynamic changes on the tip of the Hel Peninsula. Shore studies were performed in 2006-2008 and 2012. Measurements included: beach profiling, determination of shoreline and dune base line positions, and collection of sediment samples. The different nature of the eastern, central and western part of the Hel tip is evident. The eastern part is accumulative, the central part is variable with the general nature of strong and differently directed redeposition and accumulative periods, while the western part is highly erosive.
Submerged breakwaters (SBWs) were used for the first time on the Polish coast in 2006, in the western coast of Gdańsk Bay, in the area of Orłowo Cliff. They were built to prevent the abrasion and inundation of areas situated in the hinterland, especially in the conditions of storm surges. The main objective of the study was to determine their effect on the morphology and grain size composition in the seashore and nearshore zone. Based on the conducted research and analysis, it has been found that the construction has a minor impact on the modification of the shore and nearshore zone morpholithodynamics, which is evidenced by a sinuate shape of the shoreline and a relatively stable cape in the central part of the area, present both before (1966–2005) and after SBWs were built. Furthermore, the progressive abrasion, the lack of significant changes in the morphology and particle size distribution of the beach and the nearshore zone, as well as the fact that those changes are limited only to the immediate surroundings of the submerged breakwaters prove their neutral impact.
The paper presents results of a study of near-bottom currents, lithology and morphodynamics on the shore-zone of the Vistula Spit in Russia and on the western shore of the Sambian Peninsula. The measurements were conducted in 1991 and during the period of 2005-2009. The study involves the analysis of the synchronous and statistical parameters of the currents together with wind, grain-size and sorting coefficient distributions for the deposits of the beach and underwater slope, and also the analysis of the morphology and morphodynamics along the east coast of the Gulf of Gdańsk. It has been shown that under conditions of an acute angle between the seaward wind vector and the coastline the strongest and the most stable longshore currents are formed. An increase of the angle leads to a decrease of velocity and stability of these currents. Under conditions of the wind normal to the shore (90°) in the sector of the curved coast Yantarny - Baltiysk (west wind), convergence of the currents is observed. The assessments of annual capacities of the longshore sediment transport for the coastal segment at the Sambian Peninsula and the deformation volumes on the underwater slope at Baltiysk are summarized. A hypothesis is proposed that the sector of 5-15 km north of Baltiysk under the existing wind-wave conditions is the zone of convergence and the discharge-resulting sediment transport. The assumption of the prevalence of migratory and whirl circulations along the shore zone of Vistula Spit is put forward. It is noticed that entrance moles of Baltiysk considerably impact on parameters of the currents and flow of deposits along the coastline at the length of 3-4 km.
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