Alongshore Sediment Transport in the Eastern Baltic Sea

Jankowski, M.Z.; Soomere, T.; Parnell, K.E., and Eelsalu, M., 2024. Alongshore sediment transport in the eastern Baltic Sea. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 261-265. Charlotte (North Carolina), ISSN 0749-0208. The shores of the almost tideless Baltic Sea evolve under the joint impact of surface waves and water level. We identify the basic transport patterns and zones of sediment accumulation and erosion in the eastern Baltic Sea based on the analysis of alongshore and temporal variations in the potential bulk and net alongshore sediment transport. The area covered extends from Cape Taran on the Sambian Peninsula to Cape Kolka at the entrance to the Gulf of Riga. ERA-5 model winds for the period 1996–2022 are employed to produce time series of significant wave height, wave direction and periods using the SWAN model, at a coastal grid resolution of 560 m and a time resolution of 1 h. Sediment transport rates are subsequently calculated with the CERC formula. The basic counterclockwise pattern and most probable areas of accumulation and loss of sediment correspond well with previous findings. The use of much higher spatial resolution makes it possible to add further details to the locations of convergence and divergence zones of sediment transport, such as the divergence zones north of Klaipėda and to the south of Cape Akmenrags. The calculations confirm the surprisingly high rates of net sediment transport that have been reported for some areas, particularly to the southwest of Cape Kolka (up to 700,000 m3/yr). This transport continues towards the south-eastern bayhead of the Gulf of Riga that serve as an end station for most of sand.