Purpose. The study is purposed at determining modern dynamics of the Lake Sasyk bay-bar (Crimean Peninsula) and the impact of the local seawater intake upon the coastal zone based on long-term in situ observations, satellite data and mathematical modeling. The study was conducted in view of the proposed construction of transverse hydraulic structures.

Methods and Results. Regular (2007–2014) and occasional in situ observations of the coastline dynamics at the Lake Sasyk bay-bar were used. The maximum inter-annual oscillations in the coastline locations are shown to be 5.8 m in the sections to the southeast from the transverse structure (seawater intake) and 3.4–7.2 m – in the sections to the northwest. Seasonal variability is significantly higher: the maximum range is 14.6 m in the sections to the southeast, and in those to the northwest – 26.7 m. The wave climate was investigated. The wave reanalysis data for 1979–2022 have shown that the southwestern direction of waves approaching the coast with a frequency exceeding 30% is most probable. The highest waves also come from this direction. The extreme values of wave characteristics which can occur once in n years were obtained. The mean long-term values of storm numbers in the area under study are given depending on their duration. Application of the GenCade integrated lithodynamic model permitted to obtain the estimates of changes in the coastline position in this area on the interannual scales.

Conclusions. The model calculations made it possible to reproduce the main features and trends in changes of the beach width in the area of the structure obtained due to in situ observations. The mean annual sediment flows in the area under study are directed clockwise (to the southeast) that is conditioned by the coastline orientation and the wave climate features. Difference between the mean annual sediment rates at the area boundaries is negligible – less than 4% of the multi-year average. This fact indicates insignificant impact of the structure upon the sediment total transfer to the southeast.