Spatial characteristics of washovers formed in the coastal zone of the semi-enclosed tideless sea basin, Gulf of Gdańsk, Baltic Sea

Storm surges lead to coastal erosion but may also leave geomorphological effects that contribute to a positive sediment budget and become a permanent or temporal part of the coastal landscape. We have investigated two study sites in the coastal zone of the Gulf of Gdańsk to examine depositional storm-induced landforms. We have measured and analysed the spatial characteristics of 244 washovers formed between 1979 and 2022. Spatial parameters like length, width, area, and perimeter of individual washovers were derived from orthophoto maps and aerial images with spatial resolution of ~0.2–1m. For the years when DEM was available for two consecutive years, the deposit volume was calculated by subtracting the DEM of the preceding year from the examined DEM. Collected data fills the gap in the knowledge of spatial characteristics of the smallest washovers, commonly forming during the relatively less powerful storms occurring in the Gulf of Gdańsk in comparison to coasts directly exposed to hurricanes or typhoons. Based on our results and data available in the literature, new scaling formulas were delivered for area-to-length, area-to-volume, and length-to-volume washover relationships. The current study indicates that spatial parameters of washover follow most of the relationships described in previous studies. However, it also suggests a more diverse view of different coastal settings impact on the formation of storm-induced landforms. The collected dataset also shows ambiguous data distribution for the smallest mapped features, indicating the influence of acquisition methodology on the data homogeneity and measuring error.