Coastal erosion processes in the eastern Gulf of Finland and their links with geological and hydrometeorological factors

Potential reasons for the drastic intensification and step-like nature of coastal erosion in the Neva Bay area (to the east of the cape Peschany―Lebyazhye line), the easternmost part of the Gulf of Finland, are analysed based on field observations and hydrometeorogical data from adjacent areas. Beaches in this area consist of easily erodible Quaternary deposits that evolve under overall sediment deficit and are relatively vulnerable with respect to changes in the external forcing factors. It is demonstrated that the most extreme erosion events occur when high waves excited by long-lasting western or south-western storms attack the coast during very high storm surges in the absence of stable sea ice. Since 2004 the frequency of occurrence of such combinations has increased mostly owing to, late freezing of the bay and an increase in the number and severity of extreme erosion events in the future is likely. The coasts are also under gradually increasing anthropogenic pressure. Submarine mining operations in the nearshore and construction of large-scale coastal engineering structures such as the Flood Protection Facility may have considerable impact upon the coasts.