Relief-Forming Role of the Ice Factor in the Coastal Area of the North-West Part of the Black Sea

Abstract

Purpose. To define the role of the ice factor in morpholithodynamics of the coastal area of the North-West part of the Black Sea. Methods. Field and in-office research was carried out in the North-West part of the Black Sea during the winter seasons of 2005-2019. The research work included geometrical leveling of the beach and the surface of shore-fast ice, drilling of the ice layer, depth sounding, sampling of deposits and of an ice core. The content of deposits in shore-fast ice was determined by weighting them after melting and evaporating a known volume of an ice core. Results. Formation of shore-fast ice, ice and hummock ride-ups, freezing of the surface of accumulative forms, congelation of fast ice with the beach surface and the bottom, freezing into ice of deposits thrown on the surface of fast ice, formation of meltwater runoff channels, melted deposit banks, melt holes had been observed. Shore-fast ice in Odesa Bay was 1.0 to 1.6 meters thick. Hummocks 0.8 to 2.3 meters high were formed. The average content of deposits in shore-fast ice in Odesa Bay was 15.7 g/m2 to 111.5 g/m2. Within the protected water area of Odesa coast protection complex, the thickness of ice was 0.5 m. Repeated measurements revealed a temporary accumulation of deposits at the depths of 1.5 to 2.0 m at the distance of 30-40 m from the water edge. The average content of deposits in shore-fast ice within the protected water area was 186.5 g/m2. The thickness of ice on the surface of beaches on the open shore was 0.2-0.5 m. Banks of sand and gravel-pebble deposits between 0.4-0.8 m and 1 m high and with the volume of 1.2-1.4 m3/m were formed on the frozen beach surface by onshore flow and storm overwash. Conclusions. In the North-West part of the Black Sea, the impact of the ice factor is characterized by rhythmic observation during severe, moderate and warm winter. Generally, it hasn’t significant impact. In somelocal points during cold winter may results in a significant alteration of the relief and deposits, and causes damage to hydraulic structures. Ice gets saturated with deposits mostly when submerging to the bottom during ebbing, when contacting the beach, being carried directly onto its surface and along cracks, and during aeolian movement. For artificial beaches of Odesa coast protection complex, the average content of deposits in ice is defined by peculiarities of formation of shore-fast ice and by hydrodynamics of the water area of these coast sections. The shapes of relief, formed under impact from the ice factor, are minor; they exist for the duration of its impact, and disappear after the storm ends.