Using Remote Sensing Methods of Underwater Studies to Identify Elements and Simulate the Structure of Bottom Landscapes in the Haukaisenlahti Bay (Kuhka Island, Lake Ladoga)

Abstract

The article presents the results of studies of bottom landscapes carried out with the use of an echo sounder with a side-scan location function and supplemented by video filming from an underwater vehicle in a bay of one of the islands in the northern skerry area of Lake Ladoga in June 2022. The results of the echo sounding were used to develop a three-dimensional bathymetric model of the examined Haukaisenlahti Bay on Kukhka Island and to identify significant differences in comparison with published navigation maps for Haukaisenlahti Bay. The formation of the bed topography and the state of the shores in both above-water and underwater zones are determined by the specific features of the geological structure of this part of the water area, resulting from the different resistance to weathering processes in different geological formations. Six main types of facies were identified in the underwater landscape of the bay. The outlook and the change of facies are associated with the presence of hard rocky surfaces and hard clastic material followed by loose soils at greater depths. The outlook of the facies is also determined by the specific features of the bathymetric structure of the bay and the predominance of various associations of living organisms, the development of which depends on the type of surface and soil. The study confirmed the prospects of the use of echo sounders with a side-scan location function to study and map underwater landscapes of Lake Ladoga in combination with a remote video recording from an uninhabited vehicle.