RELIEF AND SEDIMENTS OF THE CONNECTING CHANNEL TILIGULSKYI LIMAN – BLACK SEA

Abstract

Problems Statement and Purpose. Tiligulskyi liman is located in the northwestern part of the Black Sea between the Odessa bay and the Berezansky liman. Operation and reconstruction of the connecting channel influence the geosystem of the estuarine part of the Tiligulskyi liman. Now the channel operates not reinforced and its relief changes dynamically influenced by the combination of natural and anthropogenic factors. Monitoring changes will make it possible to predict how the anthropogenic factors impact to reserved coastal landscapes. The main goal of the research – to find out morphological and morphometric characteristics of the relief’s current state and to define granulometric composition of sediments of the connecting channel Tiligulskyi liman – Black Sea in conditions of artificial regulation of water exchange. Data & Methods. Field studies were carried out at the Tiligulskyi liman sand bar on 5 areas in 2020 and 2021. Performed: depth measurements, GPS coastline mapping, water and sediment sampling. Based on the field studies results the following was determined: В – width, F – cross-sectional area, Нmax – maximum depth, Нavg – average depth, χ- wetted perimeter. Fifteen sediment samples were taken from the elements of the channel’s relief. Granulometric coefficients are determined by the graphical method of PD Trask and by statistical methods. Results. Functioning unforced connecting channel Tiligulskiy liman – Black Sea in conditions of artificial regulations of water consumption, periodical admission of sediment from liman and sea areas against the background of hydrometeorological factors leads to significant linear and vertical deformations of the canal relief. Because of it’s significant length morphological processes are different at each location. Morphological characteristics of connecting channel Tiligulskyi liman – Black sea is highly different in depends of water level. When water level rises on 0.6 m – B, Havg, χ gets higher twice, Hmax – 4 times, and F – 5 times. Current sediments of connecting channel presented as small sand particles and fine to medium sandy granulometric varieties. Prevalent fraction size in all samples is 0.1–0.25 mm. Calculated by V. N. Goncharov’s formula non-blurring sediment speed increases from 0.26 m/s (at canal depths 0.2) to 0.41 m/s (at canal depths 2.0 m), that leads to significant relief deformation during its operation. Channel operation time, during which it’s characteristics will return to its natural condition will approximately 20–25 years. According this, canal should involve deep reconstruction for every 10–15 years without current repair works for maintaining the design parameters.