During the expedition, comprehensive studies of the Central Caspian coastal reservoir were carried out. As a result of the work performed, new data on the spatial distribution of hydrological and hydrochemical parameters of offshore waters were obtained. Hydrological measurements during the expedition were carried out at 17 stations and included measurements of vertical temperature profiles, electrical conductivity from the surface to the bottom using the SBE SeaCat 19plus probe. The Working Group selected samples from 14 points on the water surface for hydrochemical analyses with measurements of wind direction and speed, atmospheric pressure and temperature. The working group analyzed the samples and made its conclusions by comparing the data.