Modeling the Dependence of the Area and Volume of Posolsky Bay from the Level of Lake Baikal

The article is devoted to the issues of regulating the level of Lake Baikal and assessing its consequences. Posolsky and Maly bays of Lake Baikal are of great fishery importance. It is here that the larvae of the omul of Posolsky population feed themselves. The survival of juveniles depends on fluctuations in the areas and volumes of these reservoirs. The purpose of this study is to determine the dependence of the areas and water bodies of the Posolsky and Maly bays on the level of Lake Baikal. To achieve this goal, the tasks of choosing indices for determining the coastline from Sentinel-2 satellite images, processing the initial data, calculating the areas of reservoirs at different levels of Baikal, estimating the model parameters and using it to build a digital elevation model (DEM) were set and solved. A number of indices for determining the boundaries of a reservoir are considered, and the NDWI index is chosen based on the overall accuracy and Cohen's kappa coefficient. With the help of the DEM, the volumes of reservoirs were determined. The obtained dependencies allowed us to conclude that at the level of the lake. Baikal, within the limits of 456.2-456.8 m of the Pacific height system, slight changes in areas and volumes are observed, which can be considered safe for the survival of omul juveniles. The most critical changes occur when the lake level drops below 456.0 m and exceeds 457.0 m. The results obtained will make it possible to make more informed decisions on lake level regulation.