Spatial distribution and hydrographic characteristics analysis in detached bays of the tetyushsky reach of the kuibyshev reservoir

Abstract

The creation of the Kuibyshev Reservoir led to the formation of numerous bays, a significant por tion of which underwent complete or partial isolation from the main water area. That resulted in a new natural-anthropogenic element in coastal landscapes. The aim of this work was to analyze the spatial distribution and morphometric parameters of isolated bays within the water area of the Tetyushsky reach of the Kuibyshev Reservoir. For the analysis, satellite imagery from Google Earth and Sentinel-2, as well as field research data from 2024, were utilized. Computations were performed in QGIS 3.28.3 GIS for the summer low-water period of 2024 at a normal water level of 52.7 m BS (Baltic System). The study identified 103 detached bays with a total water surface area of 246 hectares. The majority of the bays were located on left-bank islands formed after the flooding of the reservoir bed. Based on water surface area, they were classified as "small water bodies", characterized predominantly by oval and near-circular shapes and slightly indented shorelines. The dynamics of the water surface area showed the trend toward reduction, particularly for bays not connected to the main water area during the flood period. The significance of those findings was underscored by the location of the study objects within the territory of the "Spassky" Biosphere Reserve and the buffer zone of the UNESCO World Heritage Site - historical and archaeological complex of Bolgar.