Assessment of the filling regime and variability of morphometric characteristics of ponds and reservoirs of small rivers of the steppe zone of Ukraine using data from remote sensing of the Earth (on the example of the Velykyi Kuyalnyk River)

In the paper on the example of 9 artificial reservoirs (7 ponds and 2 reservoirs) in the basin of the Velykyi Kuyalnyk River using the geodetic online tool USGS LandLook and the archive of space images radiometers Landsat 1-8 and Sentinel-2 for the period from 1989 to 2021 defined all the years in which these artificial reservoirs were filled with water or were dry. It was found that the filling of ponds and reservoirs (including those that periodically dried up) occurred during rain floods in spring and summer (sometimes in autumn) for several days (from 2-3 days to 1 week). The results of the study (on the example of Severinov Reservoir) are presented on chronological graphs of variability of the main morphometric characteristics (values of water surface area and length) for the period from 1989 to 2021. It is determined that there is a close unambiguous relationship between the water surface area and the length of reservoir (R2 = 0.997), and the arithmetic mean of the relative deviations does not exceed ±5%. It is recommended to use the above method to establish morphometric characteristics and assess the filling regime of artificial reservoirs according to remote satellite sensing of the Earth during preliminary (reconnaissance) studies and diagnostic monitoring of small rivers. Based on the results of research on the example of the Velykyi Kuyalnyk River, practical recommendations are provided to reduce the existing volume of regulation of runoff of small rivers in the steppe zone of Ukraine. Their implementation will contribute to the future restoration of the hydroecological regime in the Velykyi Kuyalnyk River basin.