Ecological Systems and Devices Annotation << Back THE FLOOD IN YALTA IN THE SUMMER OF 2021 AND THE SUBSEQUENT EVOLUTION OF THE NATURAL AND MAN-MADE PART OF RIVERBEDS B.I. Korzhenevskiy The considered central part of the Greater Yalta (without administrative settlements) is located at the foot of the Crimean Mountains, mainly within the low mountains, and is limited from the west by the watershed surface of Mogabi Hill, from the east by the slopes of the Nikitsky watershed. The source of significant domestic disasters for the town were two small rivers Vodopadnaya and Bistraya. These are small watercourses with a length of less than 10 km with even smaller tributaries and an average annual flow rate not exceeding 0.3–0.6 m3/sec. More than a century ago, both watercourses were equipped with stone banks made of local limestone. Over time, the height of man-made river sides increased, and rubble-concrete thresholds were arranged in the channel and the bottom was concreted. As a result of the abnormal flood in June 2021, the destruction of the sides and the technogenic part of the riverbeds occurred, the destruction of communications located at different heights from sediments, the fall of several cars into the channel and their subsequent destruction, the overfl ow of the stream with entrained sediments over the sides and bridges and the deposition of a considerable amount of alluvial deposits on town streets and other negative phenomena. During the following time, work was carried out to restore the destroyed objects. The mode of evolution of the channel part within the technogenically modified part of them in connection with the ongoing work against the background of the natural flow regime imposed a certain specifi city on the evolution of watercourses and beaches. Keywords: flash flood, erosion, technogenic pressure, riverbed processes, removal cones, energy characteristics. DOI: 10.25791/esip.1.2023.1349 Pp. 36-42.