PECULIARITIES OF FLOODS ON THE TERRITORY OF POKUT CARPATHIANS

Abstract

The article analyzes the peculiarities of floods in Pokut Carpathians. It is determined that the main causes of floods are the amount and intensity of precipitation, features of geomorphology and hydrography of the study area. The peculiarities of the geomorphological structure of the territory, the differences of geomorphology between the middle and low mountain parts of Pokut Carpathians are found out. The middle mountains are characterized by significant vertical and horizontal dissection of the terrain, the predominance of narrow and deep river valleys, the presence of large catchments in the upper reaches of rivers. The lowlands are represented by symmetrical ridges with wide ridges, steep and sloping slopes, which are divided by relatively wide river valleys. Determining the steepness of Pokut Carpathian slopes, it was found that steep and very steep slopes occupy more than 18% and are located in the upper reaches of rivers, and steep slopes occupy almost half of the study area and this criterion increases the possibility of sudden floods. Analyzing the geomorphology of Pokut Carpathians, it was found that the formation and development of floods largely depends on the geomorphological features of the territory. The dependence of floods on the hydrographic features of rivers and their basins has been established. It has been found that rivers are characterized by a branched river system in the upper and middle reaches, and the lower reaches are mainly one artery, where all the water accumulates during floods. In addition to the above-mentioned, the formation and development of floods are also influenced by soils, which in mountain conditions are formed on hard geological rocks and are often poorly permeable and have a small depth of soil profile, which in turn do not absorb much moisture. As for the forest cover of the study area, it is determined that it is more than 57 %, but even such a percentage of forests in the event of a sudden and large rainfall can not contain excess water. We present the results of meteorological indicators, including rainfall and heavy rains over 15 years, at two observation points- Variatyn Hydropower and Hutsulshchyna National Nature Park Meteorological Posts. It was found that heavy floods usually occur in June-July, the amount of precipitation at VariatynHydropower Plant is always higher than at Hutsulshchyna NNP meteorological point. After analyzing the course of intense rains over fifteen years at two observation points, it was determined that VariatynHydropost is characterized by heavy rainfall more often than Hutsulshchyna NNP meteorological point. According to the analysis of the data of VariatynHydropost and Hutsulshchyna NNPMeteorological Station for the period 2005–2020, 65 and 53 days were recorded, respectively, with heavy rains. It has been studied that the greatest and largest floods during the observation period in Pokut Carpathians were recorded on Cheremosh, Chornyi Cheremosh, Rybnytsia, Pistynka, Liuchkarivers on July 24–28, 2008, July 7–8, 2010 and June 23, 2020.