Forest influence on the thermal, ice and level regimes of rivers of the Ukrainian Carpathians ; Вплив лісу на термічний, льодовий та рівневий режими річок Українських Карпат

The paper presents the results of the analysis of quantitative indicators of water temperatures, ice phenomena and amplitude of river levels for the altitude range of 300-1600 m above sea level. In the course of research, the factors of their formation are found to include the territorial variability of hydroclimatic conditions on two opposite megaslopes of the mountain system and the influence of the height, area and forest cover of the catchments on them. Firstly, it is noted that for the north-eastern megaslope, ice phenomena and flood water levels are on average 1.5 times greater than on the south-western megaslope, and summer water temperatures are respectively lower by 1-3 °C. The indicators of water level growth and summer temperature decrease with increasing area and height of the catchments were calculated. The influence of the forest on the thermal, ice and level regimes of the rivers is highlighted. Moreover, it was found that in all forest vegetation conditions of the region, an increase in the forest cover of water catchments causes a decrease in summer water temperatures, an increase in its winter indicators, a slowdown in the onset of ice damming, its duration, a decrease in ice thickness and a decrease in the amplitude of river runoff. Furthermore, the results of multiple correlation analysis with the calculated empirical dependencies of summer water temperatures, the duration of ice phenomena and indicators of level amplitudes on the height, area and forest cover of 31 catchments of the north-eastern megaslope and 24 catchments of the southwestern megaslope are presented. The tightness of the relationships of the analyzed characteristics of the catchments is quite high (R = 0.75 – 0.95). It is also revealed that the gradients of the forest impact on the reduction of water temperatures on both megaslopes are approximately the same, namely, a 10% increase in the forest cover of watersheds contributes to a decrease in average summer temperatures by 0.3 °C, and average maximum values by – 0.5 °C. A ...