THE INFLUENCE OF WINTER-SPRING TEMPERATURES AND PRECIPITATION ON THE SPRING FLOOD WAVE

The complex influence of meteorological conditions on the first (April) wave of spring-summer flooding of the mountain rivers was studied by the example of 34 mid-size and small rivers of the Altai-Sayan mountain country covering more than 2,000,000 km2 of the Central Asia territory. System-analytical modeling was employed to describe the complex dependence of April river runoff on air temperatures and precipitation for December-April. The impact of factors was quantitatively assessed through solving the inverse mathematical problem and using 1,760 values of river runoff for 1951-2019, meteorological data and carto- graphic information on the relief and landscape structure of river basins calculated in ArcGIS 10.2. Precipitation accumulated in December-March as snow cover had a positive effect on runoff only in case of proximity of winter temperatures to their long-term mean values. At low April temperatures, river runoff increased along with the growth of current precipitation, while at temperature rise it decreased. The established dependencies of the first flood wave on meteorological factors are of great importance for effective preventing adverse effects of spring floods in the mountain regions.