Features of water balance in the Selenga and Onon river basins during the formation of rain floods

Abstract

Floods are characterized by non-periodic and short-term rise in the water level in the river, which can lead to catastrophic consequences and large material damage. The aim of this work is to study in detail the components of the water balance of the river basin, which affect the amount of flood runoff. The objects of study are the rivers of Eastern Siberia Selenga and Onon rivers. For the work, materials of long-term observations of the hydrometeorological network of the Trans-Baikal UGMS were used, as well as the database of the GPCC atmospheric precipitation climatology center. The methodological basis was a comprehensive hydrological and geographical analysis of the processes of flood runoff, namely the water balance method. In the course of the study, a geographical analysis of the factors of floods in the conditions of the steppe, forest-steppe and taiga zones of Eastern Siberia was carried out. For a thirty-year period of hydrometeorological observations in the basins of the Selenga and Onon rivers, graphs of changes in water discharge over time (hydrographs) were constructed and genetically related values of flood runoff and flood-forming precipitation were calculated. The unity of landscape characteristics and climatic features determine the hydrological indicators of the river in its different sections, which gives an overall picture of the hydrological indicators of the river network as a whole. According to the ratio of the maximum discharge of water of various origins, spring floods and summer floods, in the basin of the river Selenga and Onon groups of rivers were identified according to the prevailing origin of maximum flow. For the rivers of the Selenga and Onon basins, fluctuations in river runoff and atmospheric precipitation were investigated, and their relationships with the characteristics of atmospheric circulation were established. Difficulties in the analysis of hydrometeorological processes for the considered river basins are their transboundary location.