Analysis of the components of the water balance of river basins during the formation of the Selenga and Onon rivers

Abstract

The purpose of the study is to study in detail the components of the water balance of the river basin that affect the amount of flood runoff. The objects of the study are the rivers of Eastern Siberia – Selen-ga and Onon. The work is based on the materials of standard long-term observations of the hydrometeorological network of the Trans-Baikal UGMS, and the databases of the GPCC Center for Atmospheric Precipitation Climatology were used. Relevance. Floods are characterized by non-periodic and short-term rise in the water level in the river, which can lead to catastrophic consequences and major material damage. The methodology of the study consists in a complex hydrological and geographical analysis of the processes of flood runoff, namely, the method of water balance. In the course of the study, a geographical analysis of flood factors in the conditions of the steppe, forest-steppe and taiga zones of Eastern Siberia was carried out. During the thirty-year period of hydrometeorological observations in the basins of the Selenga and Onon rivers, graphs of changes in water flow over time (hydrographs) were constructed and genetically related values of flood runoff and flood-forming precipitation were calculated. The combination of landscape characteristics and climatic features determines the hydrological indicators of the river in its various sections, forming a general picture of the hydrological indicators of the river network as a whole. Conclusions. According to the ratio of the maximum water flow rates of various origins, spring floods and summer floods in the Selenga and Onon river basins, groups of rivers were identified according to the predominant genesis of the maximum flow. For the rivers of the Selenga and Onon basins, fluctuations in river flow and atmospheric precipitation are studied, and their relationships with the characteristics of atmospheric circulation are established. Both rivers under consideration are transboundary, which imposes certain difficulties on the ability to solve problems of determining and predicting hydrometeorological processes.