Regional Features of Formation of Ion Runoff in the Northern Dvina Basin

The article presents the results of assessing the long-term variability of the chemical composition of river waters and ionic runoff in the Northern Dvina River basin. Natural and anthropogenic factors of formation are considered and it is shown that conditions of excessive moisture, cold climate and well-washed podzolic soils led to the formation of waters with low mineralization and a predominance of hydrocarbonates and calcium ions in their composition. The intense anthropogenic impact in the Northern Dvina River basin is due to the presence of a developed forestry complex and the Arkhangelsk agro-industrial agglomeration. The variability of water mineralization and the content of major ions in the river waters of the Northern Dvina River basin appears both along the length of the river itself and between the main tributaries. The highest average long-term values of water mineralization are observed at sections of the Northern Dvina and Vym Rivers, and the lowest one characterizes the Vychegda and Sysola Rivers. Water quality violation in terms of the content of macrocomponents in water occurs sporadically and only in case of maximum concentrations of sulfates (up to 4.0 MAC). The variability of ion runoff is characterized by spatial heterogeneity, and the highest values of runoff modules are typical for a particular River Vym catchment. At the same time, hydrocarbonates and sulfates entering the river network make a major contribution to this variability due to the processes of leaching and washout from the catchment area. The presented results can be used in the development of environmentally sound nature protection measures aimed at improving the environmental situation in the Northern Dvina River basin.