Assessment of water quality in the rivers of northern European Russia by using oxygen demand indices

Analysis of the probability curves of multiyear organic content data and water colour indices of the rivers located in the northern part of European Russia (the Northern Dvina, Pechora, Onega, and Mezen) allowed revealing seasonal patterns of hydrochemical indices. Water quality for different seasons was assessed. Regional estimates of hydrochemical indices and water quality were obtained. Relations between oxygen demand indices, water colour indices, and water content of those rivers were considered.     

Sedimentation of suspension in the Mozhaisk Reservoir

Sedimentation fluxes of suspension were determined in experimental studies on the Mozhaiskoe Reservoir in summer. The leading factors of formation and the rate of accumulation of sedimentary material and organic mater in the reservoir in different phases of synoptic cycle in the channel and shallow zones of the bed in the central part of the reservoir.     

On Seasonal Alternation of Priority Factors that Control the Rate of Oxygen Consumption by Soils in a Valley-Type Reservoir

Data of long-term studies are used to evaluate the rate of O₂ consumption by soils in the Mozhaisk Reservoir as a function of a number of physicochemical and biological factors. Seasonal variations in the rate of O₂ consumption by the soils and the relationship between these variations and the priority factors are established.     

On the role of hydrometeorological factors in formation of the valley-type reservoir anoxic zone

Based on the multiyear researches of the Mozhaisk reservoir oxygen regime and methods of mathematical modeling, dependence of the anoxic zone formation rate on the hydrometeorological factors was studied. These factors define a degree of the water mass stratification and intensity of the production and degradation processes and, hence, the anoxia development rate.     

Influence of intrareservoir and meteorological factors on the rate of oxygen demand by valley reservoir sediments

Analyzed are the spatial and temporal variations of the sediment oxygen demand rate in the Mozhaisk Reservoir. It is demonstrated that this rate in summer depends both on the sediment characteristics and on the biological and meteorological factors. It is revealed that the content of labile organic substances in the silt is of great importance for the oxygen consumption rate (all other factors being equal). The inflow of these substances to the bottom is regulated by the water column stratification depending considerably on weather conditions. Estimated is the contribution of main organic matter consumers in the bottom sediments.