Детальные исследования источников питания и механизмов формирования речного стока стали возможными в последние десятилетия благодаря развитию инструментария гидролого-гидро­гео­хими­ческого анализа. С использованием трассерной модели смешения (ЕММА) и данных гидролого-гидрохимических съемок уточнены источники питания реки Велеса в бассейне реки Западная Двина и выполнена их оценка. Источниками питания являются: воды валдайского надморенного водно- и озерно-ледникового водоносного горизонта, болотные воды, атмосферные воды. Продемонстрирован специфический характер их сезонной динамики в период с мая 2017 года по июнь 2018 года. Воды надморенного водно- и озерно-ледникового комплекса – значительная и постоянно действующая составляющая речного стока. Их доля в период весеннего половодья 2018 года составила – 21%, а в периоды, следующие за сходом половодья, их доля заметно выше: в 2017 году – 31%, в 2018 году – 38%. Значительная доля атмосферных вод отмечалась в зимний период 2017 года – до 30%, что обусловлено избыточной увлажненностью водосбора в результате выпадения аномальных жидких осадков и нетипичной метеорологической обстановкой в первой половине зимнего периода 2017 года. Максимальные доли атмосферных вод (до 60%) отмечаются в теплые периоды, после схода весеннего половодья, 2017 и 2018 годах. Предшествующее увлажнение водосбора и осадки в периоды съемок были главными причинами высокой их доли. Атмосферные осадки, поступающие в результате инфильтрации в верхнюю зону аэрации практически без существенной трансформации их химического состава (верховодка), разгружаются в реку подповерхностным путем. Болотные воды преобладали в речных водах во время весеннего половодья – 46%, их доля высока и во время зимнего периода (до 35%), а в периоды начала лета – близки к нулю.

Детальные исследования источников питания и механизмов формирования речного стока стали возможными в последние десятилетия благодаря развитию инструментария гидролого-гидро­гео­хими­ческого анализа. С использованием трассерной модели смешения (ЕММА) и данных гидролого-гидрохимических съемок уточнены источники питания реки Велеса в бассейне реки Западная Двина и выполнена их оценка. Источниками питания являются: воды валдайского надморенного водно- и озерно-ледникового водоносного горизонта, болотные воды, атмосферные воды. Продемонстрирован специфический характер их сезонной динамики в период с мая 2017 года по июнь 2018 года. Воды надморенного водно- и озерно-ледникового комплекса – значительная и постоянно действующая составляющая речного стока. Их доля в период весеннего половодья 2018 года составила – 21%, а в периоды, следующие за сходом половодья, их доля заметно выше: в 2017 году – 31%, в 2018 году – 38%. Значительная доля атмосферных вод отмечалась в зимний период 2017 года – до 30%, что обусловлено избыточной увлажненностью водосбора в результате выпадения аномальных жидких осадков и нетипичной метеорологической обстановкой в первой половине зимнего периода 2017 года. Максимальные доли атмосферных вод (до 60%) отмечаются в теплые периоды, после схода весеннего половодья, 2017 и 2018 годах. Предшествующее увлажнение водосбора и осадки в периоды съемок были главными причинами высокой их доли. Атмосферные осадки, поступающие в результате инфильтрации в верхнюю зону аэрации практически без существенной трансформации их химического состава (верховодка), разгружаются в реку подповерхностным путем. Болотные воды преобладали в речных водах во время весеннего половодья – 46%, их доля высока и во время зимнего периода (до 35%), а в периоды начала лета – близки к нулю. Using the mixing model (EMMA) and hydrological and hydrochemical data, the geographical water sources for the Velesa river were identified and their quantitative assessment was made. They are: valdai super-moraine aquatic and lake-glacial aquifer water, swamp water, atmospheric precipitation water. EMMA-model results demonstrate the seasonal dynamics features of water sources in the period May 2017 – June 2018. Water of the super-moraine and lake-glacier aquifer are significant river runoff component constantly operating during year. Its proportion during the spring flood of 2018 is about 20%; its proportion in the periods following the spring flood is higher – in 2017 – 31%, in 2018 – 38%. Significant proportion of atmospheric precipitation waters is observed in the winter period of 2017 – up to 30%, it is due to excessive humidity of the catchment as a result of abnormal liquid precipitation and non-typical meteorological conditions in the first half winter period of 2017. The maximum proportion of atmospheric water (up to 60%) is occur during warm periods after a spring floods in 2017 and 2018. Antecedent watershed moistening and precipitation during the survey periods were the main reasons for the high proportion value. Atmospheric precipitation coming as a result of infiltration into the vadoze zone without significant transformation of their chemical composition (temporary perched water) is discharged into the river by a subsurface flow path. Swamp water is prevailed in river water during the spring flood – 46%, its proportion is also high during the winter period – up to 35%, and in early summer periods – decline to zero.

In 1958 V.F. Perov, staff member of the Khibiny Research and Training Station of the MSU Faculty of Geography, described four snow-ice formations in the Khibiny Mountains and classified them as very small glaciers. Until our research began in 2005, these glaciers were not studied in detail. We used field observations, drilling, GIS and remote sensing methods to study the structure of the glaciers and evaluate changes in their geometry during 60 years. The snow-ice formations were drilled through for the first time and the ice cores underwent geochemical and isotope-oxygen analyses. The thickness of ice kernels varies from 0,2 to 1,6 m. Our investigations showed that despite a slight degradation, the glaciers` area remains relatively stable since 1958. This fact may be caused by the increase in solid precipitation in recent years. According to the analysis of climatic changes, in the early 2000s a decrease in snowfall was observed in the Khibiny Mountains. The maximum snow thickness at the meteorological site of the Khibiny station in 2002-2003 winter period was 55 cm. This could be a factor of more than 2 times decrease of glacier areas during 2000-2010. After 2007 there has been an increase in snow precipitation, and the maximum snow depth of 180 cm was observed in 2020, the absolute maximum for the whole period of observations (1984-2020). According to published data the increase in mean annual temperature at the plains of the Kola Peninsula is 2,3 ± 1°C during the last 50 years. However, mean monthly temperatures of the summer do not rise. We consider that, along with recently increasing snow precipitation, this is exactly what determine rather stable state of snow-ice formations in the Khibiny Mountains, which appeared to be more resistant to climate warming than mountain glaciers.

Circulation of carbon in water bodies is a fundamental process of the nutrient cycle in water ecosystems. Carbon flux from bottom sediments is currently the least studied chain of this circulation. The aim of this investigation was the study of HCO3 flux from bottom sediments in the valley-type reservoir and identification of their relationship with the hydrological structure of the water column. Fieldwork and laboratory experiments were conducted at the Mozhaisk reservoir in 2017-2019. These years differed in weather conditions, level regime and stability of water masses. Hydrological surveys were conducted three times during the summer period of each year. They included measuring the vertical distribution of hydrological characteristics and sampling of water and bottom sediments. The Kuznetsov-Romanenko tube method was used to study exchange processes. Hydrocarbonate carbon flux from sediments into the water may range widely (50-900 mgC/m2day). By comparing HCO3 flux with the hydrological structure of the water column, it was revealed that in deep (> 8 m) areas, the release of HCO3 depends on the stratification and thickness of the uniform hypolymnion, where seiches and compensation currents may promote transsedimentation from shallow places to the flooded river bed. In areas with a depth of < 8 m, hydrocarbonate carbon flux from sediments depends much more on the autochthonic organic matter produced by phytoplankton. The relationship between HCO3 flux and the content of organic matter in the soil and its hygroscopic humidity is insignificant.

Transboundary rivers are the connecting threads of different states. Hydrological monitoring and water quality control may vary significantly in different countries and leads to difficulties in solving various water management tasks. Trans-border areas require the resolution of a number of special issues, often in the field of interstate relations. This article presents the results of the analysis of hydrological processes monitoring organization in transboundary river basins of Russia and Eastern Europe. The assessment of typical monitoring problems on the example of the Western Dvina river basin under the circumstances of changing population of the territory and legislative framework governing water management is given. From the analysis of the official information sources and field observations, the structure of hydrological observations in the Western Dvina basin in Russia, Belarus and countries of the European Union is compared with their changes over time. Information on the number and density of the monitoring network stations is given, existing standards and documents regulating the procedure of observations, the composition of the measured parameters, the quality of measurements and the availability of monitoring data are compared. The analysis of methods of network observations of suspended sediments in the Western Dvina basin was carried out. The uncertainty of measurements of the concentration of suspended sediments at the outlet in the Russian part of the Western Dvina basin, caused by the existing methods and, thus, typical for determining this parameter on the observation network in the Russian Federation, is revealed. It is shown that differences and uncertainties in the collection and processing of hydrological information in different countries are a key difficulty in organizing monitoring, both at the international and at the state level.

The paper deals with present hydrological and hydrochemical regime of southern Khibiny rivers affected by apatite-nepheline mining activity. Changes in water quality resulting from mining activities include increase of water turbidity, concentrations of major ions and trace elements. The impact of mining area can be traced over 34 km downstream. We conclude that existing treatment system is not sufficient to mitigate pollutants loads leading to elevated concentrations of toxic substances in dissolved and suspended modes. The process substances concentration reduction is mainly represented by dilution, since the hydrochemical decrease is insignificant. Using trace elements migration phase distribution, the effect of treatment plants on elements distribution downstream was observed.

Abstract On the basis of field experiments the Fe and Mn fluxes for various types of soils were evaluated. It was found that dissolved Fe and Mn fluxes in hydrogen sulphide black silts are significantly lower in the presence of gas bubbles than in their absence.

Abstract The results of studies of exchange processes at the “water – bottom sediments” border for the summer period 2017–18 at the Mozhaisk reservoir are presented. The factors that determine the intensity values of methane and mineral phosphorus fluxes from bottom sediments as well as their spatial non-uniformity, associated with the soils distribution characteristics in the valley-type reservoir, are analysed.

Specific features of the regime of the Borovno-Razliv lake-river system are investigated, as well as the mechanism of the flow of dissolved mineral and organic substances and exchange processes between bottom waters and soil during different seasons within theterritoryofValdainational park. The actual hydroecological state of water objects is considered taking into account specific conditions of nature and water management in the region. The results of investigations made it possible to suggest the optimum terms of further observations on the lakes of the Borovno-Razliv system and other lakes of the national park.

The isotopic features of Lake Trekhtsvetnoe in the White Sea coast area were studied in 2012–2015 in both winter and summer. Lake Trekhtsvetnoe is a water body, separating from the sea, with constant vertical stratification throughout the observation period. Its isotopic, hydrophysical, and biological characteristics have been studied. By the isotopic profile of lake water body, three zones can be identified in the lake: (1) 0–1 m: mixolimnion zone with δ 18 O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ 18 O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ 18 O—from–5.5 to–4.7‰.

Complex study of rivers and lakes of the Valdai national park watershed was carried out at the end of January – early February, 2010. Modern hydroecological condition of water objects with special conditions of nature and water management was estimated. Obtained data has given an opportunity to characterize water regime and runoff of dissolved substances within the protected area.