Volume 45, Nº 5 (2018)

Water resources of lakes with natural and regulated hydrological regime are evaluated, and estimates are given to the water resources of artificial water bodies in three federal districts in the Asian part of RF (Ural, Siberian, and Far-Eastern) and the constituent entities of the Federation they contain. The estimates were made by a new procedure, incorporating up-to-date satellite data and functions of Google Earth project. In the Asian part of RF, ~3140000 natural water bodies were analyzed, including ~1170000 lakes >1 ha in area and ~6000 artificial water bodies. Lake water resources in the Asian part of RF amount to 24537 km³, of which ~96% are contained in Lake Baikal. Other 638 km³ are contained in artificial water bodies.

The article presents the first study of the long-term dynamics of ice phenomena in lakes of different landscape–climate zones in the Southern Urals. The overwhelming majority of lakes, whatever their typology and geographic occurrence, show a decrease in the duration of the period of ice phenomena at a longer open-water period because of the later freeze-up. The governing factor in the long-term dynamics of ice phenomena is the mean annual air temperature. The largest is the effect of the average air temperature in the freeze-up period (October–March). The morphometric, hydrological, and hydrochemical characteristics have no direct effect on the differences in the long-term dynamics of ice phenomena in individual lakes. These differences are determined by the landscape–climate zones. The difference between water bodies in urbanized landscapes and other water bodies is much greater than that between the lakes in natural landscape–climate zones.

The method has been developed to evaluate water and heat balance components for vegetation covered area of regional scale based on the refined physical-mathematical model of vertical water and heat exchange between land surface and atmosphere (Land Surface Model, LSM) for vegetation season adapted to satellite information on land surface and meteorological conditions. The LSM is accommodated for utilizing satellite-derived estimates of vegetation and meteorological characteristics as model parameters and input variables. Estimates of these characteristics presented as distributions of their values over the study area have been obtained from AVHRR/NOAA, MODIS/EOS Terra and Aqua, SEVIRI/Meteosat-9, -10 data. To build such estimates methods and technologies have been developed and refined using results of thematic processing measurement data from these sensors. Among them the original Multi Threshold Method (MTM) has been developed and tested to calculate daily precipitation sums using rainfall intensity estimates retrieved from AVHRR and SEVIRI data with subsequent replacement of ground-measured rainfall amounts by these daily rainfalls. All technologies have been adapted to the study area with square of 227300 km² being the part of the Central Black Earth Region of European Russia. Developed earlier procedures of utilizing satellitederived estimates of vegetation and meteorological characteristics (including precipitation) in the model have been refined and verified. Final result of modeling is the fields of soil water content, evapotranspiration and other water and heat balance components of the region under study for years 2012–2014 vegetation seasons.

Results of field observations of current dynamics in the frontal zone of the western Middle Caspian are given. The cyclonic circulation over the western slope in winter is shown to be a unidirectional intense current with velocities up to 100 cm/s. In summer, the current slows down and separates into branches—it turns southwestward and westward at the slope depth down to 150 m, southward and southeastward at the depth of ~100–350 m, and eastward at larger depths. In summer, shelf currents interact with the flow of Middle Caspian cyclonic circulation, resulting in that anticyclonic vortices reach the shelf.

The Marine and Atmospheric Research System (MARS) for the Caspian Sea meteorological characteristics is presented, which is implemented in Zubov State Oceanographic Institute. It includes computation of the atmospheric forcing with the Weather Research and Forecasting model, as well as computation of currents, sea level, temperature, salinity and sea ice with the Institute of Numerical Mathematics Ocean Model and the computation of wind wave parameters using the Russian wind-wave model. The results are presented on verification of the hydrometeocharacteristics simulated with the MARS for the Caspian Sea. As well, the retrospective simulation of the thermohydrodynamic characteristics in this basin is performed with MARS for the ice-free period 2003–2013. The important features of the Caspian Sea circulation are shown.

Increasing salinity in Urmia Lake, located in the north-west of Iran, has turned into a critical issue, particularly because the lake is the habitat of a unique multi-cellular organism called Artemia Urmiana. During the past decades, several anthropogenic changes have taken place in the lake, which have resulted in increased salinity. This study introduces a reduced-order framework based on MIKE3 simulation model and proper orthogonal decomposition (POD) to simulate salinity patterns in Urmia Lake. Spatio-temporal variations of salinity in the lake firstly were simulated by MIKE3, and close matches were observed between salinity estimates from MIKE3 and those of the field data. Thereafter, 365 daily snapshots were taken from MIKE3 simulations, and subsequently 365 POD basis modes were computed. Due to high percentage of conserved energy of the lake system (salinity of lake) within the first ten POD basis modes, these modes were considered to develop a reduced-order salinity model (ROSM). Finally, results from MIKE3 were compared with the ROSM. It was shown that the first ten modes (among 365 modes) obtained by the POD conserved approximately more than 99.8% of the energy of the system. Moreover, using the first ten modes resulted in an error in magnitude of less than 0.01. Therefore, the ROSM could successfully capture the variations of salinity in the lake via its first ten modes.

Iron migration forms and variations of its concentrations in water and bottom sediments of the Vygozero Reservoir were studied in period from 1993 to 2014. The decrease in wastewater volume discharged from the pulp and paper mill in the early 1990s caused stabilization of water oxidation regime and accumulation of iron in bottom sediments, from which it returns into the water mass when the environmental conditions change in the seasonal oxygen cycle.

For the first time in the Middle Ob Basin, new data of importance for evaluating the quality of swamp and river water were obtained, characterizing the microcomponent composition of extractive organic compounds. More than 150 compounds of natural genesis were identified. The water of oligotrophic and mesotrophic bogs shows widest diversity and maximal, almost equal masses of extractable organic substances, averaging 13357 ng/L. In the water of eutrophic bogs and taiga rivers, this characteristic is five times lower; and that in lakes is lower by more than an order of magnitude. The amount of extractive trace components is closely correlated with the concentration of water-soluble carbon of humic nature. It was established that the natural water of taiga zone identical in terms of the fulvate type differs in the composition of organic trace components and can be grouped into four clusters: (a) water of oligotrophic bogs, (b) water of mesotrophic bogs, (c) river water, and (d) water of eutrophic bogs and bog lakes.

The results of studies of variations of δ¹⁸O values in river water in Crimea Peninsula in January–February 2015–2017 are given. The variation range of δ¹⁸О in river water over the three years of studies never exceeded 3‰. A tendency toward an increase in δ¹⁸О in the water of the Salgir, Kacha, Al’ma, Bel’bek, Biyuk-Karasu from their sources to mouths was identified and explained by a decrease in evaporation in the mouth areas of the rivers relative to their sources and upper reaches, and the inflow of isotopically light precipitation (rain and snow) into the rivers in their upper reaches. The values of δ¹⁸О in waters of the rivers with regulated stream were found to increase under the effect of the Simferopol Reservoir on the Salgir River and the Izobil’nenskoe Reservoir on the Ulu-Zen’ River. The values of δ¹⁸О in the upper reaches of the large rivers of Kacha and Bel’bek (the northwestern slope of the Crimean Mountains) vary from −8.7 to −9.7‰, except for the rivers of Al’ma (−7.7‰) and Kokozka (−10.2‰) because of the different shares of groundwater in the recharge of these rivers.

Historical changes in lake sedimentation for the last 150 years and the lifetime of lakes of Ishikari Wetland are reconstructed in this study. The floodplain wetlands surrounding the lakes have gradually converted to farmlands since the 1890s. ²¹⁰Pb activity in lake profiles was found to have a non-exponential decrease with depth due to increased and variable sediment flux from agricultural activities. ²¹⁰Pb dates of these lakes were calculated in this study using constant rate of supply model, which was in good agreement with the date based on ¹³⁷Cs method. The average total sediment mass in the lakes under natural conditions were 54–112 ton/year until 1890s. It was increased to 111–1055 ton/year after 1890s due to conversion of floodplain to agricultural lands. Especially, lakes after the 1940s had the highest sediment accumulations due to sediment influx resulting from intensification of agriculture via increasing farm size and destroying swamp buffers surrounding the lakes. The time forecasted for filling lakes based on post-1940s sediment accumulation mass was about 15 to 23 years. Restoring swamp buffers surrounding the lakes and converting to low intensity agricultural activities are needed to restrict lake shallowing.

Objective analysis of water resources development in the territory of Vologda oblast in period from 2005 to 2014 is given. It was found that water withdrawal from water sources decreased by 22.4%, wastewater discharge into water bodies decreased by 22.6%, and the total volume of recycling and successive water use increased by 2.0%. The dynamics of the distribution of water resources between economic sectors is given. Unreasonable water losses were identified in water use systems and their extent was assessed. The main directions in water economy in the production and domestic sectors are determined. Steps for improving the efficiency of water resources development in the region are proposed.