Water Resources

It is shown that the awareness of the regularities and causes of variations in the Caspian Sea level from the moment of its origin as an isolated lake basin in the Late Miocene (7.2 mln years ago) is of great importance for paleohydrology. Out of the seven principal hydrologic stages of the Caspian Sea history, four stages are considered in this paper: two lake stages (the Late Miocene and Middle Pliocene), the intermediate stage when the Caspian and Zanklinian basins were connected, and the stage of the Manych runoff. An important fact in the Caspian Sea history is emphasized: penetration of the Akchagylian fauna forebears into the Caspian Sea Basin through the Black Sea and the nowadays nonexistent Kuban–Terek Channel (between 5.3 and 3.3 mln years ago). Three phases of penetration of the Mediterranean Zanklinian fauna into the Caspian Basin are recognized. The channel became closed during the Middle Pliocene phase of the Great Caucasian Range elevation (3.3–2.5 mln years ago). This isolation of the Caspian Basin caused the formation of the Great Akchagylian Lake. Its water washed out the New Manych Channel 2.5 mln years ago. From this moment on, the events that occurred in the Caspian Basin and in the Black and Mediterranean seas can be correlated in greater detail, link by link, within the 413-thousand-year period of water abundance.

Materials of half-century observations of zooplankton in the Rybinsk Reservoir were used to establish reversible variations in its structure, abundance, and biomass and irreversible variations in the characteristics (trends). Variations with periods of ∼10 and 20 years have the largest effect on the community dynamics. Regression models are presented describing the dependence of zooplankton biomass averaged over May–October on its values in summer months and on the concentrations of chlorophyll a and phytoplankton and hydrothermal characteristics of the water body. Changes in zooplankton community under the effect of eutrophication and de-eutrophication of reservoir ecosystem are discussed. Keywordsreservoir-zooplankton-composition-structure-abundance-biomass-regularities in dynamics

Changes in the Aral Sea coastline and coastal zone over different time intervals during the period of the sea level drop are studied with the use of space photographs obtained from the orbital station Salyut-4 and satellites of the Resurs-O system. Interannual variations in the above characteristics are analyzed for 1975–1989, 1989–1993, 1993–1996, 1997, 1998, and 1999. Seasonal variations in the water area and coastal landscapes are studied with the help of photographic images of the sea made in different seasons, mainly in 1998.

The characteristics of zooplankton of the Sheksna Reservoir are presented for years with different water abundance and weather conditions. Zooplankton of Lake Beloe (Belozerskii Pool of the Sheksna Reservoir) is shown to retain the characteristics of a limnetic community, which was typical of the lake before the onset of Sheksna runoff regulation, with a predominance of crustacean biomass.

The specific features of cold bottom intrusion in Baikal are considered based on the results of observations of 1993–2009. It is shown that the intrusion-related renewal of bottom water takes place not regularly and not simultaneously in different hollows. Its maximums were recorded in Southern Baikal in 1997 and 2007, in Middle Baikal in 1995, 2006, and 2009, and in Northern Baikal in 1997 and 2009. In these years, the volume of cold bottom layer in some hollows reached 200–470 km3 and its total cooling reached −20 to −60 MJ 109. Cold intrusions were more frequent and had greater effect on the bottom layer in Southern Baikal than in other parts of the lake. The intrusions, especially in the years of their active development, are shown to cause water cooling in both the bottom layer and the major part of the deep-water zone of all hollows. KeywordsBaikal–deep convection–bottom layer–thermal effect of intrusions–space and time features

The results of studies of the Ivankovo, Uglich, Rybinsk, and Gorkii reservoirs are analyzed. The studies involved a wide range of hydrochemical (salt composition, biogenic elements, organic matter, oil products, and heavy metals) and hydrophysical characteristics in the summer low-water period. The concentrations of organic matter and major biogenic elements are shown to decrease downstream along the chain of reservoirs with a respective general decrease in the trophic status. Large built-up areas located downstream of the Rybinsk Hydroelectric Plant are shown to adversely affect the river water quality.

Analysis of sea current velocities showed that the principal flow has a southeastern horizontal direction and downward vertical direction. This flow pattern persisted throughout the observational period. Abrupt temperature drops and water salinity rises are indicative of the near-shore upwelling that was recorded twice during this period. A steady tendency toward a decrease in oxygen concentration and an increase in pH was observed during the observations.

In this article we analyse and compare the data on consequences of the catastrophic 2002 floods in two subcatchments of Otava river basin collected during specialized mapping in 2003. The Otava River is situated in the southwest of the Czech Republic. From its basin we have chosen two different subcatchments: Lower Otava River, surrounded by flat, lowland landscape and Losenice River, swift stream descending from the Sumava Mountains. We also present some basic data on the flood course and its hydrological parameters and meteorological causes.

Results of field studies conducted in the Terek delta in 2002–2004 are presented. Seasonal vertical deformations of the river bed in the lower course of the main branch (the Novyi Terek) are shown to vary within 0.5–1.3 m; intense development of the delta bar takes place. Regeneration of water streams that died away in the 1980s–1990s, and the formation of a new channel network in the lower part of Terek delta are recorded.

Water resources of the Russian Federation in 1930–2000 are assessed. It is shown that, as a result of intensification of general atmospheric circulation, water resources increased since 1981 to 2000 by about 6% as compared with those for 1930–1980.

The effect of potential climate changes on the ecosystem of Lake Ladoga at different levels of anthropogenic load is studied using mathematical models. The Lake Ladoga year-round circulation corresponding to potential climate changes in the lake catchment area is reproduced. The year-round regime of functioning of the lake ecosystem is reproduced using ecosystem models. The potential changes in the lake ecosystem due to changes in the phosphorus load within the limits observed in 1961–1983 are found to be more essential than those due to prognostic changes in climate.

Ranking: This paper ranks 1st: The Effect of Synthetic Surfactants on the Hydrobiological Mechanisms of Water Self-Purification (Article) (Altmetrics, 2015); https://www.researchgate.net/publication/227176754; DOI 10.1023/B:WARE.0000041919.77628.8d; http://link.springer.com/article/10.1023/B%3AWARE.0000041919.77628.8d ; http://5bio5.blogspot.com/2015/02/it-ranks-1st-effect-of-synthetic.htm; The author's experimental studies of the biological effect of surfactants, including the effect surfactants exert on filter feeders, are reviewed. The role of filter feeders in the functioning of freshwater and marine ecosystems is analyzed. New aspects in the assessment of environmental hazard due to the impact of chemical pollutants, including surfactants and detergents, are established.

Published data and the measurements of organic matter content of water performed in the Laboratory of Biophysics, Institute of Laser Physics, SD RAS, in cooperation with the Laboratory of Laser Spectroscopy, Novosibirsk Technical University, with the use of laser fluorescence spectroscopy with fluorescence excitation at a wavelength of 266 nm (the fourth harmonics of a neodymium laser) are analyzed.

Global 90Sr discharge from the soil cover was estimated for a period of 30 years for rivers flowing in the European and Asian parts of the Russian North. The volumes of 90Sr discharged from the watersheds of the Northern Dvina, Pechora, Yenisei, and Lena rivers were found to differ.

The effect exerted by the engineering reconstruction activities in the Pripyat River floodplain and changes in the functional state of the melioration systems in the Chernobyl Abandoned Zone on the transformation of runoff characteristics within the period after Chernobyl accident is considered. Multivariate analysis is applied to study the environmental radiological situation resulting from the changes that have taken place. The distribution and migration of radionuclides within ameliorated watersheds are shown to be controlled by the specific features of the current state of melioration systems, cessation of operation, and damming of canals. These factors has affected the area waterlogging; the surface and subsurface water regime, their nutrition, discharge, and secondary pollution.

Largest river basins in Russia, Lithuania, Ukraine, and Uzbekistan are compared with respect to the admissible levels of the environmental physicochemical factors, the violation of which entails ecological disturbance of hydrobiont communities. The determination analysis of data is used to study the dependence of the degree of adaptation of limnetic ecosystems to external impacts on the sampling site (water column or ground), the latitude, climate, distance from sea, and the density of population in the region under study. Geographical and climatic classifications of regions are proposed based on the variability in the limits of environmental tolerance to abiotic impacts.

Analysis of field and laboratory measurements and theoretical studies was used to establish that the generally adopted logarithmic shape of wind speed profile near the ocean surface does not hold in the presence of waves. It was shown that, under the conditions of developing or developed waves at high wind speed, this profile assumes the form of two logarithmic branches, which join at a large height where wave-induced pulsations of wind speed decay. A model of wind speed profile under these conditions was constructed.

The results of field studies of time variations in the concentration of suspended sediment above a wavy bed under the conditions of irregular waves are considered. A simple procedure is proposed for predicting this concentration based on an advection–diffusion model and field observational data.

Migration of biogenic substances in peats of high and low-level bogs is discussed. Experiments were carried out to determine the quantitative characteristics of the absorbing capacity of peat. A high ability of peat to absorb and hold biogenic substances was revealed. This ability depends on the degree of biogenic substance decomposition and on the amount of finely divided particles, and it is not similar in different types of biogenic substances.

Based on the analysis of data of many-year actinometric observations, a considerable temporal (interannual, seasonal, synoptic, and diurnal) and spatial variability of the albedo of the snow-and-ice cover of a shallow lake is shown. The ranges of variations in the albedo of snow and ice for a wide spectrum of the state of surface and weather conditions are presented. The variability of the thickness and structure of snow-and-ice cover is analyzed for different periods in winter. The results of field experiments aimed to determine the degree of absorption of solar radiation by snow and ice are presented. The effective coefficients of absorption of solar radiation by snow and ice are determined. The comparison of the observed and calculated values of the under-ice radiation has shown that the determined coefficients adequately describe the absorption of solar radiation by snow-and-ice cover.

The paper presents the results of analysis of present-day scientific data on the dynamics of global hydroclimatic processes (with the establishment of long-term variations in the global water exchange processes) and the features of water abundance in territories under the effect of various natural and anthropogenic factors. Possible transformations of the hydrogeological situation under global climate changes are considered. The basic principles of the concept regarding the assessment of the effect of global hydroclimatic changes on the population health are presented. Medical-environmental data on the consequences of water-triggered environmental crises, taken as analogous natural models, are analyzed. The processes and regularities in the development of human pathology under the conditions of higher and lower water abundance in a territory are identified. The succession, time stages, and phases of the development of infection, parasitic, noninfectious pathologies are determined. Cause-and-effect relationships were established between the observed pathology and the effect of a complex of changing natural, anthropogenic, and social-environmental factors. Methodological approaches to the assessment of medical-environmental consequences of distinct changes in the water abundance in the territories are described. The possible use of subsurface water sources as a reserve of domestic water supply under emergencies are considered.

The distribution law of averaged coefficients of aeration is established for the aeration zone in accelerated turbulent flows in prismatic channels, and a technique is proposed for the evaluation of the length of this zone. Both the results are in agreement with the data of special laboratory studies. The estimation of the length of the aeration zone is based on relationships derived by the author and verified for flow-controlling parameters varying within wide limits. The law of increasing air content was also confirmed by field measurement data.

Mathematical models describing the processes taking place at gas pipeline breaking are presented. The characteristics of the non-steady-state gas flow from the underwater pipeline into water are calculated using hyperbolic equations of gas dynamics. It is shown that the model of gas-liquid jet propagation in water, based on experimental data, allow the evaluation of the rate, mass, and the time of discharge, the size of pollution source, the density of gas–water mixture, and the pollutant concentrations on water surface at different scenarios of accidents. An example of calculation of these characteristics is given.

A numerical model describing the interaction between flows in channel and floodplain is developed based on two-dimensional flat equations of turbulent fluid hydrodynamics. A high-resolution finite-difference grid was used to enable the authors to provide a direct description of large vortices in the turbulent field, which are generated on the boundary line. Energy transformations in the channel-floodplain system were analyzed and the possibility to use phenomena of counter-gradient transport, known as the “negative viscosity,” was demonstrated. Quantitative estimates were obtained for interaction effects in flows with simple geometry.

Seasonal variations in water temperature in Selenga Shallow Waters is studied. The contributions of the regimes of waves, river runoff, thermal fronts, and thermobars to the formation of physical structures are assessed.