Vol 46, No 3 (2019)

The balance structure of the pumpage sourses of riverside water-intakes, developing a subsoil aquifer or intermediate water that hydraulically interacts with it, can show the effect of the processes of water balance adjustment in the unsaturated zone to the accompanying subsoil water level drawdown. In this case, because of the shallow depth to subsoil water, its level drop due to water withdrawal causes a decrease in evapotranspiration and an increase in groundwater infiltration recharge. These processes have their effect on the balance structure of usable water resources as components of natural and involved resources and reduce the impact of groundwater pumping on river flow. Analysis of the operational data of the Sudogda water-intake in Vladimir oblast and geohydrological modeling were used to evaluate variations of the groundwater evaportanspiration losses and infiltration recharge and their role in the water balance structure of reserves of a field and in the impact of groundwater withdrawal on river flow.

Under the background analysis of water issues, water environment random evaluation model based on Bayesian theory is put forward to universally describe and physically analyze the uncertainty information. Guided by the viewpoint of sustainable development, this study applies water conservancy science, intelligence science and information science to discuss about risk indexes from three aspects of water quantity, water quality, and water ecology with the evolution mechanism of water environment. The evaluation index system is selected by qualitative analysis and quantitative calculation, and index weight is determined by the improved TOPSISI method. The Bayesian theory is employed to set up the random evaluation model. The process is to obtain posterior distribution by prior distribution with sample information. Then, the evaluation levels of water environment are given by the principle of probability maximization with advancing the control policy. Taihu Basin, China is taken as an example. It shows that the proposed model is rigorous with theory, flexible with method, and reasonable with results, providing a new way for studying water resources shortage, water pollution prevention, and water ecology protection, which can be widely applied to water environment management.

Turbulent flow is a flow regime which is described by the anarchic property changes. This includes the rapid variation of pressure, high momentum convection and flow velocity in time and space. A turbulent phenomenon in a braided river is much more complex as compared to the straight and meandering rivers. Turbulent flow characteristics around the braid bar are not thoroughly studied till now. In the current paper, the quadrant method is used to analyze the turbulence characteristics of flow around the island in a braided river model using 2-D burstingevents technique. Three velocity fluctuation components (u′, v′, w′), were measured with Acoustic Doppler Velocimetry. Although many advances have been made within recent years in interpreting the mechanics of flow, transport of sediment and sedimentary architecture of braided rivers, many key issues remains to be addressed, in particular, the underlying processes of braid bar initiation. An attempt has been made herein to relate the depositional characteristics around the island in the braided river model to the sweep and ejection events. The concept of the hole is used in order to isolate the extreme events that contribute to the turbulent burst. The angle of sweep and ejection events are calculated at points around the island. The angle of events at these points depict the pattern similar to scouring/ deposition at points around the island in the braided river model.

Roughness coefficient, also called Manning’s coefficient, is one of the most important hydraulic parameters in the rivers. This coefficient, in addition to the flow conditions, depends on streambed characteristics such as type and density of vegetation. In this study, a physical model in a flume with 7 m length, 0.25 m width and 0.25 m height was conducted to evaluate the streambed roughness coefficient and consequently the discharge passing from waterways. Flume bed was filled using uniform sediment with median grain diameter of 1.9 mm, variation coefficient of 1.4 mm and a thickness of 0.4 m. Roughness coefficient variation in the slopes of 0.2, 0.4 ,and 0.6%, discharges of 4, 6, and 8 L/s and vegetation cover densities as 0, 12, 25, and 50% were investigated. To simulate the covering of streambed, vegetation scrub was used in the experiments. The results showed that by increasing the density of vegetation, roughness coefficient increases while with increasing flow velocity, slope and Froude number decreases. By analyzing the data from this study, streambed roughness coefficient was obtained in terms of different variables as applicable relationships for different conditions of flow and streambed. The results of this study with quantifying the effects of various parameters on the roughness coefficient can be used by water engineers.

Data of long-term measurements of under-ice solar radiation, water temperature, and chlorophyll a are analyzed in four phytoplankton groups (green, diatoms, blue-green, and cryptophyte algae) in a small mesotrophic Vendyurskoe Lake (Karelia) in the period of spring under-ice convection. It is shown that, after thawing away of snow cover from lake surface, under-ice illumination increases, water temperature rises, the depth of convectively mixed layer (CML) increases, and microalga photosynthesis intensifies. In the daytime, chlorophyll a extremums appear in the CML, and, unlike the homogeneous characteristics (water electric conductivity, mineralization, etc.), the cells of different phytoplankton species can be used as tracers in studying convective mixing. A prognostic equation is obtained, reflecting an inverse dependence of the coefficients of variation of chlorophyll a concentration in CML on solar radiation fluxes, penetrating under ice bottom surface. A direct relationship was shown to exist between the increase in chlorophyll concentration in CML and its thickness.

The size structure of zooplankton in Kolsay Lakes was characterized with the use of the values of Clarke W-statistic, ∆-Shannon–Weaver, and the average individual mass of the organism. The species composition remaining relatively stable, the year-to-year dynamics of the size and abundance characteristics of zooplankton suggested more rapid eutrophication processes in three out of four Kolsay Lakes. The year-to-year changes in the structure of zooplankton communities were largely determined by the immigration of an allochthonous fish species, a drop in water level, and an increase in the biogenic load caused by the recreation use of the lakes. The effect of very low concentrations of heavy metals on the zooplankton size characteristics can be due to the oligotrophic status of the Kolsay Lakes.

The concentration of the technogenic radionuclide ¹³⁷Cs was studied in different groups of salt lakes of Crimean Peninsula. It was established that one of the major sources of ¹³⁷Cs input in them is the North Crimean Canal, which, up to 2014, had been delivering the Dnieper water with a high concentration of radionuclides of Chernobyl origin. Another source of ¹³⁷Cs inflow is Black Sea water through its drainage and direct interaction with the coastal salt lakes of Crimea, in which a positive correlation was observed between ¹³⁷Cs concentration and water salinity.

Data on the concentrations of Cd, Cu, Pb, and Zn in bottom sediments of Amur Bay are given. The pollution of bottom sediments is especially heavy near the central part of Vladivostok City, where the concentrations of all metals, except cadmium, are in excess of their threshold level above which adverse biological effects are possible. Bioassay (2003–2014) has shown the toxicity of water for marine crustaceans in local areas within this most heavily polluted part of the bay. However, the survival rate of mysids in the surface water from the entire inner area was reliably less than that in the external part of the bay only in August and September 2003 and July 2007. In the following years, the ecotoxicological state of bay water improved, possibly because of a decrease in pollution.

With the acceleration of industrialization and urbanization, the water crisis is becoming more severe and may threaten the future of sustainable development. Assessing grey water footprint (GWF) is a useful step in the prevention and control of water pollution. Conventional studies have only considered agricultural pollutants in their calculations of GWF, ignoring the roles of industrial and household wastewater. Therefore, this study calculates GWFs for the agricultural, industrial, and household sectors in 31 provinces in China from 1998 to 2012. It further analyzes spatial and temporal variations in China’s GWF. The results show that total GWF (TGWF) was relatively high from 1998 to 2002, then increased steadily and peaked in 2006, and dramatically decreased after 2006. Overall, TGWF slightly decreased over the study period. 31 Provinces were divided into five grades of TGWF: very high, high, medium, low, and very low. The provinces with high or very high TGWF, such as Hebei, Shandong, Henan, Jiangsu, Hubei, Hunan, Sichuan, Guangdong, and Guangxi, were primarily located in southeastern and southwestern China. Therefore, efforts to reduce GWF should focus on these regions. Our comparative study also provides a means of understanding how key contributors to GWF vary across the five regions. It offers a basis for the short-term and long-term development policies aimed at decreasing GWF in specific locations.

The interaction between hydrological cycle components in the ocean–atmosphere–land system was considered. Calculations were made with the use of various reanalysis archives, and regularities in the interannual variability of evaporation and precipitation in the North Atlantic and their effect on the zonal transport of water vapor onto the European continent were considered. Statistical models of the annual average total moisture flow at the meridional section 5° E as a function of evaporation in the North Atlantic were constructed. The contribution of the zonal transport of water vapor at the meridian 5° E to the variance of the total precipitation over cold and warm seasons in the Volga basin was determined. Models with a small number of parameters were constructed for forecasting the annual runoff of the Volga as a function of precipitation by methods of multiple regression and decision trees.

The article continues the discussion of the developed new computer technology for the analysis of problems and decision support in the supply of water resources to the users of the water management system of the Lower Volga and the entire Volga–Kama chain of reservoirs. The second part considers the problems of tactical planning, which determine the release into the lower pool of the Volgograd Hydropower System (special release), and proposes a new algorithm of dispatching control, which is now in use for the support of the process of determining the special release, based on the forecasted inflow during spring flood (April–June), and implements the objectives chosen at the stage of strategic planning.