卷 45, 编号 2 (2018)

ECOMAG software complex was adapted to simulate river runoff in the Amur basin using data from global databases (relief, soils, landscapes). The results of model calibration and verification were used to give a statistical estimate of the efficiency of river runoff calculation over a long period based on standard data of meteorological and water management monitoring. The results of calculations using the developed runoff formation model were used in the space and time analysis of the formation conditions of 2013 flood in the Amur basin.

Interaction between water flow and ridge bedforms has been studied. The results of experimental studies of velocity distribution over ridge bedforms in a hydraulic laboratory flume are given. The distribution of pressure along the contour of a rigid model ridge, determined in an aerodynamic canal, is also given.

The decrease in Aral Sea area, which started in the 1960s, caused considerable changes in the hydrological, chemical, and biological structure of sea water. Regular observations of Aral water chemistry ceased in the early 1990s. There were no observations of the concentrations of biogenic element compounds in water (the so-called “first-day analyses”). During expeditions of the Institute of Oceanology, RAS, in September 2012 and October 2013, integrated hydrochemical observations were carried out, including measuring the concentrations of biogenic element compounds, dissolved oxygen, hydrogen sulfide, and carbonate equilibrium components. An objective of this study was to develop methods of hydrochemical studies under high water salinity (mineralization). In addition to the standard hydrochemical complex, water samples were taken to determine total water mineralization and the concentration of dissolved and suspended metal forms. The results of these studies are given.

Seasonal dynamics of the mineralization, ionic composition, and the concentrations of specific pollutants in subsoil water are studied in populated localities in the southern Rostov oblast. Four major water types are identified: hydrocarbonate–sulfate (sulfate–hydrocarbonate), sulfate, chloride–sulfate (sulfate–chloride), and mixed type of subsoil water. The quality of subsoil water was found to fail to meet the sanitarytoxicological standards in terms of many characteristics. The values of MAC are exceeded for calcium, magnesium, sodium, chloride and sulfate ions, oil products, cadmium, total iron, silicon, and nitrate and ammonium nitrogen. Relationships were found to exist between the concentrations in water of cadmium, potassium, and phosphorus ions; oil products; pH values; water mineralization and total hardness; and seasonal variations of subsoil water levels. The identified relationships were substantiated.

Sevastopol Bay is used as an example for the development of criteria for rating anthropogenic impact by elimination fluxes from the water area of post-Chernobyl (⁹⁰Sr, ¹³⁷Cs, ^239,240Pu) and natural (²¹⁰Pо) radionuclides, as well as mercury and organochlorine compounds. The differentiation of the bay water area into zones with different biogeochemical conditions and the balance approach to interpreting field observation data were used to assess the conditioning capacity of Sevastopol Bay ecosystem for conservative radioactive and chemical substances by elimination fluxes of pollutants into aqueous depot, which is the open part of the Black Sea and into the geological depot, i.e., its bottom sediment stratum.

Drinking water supply in Lithuania is entirely based on groundwater. Wellfields of Vilnius develop intermorainic ca. 50 m deep (in average) aquifer which is locally contaminated by chlorinated hydrocarbons— volatile organic compounds (VOCs). Groundwater abstraction activates VOCs migration from an abandoned factory into the pumping wells of one wellfield named “Vingis.” However monitoring data testify that only traces of VOCs were detected on the territory of this factory. Subsequent studies revealed the “secret”: dense VOCs have migrated from the territory of the polluter and have accumulated in lowermost places of pumped aquifer inside the wellfield. An attempt to ensure low concentration of VOCs in pumped water manipulating by pumping rates of more or less contaminated abstraction wells was not effective. Finally, an acceptable concentration of VOCs in supplied drinking water was ensured by permanent pumping out of the most polluted groundwater from some abstraction wells of the wellfield and diverting this water to the Neris River.

Maintaining the quality of surface water resources as one of the most vital water supplies has always been at the center of global concerns. A set of manifest and latent factors have yet been identified by researchers worldwide that are subject to affect the quality of surface water. Among which, the effect of land use change, due to a spatial and temporal complexity, is often not easily verifiable. The present study attempts to offer an index-based model to quantify vulnerability of surface water resources in a semi arid basin in central Iran against land use changes. For this, water quality data including Na, K, Mg, Ca, Sodium Adsorption Ratio (SAR), total anions (Sum. A), SO₄, Cl, HCO₃, EC, TDS, and pH were collected from hydrometric stations over a period of 26 years (1987‒2013). In order to detect land use changes, the land use maps of the years 1987, 1998, 2002, 2009, and 2013 were prepared from TM satellite images using supervised classification method. At next step, changing patterns of different land uses were traced by Shanon’s Diversity Index (SHDI) as a metric of patch diversity indicating diversity and heterogeneity of a landscape over time. Relationship between the SHDI values and water quality indicators revealed the impact of land use changes on quality of surface water resources. Statistical analysis confirmed a significant relationship between nine water quality factors and water discharge in the basin during the study period. From 1998 to 2009, the greatest changes were visible in the total anions, Ca, SO₄, and HCO₃. These parameters along with salinity were increasing in almost all sub-basins. According to the results, conversion of poor rangelands to rain fed agriculture fields is the most apparent land use change occurred in the study area over the study period. In 1987, SHDI as an indicator of the diversity and changes in the basin, showed a significant relationship with good rangelands (R² =–0.835). This indicates that fragmentation of the entire watershed area was initiated in 1987, which reached its peak in 2013. Generally speaking, urbanization, poor rangeland, and irrigated agriculture were recognized as three influential land uses adversely affect the water quality in the study area.

The extremely high rate of evaporation from water surfaces in arid and semi-arid areas greatly reduces optimal utilization of water reservoirs. In Algeria, which is at 80% an arid country, water resources are scarce and renewable due to low annual precipitation. Considering the importance of optimal utilization of renewable water resources, about 70 dams with capacity of 7.4 billion m³ were constructed. One of the biggest problems of water in dams in Algeria is the huge amount of water loss through evaporation due to high evaporation rate. Therefore, applying techniques to reduce evaporation are greatly needed. One of the most recommended techniques for reducing evaporation is the application of a thin chemical film on the surface of the water. The present study aims to investigate the effect of this technique under arid conditions. Experiment was conducted for 20 weeks in Touggourt with three Colorado-type evaporation pans. Fatty alcohol with various doses were used in different pans. First pan was filled with water without adding fatty alcohol while in second pan, fatty alcohols was added with recommended concentration (0.3 kg/10⁴ m²/day) and similarly in third pan fatty alcohol was added with concentration (0.5 kg/10⁴ m²/day). The preliminary results of the study indicated that evaporation rate from surface water was reduced overall up to 16 and 22% in the second pan and the third one, respectively as compared to the non covered pan.

The key water-management and environmental problems of the Lower Volga are considered. The items discussed include the characteristics of intake and utilization of water resources and wastewater discharges in Lower Volga Region from 1990 to 2013. The current state of the key participants of water management complex is analyzed. The quality of Lower Volga water and ecosystems is shown, and the problems of maintaining the biodiversity are discussed. The key regional programs pertaining to the rational use and protection of water resources, as well as the development of water-management complex are considered.