Water-Management and Environmental Problems of the Lower Volga and Ways to Their Solution

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.     

A Mathematical Model of Water Supply System Management

The mathematical model considered describes the regimes of a water-management system that ensure the strict implementation of the schedule of water resources consumption. The model is described by a nonlinear programming problem for the distribution of flows on a network (a tree) with a source, simulating a source of water resources with an unlimited capacity, located in the root of which (an analogue of the water intake headwork). The main problem is approximated by four problems solved successively.     

Comparative analysis of anthropogenic impact on water resources in Russia,Belarus, and Ukraine in the post-soviet period

Anthropogenic impacts on water resources in Russia, Ukraine, and Belarus after the collapse of the Soviet Union are considered. Estimates of water consumption and its dynamics since 1990 are given. Current changes in the state of water resources are characterized. Differences in the efficiency of water consumption in the countries under consideration are demonstrated.     

The R-approximation method and its application to the interpretation of detailed gravity and magnetic data

The application of the R-approximation method based on the use of the Radon integral transform within the framework of the method of linear integral representations to the interpretation of detailed gravity and magnetic data is considered in this paper. The results are presented for some research areas located in Russia and in the Crimea (Ukraine). The method determines the distribution of anomalous field elements, construction of the analytical continuation of fields, and their linear transformations with a sufficiently high degree of accuracy.     

Focal Depths of Earthquakes in the Crimea–Black Sea Region

The problem of determining focal depths of earthquakes in the Crimea–Black Sea region is considered. Based on the results of interannual studies, it is found that the focal depths of Crimean earthquakes are mainly crustal, with maximum values of up to 60 km. Some recent publications, however, have described deep-focus earthquakes with depths of up to 300 km which were “revealed” in the Crimean region. In this respect, there arose the need to study such a large difference in estimated focal depths. Convincing examples show that the sensational “revelation” of deep earthquakes in Crimea was caused by incorrect processing of the experimental data, in particular, due to (1) a sharp distortion in the recorded arrival times of body waves, (2) exclusion of data from stations nearest to a source, (3) unreasonable arbitrary selection of data from seismic stations, and (4) dropping of data from the worldwide seismological network, including those on deep seismic phases. Thus, the conclusions about the presence of deep mantle earthquakes in Crimea are erroneous. We have redetermined the parameters of hypocenters and verified that the focal depths of earthquakes in the Crimea–Black Sea region are no more than 60 km. Based on these data, we analyze the features of the spatial distribution of focal depths to show that earthquake sources are grouped along conduits that dip southeastward, from the continental part of Crimea toward the Black Sea Basin, in the case of grouping of sources in the Alushta–Yalta and Sevastopol areas. The seismic focal layer of the Kerch–Anapa area dips northeastward, from the Black Sea beneath the North Caucasus.     

Groundwater Resources and Their Role in Water Supply to Crimea

The processes of formation and distribution of the resources of fresh groundwater and surface water in the territory of Crimea Peninsula are considered. Water availability in the natural–historic and administrative regions of the republic is characterized. The proportions between different categories of groundwater resources are shown with their role in water supply to Crimea taken into account. The presentday development of groundwater resources is analyzed and the possible increase in water consumption meeting geoecological requirements is substantiated.     

The Scientific Basis of Water Safety of Crimea: Problems and Solutions

Water Resources - The present-day knowledge of Crimean water resources is analyzed; the data on surface water and, the more so, deposits of groundwater, as well as the interaction between them are...     

Archeoseismological study in Salachik,the ancient capital of Crimean Khans

Archeological, archeoseismological, and seismotectonic studies were carried out in Salachik, the ancient capital of the Crimean Khans, on the outskirts of the modern city of Bakhchysarai, Crimea. The following damage and deformations of medieval buildings were observed: tilted building walls, shifted elements of building structures, rotation of fragments of walls and building blocks around the vertical axis, considerable deformations of arch structures, and fissures running through several rows of building blocks. These deformations are of a seismogenic nature. Traces of at least two strong ancient earthquakes were revealed in the medieval monuments of Salachik. Based on analysis of kinematic indicators, it is found that the maximum seismic intensity (VIII ≤ I ₀ ≤ IX points) was due to an earthquake occurred in the west. Based on historical seismologic data, one of the two earthquakes is dated by April 30, 1698. Also, structural damage to buildings in Salachik was caused by Crimean earthquakes in 1927. The findings can be used for a comprehensive assessment of seismic hazards on the Crimean Peninsula.     

Legal Aspects of Natural Resources Management in the Basin of the Sea of Azov

Legal aspects of natural resources management in the basin of the Sea of Azov are investigated. The available legal documents and agreements are carefully analyzed. Measures to be taken both to eliminate the uncertainty of the Sea of Azov legal status and to promote cooperation in the natural conservation zone between Russia and Ukraine at the international level are suggested. The experience of Mediterranean countries succeeding in marine environment protection is analyzed.     

Rational Water Use in the Republic of Crimea: Significance,Limitations, and Approaches to Achieve

Water Resources - The aggravating deficiency of water resources in the Republic of Crimea emphasizes the necessity of their rational use. As this should be based on the rational water policy, this...     

On the Problem of Deep Earthquakes in Crimea–Black Sea Region

It is a common opinion that only crustal earthquakes can occur in the Crimea–Black Sea region. Since the existence of deep earthquakes in the Crimea–Black Sea region is extremely important for the construction of a geodynamic model for this region, an attempt is made to verify the validity of this widespread view. To do this, the coordinates of all earthquakes recorded by the stations of the Crimean seismological network are reinterpreted with an algorithm developed by one of the authors. The data published in the seismological catalogs and bulletins of the Crimea–Black Sea region for 1970–2012 are used for the analysis. To refine the coordinates of hypocenters of earthquakes in the Crimea–Black Sea region, in addition to the data from stations of the Crimean seismological network, information from seismic stations located around the Black Sea coast are used. In total, the data from 61 seismic stations were used to determine the hypocenter coordinates. The used earthquake catalogs for 1970–2012 contain information on ~2140 events with magnitudes from–1.5 to 5.5. The bulletins provide information on the arrival times of P- and S-waves at seismic stations for 1988 events recorded by three or more stations. The principal innovation of this study is the use of the original author’s hypocenter determination algorithm, which minimizes the functional of distances between the points (X, Y, H) and (x, y, h) corresponding to the theoretical and observed seismic wave travel times from the earthquake source to the recording stations. The determination of the coordinates of earthquake hypocenters is much more stable in this case than the usual minimization of the residual functional for the arrival time of an earthquake wave at a station (the difference between the theoretical and observed values). Since determination of the hypocenter coordinates can be influenced by the chosen velocity column beneath each station, special attention is focused on collecting information on velocity profiles. To evaluate the influence of the upper mantle on the results of calculating the velocity model, two different low-velocity and high-velocity models are used; the results are compared with each other. Both velocity models are set to a depth of 640 km, which is fundamentally important in determining hypocenters for deep earthquakes. Studies of the Crimea–Black Sea region have revealed more than 70 earthquakes with a source depth of more than 60 km. The adequacy of the obtained depth values is confirmed by the results of comparing the initial experimental data from the bulletins with the theoretical travel-time curves for earthquake sources with depths of 50 and 200 km. The sources of deep earthquakes found in the Crimea–Black Sea region significantly change our understanding of the structure and geotectonics of this region.     

Analysis of Historical Sources on Earthquakes in Crimea

The paper considers the results of an archeoseismological approach to studying the seismic history of Crimea based on recent publications, devoted to reconstructing strong seismic events in the 15th–18th centuries. The reliability of the references involved is analyzed. Reconstruction of the timeline of earthquakes in Crimea is related to two problems: determination of doubtless evidence of a strong earthquake and dating of such an event. The first problem can be solved mostly by careful field studies using the developed technique and with representative historical, literary, and folkloric material, whereas dating of events encounters considerable difficulties. The main difficulties and limitations of this generally progressive research field are shown, which are related to both objective and subjective factors. Objective factors include, in particular, large uncertainty in establishing the chronology of seismic events using not only folkloric, but also historical data. The efficient cooperation of historians and seismologists is complicated by many unresolved issues in the reconstruction of historic events in Crimea, which deprives seismologists of a reliable basis and forces historians to rely on seismological conclusions that are not always valid. Subjective factors are related to lack of scrutiny when using sources and hasty conclusions. In addition, data on geological and man-made destruction in historical sources are used insufficiently. Despite doubts on the reliability of chronologically dating earthquakes, successful application of the archeoseismological method in Crimea is confirmed by solid evidence of strong seismicity. Obviously, to solve the dating reliability problem, further research and more complete reconstruction of Crimea’s history are needed.     

Lake water resources of the European part of the Russian Federation

The article gives the results of estimating lake water resources for federal districts in European Russia and constituent entities of the Federation, carried out in the Institute of Limnology, RAS, with the use of up-to-date satellite images and the program Google Earth. European Russia contains ~610000 natural water bodies >0.1 ha in area, including ~200000 lakes >1 ha in area, and 90000 water bodies of artificial origin. Lake water resources of European Russia amount to 1370 km³ of water, of which 99% are in Northwestern Federal District. Artificial water bodies contain ~250 km³ of water resources.     

Analysis of the Filling of Naturally Flowing Reservoirs for Substantiating Ways to Solve the Problems of Water Supply Security in the Republic of Crimea and City of Sevastopol

Water Resources - The filling of naturally flowing reservoirs in the Republic of Crimea and city of Sevastopol has been analyzed. A set of measures to solve the problems of water supply security is...     

The Upper Valanginian (Early Cretaceous) positive carbon-isotope event recorded in terrestrial plants

Our understanding of the ancient ocean-atmosphere system has focused on oceanic proxies. However, the study of terrestrial proxies is equally necessary to constrain our understanding of ancient climates and linkages between the terrestrial and oceanic carbon reservoirs. We have analyzed carbon-isotope ratios from fossil plant material through the Valanginian and Lower Hauterivian from a shallow-marine, ammonite-constrained succession in the Crimean Peninsula of the southern Ukraine in order to determine if the Upper Valanginian positive carbon-isotope excursion is expressed in the atmosphere. δ¹³C_plant values fluctuate around − 23‰ to − 22‰ for the Valanginian-Hauterivian, except during the Upper Valanginian where δ¹³C_plant values record a positive excursion to ∼− 18‰. Based upon ammonite biostratigraphy from Crimea, and in conjunction with a composite Tethyan marine δ¹³C_carb curve, several conclusions can be drawn: (1) the δ¹³C_plant record indicates that the atmospheric carbon reservoir was affected; (2) the defined ammonite correlations between Europe and Crimea are synchronous; and (3) a change in photosynthetic carbon-isotope fractionation, caused by a decrease in atmospheric pCO₂, occurred during the Upper Valanginian positive δ¹³C excursion. Our new data, combined with other paleoenvironmental and paleoclimatic information, indicate that the Upper Valanginian was a cool period (icehouse) and highlights that the Cretaceous period was interrupted by periods of cooling and was not an equable climate as previously thought.     

Tasks and functions of a decision support system for water resources management in the Lower Volga

The Lower Volga is a Russian region, which has a unique natural resources and a territory which is the area of collision of the interests of different economic branches that use water resources. The economic development of the region requires effective water resources management in harmony with natural conditions and the operation of the Volga-Kama reservoir system. A reliable management tool is a computer decision support system for the Lower Volga. The problems to be solved with this system answer the current water problems of the region. Data on the programs under implementation and to be developed are given; water apportioning model is given; and the way of coordinated choice of management regime of the Volga-Kama reservoir system and water resources use in the Lower Volga is demonstrated.     

Variations of δ<Superscript>18</Superscript>O in Rivers of Crimea in Winter

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.     

Ecologically Tolerable Impact Levels of Abiotic Factors in Water Bodies in Russia and Neighboring Countries: Dependence on the Geographic and Climatic Conditions

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.     

Seismogenic deformations in the walls of the late medieval Yeni-Kale fortress in Eastern Crimea

The results of a macroseismic study of the late medieval Turkish Yeni-Kale fortress in Eastern Crimea are described. Despite the fact that the fortress’ structures were considerably affected by local landslide activity, military operations during the Crimean War, the Civil War, and the WWII, as well as by anthropogenic factors, such as railroads, etc., numerous specific deformations in the fortress walls suggest that the existing destruction and damage might be explained by strong seismic impacts. The local intensity of seismic oscillations could be I = (VIII)–IX points according to the MSK-64 macroseismic scale, and the direction of the combined maximum seismic impact could have a NW–SE strike. It is likely that the Turks abandoned the fortress without a battle because of its significant seismic damage and destruction in the 18th century, which had not yet been repaired by the time the Russian army arrived.