Siverskyi Donets Research Articles

Elevation modelling of an area of the Siverskyi Donets riverbed (near Haidary village, Chuguyevskiy district, Kharkiv region)

Formulation of the problem. The article represents the practical experience of the bottom echo sounding and processing of the data received for digital elevation modelling. The relevance and specificity of using sonar equipment to study the specificity of the morphology of the underwater relief of small hydrological features are covered. The domestic and foreign publications in this area are analysed, and therefore the conclusion of the issue being not studied enough in domestic sources is made. Methods. The analysis of literature sources on modelling the river network, visualization of relief models. The bathymetric survey data was used to compile a bathymetric map of the river and build a digital elevation model. The purpose of the article is sharing developer experience in making of digital elevation models of a section of the riverbed on the example of the Siverskyi Donets River (near Haidary village, Chuguevskiy district, Kharkiv region). Processing of measurement data received as a result of echo sounder surveys. Preservation and recording of general information received to expand the river bottom relief database. Provide an overview of the uses and applications of geoinformation technologies, determine the research prospects based on the developed digital elevation models. Results. The results of echo sounding and post-processing of the data received using specialized software are presented. The section of the Siverskyi Donets River in the area of the geographical educational and scientific station «Haidary» was chosen as the territory for the hydrographic research (Haidary village, Chuguevsky District, Kharkiv region). The field part of the research was conducted using the equipment of the material and technical basis of the Physical Geography and Cartography Department of the V. N. Karazin Kharkiv National University, for instance using the Lawrance Elite 7 TI chartplotter-echosounder with modern scanning modes CHIRP, DownScan, StrucureScan. Scientific novelty and practical significance. The specificity of creating and visualizing in the ReefMaster software package is covered in the article. A model of the bottom of the corresponding section of the Siverskyi Donets River and a depth map, which will allow the future analysis of the dynamics and the prediction of changes of the bed configuration, have been developed on the basis of the field work results. The advantages of using budget equipment and software for performing underwater relief studies of such hydrological objects are formulated. The novelty of the study is not only the use of the methodological foundations of digital modelling, but also the alternative classification approaches for describing the relief and conducting morphostructural analysis based on the GIS technologies.

Preliminary Assessment of Ecological Status of the Siversky Donets River Basin (Ukraine) Based on Phytoplankton Parameters and Its Verification by Other Biological Data

The river basin of Siversky Donets is of great scientific interest since this river runs through a territory with heavy industry (in particular, coal mining, chemical processing and metal industries). Within the basin, rivers of different sizes were explored (small, medium, large and extra-large) that flow through siliceous and calcareous rocks on the same elevation (lowland—below 200 m a.s.l.). Phytoplankton, as one of the Biological Quality Element, was used to perform the assessment of ecological status of the water bodies within the Siversky Donets river basin in 2019. The state monitoring program based on the updated approaches has been implemented in the river basin for the first time. The composition of phytoplankton species in the basin comprised 167 species (168 intraspecies taxa), mainly Bacillariophyta (63%) and Chlorophyta (22%) with the presence of other species (Cyanobacteria, Charophyta, Chrysophyta, Dinophyta and Euglenophyta). High species diversity and divisions amount are a distinctive property of the smaller rivers, while the bigger rivers show lower number of divisions. The “bloom” events, which are important ecological factors, were not detected in the Siversky Donets river basin. Algal species composition in plankton samples of the basin was identified and series of ecological parameters, such as habitat preferences, temperature, pH, salinity, oxygenation and organic water pollution according to Watanabe and Sládeček’s index of saprobity (S) trophic state and nitrogen uptake metabolism were analyzed. The ecological conclusions were also verified by a canonical correspondence analysis (CCA). The significance of the Canonical Correspondence Analysis (CCA) results was estimated of by a Monte-Carlo permutation test. The high concentrations of inorganic phosphorus compounds (permanganate index (CODMn)) and nitrite ions favored the diversity of Chlorophyta and Cyanobacteria diversity correlated with the levels of bicarbonate and CODMn. High diversity of diatoms was facilitated by the total amount of dissolved solids and chemical oxygen demand (COD). It was found that low water quality could be associated with conditions leading to predominant growth of the mentioned groups of algae. According to the analysis, the highest water quality was characterized by balanced phytoplankton composition and optimal values of the environmental variables. The sites with reference conditions are proposed for future monitoring.

Methodical approaches to the evaluation of surface pollution of water objects in the area of mining enterprises (on the example of Donetsk-Pridniprovsk region)

The most important component of ecologically safe development of natural and socio-economic systems is the use of nature, which involves the organization of water resources, which ensures sustainable development and for a long time retains sufficient water potential. The ХХІ century is characterized by significant negative changes in the natural environment caused by the uncontrolled use of natural resources, the development of industry and transport, which leads to increased water consumption and at the same time increase its pollution. This has been particularly noticeable over the last 50 years, when human impact on the planet's water cycle has reached a global scale. Deterioration of the ecological condition of surface waters is due to qualitative and quantitative depletion of factors of their formation, which in some cases makes it impossible to use them for economic purposes. Water quality of water bodies is formed under the influence of both natural and anthropogenic factors. As a result of human activity in reservoirs many anthropogenic substances of various degree of toxicity can arrive. The article attempts to assess changes in surface water quality over the past decade and to determine the degree of natural and man-made transformation of rivers in the region and the possibility of their self-restoration and stabilization of the ecological danger of the region. The existing methods of assessment of water bodies by chemical indicators used in the area of operation of mining enterprises are considered. In some methods, the assessment of water bodies usually reflects regional features rather than their own pollution. Calculations for the water basin river Siverskyi Donets are made and relevant patterns are established.

The Catacomb No. 74 of the Verkhnii Saltiv Main Burial Ground

The materials of the catacomb burial, investigated in 1988 by the expedition of Kharkiv Historical Museum under the leadership of V. H. Borodulin, located on the main site of the early medieval burial ground near Verkhnii Saltiv village (Verkhnii Saltiv Burial Ground-I, hereinafter — VSBG-I), are introduced into the scientific circulation. The catacomb had a long (6.3 m) and deep (5.05 m) dromos, in the western part of which the path of the re-entry into the burial chamber was fixated. The burial chamber, transverse to the dromos, contained the remains of three people (a man, a woman, and a teenage girl) who had traces of deliberate destruction committed in ancient times (Fig. 1: 1). Despite this, a rich burial inventory was found in the burial, which included: weapons (sabre, two chisel-axes); household items (two adz-hoes, a jug); personal jewelry (earrings, beads, bracelets, rings); toiletry (mirrors, toilet boxes); details of clothing; elements of a belt set; amulets. According to the elements of the belt set, this burial complex is dated by the second — third quarters of the 9th century. The main feature of this catacomb is the presence of a silver earring in it (Fig. 1: 13), which finds broad analogies in the Slavic-Avar antiquities of the Danube region. On the monuments of the Dnieper Left-Bank forest-steppe, similar earrings were found in the monuments of the Volyntsev culture of the second half of the 8th — early 9th centuries. A silver plaque-frame with an anthropomorphic image (Fig. 1: 12) is not typical for classical Saltiv antiquities, and it is stylistically close to the plaques from the Hungarian burial (burial No. 2) near Subotsi village (Ukraine, Kirovohrad Oblast). The presence of these items in the catacomb No. 74 testifies to the close contacts of the Alans of the Saltiv culture of the Siverskyi Donets basin in the second — third quarters of the 9th century simultaneously with representatives of the conquered Slavic tribes and with the ancient Hungarians, who were allies of the Khazar Khaganate.

Screening of legacy and emerging substances in surface water, sediment, biota and groundwater samples collected in the Siverskyi Donets River Basin employing wide-scope target and suspect screening

Siverskyi Donets is the fourth longest river in Ukraine and its ecosystem is heavily affected by numerous agricultural and industrial activities. An impact of the on-going armed military conflicts in the Eastern Ukraine to the overall pollution by the chemicals has been studied. Considering the uncontrolled activities in the catchment due to the conflict, there is a high demand to assess the contamination status of the Siverskyi Donets basin. In this study, the occurrence of the EU Water Framework Directive priority substances, selected physicochemical parameters and wide-range emerging contaminants were investigated in surface water, groundwater, biota and river sediments samples from 13 sampling sites in the river basin. The study included metals, inorganic, non-polar and polar organic contaminants. The wide-scope target screening of 2316 substances and suspect screening of 2219 substances revealed occurrence of 83 compounds in the studied samples. A few industrial chemicals such as plasticizers bisphenol A and DEHP, as well as flame retardant brominated diphenylethers were found to be potentially hazardous to the ecosystem, exceeding the established legacy environmental quality standards (EQS) or the provisional no-effect concentration (PNEC) values. River sediment samples contained traces of long-term banned chemicals such as polychlorinated biphenyls (PCBs) and degradation products of DDT (p,p'-DDD and p,p'-DDE). A simplified risk assessment based on comparison of measured concentration of the detected compounds against their (eco)toxicity threshold values from the NORMAN Ecotoxicology Database has been performed to aid their prioritization in future monitoring and, eventually, establishing the list of Siverskyi Donets River Basin Specific Pollutants. A comparison with the recent similar studies in the Dniester and Dnieper river basins in Ukraine has shown that the overall pollution by chemicals in the Siverskyi Donets basin is significantly lower.

FINDINGS OF BONE CHEEK-PIECES OF THE EARLY IRON AGE IN KHARKIV REGION

The paper characterizes the bone cheek-pieces found on the Siversky Donets basin in the Kharkiv region and dated to the pre-Scythian time and the Scythian Age. The typological attribution of products is carried out. Their chronological position has been clarified.
 The paper presents the analogies of the cheek-piece from the Pechenihy territorial community belonging to the pre-Scythian time (with some parallels of decor in the early Chornolissya time) and enable to date this product back to the end of the final Bronze — early pre-Scythian stage. In absolute data this may be close to the end (last decades) of 10th—11th centuries BC.
 The fragment of a three-hole cheek-peace from the Scythian settlement near the village Stari Valki is interesting. The edge of the object shaped as horse’s head according to the model «with the ear lied back» but the ear itself is not marked. Analogies to such cheek-pieces date back to the middle of the 7th—6th centuries BC. Two lower fragments of three-hole bone cheek-pieces decorated with hooves also come from Kharkiv region. Date of such objects is the 7th—6th centuries BC.
 Cylindrical ornamented object from the Scythian settlement on the territory of the Lubotyn territorial community is also considered. Similar products were occurred in the neighboring region (Bilsk hillfort).The set of features enable to talk about their belonging to the Iron Age.
 Finds of early Scythian bone cheek-pieces from the Forest-Steppe of Siversky Donets Basin illustrate the early history of the Scythian tribes of this region whereas the main part of local sites belongs to the middle and late periods.

Петрографический и элементный анализ керамики поселения Глубокое Озеро-2 (первые археометрические данные)

The paper highlights the first results of compositional (raw materials and technological) investigation of ceramic pastes from the Hlyboke Ozero–2 settlement of the Late Timber-Grave Culture — Post-Timber Grave Culture type in the middle flow of the Siverskyi Donets river. Petrographic analysis and energy-dispersive X-ray spectroscopy have been applied. This allowed to characterize traditions of ceramic pastes preparation within the site and to start developing the database of petrographic and chemical composition of the Late Bronze Age ceramics of the studied region. Obtained petrographic data (allocation of two petrogroups) have been confirmed by elemental analysis of clay matrix. Elemental analysis showed chemical and mineralogical similarity of the samples of the two first layers of the site and allowed to provide distinction of the third layer samples. Supposedly, this could be explained by the change of the place of raw clay procurement on that stage.

Forest typological and botanical features of «Mozh river valley» as the object of Emerald Network

Ecological and coenotic properties are given and the environmental importance of natural complexes of the Emerald Network of Ukraine «Mozh river valley» (UA0000299 Mozh river valley) in Kharkiv region is highlighted. The object is located in the valley of the Mozh River — a right-bank tributary of the Siverskyi Donets River (Don River Basin) and covers 12658.48 hectares; moreover this area has hardly undergone changes due to land reclamation measures. In addition, the emerald object includes the reserves of local significance «Mirgorodsky» and «Merefyansky», as well as the wetland «Zaplava r. Mzha». The investigated object currently represents a complex of various identified settlements from Resolution 4 of the Berne Convention (C1.222, C1.224, C1.225, C1.32, C1.33, C2.33, C2.34, D5.2, D6.1, E2.2, E3.4, E5.4, F9.1, F3.247, F3.4, G1.11, G1.36, G1.414, G1.51, G3.4232, G1.A1), which have natural-historical and geomorphological dependance. The main ecological and biotic features, areas and list of main plant species are given for them. In the studied area there are populations of rare species of vascular plants that have different sozological status. Annex I to Resolution 6 of the Bern Convention includes Jurinea cyanoides and Pulsatilla patens, and a number of species have state preservation status in Ukraine (Salvinia natans, Dactylorhisa incarnatа, D. fuchsia, D. majalis, Orchis palustris, Gladiolus tenius, Fritillaria ruthenica, Tulipa quercetorum, Stipa borysthenica, Pulsatilla pratensis) and at the regional level (Polygonum bistorta, Valeriana officinalis, Parnassia palustris, Veratrum lobelianum, Thelypteris palustris, Dryopteris cristata, D. carthusiana, Athyrium filix-femina, Chrysosplenium alternifolium, Comarum palustre, Carex pseudocyperus, Lycopodium clavatum, Orthila secunda, Rubus saxatilis, Dianthus stenocalyx). In case of increasing economic impact, the main conditions for the existence of natural complexes in this area is the necessity to streamline forest use, reduce the impact of a number of invasive tree and shrub species, and minimize the impact of drainage and plowing of floodplains. It is also necessary to regulate the stream of vacationers and reduce the degree of anthropogenic pressure on natural complexes.

Checklist of the flora of the vicinity of Balakliya (Kharkiv region, Ukraine): native and alien taxa, distribution of rare plants, new findings

For the first time, information on the flora of the Siverskyi Donets basin in the vicinity of Balakliya town (Kharkiv region of Ukraine) was summarized based on the comprehensive analysis of published data, herbarium material, and own field examinations. Field surveys were conducted during September 2015 and March-July 2016. The surveyed areas were located mainly in the valleys of the Sіverskyi Donets river and some of its tributaries within the former Balakliуa district. The conspectus of flora comprising 933 taxa of vascular plants (including 798 recorded during field surveys) has been prepared. In particular, 739 taxa of native and 194 taxa of alien plants were recorded. The habitats of 14 species from the Red Book of Ukraine were found. The locations of other protected, uncommon and new for the flora of the region plant species were also identified. Several taxa (i.e., some of the calciphytes like Astragalus albicaulis, Linum czernjajevii, Odontarrhena tortuosa subsp. cretacea, Scutellaria supina, and Silene supina) were found out of their previously known ranges. Newly established locations of some other species (e.g., Ephedra distachya, Onosma simplicissima, and Ornithogalum boucheanum) significantly complement previously known chorological data. Finally, information about new findings of such alien taxa actively expanding new areas as Cornus sanguinea subsp. australis, Fraxinus pennsylvanica, Sedum sexangulare, Ulmus pumila, and Vitis vulpina is provided.It has been established that the flora of the Siverskyi Donets basin in the vicinity of Balakliya town is a rich natural center of phytodiversity being under active adventisation. Forest reclamation plantations play a significant role in spreading the alien plants. Railway and the pine terrace of the Siverskyi Donets also serve the migration corridors for many of such alien plants.

СТРУКТУРА ЧАСОВИХ РЯДІВ РІЧНОГО СТОКУ ВОДИ РІЧОК БАСЕЙНУ СІВЕРСЬКОГО ДІНЦЯ НА ОСНОВІ СТОХАСТИЧНОГО АНАЛІЗУ ЙОГО БАГАТОРІЧНИХ КОЛИВАНЬ

To detect the cyclic component in time series of annual water runoff of rivers of the Siverskyi Donets River Basin structure, it is necessary to have a hydrological gauge, which closes a large river basin and has long continuous observations of water runoff. The only hydrological gauge that meets these conditions is the Siverskyi Donets – Lysychansk – the catchment area is 52,400 km2 and the beginning of observations of water runoff since 1892. The Siverskyi Donets – Lysychansk is quite intermittent. Analysis of annual water runoff data of “neighboring basins” for the Siverskyi Donets Basin showed that the longest series of continuous observations has a hydrological gauge the Desna River near Chernihiv – since 1895, the catchment area is 81400 km2. So, we can consider this basin as basic for calculations and determination of patterns of long-term variability of annual water runoff of rivers of the Siverskyi Donets Basin. The study used data from eight hydrological gauges: the Desna – Chernihiv, intermediate river basins – the Sula – Lubny, the Psel – Zapsillya, the Vorskla – Kobeliaky, within the study basin – the Siverskyi Donets – Lysychansk, the Bakhmut – Siversk, the Aidar – Novoselivka, as well as the Southern Bug – Oleksandrivka. To confirm the spatial consistency of the annual water runoff of the studied rivers, a correlation matrix between the time sequences of the water runoff of neighboring basins was determined. To obtain a generalized characteristic of long-term water runoff variability of the studied rivers, chronological graphs of changes in modular coefficients were constructed, initial time series smoothing was performed, graphical analysis of difference integral curves was applied. In the course of the research regularities in long-term variability of average annual water runoff of rivers of the Siverskyi Donets Basin were identified, cyclic component was identified, duration and nature of water runoff cycles and within them low and wet phases were identified. The prediction of annual water runoff in the near future was done. Joint autocorrelation and spectral analysis allowed to identify a mutually confirmed cycle lasting 19-24 years for the rivers of the Siverskyi Donets Basin. According to the criterion of series, it is established that the periods of low phase can be 9±2 years. Knowing the length of the cycles, water-specific phases were identified. As a result, for the rivers of the Siverskyi Donets Basin it was found that the runoff in the wet phase exceeds the norm by an average of 18%, and the runoff in the low phase is lower by an average of 17% than normal. Therefore, the difference in river water phases is ≈ 35%. Forecast estimates show that by 2020±2, the rivers of the basin will have a low phase, which began in 2008. A wet phase is expected from 2020±2 to 2029±2, then in the period 2030±2 – 2038±2 years – low phase. In the period from 2039±2 to 2048±2, we should expect an increase of annual water runoff of the rivers of the Siverskyi Donets Basin.

Ecological changes in geological media and Siverskyi Donets River basin under the condition of goal mines flooding

Complex economic, geological-technological state of coal mines and impact of the armed conflict factors (the breakdown of energy supply, objects of critical infrastructure, etc.) accelerated closure of coal mines by the method of “wet preservation” in particular. In most developed EU countries decommissioning of coal mines, which have great depth (up to 1,0-1,5 km) and areas of minefields, occurs according to the post-mining (PM) research and production complex, which is based on the scientific and technological activities regarding prevention of dangerous changes in the geological environment (GE) - subsidence of ground surface, lands flooding, emission of explosive and toxic gases as well as reduction of outflows of polluted water into the local river basins (RB) and the soil aquifer. Additionally, PM suggests some mining works turning into the hydraulic-filtration system of mine water retention at a depth of 250-350 m with a purpose of preventing pollution flow into the freshwater aquifers and river network, preserving regional aquitards, degassing of mountain surface. In general, the PM activities complex aims at maintaining the balance and protective potential of the GE as mineral and landscape basis of the biosphere, elimination of dangerous changes in ecological parameters of the hydrographical network. It is shown that new models of subsoil and water use, geological prospecting structure, scientific basis for permissible changes in GE and RB are required together with closure of “old” mining works (MW) and opening of new ones, improvement of the environment monitoring based on GIS technologies and Earth remote sensing.

GIS Modelling of the Distribution of Terrestrial Tortoise Species: Testudo graeca and Testudo hermanni (Testudines, Testudinidae) of Eastern Europe in the Context of Climate Change

The study of the distribution of protected animal species in Europe is especially relevant in a changing climate. Therefore, in this work, we tried to solve the problem of the possibility of habitation of tortoises Testudo graeca Linnaeus, 1758 and Testudo hermanni Gmelin, 1789 in Eastern Europe by using species distribution models (SDMs). We used bioclimatic variables from the CliMond dataset (18 uncorrelated variables of 35) and 19 Paleoclim variables of the “early-Holocene” and “mid-Holocene”. Packages Maxent and 'ntbox' were employed. In addition to our data, we used findings listed in the GBIF databases: 1,935 points for T. graeca and 991 points for T. hermanni. It has been shown that subspecies of tortoises differ in the characteristics of the ecological niche. In addition to direct anthropogenic influences, the limiting factor is the “Mean temperature of coldest quarter” (bio11) for both species. Moreover, T. graeca is less demanding and can tolerate both frost and higher temperatures during drier periods than T. hermanni. Modeling found that in the future it is possible for these species will expand in a north-eastern direction, where potentially suitable habitats will appear: by 2090 in the South of Ukraine (Odessa region, Crimea) and East Ukraine (floodplain of the Siversky Donets River of the Don basin).

THE DONETSK NEOLITHIC CULTURE SITE OF BONDARIKHА II

The Neolithic site Bondarikha ІІ was explored 70 years ago by D. Ya. Telegin. The materials of the site were not processed utilizing modern methods. The authors of the paper re-examined and analyzed the site’s materials using current methodologies.
 The Bondarikha II site is set along a natural boundary on what is now the south-eastern outskirts of the modern city of Izium, Kharkiv region. The location of the site is a section of an over-flooded terrace that stretches along the left bank of the River Siversky Donets, and a section of an older river bed named the Willow Pit. In the north, sections of the terrace were crossed by an unnamed stream, and its southern boundary defined by floodplains. The lowlands nearest the terrace are primarily comprised of wetlands.
 It is quite clear that the Willow Pit was once an active river and seasonally may have transformed into a lake during times of flooding. The site is located approximately 7 m above the current floodplain. The general site position is typical for the Neolithic sites of Donetsk Culture, with the vast majority of which are located on terraces above the floodplain lakes of Siversky Donets, with the habitational remains occupying the highest areas of terraces, or the periphery / edges of such terraces.
 The interpretation of Bondarikha material culture was quite simple. The presence of pencil-like blade cores, oblique truncated points of the Abuzova Balka and Donetsk types, a series of blades displaying abrupt retouch on edges, along with bilateral burins, scrapers on flakes, and ovate axes are attestation that the assemblage and complex are connected with the advanced stages of Donetsk Culture.
 The estimation of the site’s age is possible only by the principles of relative chronology. The Mariupolian origin of the trapeze projectiles allows us to establish the earliest age range of the complex within the beginning of the VI millennium BC. However, the utilization of trapeze projectiles with flat dorsal retouch that spread in the basin of Siversky Donets in the third quarter of VI millennium BC is not present. Accordingly, we can safely place the age of the site within the first half of VI millennium BC.

MATERIALS FROM RESEARCH OF O. G. SHAPOSHNIKOVA AND D. YA. TELEHIN IN THE STAROBILSK DISTRICT, LUHANSK REGION

MATERIALS FROM RESEARCH OF O. G. SHAPOSHNIKOVA AND D. YA. TELEHIN IN THE STAROBILSK DISTRICT, LUHANSK REGION

Assessment of the water pollution level and the environmental status of rivers in the Siverskyi Donets basin by BOD5

The paper topicality consists in the necessity for determination of the environmental status of the rivers in the Siverskyi Donets Basin and assessment of the possibilities for them to achieve ‘good environmental status’ under the modern climatic conditions and the anthropogenic load. Siverskyi Donets is the main river in the Eastern Ukraine. There are large industrial zones at the water catchment area. Among them, there are the Donetsk Coal Basin and the industrial complexes within the City of Kharkiv, which have exerted influence on surface water quality for decades. A method for assessment of the pollution level and the environmental status of waters by the hydrochemical index of BOD5 (biochemical oxygen demand for 5 days) is used in the paper.
 The paper is aimed at identification of the main trends in water quality changes by hydrochemical index of BOD5. The object of research is a pollution of the rivers at the Siverskyi Donets Basin by industrial, municipal and mine wastewaters. The subject of research is an assessment of water qualitative status by BOD5.
 The hydrochemical observation data for 7 gauges at the main river and 7 tributaries for the period of 1990-2015 were used in the paper. The major attention is focused on the most polluted rivers in the Eastern Ukraine: the Udy and the Kryvyi Torets. The quality of the Udy River water is largely determined by the municipal wastewater from Kharkiv. The Kryvyi Torets River belongs to the Donbas rivers, where pollution by mine water and wastewater from industrial enterprises is significant.
 Pollution levels, environmental status and saprobity were determined by the average annual indices of BOD5. Empirical probabilities for occurrence of a certain pollution parameter at various gauges were calculated for comparative analysis.
 It is found that a BOD5 downward trend has been prevalent on the rivers at the Siverskyi Donets catchment area in the early 21st century. The highest BOD5 values were observed on the Donbas tributaries and the Udy River (downstream from the City of Kharkiv), as well as upstream and downstream from Lysychansk, and the lowest ones were observed on the Oskil River.
 It is also revealed that in the early 21st century, the main river water has a ‘threshold’ environmental status (β-mesosaprobic zone), except for the Lysychansk gauge, where the status is ‘irreversibly altered’ owing to the inflow of polluted water from Donbas rivers into the Siverskyi Donets.
 Research into the Udy River water quality upstream and downstream from the industrial city of Kharkiv has shown that the water in the upper reaches of this river is classified as ‘clean’ and ‘moderately polluted’, and the environmental status may become ‘good’ in the future. Downstream from the city, the water is mostly ‘dirty’, and the environmental status is ‘irreversibly altered’, which corresponds to the α-mesosaprobic zone. For the Kryvyi Torets River (the Donbas Region), owing to the impact of organic pollution, the environmental status is defined as ‘threshold’, ‘irreversibly altered’ and it has begun to deteriorate in recent years.
 To improve the environmental status of the Donbas rivers, the reduction in discharges of untreated municipal and industrial wastewater into surface watercourses, as well as the construction of state-of-the-art sewage treatment plants are necessary.

Patterns of vegetation succession in abandoned fields in semi-arid conditions

Successions in old fields were studied on the example of the Starobilski steppes within Luhansk Oblast (Ukraine), region located in the basin of the left tributaries of the Siversky Donets, in the southern spurs of the Central Russian Upland. Stationary surveys were conducted in the Striltsivsky Steppe affiliate of the Luhansk Nature Reserve, with 269 ha of old fields (26% of the area) in its territory. Geobotanical releves were performed in 26 plots of abandoned fields, constant monitoring surveys were carried out in 15–27 year-old abandoned fields in the territory of the Reserve and 5–15 year-old abandoned fields in the territory of its buffer zone. In total, the itinerary and detailed surveys were conducted for about 50 plots of abandoned fields. The restoration of the steppe communities was seen only in the plots where grazing and/or mowing took place, which prevented the formation of dense litter and distribution of woody species. The long domination of rhizome grasses (Elytrigia repens) were characteristic in conditions of moderate-level disturbance (in the reserve), transition to the domination of bunchgrasses (Festuca valesiaca) was seen at the age of around 25 years, during the transitional period (20–25 years) communities with unstable structure formed, comprising E. repens, F. valesiaca and forbs (Achillea pannonica and Fragaria viridis). Duration of the stage of segetal and ruderal species in the sites under low effect was 10 years, the communities of unstable structure formed at the age of 5–10 years. In the conditions of stable moderate and high effect of grazing (high disturbance), we observed formation of bunchgrass communities at the age of 15 years. In the unused plots, we saw formation of phytocoenoses of shrubs at different stages of succession, starting from 10 years. The most abundant group of such kind comprised thickets of Ulmus pumila (with E. repens and Poa angustifolia in the herbaceous layer) and Prunus stepposa. The peculiarity of contemporary processes in the abandoned fields related to exacerbation of the vegetation’s anthropogenic transformation is distribution of alien tree species from plantations, the most aggressive of which are Ulmus pumila, Fraxinus lanceolata, Acer negundo, Elaeagnus angustifolia. The peculiarity of the succession processes in the region of studies was the domination of species of broad ecological spectrum, characteristic for abandoned fields of northern forest-steppe regions (Bromopsis inermis, Calamagrostis epigeios, Poa angustifolia, Fragaria viridis) and southern steppe regions (Bromus sguarrosus, Anisantha tectorum, Achillea pannonica, Artemisia austriaca), certain communities form dependent on the climatic conditions and type of land use in the period of succession in particular plots.

Household Buildings of Vovchansk hillfort: Their Reconstruction and Interpretation Problems

Vovchansk hillfort is located in the eastern border area of Vovchansk city in Kharkiv Region. It belongs to the Saltiv archaeological culture (mid. VIII — mid. X centuries), which reflects material and cultural remains of the Khazar Khaganate. This site is among one and a half dozens of microregions in the Khazar Khaganate located in the middle stream of the Siverskyi Donets. The site is located on the cape of the right bank of the Vovcha River (right inflow of the Siversky Donets). It has one yard with a threefold defence system that includes earthen walls, ditches and scarps. Household buildings were discovered in the northern part of the citadel, and between outward and inward defensive lines. A small household zone was found within the range of the space near citadel walls; its household buildings were of a small area, with mud-brick walls. They were likely to serve for food supply storage meant to be delivered for a small number of consumers (for example, for the citadel garrison). Nine household buildings found between exterior and middle defence lines were investigated in the southern part of the hillfort; they are located in 4.0—6.0 meters from one another (in the absence of nearby dwellings). All of them are different in their plan and construction. The reconstruction of the most extant ones is offered in the article. The following things were taken into account: results of archaeological research, construction quality of grounds, surrounding nature of construction raw materials, presence of implements and their feasibility of raw materials processing, and also ethnographic data on traditional construction of the population in XVIII—XIX centuries. These buildings were designed for food preservation in wooden or vine- or fibre-braided baskets and other containers, also in bags (of leather or tissue) and ceramic tare. As to the purpose of these food stocks, some hypotheses are offered. The 1st hypothesis: the storage could belong to the local surrounding population in the times of external threat for the residents of the nearby settlements; it seems probable in the light of the civil war in Khazaria at the beginning of the 9th century. The 2nd hypothesis: food supply could be stored to be consumed by the garrison, which could be located in the hillfort citadel for creating military pressure on the Slavs. The 3rd hyposesis: the mentioned buildings could be used for temporary retention of the corn harvest (and probably, the Slavs’ tribute) reaped by the local community before its shipping at the disposal of the central authority of the Khaganate. Similarity between two discovered household buildings in the excavation site No. 3 points to the fact that the work was done by the same craftsmen group following the common plan. Constructive diversity of household buildings in the excavation site No. 4 shows that they were created by different craftsmen groups.

Predicting deformations in the area of impact exerted by a bridge crossing based on the proposed mathematical model of a floodplain flow

To develop the methods for predicting deformations on floodplain areas in the zone of influence of bridge crossings, a mathematical model of a suspended flow with grass vegetation was developed. The problem of calculating the hydrodynamic fields of velocities and pressure in artificially compressed flows refers to the theory of shallow water since the vertical size (flow depth) is substantially smaller than the horizontal dimensions, such as length and width. In accordance with this, the proposed model is based on the equation of distribution of velocity structure and the depth of a floodplain flow in approximation to two-dimensional dependences taking into consideration force factors. Force factors determine resistance at flowing around vegetation in floodplain areas and resistance of washout of fine-grained soil. To obtain an unambiguous solution of the considered problem, boundary and initial conditions were added to the presented closed system of original equations. These conditions make it possible to determine the level of a free surface of flow and the zone of influence of a bridge crossing at different stages of the estimated flood. Based on finite-difference analogs of transfer equations, the distribution of velocities and depths in estimated sections was calculated. By iteration, the longitudinal velocity in a flood flow with vegetation elements was determined. The results of the calculation of washout on floodplain areas of a sub-bridge watercourse of the lowland river Siversky Donets were obtained. The depth of a flood flow after a washout was determined based on the ratios of actual and flood-free velocities. When compared with the initial bottom marks, the washout of the larger floodplain is 0.96 m, that of the smaller floodplain – 1.28 m. The proposed scientifically substantiated solution for ensuring optimum interaction of floodplain flows with bridge crossings makes a certain contribution to improving the reliability of their operation due to the quality of design works and the corresponding reduction of construction and operating costs

The European mole (Talpa europaea) in the Siversky Donets region: new data on the species’ distribution in Luhansk Oblast, Ukraine

New data on the distribution of moles in Luhansk Oblast are presented. Field studies were carried out in 2008–2019. The European mole is a sporadic and non-abundant species in the studied area. In Stanychno-Luhansk Raion, the species first appeared in the late 1990s. In some years, moles in the region are characterised by fluctuations of the population number and geographic range. Additional field studies are required to clarify the European mole's range and abundance in Luhansk Oblast.

Speciation of Zn and Cu in Technosol and evaluation of a sequential extraction procedure using XAS, XRD and SEM-EDX analyses.

Metal speciation, linked directly to bioaccessibility and lability, is a key to be considered when assessing associated human and environmental health risks originated from anthropogenic activities. To identify the Zn and Cu speciation in the highly contaminated, technogenically transformed soils (Technosol) from the impact zone near the industrial sludge reservoirs of chemical plant (Siverskyi Donets River floodplain, southern Russia), the validity of the BCR sequential extraction procedure using the X-ray absorption fine-structure and X-ray powder diffraction (XRD) analyses was examined after each of the three stages. After the removal of exchange and carbonate-bonded Zn and Cu compounds from Technosol (first stage of extraction), the resulting residual soil showed enrichment in a great diversity of metal compounds, primarily with Me-S and Me-O bonds. The number of compounds with a higher solubility decreased at the subsequent stages of extraction. In the residual soil left over after extracting the first and second fractions, the dominant Zn-S bond appeared as würtzite (hexagonal ZnS) that made up more than 50%, while the Cu-S bond was almost completely represented only by chalcocite (Cu2S). The XRD analysis revealed the authigenic minerals of metals with S: sphalerite (cubic ZnS), würtzite (hexagonal ZnS), covellite (CuS) and bornite (Cu5FeS4). The scanning electron microscopy data confirmed that würtzite was the dominant form of Me with sulfur-containing and carbonate-containing minerals. The Zn-S bond was the main component (57%), whereas the Cu-O bond was dominant in the residual fraction (the fraction after the third-stage extraction). The results revealed that the composition of the residual fractions might include some of the most stable and hard-to-recover metal compounds of technogenic origin. Thus, the application of the novel instrumental methods, coupled with the chemical fractionation, revealed the incomplete selectivity of the extractants in the extraction of Zn and Cu in long-term highly contaminated soils.