ISSN 2367-6671 (Online)
PROBLEMS OF GEOGRAPHY
Dimitar Antonov, Tsvetan Kotsev, Nathalie Van Meir, Velimira Stoyanova, Zvezdelina Aidarova – Arsenic migration analysis in polluted riverine terraces during flooding event – innovative modeling approach using HYDRUS-1D code
Antonín Vaishar, Jana Zapletalová, Petr Dvořák, Dilyana Stefanova, Emilia Tcherkezova – Recent population development in sensitive karst areas: case studies Moravian karst (Czech Republic) and Devetaki plateau (Republic of Bulgaria)
Sha Yu, Li Xiaomei, Rumiana Vatseva – SYNTHETIC EVALUATION OF ECO-ENVIRONMENT BY ENTROPY WEIGHT METHOD
The application of entropy in environmental studies aims to determine theweights of environmental factors for evaluation of eco-environment so as to carry out synthesized evaluation. We can take entropy as index of information for eco-evaluation. Every characters of the subject-object of ecosystem can be measured with entropy to get their information. The interaction between factors of function of entire ecosystem, production and stability can be indicated by information entropy of relation between factors, because the entire ecosystem can be explained with its composing. In this article, as the main contribution, an evaluation of a region‘s eco-environment is performed by means of entropy weight method and the whole used technology is presented.
Keywords: Eco-environment, Synthetic Evaluation, Entropy Weight Method
Dimitar Antonov, Tsvetan Kotsev, Nathalie Van Meir, Velimira Stoyanova, Zvezdelina Aidarova – ARSENIC MIGRATION ANALYSIS IN POLLUTED RIVERINE TERRACES DURING FLOODING EVENT – INNOVATIVE MODELING APPROACH USING HYDRUS-1D CODE
The paper presents an algorithm for modeling the vertical water transport of arsenic (As) in contaminated river floodplain deposits using the software product HYDRUS-1D. A scenario of river flooding is prepared with sample data from a model plot in the Ogosta River valley, northwestern Bulgaria. Meteorological and hydrological data were also used for the historical flood, which happened in April 1964. The soils in the valley are heavily polluted with arsenic and heavy metals as a result of historical extraction and flotation of Fe- and Au-ores in the region of the town of Chiprovtsi. The study site of P13 is situated in the valley section between the village of Belimel and the Ogosta dam lake at 13 meters fromthe river bank in the low floodplain with a vertical distance to the river bed of 169 cm. The concentration of arsenic in the soil ranges between 625-11450 mg/kg for individual layers to a depth of 170 cm. The sediments are built of loamy sand, and gravel with loam sandy to sandy filler. The simulation of water and As transport encompasses a seven-day period in which the soil is flooded on the fourth day. The flooding event itself is implemented into the model as a water flux leading to 74 cm flood above the surface. Separate transport simulations of As (V) and As (III) were made for the same soil profile. The values used for the distribution coefficient Kd are determined according to the literature and are respectively Kd As(V) = 2000 l/kg and Kd As(III) = 5 l/kg. The modeling results show that the flood water flow passes for one day across the entire depth of the profile. The soil layers are water-saturated during the flood. The amount of water which passed through the profile for the modeling period is 2500 l/m2. The transport simulation of As (V) calculates an entry of 800 mg/m2 of the pollutant at a depth of 170 cm for the whole seven day period at an average concentration of As (V) in the porewater of 0.409 mg/l. The calculated amount of As (III) which infiltrated to the bottom of the profile for the same period is 870 g/m2. It is more than 1000 times higher than the estimated quantity for As (V). Constraints of modeling are the constant groundwater level during the flood, the use of an average Kd distribution coefficient of arsenic for a wider set of soil varieties, and the recondition of only As (V) or As (III) existence in the soil solution during the transport simulation. Despite the limitations and conventions of the As transport modeling with HYDRUS-1D, the results show the significant role of the river floods for the arsenic infiltration from the contaminated soil layers into the groundwater. The presented detailed algorithm for water and mass modeling enables the use of HYDRUS-1D for scenarios withdifferent flooding duration and different depth of ground water table.
Keywords: HYDRUS-1D, flooding, groundwater, monitoring
Lidiya Semerdzhieva, Rumen Penin, Tanya Stoilkova – ECOGEOCHEMICAL RESEARCH IN THE LOWER PART OF THE PROVADIYSKA RIVER
The paper presents the contemporary landscapes and their geoecological condition in thel ower part of the Provadiyska river catchment basin. Using landscape-geochemical research methods, the specifics and the conditions of migration and differentiation of heavy metals in selected plants and river (bottom) sediments have been revealed. The results are compared with those of similar research, carried out in the above-mentioned area 20 years ago. Analyzes and comparisons with other biоgeochemical studies in Bulgaria and abroad have been done.
Keywords: geochemistry, landscapes, heavy metals, biogeochemistry, catchment basin,
Kristina Gartsiyanova – GROUNDWATER STUDIES IN BULGARIA
Groundwater systems have been the subject of research since ancient times. This article reviews the groundwater studies carried out to date in Bulgaria. It has been established that in the course of the researches carried out from ancient times to the present day, the following directions of scientific research interest have been gradually formed – hydrogeology and groundwater regime, mineral waters, karst groundwater, hydrochemistry and ground water pollution, groundwater modeling, some authors have recently dealt with the
issue of European and national legislation.
Keywords: studies, groundwater in Bulgaria
Vоlоdimir Vorovka – CLIMATE CHANGE AND ITS EFFECTS FOR THE UKRAINIAN PART OF THE AZOV SEA COAST
The purpose of this paper is to study indices of the regional climate change, its impact on environment and possible future effects. The results were obtained by analysing data of long-term observations of climate indices at the Melitopol meteostation and hydrometeostations of Henichesk, Botievo, Berdiansk. Among climate indices, dynamics of the average annual, maximum and minimum air temperatures, sum of active temperatures above +15°C, precipitation amount and its patterns, changes in wind speed, and changes in wind circulation processes are analyzed. It is established that the increase in the average annual air temperature is accelerating: in the second half of the 20th century the increase constituted 0.8°C, and from the beginning of the 21st century, the growth rate is estimated as 1.95°C for 100 years. In the period from 1951 to 2014, an increasing trend of the average annual air temperature at the Melitopol meteorological station was 1.7°C, thus reaching the value of +11.5°C. Most of the increase was observed in the period since 1990. The last two decades were the hottest in the history of climate observations. The rise of the average annual air temperature up to 12.3-12.5°C by 2050 is predicted. An analysis of long-term values of the sum of positive temperatures above +15°C shows an increase of 40°C per year, with a rapid growth of this index in 2008-2012 – to 80°С per year. During 2005-2017, compared with the period before 2005, the minimum and maximum air temperatures at the Melitopol meteorological station increased: the minimum temperature ranged from -33°С to -26.3°С (23.01.2006), and the maximum was from +40°С to +41°С (07.08.2010). A gradual increase in the amount of precipitation occurs against rising extremes of their patterns between years. According to the trend line, the increase in the amount of precipitation to 550-560 mm is predicted by 2050, thus being 100 mm higher than the long-term climate norm for Melitopol (460 mm). Redistribution of the precipitation amount towards the cold season is associated with changes in wind circulation processes over the territory with a gradual increase in the western component of the flow. The warm season is becoming hotter and drier. Tendencies to a significant decrease in wind speed are revealed. Compiled wind roses indicate further rearrangement of atmospheric circulation over south-eastern Ukraine towards the western component. An analysis of possible effects of climate change and their high intensity on the soil and vegetation cover, landscapes and agrarian sphere of human activity is given.
Keywords: climate change, sum of active temperatures, wind circulation, precipitation
amount, changes in wind circulation, effects of climate change, human adaptation to climate warming.
Antonín Vaishar, Jana Zapletalová, Petr Dvořák, Dilyana Stefanova, Emilia Tcherkezova – RECENT POPULATION DEVELOPMENT IN SENSITIVE KARST AREAS: CASE STUDIES OF THE MORAVIAN KARST (CZECH REPUBLIC) AND THE DEVETASHKO PLATEAU (REPUBLIC OF BULGARIA)
The paper is aimed at analysing the recent population development sensitive areas, comparing two karst areas – one in the Czech Republic and one in the Republic of Bulgaria. Methodologically, crude data from population balances and population censuses were used. The Moravian Karst is an area situated in the vicinity of Brno – the administrative center of Moravia region, and, therefore, is subjected to suburbanisation processes, which puts the Moravian Karst area under pressure by urbanisation and tourism on the one hand, “fighting” with landscape protection on the other hand. Although this rural territory is unsuitable for intensive agricultural production, it does not really mean it is uninhabited, nor does it mean it is depopulated. The Devetashko Plateau on the other hand is a plateau situated in the vicinity of Lovech – a city ten times smaller than Brno in terms of population number. Commuting in that area is more difficult, regarding the age and qualification structure of the population, as well as the existing transport conditions. The micro-region is depopulated, while population aging is extreme. The differences between the compared areas are the result of their geographical location, level of dependence on primary economic activities and socio-historical development. The aging processes are highly likely to continue in the future. In the Moravian Karst area, the population development is slow, which makes it easier to cope with. The drawdown of some settlements in the Devetashko Plateau area was rapid and too deep, to a point where hardly any remedies are possible. The following factors have been suggested to have the greatest impact on the rural depopulation: the overall population development in the country, the vicinity of a regional center, the state of the urbanisation processes, the level of dependence on the primary economic sector, the efficiency of the transport systems, the excessive cultural diversity, as well as some other individual circumstances.
Keywords: depopulation, Moravian Karst, Devetashko Plateau, Czech Republic, Republic
Tzanko Tzankov, Rosen Iliev, Svetla Stankova, Ilia Mitkov – CENTERS OF MAXIMAL CONTEMPORARY ELEVATION AS A REAL CRITERION FOR THE RELIEF ROUGHNESS ASSESSMENT
Relief roughness is one of the main morphostructural features of the local topography. It is a basic methodological tool of regional morphostructural analysis and is the basis for various comparative studies. The main goal of this study is quantitative description of complexity of relief roughness based on the CMCE (Centers of maximal contemporary elevation). CMCE mark the highest elevated parts of the local dome-like morphostructures, which represent the basic aspect of the local relief. In this way they are a real criterion for the relief roughness evaluation. On this basis in the present work a new principle approach is proposed. The main features of the new method, as well as the ways of assessment and application are described.
Keywords: relief, roughness, dome-like, morphostructures, centers, elevation, method
Dimitar Parlichev – GEOMORPHOLOGY OF THE MORPHOSVERIC BASINS AND TECTONICS OF THE LYTHOSPHERIC PLATES
Geomorphology has not produced a general theory. In contrast, geotectonics has its Plate tectonics, adopted by the vast majority of geologists as a general theory of geology. It emerged after geophysics revealed the structure of the Earth’s crust, a solid lithosphere of continental and ocean type over a plastic astenosphere. And after exploring the ocean and sea floors and studying their peculiarities – the mid-ocean ridges, their symmetrical magnetic anomalies, linear elongated deep-water grooves marking the subduction of the tectonic plates, the ocean-bed movement (spreading) and revealing the mechanism of their formation.
Meanwhile, in geomorphology, mostly Russian, a number of publications have been reported to establish key global laws, for example: the endogenous processes create the prevailing roughness of the Earth’s surface, primarily the continents and oceans; on a planetary scale, their activity is totally commensurate with that of exogenous processes destroying this roughness; the rising mountain areas are intensely denuded – a process that makes them lighter thus assisting their rise; the sediments conveyed from the continents to the ocean floor accumulate mainly in the sinking abyssal grooves, which facilitates the subduction and thus the movement of the tectonic plates; in fact, a geodynamic flow of ocean floor motion is carried out under the influence of the plastic masses in the astenosphere towards the continents and the rise of the latter and a quantitatively equivalent morpholythodynamic flow of ground mass movement in the opposite direction sinking the continents under the action of the hydrosphere, atmosphere and the biosphere, driven by solar energy; it has recently become clear that the morpho-lythodynamic flow takes place within the socalled morphospheric basins falling entirely within the boundaries of the morphosphere (the area of hypergenesis) – the topmost part of the lithosphere; it becomes increasingly clear that if the lithosphere, lithospheric plates, and geodynamic flow are the object and subject of geotectonic research, the morphosphere, morphospheric basins, and morpholythodynamic flow can be the object and subject of geomorphology alone. It follows that the relief paradigm as a product of the interaction of endogenous and exogenous processes must be replaced by the morphospheric paradigm as such product (the relief is only an element, the upper limit of the morphosphere). And also that the geodynamic and morpholythodynamic flow pairs, lithosphere and morphosphere, lithospheric plates and morphospheric basins and geotectonics and geomorphology respectively, and their theories are related to each other as both sides of the same coin. This requires a paradigm shift from division between endogenous and exogenous forces to their interaction in building the earth’s crust and maintaining its isostasis. Which implies the addition of the Plate tectonics to the basins geomorphology to make it a complete general theory of geology.
Keywords: plate tectonics, lithosphere, lithosperic plates, geomorphology of the basins,
morphosphere, morphosperic basins.
Irena Aleksandrova, Plamena Raykova, Emil Oynakov – SEISMIC ANALYSIS OF THE 26TH NOVEMBER 2017 EARTHQUAKE IN THE TOWN OF KLISURA, BULGARIA
The seismic analysis of the earthquake of 26 November 2017 with magnitude Mp4.1, realized in the area of Klissura, is presented. The spectral characteristics of the earthquake are explored using the Brune model. Applying this model, features associated with the earthquake source, such as the stress drop (Δσ), the source radius and the seismic moment (Mw) magnitude, are determined. A detailed study of the macro-seismic field of impacts is presented for the earthquake. The Micro Seismic Drilling Method for the observed event is also applied.
Keywords: intensity, magnitude, spectral characteristics, microseisms
Davis Dinkov – 3D MODELING OF CULTURAL HISTORICAL HERITAGE SITES USING UNMANNED AERIAL SYSTEMS
Technologically advanced tools such as Unmanned Aerial Systems (UAS) permit users to collect up-to-date high quality imagery of cultural and historical monuments. Experts have explored the use of UAS for creating 3D models of individual historical monuments or complexes of buildings and facilities. In order to demonstrate the suitability, reliability and precision of the technology, this paper describes approach used to acquire aerial images with DJI INSPIRE-1 quadcopter to create image mosaics, 3D point clouds and 3D image models. The selected case study is the memorial complex – the monument of Okolchitsa peak in the “Vrachanski Balkan” Nature Park, which is consisting of a high vertical object – opulent cross with a height of 26,60m and a building of the Chapel of St. George. The approach of stairs to the monument, as well as the surrounding area, is also included in the tested area. The output results are obtained by applying a Structure from motion (SfM) method using Pix4Dmapper software package for digital image processing and 3D modeling. The deliverables include the following digital products: orthophoto mosaic, digital surface model (DSM), digital terrain model (DTM), 3D model and 3D visualization of the historical monument. Our results demonstrate applicability of low-cost UAS to obtain digital data of sufficient quality to meet photogrammetric standards by acquiring of multiview imagery suitable for SfM processing and the creation of 3D models of adequate geometric accuracy for the management and monitoring of cultural and historical heritage sites.
Keywords: 3D modeling, UAS, SfM method, cultural historical heritage sites, Vrachanski
Balkan Nature Park.
Dimitar Parlichev – A METHOD FOR WATER AND ATMOSPHERIC СО2 REDUCTION
The paper emphasizes the aggravated international situation caused by the accelerated global warming of the atmosphere, concurrent with the less effective governmental response to limiting the greenhouse gas emissions. There is no objective assessment of the real danger and extreme action on all sides against the approaching global catastrophe predicted by a group of scientist to begin in 2021. The traditional engineering methods for direct absorption of the CO2 from the atmosphere are considered prohibitively expensive and largely inapplicable. The proposed method is to extract the CO2 from the atmosphere and sea water by using ecological hydro-technical structures (EHS) for mariculture (marine aquaculture). Under normal conditions, they are overgrown by mussels using the unlimited amounts of Ca and CO2 in seawater to build their shells. Washed ashore by the waves, the shells accumulate into shelly-sandy beaches thus preventing the coastal erosion and the landslides. The EHS solve practically at no cost and simultaneously all the protection and exploitation problems of the coastal zone and shelf, including the absorption of the CO2 acting as “biological pumps”, as the funds are spent only for building and installation of the structures.
Keywords: global warming, carbon dioxide, geoegineering methods, mariculture, ecological hydroengineering structures.
Nikolay Tsekov – THE “AUTHENTIC” RURAL POPULATION AND ITS ALTITUDINAL DISTRIBUTION
The pace of depopulation of villages in Bulgaria is among the highest in the world, and the trend of its acceleration tends to increase in the scope of affected rural communities. Although serious damages that the depopulation causes to the country and its chances for positive demographic, social and economic development, there are not many studies dedicated to the problems and consequences of rural flight and desertification of rural areas. In the paper below represents a new approach for studying of the expansion of depopulation and territorial redistribution of Bulgarian rural population after WWII. The focus is put on the tracking of dynamics of the number of the “authentic” rural population – the population which has always been rural for the period of researching. The changes in altitudinal zonation of that kind of rural population for 1946-2011 has been used as an illustration of the implementation of “authentic” rural population researching approach.
Keywords: “authentic” rural settlements, “authentic” rural population, pace of rural
depopulation, population redistribution, altitudinal zonation.