ISSN 2367-6671 (Online)
PROBLEMS OF GEOGRAPHY
This issue of the “Problems of geography” journal is dedicated to the life and works of prominent Bulgarian geographer prof. Ivan Batakliev, Ph.D.
Tsvetan Kotsev, Velimira Stoyanova, Yanitsa Petkova, Nina Dyakova – Concentration of heavy metals and metalloids in the river sediment of the lower stretches of Vardar, Struma, Mesta and Maritsa rivers close to the Aegean sea
Gergana Metodieva – Bibliographical analysis of the publication activity of prof. Ivan Batakliev
The article discusses 342 scientific works of prof. Ivan Batakliev, which were published and reissued during the period between 1921 and 2013, including 235 papers of the same author (reissued ones included) and 107 papers on prof. Batakliev by other authors (biographical materials, reviews etc). The discussed papers have been sorted on the basis of various criteria such as: number, topic, date of publishing, branch of geography, own or in collaboration with other authors, language in which they were published, regions studied in the papers. The regional orientation of the studies has been presented by contemporary administrative districts and their current areas and by physical-geographical regions of Bulgaria (same principles have been used for papers discussing regions in foreign states). As a result of the performed bibliographic analysis and characterization of the scientific activity of this prominent Bulgarian scientist, a better notion of the specifics of his studies can be obtained – their diverse character, the regions which were most studied etc. The paper titled “Ivan Atanasov Batakliev 1891–1973: Bibliography”, issued by “Nikola Furnadzhiev” Regional Library in the city of Pazardzhik, editor: Rositsa Geneva, has been used as a source of information in the current paper.
Keywords: Work, analysis, bibliographic analysis, publication, periodicals, books
Poli Roukova, Marian Varbanov, Aleksandra Ravnachka – Globalisation impact on information technology services in the European Union in the pre-crisis period
The paper aims to present the impact of globalization on the IT services in the EU countries during the pre-crisis period. The analysis of the economic performance of the sector outlines certain development trends. The position of the EU computer services in the world trade has been examined. The study focuses on the territorial- organizational forms and the division of labour within the EU countries, underlining the intraregional specifics among the new and the old member states. Special atten- tion has been paid to the analysis of the IT services in Bulgaria.
Keywords: globalisation, IT sector, division of labour, territorial organization
Nadezhda Ilieva, Veneta Lobutova – Spatial segregation – nature of the problem, factors, key features
The spatial segregation is manifested differently in the various histor- ical periods, influenced by the complex course of ideological change. Post-socialist societies face lots of challenges that lead to complex structural changes, including in the cities. Contemporary forms of spatial segregation are mainly related to income in- equality and ethnicity. During the 1920s, the Chicago School created the first concep- tual framework of spatial segregation. In Bulgaria the problems of spatial segregation are linked to the formation of neighborhoods of Roma population in big cities. This article examines the nature, patterns and factors, which influence the formation of spatial segregation, as well as the positive and negative effects of this phenomenon. A definition of spatial segregation is proposed. The spatial segregation is multidi- mensional phenomenon of spatial concentration of a group of people with a certain
class, ethnicity and /or race, which is a result of voluntary decisions (internal factors) adopted as a strategy for survival and preservation of their culture and identity, or is a consequence of direct or indirect constraint (external factors), such as a direct or indirect discrimination, economic constraints, social exclusion, institutional policies, etc. Spatial segregation might form from a mix of internal and external factors. The proximity of large number of disadvantaged households aggravates and prolongs the shortcomings of spatial segregation, thus new forms of social interaction, which lead to sustainable economic status and active citizenship should be seek.
Keywords: spatial segregation, internal and external factors factors of spatial segrega- tion, effects of spatial segregation
Vasil Marinov, Petko Evrev, Mariana Assenova, Elka Dogramadjieva – The concept for tourism regionalization of Bulgaria: Theoretical requirements, legislative provisions and practical implications
Tourism regionalization has been a subject of academic debate in Bulgaria since the late 1960s and a lot of theoretical, methodical and practical experience has been acquired in the field of working out tourism regionalization schemes. However, none of these schemes has been officially recognized and despite of the renowned practical necessity of defining up-to-date tourist regions, the elaboration of a new scheme during the past decades has been constantly accompanied by tension and conflicts between the urgent political needs and both the theoretical and methodological challenges of tourism regionalization. The establishment of tourist regions was officially set for the first time in the new Tourism Act in 2013. Implementing the law a Concept for Tourism Regionalization of Bulgaria was developed in 2014 with the participation of the authors of the current paper. The paper presents the core principles and criteria applied in the Concept for Tourism Regionalization of Bulgaria (2014) delineating the country”s nine tourist regions. Emphasis is placed on the pragmatic approach of combining theoretical rationales with legislative provisions concerning the formation of tourist regions for marketing purposes and the establishment of regional destination management organizations. Stressed is the need for finding the point of intersection between the strict academic requirements and compromise practical solutions in defining the tourist regions to achieve both methodologically robust and feasible result acceptable to a wide range of stakeholders.
Keywords: tourism regionalization, requirements, principles, criteria
Maria Grozeva – Main objects of the immovable cultural and historical heritage in the district of Pazardzhik
Pazardzhik district occupies the western part of the South Central Planning Region in Bulgaria (NUTS II). In that capacity it has a crossroad position on the Balkans, which is reflected in its historical and economic development. The oldest found traces of human activities in Pazardzhik region are by the Eneolithic era. This report reviews briefly the major objects of the cultural-historical heritage in the district classifying them according to the historical characteristics, their functionality and their physical size in geographic space.
Keywords: Pazardzhik district, South Central Planning Region, human activities, immovable cultural-historical heritage
Boris Kazakov – Typology of the rural settlements in Southeast Bulgaria according the demographic situation
The article presents an attempt to perform a typological classification of the rural settlements in Southeast Bulgaria (the districts of Burgas, Sliven and Yambol). Based on the analysis of eight demographic indicators selected for that purpos, the method of grades assessment has been applied in order to perform a typological classification of the studied villages, resulting in their division into four types. The method is based on assessing the condition of all 8 indicators used to perform the classification: according to their values in each case (village), grades from 1 to 5 are given for the best and the worst values respectively (the division into 5 intervals is based mainly on the average value of the indicator) and ultimately – a combined grade is calculated for each village as a sum of the grades it has received for each indicator. Finally the whole range of combined grades (varying between 8 and 40) is partitioned into 4 groups (types) on the equal intervals principal, which types represent the demographic situation of the studied villages. The resulting distribution of the studied settlements into four types is as follows: type I (“relatively good demographic situation”) – 18.7 %; type II (“moderate demographic situation”)– 33.1 % of all villages; type III (“deteriorated demographic situation”) – 38.3 % and type IV (“extremely deteriorated demographic situation”) – 10.0 % of the villages in the region.The article is part of the PhD thesis of the author – “Demographic situation of the villages in Southeast Bulgaria “, which is to be completed and defended.
Keywords: demographic situation, typology, grades assessment method, rural settlements
Chavdar Mladenov – Dynamics of the population in the Rhodope mountains – general trends and geodemographic characteristics
Analysis of the current state, trends and spatial characteristics of the population dynamics in the Rhodope Mountains has been made. A stable trend of population decrease has been established since 1992, although with decreasing rates (from –1,32% during the 1985–1992 period, to -0,55% during the 2001–2011 period). The depopulation process has affected most of the Rhodope Mountains territory, while the prevailing types of population decrease are types V and VI. Compared to the recent past, spatial disparities of the population dynamics have diminished. A higher polarization of the population distribution is now visible as compared to previous periods, together with increasing share of the urban population combined with depopulation of large rural areas. Emigration has proved to be the leading depopulation factor during the 1985–2011 period. The current trends in the population dynamics of the Rhodope Mountains predefine further depopulation. There is lack of purposeful regional and demographic policies aiming to oppose the negative trends and to optimize the migration flows while taking into consideration the reproduction capacities of the local population and the available local resources.
Keywords: demographic situation, depopulation, fertility, mortality, population growth, migration balance, type of increase / decrease in the populationр coefficient of depopulation.
Krum Bozhikov – Aging of the population in the Rhodopes
This article reveals specific features in the process of population ag- ing in the Rhodopes. In the situation at the end of the 80″s of the twentieth century, and after the transition to a market economy, many changes occur. They led to the deterioration of the demographic situation in the Rhodopes and very fast pace of population aging. Because of its ethnic composition there are big differences in the area of interest. In some parts of Rhodopes demographic aging process is at much slower pace than the national average, while in others – much bigger. The main factor influencing this process in the Rhodope Mountains is emigration. Birth rates also had a major influence, but less than emigration for the aging. Aging process shows differences in Rhodope inland, as well as in the rest part of the country. Much of the mountainous areas are less or almost not affected by this process. Cases where demo- graphic aging in the Rhodopes have a very strong pace, are exceptional compared to the total mountain territory.
Keywords: aging, Rhodopes, population, mountain territory, birthrate
Aleksandra Ravnachka – Unemployment in Blagoevgrad district: status, trends and regional differences
Regarding the dynamics of the unemployment rate in Blagoevgrad district, two sub-periods can be defined within the whole study period. The first one is between 2001 and 2008 when, as a result of the stabilization of the economy and the labour market, a steady trend of employment growth was detected. The second sub-period started with the emerging of the economic crisis and lasted till the end of 2011. During that period the number of registered unemployed people, as well as the unemployment rate in Blagoevgrad district, significantly increased. Serious spatial disparities in the unemployment rate exist in the district, which are being deepened by the economic and financial crisis in the country as a whole. That negative trend requests the implementation of specific measures for reduction of the regional dis- parities, mostly aiming at bringing investments and thus creating new jobs, as well asat boosting the education level of the population and its vocational training in fields adequate to the local economy needs.
Keywords: Blagoevgrad district, labour market, unemployed, unemployment rate, spatial disparities
Velislava Simeonova – The urban primacy in Latin America (the case of Bogota, Colombia)
This work analyzes aspects related to macrocephaly and urban primacy in Latin America by doing a comparison between such characteristics in different regions and with a special emphasis in the Colombian capital, Bogota, pointing out changes and transformations that are manifested in sociospatial conflicts as a result of neoliberal economic and social policies. The main objective of this research is to analyze how uncontrolled growth is accentuated and evolves due to depend- ence models imposed by the hegemonic power of developed countries. These models are associated with the perverse concentration of productivity, urban demographic growth and the concentration of social issues in the city of Bogota. The methodology used is analytical and descriptive, taking into account different documentary and statistical sources that allowed us to determine some changes in Latin American capitals and the city of Bogota as a specific example of the causes that produce the phenomena associated with economic changes that external agents influence on. The effects of this dynamic can be identified as urban chaos, overpopulation, service deficiencies, urban periphery growth, and environmental conflicts among others. This process allowed us to identify conclusive aspects of today”s situation.
Keywords: urban system, urbanization, Bogota, global city
Yulia Krumova – Contemporary peculiarities and role of cartographic design in thematic mapping
The impact of dynamic computer technologies and applications of cartographic visualization on the development of contemporary thematic cartography raises the question of the place of traditional cartography and cartographic design in the process of map creation. A certain tendency of technologicalization of map pro- duction is delineated, that in some cases leads to decrease in the quality of the final product – the thematic map, as a clearly structured and synthesized bearer of geospatial information. The rapid improvement of geoinformation technologies in that field shows a significant growth in the volume and diversity of cartographic production. Furthermore, the resulting expansion of the range of producers “non- cartographers” leads to the emerging of a certain number of cartographic works, especially in printed publications, deprived of communication and cognitive properties. Although many of those maps are impressive in terms of nature of their contents and have an impres- sive design, the disregard or the ignorance of the fundamental principles and leading cartographic rules and approaches of the graphic construction hamper the orientation and impede the map reading. Among professionals, the skill in mastering specialized software applications has gained priority over the cartographic and graphic culture. In the process of thematic mapping, the cartographic design is oriented primarily towards the clarity of the reader”s perception. The examples given in this work il- lustrate the argumentation in choosing the means of visualization and the leading role of cartographic design in highlighting the semantic peculiarities of the objects in the special thematic content. The specifics of the graphical construction of cartographic works is associated with adoption of the basic linguistic graphic forms and structures of the cartographic symbolization, adequate to the content, the cartographic means, the map scale and the consumer audiences. It is the correct application of all of the above which would ensure the success of the cartographic translation, the clarity and the message purity of the future thematic map.
Keywords: thematic cartography, cartographic design, cartographic symbolization, cartographic means, graphic approaches, graphic contrivance
Emilia Tcherkezova – GIS-based regionalization of geomorphological units in the floodplain of Ogosta river between Gavril Genovo and dam “Ogosta” (NW-Bulgaria)
This paper presents the results of computer-based landform classification of the area between the settlement Gavril Genovo and the “Ogosta” reservoir (NW-Bulgaria). Data obtained from Airborne Laser Scanning using RIEGL LMS-Q680i long-range and RIEGL VQ-820-G hydrographic airborne laser scanner with online waveform process- ing were used for generation of a precise Digital Terrain Model (DTM) 1×1 m. A meth- odological approach was proposed und tested for delineation of landform patterns in the floodplain. It includes delineation and cross-classification of Topographic Classifi- cation Index for lowlands and Vertical Distance to Channel Network in 56 classes using SAGA GIS. In order to achieve more real landform units the result was reclassified in 26 classes and verified through field investigation after a flood event in April 2014. Other compound geomorphometric variables, e.g. SAGA Wetness Index, Multiresolu- tion Index of Valley Bottom Flatness were calculated. The obtained result can be used for detailed geomorphologic field mapping and can be applied in areas with similar geomorphographic and geomorphologic conditions.
Keywords: Digital Terrain Model (DTM), Airborne Laser Scanning Data (ALS), geomor- phology, geomorphometric variables, landforms, geomorphographic units, Ogosta floodplain
Rumen Penin, Dimitar Zhelev – Geochemical research of azonal landscapes in the Starozagorsko pole formed by human impact in the antiquity
A complex landscape research was conducted in the East Upper Thracian Plain (Starozagorsko pole) in the summer of 2012. Particular interest is the observation and the investigation of azonal landscapes whose genesis is related to the human impact in ancient times. The research object is the locality “Tuzlite” near Sarnevo Village, Municipality of Radnevo. That place is representative for many similar landscapes around Thracian tombs in South Bulgaria. The human caused accumulation of land mass around the tombs created negative land forms in the local topography in the past. The high level of ground waters in such places is the major trigger that makes the specific kind of azonal landscapes rich of saline soils (Solonetz type). Representative soil samples have been collected in lateral perspective as well as in radial soil profile. The soils of the neighboring Thracian tombs have been inves- tigated too. In addition, the dominant local halophyte (Puccinallia distant) has been researched in order to be clarified the biogeochemical specifics in the area. The analy- ses have been made in the Geochemistry Laboratory of the Faculty of Geology and Geography, Sofia University “St. Kliment Ohridski”, Bulgaria, applying the method of atom-absorb spectrophotometry with the spectrophotometer “Perkin-Elmer” – AA. The general content of elements Cu, Zn, Pb, Mn, Ni, Co, and Cr has been found. An interpretation of the results applying geochemical spectrums has been made. The ele- ments with well-determined radial differentiation have been outlined and have been explained. The research enables us to draw conclusion for the paleogeographic and paleogeochemical environment in the investigated part of the Upper Thracian Plain. The research results give relatively reliable geochemical “picture” of the area and al- low comparative studies with similar territories in either other parts of Bulgaria or abroad. They could enable the organization of soil and geochemical monitoring in the investigated area.
Keywords: heavy metals, solonets soils, azonal landscapes, halophytes, anthropogenization, ancient
Tsvetan Kotsev, Velimira Stoyanova, Yanitsa Petkova, Nina Dyakova – Concentration of heavy metals and metalloids in the river sediment of the lower stretches of Vardar, Struma, Mesta and Maritsa rivers close to the Aegean sea
The aim of the current reserach is to present an actual and overall picture of the heavy metal contamination of the river channel and floodplain sediment in the lower stretches of the four biggest international rivers which flow into the North of the Aegean Sea. Two sampling campaignes were carried out in 2010 and 2014. Concentrations (ppm) of As, Pb, Cd, Zn, Cu, V, Cr, Co, Ni, Mo, Sn, Sb, Mn, Fe and Al are measured in < 0.063 mm fraction of 28 river sediment samples using XRF spectroscopy. The measurements of heavy metals are performed at the premises of the Soil Chemistry Group to the Institute of Biogeochemistry and Pollutant Dynamics, ETH-Zurich. Vardar River turns out to be the most heavily pol- luted river in the region followed by the Maritsa River, while the Struma and Mesta rivers are determined to be less contaminated. Most of the measured heavy metals and metalloids are found to exceed their average background levels in river chan- nel and floodplain sediment reported in the Geochemical Atlas of Europe. Values of As, Pb and Cr are higher than the TEC threshold of USEPA in all the sampling sites. PEC threshold of USEPA is exceeded by Cr and Ni in nearly the half sediment samples and by Cd and Pb in a few cases. Levels of Cr, Ni and Zn over the Dutch intervention values are found in the Greek section of Vardar and in the Maritsa Delta. Contaminats of the highest concern in the studied stream and floodplain sediment samples from the Vardar River are the following trace elements (number of samples/ aver/min/max, ppm): Cd (7/2.2/1.2/4.3), Cr (7/386/270/497), Ni (7/102/82/151), As (7/20/16/30), Pb (70/59/81), Co (7/22/<14/30), Sb (7/1.8/1.0/3.3), Mo (7/1.5/0.4/3.8) and Cu (7/41/31/57). The main point sources of pollution are located in the former Yugoslav Republic of Macedonia (FYROM), e.g. the Cr mine Radusha and the "Ju- gohrom Ferroalloys" smelter near Jegunovce, Pb-Zn mines near Zletovo, Sasa and Taronica and the Pb-Zn smelter near Veles, the Cu mine near Buchim, the Cr-Sb-As mine Loyane in the North of the country and the Ni mine and smelter near Kavadarci. According to the E-PRTR data, the well developed industry of the city of Thessa- loniki enriches the Vardar sediment with Zn, Cu, Ni, Cr, Pb, Cd and As. Most of the heavy metal pollution sources in the Maritsa River basin are located on Bulgarian territory. Specific contaminants for the lower stretch of the Maritsa River are Cd (10/4.1/2.2/6.8), Sb (10/3.3/2.5/4.4) and Pb (10/100/66/151) sourced by the Pb-Zn mines in the Rhodopy Mountain and by the Pb-Zn smelter near the town of Plovdiv. Loads of Cr (10/135/69/248) and Ni (10/50/30/70) to the Maritsa River system are reported by E-PRTR for the Waste water treatment plant of Plovdiv, the coal power plant "Maritsa Iztok 3" and the textile factories in the towns of Sliven and Yambol. Major sources of Cu (10/65/29/107) and As (10/17/12/30) are the mines in the Sredna Gora mountain and the Cu smelter near the town of Pirdop. Stream and floodplain sediment of the Struma River upstream the Butkovsko (Kerkini) lake and near the river mouth into the Strimonian gulf are enriched mostly in Co (8/34/<7/43) and Mo (8/2.2/<1.2/3.2) considering the European background. Concentrations of As and Sb in the sediment near the river mouth are found to be higher than in the area upstream the Butkovsko lake. Sediment of the Mesta River upstream its delta show the lowest levels of heavy metals compared with the Vardar, Maritsa and Struma riv- ers. Cadmium (3/1.0/0.8/1.2) and antimony (3/2.1/1.9/2.3) exceed nearly three times the European background, while the rest of the microelements fall in the range 1-2.6 times over their natural levels. River sediment quality assessment against the PEC (probable effect concentration) threshold of USEPA determines Cr and Ni to be the most serious threat to the ecosystems realted with the studied rivers. Average values of both elements are 2-3 times over the PEC thresholds in the stream and floodplain sediment of the Vardar and Maritsa rivers and reach 80–90% of the limits in the Struma"s and Mesta"s sediments. The two pollutants exceed also the relevant Dutch intervention values for soil and sediment in the samples from the Vardar Valley and from the Maritsa Delta. The authors would like to thank the Prof. Ruben Kretzsch- mar, Kurt Barmettler and Petar Mandaliev from the IBPD, ETH-Zurich for their help with the XRF analysis of the collected sediment samples.
Keywords: river sediment, heavy metals, arsenic, Vardar, Struma, Mesta, Maritsa, Aegean sea
Borislav Grigorov, Petar Dimitrov, Assen Assenov – Landscape biodiversity of Mala planina mountain
The objective is to identify and analyze the landscape biodiversity in Mala planina. The creation of a landscape map with the application of the classification landscape system LANMAP 2 is also a main target. The study is based on the terrain an d cameral research for verification the landscape biodiversity in Mala planina and the mapping of the habitat types in this area. Geophysical descriptions are made. A certain literature search is also made. The landscape map is created using the classification system LANMAP 2, by the use of a GIS program. The work on the map includes: 1) creating a vector layer of the relief; 2) creating a climatic vector layer; 3) creating a layer of the edaphic component; 4) adding a vector layer of the vegetation; 5) combination of all these layers. The classical genetic approach for systematization and classification helps for achieving better results in this landscape research. This approach helps for the consideration of all possible factors for landscape differentiation (natural and anthropogenic). The characteristics of the watersheds in Mala planina are used. They are natural systems which have functional integrity and fixed boundaries. Mala planina has some unique features of its landscape biodiversity. Mala planina provides vast amount of quality ecosystem/landscape services and one of the best features of this mountain is that it”s very close to the Bulgarian capital.
Keywords: landscape biodiversity, landscape map, vector layer
Petko Bozhkov – Morphometry of the Konska river catchment
The aim of the presented research is to execute a morphometric analy- sis of Konska river catchment. It provides quantitative information for the basin. Selected morphometric parameters extracted from DEM are analyzed – elevation, slope, vertical segmentation (local relief per square km) and horizontal segmenta- tion (total stream length per square km). Topographic sheets are also used for certain measurements. Some linear, areal and relief aspects are discussed through which a general geomorphic and geographic characteristics are developed. The study area in this paper is part of Srednogorie and Kraishte physical geographic regions which location determines the topographic variations. A map of stream orders is created, which shows some characteristics of the drainage network. The analysis has preliminary character as the accomplished results could be used in various surveys.
Keywords: geomorphometry, river catchment, drainage network, GIS
Ivo Velichkov – Characteristic of base flow during low water period in alpine part of the Maritsa river basin
The base flow of the rivers, determine the guaranteed water supply in individual river basins and territories, and its study is a key component in the analysis of the low river water. This report explores the temporal parameters of the flow formed entirely from groundwater in the basin of Maritsa River – elevation 1,400 (the second average altitude river basin in the country). The analysis is based on daily discharges for 33 years, Hydrograph Separation Program and standard statistical meth- ods, and procedures. The base flow of the study period is 1,01 m3/s and varies from 0 m3/s to 16,30 m3/s. It forms entirely quantity of river water for uninterrupted periods continuing from five to 207 days. Most frequently the duration of the base flow is between 8 and 14 days, or two weeks. The base flow forms 100% of the river flow in all months except May, June and July. It is one of the evidence that the hydrological year in the high altitude river basins, differentiate two seasons. The characteristics of basic flow of Maritsa River – elevation 1,400 can be used as analog in unexplored river basins with an altitude above 2000 m.
Keywords: base flow, Maritsa River
Daniela Borisova, Zvezdelina Aydarova, Stefan Stefanov, Neli Hristova – Extreme values of the flow in the Maritza river basin (Pazardjhik) for the period 2000–2005
The еxtreme hydrological values are characterized by changeability, accidental and indefiniteness. This is reason for the different approaches and meth- ods in their research. One of the ways for their identification is based on a certain threshold values. In the present study was analyzed the temporal and probabilistic parameters of the extreme maximum and minimum flow in the river basin of the Maritsa River to the Pazardzhik at the beginning of the XXI century. The study is based on the daily water quantities in ten hydrometric stations (three of the main river and seven of its tributaries) for the periods 2000–2005. The absolute annual maximum values of the river flow in the entire valley were registered in 2005. They vary from
24,2 (Raduil) to 799,4 m³/s (Pazardzhik) for the main river and reached values of 39,2, 150,0 and 284,8 m³/s for the tributaries Yadenica, Chepinska and Topolnica. High waves of the flow are registered in all years and months with the highest in- tensity within the spring hydrological season. They continue from one to three-four months with correlation between small continuance and high intensity. Extreme low flow in a river basin of Maritza arise every year within the summer-autumn hydro- logical season (most of all August and September) and at times in winter. Their dura- tion is up to three months. By hydrological drought the water flow/level is below 1,00 m³/s. Extreme high and low water flow in river basin of Maritza next tо the city of Pazardzhik for the first years of XXI c. are close to those, calculated within the next century. The analysis of the values upgrade the previous studies on the base of a new methodological approach.
Keywords: maximum flow, minimum flow, threshold method, Maritsa river
Simona Lukarska – Characteristics of the extreme waters in the river Arda valley for the period 2000–2005
The extreme flow of the Arda River and its tributaries is one of their most typical hydrologic characteristics. The study marks the boundary values of the outlet for a period of one or more years. The present report analyses the quantitative parameters and the time behavior of the very high- and low-level waters in the valley of Arda river for the period 2000–2005. The study is based on daily data and threshold values as recommended by IHA. During this time, many high-level waters are registered each year in the winter and spring hydrologic periods. Values of the maximum drainage vary from 127 m3/s to 1016 m3/s. High waves, with duration of a week, have the highest frequency. The extremely low-level waters in the river basin are typical for the summer-to-autumn hydrologic season, but not in all of the years of the analysed period. They are characterized by low duration – from 1 to 7 days, and water amounts of 0.05 to 1.3 m3/s. The extreme flow in the Arda River basin has time and quantitative characteristics similar to those registered in the past century. The present study also supplements the hydrologic analysis of drainage values for the Arda River for the rest of the country.
Keywords: low-level waters, extremely low-level waters, Arda river