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Heavy rainfall in the summer have become more frequent, and when they occur over the coastal region, the cumulative hazardous pressure leads to floods, loss of physical life and socio-economic impact. Such is the disaster due to the floods in Tsarevo at the end of summer 2023. The paper contains a conceptual analysis of hydrological and meteorological conditions, land cover and use, and institutional preparedness to deal with dangerous floods. It is prepared on the basis of the data from Copernicus Land Monitoring Service, NCEP Reanalysis, EFAS-EC (European Flood Awareness System), IMERG-NASA (Integrated Multi-Satellite Retrievals for GPM), national hydro-meteorological measurements and CLM model study. The results of the research show that in addition to severe weather conditions, the human factor has contributed to the disaster situation - inadequate information to the population, problems with the dams around Tsarevo, over urbanization, failures in critical infrastructure maintenance, unavailable public information for surface and groundwater monitoring. [ABSTRACT FROM AUTHOR]

Floods are one of the most devastating natural disasters that can lead to significant economic and environmental damage and even loss of lives. Flood hazard mapping is one of the measures of disaster risk reduction and becoming a more important function in conserving biological diversity and protected areas now and future. Most of the research is focused on determining flood risk in urbanized areas. In this paper, the protected areas affected by potential floods are studied. Protected areas are according to a directive Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the conservation of wild birds and Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora. The selected study area is the Batova River catchment. A large part of it is a protected area under both directives and there are recorded a lot of significant floods. The software product HEC-RAS, version 6.0, was used to determine the flooded areas. Flood maps are created for three scenarios: 20-, 100- and 1000-years. The data used to simulate flash floods are precipitation from monitoring network of the National Institute of Meteorology and Hydrology (NIMH), a Digital terrain model with pixel cell 6/6m from Military Geographical Service at the Ministry of Defense of the Republic of Bulgaria and land cover data from CORINE Land Cover 2018. As a result of the modeling, the inundated areas during rain with different return period have been determined. An analysis was made of the extent to which they affect the protected areas. This approach can also be applied to other watersheds. Based on these studies, an appropriate set of measures could be drawn up to protect these areas and the endangered species whose habitats fall within them and contribute to the preparation of Flood Risk Management Plans. By integrating floodplain management and wildlife conservation, such as the protection of habitat communities have the opportunity to reduce flood risk, and protect species and their habitat while enjoying the natural resources. [ABSTRACT FROM AUTHOR]

This paper provides a detailed picture of the existing legislation of agricultural land use by entities who do not own it in Bulgaria and makes specific suggestions to improve it, aiming at creating a legislative framework enhancing productivity and sustainability. The study is briefly considering the historical and economic factors for the development of the case law in line with the legal framework in thiscontext. Attention is also paid to the goals of the European Union (EU) to provide properconditions for technologicalization of agricultural production, investment in irrigation and other equipment, obtaining external financing, alongside with ensuring profitable sale of production. Undisputedly there is a need to strike a balance between the interests of private land owners and the broader public, by creating a legal basis (through legal and administrative measures) governing the actual use and cultivation of agricultural land. The paper further examines and discusses a number of on-going issues, i.e. the legal status of existing agricultural cooperatives; the consolidation of agricultural land by creating land use plots;the so called "white spots" of undeclared land; the options of leasehold versus renting of agricultural landand its legal framework. The conclusion contains a general analysis of the proposals for changes in the regulatory environmentin the observed area to achieve more efficient and sustainable use of agricultural land. The contribution of the report is to show the variety of models of land use in agriculture and their differences, analyzing the actual legal framework and giving concrete proposals for improving it. Comparative method, synthesis and analysis are used while inspecting the area of research. [ABSTRACT FROM AUTHOR]

Future climate scenarios of the Global Circulation model (GCM) show an increased frequency of heavy rainfall events, which may lead to more severe floods. It is also expected that more and more areas will suffer due to flooding as a result of growing urbanization. Public attention has increased in many parts of the world in recent years and calls have been made to improve flood warnings, including the United States, the European Union and Australia (Hapuarachchi, H.A.P, and Q.J. Wang 2008). To respond and manage flood hazard there is a need to provide a high spatial resolution flood forecast and with sufficient lead time. This study presents an approach for creation of a forecast model based on the analysis of historical hydrometeorological data from conventional and automatic monitoring networks of the National Institute of Meteorology and Hydrology in Bulgaria. The study area is the downstream Kamchia river watershed. Real-time water level observations and calculated discharges based on temporary rating curves are used to dynamically adjust the runoff forecasting. In this paper an approach for combining a hydrological model (TOPKAPI) and a twodimensional hydraulic model (HEC-RAS) for flood simulation is presented. Hydrological modelling is used for forecasting the outflow at a hydrometric station (43800) on Kamchia River near the village of Grozdyovo. The 2D hydraulic HEC-RAS model is used for simulating rainfall - runoff process in Kamchia watershed downstream of the village of Grozdyovo and the results from the hydrological modeling are used as an input data. In this paper the results of using operational hydrological data and forecast precipitation totals for flood simulation is presented. [ABSTRACT FROM AUTHOR]

To maintain enough water in the river for ecosystems protection and river bed sanitation, water have to be allocated to ecosystems, as it is allocated to other users like domestic use and industry, agriculture and power generation. Water distribution is critical in dry periods. This requires proper determination of environmental flow (river ecosystem minimum permissible flow) by hydrology-based assessment methods. The purpose of this paper is to compare selected hydrological methods and to define the scientifically acceptable way to determine environmental flow within a section after the dam of some reservoirs in Bulgaria. As well as some critical reaches of the river network are determined where the necessary living environment for water communities is not provided. Here environmental flow is calculated using conventional hydrological methods: flow duration curve, the Q10% (average multiannual discharge) method and Q95% (yearly minimum monthly mean discharge with a 95% probability of occurrence) method, which are highlighted according to Bulgarian Water Law. In conclusion, the Q10% and Q95% methods allow obtaining environmental flow regimes on a monthly basis capable of adapting to the hydrological variability of the natural regime. The requirements and methods presented in the paper can be applied in the water management legislative process. [ABSTRACT FROM AUTHOR]

Security planning and disaster management are critical areas of focus in Bulgaria, given the country's vulnerability to various natural and man-made disasters, including earthquakes. Bulgaria has established an emergency management system for disaster preparedness, response, and recovery. This system includes various government agencies, non-governmental organizations, and volunteers who work together to ensure an effective response to disasters. The Bulgarian government and the science community conduct risk assessments to identify potential earthquake hazard zones and to assess the risks they pose to people and infrastructure. Bulgaria actively participates in international cooperation efforts related to disaster management as those of the European Union's Civil Protection Mechanism and the United Nations Office for Disaster Risk Reduction. Several projects have been implemented funded by the European Commission as the SHARE project, which aimed to provide a community-based seismic hazard model for the Euro-Mediterranean region, and DACEA and ESNET projects aimed to develop a seismic hazard and risk assessment for the Balkan region, and mechanisms for early warning, public awareness, and quick response in case of a disaster. The present paper gives an overview of the country's focus on risk assessment, disaster preparedness, response, recovery efforts, and international cooperation, underscoring its commitment to disaster management. The topic is particularly relevant now because of the severe consequences of Turkey's recent strong earthquakes. We present findings from various international cooperation efforts in Bulgaria related to earthquake disaster management and results from research related to the assessment of seismic hazards and risk in particular regions in the country. [ABSTRACT FROM AUTHOR]

Marine litter is a significant and growing environmental problem with global implications, affecting oceans and seas. This study analyzes marine litter's composition and density, specifically at Kamchiya-Shkorpilovtsi, the longest beach on the Bulgarian Black Sea coast. The monitoring period from 2018 to 2022 covers an area of 7645 m2. To effectively study the area, it was divided into four monitoring transects: Kamchiya-Mouth, Kamchiya-South (Novo Oryahovo Beach), Shkorpilovtsi, and Shkorpilovtsi-South. During the study, a DJI Phantom RTK was utilized to create a high-resolution raster orthomosaic, aiding in identifying marine litter (ML). A total of 8892 items were identified and classified into eight categories: "Artificial polymer materials" (81.94% of total items), "Rubber" (0.74%), "Cloth/Textile" (0.72%), "Paper/Cardboard" (8.37%), "Processed wood" (1.79%), "Metal" (2.87%), "Glass/Ceramics" (3.19%), and "Unidentified" (0.38%). The density of litter was estimated to be 0.24 items per square meter. In terms of abundance, the highest count of ML was recorded in 2021, with 3250 items, which coincided with the pandemic situation in Bulgaria. Throughout the monitoring period, artificial polymer materials constituted the majority, accounting for 82% of the litter. The most prevalent types of marine beach litter were cigarette butts, plastic and polystyrene fragments, industrial packaging, plastic cups and rings, as well as beach-related cosmetic bottles and containers like sunblocks, nets, and net pieces. The cleanliness of Kamchiya-Shkorpilovtsi Beach was assessed using the Clean Coast Index, which classified it as "Clean" with a score of 4.77. Additionally, this study introduced the Plastic Abundance Index (PAI) as a comprehensive measure to evaluate pollution caused by marine debris. The results of the PAI analysis yielded a value of 1.49, classifying Kamchiya-Shkorpilovtsi beach as falling into the "Moderate" type in terms of the number of plastic items in sampling units. This indicates a significant presence of plastics in the beach environment. [ABSTRACT FROM AUTHOR]

The main goal of the analysis presented in the paper is to contribute to a clearer understanding of climate changes in Bulgaria, assessing the long-term changes in annual characteristics of surface temperature and precipitation in the period 1961-2020 and providing climate projections to the end of the 21st century. During the last decades of the 20th century, a tendency towards warming occurred in Bulgaria. Since the 1990s, only four years have had negative temperature anomalies compared to the reference period 1961-1990. Changes in the precipitation regime are also apparent, with increasing frequency of days with both torrential rainfall and dry, hot weather. The analysis of future climate is focused on the projected changes under the four RCP climate change scenarios for selected ETCCDI climate indices, computed on a yearly basis: absolute maximum temperature (TXx), absolute minimum temperature (TNn), the maximum number of consecutive frost days (CFD), the maximum number of consecutive summer days (CSU), precipitation sum (RR), number of heavy precipitation days (RR10mm) and maximum number of consecutive dry days (CDD). The projected significant warming is manifested in the spatial patterns and temporal evolution of all considered temperature indicators. Despite the predicted decreasing precipitation trend, especially in Southeast Bulgaria, the changes are statistically significant only for scenario RCP8.5. [ABSTRACT FROM AUTHOR]

Floods are one of the most devastating hazardous events often causing destruction of infrastructure and loss of lives. In order to mitigate negative flood impact a reliable hydrological forecast is of great importance. Thus using trustworthy information on the meteorological elements that mostly contribute to the occurrence of floods - precipitation and temperatures, is essential. Although the accuracy of the global forecasting models like ECMWF, GFS etc. has improved a lot, still sometimes there are extreme meteorological events not well forecasted or even missed. Given these cases hydrological forecasts also show to be ineffective with not having well forecasted certain events neither having warnings issued. That is why it is important to have robust meteorological analysis and reanalysis data using any available information from stations, radars, satellites, etc. An assessment of the results of modelling the hydrological processes in a watershed using Copernicus' ERA5 climate reanalysis data is presented in this paper. MIKE 11-NAM hydrological module for rainfall-runoff modelling was applied over Fakiyska river basin in Bulgaria and two meteorological datasets (dry temperature at 2 m and precipitation) for the period 2017-2022 were used: one with observed data and the other one with Copernicus' ERA5 climate reanalysis. As a first iteration the hydrological model was applied using observed meteorological data and was further calibrated and validated towards measured discharge data. Next the hydrological processes in the watershed were simulated again using meteorological information for the same period from ERA5 climate reanalysis data. An analysis of the observed meteorological data and the ERA5 dataset was performed prior to comparing the results of the hydrological modelling with the ERA5 dataset to the results of the modelling with observed data. Finally the results of both the scenarios were analyzed for evaluating model performance using ERA5 dataset. [ABSTRACT FROM AUTHOR]

The results of many research projects and studies report that landuse/landcover change (LULCC) is a major driver of the changes in the hydrological processes within a watershed. Landuse induced landcover changes, e.g., urbanization, deforestation, have a direct impact on the hydrological regime of watersheds thus increasing their vulnerability to extreme hydrological events. In this research the Soil and Water Assessment Tool (SWAT) was used to study the landuse/landcover change impact on the hydrological dynamics within a watershed with respect to peak flow. The physically-based, semi-distributed hydrological SWAT model was applied over Vit river basin in Bulgaria. SWAT was set up with a meteorological information for the period 2015-2020 and the Corine Land Cover (CLC2012) dataset was used to classify the different landuse types in the watershed. The model was further calibrated and validated towards measured discharge data. The rainfall-runoff process in Vit river basin was re-modelled by having the calibrated SWAT model applied using the same meteorological input time series data and a future landcover change scenario. Future landuse/landcover change scenario was selected following the "Sustainable Futures for Europe's Heritage in Cultural Landscapes" project (HERCULES) open mapping platform. The results of the simulations with the CLC2012 and the future landcover shange scenario landuse datasets are presented in this paper. The future landcover change scenario simulated daily discharges were compared against the simulated with the CLC2012 dataset daily discharges. The results of the modelled surface runoff with the two landcover scenarios were also analyzed to evaluate quantitative and spatial distribution changes. Compared to CLC2012, the FLC scenario simulation results showed a tendency toward maximal peak flow increase, higher surface runoff and decrease of minimal streamflow. [ABSTRACT FROM AUTHOR]

According to the Bulgarian legislation, the boundaries of the specialized objects of the Black Sea coast - sea beaches, coastal and coastal protection systems and facilities, coastal lakes, lagoons, limanas and wetlands, as well as sand dunes are determined by direct geodetic measurements and are reflected in the cadastral map and the property register, i.e. specialized maps and a specialized register shall be drawn up in accordance with a by-law (ordinance) on the conditions and procedure for the commissioning, creation and maintenance of the latter. The aim of this paper is to present the UML Use Case Model in order to standardize the geodetic activities in the production of specialized maps, register and information system of the above mentioned specialized objects of the Black Sea coast. The created UML Use Case Model contains the necessary Use Case diagrams that: align the definitions and ways of delimitation; the obligations of the administrative bodies to perform actions and to provide information and data; the content, creation and acceptance of the specialized maps and registers; the procedures and conditions for maintaining and updating the specialized maps and registers in a current state and for providing services from them. [ABSTRACT FROM AUTHOR]

Scientific research using advanced observation technologies and mathematical models aimed at estimating seasonal snow cover and its water equivalent (SWE) helps to reduce the costs of snow cover monitoring and improve the management of the soil-water-crop system. Following the above goals, this paper analyzes two approaches - the Community Land Model (CLM) producing own calculated data, and the ESA GlobSnow v.3.0 product based on the European Space Agency (ESA) GlobSnow project satellite data. The studies were carried out in the period 2016-2020 for the Sought Central Region of Bulgaria. The results indicate a significant reduction of snow. The SWE results of the CLM model (covering the whole study area) are compatible with the SWE data produced by the GlobSnow product, which is easy for use, but applicable only for non-mountainous areas. [ABSTRACT FROM AUTHOR]

The Cultural Heritage Act regulates the preservation and protection of the cultural heritage of the Republic of Bulgaria, and the State ensures the protection of cultural heritage regardless of its location. The procedure for identifying, declaring and granting the status of sites as immovable cultural property, as well as the procedure for establishing temporary protection regimes for declared immovable cultural heritage sites and for the protection regimes for immovable cultural property, are also laid down in subordinate legislation. The geodetic production, i.e. land surveying, photogrammetric and remote sensing methods, technologies and solutions, plays a key role in the implementation of the Cultural Heritage Act and the related subordinate legislation with regard to the regimes for the protection of immovable cultural heritage sites and immovable cultural property. The paper presents an innovative approach for systematic solution of specific topical problems related to the conservation of immovable cultural property and immovable cultural heritage sites on the territory of Bulgaria in accordance with the current regulations in the field of Geodesy, Cartography, Cadastre and Spatial planning. Basically, this approach solves the main use cases related to cultural heritage from the point of view of the geodetic production and the persons legally qualified to carry out cadastral and engineering investment design activities, i.e. the graduated surveyors, aka Geodesy engineers. The approach is implemented through Autodesk's concept of direct access and management of spatial data and information, i.e. the application of a file-based industry model in the documentation and modelling of Bulgaria's immovable cultural heritage for its preservation and protection. The implemented file-based industry model applies the Autodesk client-server architecture for: access spatial data using Feature Data Objects technology, edit spatial data, manage Geo-information systems with Industry Models. [ABSTRACT FROM AUTHOR]

The present paper aims to mark the current status of knowledge regarding the area of the Town of Sozopol (ancient Apollonia Pontica) and its future research. The combination of geological and geomorphological data with the acquired archaeological and historical information can restore the ancient landscape of the study area. The research is focused on the landscape of Sozopol and its surroundings, due to it being among the most important areas in the history of the Western Black Sea. A mechanism for the formation of the tombola between the Skamni Peninsula and the mainland is proposed, as well as a relative dating of its formation. All of this is the result of the successful use of geological, geomorphological and archaeological information, taking into account the age of archaeological sites. Multidisciplinary investigation of ancient archaeological sites is a key research field for systematic investigation. The research used a number of methods characteristic of the Earth sciences as well as the humanities. The knowledge with regards to the evolution of the historical topography of Apollonia Pontica as well as the main features of the ancient environment of the city and its surroundings, is still limited. The article offers options for future scientific perspectives for more detailed and precise restoration of the archaeological landscapes in the study area. [ABSTRACT FROM AUTHOR]

In Bulgaria, the number of water sources and facilities for drinking and domestic water supply from surface and underground water is about 7,480. They are surrounded by sanitary protection zones (SPZ). Each SPZ has 3 belts, which are organised according to an accepted methodology. With the help of a designed geographic information system, it was found that in Bulgaria forest territories that belong to SPZ around water sources and water supply facilities for drinking and domestic needs have a total area of 576,117 ha and 49.837 million cubic meters of total growing stock. The importance of sanitary protection zones for water protection, health and life quality of the population is indisputable. Due to this the goal of the present paper is to systemize forests around water sources with protection functions in Bulgaria in homogenous groups. The systematization is done on the basis of K-means cluster analysis, which is applied for coniferous, coppice and high-stem forests for each of the three SPZ in 28 regions from level NUTS-3 in Bulgaria and three variables, which characterize forests, namely - forest area (ha), mean annual increment (m³/ha), total growing stock of forest territories (m³). On this ground it has been established that high-stem, coniferous and coppice forests from the three SPZ can be systemized in 6, 6 and 7 homogenous clusters respectively. The variables, which contribute to a high extent for cluster formation, are as follows: area of high-stem forests from belt 3; area of coniferous forests from belt 2; and area of coppice forests from belt 3. [ABSTRACT FROM AUTHOR]

Bulgarian forests are part of the national wealth and national identity. Their economic, social and ecological functions are important for the sustainable development of society and for improvement of living conditions especially in rural and mountainous regions. To a large extent these functions are irreplaceable not only in a national but also in a global aspect. In this connection in the present paper a structural-functional characterization of Bulgarian forest territories is done. Actual data on the area of forests, wood stock, wood increment and distribution of forests by functions are presented. Regarding the last one, the attention is focused on concise characteristics of forests with water protection functions on the territory of Bulgaria and water resources of the country. On the basis of the above, the guiding hypothesis for the study is formulated, namely: there is a correlation between the area of forest territories in Bulgaria and the territory occupied by water and water bodies. The verification is carried out by means of a correlation analysis, which is based on data from the National Statistical Institute (NSI) on the areas of forest territories and territories occupied by water and water bodies in 23 districts from level NUTS-3 in Bulgaria in 2021. Regarding the area occupied by water and water bodies, it should be clarified that according to NSI it includes plots for watercourses, water bodies and available water facilities. [ABSTRACT FROM AUTHOR]

The paper analyzes normal corrections for the determination of the normal height differences along the First Order Levelling lines in Bulgaria. Normal corrections are calculated in two ways – with measured gravity accelerations and with gravity data from Global Geopotential Models (GGM). The study uses the last contemporary GGMs developed up to 2160-2190 degree and ultra-high resolution GGMPlus model. Calculations for Bouguer anomalies are made by the calculation service in the International Centre for Global Earth Models (ICGEM). The method for determination of the interpolated values of the gravity anomalies is based on that considered in [15] for all GGMs, with the exception of the interpolated data from GGMPlus. Gravity anomalies from GGMPlus are calculated by using known and modelled data for the height anomalies. In particular, the paper studies the accumulation of systematic errors along the levelling line due to modelled gravity data. Systematic and random error in the differences between the modelled and measured normal corrections are calculated by the Lallemand’s formulas. Although the main part of the value of the gravity anomaly is formed by the development up to degree 2160, the contribution of the omission part of the development can have a significant impact in the conditions of anomalous gravitational fields and in mountain areas. Calculated systematic and random errors are negligible in a smooth gravity field. Application of the present GGM data for each separate levelling distance is possible only for flat areas with a weak anomaly field. The determination of geopotential numbers and geopotential differences can be performed in two ways leading to identical results. The first is the classic one – by using the reduced gravity acceleration values and measured levelling differences. The second one is direct – by using the direct relationship between geopotential differences and normal height differences. [ABSTRACT FROM AUTHOR]

Present paper is a brief story about Bulgarian efforts to integrate data, products and services in Bulgaria into a newly established scientific infrastructure named a National Geoinfomation Center (NGIC) and its efforts to assess and communicate the information about natural hazards and risks to the general public. We started two years ago with the ambitious goal of uniting our observations and research in the area of monitoring and investigation of the Earth’s interior and the near-Earth space. The instrumental units include unique facilities, such as seismic, accelerometric, geodetic, meteorological and oceanographic stations, scientific equipment in several laboratories (geotechnical, paleo magnetic, chemical, biological) and computer systems for innovative calculations and data processing. We have many users, which are research organizations and universities, national and regional authorities, and of course the general public. We are developing a national portal with nice, easy and highly informative plots of different parameters starting from earthquakes, pollution and many others (www.ngic.bg). But, we realized that we must be proactive and to push public to learn about natural hazards and to be more demanding of themselves and the surrounding world. The territory of Bulgaria is located in an area with high seismicity and quite reasonably this is one of the major natural hazards threatening the population and the economy. Monitoring the Earth's environment, including the impact of the Sun on life on Earth affects people through the magnetic field and UV radiation and as is known air quality has become an important issue of people's lives, especially in big cities. In this paper are described data production and service development for earthquakes, UV radiation, geomagnetic disturbances and air quality provided by the National Geoinformation center. [ABSTRACT FROM AUTHOR]

Development of environmental education becomes a topical issue of educational policy and secondary school in Bulgaria. The efforts are mainly focused on integrating and promoting environmentally friendly activities for children indifferent age groups.The paper explores new approaches to stimulate motivation and extension of activities related to sustainable development and environmental protection;new methodologies with a similar focus are interpreted, and specific models for implementation are proposed.The paper offers a general description of Maria Montessori's methodology in the context of environmental education.The author studies the possibilities of geography training for the implementation of environmental education among students.It is considered that using certain notions of Montessori methodology will not only enrich the practice but will increase substantially the engagement and responsibility of every child. The current paper emphasizes the following important aspects:•How children connect with nature•The positive impact of the Montessori teaching method on the child in order to develop respect and caring attitude for the environment•To offer new methods and activities in training process with children in order to achieve environmental protection•To create interactive outdoor spaces for children•To increase the civic engagement of children and improve their ecological literacy [ABSTRACT FROM AUTHOR]

The idea of sustainable land use constantly develops. The technical level of agricultural machinery is constantly improving. The latter is a part of modern technology in agriculture that has an impact on soil fertility and land quality. Soil quality depends on the integrated impact of topography, land use method, and the agricultural practices applied. The wind and water erosion and the other soil degradation processes caused by man's physical interference are due to the chaotic land use and improper dispositioning pattern of the processed areas. The Agrarian Reform in Bulgaria created preconditions for erosional hazardous land use. The state still doesn’t take any serious legal and practical measures against soil erosion and secondary soil compaction. The adequate management of the agricultural land that sets conditions for soil-friendly and economically efficient processing of land, and the rational use of the agricultural machinery, that increases land capability and its value, needs scientifically based guidelines for physical land planning. The objective of the paper is to recommend technical rules for agricultural land design in different topography and land-use conditions. The presented rules are compliant with modern technology in agricultural mechanization and envisage some activities that aim at sustainable land use and sustainable intensification of agricultural production. Terrain measurements and research on agricultural machinery movement in the fields were conducted. The paper recommends dimensional standards for the land planning elements of the arable land, including the agricultural roads in different soil-topographic conditions. It recommends completing the legal framework with texts for agricultural territory physical planning on farm level. [ABSTRACT FROM AUTHOR]

The paper presents our findings during the adoption of e-learning in the National Geoinformation Center of Bulgaria (NGIC). It details the approach used to build a set of functionalities that produce and deliver online educational products to the customers of NGIC. The Center is a consortium of the national providers of Earth observation data with a purpose to design and co-develop integrated information products. NGIC's information system is being developed since 2019. It is built adopting the IT service management practices of ITIL 4 and implementing an original service-microservice architecture. Three dimensions of the proposed solution of the problem – business, technological, and technical are presented. The business process of integrated educational product (IEP) development in NGIC is specified and described within two BPMN models – from the idea for a particular IEP, through its review process by NGIC management to provisioning with resources, actual production, and deployment to the customers as an online or product with blended nature. Two services that support the implementation of the processes in NGIC are detailed – the Authoring service and the Public online education service. The service relationship management and the blending in the architecture of the Center are reviewed. Various specifics of the system engineering and the software modules integration in the system of NGIC are explained. The paper concludes with a discussion over some opportunities provided by that implementation of the service approach – such as ease of employment of a third-party expert domain knowledge and the resources of the virtual community. [ABSTRACT FROM AUTHOR]

The Southern Dobrogea is situated in SE Romania, being included, tectonic point of view, in the Moesian Platform. The Southern Romania is bordered by the Danube to the West and the Black Sea to the East. In the N, the Southern Dobrogea is bordered by the Capidava-Ovidiu subcrustal fault; towards south, it continues to the northern Bulgaria. In the Southern Dobrogea, a carbonate platform developed from Mesozoic (Upper Jurassic and Cretaceous), and continued through the Paleogene up to the Miocene. The Pliocene is mainly developed along the right side of the Danube, in low topographic areas, and is represented by the sedimentation of continental red clay successions. The Pleistocene is characterized by the sedimentation of continental red clays and the development of the loess deposits. This paper describes several protected geological and paleontological sites of the Southern Dobrogea. Some of them, i.e., ‘The Cernavodă Fossil Site’, contain a rich Early Cretaceous macro- and microfaunas, along with ‘The Limestone walls from PetroÅŸani’, exposing Upper Cretaceous and Middle Miocene rocks, and ‘CredinÅ£a Quarry’, enclosing rich faunas of Miocene mammals and mollusks, are protected areas of national interest. Other sites, significant for their geological exposures and paleontological context, are not yet protected, although their geoheritage is of an outstanding importance. The Southern Dobrogea is situated in SE Romania, being included, tectonic point of view, in the Moesian Platform. The Southern Romania is bordered by the Danube to the West and the Black Sea to the East. In the N, the Southern Dobrogea is bordered by the Capidava-Ovidiu subcrustal fault; towards south, it continues to the northern Bulgaria. In the Southern Dobrogea, a carbonate platform developed from Mesozoic (Upper Jurassic and Cretaceous), and continued through the Paleogene up to the Miocene. The Pliocene is mainly developed along the right side of the Danube, in low topographic areas, and is represented by the sedimentation of continental red clay successions. The Pleistocene is characterized by the sedimentation of continental red clays and the development of the loess deposits. This paper describes several protected geological and paleontological sites of the Southern Dobrogea. Some of them, i.e., ‘The Cernavodă Fossil Site’, contain a rich Early Cretaceous macro- and microfaunas, along with ‘The Limestone walls from Petroşani’, exposing Upper Cretaceous and Middle Miocene rocks, and ‘Credinţa Quarry’, enclosing rich faunas of Miocene mammals and mollusks, are protected areas of national interest. Other sites, significant for their geological exposures and paleontological context, are not yet protected, although their geoheritage is of an outstanding importance. [ABSTRACT FROM AUTHOR]

The paper deals with statistical analyses of data on soil properties of Pellic Vertisols selected from the eastern as well western part of the Upper Thracian Lowland, in Southern Bulgaria. Based on the survey in 2019, 2020 and 2021 at conventional and organic farming the data was processed using the statistical package Statgraphics (Anova). Soil textural class was the same a light to heavy clay and the total porosity was low. Natural variability of soils was due to imposed local separateness of organic farming from conventional. None of the studied soil parameters have statistically significant difference by the depth of sampling. Mean pH(H2O) value varied per year of survey, which could be due to a different factors. Available forms of nutrients N, P and K have varied with statistically significant difference per year of survey also. Generally the mean pH(H2O) values were higher at conventional farming nearby Chirpan town. Positive trend was increasing of pH(H2O) in organic farming. The humus content was not affected by the farming system. Negative trend was decreasing of humus content over the years. The mean values on available phosphorus P2O5 and potassium K2O were higher at conventional farming; the available forms of mineral nitrogen were commensurate. The statistical processing of data showed that there was no statistically significant difference of main soil parameters in Pellic Vertisols under conventional and organic farming nearby Karnobat town. [ABSTRACT FROM AUTHOR]

The paper deals with soil properties characterized the intrinsic peculiarity of studied Chromic Cambisols from the Upper Thracian Lowland, in the Southern Bulgaria. To fulfill the aim, a systematic survey and sampling have been carried out on the terrain with conventional and organic systems of farming. Soil physical, chemical and physicochemical properties were discussed including the analyzed data for particle size distribution, content and composition of organic substances, cation exchange capacity, soil bulk density, soil particle density and porosity. The organic matter was directly dependent on the local environmental conditions, the result of natural bioactivity. Soil adsorbent was affected by acidification in the surface horizon so there was evidence of initial destructive processes of the soil adsorption complex, despite the relatively high degree of soil saturation with bases. The comparison between conventional and organic farming showed that there was no statistically significant difference in the studied soil indexes, that could be provoked by the farming system applied at the trials. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to clarify the formation mechanism of the devastating flood in the town of Svilengrad, in the Republic of Bulgaria, in June 2012. The systemic approach is used to analyze flood formation mechanisms and improve under-standing of the complex interactions between the factors determining the formation and manifestation of floods. The spatial analysis method takes a central place in the examination of the flood formation mechanisms, using GIS as a tool for analysis. Hydraulic model for the 9 km long river section has been adapted and for this purpose a Digital Elevation Model (DEM) has been generated. Taking into account the specifics of the riverbed and the results of previous research on the design and investment process in the river area, a one-dimensional model is applied (Hydrologic Engineering Center - River Analysis System, version 5.0.3, developed by the US Corps of Military Engineers) to determine the flooded areas during the flood. The main result of the study is the clarified flood formation mechanism in the town of Svilengrad, which occurred on 06.02.2012. Information on the flood formation mechanism is of particular importance for the institutions responsible for flood risk assessment and management. It will allow them to formulate adequate measures for reduction of the floods risk in this part of the Maritsa River. The popularization of the results of the survey among the population of Svilengrad is a prerequisite for raising its awareness and preparedness for a more adequate response in case of a new disaster/flood. [ABSTRACT FROM AUTHOR]

Flash floods are defined as rapidly developing extreme events caused by heavy or excessive amounts of rainfall. Flash floods usually occur over a relatively small area within six hours or less of the extreme event with quite a rapid streamflow rise and fall. Increased occurrence of flash flood events is expected due to climate change and increase in extreme precipitation events. Flash flood forecasting is still a challenge for hydrologists and water professionals due to the complex nature of the event itself. Besides having sufficient background in hydrological and meteorological forecasting as well as information about local conditions yet an adequate approach for flash flood forecasting is needed. The Flash Flood Guidance System (FFGS) is widely recognized for enhancing the capacity to issue timely and accurate flash flood warnings by providing hydrological and meteorological forecasters with real-time information and products. FFGS is based on global data as well as national hydrometeorological data and analyses. In this paper the use of the Black Sea Middle East Flash Flood Guidance System (BSMEFFGS) products for flash flood forecasting by the hydrologists at the Hydrological Forecasting department at the National Institute of Meteorology and Hydrology (NIMH) in Bulgaria is presented. An overview of the FFGS for Bulgaria with closer attention paid to the Flash Flood Guidance (FFG), Flash Flood Risk (FFR) and the Flash Flood Threat Products is introduced. Two case studies are also presented - a flash flood in the town of Shumen and another one in the area of the village of Popovitsa on September 28th 2015. [ABSTRACT FROM AUTHOR]

Floods are the most frequent and widespread natural disasters worldwide (WMO, 2013). In 2006 for instance, exceptionally high river levels caused loss of lives and considerable economic losses in Serbia, Bulgaria and Romania. Thus risk prevention strategies were reconsidered and the need for common solutions for the Danubian countries was outlined. Non-structural measures to mitigate flood risk as is the improvement of forecasting capabilities on a basin-wide scale are known to be highly effective. The DAREFFORT project is a horizontal initiative to implement a flood risk mitigation measure in a joint and sustainable way on catchment level. The main output was the Danube Region Enhanced Flood Forecasting Cooperation that was a step towards creating the basis of ICPDR Danube Hydrologic Information System (HIS). This was only reached through a standardized data format utilized by the responsible national organizations and improved data exchange between the participating countries as reliable and comprehensive hydrologic data is the basis of sound forecasting in any country. In this paper the Bulgarian experience and contribution to the DAREFFORT project is presented. This study is aimed at overviewing the present status of the national forecasting capabilities and main topics are the process of the hydrological forecasting, data flow, data processing and data exchange. [ABSTRACT FROM AUTHOR]

LiDAR technology expands the possibilities for forest inventory using aerial and terrestrial scanning. A technological scheme for terrestrial personal laser scanning (PLS) has been developed in order to extract numerical tree parameters. The aim of the paper is to determine the characteristics of individual trees and average taxation indicators of forest stands via terrestrial PLS method. The PLS system includes Sensor Ouster OS1-16, mounted on a folding monopod and mini PC for control and recording of primary raw data, the base of creation of the 3D cloud of points. Google Cartographer is a system that provides simultaneous localization and 2D and 3D mapping. Cloud 3D model of the forest area was created by SLAM algorithm (Simultaneous Localization and Mapping). The result from SLAM is a 3D point cloud model in local coordinate system, which is transformed to WGS 84 (UTM 35N) coordinates via GPS data captured with LiDAR and IMU data. The 3D model is additionally processed by specialized application software Cloud Compare, LiDAR 360 and 3D Forest. An integrated algorithm is implemented through the software 3D Forest for segmentation of individual trees and determine their dendrometric parameters-height, diameter of the stem at breast height (DBH), structural data for the crown (diameter, length, height, area, volume), stem volume, and other. Study sites are forest stands on the territory of the South-Eastern Forest Enterprise (Sliven, Bulgaria). The sample plots are selected in accordance with the normative requirements for inventory and planning in forest territories of Bulgaria. The strip sampling method is based on a percentage system - limited proportion of the area is measured, on the assumption that the samples are typical of the entire stand. The obtained results for the individual trees are compared with the data from the parallel performed conventional field measurements at the sites. The differences between the measured by field methods and the PLS method tree height and stem diameter DBH of an individual trees and average data of a forest stands are within the normatively permissible limits in the forestry. Application of the PLS method combined with the SLAM algorithm provides the process of forest inventory and with the ability for fast, objective, and accurate measurement of individual trees and forest stands. The PLS method is a new reliable technological approach for 3D forest inventory and study of forest areas. Created 3D cloud models of forest stands are a qualitatively new type of objective data, which is a step towards to the future and creating of a new forestry database in Bulgaria. [ABSTRACT FROM AUTHOR]

Magnetospheric pulsations and the mechanisms underlying their generation are topics under active studies. The Pc5 (f =1.7-6.7 mHz) geomagnetic continuous pulsations, recorded at mid latitudes (L =1.6) during December 2019, with a low level of geomagnetic activity, are analyzed and discussed in this paper. The data sets of the series on geomagnetic field variations recorded at Panagjuriste Geomagnetic Observatory in Bulgaria are analyzed. The spectral characteristics of the pulsations were determined by Continuous Wavelet Analysis (CWT). It is demonstrated that Pc5 pulsation activity appears with all ranges of periods (140-600s) on December 6, 8, and 18, 2019, at time intervals of 02-17 UTC, 14-20 UTC, and 00-16 UTC, respectively. Then, the solar wind (SW) plasma speed, the flow dynamic pressure, and the geomagnetic index Kp are computed for every case of recorded Pc5 pulsations. It is suggested that recorded continuous pulsations in the Pc5 range are due to step-like or sudden increases in solar wind oscillations and variations of the flow dynamic pressure, which precede the appearance of pulsations and drive compressional magnetic field variations in the magnetosphere. [ABSTRACT FROM AUTHOR]

Nowadays, due to environmental pollution, finding and using alternative sources of energy is a priority for any economy. For this purpose, scholars from all over the world are focusing on finding the best alternative sources of energy. One example is the wave energy. This natural source is characterized by being renewable, inexhaustible, not polluting, thus is not contributing to global warming by generating emissions. Yet such a resource is extremely variable. The aim of this paper is to analyze the Black Sea wave pattern near the coast of Bulgaria. More precisely in this paper various types of distribution were analyzed in respect to significant height of combined wind waves and swell (Hs), mean wave direction (MWD), mean wave period (MWP). The target area is located in the range 43.75°N, 42°S, 28.5°E and 29.5°S. In this analysis, five points were taken into consideration. For this study, reanalysis data coming from ECMWF (European Centre for Medium Range Weather Forecasts) was analyzed. The considered period covers 36 years of data, more precisely from 01 January 1983 to 31 December 2018. After the analysis we can draw a compressive picture of the wave energy distribution for the studied area through the considered interval. [ABSTRACT FROM AUTHOR]

A great number of agricultural structures such as irrigation and drainage systems and anti-erosion facilities like bulk shafts, terraces, grassed run-off holding collectors, barrages, wind protection belts, etc. were put into operation during the last century in Bulgaria. The Agrarian Reform of the 1990-s posed unfavorable conditions for preservation and use of this valuable inheritance. Currently, small-sized, fragmented and scattered land use causes deterioration of land quality and infrastructure. The regulatory framework in force omits the issue of agricultural land-use planning, while it is vitally needed for the territories under special use. There is lack of incentives for stewardship and use of the agricultural infrastructure, which predetermines owners’ unawareness. The paper analyses the conflicts between land and water use in the ameliorated areas, which stem from the functional disability of the amelioration systems in conditions of fragmented land use and inadequate land structural design. The analysis is supported by facts about the current state of the agricultural infrastructure and agricultural land-use issues. Legislation gaps and insufficiency of regulated planning tools for increasing land- and water-use efficiency and land conservation, are discussed. Ways for mutual improvement of land and water use within the attached to the existing and newly designed irrigation and drainage systems areas are proposed, with the idea for increasing the efficiency and the ecological effect of the costly systems. The paper focuses on land development, land consolidation crop structure and conservation measures in the ameliorated agricultural areas. [ABSTRACT FROM AUTHOR]

This paper focuses on the capabilities of Geographic Information Systems (GIS) to develop databases that support alternative tourism and, in particular, wine tourism in Bulgaria. The main task of the paper is to collect and integrate existing public and opensource graphical and attribute data. We use GIS tools to create a database, an online register, and an interactive map of wineries and wine houses according to Bulgarian laws and tradition. We create a specialized spatial GIS database containing administrative and specialized attribute data for wineries and wine houses in Bulgaria. This database can be further developed and expanded with data on transport networks, tourist flow, producers, consumers, goods, and services related to system of wine houses and guesthouses. [ABSTRACT FROM AUTHOR]

Old closed uranium mines can be a significant source of environmental pollution and hazards to human health. The problem could become more severe in time due to erosion if the restoration measures are not properly maintained. There are many uranium mines in Bulgaria that, even closed in the 1990s, could be a pollution source for surface and groundwater in their region. Through hydraulic connections, they can contaminate the rivers passing nearby. The aim of the present work was to check the hypothesis of a possible water pollution caused by a uranium mine closed and reclaimed about 20 years ago, based on the example of Eleshnitsa mine. Extensive literature survey was carried out on the publications (papers, dissertations, reports in the recent 20-25 years) presenting mainly data on parameters of surface and groundwater in the region, precipitation, surface - groundwater connection but also - mine restoration. The data were systematized, combined with our in situ measurements, sampling and analyses, and statistically processed. It has been found that sulfates (SO4 2- ) and manganese (Mn) are the main pollutants both in surface and groundwater, besides uranium (U) and total - radioactivity. The good news are that generally in the recent years concentrations of SO42- and Mn do not show a trend to an increase. Data processing exhibited existence of a significant correlation between water conductivity (EC) and SO4 2- in the studied region - both for surface and groundwater. Increased EC is also an indicative parameter for Neogene groundwater pollution with U. Elevated concentrations of SO42- are generally suggestive for increased Mn concentrations. Thus the increased values of EC can be used for an express assessment of possible water pollution with SO42- , Mn (and U for deep groundwater) caused by mining activity in the respective area. In addition, SO4 2-, as a mobile and characteristic pollutant, can be used to model the contamination spreading. [ABSTRACT FROM AUTHOR]

Transitional (brackish) water bodies host extremely vulnerable ecosystems. They are highly sensitive to pollution, changes in the water currents, nutrient levels, etc. Over the course of the 20th century in Bulgaria, many of them were purposely drained or strongly altered. Today, these fragile ecosystems account for just 0.1% of Bulgaria’s area, and hence they are listed among the country’s top priority nature conservation sites. The long-term preservation and survival of numerous rare or threatened hydrobionts depend on the conservation of these aquatic habitats. The site selected for the study herein is Maznia azmak. It represents a highly eutrophicated coastal lake (a former river bed) found in the Kamchia River’s downstream sector, contiguous to the mouth of the estuarine type, where it empties into the Black Sea. The study site represents a constituent part of Kamchia Nature Reserve and two Natura 2000 protected sites, i.e., BG0002045 Komplex Kamchia (Birds Directive) and BG0000116 Kamchia (Habitats Directive). The main goal of the present paper is to analyze the spatio-temporal changes, scale and rate of eutrophication at Maznia azmak and the related loss of sensitive aquatic habitats that are a subject to preservation. This has been achieved through GIS-based analysis and interpretation of archive topographic maps compiled at scale of 1:5,000-1:126,000, historical satellite and contemporary drone imagery. Results of the study demonstrate the constant expansion of the aquatic vegetation at the expense of open water surfaces. These findings imply for a deteriorated ecological status of the associated freshwater habitats in result of eutrophication. [ABSTRACT FROM AUTHOR]

Soil erosion is the most serious soil degradation on the territory of Bulgaria. Estimated average annual potential soil loss from sheet water erosion in Bulgaria amounts to 902.5 million tonnes. Over 68% of the territory of the administrative region of Kardzhali (East Rhodopes) is characterised by risk of sheet water erosion exceeding 100 t/ha y. The paper presents assessments of susceptibility to erosion of soils in the catchment of the Dzhebelska River (Eastern Rhodopes). The assessments are based on the USLE approach, which was adapted for Bulgarian conditions and integrated with GIS. It is established that the soil erodibility values of the soils distributed in the catchment area of the Dzhebelska River (Eastern Rhodopes), assessed as K-factor values vary from 0.005 to 0.042 t ha h / ha MJ mm. The largest percentage share (47%) of the lands in the catchment area of the Dzhebelska River is characterized by medium to high susceptibility to erosion (0.03-0.04 t ha h / MJ ha mm). Lands with low susceptibility to erosion (0.01-0.02 t ha h / MJ ha mm) have the lowest percentage share (1.72%). [ABSTRACT FROM AUTHOR]

The maintenance of ecological, economic and social functions of forest territories is closely connected with competitiveness of forestry. Its assessment permits to take the right decisions for its enhancement and rational use of forest resources. In this regard the purpose of this paper is to present the theoretical and conceptual framework for development of unified methodology for quantitative assessment of competitiveness of forestry companies in Bulgaria. The theoretical framework is based on the existing theories in the field of company competitiveness. On the basis of their study it is concluded that the quantitative indicators characterizing the competitiveness of forestry companies must meet the following requirements: practicality, which is associated with low costs for data collection; sensitivity to changes in forestry practices; objectivity and measurability; standardization within certain limits, which allows comparison of management results with the set goals. The conceptual framework of research stresses on the fact that from statistical point of view the competitiveness is a complex indicator. It is characterized by numerous manifestations, which are measured by set of simple (one-dimensional) indicators. Their processing through different statistical methods produces the value of complex indicator – competitiveness. The conceptual framework of the research requires solution of series of tasks – from justification of a system of one-dimensional indicators characterizing the competitiveness of forestry companies to collection of information about them, processing and interpretation of results through the prism of sustainable management of forest territories. The current article is dedicated to solution of this circle of issues. [ABSTRACT FROM AUTHOR]

National statistic is the most important tool for gathering information. It helps us to be analyzed on the national and local level. As a vital resource statistical information for water is the most important for predicting its supply and demand. Another aspect of water analysis is water using for both industrial and household purposes. Last but not least is water wastage. All of these aspects are vital for the Bulgarian cases because of information lack. Last year Bulgaria was faced with big water problems all around the country. The government could not have information for water wastage and some regions were faced with a water crisis in a pandemic situation. This situation shows some problems with a water supply and demand statistical information. This paper aims to analyze the Bulgarian statistic information in accordance to experiment ecosystem accounts and their technical requirements. Also, it is presenting the current statistical information for water and how it would be improved in the era of big data and IoT /Internet of things/. [ABSTRACT FROM AUTHOR]

Many studies confirm a shift to warmer climate in South East Europe. In Bulgaria, warming trends have been registered since the end of the last century, and different scenarios show increased air temperatures in the future. In the face of climate change, it is a challenge to assess its effect on water resources. The aim of the paper is to evaluate the possible impact of climate change on the discharge of two springs from the Lovech Tarnovo karst basin. This study uses the monthly water balance method to compare the future regime with the baseline regime for two karst springs. For calculations, the software WaterbalANce is applied, which is based on the Thornthwaite–Mather method. The monthly time series of temperature and precipitation for simulations are used from the meteostations neighbor to the springs (stations Pleven for Krushuna and Veliko Tarnovo for Musina). For the purposes of this study, monthly water balance calculations are performed for the baseline scenario S00 (1976–2000) and a set of future climate development scenarios Snn. The first index refers to absolute change of temperature, and the second – to relative change of precipitation. The scenarios S10 and S20 mean change only of temperature, +1.5°C and +3.5°C respectively. The S11 and S21 scenarios assume a 10% decrease in precipitation in addition to the corresponding temperature changes. The input data for any scenario other than the baseline scenario are obtained by corresponding changes in the time series of temperature and precipitation. The results of the water balance calculations show the negative impact of the increased temperature (flow reduction for the Musina spring by 13% and 25%, respectively, only for temperature change, +1.5°C and +3.5°C, respectively). An additional 10% reduction in precipitation will lead to a 33% and 44% drop in average discharge, respectively. Similar results are obtained for the flow rate of the Krushuna spring. Overall, these results show the serious negative impact of future climate change on the discharge of the studied springs. [ABSTRACT FROM AUTHOR]

Water management in karst areas is a challenge as the regime of waters is generally characterized by substantial temporal variability. Water balance analysis is a necessary part of hydrogeological research. The aim of the paper is to study specific features of the water regime and balance of karst springs from the Lovech-Tarnovo karst basin, as well as to evaluate their recharge area. For monthly water balance calculations, the software WaterbalANce was used that is based on the Thornthwaite–Mather method. In addition, the chloride-mass balance was applied to evaluate the recharge area of the studied karst springs contributing to their discharge. The studied karst springs are located at the villages of Musina and Krushuna. The information base includes mean values of the chloride concentration of the spring waters as well as the monthly time series (long several decades) of springflows. The results of the water balance calculations show that the simulated time series of the discharge values give reasonable results. The largest differences between the measured and modelled data were found for the extremes (highs and lows) of the monthly values of the spring discharge. The studied springs are highly vulnerable to droughts. This is due to the limited storage capacity of the aquifer and, therefore, to low static reserves, since there are no conditions for deep karstification. Droughts, especially during the cold half of the year, have the strongest effect on the regime, even if the amount of precipitation in the warm half of the year is around the norm. Obviously, winter precipitation is the most important source of groundwater recharge for the karst basin. [ABSTRACT FROM AUTHOR]

Flood events, as well as the channel and floodplain landforms are crucial for the transport and spatial distribution of heavy metals and metalloids in soils in the river valleys. The paper outlines the results of obtained preliminary indications about the flood proneness of two study areas located in the valleys of Ogosta River near the village of Gorna Kovachitsa and Lom River near the village of Vasilovtsi (NW Bulgaria) based on hydro-geomorphological indices. The detection of flood-prone areas has been done using two key data products of UAV photogrammetry data ? the digital terrain model (DTM) and the orthophotos with grid size 1 m. Flood-prone areas have been identified using GIS techniques based on several hydro-geomorphological indexes extracted from digital terrain models (DTMs). Firstly, they were evaluated individually by their hydro-morphographic and topographic meaning according to the literature and analysis in geomorphological context, as well as through defining thresholds and analysis in topographical context to select the best performing classifiers. Secondly, the selected hydro-geomorphic descriptors have been binary classified to distinguish between flood-prone and non-flooded areas and used for creation of binary flood-prone areas maps, which were merged together and evaluated according their altitude above the river. A second methodological approach applied in this work is based on calculation of potentially flood areas from the raster “Vertical Distance to Channel Network” using the GRASS GIS module r.lake implemented in QGIS and binary classification. The orthoimages were used for extraction of the rivers geometry using object-based segmentation and classification. Additionally, the obtained results have been compared with the previous flooding data in the area of Ogosta Valley near Gorna Kovachitsa from flood in 2014. The obtained results highlight the potential for the GIS-based detection of flood-prone areas over ungauged areas and will be used for modelling the spatial distribution of heavy metals in soils in the study areas. [ABSTRACT FROM AUTHOR]

The use of unmanned aerial vehicle systems (UAVs) for the acquisition of images, which are then processed by the photogrammetric method SfM (Structure-from-motion), is increasingly established as a suitable workflow for obtaining high-resolution topographic data (HRTD). Using PPK (Post-Processed Kinematic) solutions for UAVs can provide accurate parameters for the external orientation of the cameras used in UAVs for photogrammetric capture. The use of such an approach has the potential to become an alternative to the use of ground control points (GCP) for georeferencing of the topographical data obtained from unmanned aerial systems. The conventional method of georeferencing by monitoring GCP provides reliable positioning accuracy in location but critically depends on the number and spatial location of ground control points. This limits the efficiency of the method in a time aspect. Applying direct georeferencing of images taken by UAVs can overcome these limitations. This paper presents an assessment of the geospatial accuracy of three-dimensional photogrammetric products obtained by UAVs-photogrammetry using the SfM-method (Structure from Motion), combined with a PPK (Post-Processed Kinematic) solution for coordinating the taken images. The study was performed with VTOL WingtraOne, which is equipped with a Sony RX1R II camera with a 35 mm full-frame sensor and 42 Mpix resolution and an additional PPK GNSS module AsteRx-m2 UAS for direct georeferencing of the images. Digital data generation was performed using two georeferencing methods: 1) Aero Triangulation – “AT” (GCP method) and 2) Direct image georeferencing (PPK method) without the use of GCPs. The results of the application of the method in the case study area of Gorna Kovatchitsa, show that it provides very accurate digital data for the terrain, allowing rapid analysis of river valleys. [ABSTRACT FROM AUTHOR]

The largest damages and environment contamination are caused by the mining and mineral processing industries, as well as the power and chemical industries. That is why when we are speaking of damaged terrains reclamation and soils, first of all we understand reclamation from the impact of these anthropogenic activities. Reclamation places many questions from an economic, social, technical and scientific viewpoint. Reclamation is a complex approach to sustainable management of land degraded as a result of natural or anthropogenic activities. Reclamation of mining damaged landscape is a complex activity aimed to the land restoration for future rational and environmentally sound use. Restoration of damaged areas creates more productive anthropogenic landscapes and habitats of different species. Damaged mining terrains reclamation is a current and complex problem, as an individual approach to each specific object is needed. In recent years there has been a trend towards a humus negative balance. As a result, thousands of hectares of degraded land are deprived of conventional restoration processes that require humus use. This fact marks the beginning of a new technological approach to environmental management - “non-humus reclamation”. The aim of this paper is to broadly explore the properties of the anthropogenic soils from Vetovo region, Bulgaria, Kaolin AD. The soils are formed as a result of the accumulation earth material extracted with open pit mining. Scientific and research program has started to establish the opportunities for anthropogenic soils non-humus biological reclamation. The technogenic soil agrophysical properties were studied and determined. The aim of the program was restoring the function of damaged lands and balanced ecological systems creation. Lastly the conclusions are presented. [ABSTRACT FROM AUTHOR]

Debris flows are considered as flows of highly liquefied sediments in mountain areas, usually triggered by intensive rainfall or snowmelt. They move rapidly through the transport channel or a gully and accumulate the debris material on a less slopping or flat areas, forming a debris fan. Often debris flows occur suddenly and could affect infrastructure as well as to influence human activity and life. This determines the growing need to deepen the research of the debris flows and to take into account the peculiarities of their occurrence in the strategies and plans for territorial development. In the current paper main morphometric parameters of debris flows area in the watershed of the river Byuyukdere (Southern Bulgaria) and characteristics of debris flow deposits are presented. Geomorphogical settings derived from the morphometric analyses and field research are considered as prerequisites for debris flows occurrence and propagation. Morphoscopic and grain-size analyzes are used to characterize the sediments and the conditions of their transport and accumulation. The calculated values of sorting coefficient of the deposits, in a range of 2.08 to 4.68, indicate the turbulent depositional environment and the flow dynamics. [ABSTRACT FROM AUTHOR]

Groundwater is one of the main resources for drinking- and industrial water supply in Bulgaria. Investigations of a number of groundwater sources indicate concentrations of toxic elements or metal ions, considerably exceeding the maximum contaminant values. Pollution with arsenic has been found in the region of Dimitrovgrad, Merichleri, Haskovo, Kyustendil. Increased content of manganese, iron and sulphates is available in some districts of Sofia, Dimitrovgrad, Haskovo, Svishtov. Presence of excessive concentrations of toxic hexavalent chromium has been found in the water of Pleven region, Montana region, Vidin region, thereby creating serious problems. The accumulation of hexavalent chromium in the human organism may bring about necrosis of liver, irritation of the gastrointestinal mucous membrane, increased risk of lung cancer. The main problems standing before the companies exploiting groundwater sources with chemical pollution are related to the choice of an economically beneficial alternative guaranteeing the safety of water used for drinking, household and industrial purposes. In this aspect, the identification of the origin (natural or anthropogenic) of certain pollutant is extremely important for making decision - finding and termination of the anthropogenic pollution, water treatment or seeking another water source. In the paper, the authors suggest a complex approach for determination of the chemical pollutants' origin in the groundwater, based on multi-factor analysis combining historic data, hydrogeological studies, geochemical and hydrochemical analyses. The methodology is used in studying the origin of manganese, iron and sulphates with excessive concentration in the groundwater in different districts of Sofia, the results obtained being given in the paper. Currently, the combined approach is being updated in order to be applied in studying the origin of toxic hexavalent chromium in the ground water in the region of Pleven, Northern Bulgaria. The main point in the suggested methodology is the long-lasting run-out of groundwater which causes a temporary change of the direction and flow rate of the seepage stream. The change of the concentration of the studied pollutant before, during and after the seepage test gives information for the point of entering and the way of distribution of the pollutant in the groundwater. The obtained data are combined with determination of the mineral and chemical content of the rocks in the water bearing layer, and with data for the sources of anthropogenic pollution in the region. [ABSTRACT FROM AUTHOR]

The current methodology of geography training in secondary school is aimed at finding opportunities for the implementation of an effective educational process.Recent studies prove the effectiveness of the so-called outdoor lessons. And this is no coincidence, given their impact on learning motivation intraining process. They practically operationalize the methodological principle of "learning through experience",especially relevant to modern didactic. However, how can this type of lesson be organized in the context of a centralized classroom educational system? In our opinion, a study excursion(field trip)is a very good option. In comparison with the traditional geography lesson, it shows a number of advantages: it promotes the development of one's own experience, develops an emotional connection with the homeland and the living space, emphasizes the social importance of geography, contributes inevitably to the development of environmental education in students, it is a main aspect of sustainable development education, etc.Of course, the implementation of a study excursion(field trip) is accompanied by a number of problems and difficulties, which in our view could be over come and justified. This is the basis for a deeper study of the issue in future. This paper proposes the most general up-to-date characteristic of a study excursion(field trip)in geography training in the context of educational tourism.The author explores the essence, typology and ways of implementation of field trips. Specific possibilities for their realization in the border municipalities of the Republic of Bulgaria with the Republic of Serbia are indicated.The author highlights the promotion ofthese municipalities as places for extra-curricular activities and defines these territories as suitable for organizing specific educational tourism. [ABSTRACT FROM AUTHOR]

The paper aims at analysing the effect of different motivational drivers and moderating factors to the activation of sustainable behaviour in its two main forms – consumption and involvement. Further it aims at testing the relationship between activism and the choice and usage of products in a sustainable manner. To fulfil these tasks a theoretical model is designed on the basis of previous quantitative and qualitative research on the antecedents of sustainable behaviour. The research builds on a survey with a sample of 212 participants from Bulgaria with a different background. To analyse data there were used hypothesis testing and regression analysis. The results from the study confirm the moderating effect of locus of control and self-efficacy emphasized in literature and provide evidence for the relation between sustainable behaviour and activism. The findings, however, reveal also that behaviour, often categorized as sustainable (the triad reuse-reduce-recycle and active citizenship) is predominantly driven by factors other than the typical eco-centric values. These conclusions point on the need for rethinking how sustainable behaviour can be activated and can guide policy makers in designing a system of measures to help the transition to sustainable development. The results from this study can also assist responsible companies in building strategies for growing the segment of sustainable consumers and can be used to help further research on the relationship between sustainable consumption and involvement to track cross-national differences on similar markets. [ABSTRACT FROM AUTHOR]

The main difficulties nowadays in Bulgaria in agricultural land governance, land administration and land management stem from weaknesses in the legal framework. To this can be added the historically accumulated lack of interest in land stewardship and the inherited soil degradation processes. Nowadays chaotic land use does not provide territorial conditions for taking advantage of modern agricultural technologies. The socio-economic development requires complicated interaction between the private, state, municipal, and public interests in agricultural land-use. The main issues are the protection of land tenure, conservation of soils, protection of the environment, and economic prosperity of the farms and regions. Solving them requires a number of activities such as conducting research on soil quality and their condition; land capacity assessment; land valuation, development of agricultural cadastre; taking measures to limit the processes of soil degradation, protection of the environment and the landscape and as a basis for all these activities - agricultural land-use planning. The purpose of the paper is to present the results of a questionnaire among professionals and producers in agriculture, to make an analysis and to draw conclusions about the need for agricultural land-use planning. With a critical approach of the authors, new principles and new characteristics of agricultural land use planning have been developed. [ABSTRACT FROM AUTHOR]

The ore extraction from Krumovo deposit, located at the northern periphery of the Manastir heights in Southeast Bulgaria started in 1906 and continued till 1986. The ore comprised Fe3O4 with admixtures of sulfides such as pyrite, pyrrhotite, marcasite and chalcopyrite. Open pits and underground workings were used. The excavations severely degraded the habitats, vegetation and waters on an area of about 3 km2. By 1986 waste rock(comprising hydrothermally altered basic magmatic rocks, such as gabbro or diorites, magnesium skarn fragments,poor grade ore and various sulfide rich alteration products) and small open pits of various sizes were spread all over the area. The underground workings were connected with inclined galleries, from which waste waters drained.Since 1986 the waste rock has been subjected to secondary extraction for use as a construction material, which resulted in its nearly entire removal. It is worth seeing how 114 years after mining commencing, and 34 years after its stopping, the nature has managed to cope with the damage. Environmental components have been studied with emphasis on water. In previous years, the authors performed hydro chemical studies in this region and the data can be used to compare the water quality in Krumovo deposit area with the overall regional water properties. Water from two ponds in the Krumovo iron deposit was studied. These ponds differ in the water residence time as one is seasonal, while the other keeps water yearly. Data on integral water characteristics(such as pH,Eh,conductivity,and dissolved oxygen), water macro components, as well for microcomponents (such as Co, Cu, Fe, Mn, Ni, Cr, PO43-, NO3-) are presented in the paper. It has been found that the water in Krumovo is reasonably pure compared with the surface water from the region. There are reasons for this observation: (i) The regional waters are influenced by the parent rock material, and especially by the calcrete deposits, which are found immediately under the organic soil layer. As a result,water neutralization (sometimes alkalization) is observed-causing precipitation not only of carbonates but also of heavy metals -pollutants;(ii) The water sources contacting with the agricultural land in the region are affected by fertilizers' use. The Krumovo deposit is located in a hilly area, which is naturally forested and thus not subjected to the pollution from the agriculture.After the end of mining, bushes and trees germinated in nearly every crevasse in the rock and concrete wastes, providing nearly continuous vegetation cover. This contributes to the quality of the waters and provides conditions for recovering of the lost soil;(iii) Nearly 40 million tons of waste rock, as well as the abandoned concrete structures, were removed, thus eventual continuous pollution sources were withdrawn. [ABSTRACT FROM AUTHOR]

It is well known that geomagnetic fieldvaries in time,as well as in space. Besides, the world magnetic models which are the main sources of information concerning the values of geomagnetic field elements in a particular place,we present more precise and accurate model of these elements covering the territory of Bulgaria. Our study uses information from the last absolute geomagnetic survey involving measurements in473 points, secular data from Panagyurishte(PAG) and several other Intermagnetobservatories near Bulgaria,as well assecular magnetic measurements of the Bulgarian network.Above and beyondthe scientific investigation which are performed using geomagnetic field values, this information has also practical application. The most significantelementis the geomagnetic declination, which is widely used in geodesy, cartography and their associated navigational systems. The geomagnetic declination is very important for navy and aviation (civil or military), radio connections, etc. As the geomagnetic field changes with time, the topography maps has to be updated regularly. Each edition must have a reliable value of the geomagnetic declination to allow orientation with the help of a compass. Present paper gives most up-to-date models of the total geomagnetic field (F), horizontal component (H) and declination (D) over the whole territory of Bulgariadetermined for the 2020.0 epoch.The observatory measurements, existing records and calculations of geomagnetic field elements are also described. [ABSTRACT FROM AUTHOR]

The territory of Bulgaria represents a typical example of high seismic risk area in the eastern part of the Balkan Peninsula. The spatial distribution of seismicity in Bulgaria is uneven, which gives reason to group earthquakes into geographically defined zones -seismogenic zones. In the present study the Sofia seismogenic zone will be examined.Sofia seismogenic zone is located in southwestern Bulgaria -the area with pronounces tectonic activity and proved crustal movement. The capital of Bulgaria-the city of Sofia represents a typical example of high seismic risk area. Over the past centuries, the city of Sofia has experienced strong earthquakes. In historical aspect, it is worth to mention the 1818 (I0=8-9 MSK) and the 1858 (I0=9 MSK) earthquakes occurred near the cityof Sofia. The 1858 earthquake caused heavy destruction to the city and the appearance of thermal spring.During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MW5.7(I0=7-8 MSK). Almost a century later (95 years after the 1917 earthquake) an earthquake hit Sofia seismogeniczone, on May 22nd, 2012 with moment magnitude MW5.6 (I0=7-8 MSK).In nowadays Sofia zone is characterized by a long quiescence for strong events. Moreover, a reduced number of small earthquakes have also been registered in the recent past. The manifold purpose of our study is first to examineseismicity in Sofia seismogenic zone and surroundings from the past to nowadays,then toanalyzethe space-temporal pattern of earthquake distribution in the zone. The prime result of our paper is the discovery that the space -temporal distribution of earthquakes in the Sofia seismogenic zone is non-uniformboth in space and time. [ABSTRACT FROM AUTHOR]