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The study presents results and discuss statistical properties of wind-generated sea waves measured in transitional waters of the Burgas Bay at the Bulgarian Black Sea. Wave measurements were acquired by Acoustic Doppler Current Profiler at two locations offshore Kraymorie and Chernomorets at water depths of approx. 15 m and 18 m, respectively. At each location, data were recorded for about three and a half months in winter seasons of 2021-2022 in front of Chernomorets and in 2022-2023 offshore Kraymorie, when stor...

The article presents the results of population studies conducted in the floodplain of the Seim River within Sumy region, Ukraine. The ontogenetic and vitality structures populations of Potentilla erecta and Althaea officinalis. During the study, the following methods were used: the geobotanical method, morphometric analysis, complex vitality analysis. In general, for the region of research on P. erect- priority is the introduction of active protection measures aimed at increasing the distribution centers and the f...

Precipitation is the main source of recharge of water resources, thus guaranteeing their renewability. Not only hydrometeorological changes, but also anthropogenic factors exacerbate the above-mentioned effects. The increase in the level of investment seen especially in recent years in urban agglomerations through the intensification of development, increased development of impervious and paved surfaces, the use of vacant land, and thus the reduction of biologically active areas has resulted in an increase in rain...

The Danube Delta is a wetland of global importance, providing several ecosystem services. The sustainable development (i.e., economic, social and environmental) in the area depends on the health, quality and quantity of the natural resources. Water is one of the most important resources. Largely, the Danube Delta, which receives the input of water and sediment flux from the Danube River, gathered form its entire basin, may experiences lower water quality due to natural and anthropogenic factors, from basin to loca...

In recent decades, small domestic wastewater treatment plants have become popular in rural areas of the Slovak Republic. The reason for the expansion of decentralized wastewater management is that many rural areas have scattered settlements, and a centralized wastewater disposal system is economically, technically demanding, and inefficient. The disadvantage of using small domestic treatment plants in terms of environmental protection is that these facilities have yet to be significantly monitored. Due to improper...

Knowledge of the coastal hydrodynamics, in particular the storm induced waves, is essential for management of the extremely vulnerable coastal environment. There, wave processes dominate surge, coastal currents, sediment transport and species distribution. Therefore, it is important to have a detailed insight into the exposure of different coastal areas to wave action. The study proposes a wave exposure classification of the Bulgarian Black Sea coast according to wave climate conditions as required by the Water Fr...

Water resource of a given river basin is the main component of the ecosystem and water resources management system as well. Ecological flows are considered within the context of the Water Framework Directive (WFD) as -a hydrological regime consistent with the achievement of the environmental objectives of the WFD in natural surface water bodies as mentioned in Article 4(1). The so-called Heavily Modified Water Bodies (HMWB) or -regulated rivers- have modified flow, which is influenced by reservoir compensation rel...

The study is focused on statistical analysis of river discharges. The registered river flow regime and hydrological characteristics of Yantra River are investigated. Yantra watershed is situated in North Bulgaria and belongs to Danube river basin Directorate. The current study is focused on the low flows. Thirteen hydrometrics stations located in the watershed are available for the investigation. Data used are from monitoring network of the National institute of meteorology and hydrology, Bulgaria. The flow durati...

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...

Compliance with EU environmental regulations and directives regarding effluent water quality discharged is seen as the main driver for the development of wastewater treatment technologies. The Water Framework Directive, the UWWT Directive, and the Nitrates Directive require the reduction of eutrophication caused by nitrogen and phosphorus emissions. In Romania, only approx. 54% of the population is connected to centralized sewage and wastewater treatment systems, meaning that approximately 8 million inhabitants ar...

The largest aluminum factory in Eastern Europe is located near Slatina. Before Romania acceded to the EU in 2007, many environmental protection rules were omitted in this area. The paper analyzes the water table pollution along the Olt River for about 15 km. There are considered the tributary flows on the river, the concentration of discharged pollutants, and the pumping regime from the catchment front. It is built at about 500 m from the river, on the left bank, parallel to the river, and consists of 44 wells, of...

Water pollution and climate change are two of the most pressing environmental challenges of our time, and their interconnection is increasingly evident. Water pollution and climate change are interconnected in various ways. The release of greenhouse gases, primarily carbon dioxide, methane, and nitrous oxide, is a significant driver of global warming. These gases contribute to the greenhouse effect, leading to rising global temperatures, which, in turn, affect water resources. Warmer temperatures exacerbate water ...

Among the many factors affecting the average life expectancy and mortality of the population, along with the effective services of the health care system, an important place is occupied by the ecological condition of the environment, in particular, the quality of the security of its resources for human health. Providing the population with safe, clean, drinking water is one of the most important factors in the world and among them in Georgia. According to the data of the World Health Organization, almost 2 billion...

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 meteo...

The purpose of this paper is volumetric quantification of soil erosion using the so-called erosion bridge. For the measurement, a locality in the South Moravian Region of the Czech Republic was chosen. With the erosion bridge, we can measure erosion rills. Rill erosion is caused by concentrated water flow. It occurs when runoff water forms small channels as it concentrates down a slope. The erosion bridge is a very simple device that enables us to accurately measure the shape of the soil surface in a given place. ...

The article discusses the efficiency of vertical subsurface flow filters in wastewater treatment wetlands, where the main filtration layer is composed of recycled aggregates. To determine the efficiency of the vertical filter using modified recycled aggregates, three test columns were created. The first column contained natural gravels, while the second and third columns used masonry (RMA) and concrete aggregates (RCA). The test filters were loaded with wastewater from a combined sewer system, with non-dissolved s...

Water is one of the basic necessities of life. However, water crises have become more frequent around the world as billions of people continue to suffer from a lack of access to clean water, sanitation and hygiene. Water is a limited resource that has been in growing demand - with the world's population increasing and water-intensive economic development continuing, infrastructure of many countries is not fit to meet accelerating demand. With climate change and its variability fluctuations in rainfall and extreme ...

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 f...

The current weather patterns, in the form of more frequent occurrences of hydrological extremes, are increasingly being felt in the Czech Republic. In this context, the paper focuses on the issue of the current management of the landscape, which loses its quality due to these adverse climatic conditions and the influence of man. The aim is to compare selected physical properties and obtained soil moisture data for different uses and cultivation. For sample collections, a site in the Czech Republic in the South Mor...

Evapotranspiration is an important component of hydrological balance, and it represents a complex process of water evaporation form water bodies, soil and plants. The Food and Agriculture Organization of the UN proposed the Penman-Monteith equation as the most reliable method for calculating reference evapotranspiration. However, the application of Penman-Monteith is often limited in many regions, due to the requirement for a large amount of meteorological data. In such circumstances, it is necessary to identify a...

Manual measurement of flow velocity and streamflow discharge during high waters is often impossible because of different factors: night events, harsh meteorological conditions, very high dangerous river velocities and levels or infrastructure destruction. The purpose of this study is to determine maximums of river flow velocity and streamflow discharge with hydraulic engineering methods, as well to determine the modulus of runoff at some stations in the East Aegean River Basin in South Bulgaria for the period betw...

The development of indicator systems for drought identification is part of the Drought Management Plans. The analysis of the correlation between the different indices is an essential part of the indicator systems. That research is part of a task related to the developed at NIMH system (http://hydro.bg) of drought indicators and the development of recommendations for their simultaneous use. For this purpose, the influence of climatic factors on the hydrological cycle components and the role of the characteristics o...

Due to the population increasing in urban settlements, the use of the territory and the surface variability of urban settlements are changing rapidly. The development of areas covered with impervious materials contributes to accelerating the runoff process, intensifying surface runoff concentration and the concentration of surface runoff pollution. Surface runoff from urban catchments can be characterized as the primary source of the receiving water's pollution during torrential rains. The aim of the paper is to o...

Drought indicator systems help decision-makers to understand how and where the drought occurred and to take measures from the Drought Management Plans. The main goal in the Water Framework Directive (WFD) is the achievement -good ecological status-, but the Article 4.6 allows temporary deterioration of the status, occurred as a result of so called -prolonged drought-. Reduction of natural water resources such as rivers, lakes, aquifers, is associated with the reduction in available water resources for water supply...

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 scientificall...

Since the beginning of hostilities in the Ukraine territory, there have been several cases of detonation of dams on reservoirs. These events affected the surrounding areas, leading to a flood of different degrees. One of the significant cases occurred on the dam covering the Irpin river, close to Kyiv. It was built during the Kyiv Reservoir filling to prevent the flooding of the river valley and serves as a bridge. After a part of the dam was broken, water from the Reservoir began to fill the Irpin river. The floo...

The use of pesticides has negative effects on the quality of groundwater. The triazine pesticide atrazine has not been applied to soil in agriculturally used areas of the Czech Republic for many years, yet atrazine and its metabolites are detected in groundwater throughout the country. The effect of these substances on the denitrification process that takes place in groundwater is unclear. This study aims to examine the behavior of atrazine under denitrifying conditions and the pesticide-s effect on the denitrific...

The purpose of the publication is to clarify the flood causes and consequences that occurred on 06.02.2012 on the Maritsa River near the town of Svilengrad. For this purpose, a survey of literature sources and technical documentation was carried out to clarify the main natural-geographical and anthropogenic factors for the formation of high waters of the Maritsa River and the manifestation of the flood in town Svilengrad. Based on this, as well as on field work, information for the creation of GIS databases for th...

It proved experimentally that for neutralized sea water (removal of microorganisms) may be used electro dialysis device, as its economy and proper quality of sea water are justified. Research data need to refine and continue in this direction. At three locations in the Adjara coastal zone of the Black Sea (Pichvnari, Kvariati, the coast of the Batumi port), as a result of Electro dialysis, recorded more than effective ion removal NH4+ - ions, than NO2- -ions. As a result of electro dialysis, the concentration of b...

Kherson region has the largest share of irrigated land among all regions of Ukraine. At the same time, it is the largest arid region with a significant area of drainageless massifs. All this contributes to the occurrence of flooding of territories. The main task of the research is to identify modern factors of flooding of settlements in the Kherson region (Ukraine). The goals of the study were to analyze the hydrogeological conditions in the places of flooding, to identify modern changes in the rainfall regime and...

The theoretical model of perfect business competition is designed based on five assumptions: atomicity of demand and supply, homogeneity of the product, free entry/exit in/from a branch of activity or on/from the market, market transparency, (with the fundamental assumption of the individual's rationality) and perfect mobility of production factors [1], [2]. The factorial analysis carried out for an economic agent from an Eastern European country highlighted the fact that the production function is homogeneous. Fo...

In the presented article the reason of the village Anaklia territory, the site of the planned construction of a deep-sea commercial port- flooding is discussed. It should be noted that the village mainly is located on the sandy shore of the river mouth of river Enguri. In calm, but rainy weather, precipitation practically freely penetrates through the sandy soil without leaving any water holes and flooded land areas after the rain. However, on March 24-25, 2021, in rainy weather and stormy seas, the village was pa...

The purpose of this study was to demonstrate the role played by different wastewater treatment technologies in the dairy industry in the context of the challenges of sustainable development: water scarcity and conservation of water resources, the constant growth of the population and the costs of wastewater treatment in centralized systems, increasing constraints and stricter environmental protection regulations. In this sense, the efficiency of wastewater treatment plants belonging to a number of 8 factories was ...

Hydrological extremes (drought-flood) are a phenomenon that is occurring more and more frequently because of climate change. The human-altered landscape cannot sufficiently withstand these extreme phenomena. For this reason, society feels pressure on the design, and assessment, but especially the implementation of adaptation and mitigation measures in the landscape. For best-designed measures, it is crucial to determine where the given problem arises and what are the possibilities of its solution with subsequent q...

In recent years, natural wastewater treatment wetland plants have been gaining more attention from researchers and the public due to their low operating costs and efficient way of treating wastewater. Treatment wetland plants with pulse-fed vertical flow filters are one of the most efficient treatment technologies. For optimum operation, intermittent loading of wastewater onto the filter surface is necessary, for which various types of automatic siphons can be used in addition to pumps. This kind of automatic siph...

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 [1]. Flash flood forecasting is still a challenge for hydrologists and water professionals due to the complex nature of the event itself. ...

Floods are one of the deadliest natural disasters in the world. According to the World Meteorological Organization (WMO), this is a consequence of the increasing frequency of heavy precipitation, changes in upstream land use, and a continuously increasing concentration of population and assets in flood-prone areas [1]. For this reason, flood prevention, and protection are a growing priority these days. Flood hazard mapping is a state-of-the-art tool for decision-makers and stakeholders when it comes to flood prote...

Several geochemical analyses (bulk parameters, particle size, loss on ignition, major, minor and trace elements) were performed on 51 recent sediment samples collected in May 2022 from Rosulet, Rosu and Puiu lakes which are located in the fluvio-marine delta plain of the Danube Delta, Romania. The aim of this study was to decipher the potential origin of anthropogenic and/or natural sources, weathering, sedimentary processes and the local geochemical fingerprint on the distribution of specific chemical elements in...

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 p...

In recent years, the growing impact of flood events on society, economy and environment, has increased the need for early prevention and mitigation measures. The prediction of future flooding areas represents an important tool that can reduce the magnitude of consequences, by identifying and mapping the flood prone-areas. The intensity and extension of floods depends on various contributing parameters, such as hydrometeorological and geomorphological indicators, land use, anthropic activities. Therefore, by analys...

Climate change-s effect on nature, the human population and water resources have become a serious issue. It affects the delicate balance between precipitation, evaporation, discharge and other interactions between the atmosphere and surface, which is represented by the water cycle as we know it. The adaptation of water resources to changing hydrological conditions within basins is crucial. However, the uncertainty of climate change makes it difficult for hydrological models to evaluate future conditions. To suppre...

Many national and international agencies and organizations collect and provide open access to data on parts of the Earth's surface covered by water. Data on ocean temperature and acidity, precipitation, river flows, lake, sea, and groundwater levels, and many other open data sets allow researchers to monitor and observe water at different scales and time frames, and to better understand ecological processes and human impacts on the water environment. The main challenge in analyzing the vast amount of openly availa...

The Water Area Management Plan 2016-2021 assessed reservoirs as natural water bodies. This assessment included their ecological condition. The goal of the intercalibration procedure is to achieve consistency, comparability of results and evaluation of the ecological state based on the biological element of macrozoobenthos quality. The paper presents the results of research on the Cakovec HPP and Dubrava HPP reservoirs on the Drava River from 1999 and 2003. Complex studies of individual biological elements of macro...

River hydrology is a key component in river resources planning and river engineering. Our recent study is focused on flow metrics that best describe the registered flow regime and hydrological characteristics of rivers within the Tundzha watershed located in South Bulgaria. The flow regime will be described using 5 broad categories: magnitude of river flow; frequency; duration; timing and rate of change. A special attention in the research was given to the low flows. Thirteen hydrometrics stations were selected fo...

Currently, many emphases are placed on the possibility of limiting excavation works in the event of water pipelines or sewage systems failure. For this purpose, various types of inspection and repair robots/manipulators are used, which can enter the installation's interior without the need to get into the pipe physically (e.g. with an excavator). Mobile robots allow you to diagnose the problem (or provide information on which section the failure occurred) and in some cases, to repair (unplug) the installation with...

Teichi bog is largest intact moss bog in the Baltics states. The article considers the hydrological exchange process of the bog and surrounding areas. It plays an important role in the ecosystem, as well as a factor in stabilizing the water level, as bog peat in its natural state contains 88%-97% water. It belongs to raised bogs, since its upper layer is located above the surrounding relief. Replenishment of water resources in the Teichi Nature Reserve occurs mainly due to precipitation. In turn, the bog with surf...

The development of sustainable ecosystem services worldwide is one of the priority issues in the context of environmental protection. Sustainable use of ecosystem services ensures the conservation of natural resources for future generations. In the cold climate of the lowland river, there is a highly seasonal hydrological regime affecting the use of ecosystem services. Biodiversity in flood meadows depends directly on seasonal variations in water levels. Balanced hydro generation and water regulation can pose risk...

This study presents a new approach to optimize the habitat mapping process of the Posidonia oceanica algae on the east coast of the Adriatic Sea. Mapping of underwater and coastal habitats in the Adriatic Sea, until now, was conducted by direct methods (diving, drop-down camera, etc.) in combination with indirect modelling, which in the majority of cases results in data heterogeneity. The mentioned approach has proven unreliable, expensive, and only informative. Modern indirect, remote sensing methods enable an an...

Estradiol, also designed as 17- ? -estradiol, belongs to the pharmaceutical class of steroid estrogens and was included in the -Watch List- since 2013 the Directive 2013/39/EU due to its potential risk to human health and environment. The low removal efficiency of estrogens by the conventional wastewater treatment plants, becomes a major source of their release into different aquatic matrices. This work presents the optimization of an analytical methodology based on solid phase extraction and high-performance liqu...

The treatment of the Pasig River water using ultrafiltration is a promising solution that may help address issues on public water quality and availability around Metro Manila, Philippines. To improve the treatment performance, ultrafiltration can be applied with coagulation and adsorption. In this study, the effectiveness of ultrafiltration in treating the Pasig River water with dual coagulation and adsorption was investigated by determining the percent removal of TDS, turbidity, Escherichia coli (E. coli), nitrat...