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Modeling is important for river system analysis and management. The aim of the research is to apply disaggregation models to data with recovered natural river flow of Osam River located in North Bulgaria. As a result river discharge synthetic sequences are generated on monthly and seasonal discretization. We want to test applicability of the models for specific climatic, hydrological and orographic conditions in Bulgaria. Disaggregation models are from the family of stochastic models. Disaggregation models could b...

Most of the suspension matter transported by rivers derives from the riverbed erosion. Complementary, the anthropogenic factor is responsible for the introduction of significant amounts of sedimentary material, especially suspended, but also dissolved material. In most cases, the distinction between naturally occurring materials and anthropic ones is almost impossible to achieve due to the complexity of the erosion processes. The suspended sediments concentration (SSC) and discharges were analyzed in the Danube De...

Land reclamation is an improvement of land, which reduces the adverse effects of climate conditions and ensures the sustainable use of natural resources. Latvia is in humid soil area, which means that soils are formed under wet conditions. During the spring and autumn, these soils are wetted and unsuitable for land treatment. The installation of drainage systems shall ensure the reception of excess humidity and its removal from agricultural land, which makes it possible to process the land and to carry out economi...

Balanced development of ecosystem services in regions is one way of achieving the UN's sustainable development goals. Ecosystem services are divided into three main groups: First delivery services. Nature supplies us food and drinking water, raw materials and alternative energy sources. Thanks to natural biodiversity, we can grow a variety of vegetables and fruit, gather berries and mushrooms in the woods, and fish in the sea, rivers and lakes. Nature also supplies drinking water, which is the source of life for e...

The Danube-Black Sea Channel, inaugurated in 1984, although it has a dark history, is also of significant importance at European level, being the third longest navigable channel in the world, after the Suez Channel and the Panama Channel and connects the North Sea to the Black Sea through the Rhine-Main-Danube Channel, shortening the route of goods transport from Australia to Central Europe by 400 kilometers. The channel has a total length of 95.6 km and consists of two branches, a main one having 64.4 km long and...

The main objective of the study was to estimate the level of shallow well water pollution and the impact of natural and anthropogenic factors on it and to use the research results for the prognosis of the pollution level and the reduction of pollution. The subject research is water of shallow wells. Analysis of the shallow well water quality has been carried out in Lithuania, Kaunas region, in 83 shallow wells. Wells situated in Pypliai village were chosen for a more detailed examination. Shallow wells are usually...

In many cities from Romania, the water supply systems are very old, sometimes having over 60 years after their commissioning. Under these conditions, permanent large leakages are recorded. They are significant for the operator, influencing its economic performance and operating costs. The water supplier must understand the mechanism of water leaks and their influence on the performance of distribution network. The losses recorded by the system are unused for the purpose for which the supply was made, representing ...

Changing climate variability and the type of land use are the main factors influencing the hydrological regime. The hydrological regime of the lake has a direct impact on biodiversity and has an impact on socio-economic processes in areas adjacent to the lake. The aim of the study is to predict and assess the impact of climate change and the change in the type of land use on the hydrological regime of Lake Usma. Two linear land-use change scenarios were used for modelling. Twelve climate scenarios were used to mod...

The variation in time and space of the groundwater level is conditioned by the variation of climatic parameters. In the current context in which climate change is characterized by periods of prolonged drought and the distribution of precipitation is of the rainfall type, with large amounts of precipitation in a very short time, the groundwater level has accentuated periods of consumption to the detriment of accumulation episodes. In a first phase, the high values of the temperature superimposed over the periods wi...

The case is considered when at the Koknese district in Latvia the hydrogeological situation for dolomite excavation quarries is heterogeneous. The place geological build is complex and the quarries are situated close to large surface water bodies represented by the Daugava river and by the Urgu reservoir. The depression cones of the quarries were obtained by using the local hydrogeological model (HM). The primary data for creating the local HM were provided by the regional HM of Latvia LAMO4. The Groundwater Vista...

The purpose of the scientific research is the development, improvement and implementation of information technologies for a comprehensive assessment of the intensity and nature of anthropogenic pressure on urban (urbanized) water resources by contact and remote methods to improve the efficiency of the environmental management system and the environmental safety of the water fund of cities. The tasks for conducting research carried out using technologies for remote sensing of the Earth from space (ERS), specialized...

Here, we report a laboratory experiment performed with the water from the Don river. Our aim was to examine the effect of NH4VO3 in concentrations of 0.5, 5, 25, and 100 ?g/L of Vanadium (V) on the phytoplankton growth indicators in the absence of their growth limitation by Nitrogen (N) and Phosphorus (P), as well as on the metabolism intensity indicators of plankton communities: biochemical oxygen demand (BOD5) and alkaline phosphatase activity (APA). The stimulating effect on the phytoplankton abundance and biom...

Substances of petroleum origin that reach groundwater limit water use and can have irreversible effects on ecosystems interacting with them. Quantitative changes in groundwater and synergistic effects generated by petroleum products on ecosystems can be objectively quantified based on a scenario for the transport of pollutants concentrations through the aquifer. In this sense, with the help of mathematical models, the research estimates the spatial and temporal dimension of a possible accidental pollution by petro...

Water ecosystems of Arctic region are most vulnerable to modern climatic changes, since global biogeochemical processes mostly occur on territories of permafrost zone. This work gives new insights into fundamental research question of how fast organic matter of thawing permafrost can be converted to greenhouse gases which are emitted into the atmosphere (for example, CH4). We aimed to identify microbial response and associated release of CH4 from Arctic lakes in response to temperature increase. We investigated la...

The paper studies theoretical and experimental issues of improving scour protection facilities of oil trunk line underwater passages. External influences on the stability of oil trunk line underwater passages were analyzed. Based on the analysis results, the impact of hydraulic processes on riverbed deformations in the underwater passage of the Surgut-Polotsk oil trunk line was evaluated. Also automated calculations of hydraulic and riverbed effects of the bottom soil scour in the Mathcad application environment w...

Water quality was investigated in Lake Matita, part of the Danube Delta Biosphere Reserve, Romania, to assess the overall status of the freshwater ecosystem, in accordance with the EU Water Framework Directive (WFD ? 2000/60/EC), which addresses all surface waters i.e., rivers, lakes, transitional waters and coastal waters in the EU. From this perspective, a specific physical and chemical analysis of surface water samples was performed, collected in different sectors of the lake, during the summer of June 2020. Se...

Applicability of rainfall-runoff models to the river conditions in temperate climate is tested. Different deterministic models were examined with distributed and semi-distributed parameters. Finally, two models have been selected from US Army Corps of Engineers - Hydrologic Engineering Centre: HEC-GeoHydrological Modeling System (HEC-GeoHMS) and HEC-Hydrological Modeling System (HEC-HMS). Hydrological study for selected Bulgarian watershed is presented. The populated and urbanized area of Yantra River basin is con...

This article presents the results of studies of the hydrodynamical and sedimentological conditions of the Sulina Channel, the middle distributary of the Danube within its delta. One field campaign (at low waters) in September 2019 was conducted to analyse the geometry, the sediment composition and hydraulic conditions of the channel. During the field campaign, the measured water mean velocity was from v = 0.01?0.54 m.s-1 for a water discharge (measured upstream, at the bifurcation, knot Ceatal St. George) of 698 m...

The incidence of extreme rainfall has increased in recent decades. This negative impact of climate change also calls attention to when dealing with the recovery and reconstruction of sewer networks. Slovak cities have built a combined sewer network, which in the event of heavy rainfall, is not able to fulfill their primary function. The pipes are not able to carry the large volume of mixed wastewater, and network overload occurs. This paper focuses on the assessment of individual collectors of the sewerage network...

The updating of the used inflow data to the reservoirs from Annex 1 of the Water Act has been developed for the needs of the Ministry of Environment and Water (MoEW) and for the annual schedules of their water use. Monthly inflow with a certain probability of exceedance (PE - 50%, 75%, 95%) were estimated. The results of the development are uploaded to the MoEW website(https://www.moew.government.bg).In the report are presented and new unpublished results of the annual security assessments - annually inflows with ...

Measured sediment concentration records are important information to support water management activities. However, for various reasons, these time series could be incomplete. This paper contains options for modelling the concentrations of suspended sediments when unmeasured periods occurs. Using of various modelling strategies for is discussed and some statistical and machine learning methods are selected for this task. The results show a significant increase in the accuracy of modelling the concentration of suspe...

Increased pollution of water resources leads to a deterioration of surface water and groundwater quality, and it initiates the application of various methods for water treatment. Adsorption on a suitable adsorption material is the most frequently used methods in water treatment. Adsorption processes are based on the adsorption of contaminants on the surface of an adsorption material. The molecules of the contaminant pass from the water environment to the solid adsorbent. Oxides, oxyhydroxides and hydroxide contain...

The territory of the North-Western Pryazovie is adjacent to the northern coast of the Sea of Azov. There are 14 rivers flowing through the territory of the North-Western Priazovie with a total length of 944.1 km and a water intake area of 10.613 km2. Territorially, the river network of the Sea of Azov can be divided into two parts: western and eastern, which differ from each other in the structure of the surface, climatic conditions and the nature of the hydrological regime. The rivers of the North-Western Pryazov...

The demographic load on the Volga River beaches in the Cheboksary urban district (Russia) significantly exceeds their maximum demographic capacity. This happens, first of all, due to the ?improper distribution? of holidaymakers between the beaches of the right and left banks of the Volga River. The ?improper distribution? of the holidaymakers is caused by the unjustifiably high cost of time, financial expenses that holidaymakers incur when visiting left-bank beaches. It is necessary either to significantly expand ...

Hydropower plants still hold globally the first position among the renewable resources in the production of electricity. They are one of the most environment-friendly way to generate electricity and thus waterpower is considered as a renewable resource with good prospects. A disadvantage of producing electricity from renewable resources is its problematic storage. Nevertheless, the water sources have a way to store electricity by water accumulation in the reservoir. This principle is used especially by the pumped ...

In the Danube delta, on the Sulina Channel, the morphology and bedforms characteristics have been investigated. 3D bathymetry, flow velocity, and bed sediments data have been acquired, in order to investigate the dynamic of the bedforms, the distribution of the water, and their influence against the river bed. A single observation (in May 2019) was made regarding the geometry, sediment composition and hydraulic conditions under which the dunes grew and decomposed. The investigation focuses here mostly on the geome...

This article is based on the results of studying the dynamics of long-term fluctuations in the flow of spring floods of the Don and Dnieper river basins in the territory of the Belgorod Region in the period 1968?2018. The object of the study are the maximum water discharges during the spring flood on the Tikhaya Sosna river near the town of Alekseevka (right tributary of the Don river) and Vorskla river near the village of Kozinka (left tributary of the Dnieper river). These rivers were chosen as objects of study ...

This report provides the findings of analysis intended to determine the reasons for the hydrogen sulfide formation in anaerobic conditions of urban sewage systems. The studies have shown that the technogenic content of sulphates in urban networks and the presence of organic components in wastewater lead to the formation and release of hydrogen sulfide into the atmosphere. Various methods of hydrogen sulfide removal from wastewater have been analyzed. The authors of the report have developed a complex alumina-ferro...

The methodology of sustainable forecasting of runoff and diagnosing bifurcations of its formation, being considered in the article, allows solving fundamentally new hydrological problems (including problems of engineering hydrology) related to the possibility of obtaining long-term estimates of the probabilistic characteristics of long-term river runoff under the conditions of evolutionary changes in the runoff formation factors (climate and anthropogenic activity on catchments). Currently, these long-term estimat...

The review of methods and devices for measuring of the raindrops sizes is considered in the article. A brief classification of the main groups of methods and devices for measuring of raindrop diameters is proposed. These materials could be useful in the development and selection of methods for analysis the characteristics of natural rains and artificial rains which are created by sprinkler machines. It is noted that all existing methods can be conditionally divided into the following groups: direct, indirect, opti...

This paper describes the IFIM method (Instream Flow Incremental Methodology) for determining the minimum discharge, which, in addition to hydrological parameters, takes hydraulic, morphological and ichthyic parameters into account as well. The basic principle of the method is the relationship between the fish population and its habitat, i.e. that most of the fish species prefer certain combinations of depths, stream velocities and bed materials. If the values for a species living in the section of the river invest...

We studied a scour in a drainage canal of the Cheboksary hydrosystem tailrace on the Volga river. To protect the hydrosystem tailrace from scouring, we proposed flexible stream-guiding grids that are installed in the stream and effectively affect its kinematics in the bottom area. We calculated in MathCad a system of vortices that occur when the flow runs against adjacent plates of a grid. Due to the replacement of flexible elements of a grid with flat plates that divide the flow into separate jets, it became poss...

Danube is part of the Rhine / Meuse - Main - Danube priority axis, being the second longest river in Europe. Danube is an important international river route, flowing through 10 countries: Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine. Most of the Danube, 28.9%, stretches over the territory of Romania. In the rest of the countries where the Danube arrives, they have much lower percentages. It collects most of the Romanian rivers, except some from Dobrogea, that are ca...

The purpose of research is to study the joint influence of climatic and biological factors on materials in the mixing zone of river and seawaters in the mouth area of the Don River. In December 2018, studies began on the dynamics of settling of fouling organisms on experimental plates (aluminum alloys of grades AMg6 and D16 and carbon steels of grades 30HGSA and St3) in full-scale climatic tests in the mixing zone of river and seawaters at two stations (St.1 & St.2) in the mouth area of the Don River. The control ...

Jurisprudence and international cooperation in the field of pollution of international and regional watercourses have registered over time a rapid evolution if we refer to the documents issued by international and regional bodies that against the background of environmental disasters have come together and developed a series of tools legal and international vocation aimed at preventing and limiting the pollution of water resources. At intra-Community level, in order to prevent and limit the pollution of watercours...

This work provides justification of the opinion that over the past historic periods natural resource management did not cause serious damage to the environment. The recent epoch differs from the previous ones in a large set of natural resource management types and inter se in the presence of environmental management systems to transform the landscape sphere. In particular, the article examines the mining complex impact on the structure of natural (landscape; hydro-geological; environmental) resources. The purpose ...

In the Ropazu district at Latvia, a set of dolomite excavation quarries is located. Because the quarries must by drained by pumping out groundwater, depression cones appear in the quarry areas and around them. The research targets were investigation of the interaction between the quarries, evaluation of adverse changes caused by them in the groundwater regimes of the nature reserve wetland area «Lielie Kangari» and in flows of hydrographical network. The research was carried out by applying the hydrogeological mod...

The Danube Delta Biosphere Reserve (DDBR) covers around 580,000 hectares, where the waters of the Danube enter the Black Sea. It is the second largest and the best preserved of Europe?s deltas; its dynamic, relatively wild ecosystem supports a rich diversity of wetland habitats, numerous lakes, ponds and over 330 species of birds and 45 species of freshwater fish [1]. The region has a long history and the DDBR includes a number of Iron Age fortified sites, remnants of Greek and Roman settlements, and early Christi...

Low impact development (LID) facilities are used to reduce the inflow of rainwater into the sewer network. Their use is welcome in highly urbanised areas where they decrease the network overloading during heavy rains. The aim of this paper is the implementation of LID facilities into the sewer network of the residential districts in cities. Subsequently, the assessment of their impact on network congestion at different load conditions will be done.

The paper has been prepared in accordance with the stipulations of the regulations in force issued by the Ministry of Waters, Forests and Environmental Protection of Romania. The objectives of this research were: the study of the physical changes resulting from the implementation of the water supply network, the analysis of potential sources of pollution of the main environmental factors, and the highlighting the impact on biodiversity of National Park ?Cheile Bicazului - Ha?ma??. These were achieved by: study of ...

The river is the consequential landscape ? forming element as it is rinsing and transporting the weakest rocks, scraping the bed and accumulating the sediment. During these processes in the river, diverse ecosystems are forming in various areas that provide habitats for a wide range of plant and animal species. In almost every river there is occurring a natural process as erosion. River erosion assessment should be considered in river management and included in management measures, as erosion can be determining fa...

The Russian Federation proposes to impose limits on use of polyphosphates (tripolyphospahte, phosphate compounds, and phosphor) in synthetic detergents in the Eurasian Economic Union. The primary reason for this proposition to make amendments into the EAEU countries legislation is a possible decrease in quality of natural water objects used as drinking water supply sources. When it comes to phosphor derivatives, this deterioration is caused by eutrophication. Analysis of hydrological and hydrochemical data reveale...

Reservoirs are important hydraulic infrastructure for water use and flood control. Their impact on the hydrological regime of rivers downstream is significant. Accurate and reliable forecasting of flows in the rivers below the reservoirs is very important in cases of extreme meteorological events (heavy rains) for flood mitigation. The evolution of physically based hydrological models in recent years significantly improved the ability to describe and represent the hydrological processes at a basin scale. This pape...

Water resources are vulnerable not only from climate change, but from many other socio-economic drivers of change. According to the Intergovernmental Panel on Climate Change ?Vulnerability is the degree, to which a system is susceptible to, or unable to cope with adverse effects of climate change, including climate variability and extremes?. When a trend towards decreased precipitation and runoff coincides with a trend towards higher water consumption or deteriorated water quality, then the given region or river b...

The article considers the solving the problem arising at the mathematical modeling of hydrological processes, namely, the problem of the number of phase variables taken into account in the model. The number of variables in the model can change depending on the climate. The fractal dimension characterizes required number of variables. In the article the results of applying the established regularity of the influence of the long-term norm of surface air temperature on the fractal dimensionality of the annual runoff ...

The town of Vidin is supplied by underground water sources through shallow and shaft wells of the ?Raney? type on the terrace of the Danube river. The main water source is located near the village of Slanotran, 12 km northeast of Vidin and consists of 4 wells with horizontal drainage rays, type ?Raney?. In recent years, has been operating mainly well 1(R-1), which is able to supply the required quantities of water for the ?Vidin? group. The annual amount of water supplied by ?Slanotran? pump station is about 7300 ...

In the last years, Romania has suffered large-scale flooding with large areas of land affected by floods, causing major infrastructure damage and leaving behind a significant number of deaths. Climate change and the high frequency of dangerous hydrometeorological phenomena manifested by torrential rains of special intensity produce flash-flood on watercourses due to the rapid concentration of leakage on slopes. These phenomena characterize the vast majority of river basins in Galati County. The pilot area chosen f...

The article presents limnological ecosystems environmental status assessment outcomes on the example of the investigated lakes of Ukraine, through the development and implementation of current information technologies. Approaches to the theoretical substantiation and experimental study of establishing the real spatial resolution of the Earth Remote Sensing (ERS) methods in the visible optical spectrum for limnological systems are proposed. The research is based on the use of information potential and the introduct...

Nearly 20 years have passed since the European Community implemented the European Directives on water management. Its main directions are the achievement of good water quality and the implementation of water management principles. In Georgia, this process has been underway already for 3 years. The country's territory is divided into 6 basin areas. One of them is the Rioni River basin, whose area is 13,000 km2 with up to 700 rivers. In addition, there are reservoirs and a system of irrigation canals. In the downstr...

The purpose of this study was to separate and subsequently investigate the lake governance developments within existing surface water resource governance system in Latvia by looking across all the three country administration levels, namely of the national, regional and municipal levels, in order to determine the actual state and main drawbacks of this step-wise developing lake governance system in Latvian. In this study, lake governance was systemized and characterized, taking note of what particular and eventual...