Dnieper Cascade Research Articles

The impact of reservoirs on the soils of adjacent areas: overview of global and local aspects

AbstractThis study aims to analyze the impact of reservoirs on the soils of surrounding areas to elucidate potential ecological consequences. To achieve this goal, a territorial analysis of the soil surrounding such reservoirs as the Kyiv, Kaniv, Kremenchuk, and Kakhovka, which constitute the Dnieper Cascade of Reservoirs, was conducted. The study found that the average soil pH changes in reservoirs range from 6.0 to 7.5, while nitrogen and phosphorus content in the soil varies from 0.2% to 1.5% and from 0.1% to 0.5%, respectively. Average changes in the content of humic substances and fulvic acids in the reservoirs range from 1.0 to 3.5 and from 0.2 to 1.5 mg/L, respectively. Furthermore, it was found that the creation of large reservoirs on the Dnieper River is accompanied by significant consequences for shoreline soils. The geomorphological study of the reservoirs within the Dnieper Cascade revealed their diversity in terms of shoreline types. Some have more erodible shores, indicating vulnerability to erosion, as observed in the Kakhovka Reservoir, while others have more neutral shores less susceptible to erosion, such as the Kremenchuk Reservoir. The distribution of humic substances in the reservoirs of the Dnieper Cascade is determined by the hydrological structure and water inflows, with the highest concentrations in the upper regions. Decreased flow velocity in the lower part of the cascade leads to the deposition of humic substances in bottom sediments. The threat to ecological systems is exacerbated by incidents such as the catastrophe at the Kakhovka Hydroelectric Power Station in 2023, which triggered a serious ecological crisis with a wide range of consequences. Consequently, the application of a comprehensive approach to water resource management and environmental protection becomes crucial. This entails meticulous planning of construction, implementation of ecological technologies, and engaging the public in the water resource management process.

ОГЛЯД РЕЗУЛЬТАТІВ ДОСЛІДЖЕНЬ ЗАБРУДНЕННЯ КАХОВСЬКОГО ВОДОСХОВИЩА ЦЕЗІЄМ-137 І СТРОНЦІЄМ-90, ЯКІ ПРОВОДИЛИСЬ ПІСЛЯ АВАРІЇ НА ЧОРНОБИЛЬСЬКІЙ АЕС (1986-1921 РР.)

The available data on the state of radioactive contamination of water and bottom sediments of the Kakhovka Reservoir were analyzed in order to assess the possible deterioration of the quality of the environment based on the indicators of radioactive contamination in the zone of influence of the emergency discharge of water due to destruction of the Kakhovka NPP dam by the Russian military. Contamination of the Kakhovka Reservoir with 137Cs occurred mainly through the fallouts of this radionuclide with aerosols on the water surface in May 1986. A much smaller part of this radionuclide transported by water runoff directly from the headwaters of the Dnieper basin. Strontium-90 entered the reservoir exclusively by water pathway starting from October 1986. The steady trends of decreasing activity of both radionuclides in water has been observed since 1987. Approximately to 1996 137Cs activity concentrations had decreased to pre-accident level, 90Sr activity demonstrated a slow decrease and by 2022 remained slightly higher than pre-accidental level. The average levels of contamination of the Kakhovka reservoir bottom with 137Cs and 90Sr turned out to be the lowest compared to the other reservoirs of the Dnieper cascade. It was shown that in 1994 137Cs activity levels were 0.06 Ci/km2(2,2 kBq/m2) on 80% of the bottom surface (submerged former floodplain of the Dnieper) and were lower than on the territory adjacent to the reservoir. In the areas of silt accumulation (former channel of the Dnieper) 137Cs activity was on average three times higher. Balance calculations based on the data of radiation monitoring of water showed that the amount of 137Cs activity in the bottom sediments in the period 1987-2022 halved due to natural radioactive decay, the amount of 90Sr activity decreased by approximately 20%, since activity losses due to natural radioactive decay were partially compensated by the constant supply of this radionuclide with water runoff from the contaminated part of the catchment. After a catastrophic water leak from the reservoir, the Dnieper floodplain had exposed. According to the calculations, the average density of soil contamination of the ехposed areas with 137Cs does not exceed 0.03 Ci/km2 (1,1 kBq/m2), with 90Sr – less than 0.1 Ci/km2 (3,7 kBq/m2). Silt deposits of the former Dnieper channel, which had an increased level of 137Cs contamination, were re-suspended, probably, and carried out into the Dnipro-Bug estuary and further into the Black Sea. However, according to our assumptions, this should not have a negative effect on the radioecological state of the sea, because the 137Cs activity concentrations in the water of north-western part of the Black Sea were always 20-30 times higher than in the Dnieper water.

Cumacea (Crustacea) in the Dnieper River and Its Reservoirs: Species Composition, Invasions, and Ecology

The spread of crustaceans of the order Cumacea in the Dnieper reservoirs is analyzed in the paper. It is thought that these crustaceans could get into the newly formed reservoirs along with the introduced Gammaridae, Mysidae, and Mollusca. In all reservoirs of the Dnieper cascade, except for the Kyiv Reservoir, where they have not been found till now, 4-5 species of Cumacea have been registered. <i>Pterocuma pectinata</i> (Sow.) dominates in terms of the quantitative indices of its development. During the period of investigations, the numbers and biomass of Cumacea accounted for respectively 25-131 specimens/m<sup>2</sup> and 0.06-0.13 g/m<sup>2</sup>. The highest quantitative indices of Cumacea development were observed at the depths of 2-7 m on sands and silted sands.

ЧАСОВА ОЦІНКА ВОДНОГО РЕЖИМУ ТА РУСЛОВИХ ПРОЦЕСІВ В НИЖНЬОМУ Б’ЄФІ КАНІВСЬКОЇ ГЕС

After the construction of the cascade of reservoirs on the Dnieper River, the over-regulation of water runoff caused significant changes in its water regime. In particular, this applies to the Kaniv Hydroelectric power station (HPP), which was the last to be built in the cascade. In addition, the rivers of Ukraine have a low-water phase of the water regime, which leads to a decrease in their runoff. This, in turn, affects the dynamics of channel formation processes. That is why the current assessment of water regime and channel processes in the lower reaches of the Kaniv HPP is important, because they depend on effective water management activities, operation of reservoirs throughout the Dnieper cascade. The dependence of water inflow to Kaniv HPP on discharges from Kyiv HPP and water runoff of the Desna River has been established. The paper analyzes the current changes in the water regime in the lower reaches of the Kaniv HPP and identifies the main factors of runoff formation in the study area. Hydrological information for 45 years (1977 – 2021) is taken as a basis for research of the regime of daily levels and water consumption in the lower reaches of the Kaniv HPP With the help of statistical analysis, the tendencies to decrease the levels and change of water consumption after the construction of Kaniv HPP were determined. According to the difference integral curves, the cyclicity of water runoff in the lower reaches of the Kaniv HPP was studied and the water phases for average, minimum and maximum water consumption were identified. Graphs of empirical curves of daily supply levels and water consumption are constructed. To obtain the closest approximation of the empirical estimate of the probability of exceeding its analytical value, taking into account the variability of variable random variables of the variational series, the formula of Kritsky and Menkel was used. Water flow curves are constructed and changes in subsidence and rising water levels over different time periods are determined. Significant changes in water content and its impact on the processes of channel formation in the lower reaches of the Kaniv HPP were shown by graphs of relationships between levels and costs for 45 years of its operation. For further calculations, 15 representative curves were selected. The process of channel formation is multifactorial, which mainly depends on natural and anthropogenic factors of channel processes. The calculation of channel formation costs was carried out according to the method of M.I. Makkaveeva and supplemented by O.G. Obodovskyi and set their time dynamics.

Nutrients in the Water of the Reservoirs of the Dnieper Cascade after the Dnieper River Regulation

Nutrients in the Water of the Reservoirs of the Dnieper Cascade after the Dnieper River Regulation

Organic Matter in the Water of the Reservoirs of the Dnieper Cascade after the Dnieper River Regulation

Organic Matter in the Water of the Reservoirs of the Dnieper Cascade after the Dnieper River Regulation

Основні особливості переформування берегів Канівського водосховища

Reservoirs provide an electricity generation, promote the development of water transport, municipal and industrial water supply, irrigation, fisheries, recreation and other economic and social needs. However, calls are increasingly being made to limit the creation of new artificial reservoirs and even to destroy existing ones. The reason for this is the significant and very real negative environmental consequences of their creation and functioning – flooding of large areas of valuable land in river valleys, relocation of large numbers of people to new areas, flooding of low and erosion of high banks of reservoirs, deterioration of river water quality due to stagnation and "blooming” and many others. The aim of this work is to analyze the peculiarities of reforming the shores of the Kaniv Reservoir under the impact of hydrological and morphological processes, measures for the coast protection from erosion, deepening the channel and alluvium of new lands by dredging (mainly in the upper part of the reservoir) are considered. The study of this problem in the reservoirs of the Dnieper cascade, including Kaniv, we started from 1993-1997. Therefore, research methods have changed significantly at different stages. Standard methods of soil science were used to study the impact of the reservoir on the coastal soils, primarily on flooding, waterlogging and soil erosion. Since 2010, more detailed terresrial and water expeditionary routes (land) studies have been started to study the overgrowth of the reservoir with hydrophytic and hygrophytic vegetation with the formation of hydromorphic soils on the islands of the reservoir and its coast. Remote sensing methods of the Earth for analyzing the series of space images Landsat-2, 4-5, 7 and 8 were used to study the temporal and spatial changes of landscapes, as well as geospatial positioning of observation points by GARMIN GPS receiver. The important role of the dams construction and pumping stations to protect the low shores of the reservoir from flooding was noted, which, however, created significant problems in the operation of the facility due to rising electricity prices. Attention is paid to the ecological consequences of the new alluvial lands development within the reservoir water area, in particular to “blooming” and deterioration of water quality, as well as to the limitation of the ability to pass extreme floods and the threat of adjacent territories submergence. The nature of erosion and abrasion of the high right bank was studied with the use of a quadcopter, mainly in the area from the village of Rzhishchiv to the village of Trakhtemiriv. The role of marl clays in weakening the abrasion of shores is emphasized and their vulnerability to destruction is shown. The role and development of ravines on the coast and their participation in the fragmentary formation of hydromorphic landscapes along steep cliffs are noted. On the low left bank there is a reformation of the shores in the area from the village of Kyiliv to the Rzhyshchiv military range, where large areas are set aside for fisheries, hunting and recreational activities, as a result of which the wetlands are reduced. The uncertainty of the problem of pumping the water of the Trubizh River into the reservoir to protect the floodplain lands from submergence is emphasized. It is not recommended to use “Raketa” ships for water transport in this reservoir due to their negative impact on shoreline abrasion.

ОЦІНКА СТАНУ ЕКОЛОГІЧНОЇ БЕЗПЕКИ АКВАТОРІЇ КРЕМЕНЧУЦЬКОГО ВОДОСХОВИЩА ЗАДЛЯ ЗБЕРЕЖЕННЯ ЛАНДШАФТНО-БІОЛОГІЧНОГО РІЗНОМАНІТТЯ В УМОВАХ ЗМІН КЛІМАТУ

Purpose. The problem of preserving the landscape-biological diversity and ecological safety of fresh waters of the reservoirs of the Dnieper cascade is quite relevant due to its growing deficit in the face of climate change. In reservoirs, the coastline is eroding, causing changes in natural landscapes. Almost everywhere, fresh water pollution is growing and becoming more diverse, as a result of which water becomes unfit not only for drinking or the existence of aquatic organisms, but also for technical purposes. When determining the need for water, it is also important to take into account the own needs of aquatic ecosystems in the water quantity and quality. Fresh water is the most important component of nature with a high rate of biodiversity. It is a medium-higher habitat for many species of living organisms, both aquatic and semi-aquatic, providing purity and self-restoration of surface water quality. Fresh water ecosystems are closely linked to terrestrial ecosystems by thousands of different connections that ensure balance in nature. Therefore, biodiversity conservation is important. Methodology. The research was performed using phytoindication, the method of determining the anatomical and morphological changes of plant indicators. Results. The state of ecological safety of surface waters was assessed using indicators of anatomical and morphological changes of indicator plants, which allow drawing conclusions about the resistance of the ecosystem to harmful factors, as well as the need for additional, more accurate physicochemical studies. The object of the research is the Kremenchuk reservoir, the largest among the reservoirs of the Dnieper cascade. The ecological danger formed in it extends both to the coastal part of the water area and reaches the Black Sea. It is the need for additional physical and chemical tests to accurately identify sources of impact on the water of the Kremenchuk reservoir near the Svitlovodsk and further development of measures to ensure the ecological safety. Originality. For the first time is conducted a study of the ecological safety of the Kremenchuk Reservoir waters by the phytoindication method. According to this study, is demonstrated the effectiveness and simplicity of environmental monitoring using bioindication methods. Practical value. According to this study, we demonstrate the effectiveness and simplicity of environmental monitoring using phytoindication methods. References 14, tables 1, figures 3.

Hydrotechnical construction, water engineering and water technologies: some modern issues and training of professionals

The article considers modern problems and problems that currently exist in hydraulic engineering and hydropower, problems of land and water resources. And also problems of training of experts. able to solve these problems
 Recently, the problems caused by existing large hydraulic structures are increasingly mentioned. The main problem is that the nodes of hydraulic structures often form artificial reservoirs of a large plane. It often happens that the depths of reservoirs are insignificant. This situation is very unsatisfactory because the land is used irrationally. which is a valuable resource and has a high cost and can be used effectively for agriculture. Creation of hydraulic structures, complexes of hydraulic structures significantly change the hydrological, biological. salt and thermal regimes of the river on which they are built, the regime of groundwater movement, cause climate change in the surrounding areas. Cascades of hydraulic structures have a special influence. As an example, we can cite the Dnieper cascade of hydroelectric power plants and compare the area of its reservoirs and the amount of electricity generated by its power plants with the world's largest hydroelectric power plants.
 In addition, shallow water bodies cause a significant deterioration in water quality. And since reservoirs are often a source of water supply for settlements and industrial enterprises, this situation is controversial. Intensive construction of hydraulic structures and their complexes took place during the twentieth century, many of them exhausted their resources and needed either reconstruction or decommissioning. The reasons for this state of affairs are the development of technology, the emergence and development of other alternative energy sources for thermal and nuclear power plants, other than hydraulic. Also, since the construction of many buildings, approaches to determining their profitability and efficiency have changed.
 Aspects of training specialists in hydraulic engineering and water engineering, able to solve these problems of the industry today, and those that will face them in the near future are considered. The ability of a competent professional to anticipate the consequences of any action must be an integral part of it. Attention is drawn to the need to apply conceptually new approaches to solving problems of construction of new hydraulic and hydropower facilities, operation and reconstruction of existing facilities.

ВЕЛИКІ І МАЛІ ВОДОСХОВИЩА УКРАЇНИ: РЕГІОНАЛЬНІ ТА БАСЕЙНОВІ ОСОБЛИВОСТІ ПОШИРЕННЯ

The aim of the study was to establish the territorial patterns of the distribution of reservoirs in administrative regions and river basin districts, to identify the role of large, medium and small reservoirs in the balance of river flow regulation in Ukraine. In Ukraine, there are only 1054 reservoirs, among which there are six large reservoirs of the Dnieper cascade and the Dniester reservoir, and all the remaining 99.3% (1047 reservoirs) belong to the middle (M), small (S) and very small (VS) categories. For convenience, we call this group with the abbreviation MSVS-reservoirs. All reservoirs have a total volume of 55.13 km3. Thus, reservoirs regulate 32% of the total river flow of the country, amounting to 170.3 km3 per year. There are two main patterns of territorial distribution of reservoirs: large reservoirs are located on large rivers (Dnieper and Dniester) and are of national importance; MSVS-reservoirs – were created to provide water to industrial regions (for example, Donetsk, Kharkiv) and have regional or local significance. In terms of the volume of accumulated water, Ukraine is a country of large reservoirs. The six reservoirs of the Dnieper cascade contain 79% of the water, in the Dniester – 6%, in the MSVS-reservoirs – 15%. The volume of reservoirs in the Dnieper cascade is 43.71 km3, which is 82% of the average long-term runoff of the Dnieper (53.5 km3 per year). The operation of the Dniester reservoir (3.0 km3), which was created in the transboundary city of Dniester (Ukraine – Moldova), is carried out taking into account the water management interests of the two countries. MSVS-reservoirs are unevenly distributed over the territory of Ukraine. The largest number of them is concentrated in the arid central and southeastern regions of Ukraine, 45% of the total number of MSVS-reservoirs is located in the region of the river basin Dnieper. The largest total values of the total volume and area of MSVS-reservoirs is in the Odesa region due to the Danube lakes, which have been granted the status of reservoirs. In the use of territorial communities in Ukraine, there are 72% of the MSVS-reservoirs, 28% – leased. Among the regions of Ukraine, most of all are rented MSVS-reservoirs in the Transcarpathian region – 78%. In the Zaporizhye region, 56% of the MSVS-reservoirs are leased, in the Ternopil region – 54%. There are leases of MSVS-reservoirs in Ivano-Frankivsk and Lviv regions. Low values of the lease indicator were in the Autonomous Republic of Crimea (4%), in Kherson (7%), Vinnitsa (8%) and Volyn regions (10% each). Among the regions of river basins, there are more leased MSVS-reservoirs in the regions of the river basins. Southern Bug – 35%, Dnieper – 32%. The minimum rental rate was in the region of the Crimean river basin (4%). There is a lease of MSVS-reservoirs in the area of the river basin. Vistula.

Conceptual Provisions Regarding Ecosystem Services of Large Plain Reservoirs by Example of the Dnieper River Cascade, Ukraine

The concept of the ecosystem services (ES) is considered in view of its application to the Dnieper cascade of reservoirs. A new provision on the hierarchical structure of the ES system was proposed. This system includes several levels: river basin, reservoirs' cascade, individual reservoirs, ecosystem subsystems. At each level there is a number of ES, according to the structural and functional characteristics of the ecosystems and metaecosystems. Not all ecosystem functions can be considered as related to the provision of ES (positive services, from the human view point), so along with ES there is a certain number of anti-services (EAS). The ES-EAS system is considered in two variants of the nature management − as the reservoirs cascade in the Dnieper River and as the unregulated river.

DETERMINATION OF NECESSARY CONDITIONS FOR EFFICIENT PURIFICATION OF DRINKING WATER WITH HIGH CHLOROFORM CONTENT BY PLASMA TREATMENT IN AEROSOL

Sustainable development of any country is possible only if the stable supply of its population with drinking water in accordance with their needs, quantity and regulatory quality. This issue is extremely relevant for Ukraine as a low-water state, especially with the further negative impact of climatic and anthropogenic factors on the quality of source water. This is especially true of surface water sources in general and the Dnieper cascade of reservoirs in particular. The regulation of the Dnieper River, global warming and the increase in anthropogenic pressure in the form of a significant (at times) increase in polyphosphates and nitrogen compounds in the effluents entering the Dnieper River provokes catastrophic cyanide growth for four to five months a year. Outdated water treatment technologies are unable to combat this factor and use the only possible technological method for them to combat high organic matter of any genesis – increase the dose of chlorine and coagulants. This usually does not improve the quality of water purification, but leads to the sustainable formation of organochlorine compounds in the process of water purification and transportation. Chloroform is a constant marker of trihalogen methanes and its concentration is determined by water supply laboratories. Accordingly, we investigated the possibilities of oxidation of chloroform by means of complex oxides formed by corona discharge in a water-air medium in the mixing chamber of the ejector. The influence of medium pH on the process of chloroform destruction was studied. It has been experimentally established that even a weakly acidic environment does not allow the efficient oxidation of chloroform and leads to its recombination and even increases its concentration. At the same time, in an alkaline environment, the oxidation process is intense and with lower energy consumption.

Dreissenidae (Mollusca: Bivalvia) in Benthos of the Kiev Reservoir and Factors Influencing Their Distribution

It has been found that mass development of Dreissena polymorpha was observed in the Kiev Reservoir only several years later after its construction in 1965. Dreissena bugensis belonging to typical invaders was registered in this water body six years later. With time D. polymorpha was partially displaced by D. bugensis, especially in deep-water biotopes. The main factors responsible for mass development of Dreissenidae (especially of D. bugensis) in the Kiev Reservoir include the similarity of its hydrochemical indices with those registered in the lower reservoirs of the Dnieper cascade, and also effective ecological and physiological adaptations of these mollusks.

Morphological Variability of Some Species of the Genus Cymbella (Bacillariophyta) from Reservoirs of the Dnieper Cascade (Ukraine)

Morphological Variability of Some Species of the Genus Cymbella (Bacillariophyta) from Reservoirs of the Dnieper Cascade (Ukraine)

PROBABILISTIC RELIABILITY ASSESSMENT OF GATEWAY HEADS BY THE CRITERIA OF STABILITY AGAINST DISPLACEMENT ON THE EXAMPLE OF HYDRO SCHEMES OF THE DNIEPER CASCADE

When calculating and designing modern hydraulic structures, it becomes necessary to assess their reliability and safety based on probabilistic methods. This work further develops the method for assessing reliability of gateway heads by the criteria of stability loss against displacement and overturning.The work considers the random nature of the external loads and impacts, which the gateway heads bear during operation, as well as correlations between them. It also considers the random nature of mechanical properties of the foundation soils and correlations between them. The suggested method allows assessing reliability by the criterion of stability loss against displacement of the gateway heads located both on rock and non-rock foundations. For solving this problem, the method of statistical tests (Monte Carlo method) was applied, which is widely used for assessing probabilistic reliability of complex technical systems.A numerical probabilistic assessment of the risk when the gateway heads on rock and non-rock foundations at hydro schemes of the Dnieper Cascade reach the boundary conditions has been performed. Confidence limits of the probability of losing stability of the gateway heads against displacement are determined; a number of statistical tests required to achieve confident accuracy is determined.Correctness of the obtained results is confirmed by their correspondence with the reliability assessment of the gateway heads of the Dnieper cascade by deterministic analyses using the method of boundary conditions.In the future, the proposed method could be used in probabilistic reliability analyses of hydraulic structures and cascades of hydro schemes, taking into account the correlations between natural factors: hydrological characteristics, wind, and ice, as well as temperature loads and impacts.

СОСТОЯНИЕ ЗАПАСОВ ПРОМЫСЛОВЫХ ГИДРОБИОНТОВ КИЕВСКОГО И КАНЕВСКОГО ВОДОХРАНИЛИЩ

The article analyzes the data of monitoring control catches in the Kiev and Kanev reservoirs, which are a part of the Dnieper cascade of hydroelectric stations. The analysis results allow to assess the current ecological and biological status of the populations of the main fish species in the conditions of anthropogenic impact. The analysis is based on the data of spring control catches carried out by the researchers of Institute of Hydrobiology of National Academy of Science of Ukraine in 2015. It has been stated that generally stocks of valuable commercial fish in the Kiev and Kanev reservoirs can be characterized as stable. Bream and silver bream populations of the Kanev reservoir are in good conditions in terms of reasonable exploitation of commercial core. Conditions for fattening and forming commercial core are estimated as favorable. There has been stated an increase of crucian population due to the low catches and few number of predatory fishes. Dominating commercial species in 2015 in the Kanev reservoir there were roach, bream, crucian, pike perch. There has been registered growing population of cat fish, dynamic recruit-stock of asp, and commercially abundant population of perch. To restore the commercial size of ide population it has been suggested to artificially stock the water reservoir with fish in terms of the state demand. The results of the conducted research help to predict the dynamics of fishing, to scientifically justify the ways of preserving the gene pool of natural fish populations, to take timely measures to limit the catch and further rationalization of the fishery use of the Kiev and Kanev reservoirs in order to develop the concept of stable operation of large fishery reservoirs

PROBABILISTIC RELIABILITY ASSESSMENT OF GRAVITY ABUTMENTS ON ROCK AND NON-ROCK FOUNDATIONS BY THE CRITERIA OF STABILITY AGAINST DISPLACEMENT OF THE GRAVITY ABUTMENTS ON THE EXAMPLE OF HYDRO SCHEMES OF THE DNIEPER CASCADE

When calculating and designing modern hydraulic structures, it becomes necessary to assess their reliability and safety based on probabilistic methods. This work further develops the method for assessing reliability of gravity abutments by the criteria of stability loss against displacement. The work considers the random nature of the external loads and impacts, which the gravity abutments bear during operation, as well as correlations between them. It also considers the random nature of mechanical properties of the foundation soils and correlations between them. For solving this problem, the method of statistical tests (Monte Carlo method) was applied, which is widely used for assessing probabilistic reliability of complex technical systems. In applying the method of statistical tests to assess the reliability of a complex technical system, it is necessary to perform a significant number of statistical tests. This implies determination of internal parameters of the system during each statistical test. A numerical probabilistic assessment of the risk when the gravity abutments on rock and non-rock foundations at hydro schemes of the Dnieper Cascade reach the boundary conditions has been performed. Confidence limits of the probability of losing stability of the gravity abutments against displacement are determined; a number of statistical tests required to achieve confident accuracy is determined. Correctness of the obtained results is confirmed by their correspondence with the reliability assessment of the gravity abutments of the Dnieper cascade by deterministic analyses using the method of boundary conditions. In the future, the proposed method could be used in probabilistic reliability analyses of hydraulic structures and cascades of hydro schemes, taking into account the correlations between natural factors: wind, ice, and hydrological characteristics, as well as temperature loads and impacts.

The Dnieper Cascade as part of International Waterway E40

The Dnieper Cascade as part of International Waterway E40

The Dnieper Cascade as part of International Waterway E40

The Dnieper Cascade as part of International Waterway E40

Methodological features of the assessment of silting processes of artificial reservoirs based on the analogy method

The similarity of artificial reservoirs (AR) is determined by the proximity of their parameters and characteristics. In this regard, the selection of the criteria for analogy is, in fact, the task of multicriteria comparative analysis, which dictates the need, on the one hand, to select the parameters of artificial reservoirs to a decisive degree, determining those characteristics of the reservoirs that reflect their studied properties and, accordingly, the synthesis of the criteria for analogy , providing a solution to the problem of choosing a reservoir-prototype for the analyzed reservoir-analogue. A methodology for estimating the process of siltation of artificial reservoirs (analogues) based on known silt characteristics of a specially selected prototype reservoir is developed. The criterion for choosing a reservoir prototype is a measure of analogy, calculated on the basis of the main characteristics - morphological, hydrological, physico-chemical and biological compared reservoirs. The method is based on the use of sets of complex criteria of various levels of completeness determined by the number of particular criteria included in the complex criterion with the corresponding weight coefficients on the basis of the maximum level of analogy, which is determined by a special measure - the coefficient of nonconformity or the inverse coefficient of analogy. The latter is defined as the ratio of the difference between the criteria for the analogy of the reservoirs being compared to their mean value. A comparative analysis of the values of similarity criteria for reservoirs - analogues (cascade reservoirs) and a reservoir - a prototype and a comparative analysis of the values of the similarity criterion for all combinations of pairs of reservoirs of the Dnieper cascade. On this basis, a matrix of differences in the reservoirs of analogues is constructed, which makes it possible to estimate the possibility of using the similarity method, using as an analogue one of the reservoirs of the cascade, if it satisfies the requirements of analogy.