Ukrainian hydrometeorological journal

Methodological approaches to assessing the risks of water resources depletion in the context of climate change (using plain territories of Ukraine as an example)

N. S. Loboda — 2024-09-15

The relevance of the work is determined by the necessity of quantitative assessment of the risks of water resources changes occurring in the early 21st century due to the greenhouse effect and corresponding climate changes. To evaluate climate risks the authors used a probabilistic approach which involves multiplying the indicator of water resource reduction by the probability of such event occurrence. Reduction of water resources caused by warming characterizes their "depletion". The study utilized the results of calculations of the average long-term annual "climate" runoff, determined through the "climate-runoff" model based on meteorological data of the averaged model trajectory of the EURO-CORDEX project for the climate change scenarios RCP4.5 and RCP8.5. The calculation period extends from 2021 to 2050, while the baseline period continues from the beginning of observations until 1989. The comparison of the calculated climatic runoff and the baseline runoff was performed across meteorological stations. The assessment of the changes was carried out by calculating the relative deviation between the baseline and calculated runoff values. The probability of the "depletion" stage for water resources was determined as the ratio of the number of meteorological stations (grid nodes) where changes reached certain magnitudes to the total number of stations considered. The threshold indicators for the degree of depletion of water resources included changes exceeding 10% (statistically significant changes in water resources), 50% (water resources destruction), and 70% (irreversible destruction of water resources). The objective of the study consists in developing criteria for calculating climate risks and establishing the risks of formation of a tense, critical, and catastrophic state of water resources, taking Ukraine as an example. A detailed examination of the intervals of changes in water resources showed that the highest risk of their depletion over the period from 2020 to 2050 will be observed in the range from -20 to -40% (tense state) for the RCP4.5 scenario and from -30 to -60% (tense state) for the RCP8.5 scenario. It was established that the climate risks of depletion and irreversible depletion of water resources for the territory of Ukraine from 2020 to 2050 remain quite small, which is confirmed by the low probability of their occurrence. However, the risk values increase by 1.5 to 2.0 times for the RCP8.5 scenario compared to the RCP4.5 scenario. Additionally, for calculating the climate risks, it was proposed to use a relative area subject to depletion as an indirect indicator of losses (a larger area implies higher costs of restoration). This approach allowed for having more differentiated risk assessments. The developed methodology for assessing the climate risks of water resources depletion in the context of global warming can be applied for various models and countries.

Analysis of the environmental state of the Sarata River in Odesa Region

N. S. Loboda — 2024-09-15

The relevance of the study is dictated by the need to preserve the water resources of southern Ukraine and ensure their good environmental condition. In the context of military operations, Odesa Region plays a key role in providing the country with agricultural products because of significant damage incurred to agricultural lands of Mykolaiv and Kherson Regions in the course of military actions. Hence the role of irrigation and the need to restore and modernize irrigation systems are growing. One of fresh water reservoirs of Odesa Region is Sasyk reservoir (artificially created as part of the estuary) which accumulates fresh water supplied from the Danube. The Kogylnyk and the Sarata rivers flow into the northern part of the reservoir and can worsen its hydroecological condition. The subject of the study: pollution of the rivers across North-Western Black Sea Coast by chemicals. The object of the study: the environmental state of the Sarata River. The study is aimed at assessing the environmental state and environmental risks of chemical pollution of the Sarata River. The water quality assessment was performed based on a modified version of water pollution index (WPI). Biogenic substances (ammonium nitrogen, nitrite nitrogen, nitrate nitrogen) were identified as the main pollutants. The content of chlorides and sulfates is also significant. The assessment of the pollution risks by biogenic substances is based on calculations of the statistical probit function. The source materials of the research include hydrochemical observations made by the State Agency of Water Resources of Ukraine for the period from 2007 to 2023 in the upper reaches of the Sarata River - village of Miniailivka (94 km from the mouth, near the border with Moldova) and in the lower reaches of the Sarata River - village of Bilolissya (14.3 km from the mouth). The analysis of probability of exceeding the MPC for fishery use indicated that, in terms of nitrite ions and nitrate ions, such probability is higher in the upper basin than in the lower one. According to other indicators, the probability of exceeding the MPC by pollutants is either almost the same or slightly increased in the lower reaches. The assessment of water quality according to the modified WPI (dissolved oxygen, BOD₅, ammonium, nitrite and nitrate ions, phosphates) showed that the water quality in the Sarata River mainly belongs to the "moderately polluted" and "polluted" classes. According to the environmental risk indicators, it was established that the possibility of a "high" risk of contamination by biogenic substances does prevail. Its probability is 52.9% for the upper reaches and 60% for the lower reaches. The "high" level of class IV pollution (ER=0.60-0.79) corresponds to an "unsatisfactory" environmental condition. The probability of achieving the class of a "good" environmental condition (class II, ER=0.20-0.39) is quite small: 17.6% in the upper reaches and only 6.67% in the lower reaches. Thus, the Sarata River belongs to such rivers, the natural properties of which underwent significant changes as a result of sewage delivery from "Sarata Komunservis" utility enterprise, settlement of Sarata. Contaminated waters are unsuitable for drinking, household and sports purposes, as well as for fish farming. The quality of the Sarata River's water has a negative impact on the environmental state of Sasyk reservoir.

Changes in the air temperature regime across the Dniester River basin at the beginning of the 21st century

N. S. Loboda — 2024-09-15

The relevance of the chosen topic is based on the goals and objectives of the Water Strategy of Ukraine until 2050 that provides for promotion of studies on the impact of climate change on the water content of Ukrainian rivers. The Dniester River is a transboundary river. It supplies water to Moldova and several regions of Ukraine. Predicting possible changes in the Dniester River's runoff due to global warming will help our society adapt to new climate conditions and take preventive measures. The research of the mountainous part of the watershed is of particular importance, as it is the area of runoff formation. Warming can change contribution of the snow component to the river's feed pattern and affect the total river flow. The object of the study: changes in air temperature due to global warming. The subject of the study: assessment of changes in the temperature regime within the Dniester watershed and impact of such changes on formation of its mountainous part's runoff. The study is aimed at assessing the changes in the air temperature regime within the Dniester River watershed at the beginning of the 21st century and assessing the impact of warming during winter season on formation of mountain rivers' spring floods. The main research methods include the method of difference integral curves and the method of regression analysis. The research materials include average monthly and annual air temperatures at 13 meteorological stations located within the Dniester watershed for the period of 1947-2021. The research indicated that the Dniester watershed is subject to warming. Statistically significant changes in air temperature began in 1988. Fluctuations in average annual air temperatures occur synchronously. Positive statistically significant trends over the entire observation period (1947-2021) were found for average annual air temperatures, average monthly temperatures of both warm and cold periods, and for the winter season. When considering two measurement periods (before 1989 and after), it was found that no statistically significant trends were observed before 1989. They were formed after 1989. It was also discovered that mountainous watersheds of the Ukrainian Carpathians respond to warming by forming negative trends in the fluctuations of average monthly runoff of spring floods.

Mathematical model for managing marine ecosystem risks

V. M. Komorin — 2024-09-15

The article presents the results of the research aimed at developing and verifying a mathematical model for managing the ecosystem risks of marine areas. The main purpose of the research is to create an effective tool for assessing and managing the risks arising from anthropogenic influence, climate change and other natural factors. The proposed model is based on the existing theory of sea ecosystem risks management and takes into account the relationship between natural and anthropogenic factors, condition of marine ecosystems, their vulnerability and ecosystem services.

The model uses mathematical methods, in particular, differential equations, statistical analyses, simulation modeling and network analysis, allowing creation of detailed models that reflect marine ecosystems' dynamics and their response to external influence. Numerous experiments were conducted in order to verify the model. They demonstrate its ability to predict changes in the condition of marine ecosystems under influence of various factors. The results of the research show that the proposed model can be an effective tool for optimizing management strategies, minimizing ecosystem risks and improving sustainability of marine ecosystems.

Practical recommendations developed on the basis of the results of the research include strategies for preventing, minimizing and adapting to potential threats, taking into consideration each region's and ecosystem's specifics. The proposed model helps to optimize management decisions, reducing risks and improving the condition of marine ecosystems affected by anthropogenic impact and climate change. It is a reliable tool for ensuring sustainability and preservation of marine ecosystems. This approach allows for evidence-based risk management that increases sustainability of marine ecosystems and their preservation for future generations.

The model also considers key factors influencing marine ecosystems, including biological diversity, water quality, industrial fisheries, tourism and recreation, and allows evaluation of effectiveness of various management decisions in the context of such factors. The application of this model in ecosystem management practices allows making more informed decisions regarding protection and preservation of marine resources. It contributes to their sustainable development and provision of ecosystem services having critical importance for society.

The impact of the destruction of the Kakhovka reservoir dam on the oceanographic conditions in the north-western part of the Black Sea according to the results of modeling

Yu. S. Tuchkovenko — 2024-09-15

Based on the results of numerical modelling, characteristic features of distribution of transformed and polluted waters of the Dnieper River in the water area of the north-western part of the Black Sea (NWBS) are determined and analyzed. This pollution of the marine environment resulted from the extremely large man-made flood caused by the destruction of the Kakhovka Reservoir dam by the Russian occupation forces in June 2023. Various types of pollutants, which contained in the Kakhovka Reservoir, in the lower Dnieper River and in the bottom sediments, were carried out into the sea by the flood discharge. A significant amount of pollutants was washed into the sea from the flooded areas of the lower Dnieper basin. Special attention is given to changes in oceanographic conditions in the Dnieper-Bug estuary region (DBR) of the Black Sea, which determine the extent of marine pollution. Sea water salinity was used as an indicator of the degree of infiltration of polluted seawater from the estuary into the sea. It was identified that the least transformed river waters with low salinity correspond to high pollution levels. Delft3D-Flow Flexible Mesh hydrodynamic model, developed by Deltares, was used in this study. The simulation was performed for the time period 01 to 30 June 2023.

During the first days after the dam break the desalinated and polluted transitional waters, flowing from the Dnieper-Bug estuary, spread over the entire water column down to 15-20 m depth in the DBR area. In this case, the spreading of transitional waters was atypical, as it usually occurs only within the thin near-surface layer of the sea. By mid-June the flow of transitional water with a salinity of 4-6 ‰ covered the entire water column from surface to bottom near the northern coast of the NWBS and over the Odessa Bank. This was facilitated by the supermassive volumes of transformed Dnieper river waters flowing out over a short period of time due to dam break, as well as by the resulting intense gradient currents and mixing caused by spatial gradients in the velocity of the generated currents. The width of the desalinated water plume and its area in the bottom layer were smaller than in the surface layer. The largest vertical salinity gradients were formed to the south of the Odessa Bank, where salinity was 4-6 ‰ in the surface layer and 14-17 ‰ in the bottom. Dilution of the desalinated water plume in the bottom water layer was much more intensive than in the surface water.

The character of water circulation pattern in the northern part of the NWBS in the first days after the inflow of transient waters from the Dnieper-Bug estuary was determined by the runoff gradient currents, which later were replaced by wind-driven currents in the Odessa area and over the Odessa Bank, and by the meandering flow of gradient density currents further south.

The findings of this study contribute to a better understanding of the impact of the inflow of transformed river waters from the Dnieper-Bug estuary on the variability of oceanographic characteristics and the ecological state of marine waters in the Dnieper-Bug region of the northwestern Black Sea.

Impact of military activities and hostilities on the ecosystem services of the North-Western Black Sea coastal zone

T. Safranov — 2024-09-15

Satisfaction of human needs for living environment and food, as well as level and quality of life, depend on ecosystem services. The article studies the main methodological principles of ecosystem services assessment for the coastal zone of the North-Westen Black Sea region. Reduction of opportunities for using the ecosystem services negatively reflects the growing anthropogenic impact on environmental components due to urbanization processes, development of industry, energy sector, transport, agricultural sector of the economy, etc. and, since February 2022, - due to military activities and hostilities. The research presents the main indicators used to assess the ecosystem services. Prior to the outbreak of hostilities, the environment of Odesa Oblast was subject to the highest anthropogenic pressure across the whole NWBS region. The forecast indicators of anthropogenic pressure on the components of the NWBS's environment for the next 10 years showed that, within Odesa Oblast, there was a trend towards increasing level of anthropogenic pressure for almost all components. As for Mykolaiv Oblast, an increasing load was predicted for air basin and water bodies, and as for Kherson Oblast – for air basin and soil and geological environment. The article considers the groups of ecosystem services and the factors reducing the possibility of their use as a result of ongoing military operations. Affected by military activities and hostilities, the possibilities of using the resource component of the ecosystem services are brought to minimum. Military activities and hostilities practically stopped the recreational and health function within the coastal zone of the NWBS region. The primary task is to determine the needs of local communities in terms of use of ecosystem services, to collect and summarize information on their condition, agree on methods for assessment of services for the NWBS region, and conduct such assessment. It is necessary to identify the ways to transition to the models of natural resource management across the coastal zone of the NWBS region, taking into account the decline in delivery of the ecosystem services due to both anthropogenic load and military activities and hostilities affecting environmental components.

Сharacteristics of demolition waste management in the regions of Ukraine

T. A. Safranov — 2024-09-15

The volume of waste left from war-related destruction amounts to 10-12 million tons per year. Such volume is comparable to the annual volume of municipal solid waste generated in Ukraine. This situation led to formation of unauthorized landfills and complicated the existing problem of industrial, consumer, construction and demolition waste management. Consequently, the issue of destruction waste management became a pressing environmental and socio-economic problem. The objective of this research is to assess the characteristics of destruction waste management in the regions of Ukraine. Destruction waste is generated during construction of new buildings and public structures, as well as during renovation or demolition of existing buildings and structures; including general-use facilities. It is estimated that, before the war, nearly 7 million tons of construction and demolition waste was generated annually, with more than 50% being transported to municipal solid waste landfills. Specialized landfills for its disposal were virtually non-existent in the regions of Ukraine, so this waste, despite its resource value, was taken to municipal solid waste landfills or unauthorized dumps. Some components of construction and demolition waste are toxic. Destruction waste includes parts (fragments) of damaged (destroyed) objects, as well as materials and items that were inside or next to such objects at the time of damage (destruction) and/or during disassembly activities, including those that fully or partially lost their consumer properties and cannot be reused at the place of their origin or discovery. Destruction waste pollutes the environment, so one of the ways to reduce environmental risks is to develop an effective waste management system to stop chaotic processes during disassembly activities. Destruction waste differs from construction and demolition waste by the presence of accompanying hazardous components, complicating the development of a waste management system. The main components of destruction waste should be used as secondary raw materials for construction, production of building materials and other purposes. Provided that appropriate physical-geographic, engineering-geological, hydrogeological, technical, and socio-economic conditions are available, it is advisable to create temporary waste storage sites, with their subsequent use as secondary raw materials in the post-war period for restoration of civil, industrial, and transport infrastructure in the regions of Ukraine.

Agroecological aspects of nutrients absorption by industrial crops in the conditions of Odesa Region

P. S. Nikitin — 2024-09-15

Modern agroindustrial activities that are focused on intensive methods of agricultural production require a deep understanding of the processes occurring in agroecosystems. Odesa Region is characterised by specific agroclimatic conditions and soil cover features making the study of this issue higly relevant. Intensive use of industrial crops requires knowledge about absorption and removal of biogenic elements such as nitrogen, phosphorus, and potassium.

The importance of this research is determined by the need to reveal the dynamics of biogenic elements absorption by industrial crops in the conditions of Odesa Region, taking into account its agroclimatic and soil characteristics. The results of this research are intended to contribute to development of scientifically grounded recommendations for farmers and agricultural enterprises regarding effective management of agroecosystems.

This will not only increase productivity of industrial crops but also ensure environmental sustainability of agricultural practices. Identifying the optimal conditions for absorption and removal of biogenic elements will contribute to improvement of soil fertility and preservation of its productivity in a long-term perspective. The conclusions and recommendations obtained during the research can be used to improve agronomic practices, reduce environmental impact, and increase efficiency of agricultural production.

Considering current trends of agricultural development, it is necessary to pay special attention to optimization of agrotechnical measures allowing reduction of expenses for fertilizers and improvement of their efficiency. Introduction of new technologies is another important aspect to be considered. It will allow more precise determination of plants' nutrient needs and help to provide them with nutrients according to their growth phases. In addition, it is necessary to consider the interaction between different nutrient elements that can affect their availability and plants' ability to assimilate them.

Assessment of suitability of the Dniester River's water for drinking water supply

M. Ye. Romanchuk — 2024-09-15

The Dniester is a transboundary river between Ukraine and the Republic of Moldova. It is the second longest river in Ukraine and the ninth in Europe. From its source to a town of Staryi Sambir, the Dniester flows through the Carpathian Mountains, then across the flat territory of Ukraine and Moldova.

The Dniester Basin extends across seven regions in southwestern Ukraine (Lviv, Ivano-Frankivsk, Ternopil, Khmelnytskyi, Vinnytsia, Chernivtsi and Odesa Regions). A small area of the river in its upper reaches is located in Poland. The basin's shape is a very elongated oval that is curved in the middle, about 700 km long with an average width of 120 km.

As it flows into the Black Sea, the Dniester River forms the Dniester estuary in Odesa region (between Ovidiopol and Bilhorod-Dnistrovskyi districts). The estuary area of the Dniester River is a complex landscape system at the sea-river-land contact.

Drinking water is an important factor determining a person's health. Due to the intensive development of industry, agriculture and utility services, the number of pollutants that enter the environment and worsen the quality of drinking water in Ukraine keeps increasing. This increases the risk of toxic and infectious diseases spread among the population that consumes such low-quality water. That is why solving the problem of drinking water monitoring and assessment of its quality is a pressing task requiring urgent action.

The article examines the quality of water for drinking needs at the water intake site of the Dniester River, a town of Biliaivka, for 2018-2022. Water quality assessment was carried out according to DSTU 4808: 2007 based on average and worst values. The methodology covers 80 indicators and, in accordance with sanitary legislation, is divided into seven separate groups (blocks). According to hygienic standards, the quality of river water is considered suitable for use if it belongs to quality classes 1-3. In this research, the analysis was carried out according to 23 indicators included in three groups, so the assessment is considered as tentative: Group I - organoleptic indicators (chromaticity, turbidity); Group II - general sanitary indicators (dry residue (mineralization), sulfates, chlorides, magnesium, alkalinity, hydrogen index, ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, dissolved oxygen, bichromate oxidation (COD), BSK₅); Group VII – toxicological parameters (total iron, manganese, chromium (VI), zinc, petroleum products, synthetic surface active agents (surfactants), volatile phenols).

It was determined that, according to the average values, the water quality of the Dniester at the water intake site is characterized as "good", which means it has clean water of acceptable quality. As for the worst indicators, the water was assessed as transitional in quality from "good" (clean) to "satisfactory" (slightly polluted).

Environmental factors affecting the mortality of population in Odesa Region

N. V. Hrabko — 2024-09-15

The presented research covers a significant part of the period of the COVID-19 pandemic and studies the role of environmental factors in formation of population mortality from main causes. The main causes of mortality among the population of Odesa Region during the studied period include diseases of circulatory system, COVID-19, neoplasms, external causes, diseases of digestive organs and diseases of respiratory organs. The aforesaid causes constitute 94-95% of all causes of mortality in Odesa Region. However, out of these six classes of diseases, only diseases of circulatory system, COVID-19 and diseases of respiratory organs and some of their nosological forms have simultaneous peaks in mortality, during which mortality of the Odesa Region population from all causes almost doubles. Over time, there is a certain redistribution of frequency of the causes of mortality among the six main causing diseases of the population`s mortality in the region. But this does not explain occurrence of simultaneous peaks in mortality from diseases of circulatory system, COVID-19, and diseases of respiratory organs.

Formation of simultaneous peaks in mortality from non-infectious and infectious diseases cannot be explained by the influence of social or anthropogenic factors. This indicates the need to address a number of environmental factors of natural origin – meteorological, biometeorological and heliocosmic. The study shows the possibility of an existing linear statistical connection between these environmental factors and the mortality of the Odesa Region population from such classes of diseases as diseases of circulatory system, COVID-19 and diseases of respiratory organs, as well as the relevant nosological forms. The results of the correlation analysis between mortality rates from major diseases and the environmental factors studied showed weak correlations between them. It is fully consistent with the World Health Organization's view of the role of environmental conditions in shaping public health.