Processes In Water Bodies Research Articles

STUDYING THE EUTROPHICATION OF LAKES IN VOLYN POLISSYA (ON THE EXAMPLE OF LAKE ZASVITSKE)

Many diverse lakes are a natural phenomenon of Volyn Polissya. They are of great ecological, recreational and economic importance. As a result of intensive economic activity, pollution and other anthropogenic factors, many lakes are subject to eutrophication. Excessive enrichment of water bodies with nutrients causes the rapid development of algae, deterioration of water quality and disruption of ecological balance. Global climate change has also had a significant impact on this process in recent years. Lake Zasvitske was chosen for the study. It is located in the north-west of Rivne Oblast, in the Varash district, south of the village of Mlyn and north-west of Lake Nobel. It is part of the Nobel National Nature Park. The area of the lake is 22 hectares. Is 620 m long, 350 m wide, has a maximum depth of 16 m, an average depth of 12.5 m, a coastline of 1.75 km and a capacity more than 5 million m3. The lake is fed primarily by atmospheric precipitation and groundwater from. The ecological condition of the watershed is favorable, there are no potentially dangerous objects, the lake is surrounded by pine forests to the north, east and south, and there are equipped small beaches on the western and northwestern sides. The lake water is quite clean. Concentrations of pollutants are exceeded only by the indicator of biological oxygen consumption by 28% and zinc content by 3.1 times. The NDVI and NDAI indices were used to assess the eutrophication of the lake. NDVI (Normalized Difference Vegetation Index) is a quantitative indicator of photosynthetically active biomass most often used to assess eutrophication processes in water bodies. The value of the index varies from -1 to 1. Negative values of the NDVI index indicate the presence of water in the form of clouds and snow; values close to zero (-0.1 to 0.1) correspond to areas with no vegetation cover. Values from 0.2 to 0.9 indicate active vegetation (including in water bodies). NDAI (Normalized Difference Algae Index) is used to diagnose the process of algae overgrowth in a water body and determine the stage of this process. NDVI values increase with the beginning of the transition of the average daily temperature through 0°C, with maximum values reached in late July - early August. Subsequently, the values decrease until the onset of frost. For example, on April 1, 2022. NDVI acquires small positive values up to 0.1. By mid-May, the index values rise to 0.1-0.2. In the eastern part of the lake, where hygrophytes are found, it increases to 0.3. By the end of the month, the NDVI values for most of the reservoir drop again to 0. At the end of June, the index values increase to 0.1 and decrease again. In the first decade of July, the water is cleared of algae. The index acquires negative values (up to -1), which corresponds to clean water. In August-September, the index values vary in the range (-0.1; -0.5). The NDAI index allows us to better trace the seasonality of vegetation processes in the lake. In early April, the development of vegetation processes begins from the belt of semi-flooded hygrophytes along the shores of the reservoir, covering the island rise in the north of the lake. In summer, the intensity of vegetation processes increases, reaching a peak in September. Subsequently, the vegetation dies off and the process repeats in a new vegetation cycle. Keywords: lake, lake catchment area, limnosystem, geo-ecological state of the catchment area, lake eutrophication, measures to prevent and reduce lake eutrophication.

Natural Factors of Microplastics Distribution and Migration in Water: A Review

Microplastics are widely present worldwide and are of great concern to scientists and governments due to their toxicity and ability to serve as carriers of other environmental pollutants. The abundance of microplastics in different water bodies varied significantly, mainly attributed to the initial emission concentration of pollutants and the migration ability of pollutants. The migration process of microplastics determines the abundance, fate, and bioavailability of microplastics in water. Previous studies have proved that the physicochemical properties of water bodies and the properties of microplastics themselves are important factors affecting their migration, but the change in external environmental conditions is also one of the main factors controlling the migration of microplastics. In this paper, we focus on the effects of meteorological factors (rainfall, light, and wind) on the distribution and migration of microplastics and conclude that the influence of meteorological factors on microplastics mainly affects the inflow abundance of microplastics, the physical and chemical properties of water, and the dynamics of water. At the same time, we briefly summarized the effects of aquatic organisms, water substrates, and water topography on microplastics. It is believed that aquatic organisms can affect the physical and chemical properties of microplastics through the physical adsorption and in vivo transmission of aquatic plants, through the feeding behavior, swimming, and metabolism of animals, and through the extracellular polymers formed by microorganisms, and can change their original environmental processes in water bodies. A full understanding of the influence and mechanism of external environmental factors on the migration of microplastics is of great theoretical significance for understanding the migration law of microplastics in water and comprehensively assessing the pollution load and safety risk of microplastics in water.

Spatial heterogeneity of the effects of river network patterns on water quality in highly urbanized city

River water quality deterioration is a serious problem in urban water environments. River network patterns affect water quality by influencing the flow, mixing, and other processes of water bodies. However, the effects of urban river network patterns on water quality remain poorly understood, thereby hindering the urban planning and management decision-making process. In this study, the geographically weighted regression (GWR) model was used to explore the spatial heterogeneity of the relationship between river network pattern and water quality. The results showed that the river network has a complex structure, high connectivity, and relatively even distribution and morphology. Important river structure indicators affecting water quality included the water surface ratio (Wp) and multifractal features (∆α, ∆f) while important river connectivity indicators included circuitry (α) and network connectivity (γ). River structure has a more complex effect on water quality than connectivity. This study recommends that the Wp should be increased in agricultural areas and appropriately reduced in urban built-up areas, and the number of river segments and nodes should be controlled within a rational configuration. Our study provides key insights for evaluating and optimizing the river network patterns to improve water quality of urban rivers. In the future, the land use intensity, hydrological processes, and human activities should be coupled with the river network pattern to deepen our understanding of urban river environment.

Harnessing ZnCr2O4/g-C3N4 nanosheet heterojunction for enhanced photocatalytic degradation of rhodamine B and ciprofloxacin

Utilizing semiconductors for photocatalytic processes in water bodies as an approach to environmental remediation has gained considerable attention. Theoretical band position calculations revealed a type-II step-scheme charge flow mechanism for ZnCr2O4/g-C3N4 (ZCr/gCN), emphasizing effective heterojunction formation due to synergies between the materials. A composite of agglomerated nanoparticle ZnCr2O4 (Zinc chromium oxide - ZCr)/g-C3N4 (graphitic carbon nitride - gCN) nanosheets was synthesized using the ultrasonication and leveraging the heterojunction to enhance degradation efficiency and active sites participation. The synthesized sample was characterized by XRD, XPS, FTIR, BET, HRSEM, EDX, HRTEM, EIS PL, and UV–visible spectroscopy. XRD analysis confirmed the successful formation of pure ZnCr2O4, g-C3N4 (gCN), and their composite without any secondary phases. Optical investigations demonstrated a red shift (444–470 nm) in UV–visible spectra as ZnCr2O4 content increased. Morphological assessment via HRSEM unveiled agglomerated nanoparticle and nanosheet structures. FTIR analysis indicated the presence of gCN with the tri-s-triazine breathing mode at 807 cm−1, and the identification of octahedral Zn–O (598.11 cm−1) and tetrahedral Cr–O (447.01 cm−1) metal bonds within the spinel structure of ZnCr2O4. A Surface area of 134.162 m2/g was noticed with a microporous structure of pore radius 1.484 nm. Notably, the 15% ZCr/gCN composite achieved a remarkable 93.94 % (Rhodamine B–RhB) and 74.36 % (Ciprofloxacin - CIP) within 100 and 120 min, surpassing the performance of pure gCN. Improved degradation was attributed to higher charge separation (photo-excited electrons and holes), reducing charge recombination, as supported by photoluminescence and photoelectrochemical analyses. The presence of active species like superoxide during degradation was confirmed through a scavenger test. The stability analysis confirms the sample's stable nature (without secondary phase formation) after degradation. This work underscores the potential of ZnCr2O4 based metal-free compounds intended for effective environmental remediation.

Research of phosphate removal from water on reverse osmotic filters

Eutrophication of natural water bodies caused by an excess of biogenic substances is one of the global environmental problems of modern times. Usually, phosphorus is a limiting biogenic element, the concentration of which determines the intensity of eutrophication processes in water bodies. Therefore, it is important to develop methods aimed at preventing excessive amounts of phosphates from entering the environment. To remove phosphates from water, typically used biological degradation technologies, which usually proceed very slowly and depend on the conditions under which the process takes place. Also, Biogenic elements can be removed by using ion exchange, reverse osmosis, and chemical methods. However, the disposal of concentrated solutions becomes an issue with these methods. Baromembrane purification methods, particularly reverse osmosis, are becoming increasingly important in the field of water treatment and purification and are essential in creating efficient and low-waste complex technologies for water purification from biogenic compounds. The study investigated the processes of removing orthophosphates from distilled and artesian water using a low-pressure reverse osmosis membrane Filmtec TW30-1812-50. The dependence of membrane productivity and selectivity on the concentration of phosphates and the degree of permeate rejection was determined. Was found that residual concentrations of phosphates in the permeate increase with the increase in the degree of permeate rejection. The lowest residual concentrations of phosphates were observed at the initial concentration of up to 10 mg/dm3. The highest residual phosphate concentrations were observed at initial concentrations above 900 mg/dm3. At the same time, the membrane productivity constantly decreased with increasing feed concentration and degree of permeate recovery due to the increased osmotic pressure on the membrane. The selectivity of the membrane was highest at an initial concentration of up to 10 mg/dm3 and slightly decreased at a rejection rate of 20-50% for initial phosphate concentrations of 100-900 mg/dm3. At the maximum degree of permeate rejection (90%), the selectivity of the membrane reached 97-99 % and decreased with an increase in phosphate concentrations, which is due to a change in the pH of the medium, hydrolysis of phosphates, hydration of ions, and concentration polarization. The membrane selectivity for phosphates in solutions in artesian water was slightly lower (95-99 %), which was due to the competing influence of chlorides, sulfates, and bicarbonates, as well as a decrease in the pH of the solution to 7.52-7.67, which promotes the hydrolysis of o-phosphates.

Method for Solving the Problem of Load Movement over the Ice Cover of a Reservoir along a Complex Trajectory

Introduction. The development of the polar regions of the World Ocean contributed to an increased interest in studying wave processes in water bodies with ice cover caused by the action of a mobile load. In most papers of domestic and foreign scientists, the ice sheet was considered as an elastic or viscoelastic plate loaded with a rectilinearly moving vertical force. However, when modeling the impact of vehicles on the ice cover, it is of interest to investigate problems in which the force moves along a more complex trajectory. Therefore, this study aims at developing a method for studying the behavior of the ice cover under the action of a force moving along a trajectory of a complex shape, obeying an arbitrary law of motion.Materials and Methods. A method for solving problems of the action of an arbitrarily moving force on the ice cover of a reservoir of finite depth filled with an inviscid incompressible fluid is proposed. The ice cover was considered as a viscoelastic plate lying on the surface of a liquid in a state of potential flow. A concentrated force moving along an arbitrary closed trajectory and being periodic in time was applied to the upper surface of the plate. Hydrodynamic pressure acted on the lower surface of the plate from the liquid side. Due to the periodicity of the load applied to the plate, an integral time transformation was used to solve differential equations describing the behavior of this system. Further, using traditional methods, formulas were obtained for calculating stresses and displacements in the plate and components of the velocity vector of liquid particles. These formulas were presented in the form of an iterated integral. Numerical methods were used to calculate integrals.Results. Calculations showed that the deflection of the ice cover increased markedly with the growth of speed and tangential acceleration of the load movement. An increase in the relaxation time of ice and a decrease in the radius of the trajectory of the load also caused an increase in deflection. The distribution of the fluid particle velocity vector over the depth of the reservoir was calculated.Discussion and Conclusions. The proposed method has shown its efficiency in solving problems about the impact of a moving load on the ice cover of a reservoir. With its help, the influence of the curvature of the trajectory of motion and the mechanical properties of ice, the kinematic characteristics of the movement of the load on the deflection of the ice cover was investigated. The method simulates the impact of vehicles on the ice cover of a reservoir. The results of its application can be used under the construction of ice roads or airdromes on ice.

GLOBathy, the global lakes bathymetry dataset

Waterbodies (natural lakes and reservoirs) are a critical part of a watershed’s ecological and hydrological balance, and in many cases dictate the downstream river flows either through natural attenuation or through managed controls. Investigating waterbody dynamics relies primarily on understanding their morphology and geophysical characteristics that are primarily defined by bathymetry. Bathymetric conditions define stage-storage relationships and circulation/transport processes in waterbodies. Yet many studies oversimplify these mechanisms due to unavailability of the bathymetric data. We developed a novel GLObal Bathymetric (GLOBathy) dataset of 1.4+ million waterbodies to align with the well-established global dataset, HydroLAKES. GLOBathy uses a GIS-based framework to generate bathymetric maps based on the waterbody maximum depth estimates and HydroLAKES geometric/geophysical attributes of the waterbodies. The maximum depth estimates are validated at 1,503 waterbodies, making use of several observed data sources. We also provide estimations for head-Area-Volume (h-A-V) relationships of the HydroLAKES waterbodies, driven from the bathymetric maps of the GLOBathy dataset. The h-A-V relationships provide essential information for water balance and hydrological studies of global waterbody systems.

ВИЙШОВ З ДРУКУ ПЕРШИЙ В УКРАЇНІ «ГІДРОХІМІЧНИЙ СЛОВНИК» (2022 р.)

The article presents and analyzes the scientific reference publication – “Hydrochemical Dictionary”, published by the professor of the Kiev National Taras Shevchenko University V.K. Khilchevskyi in 2022. Hydrochemistry is a scientific discipline that studies the chemical composition of natural waters (surface, underground and marine) and the patterns of its change depending on chemical, physical and biological processes occurring in the environment and under the influence of anthropogenic factors. Hydrochemistry has its own object of study, a theoretical, methodological and methodological basis, which allows it to develop important scientific and practical issues. It is closely connected with hydrology, geology, oceanology, and hydrobiology. Being formed in the process of formation and further development, hydrochemistry is constantly enriched with new terms and concepts. Yes, since the early 2000s. hydrochemical and hydroecological terminology has been influenced by the Water Framework Directive (WFD) of the European Union due to the deepening of international scientific contacts and the implementation in Ukraine of the provisions of the WFD in regulatory documents. Since an ever wider range of specialists is involved in this area, the issues of unification of hydrochemical terminology are becoming important. This goal is dedicated to the “Hydrochemical Dictionary”, which is the first in Ukraine scientific reference publication of this direction. The Dictionary includes terms widely used in the scientific literature on hydrochemistry, as well as a number of terms in related scientific disciplines related to hydrochemistry (hydrology, geography, hydrogeology, hydrobiology, analytical, organic and physical chemistry, geochemistry, etc.), the EU WFD. The “Hydrochemical Dictionary” contains terms covering the following issues: properties and chemical composition of natural waters; processes of formation of the chemical composition of natural waters; methodology and methods of hydrochemical research and water analysis; processes of pollution and self-purification of water bodies; hydrobiological and microbiological processes in water bodies; water quality and integrated water resources management. The Dictionary contains about 830 terms and concepts listed in the subject index, which makes it easy to find the right terms on the corresponding pages. “Hydrochemical Dictionary” is designed for students of universities specializing in “Earth Sciences” of educational programs of the hydrological profile, studying hydrochemical and hydroecological disciplines; will be useful to specialists in the field of hydrochemistry, hydrology, hydroecology, hydrogeology, geography.

Пигменты в донных отложениях зал. Анива (Охотское море)

The data of spectrophotometric determination of the content of plant pigments in the bottom sediments of Aniva bay (the Sea of Okhotsk) obtained in autumn 2013 are presented. The content of sedimentary pigments is shown to be quantitatively related to the hydrological characteristics of the water column and the typological indicators of bottom sediments. The content of chlorophyll a with phaeopigments in the sediments of the bay is generally characterized by values of the oligotrophic category. The pigment characteristics of the bottom sediments of the bay are represented by the values of indicators that differ significantly from those of functioning plant organisms due to the strong degradation of the pigment fund. The prevalence of the concentration of phaeopigments over chlorophyll a, an increase in the contribution of additional chlorophylls to their total amount, as well as an increase in total carotenoids compared to chlorophyll a were noted. The ecological interpretation of the data obtained on pigments and pigment ratios gives an idea of the mechanism of interaction between production and destruction processes in water bodies, which gives to the pigment characteristics meaning of integral ecosystem indicators.

Estimating nitrogen and phosphorus concentrations in streams and rivers, within a machine learning framework

Nitrogen (N) and Phosphorus (P) are essential nutritional elements for life processes in water bodies. However, in excessive quantities, they may represent a significant source of aquatic pollution. Eutrophication has become a widespread issue rising from a chemical nutrient imbalance and is largely attributed to anthropogenic activities. In view of this phenomenon, we present a new geo-dataset to estimate and map the concentrations of N and P in their various chemical forms at a spatial resolution of 30 arc-second (∼1 km) for the conterminous US. The models were built using Random Forest (RF), a machine learning algorithm that regressed the seasonally measured N and P concentrations collected at 62,495 stations across the US streams for the period of 1994–2018 onto a set of 47 in-house built environmental variables that are available at a near-global extent. The seasonal models were validated through internal and external validation procedures and the predictive powers measured by Pearson Coefficients reached approximately 0.66 on average.

Reproductive potential of yellow water-lily (Nuphar lutea) in the conditions of lake ecosystems

Nuphar lutea (L.) Sm. (Nymphaeaceae Salisb.) belongs to the category of highly active cenose-forming plants in water bodies and water flows. The material for study of morphological peculiarities and seed productivity of the fruits of this species was collected mainly in the lake ecosystems of the Central Part of European Russia and Republic of Belarus. In the study we used biomorphological and ontogenetic approaches. Seed productivity was surveyed by direct count of number of seeds in the fruit. By abundance (in descending order), the significant reliable inter-lake differences in a number of morphological parameters of the fruit fall into the following sequence: number of rays of stigma of fruit (in six pairs of lakes) > length of fruit (in four pairs of lakes) > diameter of the stigma of fruit (in three pairs of lakes) > diameter of fruit (in two pairs of lakes) > length of the neck of the fruit (in one pair of lakes). Intra-regional differences in certain morphological parameters of fruits (by number of rays of stigmas) were most notably manifested only in the Belarus lakes which are similar by trophic status. All the differences in the fruits’ morphology could be due to differences in the habitat by the amount of nutrients in water and soil. The amount of seed productivity of the fruits from N. lutea varies broadly. Analysis of this parameter depending on the character of soils in which the plants grew indicated reliable results only in the case of muddy (296 ± 81) and sandy soils (179 ± 13). We determined that distribution of generative diasporas of N. lutea across large distances is related not only to presence of floating ability in the seeds, but also the “multi-step” process of their release: first – mericarps from fruits, and then seeds from mericarps. In the experimental conditions, most seeds directly sunk to the bed (70%) and the rest continued to float on the surface of the water during a month. Low germination of the seeds of the water-lily in the laboratory conditions (4–6%) with use of different means and terms of dry stratification was due to the fact that they have an organic morphophysiological intermediate type of rest. Having such a mechanism causes portioned and prolonged germination, allowing the species to survive in non-favourable conditions and accumulate generative diaspores in the soil. Despite the fact that the initial stages of ontogenesis in the laboratory and natural conditions have no significant differences, we found polyvariance in their tempo of development. First of all, this is related to different dates of transition of the plant from one age state to another. In the case of N. lutea, one should also note the morphological polyvariance of ontogenesis related to change in morphologic characteristics of plants depending on the water level. The obtained results give a more complete picture of the peculiarities of generative reproduction of N. lutea, necessary for understanding the ecosystem role of this plant and its impact on biological processes in water bodies.

Multi-objective multi-pollutant waste load allocation model for rivers using coupled archived simulated annealing algorithm with QUAL2Kw

Abstract A simulation-optimization approach is a suitable tool in waste load allocation problems when considering competing objectives and complex pollutant fate and transport processes in water bodies. Here, an archived multi-objective simulated annealing (AMOSA) algorithm is developed to determine various decision variables related to multi-pollutant waste load allocation (MPWLA) problems. The developed AMOSA algorithm has been coupled to QUAL2Kw in order to derive optimal MPWLA programs in Gheshlagh River, Kordestan, Iran. Minimizing wastewater treatment plant (WWTP) costs, improving the EquityMeasure, and enhancing water quality index (WQI) of the river have been considered as objective functions of MPWLA problems. The applied WQI integrates various water quality parameters (biochemical oxygen demand (BOD), dissolved oxygen (DO), NH4-N, NO3-N, PO4-P, total suspended solids (TSS), and Coliform) in monitoring stations along the river. Results show in the scenario with the best EquityMeasure, higher pollutant removal rates have been allocated to Sanandaj WWTP effluent and pollutant point source No. 7 (creek of landfill leachate) due to their greater contributions to Gheshlagh River contamination. Owing to high pollutant load effluents and unsuitable background conditions in Gheshlagh River, more specific studies show that the water quality index may not be improved over 0.22, no matter how much cost is incurred or equity is sacrificed.

Mathematical Modelling as the Basis of the Information System for Monitoring the Aquatic Environment

During the project preparation of the construction of the facility, an analysis of the environmental situation at the construction site and adjacent territories, including on water bodies, is carried out. Mathematical modelling of processes in water bodies for monitoring their condition has been performed. Water resources of the region are a complex system of interconnected water bodies that interact with each other and have different characteristics. Analysis of the features of the distribution of pollutants in the aquatic environment of the ecological landscape showed that mathematical modelling should be carried out in three main directions, taking into account the nature of the mass transfer of the substance: diffusion; diffusion-convective; predominantly convective. For each type of mass transfer a mathematical model is created: one-dimensional, two-dimensional or three-dimensional. Under conditions of one-dimensional diffusion, when mass transfer occurs in one predominant direction, two options are considered: 1) diffusion from a point source with a known limited amount of matter; 2) diffusion from a permanently operating source with a known rate of outflow of matter. Both these problems are described by the well-known diffusion equation, but their input and boundary conditions are essentially different. The problem of two-dimensional diffusion was solved for the case when contamination occurs on a certain, rather small part of the boundary of a wide reservoir from a source with constant density. The case of threedimensional spherical diffusion is considered on the example of the solution of the actual problem, when the source of pollution of constant power is at the origin (in the depth of the reservoir). The problem of non-stationary convective diffusion was solved by the example of a flat reservoir with a weak water current, when the simulated region is a wide two-dimensional channel, on the small part of the boundary of which there is a source of a passive impurity. In this case, the known impurity transport equation was used. We used to systematize the potential ecological situation and built the appropriate mathematical models that allowed us to obtain quantitative algorithms for solving the problems of monitoring and developing the components of the information system for calculating the concentrations of pollutants in the water system in the region.

Computer simulation of thermal processes in water bodies under different hydrometeorological conditions

Key to the solution of a wide range of technological and ecological problems is getting comprehensive and reliable estimates of the parameters of temperature fields generated by waste water discharges taking into account a set of technological and hydrometereological parameters. In this work, the problem under consideration is analysed, using as an example the Magnitogorsk Iron and Steel Works (MMK), one of the world’s largest steel producers and a leading Russian metal company. The discharge channels of MMK drain warm water in the Magnitogorsk reservoir of the Ural River.

Оцінка процесів евтрофікації водних об’єктів річки Стрижень

According to the results of hydrological, hydrochemical and hydrobiological studies (May-October 2017) the estimation of eutrophication processes in water bodies of the Stryzhen River within the city of Chernihiv is presented. The seasonal dynamics of abiotic and biotic factors which form the water quality and trophic level of water bodies has been analyzed. It was found that the features of the hydrological regime of the Stryzhen River in 2016–2017 were low water content, the offset of the passage and a decrease in the duration of the spring flood. The volume of spring runoff was very low and reached 65% of the total annual runoff. Due to the moderate and heavy rains the water level rose slightly to 5-10 cm. It was established that at this time the movement of water in the channel sections of the reservoirs was absent. The important hydrodynamic characteristics of the ponds from an environmental point of view are mixing and wind-generated waves which cause horizontal and vertical migration of substances and enhance the self-purification capacity of water in the ponds. In the spring and summer, when forming a direct temperature stratification, the thickness of the surface layer of water which took part in the mixing processes in the first, second and third ponds was 0.5, 1-2 and 1 m, respectively. The thermocline divided the water column vertically into two parts, which differed from each other in temperature values, as well as in dissolved oxygen content and saturation, pH values, concentrations of ammonium nitrogen, nitrate ions and inorganic phosphorus. The surface layer of water was characterized by enough concentration of dissolved oxygen, whereas in the water column below the thermocline its deficiency was observed. In spring and summer there was alkalinization of the water in the surface layer of the ponds, which was caused by displacement of the hydrocarbon-calcium balance as a result of photosynthetic activity of algae. Under anaerobic conditions the concentration of ammonium nitrogen and inorganic phosphorus in the bottom water layer increased to 1.29–9.99 mgN/dm 3 and to 0.39–4.76 mgP/dm 3 respectively, the maximum values of which were observed in the first pond. During studies of the ponds of the Stryzhen River, it was found that phytoplankton was characterized by a rather rich species diversity of algae and high quantitative development rates that reached the level of water “blooming” due to the massive development of blue-green algae in July and October 2017. The species composition of macrozoobenthos in the studied ponds of the Stryzhen River was very poor, in total 35 species were found. The most favorable conditions for the development of benthic organisms were found in the river section above the third pond and below the first pond before the Stryzhen River flows into the Desna River. Bioindication analysis showed that the zoobenthos in the studied ponds was in a depressed state (TBI = 1-2), but in flowing river sites it was in the best conditions (TBI = 8). According to most of the studied indicators, water quality corresponded to categories 2-5, but content of dissolved oxygen and an inorganic phosphorus belonged to category 6-7 environmental water quality classification. According to the trophic index the studied ponds belonged to mesotrophic, but during “blooming” of water - to hypertrophic.

Temperature monitoring along the Rhine River based on airborne thermal infrared remote sensing: estimation ofin situwater temperatures and inflow detection compared to artificial satellite data

Water temperature is an important parameter of water quality. It influences the survival and growth of animal and plant species in river ecosystems. Current in situ measurements do not allow for the spatial coverage that is necessary for continuous monitoring. Hence, the ability of remote sensing temperatures from aerial and artificial satellite datasets to accurately identify and investigate water temperature and inflows is evaluated for a case study of the Upper and Middle Rhine River. Water surface temperatures acquired by an aerial survey and the results of two correction methods were evaluated: the difference to in situ measurements could be reduced to 0.04±0.21°C with a calibration based on in situ measurements and to 0.14±0.33°C based on atmospheric parameters modeled with MODTRAN®5.3.2. Inflows and mixing processes of water bodies with differing temperatures could be identified successfully with the change point analysis method and based on the standard deviation of the distributed longitudinal profile even for smaller dischargers. With the artificial satellite datasets, the ability to detect inflows decreases mainly with the noise of the dataset, also leading to a higher number of false positive change points.

Water Quality Improvement Using Renewable Energies

Abstract To reduce the negative effects of eutrophication processes in water bodies it is necessary to improve water quality by ensuring the necessary oxygen concentration. The paper proposes a new innovative solution for the improvement of lake water quality. The premises for the implementation of the experimental floating platform which will aerate the lake waters will be presented. To give a specific view over the oxygen dispersion into the lake, numerical simulations in CFD software will be presented in different cases. The protection of drinking water resources against pollution is a common task of outstanding importance for the water management and environment protection sectors. To prevent water supply problems arising from the short and medium-term quality deterioration of resources caused by pollution incidents, it is vital to develop methods for monitoring the quality of resources as well as methods for monitoring and predicting serious pollution events to protect water users. In the case of vulnerable drinking water resources, the establishment and maintenance of an early warning monitoring system is important. Emergency treatment technologies are also needed by the waterworks to treat the water for periods when the quality of the water has temporarily deteriorated. Innovative solutions for the improvement of water quality consist in using a floating platform equipped with aeration systems. The equipment used to aerate the lake waters is powered by the area renewable energy (solar, wind). So, this platform can be used in isolated area, where there is no energy supply from the national network.

Application of a Semianalytical Algorithm to Remotely Estimate Diffuse Attenuation Coefficient in Turbid Inland Waters

Remote estimation of the vertically averaged diffuse attenuation coefficient over a water layer Kd(λ) is of great importance in understanding and modeling the physical, chemical, and biological processes in water bodies. A semianalytical algorithm was previously proposed to remotely estimate Kd( λ) based on the retrieval of the total absorption and backscattering coefficients ( a and bb ). The algorithm has been effectively applied to clear and slightly turbid oceanic waters, but its applicability in turbid inland waters is still unknown. In this study, the relationship between a and bb on the one hand with Kd(λ) used in the semianalytical algorithm was first validated by the measured a and bb. Second, the semianalytical algorithm was combined with the so-called QAA_Turbid (quasi-analytical algorithm for turbid waters) to remotely estimate Kd(λ) for highly turbid waters. We tested the performance of the combined algorithm at wavelengths of 443, 556, and 669 nm by using a data set collected from a turbid lake in Japan. The validation results demonstrated that it could estimate Kd(λ) (ranging from 1.94 to 9.47 m-1) with root-mean-square error and relative error values of 0.17 and 12.96%, respectively. These results indicate the great potential of the semianalytical algorithm to accurately monitor the spectra of Kd(λ) for turbid inland waters from satellite observations.

Modelling photochemical transformation of emerging organic pollutants in surface waters: effect of water level fluctuations following outflow or evaporation, relevant to arid and semi-arid environments

Water bodies located in arid and semi-arid environments undergo important fluctuations of the water level, and water loss in the dry season may occur through phenomena such as outflow and evaporation. Water scarcity often exacerbates the impact of pollution, because harmful compounds can reach very high concentration values in the presence of relatively low water volumes. Among self-cleansing (depollution) processes of water bodies, photochemical reactions are expected to play an important role in pollutant attenuation, although sometimes they yield harmful intermediates. In this work, the effects of water-level fluctuations on photochemical reactions were studied by means of a modelling approach. The model applies to well-mixed water bodies, such as the shallow ones that are more likely to undergo fluctuations of the water level. We investigated how water outflow and evaporation (as well as a mixed scenario) might modify the steady-state concentrations of the most important photoreactive transients (•OH, CO3–•, 1O2 and triplet states of chromophoric dissolved organic matter, 3CDOM*). Under the same conditions, the possible phototransformation of emerging pollutants such as carbamazepine, ibuprofen, 2,4-dichloro-6-nitrophenol and 2,4-dinitrophenol was also assessed. It is shown that water loss would generally enhance photochemical reactions, but to a variable extent depending on the actual pathway. Outflow would favour all photoprocesses, and particularly those involving •OH and CO3–•. Conversely, evaporation would enhance reaction with 1O2 and 3CDOM* while having practically no effect on •OH, CO3–• and direct photolysis. Enhancement of photochemical self-cleansing of water bodies would partially reduce the pollution impact, but in some cases harmful compounds may be generated.

Planning the Optimal Operation of a Multioutlet Water Reservoir with Water Quality and Quantity Targets

The integration of quality and quantity issues in the management of water resources systems is key to meet society’s long-term needs for freshwater while maintaining essential ecological services and economic benefits. Current water management practices are mostly targeted towards quantitative uses, and quality is usually addressed separately as an independent problem. One of the reasons for the lack of integration lies in the inadequacy of optimization techniques nowadays available to cope with the large, distributed, simulation models adopted to characterize the coupled ecological and biochemical processes in water bodies. In this paper we propose a novel approach based on the conjunctive use of a batch-mode Reinforcement Learning algorithm and a one-dimensional (1D) coupled hydrodynamic-ecological model to design the optimal operation of a multipurpose water reservoir accounting for both quantity and quality targets. We consider up to five operating objectives, including both in-reservoir and downstream water quality parameters, and design efficient operating policies conditioned upon not only the current storage but also water characteristics, such as temperature and total suspended solids at different depths. The approach is applied to a real world case study in Japan consisting of a water reservoir, Tono Dam, equipped with a selective withdrawal structure and used for flood protection, irrigation and recreational purposes. Results show that a potential control over in-reservoir and downstream water quality can be gained without impairing the hydraulic capacity of the reservoir by effectively exploiting—through the operating policy—the operational flexibility provided by the selective withdrawal structures.