Open Water Surface Research Articles

МЕЛКОМАСШТАБНОЕ МОДЕЛИРОВАНИЕ ДИНАМИКИ ВОД НА ШЕЛЬФЕ И КОНТИНЕНТАЛЬНОМ СКЛОНЕ В АНТАРКТИКЕ

The use of the Fluidity-ICOM model in a full non-hydrostatic formulation makes it possible to correctly investigate fine-scale water dynamics and water transformations on the Antarctic shelf and continental slope. A possibility of solving problems with high spatial resolution in models is provided by the use of the three-dimensional adaptive unstructured mesh with automatic refinement to given scales. The modernization of the graphical model output made it possible to reliably visualize the detailed development of simulated hydrophysical processes, to obtain numerical estimates of parameters of these processes, and to verify them against unique field observation data. An original three-dimensional numerical experiment was held in the area of polynya with an open water surface on the shelf. In this case, the real salt (buoyancy) flux is specified, which is caused by the in-water ice formation in the polynya and is obtained from the actual atmospheric forcing. As a result, the convective circulation was correctly simulated as a process of formation of dense water on the shelf, which then flows down the shelf and continental slope in the form of discrete density currents. Similarity of the model geometric, dynamic, and hydrophysical characteristics of cascading with the typical ones obtained from the analysis of field observations was found.

A statistical approach on distribution and seasonal habitat use of waterfowl and shorebirds in Çıldır Lake (Ardahan, Türkiye).

Wetlands are crucial habitats for both migrant and resident bird assemblages. The distribution and habitat preferences of birds in aquatic ecosystems are significantly influenced by environmental and ecological factors that critically impact the relevant habitats. In order to reveal the distribution and habitat preferences of the birds, many statistical models and methodologies are employed in ecology and conservation biology. Herein, we investigated the effects of year, season, habitat, and species variables on the distribution and population dynamics of waterfowls and shorebirds associated with the wetland. In this regard, field surveys were carried out in and around Çıldır Lake (Ardahan, Türkiye) between April 2017 and September 2018 to examine the distribution of waterfowls and shorebirds and variations in population sizes. As an experimental design, a stratified random sampling design was used to assess bird fauna in the four dominant habitat types (open water surface, reeds, grasslands, and agricultural areas) in the study area. Accordingly, a total of 51 waterfowl and shorebird species were identified during the study period. Of the identified families, Anatidae (n = 18), Scolopacidae (n = 8), and Ardeidae (n = 8) were the most common families. Considering bird species, common coot Fulica atra and mallard Anas platyrhynchos were the most abundant species. The dependent variable (bird populations) was compared with the independent variables (year, season, habitat, and species). The population in 2018 decreased by 13% in comparison to the population in 2017 (p < 0.05). Once the reed area was considered as the reference, the population density in the water surface habitat increased by 65% (p < 0.001). In relation to seasonal reference, a 65% increase in population growth in spring was recorded in comparison to the growth in fall (p < 0.001). On the other hand, no statistical differences were noted in population growth in winter and summer ((p > 0.05). With respect to the reference species (Anas crecca), critical differences in species fluctuation were observed among species (p < 0.001). Consequently, the findings of the present study suggest that seasonal factor might be of the substantial factors linked to the habitat composition. However, more descriptive and predictive analytical methods are needed beyond classical regression approaches in habitat use and selection studies at bird ecology.

Evaluation of the evapotranspiration rate of lacustrine wetland macrophytes in Lake Tana, Ethiopia

This study quantified the total evapotranspiration (ET) flux of three major types of macrophytes that cover lacustrine fringe wetlands in Lake Tana, Ethiopia during the dry season, April and May, 2022. This study was conducted to understand lacustrine wetland macrophytes' ET rates and provide an important guideline for designing their conservation and restoration plans. To assess ET rates during the peak dry season, three macrophytes of lacustrine wetlands in Lake Tana were chosen: Eichhornia crassipes (water hyacinth), Cyperus papyrus, and Echinochloa stagnina. Three replicate lysimeters for each of the three treatment types (macrophytes) and one control type (open water) were applied to measure ET. To calculate reference evapotranspiration (ETo), FAO's ETo Calculator Version 3.2 was applied. All statistical analyses were carried out using R software. The results of ET rates from wetland macrophytes (9.05mm/day) were considered to be significantly higher than open water evaporation (5.90mm/day). There was a significant difference in mean ET among the macrophytes [F (3, 488) = 194.6, p < 2e-16 ***]. In this study, crop coefficient (Kc1) (1.99 ± 0.65) referenced to FAO Penman–Monteith ETo is greater than Kc2 (1.58 ± 0.59) referenced to open water evaporation (Eow). In terms of wetland macrophyte type, E. crassipes had the maximum mean Kc values (Kc1 = 2.51±0.70 and Kc2 = 2.02±0.67). E. stagnina had the minimum mean Kc values (Kc1 = 1.52±0.32 and Kc2 = 1.19±0.24). Except for open water which strongly correlated with sunshine hours (r = 0.61) and solar radiation (r = 0.60), the correlation among daily ET values and meteorological variables was found to be weak. The result of our research indicated that the presence of floating macrophytes of E. crassipes will increase the ET flux during the dry season more than emergent macrophytes and open water surfaces. Our findings could provide an important guideline for designing conservation and restoration plans for C. papyrus and E. stagnina to reverse the spread of E. crassipes and maintaining lacustrine fringe wetlands for fish breeding ground and sediment control.

TERI advanced oxidation technology (TADOX®) for treatment and rejuvenation of open drains and surface water bodies: making habitats sustainable

Abstract Open drains contain sewage waste and find route to surface water bodies mainly due to the absence of dedicated conveyance of wastewater to centralized wastewater treatment facilities. This poses severe environmental, public health and occupational health hazard and there is an urgent need for onsite treatment of open drains. TADOX® (TERI Advanced Oxidation Technology) from TERI (The Energy and Resources Institute, New Delhi) is an advanced approach treat drains using photocatalysis as an advanced oxidation process. This paper presents a case study of an open drain, which when treated with TADOX® Technology, improved water quality parameters meeting the regulatory norms. The untreated open drain did not meet Class E of the Water Quality Criteria laid down by the regulatory body, and attained Class A Water Quality Criteria after end-to-end treatment within 5 h. TADOX® treatment resulted in the removal of 63.5% chemical oxygen demand, 99% biochemical oxygen demand, 96% phosphate, 61% nitrogen, 3 log reduction in E. coli and 4 log reduction in total coliform values with a doubling in dissolved oxygen levels. Micropollutant load reduction of 93.5% in acetaminophen, 96% in sulfamethoxazole, 96% in ibuprofen and 89% in caffeine was also recorded in the study.

The Three-Phase Contact Potential Difference Modulates the Water Surface Charge

The surface charge of an open water surface is crucial for solvation phenomena and interfacial processes in aqueous systems. However, the magnitude of the charge is controversial, and the physical mechanism of charging remains incompletely understood. Here we identify a previously overlooked physical mechanism determining the surface charge of water. Using accurate charge measurements of water microdrops, we demonstrate that the water surface charge originates from the electrostatic effects in the contact line vicinity of three phases, one of which is water. Our experiments, theory, and simulations provide evidence that a junction of two aqueous interfaces (e.g., liquid-solid and liquid-air) develops a pH-dependent contact potential difference Δϕ due to the longitudinal charge redistribution between two contacting interfaces. This universal static charging mechanism may have implications for the origin of electrical potentials in biological, nanofluidic, and electrochemical systems and helps to predict and control the surface charge of water in various experimental environments.

Evaluation of factors that influence Reoccurrence of Cholera epidemics in Bwera Hospital, Kasese District

Cholera is an acute enteric infection characterised by sudden onset of profuse, painless watery diarrhoea and vomiting. Transmission of the disease is by faecal-oral route and from man to man via faecal contaminated water, ingestion of contaminated foods and drinks, and bottle feeding in infants. Globally, an estimated 1.4 to 4.3 million cholera cases and 28,000 to 142,000 cholera related deaths occur every year and the highest deaths rates occur in developing countries. The aim of this study was to explore the factors influencing reoccurrence of cholera outbreaks in Bwera hospital-Kasese district, Uganda. The study was a descriptive cross-sectional where quantitative strategy was applied on health workers and households within Bwera hospital. The study targeted 73 respondents; random sampling procedure was used. Three broad themes were based on to obtain results namely; sources of water for home use, environmental sanitation and the role of climate change. It emerged that water was mainly collected from unprotected sources using rudimentary methods and it was made safe by boiling. Hand washing was seen as a common practice done though occasionally. Generally solid wastes were poorly managed including human waste and reinforcing reforestation was seen as a remedy to avert effects of climate change. The commonest source of water for home consumption was from open water surfaces mainly rivers/streams. Boiling was seen as one of the commonest methods of making water safe for home consumption but the numbers of house hold that boils water are very few thereby making them prone to infection. Washing hands was the commonest practice especially before eating but still some children do ignore washing of their hands before eating if their caretakers are not around them; however, it was not consistently after visiting latrine. Poor waste disposal was seen present in the communities whereby bushes and river banks were seen as places where human waste is deposited. Keywords: Cholera, Deaths, Households, Bwera hospital, contaminated Water.

Long-Term Changes in Water Body Area Dynamic and Driving Factors in the Middle-Lower Yangtze Plain Based on Multi-Source Remote Sensing Data

The accurate monitoring of long-term spatial and temporal changes in open-surface water bodies offers important guidance for water resource security and management. In the middle and lower reaches of the Yangtze River, the monitoring of water body changes is especially critical due to the dense population and drastic climate change. Due to the complexity of the physical environment in which the water bodies are located, the advantages and disadvantages of various water body detection rules can vary in large-scale areas. In this paper, we use Landsat 5/7/8 data to extract the area of water bodies in the study area and analyze their spatial and temporal trends from 1984 to 2020 using the Google Earth Engine (GEE) platform. We propose an improved water body extraction rule based on an existing multi-indicator water body algorithm that combines impervious surface data and digital elevation model data. In this study, the performance of the improved algorithm was cross-validated using seven other water body indicator algorithms, and the results showed the following: (1) the rule accurately retained information about the water body while minimizing the interference of shadows on the extracted water body. (2) On the annual scale from 1984 to 2020, the open-surface water body dataset extracted using this improved rule showed that the turning point for the area of each water body type was 2011, with an overall decreasing trend in area before 2011 and an increasing trend in area after 2011, with the exception of special years, such as 1998. (3) The driving mechanism analysis showed that, overall, precipitation was positively correlated with the water body area and temperature was negatively correlated with the water body area. Additionally, human activities can have an impact on surface water dynamics. The key influencing factors are diverse for each water body type; it was found that seasonal water bodies were correlated with precipitation and paddy fields and permanent water bodies were correlated with temperature and urban construction. The accurate monitoring of the spatial and temporal dynamics of open-surface water performed in this study can shed light on the sustainable development of water resources and the environment.

Comparison between random forest and support vector machine algorithms for LULC classification

Nowadays, machine learning (ML) algorithms have been widely chosen for classifying satellite images for mapping Earth's surface. Support Vector Machine (SVM) and Random Forest (RF) stand out among these algorithms with their accurate results in the literature. The aim of this study is to analyze the performances of these algorithms on land use and land cover (LULC) classification, especially wetlands which have significant ecological functions. For this purpose, Sentinel-2 satellite image, which is freely provided by European Space Agency (ESA), was used to monitor not only the open surface water body but also around Marmara Lake. The performance evaluation was made with the increasing number of the training dataset. 3 different training datasets having 10, 15, and 20 areas of interest (AOI) per class, respectively were used for the classification of the satellite images acquired in 2015 and 2020. The most accurate results were obtained from the classification with RF algorithm and 20 AOIs. According to obtained results, the change detection analysis of Marmara Lake was investigated for possible reasons. Whereas the water body and wetland have decreased more than 50% between 2015 and 2020, crop sites have increased approximately 50%.

Watershed DOC uptake occurs mostly in lakes in the summer and in rivers in the winter

AbstractRiver networks transport dissolved organic carbon (DOC) from terrestrial uplands to the coastal ocean. The extent to which a reach or lake within a river network uptakes DOC depends on the stream order, the seasonal conditions, and the flow. At the watershed scale, it remains unclear whether DOC uptake is dominated by biological processes such as respiration, or abiotic processes like photomineralization. The partitioning of DOC uptake in lakes vs. rivers is also unclear. In this study, we present a new model that unifies year‐round controls on DOC cycling for an entire river network, including river–lake connectivity, to elucidate the importance of biotic vs. abiotic controls on DOC uptake. We present the Catchment UPtake and Sinks by Season, Order, and Flow for DOC (CUPS‐OF‐DOC) model, which quantifies terrestrial DOC loading, gross primary productivity, and uptake via microbes and photomineralization. The model is applied to the Connecticut River Watershed, and accounts for cascading reach‐ and lake‐scale DOC cycling across 98 scenarios spanning combinations of flows, seasons, and stream orders. We show that riverine DOC uptake is nearly constant with stream order, but the proportion of DOC uptake from photomineralization varies. Photomineralization dominates in rivers in most flow conditions and stream orders, especially in winter, accounting for at least half of whole‐watershed DOC uptake in February across all flows. Whole‐watershed summer DOC uptake occurs mostly via biomineralization in lakes, accounting for 80% of DOC uptake during the growing season, despite accounting for less than 6% of watershed open water surface area.

STUDY AND ANALYSIS OF LAND USE/LAND COVER CHANGES OF JODHPUR CITY AND ITS IMPACTS ON ECONOMY AND ENVIRONMENT (1990-2022)

Urban land use change is a major issue globally. Land cover is a cover that covers any surface and the changes described include urban area land, water body, residential, forest land wasteland, agriculture, and recreation etc. The development of the built-up area separates the city limits.' (PA Khadke &amp; RU Kharat 2017) Land use change plays a major role in the developmental activity of a developing country. Due to the rapid development of urbanization and the dramatically increasing population, fertile agricultural land has been converted into built-up area in relation to the need for housing and the need for infrastructure. The extent of open space and surface water bodies have also been encroached upon. Land use is derived from the human use of land and can be mainly classified into residential, agricultural, commercial use, industrial, etc. Land use and land cover changes are caused by socio-economic and natural factors. The increase in population as well as migration of people from rural to urban is the most important reason for land use change. (P. Sangardas, S. Ishwari, 2019). In the presented research paper, the study and analysis of land use change of Jodhpur city and its impact on economy and environment is to be done.

MATLAB‐based program for computation of open‐channel flow profiles

AbstractIn engineering practice, open channel water surface profile data frequently serve as the scientific foundation for engineering design, flood forecasting, reservoir scheduling, and the calculation of dam‐break flood evolution. Water surface profiles in open channels (WSPOC), Matrix Laboratory (MATLAB)‐based software was developed to help students better learn and improve their interest in surface line theory. According to the flow characteristics, the program is divided into two modules: steady flow and unsteady flow. The steady flow module guides students to master the judgment methods of various gradually varying flow types and can program independently to explore the solution process of the water surface profiles. The unsteady flow module is designed to help students learn finite difference methods in computational fluid dynamics (CFD), and allow students to interact with software in engineering cases to achieve the purpose of effectively integrating theory and practice. This software employs MATLAB graphical user interface(GUI) visualization technology to embed students' autonomous programming in crucial phases and transforms abstract concepts and theories into vivid animation demonstrations using CFD simulation tools. Furthermore, the transformation from theory to practice has been realized by providing a large number of practical engineering examples, which may improve students' ability to solve complex engineering problems. Based on the survey results, the user experience and application effect of the software are satisfactory, and the software's design objective has been achieved.

Historical water body changes using spatio temporal indices - a case study of Dakshina Kannada

The spatiotemporal shift of surface water affects the structure, performance, and development of the ecosystem in Dakshina Kannada as well as its agricultural, economic, and social development. In order to better recognize the long-standing variations in the surface water area in Dakshina Kannada, the study used all available Landsat images, the modified Normalized Difference Water Index (MNDWI), the Enhanced Vegetation Index (EVI), and the Normalized Difference Water Index (NDWI) to map the open-surface water from 2014 to 2020 in the Google Earth Engine (GEE) cloud platform. The study looked at precipitation, temperature, and irrigated land to see how weather variation and anthropological actions affect long-standing surface water changes. The following are the outcomes. (1) The Dakshina Kannada, the extreme, periodic, and yearly average water body area values have all decreased during the last 8 years. In the meantime, the number of extreme, periodic, and lasting waterbodies has been steadily increasing. (2) The maximum water body area influences the variance of surface water area in the Dakshina Kannada, whereas the number of minimum water bodies influences the variation of water body number. (3) The area and number of water bodies are statistically significantly improved by rainfall, which also significantly improves water body area and number. The city's water surface area has changed significantly during the last 8 years, according to this study.

Analysis of Surface Area Fluctuation of the Haramaya Lake using Remotely Sensed Satellite Imagery

Human’s unwise and ineffective exploitation behavior has caused losses of the vital natural resources, soil and water, which will definitely leave the future of the next generation in jeopardy. As a result of human intervention and natural causes most lakes in Ethiopia are shrinking in size while others are showing increase in volume. The intensive exploitation, beyond its regeneration rate, of the Lake Haramaya for water supply and agricultural purposes by the community within and outside its catchment boundary has led to its extinction. Although, some studies have been conducted on land use/land cover dynamics, the focus given to quantification of temporal variability lake surface area and the impact of weather variability on the lake water was inadequate. Hence, this study was conducted with the prime objective of mapping/quantifying the temporal lake surface area fluctuation using time series remote sensing images and investigating the impact of weather/climate variability on the lake. After acquiring Landsat images of the years 1985, 1995, 2003, 2010 and 2016 over the dry Haramaya Lake basin (path/row 166/54), the Modified Normalized Difference Water Index (MNDWI) and the Normalized Difference Vegetation Index (NDVI) were used for enhancing and extracting the open water surface of the lake. All of the enhanced images display a trend of decreasing lake surface water area with an average shrinkage of 23.6% between the year 1985 and up to its disappearance. After 2000 the lake surface area shrinkage was at its maximum which has a direct relation with the occurrence of dry weather as a result ofrelatively higher temperature and low rainfall between the years 2000 to 2003.

Towards building homeostasis through a low-cost biomimetic synthetic foam for building surface cooling and energy saving

Evaporative cooling has been demonstrated as one of the most effective means to reduce a building's energy consumption and achieve homeostasis in buildings without intensive energy demands. In this research, a novel biomimetic inorganic synthetic foam material (BMSF) was developed from reclaimed fly ash cenospheres for building surface cooling. The BMSF material is synthesized from an abundant industrial byproduct (i.e., fly ash cenosphere) through a low-cost and high-yield two-step process. X-ray microtopography (XRM) and scanning electron microscopy (SEM) tests revealed that BMSF has a microstructure that resembles that of the keratinous skin of African elephants and certain desert lizards to enable water to be stored and transported effectively through capillary actions. Experiments were carried out to quantify the evaporative behavior and cooling effect of the material and building roofs equipped with the BMSF panels. The experimental results indicate remarkable cooling performance – i.e., BMSF panels with protruded surfaces have higher evaporation rates than that of open water surface and a surface temperature reduction of 15 °C–25 °C was achieved. Lastly, case studies were carried out on a single-story commercial building in Los Angeles, California, and the results demonstrate that the new evaporative cooling surface material is able to achieve passive cooling for buildings in areas with a mild climate and low relative humidity.

The Effects of Irrigation, Topping, and Interrow Spacing on the Yield and Quality of Hemp (Cannabis sativa L.) Fibers in Temperate Climatic Conditions

The study was aimed at determining the most suitable irrigation schedule program for hemp grown for fibers by using evaporation from the free water surface (Eo), measured by a Class A pan and related crop plant coefficient (Kc). The experiment, carried out in Vojvodina, a northern part of the Republic of Serbia, included three irrigation regimes: I1, I2, and I3 corresponding, respectively, to daily evaporation from an open water surface (Eo), two interrow spacings: RS1 (12.5 cm) and RS2 (25 cm), and topped (T) and not topped (NT) variants. The Kc values used for the calculation of daily evapotranspiration (ETd) were 0.42 for April and May and 1.00 (I1), 0.80 (I2), and 0.60 (I3) from June to the harvest. In addition, the nonirrigated (Io) control variant was also included in the trial. The dioecious fiber hemp variety Marina was used for the trials. Irrigation was carried out by a drip irrigation system and was scheduled based on the water budget method. It started when readily available water (RAW) in the soil layer of 0.4 m was completely depleted by the plants. In the first year of the study, irrigation did not influence the yield of hemp fiber, but in the second one, the best result was achieved for the irrigation variant I1. Interrow spacing did not have a statistically significant effect on both the hemp fiber yield and the quality. The topping of plants significantly decreased the yield of hemp, and it is not recommended when the hemp is cultivated for fibers. The quality of the hemp fibers was not influenced by irrigation, inter-row spacing, and topping. The rate of hemp evapotranspiration was in an interval of 312 mm (ETa) to 520 mm (ETm). The highest values of IWUE and ETWUE in both years and the bark yield in the first year were detected for the I3 irrigation variant, which suggested that the crop plant coefficient (Kc) of 0.6 could be recommended for the correction of Eo values in the calculation of the daily evapotranspiration of hemp (ETd) from June to August. The yield response factor (Ky) with values of 0.22 and 0.60 for the total growing season reveals that, in rainy years, hemp for fiber production could be grown without irrigation in the temperate climate of the Vojvodina region. However, such years are rare. Without doubt, irrigation of fiber hemp is recommended in the mentioned region in order to obtain high yields of good quality product.

Fusion of SAR and Multi-spectral Time Series for Determination of Water Table Depth and Lake Area in Peatlands

Peatlands as natural carbon sinks have a major impact on the climate balance and should therefore be monitored and protected. The hydrology of the peatland serves as an indicator of the carbon storage capacity. Hence, we investigate the question how suitable different remote sensing data are for monitoring the size of open water surface and the water table depth (WTD) of a peatland ecosystem. Furthermore, we examine the potential of combining remote sensing data for this purpose. We use C-band synthetic aperture radar (SAR) data from Sentinel-1 and multi-spectral data from Sentinel-2. The radar backscatter sigma ^0, the normalized difference water index (NDWI) and the modified normalized difference water index (MNDWI) are calculated and used for consideration of the WTD and the lake size. For the measurement of the lake size, we implement and investigate the methods: random forest, adaptive thresholding and an analysis according to the Dempster–Shafer theory. Correlations between WTD and the remote sensing data sigma ^0 as well as NDWI are investigated. When looking at the individual data sets the results of our case study show that the VH polarized sigma ^0 data produces the clearest delineation of the peatland lake. However the adaptive thresholding of the weighted fusion image of sigma ^0-VH, sigma ^0-VV and MNDWI, and the random forest algorithm with all three data sets as input proves to be the most suitable for determining the lake area. The correlation coefficients between sigma ^0/NDWI and WTD vary greatly and lie in ranges of low to moderate correlation.

Changes in extent of open-surface water bodies in China's Yellow River Basin (2000–2020) using Google Earth Engine cloud platform

Dynamics of open surface water is of great significance to understand the impacts of global changes and human activities on water resources. However, long-term changes of open-surface water bodies in the Yellow River Basin have remained poorly characterized. In the study, 26,681 high-quality Landsat images were processed using the Google Earth Engine (GEE) cloud platform to study the long-term changes of the open water bodies in the Yellow River Basin from 2000 to 2020. A percentile-based image synthesis method was used to collect training samples. The multi-index water body extraction rule (MIWER) was proposed to rapidly extract surface water bodies. The results show that (1) The MIWER is suitable for long-term and large-scale surface water mapping based on Landsat images; (2) The average area of permanent and seasonal water in the last 20 years is 9062.59 km 2 and 6918.83 km 2 , respectively, accounting for 56.7% and 43.3% of the total surface water in the Yellow River Basin, respectively; (3) From 2000–2020, both permanent and seasonal water in the whole Yellow River Basin and sub-basins have increased. In general, the total open surface water shows an increasing trend with obvious spatial heterogeneity; (4) The changes of surface water in the Yellow River Basin are related to climate change and intensive human activities, but the influencing factors vary in different regions. The findings of this study demonstrate a novel robust, low-cost water extraction method that satisfies the requirements of terrestrial water inundation mapping and management across the Yellow River Basin. The methodology of this study is expected to be extended to global surface waters, providing valuable information for global surface water resource planning and management.

Long-term detection and spatiotemporal variation analysis of open-surface water bodies in the Yellow River Basin from 1986 to 2020

Accurately investigating long-term information about open-surface water bodies can contribute to water resource protection and management. However, due to the limits of big-data calculations for remote sensing, there has been no specific study on the long-term changes in the water bodies in the Yellow River Basin. Thus, in this study, we developed a new combined extraction rule to build an entire annual-scale open-surface water body dataset for 1986–2020 with excellent effectiveness in eliminating the interference of shadows in the Yellow River Basin using all of the available Landsat images. For the first time, the spatial distribution, change trends, conversion processes, and the heterogeneity of the surface water bodies in the Yellow River Basin were analyzed comprehensively to the best of our knowledge. The extraction results had an overall accuracy of 99.70 % and a kappa coefficient of 0.90, which were validated using 34,073 verification points selected on high-resolution Google Earth images and random Landsat images. The total area of water bodies initially decreased (1986–2000) and then increased (2001−2020); however, only the size of the permanent water bodies increased in most areas, while the size of most of the seasonal water bodies decreased. In regions with human-made water bodies, the non-water areas were substantially converted to seasonal and permanent water bodies; however, in areas with natural water bodies, many permanent and seasonal water bodies were gradually converted to non-water areas. Thus, most of the increases in the water bodies occurred in the form of artificial lakes and reservoirs, while most of the decreases in the water body area occurred in natural wetlands and lakes. The areas of both the permanent and seasonal water bodies were positively correlated with precipitation, but only the area of the seasonal water bodies was negatively correlated with temperature.

Geoinformation analysis of the satellite imagery data in order to assess the changes in radiohydrological conditions over the study territories

The article considers the relevance of the application of a set of terrestrial hydrological, radioecological and modern remote sensing methods in the process of monitoring studies of areas that are difficult to access, waterlogged, largely radionuclide contaminated. The example of the Ukrainian part of the left-bank Pripyat drainage system within the Chornobyl Exclusion Zone shows that remotely obtained data together with the materials integrated into the geographic information systems of the terrestrial measurements provide the adequate monitoring information on the spatio-temporal changes in the hydrological and radioecological situation in general. Among the research methods, the simulation, the methods of hydrometric, balancing, remote sensing studies of water bodies were most used. The main purpose of the research is to perform the retrospective and current analyses of the hydrological situation based on archival and recent satellite images, assess the effectiveness of the water protection complex on the left bank of the Pripyat River, especially after the introduction of hydrotechnical measures to improve its radioecological status. In the research process the LANDSAT, SPOT, IRS, WorldView images were used. In particular, a significant sensitivity of the "surface water – dry land" system to the changes in the environment of this area was established and the mapping of objects of open water surface was performed as well as its spatial and temporal variability was followed. When comparing the results of calculations of the radionuclides carry-over by water (in particular, 90Sr) before and after the implementation of appropriate measures at the water protection complex the notable negative consequences of its implementation and operation during a period from 1986 to 2001 were revealed. It was found that the diverted one-time 90Sr carry-over due to the construction of a "new" left-bank dam (according to the 1999 flood scenario) is "compensated" by 40% through the increase of its carry-over prolonged in time as a result of operation of the polder pumping station (PPS) and the inundation of the contaminated areas, which is caused by the complicated conditions for the discharge of surface and underground runoff caused by the "new" and "old" dams. The ecological advisability and validity of hydraulic measures (clearing of canals, reconstruction of culverts) and the recommended form of the operational complex (without the use of PPS, with natural filtration discharge of the body of the "new" sand dam in the Pripyat River) are confirmed by the results of thematic interpretation of the multiband images. Thus, within the complex, minor flooding and waterlogging of the inter-dam section, as well as areas to the north-east from the "old" dam are established. Prospects for the further research of various hydrological processes and radioecological situation on the left bank of the Pripyat River are seen in the use of high resolution remote surveys, which would be performed over the short periods of time. The informative result in good quality can be obtained on the basis of the use of unmanned aerial vehicles technology.

PEMANFAATAN ABU ECENG GONDOK SEBAGAI BAHAN TAMBAH UNTUK MENINGKATKAN KUAT TEKAN BETON

Hyacinth plant in Latin terms called Eichhornia crassipes is an aquatic plant that until now is still considered a pest of the gadfly and is very difficult to destroy. This is because hyacinths have very fast growth properties and have good survival. Hyacinth is an aquatic plant that absorbs a lot of water, causing a lot of surface water to decrease a lot to reach four times when compared to an open water surface and this plant can also cause siltation in rivers or swamps, closures in river grooves or other swamp areas. But on the other hand, it shows that hyacinth plants can be used for home industry and also a very high fiber content. If hyacinth is burned, it will produce ash containing silica (SiO2) which can be used to add material to the concrete mixture. This study aims to find out the best variation in the addition of hyacinth ash so as to produce the most optimal compressive strength by adding hyacinth ash starting from 6%, 7.5%, 9%, 10.5%, 12%, 13.5% and 15% to the weight of cement in karaktristic concrete Fc'= 22 Mpa and the concrete compressive strength test is carried out at the age of 28 days. From the test results, it can be seen that the compressive strength of concrete at the age of 28 days obtained the most optimal conditions occurred in the addition of hyacinth ash of 10.5% in concrete mixtures with the resulting cartrictic compressive strength of 25.46 Mpa, this condition led to an increase in the compressive strength of concrete as large as 13.86% of normal concrete.