Water Content Of Rivers Research Articles

Nitrogen fate in riparian zones: Insights from experiments and analysis of sediment porosity and surface water-groundwater exchange

Riparian zones play a vital role in the river ecosystem. Solutes in vertical riparian zones are transported being by alternating hydraulic gradients between river water and groundwater, due to natural or human activities. This study investigates the impacts of porous sediments and alternating rate of surface water-groundwater on nitrogen removal in the riparian zone through experiments based on the field sampled. The experimental results, combined with dimensionless numbers (Péclet and Damköhler) and Partial Least Squares-Path Modeling, analyze the nitrogen fate responding to hydrodynamics changes. The results show that increased sediment porosity contributes to the ammonium removal, particularly when the oxygen content of river water is low, with the removal rate up to 72.57%. High ammonium content and dissolved organic carbon (DOC) in rural rivers lead to a constant low-oxygen condition (4 mg/L) during surface water-groundwater alternation, and promote denitrification. This threatens groundwater with ammonium pollution and causes accumulation at the top of vertical riparian zones during upwelling, potentially causing secondary river pollution. However, increasing the alternating rate hinders the nitrate denitrification and drastically changes in the redox environment of the riparian zone, despite contributing to ammonium removal. Rapid oxygen consumption during aerobic metabolism and nitrification in groundwater-surface water exchange created favorable conditions for denitrification. Floodplains sediment porosity is unfavorable for nitrification. This study improves understanding of coupled hydrologic and solute processes in vertical riparian zones, informing strategies for optimizing nitrogen attenuation and riparian zone construction.

Use of isotope techniques to evaluate the recharged ability of the upper Pleistocene aquifer in the Nambo Plain

In the Nambo Plain, the monitoring data on dynamics and quality of groundwater has shown declining signs in quantity and quality both in the existing groundwater aquifers, and the exploitation of groundwater in recent time is believed to be a cause of this decline. That shows the need for further research, especially on the modern recharge ability of the existing groundwater aquifers, to re-evaluate the groundwater potential of the region. For that purpose, isotope techniques are applied to evaluate the recharge ability of the upper Pleistocene aquifer, an important source of water supply in rural areas in the Nambo Plain.
 In this study, groundwater, river water and rainwater samples were collected and analyzed for stable isotope composition, tritium, radiocarbon and major hydro-chemical parameters. Data on stable isotope composition in groundwater are used to define the origin of groundwater while tritium and 14C content are used to determine groundwater age and to predict the aquifer’s recharge zone; and in combining with the stable isotope composition and tritium content of river water to evaluate the dynamic relationship between river water and groundwater.
 The obtained results show that: i) Groundwater in the study aquifer is originated from meteorological water and formed at different stages. ii) The high 3H and 14C content in some groundwater samples indicate that the aquifer has modern rainwater infiltrated as a recharge source. iii) The similarity of stable isotope composition in the Vam Co river water and groundwater adjacent to the river shows that there is a hydraulic relationship between them. This is an important basis for assessing the recharge ability to the qp3 aquifer of the Vam Co river water.

Оценка состава водных масс восточной части Баренцева моря с использованием современных данных о параметрах δ18O и δ2Н

This paper presents the results of measurements of δ18O and δ2H stable isotope values in the waters of the Barents Sea, which were carried out in March–April 2021. Based on the data presented, the ratio of base water content – atlantic (fa), river (fr) and melt water (fi), as well as the volume of water withdrawn for ice formation in the studied water area was assessed. The comparative estimation of base water content, calculated on values “δ18O–salinity” and “δ2H–salinity” is presented and obtained values do not exceed limits of mean value ±sd. However, average values of Atlantic and ice water content calculated using δ2H parameter are higher than those using δ18O, and river water content is lower. The use of δ18O and δ2H parameters in oceanographic studies in the calculation of balance characteristics is preferable to temperature and salinity because of their greater conservativity.

Hydrochemical characteristics of the Upper reaches of the Tisza River


 
 
 The purpose of this study is to analyse the hydrochemical regime and surface water quality of the upper reaches of the Tisza River from its source to Tiachiv, which also includes the transboundary section of the river. The data of the Borys Sreznevskyi Central Geophysical Observatory of the State Emergency Service of Ukraine for the period 1984-2018, as well as the results of route surveys during 2015-2018 served as materials for the study. The hydrological parameters of the river, in particular the level and flow of water, the distribution of the flow and the change of power sources throughout the year were analysed. Based on of the collected materials, a detailed analysis of the hydrochemical indicators of the water quality of the Tisza, Black Tisza, and White Tisza rivers was carried out. During the research, the natural conditions of the territory and economic activity were studied and their influence on the values of physic-chemical indicators, main ions and mineralization of water, biogenic substances, heavy metals and specific pollutants was analysed. The ratio of seasonal, average annual, average multi-year and maximum permissible concentra-tions (MPC) of hydro-chemical indicators was considered to determine their seasonal variability and multi-year dynamics. The role of natural factors in the formation of the chemical composition of river waters is determined, and the main sources of anthropogenic influence are also indicated. Seasonal variability of the indicated groups of indicators was also analysed considering different phases of river water content. It was determined that the waters of the headwaters of the Tisza River are calcium carbonate, moderately fresh with average mineralization (192-245 mg∙dm-3) and clear seasonal variability. Cases of increased concentrations of nitrogen-containing compounds in the waters of the upper reaches of the Tisza River due to the intensive decomposition of organic substances from house- hold wastewater were revealed. High concentrations of iron in river waters were recorded, which is related to the peculiarities of the geological structure of the territory. The seasonal variability of the content of synthetic surfactants was established. A decrease in the content of specific pollutants during the study period was observed.
 
 

CHANGE WATER CONTENT OF THE VORSKLA RIVER ACCORDING TO THE DATA OF THE HYDROLOGICAL POST OF THE VILLAGE OF CHERNECHCHYNA IN THE PERIOD FROM 1979 TO 2019

The article is devoted to an important problem of today – the analysis of water content of rivers using the example of the Vorskla River, a left-bank tributary of the Dnieper, which originates outside the Sumy region and flows through the territory of the region for about 122 km (26.3% of the river's length). The Vorskla River is characterized by the processes of overgrowth and silting, the river loses its water content and turns into a low-flow reservoir in places, therefore the outlined problem is extremely important. The purpose of the study: to analyze the water content of the Vorskla River using the important quantitative characteristics of the flow of expenses of water to the data of the hydrological post of the village of Chernechchyna in the period from 1979 to 2019. The article considers the concept of water content and describes the research methodology, analyzes the main quantitative characteristics of river flow: expenses of water (average, maximum and minimum). It was established that the average annual expenses of water of the Vorsklа River is characterized by a steady downward trend, low-water years prevail over high-water ones, and the low-water phase has been ongoing since 1989; the value of the indicator of maximum expenses of water decreases sharply, 73.2% of the data of the sample has a value less than 161,3 m3/s, only in 1980 the highest indicator of 585 m3/s was recorded, which is 1,3 times lower than the maximum multi-year expenses of water; the dynamics of the minimum expenses of water of the Vorskla River shows a wave-like downward dynamics, over the past 10 years, the indicator of the minimum expenses of water has decreased and its average value for the period 2010-2019 is 2,23 m3/s, the lowest minimum expenses of water was recorded for the period 1979-2019 (1,52 m3/s) are 6,4 times higher than the minimum multi-year indicator; the trend that scientists state about the intra-annual redistribution of flow is clearly followed (the hydrological indicators of high water are decreasing, and low water, on the contrary, are increasing); all signs of low water are present: all investigated quantitative indicators of flow are decreasing.

Probabilistic-forecasting method for determination of low flow discharge of Pivdennyi Buh, Black Sea area, and Lower Dnieper rivers

The aim of the study is to substantiate the probabilistic-forecasting method for forecasting the low flow discharge and its implementation for the Pivdennyi Buh, Black Sea area and Lower Dnieper rivers, taking into account climatic patterns of precipitation distribution and establishing probabilistic characteristics of low flow discharge in multi-year period. The study area is in a zone of significant risk due to the shortage of water resources, the formation of extremely low runoff in the dry flow period, which requires its definition and forecasting. The methodological basis of forecasts is to solve the equation in determining the components of the low flow of rivers by constructing regional dependences for forecasting the average decade summer-autumn low flow from previous water discharge (in runoff modules), establishing their probabilities water discharge for a number of intakes. Results. The paper substantiates the probabilistic-forecasting method for forecasting low flow discharge (in summer, autumn and winter periods) based on the construction of regional dependences of average decadal runoff modules on previous water discharge for groups of basins of studied rivers taking into account climatic dependences of precipitation distribution in the territory and the establishment of probabilistic characteristics of the low flow water discharge in a multi-year period. The methodology of territorial short-term forecasts of average decade water discharge of low flow of summer, autumn and winter river runoff is assessed as satisfactory with a margin of error of 70 % to 97 %, with a number of members of more than 500 points. To determine the cumulative probability of the forecast values of the average decade water discharge of the summer, autumn and winter dry weather flow, the empirical distribution of the average monthly water discharge in the limited seasons, which are generalized in the basins of the studied rivers of Ukraine, is established. Scientific novelty. For the first time for the zone of insufficient natural water content of rivers the method of territorial forecasts of low flow discharge, determination of their probability of occurrence in a multi-year period and cartographic representation of prognostic values have been developed and practically implemented. The practical importance is the use of forecast modules maps of low flow for spatial monitoring and assessment of low water levels on rivers in the whole region, including ungauged rivers, and their probabilistic characteristics – to assess the possible occurrence of low runoff, even when it reaches values close to the environmental runoff, which are critical for the functioning of the river ecosystem.

Знахідки та особливості екології видри річкової (Lutra lutra) на території Національного природного парку «Бузький Гард»

Information on new finds of the Eurasian otter (Lutra lutra) in the territory of Buzkyi Gard National Park is given. Some data are also given on the specifics of the otter’s diet, including its preying on animal species that are included into protection lists. The case of late (autumn) reproduction of otters is noted and described. The state of the otter population within the national park and the probable threats for this species related to the decrease of the river water content were assessed. The high level of rarity in the national park’s fauna and its concentration in small areas have been confirmed.

Analisis Tingkat Pencemaran Air Sungai Berdasarkan Kadar Fluorida Di Kota Mataram Menggunakan Metode Spektrofotometri UV-Vis

River water pollution levels can be analysed based on fluoride levels. Excessive fluoride levels will cause fluorosis of the bones. While fluoride deficiency will cause brittleness of teeth and thinning of bones. The purpose of this study was to determine the level of river water pollution based on fluoride levels in Mataram City. Fluoride levels were tested by adding a solution of zirconyl alizarin as a reagent and a solution of Na arsenite, which was then analysed by UV-Vis spectrophotometry with a wavelength of 535 nm. The results showed that the fluoride levels in the 7 tested samples met the fluoride quality standards. The highest fluoride content of river water in Mataram city is 1.046 mg/L, while the lowest is 0.213 mg/L. From this study it can be concluded that based from 7 points location water river sample in Mataram City are not polluted by fluoride.

COMPARATIVE ANALYSIS OF THE CHEMICAL COMPOSITION OF WATERWATER IN THE SLAVSKY DISTRICT OF THE KALININGRAD REGION BY HYDROLOGICAL SEASONS

The aim of the work is to research the chemical composition of surface watercourses in the Slavsky district of the Kaliningrad region in the winter hydrological season, and to compare the results with the data previously obtained by the authors for the autumn hydrological season and partly for the summer hydrological season. Watercourses and monitoring points for research have been identified: r. Zlaya, r. Shluzovaya, r. Nemoninka and r. Osa. In the winter season, water samples were taken, hydrometric characteristics were measured, and primary hydrochemical indicators were determined. On the basis of the obtained hydrochemical data, integral indicators were calculated to assess the quality of water, using combined lists of maximum permissible concentrations of pollutants. When monitoring hydrochemical indicators, it was revealed that the studied watercourses are, to one degree or another, subject to pollution. The water quality class in them varies from "moderately polluted" to "extremely dirty". When comparing the seasons, a tendency was revealed to improve the quality of water, which is associated with the water content of rivers, as well as with the cycles of natural and anthropogenic activity. The work has theoretical and practical significance. The data can participate in the planning of rational use of natural resources and the selection of measures to improve the geoecological state of the river network of the Slavsky region. The research can serve as a supplement to the formation of the general geoecological picture of the Kaliningrad region.

Assessment of the Seasonal Water Quality Changes in Semi-Urban Surface Tanks of Noyyal River Basin

Aims: The history of Noyyal river in Coimbatore is known for water quality and taste since the colonial period. The river water is used mainly for drinking, irrigation and industrial purposes to districts of Coimbatore, Tiruppur and Karur with many anaicuts and tanks. In the recent past due to urbanization and industrialization the river water has been polluted in the greater extend.
 Place and Duration of Study: The study was conducted to investigate the water quality status of five important upper reach semi-urban tanks of Noyyal river basin in the year 2020 -2021.
 Methodology: We have collected the sample season wise in the five tanks and analyzed for pH, EC, TDS, TSS, total hardness, alkalinity, chlorides and sulphates as well as heavy metals such as zinc, copper, cadmium and lead.
 Results: The results of our water quality analysis showed that most of the parameters are above the maximum permissible limits of CPCB standards for drinking water in India. The heavy metals concentrations were many folds higher than the CPCB permissible limits. The correlation analysis, Anova and PCA showed that the EC and TDS, alkalinity and sulphates, chlorides and sulphates and alkalinity and chlorides had higher correlation in the water quality analysis and they are interrelated to one another. In the monsoon season the pollution status is less and during summer season the pollution load is higher in the all tanks. During the monsoon season because of intensive water flow dilute the pollution load as well high rate of degradation due to high dissolved oxygen content of river water. Since, he Noyyal river is seasonal river, during summer, there would be very less or no flow of water into the tank increase the pollution load. The Narasampathy tank had comparatively less pollution than other tanks, since, it is the first tank in the upper reach of the Noyyal basin and has less inhabitants and industry.
 Conclusion: We concluded that the tanks are polluted due to urbanization and industrialization in and around the Noyyal basin and there is an urgent need to tackle this problem by making eco-friendly and economically viable treatment system to sustain the water quality.

Environmental impact assessment of tofu production process: case study in SME Sugihmanik, Grobogan

Tofu contains various substances that are very good when consumed to improve people’s nutrition. In addition, tofu also has good taste. The problem is that the tofu production process produces products and non-product outputs in the form of waste that is very dangerous if directly disposed of in the environment. The BOD5 content of tofu small and medium-sized enterprises (SMEs) in Sugihmanik Village ranged from 3,667-4,933 mg/L and COD 7,668-9,736 mg/L. At the same time, the TSS values ranged from 701-1,189 mg/L. The BOD5 value in the river water content is 367 mg/L. It greatly exceeds the set Threshold Value. This study aims to measure the environmental impact using Life Cycle Assessment (LCA). LCA can identify the impact of each activity based on the impact category to identify the processes that contribute significantly to damaging the environment. This study found that the cooking and frying process had the highest impact, where the climate change category was the largest. Wastewater treatment plants, biogas from the biodigester as a substitute for electricity for water pumps, rice husks, and corn cobs are expected to reduce environmental impacts. The first section in your paper

О ТЕРМИЧЕСКОМ РЕЖИМЕ ПРИЗЕМНОГО СЛОЯ ВОЗДУХА В БАССЕЙНЕ РЕКИ ДЕБЕД (АРМЕНИЯ)

The features of the thermal regime of the surface air layer in the Debed river basin are considered. A statistical analysis of the average annual and average seasonal values of air temperature from 1964 to 2018 was carried out, two periods were identified, their time course was shown. The analysis was carried out using data from six meteorological stations representing the lowland, mountain and high-mountain climatic zones of the Debed river basin. A correlation was obtained between the absolute altitude and the monthly average values of air temperature for January and July, which can be used to assess the thermal conditions of unexplored or poorly studied territories and for cartography. The time course of average values of air temperatures for the seasonal period has been studied. Analysis of trend lines of temporal changes in air temperatures shows that in all situations on the territory of the basin as a whole, there is a tendency of temperature growth. Moreover, with a range of interannual fluctuations, a break in the course of temperatures in the early to mid 1990 is clearly visible, after which their significant increase began. It turned out that a significant increase in seasonal temperatures is observed especially over the period 1993-2018, which means that the annual warming after the mid 1990 occurred primarily due to summer and spring seasons. The regular dynamics indicates that in the studied area in terms of temperatures, a tendency of softening winters, a decrease in the water content of rivers, aridization of the climate. The results obtained can be used to assess the regularities of the spatial-temporal distribution of the temperature of the study area, to clarify the thermal balance, for the rational use of heat resources, as well as in the development of strategic programs for longterm analysis.

МЕТОДИКА ОЦЕНКИ И АНАЛИЗА АНТРОПОГЕННОЙ НАГРУЗКИ НА РЕКИ ОТ ТОЧЕЧНЫХ ИСТОЧНИКОВ ЗАГРЯЗНЕНИЯ

Wastewater discharge into rivers has a negative impact on the quality of water resources. The existing methods for assessing the anthropogenic load from the discharge of wastewater into rivers do not allow one to compare and rank according to the degree of load rivers that differ in the size of the catchment area and are located in different natural zones. The author has developed a method for assessing and analyzing the anthropogenic load on rivers from the discharge of pollutants, which takes into account the water content of rivers and basin features of the formation of the quality of water resources. The proposed method makes it possible to determine the integral and differentiated loads for priority pollutants. It allows you to decompose the load into separate components (nitrogen, phosphoric, sulfate, chloride, etc.), to standardize the load taking into account the quality of river waters and to assess the priority of specific pollutants. This method has been tested on 12 rivers in Russia located in different natural and climatic conditions and having a wide range of water runoff values from 10 to 600 km3 / year. The calculation results showed that p. The Volga is experiencing the greatest anthropogenic load from the discharge of pollutants in wastewater. Therefore, first of all for the river. On the Volga, it is necessary to develop a basin program for the gradual reduction of anthropogenic load and mechanisms for its implementation

Organic matter reduction using four densities of seaweed (Gracilaria verucosa) and green mussel (Perna viridis) to improve water quality for aquaculture in Java, Indonesia

The high organic waste content of river water in Demak, north coast of Java, has caused traditional small-scale pond farmers to stop stocking shrimp. This paper examines whether seaweed and mussel will improve the quality of water these farmers use. The effect of Gracilaria verucosa and Perna viridis on the water quality was assessed by measuring the removal rates (RRs) of total organic material (TOM), total ammonia nitrogen (TAN), nitrite, and nitrate. The specific growth rates (SGRs) of seaweed and mussel were also measured. Thirty-six semi-outdoor tanks containing 800 L of brackish water and 7 cm substrate were randomly assigned to four replications of four densities of G. verucosa: 50 (S50), 100 (S100), 150 (S150), and 200 (S200) g m−2, and of P. viridis: 60 (M60), 90 (M90), 120 (M120), and 150 (M150) g m−2. Weekly, the TOM, TAN, nitrite, and nitrate contents were measured, seaweed and mussel weighted; RRs and SGRs were calculated at the end of the study. The effect of densities on the RRs was significant for both seaweed and mussel. P. viridis was more effective in reducing TOM (by 38%) than G. verucosa (7%); G. verucosa achieved higher RRs for TAN, nitrite, and nitrate. At S200, TOM and TAN decreased by 7.4% and 67%, respectively. At M90, TOM and TAN, decreased by 38% and 49%, respectively. However, nitrite increased significantly at S200 and M150. The SGR of seaweed was significantly lower at S200 than that at S150, S100, and S50. The best performing densities were S100 and M90.

Оперативный учет речного стока в условиях неустановившегося движения потока (на примере реки Яна в гидростворе города Верхоянска)

The real-time water discharge computation involves practical real-time computation of water discharge values to ensure forecasting and preventing dangerous hydrological phenomena, as well as daily monitoring of river water content and information support for the functioning of water management facilities in river basins. Nowadays the task of the real-time discharge accounting is very relevant. The article presents the outcomes of the study of two methods of computation of the real-time water discharges in the conditions of the unsteady flow that enable to pass to automatic operative accounting of the river flow. The first method is based on using of optimal extrapolation of the relative deviations of the measured water discharges from the reference rating curve obtained from the data of water discharge measurements for previous years. The second method is a new approach based on the Jones formula. The parameters of the Jones formula were obtained from measurements of water discharge over the past years using an optimization tool based on the generalized reduced gradient method. The daily real-time water discharges calculated in two ways were compared with the daily water discharges published in the reference books of the water cadaster «Daily data on the regime and resources of land surface waters». As a result, it was found that both methods can be used for automated real-time water discharge computation in conditions of unsteady flow.

Методика прогноза водности высокогорных рек Центральной Азии на основе снимков MODIS

The article investigates the possibility of using snow cover satellite data for short-term hydrological forecasting for Central Asian rivers with high-altitude catchments. The research aimed to elaborate a methodology for forecasting mean 10-day (decadal) river discharge (MDD) of the Varzob and Tar Rivers based on MODSNOW-processed MODIS satellite imagery. The objectives of the study were to calculate the snow cover index (SCI) for high-altitude zones in 200 m increments for selected river basins, and to analyze the closeness of dependency between the corresponding SCIs and MDDs. The research resulted in equations applicable for producing operational river water content forecasts. Timely and reliable information on expected river water content during the forthcoming 10-day period allows decision makers (water management and hydropower agencies, emergency authorities) plan water supply for various economic sectors, as well as take measures to prevent hazardous hydrological phenomena on the rivers of Tajikistan and Kyrgyzstan.

ВЗАИМОСВЯЗЬ КЛИМАТА И РЕЧНОГО СТОКА (НА ПРИМЕРЕ БОЛЬШОГО КАВКАЗА В ПРЕДЕЛАХ АЗЕРБАЙДЖАНА)

Problems of climate change impact on the water regime of the Azerbaijan rivers were considered. Precipitation (X), temperature (T) were analyzed and changes in river runoff were evaluated under different temperature scenarios of individual height limits. Paired correlations between air temperature and precipitation were built, taking into account the distribution of these dependencies in the region in three study areas. For each district, the constraints of the waste model were built and their analytical definition was provided. The effect of climatic changes on the water content of rivers is determined by a decrease in atmospheric precipitation, which is the main balance component of river runoff, and an increase in evaporation from the surface of their basins. However, due to the lack of information on evaporation, the impact of climate on river flow was calculated from atmospheric precipitation and temperature. An analysis of their trends showed that throughout the republic (under various physical and geographical conditions and at various altitudes) has been an increase in annual temperatures from +0.3°C to + 1.7°C in Ganja in recent years. The temperature increase gradient in the highlands is greater. The increase in the average long-term temperature in the republic is + 0.9°C since 1991.

RELATION OF EXTREMES OF MINIMUM WINTER RIVER FLOW WITH TEMPERATURE AND ICE FACTORS

Studies performed in different river basins in the North-West of Russia have shown that a combination of temperature and ice conditions plays a significant role in changing the winter water content of rivers. Air temperature and ice thickness are integral indicators of changes in thermal conditions in the river basin and in the river, regulating through cryogenic processes the supply of groundwater and its discharge into rivers in winter. Therefore, the main predictors used in the work are air temperature, ice thickness, and winter river flow. To obtain quantitative estimates, a comparative analysis of changes in river flow by the end of winter under different temperature and ice conditions was performed. The series of winter runoff of rivers in the basins of the Lovat, Syas, Northern Dvina and Onega rivers with the total period of observations of the runoff and the thickness of the river ice are analyzed –1955-2016 years, temperature – 1936-2016 years. Based on the analysis of a series of observations of river flow, ice thickness, and air temperature lasting more than 50 years, it is concluded that the lowest values of the minimum winter flow of rivers were observed in cold winters, and the highest values were observed in milder winter seasons. With comparable pre-winter water content of rivers in a series of mild non-thawing winters, river flow in the studied basins decreased less intensively and the minimum winter flow was higher on average by 10-20%, and in some cases more.

РОЗРАХУНКОВІ ХАРАКТЕРИСТИКИ СЕРЕДНЬОГО РІЧНОГО СТОКУ ВОДИ ПРАВОБЕРЕЖНОЇ ТА ЛІВОБЕРЕЖНОЇ ЧАСТИН БАСЕЙНУ Р. ДНІСТЕР ДО М. ЗАЛІЩИКИ

The Dniester River is the second longest and most watery river in Ukraine, which is characterized by heterogeneity and diversity of conditions for the formation of water flow, both in terms of its length and numerous tributaries. The right-bank and left-bank parts of the Dniester River basin are quite different in terms of physical and geographical conditions, drainage network density, water regime and river water content. The object of the study is the average annual water flow of the rivers of the Dniester River basin, the subject is its calculated characteristics of different probabilities of exceeding. The purpose of the study is to analyze, systematize, generalize and compare the calculated characteristics of the average annual water flow of rivers of the right-bank and left-bank parts of the Dniester basin. Input data is based on the average annual river water discharge from 50 stream flow measuring stations in the Dniester River basin (to Zalishchyky). The data bank was formed from the beginning of observations until 2016. 89% of 28 right-bank stream flow measuring stations have a continuous series of more than 50 years, and 86% of 22 left-bank stream flow measuring stations have a continuous series of observations of more than 50 years. As for the catchment areas of rivers in the closing areas, the right bank is dominated by small ones – 64% of 28 stations have an area of less than 500 km2 and 25% – from 500 to 1,000 km2. 37% of 22 stations on the left bank have a catchment area of less than 500 km2 and 41% – from 500 to 1,000 km2. According to statistical criteria, the series of observations of the average annual river water discharge in both parts were mainly homogeneous and representative. Analytical distribution curves were calculated by the method of moments, as the coefficients of variation do not exceed 0.50. Generalization and comparison of the calculated characteristics of the average annual water flow of different probabilities of exceeding the rivers of the right-bank and left-bank parts of the Dniester basin have shown that the smallest scatter of certain analytical ordinates is observed for the probability of exceeding 50%, the transition coefficients from the norm are close to 1. The greatest spread of variation of ordinates is observed at extreme probabilities of excess of distributions, that is 0,01 % and 99 %. Analysis of the ranges of variability of transition coefficients from the norm of average annual water consumption has shown that the intensity of their change in the region of rare probabilities (0.01, 0.1, 1 %%) on the left bank is more significant than on the right bank of the Dniester basin. As for low-water supplies (95, 97, 99 %%), their ranges of variability coincide in both studied parts.

ANALISIS PERANCANGAN STRUKTUR BANGUNAN ATAS JEMBATAN AMPERA DI SUNGAI DIGOEL PAPUA

Digoel river which separates between the western and eastern parts of Boven Digoel is a type of meander river (winding).Digoel river flow always changes in each period, so that the type of river Digoel influenced the method of designing and implementing the construction of a bridge that connecting Tanah Merah with Kampung Ampera significantly. The aim of this study wasto analyze the results of the feasibility study relating to the design of upper structures of Ampera bridge in Boven Digoel, Papua. The research method was carried out by conducting the laboratory and field experiments to obtain parameters in designing a bridge. The laboratory experiments which had beenconductedwereaggregate materials (sand and gravels) and river water content tests. The fieldexperiments were topography, bathymetry, geoelectric, and soil tests. The structural analysis were conducted using a computer program (MIDAS), then based on the obtained data from the analysis results and evaluation, the type of bridge and planningcould be determined. The Ampera Bridge that connects Tanah Merah with the village of Ampera was designed using a type of curved bridge ona main span of 200 meters. The approach bridge was built by a span of 40 meters and 60 meters of steel frames. The total length of the planned bridge is 600 meters.