scholarly journals SCALE AND LONG-TERM DYNAMICS OF OKA RIVER BASIN POLLUTION

2021 ◽  
Vol 26 (2) ◽  
pp. 40-53
Author(s):  
R. G. Dzhamalov ◽  
◽  
K. G. Vlasov ◽  
V. Y. Grigorev ◽  
K. G. Galagur ◽  
...  
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Linear Trend ◽  
Statistical Significance ◽  
Rank Correlation ◽  
Correlation Coefficients ◽  
Kendall Test ◽  
Anthropogenic Load ◽  
Treated Wastewater

Introduction. This article addresses the long-term dynamics of Oka River basin pollution. The basin serves as the main source of drinking water and a receiver of wastewater from a number of regions in European Russia. Methods. We assessed the water quality by 12 main hydrochemical indicators and constructed maps of their distribution with a breakdown into two periods (1990–1999 and 2000–2017). The anthropogenic load along the section in the city of Gorbatov was determined. Spearman’s rank correlation coefficients and their statistical significance were calculated. Results. For 18 gauging stations with 25 and more years of observations, the magnitude of the linear trend (%/year) was estimated using the Theil–Sen estimator, and the statistical significance of the linear trend (Mann–Kendall test) was assessed for individual stations and the entire basin, using a modified Walker test. The runoff of pollutants from the urban territory was estimated between the sections upstream and downstream the cities in the upper reaches of the Oka River basin. The volumes of pollutants in the Oka River from the cities of Orel, Belev and Kaluga were determined for the period of 1990–2017. The calculations of the pollutant runoff, performed between the sections upstream and downstream the cities, made it possible to determine the role of the cities in the formation of point pollution in the upper reaches of the Oka River. The anthropogenic load along the length of the river in terms of the influx of chemicals varies from “low” to “high”. The load is largely due to the intake of pollutants since water bodies and watercourses serve as receivers of both treated and insufficiently treated wastewater from various enterprises. Conclusion. Almost throughout the basin, the water quality is under stress. The statistical analysis showed the existing relationship between a certain type of land use and the concentration of substances in surface waters. It was revealed that the self-cleaning capacity of the river is sufficient to prevent pollutants from accumulating along it.

scholarly journals Integrated Assessment of the Southern Bug River Basin Water Quality and Calculation of their Self-Cleaning Capacity

2021 ◽  
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
River Basin ◽  
System Analysis ◽  
Statistical Parameter ◽  
Kendall Test ◽  
The Self ◽  
Ecological Index ◽  
Mann Kendall Test

Purpose. To carry out the surface water quality assessment of the Southern Bug river basin and to investigate the ability of surface water to self-purify. Methods. Statistical calculations, system analysis. Results. The long-term dynamic of the integrated quality index values of the Southern Bug during 2000-2016 was heterogeneous, but the general trend indicated a slight increase due to the sanitary-ecological index and pollution index. The highest level of water pollution was observed in Khmelnytsky city and Alexandrovka settlement. To assess the self-purification capacity of surface waters, the hydrological zoning of the basin was taken. According to it three regions were identified by the types of intra-annual runoff distribution: Verkhnyobuzky, Serednyobuzky and Nizhnobuzsky. The obtained results of EC coefficient calculations for mineral nitrogen compounds show the inability of rivers to self-purify for Verkhnyobuzky and Serednyobuzky regions. Instead, the ability to self-purify is preserved for phosphorus compounds.Using the nonparametric Mann - Kendall test allowed to estimate the long - term trend of nutrients for the Nizhnobuzsky hydrological region. Trends N-NO3-, N NH4+and Р-РО43- are characterized by positive values of the statistical parameter, which means the increasing of these elements’ concentrations. Conclusions. Rivers of the Southern Bug basin are classified as "good, clean enough". The main ecological and hydrochemical problems of the river are pollution by nutrients and indicators of toxic action. The results of the self-purification criterion calculations indicate their inability (in the upper and middle parts of the basin) to self-purification. Using of the nonparametric Mann-Kendall test for determining changes in nutrient compounds shows an upward trend, that means increasing of their concentrations.

scholarly journals Rainfall trend and variability over Opak River basin, Yogyakarta, Indonesia

2020 ◽  
Vol 1000 (1000) ◽  
Author(s):  
Wakhidatik Nurfaida ◽  
Hendra Ramdhani ◽  
Takenori Shimozono ◽  
Indri Triawati ◽  
Muhammad Sulaiman
Keyword(s):  
River Basin ◽  
Water Resource ◽  
Rainfall Intensity ◽  
Kendall Test ◽  
Rainfall Data ◽  
Positive Trend ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Slope Estimator

Rainfall intensity seems to be increasing nowadays due to climate change as presented in many studies of both global and regional scale. Consequently, cities worldwide are now more vulnerable to flooding. In Indonesia, increasing frequency of floods was reported for the past decades by The National Agency for Disaster Countermeasure (BNPB). To understand the rainfall changes, long-term trend evaluation over a specific area is then crucial due to the large variability of spatial and temporal rainfall distribution. This study investigates the homogeneity and trend of rainfall data from 20 stations over the Opak River basin, Yogyakarta, Indonesia. A long-term ground observation rainfall data whose period varies from 1979 to 2019 were analyzed. Non-parametric Mann – Kendall test was applied to assess the trend, while the magnitude was calculated using the Sen’s slope estimator. An increasing annual maximum of daily rainfall intensity was observed at four stations on a 0.95 confidence level based on the Mann – Kendall test, while the Sen’s slope estimator shows a positive trend at almost all stations. The trend of heavy rainfall frequency was also found to be significantly increased, with only one station showed a decreasing trend. Furthermore, this paper also described the spatial and temporal rainfall variability. Positive trend was mostly found during the rainy season, while the negative trend occurred during the dry season. This could pose a challenge for water resource management engineering and design, such as water supply systems or reservoir management. Understanding this phenomena will benefit hydrologists in preparing future water resource engineering and management.

scholarly journals Index-based and compliance assessment of water quality for a Brazilian subtropical reservoir

2018 ◽  
Vol 23 (5) ◽  
pp. 841-848 ◽  
Author(s):  
William Bonino Rauen ◽  
Ana Camila Ferraresi ◽  
Leila Maranho ◽  
Edinalva Oliveira ◽  
Rudhy Costa ◽  
...  
Keyword(s):  
Water Quality ◽  
Temporal Trends ◽  
Rank Correlation ◽  
Metropolitan Region ◽  
Biological Assessment ◽  
Trophic State Index ◽  
Reservoir Water ◽  
Spearman’S Rank Correlation ◽  
Physical Chemical

ABSTRACT The Passaúna catchment is part of the Upper Iguaçu watershed and includes a water supply reservoir for over 500,000 inhabitants of Curitiba metropolitan region. The aim of this study was to establish the state of reservoir water quality, and whether it has undergone any recent medium- and long-term variations. A physical-chemical-biological assessment was undertaken using nine indicators and three indexes: Water Quality Index (WQI), Trophic State Index (TSI) and Shannon-Weaver Index (H’) for macroinvertebrate diversity. Compliance with the prescribed quality standards for the water body was verified using frequency curves. Two WQI calculation approaches were contrasted to test for conditions of partial data unavailability. Temporal trends in key parameters were assessed using Spearman’s rank correlation coefficient. WQI results from 1991-2014 indicated that the water quality may be classified as good and improved in the final decade of such period, while most TSI results were in the oligotrophic/mesotrophic range, but with no significant temporal trend. The biodiversity result of H’=1.6 obtained with data acquired in 2014 indicated a moderately degraded ecosystem that is typically associated with flow regulation and a degree of water quality impairment. Such a multi-indicator integrated physical-chemical-biological monitoring approach comprised a robust framework for assessments of medium-long term aquatic health.

scholarly journals Trends of mean annual river discharges in the Zapadna Morava river basin

2017 ◽  
Vol 97 (2) ◽  
pp. 19-45
Author(s):  
Marko Langovic ◽  
Sanja Manojlovic ◽  
Zoran Cvorovic
Keyword(s):  
River Basin ◽  
Linear Trend ◽  
Active Surface ◽  
Kendall Test ◽  
Past Century ◽  
The Republic ◽  
Morava River ◽  
In The Beginning ◽  
The Given ◽  
Morava River Basin

Zapadna Morava River basin covers a surface of 15850 km2, which is approximately 18% of the territory of the Republic of Serbia. In its basin, 38 active surface stations are registered. The goal of this paper is the trend analysis of the mean annual river discharges in the Zapadna Morava River basin and their noticing in a longer series of time, as well as determining their intensity. Fifty years period of time (1965 - 2014) is taken for a time series. Because there is no empirical data for mean annual discharge values for all stations for the given period, the number of the hydrological stations, which are processed in this paper, is reduced to 21. Mann-Kendall test has been used for noticing the trend, Sen test has been used for estimating the curves inclinations of the linear trend, while Pettitt?s test has been used for determining the turning point of change. Also, classification of the years by water richness has been performed in this paper in order to determine wet and dry periods. For the needs of identification of medium watery, wet and dry years, the combined method has been used on the data examples from representative stations in the basin. Based on the processed data and the obtained results, it has been established that the most rivers in the basin of the Zapadna Morava River have a slightly decreasing trend of the flow values, whereby the change of the trend is not significant. On the most rivers, the change period has begun in the early eighties of the past century. On a large number of profiles, the watery period was appearing in the beginning of eighties, while the dry season is characteristic for the period from 1990 to 1994.

scholarly journals Groundwater Quality Assessment for Irrigation: Case Study in the Blinaja River Basin, Kosovo

2021 ◽  
Vol 7 (9) ◽  
pp. 1515-1528
Author(s):  
Hazir S. Çadraku
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Irrigation Water ◽  
Water Samples ◽  
Agricultural Crops ◽  
Irrigation Water Quality ◽  
Quality Of Water ◽  
Kelly’S Ratio

Groundwater is an important source for a drink and irrigation in the Blinaja river basin. Understanding knowledge of irrigation water quality is critical to the management of water for long-term productivity. Historically for this study area there is no data and information regarding the quality and use of water for irrigation needs. Therefore, there was a need to assess water quality based on data analysed from eight sampling points. The purpose of this paper is to evaluate, relying on analytical results, the quality of groundwater in the Blinaja river basin for the purpose of its use for irrigation of agricultural crops. For this purpose, in the Blinaja River Basin in different months during 2015, 2016, 2018 and 2019, 28 water samples were taken to assess the quality of groundwater for irrigation. Water samples were analysed in a laboratory for some of the key quality indicators; pH, EC, hardness (TH), Ca, Mg, Na, K, HCO3, SO4, Cl, etc. and then irrigation water quality indices were calculated such as: percentage of Na (% Na), SAR (Sodium Adsorption Ratio), PI (Permeability index), KR (Kelly's ratio), etc. The overall objective of this study was to assess the quality of water to be used by the inhabitants of the area for irrigation of agricultural crops. Analytical procedures for the laboratory determinations of water quality have been given in several publications (USDA Handbook 60 by Richards, 1954; FAO Soils Bulletin 10 by Dewis and Freitas1970; APHA 2005). Doi: 10.28991/cej-2021-03091740 Full Text: PDF

Evaluation of changes in streamflow and the underlying causes: a perspective of an upstream catchment in Haihe River basin, China

2018 ◽  
Vol 11 (1) ◽  
pp. 241-257 ◽  
Author(s):  
Sicheng Wan ◽  
Jianyun Zhang ◽  
Guoqing Wang ◽  
Lu Zhang ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Hydrological Cycle ◽  
Kendall Test ◽  
Haihe River Basin ◽  
Changing Environment ◽  
Haihe River ◽  
Hydrological Simulation

Abstract Investigating long-term streamflow changes pattern and its response to climate and human factors is of crucial significance to understand the hydrological cycle under a changing environment. Caijiazhuang catchment located within Haihe River basin, north China was selected as the study area. To detect the trend and changes in streamflow, Mann–Kendall test was used. Elasticity and hydrological simulation methods were applied to assess the relative contribution of climate change and human activities on streamflow variability under three periods (baseline (1958–1977), impact I (1978–1997), and impact II (1998–2012)). The long-term hydro-climatic variables experienced substantial changes during the whole study period, and 1977 was the breaking year of streamflow change. Attribution analysis using the two methods showed consistent results: for impact I, climate change impacts explained 65% and 68% of streamflow reduction; however for impact II, it only represented 49% and 56% of streamflow reduction. This result indicated that human activities were intensifying over time. Various types of human activities presented significant effects on streamflow regimes including volumes and hydrographs. The findings of this paper could provide better insights of hydrological evolution and would thus assist water managers in sustainably managing and providing water use strategies under a changing environment.

scholarly journals Fast-Track in-Stream Action to Enhance the Oxidative Capacity within Watershed

2020 ◽  
Vol 9 (3) ◽  
pp. 1014-1026
Keyword(s):  
Water Quality ◽  
Flow Condition ◽  
Fast Track ◽  
Drainage Water ◽  
Low Flow ◽  
Treated Wastewater ◽  
Organic Load ◽  
Drainage Network ◽  
Intermediate Shock

This work presents a non-conventional alternative for cleaning polluted agriculture drainage network within a certain watershed. In Egypt, a need for using marginal quality water in agriculture applications is becoming a great necessity due to water shortage. One important strategy to increase available water resources is to reuse agriculture drainage water for irrigation application. The water system, especially drainage network receives a remarkable amount of pollution (raw and partially treated wastewater). That results to an increase in organic load to an unacceptable level, accordingly, the water quality of the drainage water has been negatively affected and the "reuse" plan has been threatened. Fast-Track In-stream Action (FTIA) is an ongoing fast action suggested to control the pollution of drainage water within a certain watershed to make it more suitable for reuse practice. FTIA as a quick interfere will skip long-term processes of conventional water treatment stages to get satisfactory results in proper time. It presents a practical immediate solution to achieve acceptable level of water quality rather than waiting for full improvement through long-term and expensive conventional programs. In this study a biological maintenance solution was applied and tested in both bench and field scales to assess its efficiency in improving the water quality within selected watershed. An evaluation of this fast-track process was done by measuring a significant key water quality parameters (WQPs) at designed locations of the study area before, during and after application of material. For better explanation of overall water quality and proper comparison, a weighted arithmetic water quality index (AWQI) has been discussed based on eight selected WQPs. In addition to a bench-scale test, two other field investigations were adopted: the first one investigates the effects of fast-track resources when applying the bio-based material under high flow condition with intermediate shock flow (study area "1"), while the other one examine the application of material under low flow condition with intermediate shock pollution load (study area "2"). All indicators, including aesthetics showed improvements in selected WQPs and AWQI during the investigation period

scholarly journals Repeatability and randomness in heterogeneous freezing nucleation

2008 ◽  
Vol 8 (1) ◽  
pp. 4059-4097 ◽  
Author(s):  
G. Vali
Keyword(s):  
Statistical Significance ◽  
Strong Support ◽  
Rank Correlation ◽  
Correlation Coefficients ◽  
Cloud Models ◽  
High Statistical Significance ◽  
Immersion Freezing ◽  
Water Drops ◽  
Multiple Cycles ◽  
Freezing Temperatures

Abstract. This study is aimed at clarifying the relative importance of the specific character of the nuclei and of the duration of supercooling in heterogeneous freezing nucleation by immersed impurities. Laboratory experiments were carried out in which sets of water drops underwent multiple cycles of freezing and melting. The drops contained suspended particles of mixtures of materials; the resulting freezing temperatures ranged from −6°C to −24°C. Rank correlation coefficients between observed freezing temperatures of the drops in successive runs were >0.9 with very high statistical significance, and thus provide strong support for the modified singular model of heterogeneous immersion freezing nucleation. For given drops, changes in freezing temperatures between cycles were relatively small (<1°C) for the majority of the events. These frequent small fluctuations in freezing temperatures are interpreted as reflections of the random nature of embryo growth and are associated with a nucleation rate that is a function of a temperature difference from the characteristic temperatures of nuclei. About a sixth of the changes were larger, up to ±5°C, and exhibited some systematic patterns. These are thought to arise from alterations of the nuclei, some being permanent and some transitory. The results are used to suggest ways of describing ice initiation in cloud models that account for both the temperature and the time dependence of freezing nucleation.

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