scholarly journals Spatial/temporal Transformation of the Volga Reservoirs’ Ground Complex. Communication 5. The Ivankovo Reservoir Bottom Sediments and Water Quality

2018 ◽  
Author(s):  
Keyword(s):  
Water Quality ◽  
Bottom Sediments ◽  
Sediment Accumulation ◽  
Atmospheric Precipitation ◽  
Hydrodynamic Pressure ◽  
Temporal Variations ◽  
Coarse Grained ◽  
Observation Data ◽  
Ivankovo Reservoir ◽  
Long Term Observation

Conditions of formation, distribution, and accumulation of bottom sediments and chemical pollutants in the Ivankovo Reservoir and their impact on water quality have been considered on the basis of the long-term observation data. According to the monitoring results, it has been stated that current bottom sediments are composed of coarse-grained alluvium (38%), fine-dispersed sediments (38%), and soil (15%). Sediment accumulation decreased two folds under Transformation of the suspended matter balances caused two times decrease of sediment accumulation resulted in the increase of the amount of suspended solids saturated with pollutants. Considerable changes occurred in deposited macrophytes; their proportion increased from 16.7 to 26 – 28%, swamped soils constituted 14% of the reservoir area. The decrease in the rate of sedimentation and changes in the area of the reservoir caused a two-fold decrease in the rate of nutrient accumulation. Re-suspension of sediments and trans-sedimentation causing a secondary pollution of water with nutrients and toxic elements occur in the presence of vast shallow zones up to 3 m depth constituting about 53% of all area of the reservoir. As a result, the water quality is of a fluctuating character. This is especially distinctly manifested during the flood period when the maximum input of pollutants of natural and anthropogenic origin from residential territories, with atmospheric precipitation, ground and river runoff is observed upon filling the reservoir to the designed level and intensive hydrodynamic pressure. The results of hydrochemical surveys performed in 2012 and in the following years confirmed insignificant changes in physical and chemical parameters of elements of the ecosystem in the Ivankovo Reservoir. Since the construction of the reservoir permanganate oxidation, total iron, manganese, water mineralization and the content of the main ions are stable and depend on hydrometeorological conditions of the year. Interannual and seasonal dynamics of these parameters is observed. Despite the spatial and temporal variations, bottom sediments are the most conservative components in the environment.

scholarly journals Spatial-temporal Transformation of the Volga Reservoirs’ Soil Complex. Communication 7. Sediment Formation in the Highly Running Reservoirs of the Volga Cascade

2021 ◽  
pp. 29-46
Author(s):  
Keyword(s):  
Water Quality ◽  
Bottom Sediments ◽  
Flow Rate ◽  
Water Exchange ◽  
Operating Conditions ◽  
Coarse Grained ◽  
River Systems ◽  
Sediment Formation ◽  
Volga Reservoirs ◽  
Temporal Transformation

Large plain reservoirs are water bodies of a slow water exchange with Кw less than 10 year-1 contributing to multi-year (annual) flow regulation. All reservoirs of the Volga-Kama cascade belong to this type of reservoirs, except the Cheboksary and Saratov reservoirs with Кw about 20 year-1. Weekly and daily fluctuations of the runoff are observed in these reservoirs. This mode of operation of hydraulic constructions leads to an increase in the flow rate and fluctuations of the level, which determines the specific conditions for the formation and accumulation of bottom sediments characteristic of river systems. It is shown that the areas of coarse-grained sediments are 55 and 70%, respectively. The reservoirs under consideration are transit reservoirs for suspended substances and aerators for the oxidation of chemical pollutants and their neutralization, so they play a crucial role in the natural self-purification and management of natural water quality. Methods. The aim of the study is to characterize the spatial and temporal transformation of the lower layer of the ecosystem in reservoirs with high water exchange (by the example of the Cheboksary and Saratov reservoirs) and to identify its role in water self-purification taking into account biomarkers. It is known that river systems or systems similar to them are more efficient and are characterized as potentially saturated with food organic/mineral resources for hydrobionts. The assessment of water quality and bottom sediments of different hydro-morphometric characteristics, dynamics of water masses and operating conditions is presented using methods of bioassay and toxicology by the example of chironomid larvae and antioxidant defense system of benthic fish. Results. Based on the data of the integrated hydrobiological cruises during the growing season 2014–2020, it is difficult to say that the quality of water and bottom sediments, biotic and toxicological parameters depend on the flow rate, so further studies are required. The work is original, because there are no analogues in the world for monitoring of bottom sediments in reservoirs and quantitative assessment of sedimentation processes in space and time. The results of the biogeochemical analysis indicate, that in terms of the degree of deterioration of the eco/toxicological state, the Volga reservoirs are in a series: Volgograd = Saratov > Kuibyshev > Cheboksary > Gorky.

Spatio-temporal Variations in Water Quality Parameter Trends in River Waters

2018 ◽  
Vol 69 (10) ◽  
pp. 2940-2952 ◽  
Author(s):  
Martina Zelenakova ◽  
Pavol Purcz ◽  
Radu Daniel Pintilii ◽  
Peter Blistan ◽  
Petr Hlustik ◽  
...  
Keyword(s):  
Water Quality ◽  
Chemical Oxygen Demand ◽  
Quality Indicators ◽  
Water Resource Management ◽  
Oxygen Demand ◽  
Temporal Variations ◽  
Water Quality Parameter ◽  
Agricultural Activity ◽  
Water Quality Indicators ◽  
Nitrite Nitrogen

Evaluating trends in water quality indicators is a crucial issue in integrated water resource management in any country. In this study eight chemical and physical water quality indicators were analysed in seven river profiles in the River Laborec in eastern Slovakia. The analysed water quality parameters were biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), pH, temperature (t), ammonium nitrogen (NH4+-N), nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N), and total phosphorus (TP). Data from the monitored indicators were provided by the Ko�ice branch of the Slovakian Water Management Company, over a period of 15 years from 1999 to 2013. Mann�Kendall non-parametric statistical test was used for the trend analysis. Biochemical and chemical oxygen demand, ammonium and nitrite nitrogen content exhibit decreasing trends in the River Laborec. Decreasing agricultural activity in the area has had a significant impact on the trends in these parameters. However, NO2--N was the significant parameter of water quality because it mostly exceeds the limit value set in Slovak legislation, Regulation No. 269/2010 Coll. In addition, water temperature revealed an increasing trend which could be caused by global increase in air temperature. These results indicate that human activity significantly impacts the water quality.

Features of designing underwater crossings of main pipelines under the conditions of riverbed and floodplain multi-branchness

2021 ◽  
pp. 378-387
Author(s):  
Виктор Михайлович Католиков ◽  
Дмитрий Борисович Казиакбаров ◽  
Андрей Андреевич Мальцев ◽  
Анна Олеговна Власова
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Sediment Accumulation ◽  
Pipeline System ◽  
Technical Solution ◽  
River Bed ◽  
Regulatory Standards ◽  
Main Pipelines ◽  
The Amur River ◽  
Design And Construction

Многолетняя практика применения регламентных норм учета русловых процессов и механизма транспорта донных руслоформирующих наносов подтверждает надежность принятых расчетов для проектирования и строительства подводных переходов магистральных трубопроводов (ППМТ) через большинство средних и крупных рек России. Но для рек, «перегруженных» донными наносами, традиционные расчетные методики параметров подводной траншеи трубопровода с учетом заносимости оказываются недостаточными и требуют дополнительных решений. Данная проблема была выявлена при строительстве основной и резервной ниток ППМТ ВСТО-2 через реку Амур и обусловлена гидроморфологическими особенностями, спецификой водного режима и значительным расходом донных наносов, характерными для этого водного объекта. В настоящей статье представлена усовершенствованная технология разработки траншеи ППМТ путем создания так называемых ложных траншей на участках с максимальными удельными расходами донных наносов. На примере строительства ППМТ ВСТО-2 (резервная нитка через реку Амур) рассмотрены сложности проектирования и строительства трубопровода при значительных объемах транспорта донных наносов, проанализированы риски строительства в данных условиях, описаны планирование и реализация технического решения по созданию ложных траншей для перехвата донных наносов. The long-term practice of regulatory standards for recoding of river bed evolutions and the transport mechanism of bottom riverbed-building sediments proves reliability of the adopted calculations for design and construction of underwater crossings of main pipelines through majority of medium and large rivers of Russia. However, in respect of the rivers which are «overloaded» with bottom sediments, the conventional calculation methods of parameters of the underwater pipeline trench, considering sediment accumulation, are insufficient and require additional solutions. This problem was identified during construction of the underwater crossing of the ESPO-II pipeline system across the Amur River and is associated with hydromorphological features, specifics of the water regime and significant flow rate of bottom sediments typical for this water body. This article presents an improved technology for developing an underwater trench by establishment of so-called false trenches in the areas with maximum specific flowrate of bottom sediment. Based on the example of construction of the underwater crossing of the reserve pipeline leg, the difficulties related to design and construction of a pipeline with significant amount of bottom sediment transport are considered, risks of construction under these conditions are analyzed, planning and implementation of a technical solution for establishment of false trenches for intercepting bottom sediment are described.

scholarly journals Temporal Variation of Chlorophyll-a Concentrations in Highly Dynamic Waters from Unattended Sensors and Remote Sensing Observations

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2699 ◽  
Author(s):  
Jian Li ◽  
Liqiao Tian ◽  
Qingjun Song ◽  
Zhaohua Sun ◽  
Hongjing Yu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Temporal Variations ◽  
Lake Area ◽  
Short Term ◽  
Chl A ◽  
Spatio Temporal

Monitoring of water quality changes in highly dynamic inland lakes is frequently impeded by insufficient spatial and temporal coverage, for both field surveys and remote sensing methods. To track short-term variations of chlorophyll fluorescence and chlorophyll-a concentrations in Poyang Lake, the largest freshwater lake in China, high-frequency, in-situ, measurements were collected from two fixed stations. The K-mean clustering method was also applied to identify clusters with similar spatio-temporal variations, using remote sensing Chl-a data products from the MERIS satellite, taken from 2003 to 2012. Four lake area classes were obtained with distinct spatio-temporal patterns, two of which were selected for in situ measurement. Distinct daily periodic variations were observed, with peaks at approximately 3:00 PM and troughs at night or early morning. Short-term variations of chlorophyll fluorescence and Chl-a levels were revealed, with a maximum intra-diurnal ratio of 5.1 and inter-diurnal ratio of 7.4, respectively. Using geostatistical analysis, the temporal range of chlorophyll fluorescence and corresponding Chl-a variations was determined to be 9.6 h, which indicates that there is a temporal discrepancy between Chl-a variations and the sampling frequency of current satellite missions. An analysis of the optimal sampling strategies demonstrated that the influence of the sampling time on the mean Chl-a concentrations observed was higher than 25%, and the uncertainty of any single Terra/MODIS or Aqua/MODIS observation was approximately 15%. Therefore, sampling twice a day is essential to resolve Chl-a variations with a bias level of 10% or less. The results highlight short-term variations of critical water quality parameters in freshwater, and they help identify specific design requirements for geostationary earth observation missions, so that they can better address the challenges of monitoring complex coastal and inland environments around the world.

Viruses in bottom sediments in a eutrophic reservoir (Ivankovo Reservoir, Upper Volga)

2015 ◽  
Vol 8 (3) ◽  
pp. 236-241 ◽  
Author(s):  
A. I. Kopylov ◽  
E. A. Zabotkina ◽  
A. V. Romanenko
Keyword(s):  
Bottom Sediments ◽  
Eutrophic Reservoir ◽  
Upper Volga ◽  
Ivankovo Reservoir

scholarly journals Bird trends from long-term observation data at sites in the Hudson Bay Lowlands

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Rodney W. Brook ◽  
Lisa A. Pollock ◽  
Kenneth F. Abraham ◽  
Glen S. Brown
Keyword(s):  
Hudson Bay ◽  
Observation Data ◽  
Hudson Bay Lowlands ◽  
Long Term Observation

scholarly journals Space-temporary variability of the winter minimum monthly runoff in the rivers of lake Sevan basin (Armenia)

2020 ◽  
Keyword(s):  
Water Discharge ◽  
Atmospheric Precipitation ◽  
Winter Period ◽  
Average Height ◽  
Observation Data ◽  
Flow Rates ◽  
Lake Sevan ◽  
Average Annual Runoff ◽  
Catchment Areas ◽  
Monthly Runoff

Formulation of the problem. The paper considers spatial-temporary variability of the winter minimum monthly flow rates of the rivers in the basin of Lake Sevan, as well as air temperature and atmospheric precipitation of the basin. The values of hydrological and statistical characteristics of the winter minimum monthly expenditure have been calculated. Purpose of the work is: to analyze and evaluate the patterns of temporal and spatial changes in the winter minimum monthly water discharge in a number of long-term observations for rivers that flow into Lake Sevan. Methods. The study is based on observation data from 12 hydrological posts of the “Service for Hydrometeorology and Active Impact on Atmospheric Phenomena” of the Ministry of Emergencies of the Republic of Armenia. The following methods were used for this purpose: mathematical-statistical, extrapolation, interpolation, analysis, analogy, correlation. Results. Minimum runoff is one of the main characteristics to be considered when designing hydraulic structures. Duration of winter low-water period is approximately 3-4–5 months on the rivers of the studied territory. It is established from late November – December to February – March. Minimum consumption is mainly found in January-February. However, in some years it is possible in November or March. Based on physical and geographical features of the area, the monthly winter minimum flow rates of the rivers of the Lake Sevan basin are characterized by uneven spatial distribution. Winter monthly minimum consumption ranges widely from 0.015 to 1.68 m3/s. Close correlations between the winter minimum monthly and the average runoff of the winter period and between the winter average minimum monthly runoff and the average annual runoff were also obtained. These relations can be used to obtain the winter minimum monthly consumption of unexplored and little studied rivers of the territory under discussion for a calendar year. A close relationship between them indicates that depending on the low minimum monthly runoff, the average runoff during the winter period is just as low, and vice versa. In the study area, there is a regular increase in the minimum runoff with an increase in catchment areas, as well as with an increase in the weighted average height of the catchment. The variation coefficient of winter minimum monthly consumption is 0.15–0.60 on the territory of the Lake Sevan basin and the asymmetry coefficient is from -0.64 to 1.77. As a rule, there is a regular decrease in the minimum runoff with an increase in catchment areas. The correlation directly proportional relationship has been obtained between the coefficients values of variation and asymmetry of the winter average minimum monthly flow. There is a tendency to an increase in winter average decade decimal consumption in most rivers flowing into Lake Sevan (7 out of 12 studied posts, that is, in 58% of cases) and an increase in air temperatures and precipitation at all currently operating meteorological stations in the basin.

scholarly journals SPECIFIC FEATURES OF WATER CHEMISTRY AND QUALITY IN THE LENA RIVER BASIN

2021 ◽  
Vol 26 (3) ◽  
pp. 33-43
Author(s):  
R. G. Dzhamalov ◽  
◽  
O. S. Reshetnyak ◽  
K. G. Vlasov ◽  
K. G. Galagur ◽  
...  
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Water Discharge ◽  
Surface Water Quality ◽  
Temporal Variations ◽  
Soil Freezing ◽  
Commercial Fishing ◽  
Lena River ◽  
Time Dynamics ◽  
Annual Water Discharge

Introduction. The Lena River is one of the largest rivers in Russia and the main transport artery of Yakutia. Methods. In the course of the study, we considered the water regime of the Lena River in 1981–2019 in relation to the monthly average water discharge. The hydrochemical runoff was quantitatively assessed based on the widely used landscape-hydrological method. The analysis made it possible to estimate the relationship between the natural water quality and the environmental state of catchments. Results. An increase in the winter temperature reduced the depth of soil freezing and increased the drainage properties of soil as well as the number and duration of winter thaws. The most pronounced annual water discharge was observed in the Aldan River basin in the eastern part of the Lena River basin. The current state of the surface water quality was assessed by the main hydrochemical characteristics: water salinity, principal ions (sulfates (SO4 2–)), nutrients (nitrite nitrogen (NO2–)), organic matter (BOD5 and COD), oil products, phenols, and iron (Fe) and copper (Cu) compounds. The water has quality class 3 and is characterized as “polluted” or “very polluted” in different zones of the river basin, with the situation being most acute in the Olekma River. Conclusions. We present the results of an analysis of the spatial and temporal variations in the content of the most informative hydrochemical components for two periods (2001–2009 and 2010–2019) in the Lena River basin in accordance with the most stringent commercial fishing standards in force. We also plotted and mapped the temporal variations in the main pollutants. Graphs and maps of the time dynamics of the main pollutants are constructed.

Large discrepancies on nitrate loading estimates from sparse measurements by SWAT and statistical models at catchment scale

2021 ◽  
Author(s):  
Kang Liang ◽  
Yefang Jiang ◽  
Fan-Rui Meng
Keyword(s):  
Water Quality ◽  
Agricultural Watershed ◽  
Data Availability ◽  
Accurate Estimation ◽  
Observation Data ◽  
Load Estimation ◽  
Concentration Data ◽  
Regression Methods ◽  
Nitrate Load ◽  
Sparse Measurements

<p>Nitrogen (N) is one of the major pollutants to aquatic ecosystems. One of the key steps for efficient N reduction management at watershed scale is accurate quantification of N load. High frequency monitoring of stream water N concentration has not been common, and this has largely been the limiting factor for accurate estimation of N loading worldwide. N loads have often been estimated from sparse measurements. The objective of this study was to investigate the performance of the physical-based SWAT (Soil and Water Assessment Tool) model and three commonly used regression methods, namely LI (linear interpolation), WRTDS (Weighted Regression on Time, Discharge, and Season), and the LOADEST (LOAD ESTimator) on estimating nitrate load from sparse measurements through a case study in an agricultural watershed in eastern Canada. The range of daily nitrate load of SWAT and LOADEST was 0.05-1.29 and 0.14 - 1.35 t day<sup>-1</sup>, compared with 0.13 - 13.08 t day<sup>-1  </sup>and 0.15 - 16.75 t day<sup>-1 </sup>for LI and WRTDS, respectively. Mean daily nitrate load estimated by the four methods followed the order: WRTDS > LI > LOADEST > SWAT. The large discrepancies were mainly occurred during the non-growing season during which there was observation data available. As regression methods use concentration data from dry seasons to estimate the concentrations of wet seasons, there is a strong likelihood of overestimation of nitrate load for wet seasons. The results of this study shed new light on nitrate load estimation under conditions of different data availability. Under situations of limited water quality measurement, policy makers or researchers are likely to benefit from using hydrological models such as SWAT for constituent load estimation. However, the selection of the most appropriate method for load estimation should be seen as a dynamic process, and case by case evaluation is required especially when only sparsely measured data is available. As agri-environmental water quality issues become more pressing, it is critical that data collection strategies that encompass seasonal variation in streamflow and nitrate concentration be employed in regions like Atlantic Canada in the future.</p>

Sign in / Sign up

Export Citation Format

Share Document