scholarly journals Impact of the Danube River on the groundwater dynamics in the Kozloduy Lowland

2017 ◽  
Vol 46 (2) ◽  
pp. 33-39
Author(s):  
Peter Gerginov

Intense groundwater flow in the Kozloduy Lowland is related to the formed layered aquifer on the contemporary Danube River terrace. The main factors affecting the groundwater regime are fluctuations of the Danube River, water influx from the south and the recharge as a part of the rainfalls in the area. The drainage system in the central part of the lowland affects the water levels and creates a widespread depression. This forms a disturbed groundwater regime in the area. The impacts of the Danube River for a six-year period (from 2007 to 2012) have been estimated. The groundwater balance elements were analyzed, based on transient numerical model of the lowland. Fluctuations of the groundwater levels are the most significant close to the river at a distance of 300–400 m, reaching as much as 1000 m in the lowland. Oscillation’s amplitude of groundwater levels gradually decreases with distance from the river and as a result of the drainage system abstraction. There is relation between the water stages in the river and the intensity of the drainage flow.

Author(s):  
Y.A. Romanova ◽  
Zh.R. Shakirzanova ◽  
E. D. Gopchenko ◽  
I.S. Medvedieva

Katlabukh Lake is a part of the Danube Lakes system and is one of the surface water sources for water supply, for agricultural needs and irrigation of the region. Changing the conditions of operation and regulation of the reservoir led to a decrease of water levels and an increase of salinity, which makes it impossible to use water for different management needs. Calculations of the water and salt regimes of the lake based on the solution of the equation of balance said that in the water balance of Katlabukh Lake the main volume of the revenue part for the period 1980-2018 was precipitation (36.1%) and water inflow from the Danube River (38%), and the expenditure part – evaporation together with transpiration (50.5%). Salt flow into the lake is mainly due to surface inflow (53.4%) and water of the Danube River (25.5%), and loss of irrigation (45.1%) and water discharges to the Danube River (31.9%). Simulation modeling of the water-salt regime of the Katlabukh lake under different conditions of exploitation of the reservoir showed that corrective management measures are needed to improve the qualitative indicators of the water in the reservoir. They consist in the fact that for three summer months it is necessary to carry out forced pumping of poorly mineralized water from the Danube River to compensate for evaporation from the water surface (on average in volumes of the order of 55 million m3) or to carry out fences of water from the lake for irrigation in 60 million m3. This will allow to reach the design values of water mineralization in the lake equal to 1.0-1.5 g/dm3. Thus, addressing a range of problems to conserve and restore the rational use of the natural resources of Katlabukh Lake requires effective managerial water management activities that require additional feasibility studies.


2021 ◽  
Vol 906 (1) ◽  
pp. 012101
Author(s):  
Veronika Bacová Mitková

Abstract The territory of the Danube River Basin is one of the most flood-endangered regions in Europe. The flow regime conditions of the Danube River are continually changing. These changes are the result of natural processes and anthropogenic activities. In the present study, we focused on the statistical analysis and trend detection of the hydrological extremes of the Danube River at Bratislava. This paper firstly analyses the changes in correlation between water levels of the Danube River at Bratislava and Kienstock. Studied period of 1991-2013 included one or three hour measured water levels of the Danube River at Bratislava and Kienstock and shorter periods (1991–1995, 1999–2002, and 2004—2013) were selected for identification of the water level changes at Bratislava. One of the factors that recall the necessity to establish empirical - regression relationships was increasing of water levels of the Danube River at Bratislava (due to sediments accumulation at Bratislava). The results of the analysis indicated an increasing of water levels corresponding to the same flood discharges observed in the past. We also can say that travel time of the Danube floods between Kienstock and Bratislava did not change significantly during the analysed period. In the second part of the paper, we have identified changes in commonly used hydrological characteristics of annual maximum discharges, annual discharges and daily discharges of the Danube River at Bratislava during the period of 1876–2019. We examined whether there is a significant trend in discharges of the Danube River at Bratislava.


Author(s):  
Yavuz Karsavran ◽  
Tarkan Erdik

Sea level prediction is an important phenomenon for making reliable oceanographic and ship traffic management decisions especially for Bosphorus Strait that has no permanent sea level measurement stations due to high cost. This study presents artificial intelligence (AI) techniques, such as Artificial Neural Networks (ANNs) and Support Vector Machines (SVM) to predict the seawater level in the Bosphorus Strait. In addition, the Multiple Linear Regression model (MLR) is constructed and employed as a benchmark. The dataset employed in developing the models are wind speed, atmospheric pressure, water surface salinity, and temperature data, which were measured between September 2004 and January 2006. The results reveal that all ANN and SVM models outperform MLR and can predict the water levels quite accurately. ANN has a better performance than SVM for predicting sea level in the Bosphorus by coefficient of correlation (R) = 0.76 and root mean square error (RMSE) = 0.059. Moreover, the influence of the Danube River discharge in the prediction is investigated in the present study. The discharge of the Danube River by the lag time of 70 days yields the highest performance on ANN by increasing R to 0.82 and decreasing RMSE to 0.048.


2020 ◽  
Vol 26 (1) ◽  
pp. 94-109
Author(s):  
П.С. Суворов ◽  
◽  
Т.В. Тарасенко ◽  
В.И. Залож ◽  
◽  
...  

The issues of energy efficiency assessment for inland navigation vessels and focus on the need to implement different approaches in this context in relation to single vessels against pushers with heavy convoys are considered. This is due to transportation technologies, which have a number of significant differences when pushing a heavy caravan. The analyses were made for the data of systematic testing of ships and the values of energy efficiency indicators obtained for them according to the methodology applied by IMO for ships in international maritime shipping. Fluctuations in water levels on inland waterways and on river sections, in particular, especially when moving pushers with caravans of barges, have a significant impact on the performance of the hydrodynamic propulsive complex. Using the example of the data from the Danube river gauging stations, the assuring enough depth both when performing one voyage at different sections of movement, and during a calendar year were considered. The ratios of the fairway depth and the draft of the vessel are determined, which are boundary for a decrease in the speed of movement in connection with a change in resistance with a tangible negative effect of shallow water. In this regard, issues of increasing fuel consumption in shallow water areas and related factors affecting energy efficiency are also considered. At the same time, the interrelation of energy efficiency and eco-friendliness dictates the use of integrated approaches not only from the standpoint of quantitative indicators of fuel consumption, but also from the standpoint of the use of modern technologies for cleaning exhaust gases. The factors contributing to the development of energy efficiency management are considered as separate categories. These include the work of the River Information Services (RIS), the training of river boatmasters and the instability factors in the shipping and bunker markets. The conclusions about the inseparability of the considered factors, as well as the need for their further comprehensive consideration in order to create a common algorithm for managing energy efficiency in the inland navigation were made.


Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 1017-1028 ◽  
Author(s):  
P P Povinec ◽  
Z Ženišová ◽  
A Šivo ◽  
N Ogrinc ◽  
M Richtáriková ◽  
...  

Horizontal and vertical variations in the distribution of 14C, δ13C, δ18O, and δ2H in groundwater of Žitný Island (Rye Island) have been studied. Žitný Island, situated in the Danube River Basin, is the largest island in Europe that is formed by interconnected rivers. It is also the largest groundwater reservoir in central Europe (∼1010 m3 of drinking water). The δ2H vs. δ18O plot made from collected groundwater samples showed an agreement with the Global Meteoric Water Line. In the eastern part of the island, it was found that subsurface water profiles (below 10 m water depth) showed enriched δ18O levels, which were probably caused by large evaporation losses and the practice of irrigating the land for agriculture. The core of the subsurface 14C profile represents contemporary groundwater with 14C values >80 pMC, indicating that the Danube River during all its water levels feeds most of the groundwater of Žitný Island. However, on the eastern part of the island a small area was found where the δ13C and 14C data (down to ∼30 pMC) helped to identify a groundwater aquifer formed below the Neogene clay sediments. This is the first time that vertical distributions of isotopes in different groundwater horizons have been studied.


2014 ◽  
Vol 17 (2) ◽  
pp. 48-51
Author(s):  
Miroslava JARABICOVÁ ◽  
Mária PÁSZTOROVÁ ◽  
Justína VITKOVÁ ◽  
Peter MINARIČ

Abstract Rye Island is a unique natural formation, which lies between the main flow of the Danube River and the Little Danube River and is the largest river island in Europe. It is located in the southwest of Slovakia and with its mild to slightly warm climate is one of the most fertile agricultural areas in Slovakia. The whole Rye Island is also our greatest reservoir of quality waters used for drinking purposes, where groundwaters of Rye Island are permanently supplied with water from the Danube River. It means that as water levels in the Danube River were unstable before the construction of the Gabčíkovo Water Project, also the groundwater level faced large fluctuations. Changes occurred after putting the Gabčíkovo Water Project into service, with a decrease in groundwater levels. Thereby, the conditions for agriculture have improved and drying of surrounding protected floodplain forests has stopped. Through the present contribution we decided to analyse the impact of Gabčíkovo on soil water regime in the area of Rye Island, and evaluate the course of groundwater level, precipitation and soil water storage over time. For the representative area we chose a forest ecosystem of Král’ovská Lúka and evaluated the period 1999 to 2009.


2020 ◽  
pp. 102-115
Author(s):  
Zh. R. Shakirzanova ◽  
N. S. Kichuk ◽  
Yе. О. Romanova ◽  
I. D. Kichuk ◽  
Iu. S. Medvedieva

Introduction. This investigation aims at studying the individual components of the hydrological and hydrochemical regimes of the Danube River (within Ukraine) in connection with the widespread use of the river's water for water supply and irrigation in the southern region, as well as to ensure more effective regulation of water-salt regime of the Danube lakes using the Danube River as a main source for their water renewal. One of important aspects includes the study of the regime of the Danube River's suspended sediments brought to its delta due to their impact on the formation of the delta at the river's mouth of as well as due to the impact on siltation of deltaic and pre-delta lakes and canals connecting the lakes with the Danube River. Purpose. The purpose of the work is to study long-term and current trends related to changes in hydrological (water levels and discharges, suspended sediments runoff) and hydrochemical (mineralization) regimes of the Danube River within the Ukrainian interval from Reni to Izmail, internal annual distribution of water runoff, as well as suspended sediments runoff and mineralization during the years of varying water content.  Results. The statistical analysis of long-term series of observations over the Danube River within the interval from Reni to Izmail resulted in discovering that time trends of average, maximum and minimum water levels (1921-2015) and discharges (1840-2015) indicate the presence of a weak increase in their growth over time, with a more pronounced increase in maximum water levels or discharges. The annual distribution shows the general synchronicity of fluctuations in runoff characteristics, and the maximum monthly values of water discharge differ have more pronounced seasonal fluctuations. The study shows the presence of a pronounced trend to reduction of suspended sediments runoff of the Danube River at Reni (for the period of 1840-2015), with their most intensive decrease over the period of 1990-2015. Annual distribution of average monthly suspended sediments runoff of the Danube River for the years with typical water content (for the period of 1978-2015) showed that they have seasonal fluctuations. At the same time, there is a decrease in the suspended sediments runoff along the length of the river from Reni to Izmail. The long-term course of average annual mineralization values of the Danube River at Izmail (1981-2015) is characterized by their decrease against the background of a small increase in average annual discharges. As per the annual distribution of mineralization values associated with all water content groups there are the periods related to the phases of the river's yearly water regime during and the economic use of water. Conclusion. Thus, the increase in the long-term period of the Danube River runoff within the interval from Reni to Izmail will contribute to the development of the region's economy and water supply, irrigated farming, regulation of the Danube Lakes filling with weakly mineralized river water. At the same time, the reduction of the suspended sediments runoff will restrain the siltation of the inlet canals connecting the lakes with the Danube River, which will improve the water renewal of the lakes with the river's fresh waters.


Author(s):  
E. M. B. Sorensen ◽  
R. R. Mitchell ◽  
L. L. Graham

Endemic freshwater teleosts were collected from a portion of the Navosota River drainage system which had been inadvertently contaminated with arsenic wastes from a firm manufacturing arsenical pesticides and herbicides. At the time of collection these fish were exposed to a concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to 20.0 ppm during the four-month period prior. Scale annuli counts and prior water analyses indicated that these fish had been exposed for a lifetime. Neutron activation data showed that Lepomis cyanellus (green sunfish) had accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major detoxification organ in arsenic poisoning. Examination of livers for ultrastructural changes revealed the presence of electron dense bodies and large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as previously observed in this same species following laboratory exposures to sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas (NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies (FB) were observed. In order to assess whether the extent of these cellular changes was related to the concentration of arsenic in the liver, stereological measurements of the volume and surface densities of changes were compared with levels of arsenic in the livers of fish from both Municipal Lake and an area known to contain no detectable level of arsenic.


2016 ◽  
Author(s):  
Danica Ciric ◽  
Milica Stojanovic ◽  
Anita Drumond ◽  
Raquel Nieto ◽  
Luis Gimeno

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