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Accumulation studies at specific sampling areas of the active floodplain in the Upper-Tisza region
Published August 23, 2017

In this paper the rate of accumulation was studied along four VO floodplain cross sections of the UpperTisza region between 1974 and 2014. VO floodplain cross sections are based on a mapping base-point grid (established in 1890), and they are located a few kilometers from each other. Furthermore, the roughness changes of different surface types..., crossed by the VO floodplain cross-sections, were also determined between 1965 and 2015. The accumulation studies were extended to include the accumulation rates of the cut off meanders located along and/or close to the VO cross-sections. The roughness values increased in all four floodplain VO cross-sections since 1965; in two of them it reached or approximated 100 %. The average accumulation along the VO cross-sections was between 28 and 47 cm (0.73–1.23 cm/year) during the 38-year period. However, its areal distribution showed large differences. The highest values (169–309 cm, i.e. 4.44–8.13 cm/year) were found at the lowest points of the cut off meanders and swales in every case. The accumulation rate of the examined three cut off meanders near the floodplain cross-sections (140 and 1570 meters from the river bed) was lower (0.84–2.5 cm/year), but the study period was significantly longer (154 and 161 years, respectively). Comparing the values of the two periods, it is obvious that the accumulation of the active floodplain accelerates, presumably due to the significant increase of surface roughness.

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Heavy metal content of flood sediments and plants near the River Tisza
Published December 31, 2008

The River Tisza is Hungary’s especially important river. It is significant not only because of the
source of energy and the value insured by water (hydraulical power, shipping route, stock of fish,
aquatic environment etc.) but the active floodplain between levees as well. Ploughlands, orchards,
pastures, forests and oxbow lakes can found here. They play a significant role in the life of the
people living near the river and depend considerably on the quality of the sediments settled by the
river. Several sources of pollution can be found in the catchment area of the River Tisza and some of
them significantly contribute to the pollution of the river and its active floodplain. In this paper we
study the concentration of zinc, copper, nickel and cobalt in sediments settled in the active floodplain
and the ratio of these metals taken up by plants. Furthermore, our aim was to study the vertical
distribution of these elements by the examination of soil profiles. The metal content of the studied
area does not exceed the critical contamination level, except in the case of nickel, and the ratio of
metals taken up by plants does not endanger the living organisms. The vertical distribution of metals
in the soil is heterogeneous, depending on the ratio of pollution coming from abroad and the quality
of flood.

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Morphological grouping of fossil floodplain forms in the northeastern part of the Pannonian plain
Published August 2, 2020

The Bereg Plain is located in the northeastern part of the Pannonian Plain, close to the Carpathian
Mountains. Clarification of the evolution of its topography is essential for the development of the whole
area. The former single alluvial cone has been fragmented, some parts of it subsiding and others rising.
The displacements of the s...ubsided parts of the area were dominated by erosion processes, as in the Bereg
Plain. As a consequence, a significant part of the sand in the area has been degraded and only traces of it
remain in the Bereg Plain. The existing sand patches have been identified and classified using DEM. In the
area identified 10 floodplain islands not yet mentioned in the scientific literature. The investigation of
the numerous islands – hitherto unknown and be-longing to different morphological types – enabled us a
reconstruction of the surface development of the Bereg Plain that is more differentiated and precise than
ever before. Based on their morphogenetic properties, these floodplain islands can be divided into three
main types: (1) erosion islands, (2) point-bars, (3) coastal dunes. In the area, I could recognize no pattern
or re-gularity in the position of the individual forms of any type. In many cases, the direction of the
longitudinal trends is perpendicular to one another, which excludes their Aeolian origin. The sediment
of the floodplain islands mainly consists of medium-, small- and fine-sized sand, but the settlement of
loess-mantled and loess-like layers among the sandy sediment of certain forms can also be observed. The
layer with 15 % lime content and 53–60 % loess fraction (0.05–0.01 mm) – found in the 110–50 cm high
section of the erosion island called the Homok-tanya in Mátyus – can be considered a typical loess, based
on the detailed parameters. Its formation in all probability took place at the same time and under similar
conditions than that of the more than 2 m thick aeolian loess mantle found in the Nyírség area, some 10
km west from there, which had accumulated before the Bölling period. In case of an erosion island 2.5
km to the south and lying some 2 m lower, such a loess mantle cannot be found anymore, despite the fact
that the sandy layers of the two sediment series are almost completely identical. The background of this
phenomenon is the more active and frequent, mainly erosional fluvial processes – because of the lower
position –, which eroded the loess mantle.
The composition of the surface sediments is de-termined by the absolute altitude as well. The cover
sediment of the lower-lying islands is identical to the finishing silt-clay deposits found at the alluvial
parts of the Bereg Plain, whereas the surface of higher-lying forms that have not seen flood for ages, is
covered by sand or loessy sand.

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Active point bar development and river bank erosion in the incising channel of the lower Tisza river, Hungary
Published December 20, 2019

The development of point-bars and bank erosion are critical near-bank processes, as they indicate
the sediment and hydraulic regime of a river system, thus, they refer to the equilibrium conditions of
a channel. However, throughout history, rivers have been modified for various benefits which change
the development of point-bars and th...e rate of bank erosion. In the Lower Tisza River (Hungary), river
regulations influenced the channel and floodplain development, altering the natural fluvial processes.
The aim of the research was to determine the rate of near-bank processes and to make trajectory for
future river evolution to support future engineering works. The bank erosion and point-bar development
at human-influenced and freely meandering sections of the Tisza River were monitored since 2011.
Behind a collapsed revetment, the bank erosion rate was 0.6 m/y, while at a freely meandering section it
was 2.3 m/y. The studied point-bars are located in revetted and freely meandering sections. Their surface
eroded within the period. These intensive erosional processes refer to an incising meandering channel,
which must be considered during future planning of in-channel structures (e.g. revetments, bridges),
thus, geomorphic methods must be considered in any river engineering scheme.

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Water chemical analysis of the oxbow lakes near the Upper-Tisza River
Published December 31, 2007

The Tisza river plays an important role in the life of Eastern Hungary. Beside the river there are several oxbow lakes, cut off meanders. In this paper the water quality of these lakes was examined from
the section of Tarpa to Rakamaz. 45 oxbow lakes were sampled and the chemical parameters were
determined. Sodium was used as a pollutant ...(sewage water) indicator and 2 lakes were found extremely polluted. The lakes outside the dam were slightly polluted because of the lack of renewal of
the water body and the ones in the active floodplain had good quality parameters.

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