Lower Tisza Research Articles

Increased Riparian Vegetation Density and Its Effect on Flow Conditions

The physical and biological structure of riparian vegetation fundamentally influences floodplain roughness, and thus the flood velocity and flood levels of a river. The study aims to provide detailed spatial data on the vegetation density of a floodplain, and to model the effect of the actual vegetation and various scenarios on flow conditions. LiDAR data were applied to evaluate the density and roughness of the submerged understory vegetation over the densely vegetated floodplain of Lower Tisza, Hungary. Then, HEC–RAS 2D modelling was applied to analyse the effect of the actual vegetation on flow conditions. Further scenarios were also created to predict the effect of (i) invasive plant control, (ii) no maintenance, and (iii) riparian vegetation restoration (meadows). According to the results, since the 19th Century, the increased vegetation density is responsible for a 17-cm flood level increase, and if the vegetation grows even denser, a further 7 cm could be expected. As the vegetation density increases, the overbank flow velocity decreases, and the crevasses and flood conveyance zones gradually lose their function. Simultaneously, the flow velocity increases in the channel (from 1 m/s to 1.4 m/s), resulting in an incision. Applying LiDAR-based 2D flow modelling makes it possible to plan sustainable riparian vegetation maintenance (e.g., forestry, invasive species clearance) from both ecology and flood control perspectives.

Mapping subsurface defects and surface deformation along the artificial levee of the Lower Tisza River, Hungary

Artificial levees along alluvial rivers are major components of flood-risk mitigation. This is especially true in the case of Hungary, where more than one-third of the country is threatened by floods and protected by an over 4200-km-long levee system. Most of such levees were built in the nineteenth century. Since then, several natural and anthropogenic processes, such as compaction and erosion, might have contributed to these earth structures' slow but steady deformation. Meanwhile, as relevant construction works were scarcely documented, the structure and composition of artificial levees are not well known. Therefore, the present analysis mapped structural differences, possible compositional deficiencies, and sections where elevation decrease is significant along a 40-km section of the Lower Tisza River. Investigations were conducted using real-time kinematic GPS and ground-penetrating radar (GPR). Onsite data acquisition was complemented with an analysis using a Persistent Scatterer Synthetic Aperture Radar to assess general surface deformation. GPR profiles showed several anomalies, including structural and compositional discontinuities and local features. The GPR penetration depth varied between 3 and 4 m. According to height measurements, the mean elevation of the levee crown decreased by 8 cm in 40 years. However, the elevation decrease reached up to 30 cm at some locations. Sections affected by structural anomalies, compositional changes, and increased surface subsidence are especially sensitive to floods when measurement results are compared with flood phenomena archives.

Avar and Árpádian Age Populations along the Maros River

Review article of a PhD thesis submitted in 2022 to the Archaeological Doctoral Programme, Doctoral School of History, Eötvös Loránd University, Budapest, under the supervision of Miklós Takács.The research behind the dissertation comprises a basic large-scale evaluation of the material record of primarily Avar Period (7–9th-century) settlements. The study area is located in the Lower Tisza Region and the southern part of the Körös-Maros Interfluve, including the southern part of the Southern Tisza Valley and the entire Marosszög microregion, north of the River Maros, on the lands between Szeged-Öthalom and Csanádpalota/Nagylak.

Spatial Variations in Microfiber Transport in a Transnational River Basin

Five countries share the catchment of the Tisza River (Central Europe). In most households electricity and water are available, and by washing synthetic clothes they can produce a large number of microfibers. However, in many sub-catchments of the river, the wastewater treatment is insufficient; therefore, microplastics (MP), especially plastic microfiber emissions into rivers, represent a problem. Our goal was to analyze the suspended sediment and microfiber transport at the low stage, making repeated (2021 and 2022) measurements in the Tisza River (946 km) at 26 sites across three countries. Water sampling was performed by pumping 1 m3 of water through sieves (90–200 µm). The mean MP transport in 2021 was 19 ± 13.6 items/m3, but it increased by 17% in 2022 (22.4 ± 14.8 items/m3). The most polluted sections were the Upper Tisza (Ukraine, Hungary) and the Lower Tisza (Serbia), where wastewater treatment is not satisfactory, whereas the Middle Tisza (Hungary) was less polluted. The tributaries increased the sediment and MP budget of the main river. Microfibers dominate (84–97%) the suspended MP transport, and thus it can be determined that they originated from wastewater. The MP transport was influenced by the availability of wastewater treatment plants, dams, tributaries, and mobilization of bottom sediments. At the low stage, no connection was found between the suspended sediment and MP particle transport.

Ártéri üledékek mikroműanyag tartalma az Alsó-Tisza egy kanyarulata mentén

Plastics get into the environment legally or illegally, and their amount is increasing continuously because their usage is constantly increasing. Microplastics (< 5 mm) have several morphological types: fragments can be formed by physical weathering of larger plastic objects; fibres usually originate from washing synthetic clothes; while pearls used in cosmetics get into the environment by means of communal waste. Our aim is to analyse the sedimentation pattern of microplastics on various floodplain forms along a natural meander of the Lower Tisza River, Hungary. The uppermost sediment layer (0–5 cm) of the floodplain forms contains 0–1800 microplastics/kg. The sediments of the swales (458–1300 particles/kg) and the point bar sediments (220–1600 particles/kg) are the most polluted, but the samples from the low-lying clay pits are also highly contaminated (818–880 particles/kg). The active point bar and the natural levee have lower levels of microplastic contamination (100–620 particles/kg). In the natural levee along the channel, microplastics are present to a depth of 50 cm (1753–4800 particles/kg), while in the distal parts of the floodplain only the upper 0–10 cm sediment layer is polluted. Plastic fibres are the most common plastic types in the samples, clearly indicating that they originate from treated or untreated wastewater.

Assessing the structure and composition of artificial levees along the Lower Tisza River (Hungary)

Levees are earth structures constructed along alluvial rivers and are considered to be one of the essential components of flood risk and natural hazard reduction. The preservation of their condition would require orderly monitoring. In Hungary, an over 4200 km long levee system was constructed from the 19th century on. Since then, many natural and anthropogenic processes, such as compaction, erosion, subsidence etc., could contribute to the slow but steady deformation of these structures. In the meantime , due to the lack of documentation, their structure and internal composition are still unclear in many sections. The present study uses different geophysical techniques to validate their efficiency in detecting the structure, composition and potential defects along a 3.6 km levee section of the Lower Tisza River, affected significantly by seepage and piping phenomena during floods. Measurements were made using Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and drillings. Information obtained by the different techniques was cross-checked and combined. This way, the potential of the applied survey strategy could be demonstrated, and the selected levee section could be assessed in terms of its structure and composition. Consequently, the major reasons for frequently occurring adverse flood phenomena at the site could be revealed. The survey approach outlined in the present paper can be applied extensively along lowland levee systems in the region and elsewhere.

Increased flood height driven by local factors on a regulated river with a confined floodplain, Lower Tisza, Hungary

On artificially confined floodplains, various active processes influence the local peak flow level. However, these active processes are often neglected in flood management because calculations are based on static parameters. The aim of this study is to analyse the processes that contribute to rising local flood levels in a regulated channel and on an artificially confined floodplain of a lowland river. Our goals were to evaluate the role of cross-sectional channel changes, overbank floodplain aggradation, and riparian land-cover changes on local flood level increases since the late nineteenth century and early twentieth century and to assess the height changes of artificial levees. The research was performed in a low-gradient river (Lower Tisza, Hungary), which was regulated in the late nineteenth century; thus, the effects of century-long processes on flood levels could be evaluated. The results suggest that along the 92 km-long reach, the channel was narrowed by 9% and its cross-sectional area decreased by an average of 2%; however, the narrowing was over 30% in some locations. Because of these changes, flood levels increased by an average of 13 cm (maximum = 134 cm) since 1931. Because the artificial levee was constructed in the mid-nineteenth century, the mean overbank floodplain accumulation reached 1.2 m (maximum = 2.6 m), flood levels decreased by an average of 112 cm. During the same period, the land cover of the floodplain changed considerably, increasing the vegetation roughness (i.e., Manning's n) from 0.048 to 0.11. Based on our modelled data, the higher vegetation roughness increased flood levels by 42 cm (Scenario A) or 139 cm (Scenario B), on average, based on the increased vegetation roughness (by 10% or 30%, respectively). By overlapping these data, the results showed that since the river regulation work in the late nineteenth century, the actual flood level increased by an average of 175 cm (maximum = 350 cm) in the case of Scenario A and 272 cm (maximum = 443 cm) in the case of Scenario B. The latter is more consistent with the actual flood stage measurements. As these processes are still active, further increases in the flood level could be expected. In addition, the height of artificial levees decreased by an average of 23 cm (maximum = 75 cm); thus, some levee sections became more susceptible to overtopping during record high floods, especially along the eastern levee. Based on this approach, local hydrological managers can identify the processes that contribute more to peak flow level increases at a given location and determine the correct actions at the correct locations, which could lead to decreases in peak flow levels.

Identification of Riparian Vegetation Types with Machine Learning Based on LiDAR Point-Cloud Made Along the Lower Tisza’s Floodplain

Abstract The very dense floodplain vegetation on the artificially confined floodplains results in decreased flood conveyance, thus increase in flood levels and flood hazard. Therefore, proper floodplain management is needed, which must be supported by vegetation assessment studies. The aims of the paper are to introduce the method and the results of riparian vegetation classification of a floodplain area along the Lower Tisza (Hungary) based on automatized acquisition of airborne LiDAR survey. In the study area 15x15 m large training plots (voxels) were selected, and the statistical parameters of their LiDAR point clouds were determined. Applying an automatized parameter selection and 10-fold cross-validation he most suitable decision tree was selected, and following a series of classification steps the training plots were classified. Based on the decision tree all the pixels of the entire study area were analysed and their vegetation types were determined. The classification was validated by field survey. On the studied floodplain area the accuracy of the classification was 83%.

Point-bar development under human impact: Case study on the Lower Tisza River, Hungary

Point-bar development under human impact: Case study on the Lower Tisza River, Hungary

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

The development of point-bars and bank erosion are critical near-bank processes, as they indicatethe sediment and hydraulic regime of a river system, thus, they refer to the equilibrium conditions ofa channel. However, throughout history, rivers have been modified for various benefits which changethe development of point-bars and the rate of bank erosion. In the Lower Tisza River (Hungary), riverregulations 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 forfuture river evolution to support future engineering works. The bank erosion and point-bar developmentat 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 itwas 2.3 m/y. The studied point-bars are located in revetted and freely meandering sections. Their surfaceeroded 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.

Bank Processes and Revetment Erosion of a Large Lowland River: Case Study of the Lower Tisza River, Hungary

Stone and concrete revetments are widely constructed to control bank erosion and thus stabilize river banks. The consequences include accelerated erosion at unrevetted downstream channel sections and in-channel incision at revetted sections. The studied section of the Tisza River (Hungary) was revetted along 49% of its banks in the 20th century with stepped-block and placed-rock revetments. We therefore aimed (1) to study the effects of revetment constructions on channel processes and (2) to evaluate the state and collapse of revetments using a DEM of the channel and ADCP measurements. In the late 19th century, the river had an equilibrium meandering channel, with alternating eroding and aggrading banks. Currently, erosional processes dominate. Thus, 65% of the total channel length is affected by bank erosion. The revetments reduced the active lateral erosional processes only temporarily, as 58% of the revetments, mainly placed-rock, are already damaged. The flow characteristics at the revetted sections were found to depend on the rate and type of revetment collapse. Large pools developed in front of the revetments, playing an important role in initiating their erosion. The placed-rock revetments can collapse by slides or by stones falling into the pool one-by-one. In this case, a knickpoint develops, propagating upstream. Thus, the collapse and accelerated bank erosion also propagate upstream. The increased hazard created by the failure of the revetments requires the re-planning of bank stabilization practices.

Long-term hydrological changes after various river regulation measures: are we responsible for flow extremes?

Abstract Engineering works have affected the morphology of rivers (e.g., by cut-offs, artificial levees, revetments, and reservoir and dam constructions). These human impacts also have hydrological impacts, as they alter the natural channel geometry, affect the carrying capacity of the channel and confine the floodplains. The goals of the present paper are to analyse flow changes for the Tisza River (in Hungary) with its highly regulated channel using a long (141 y) daily hydrologic dataset and to evaluate the engineering works from the point of hydrological and morphological equilibrium. Since the late 19th century, the flood level along the Lower Tisza River has increased by 216 cm; further, since 1998, flood levels increased by over 80 cm without an increase in discharge. In addition, river stages for low flows have decreased, and the water slope has decreased. These changes are likely connected to morphological changes in the channel (e.g., incision, narrowing, disappearance of point bars, intensifying mass movements), which have been driven by the complex response to human impacts. While the channel could adjust itself to convey larger floods after the cut-offs, the revetments impede the channel adjustment and contribute to the hydrological and morphological disequilibrium state along the Tisza River.

Changes in Floodplain Vegetation Density and the Impact of Invasive Amorpha fruticosa on Flood Conveyance

Abstract Flood conveyance of floodplains is significantly influenced by the riparian vegetation cover, since vegetation affects flow velocity, therefore has a considerable impact on flood height and rate and pattern of sedimentation. However, climate change promotes the spread of invasive species, and their rapid growth results in dense vegetation stands, thus they have a significant impact on floodwater hydraulics. The aims of the present study are (1) to analyse the long-term changes in land-use and vegetation density on the Lower Tisza River, (2) to evaluate the role of the invasive Amorpha fruticosa in increasing vegetation density, and (3) to model the effect of dense floodplain vegetation on flood level and flood conveyance. Long-term (1784-2017) changes of land-use suggest that in natural conditions the study area was occupied by wetlands (92%), thus water covered the area for almost the whole year. In the 19th century, after levee constructions the wetlands were replaced by meadows and pastures (94%), then by the end of the 20th century planted and riparian forests replaced these land-covers. As a result, the mean roughness (0.14) of the floodplain has increased threefold until the early 21st century. Today forests are invaded by Amorpha fruticosa, which increases the vegetation density by 3% in riparian forests, by 23% in forest plantations, and by up to 100% in abandoned pastures and a rable lands. According to the results of HEC-RAS (Hydrologic Engineering Center’s River Analysis System) and CES (Conveyance Estimation System) models, if floodplain vegetation was managed and Amorpha fruticosa was cleared from the floodplain, peak flood level would decrease by 15 cm. Due to dense vegetation, the flood conveyance decreased by 4-6%, and the presence of Amorpha fruticosa reduced the flood flow velocities by 0.014-0.016 m/s. Accordingly, clearance of the floodplain from Amorpha fruticosa would have positive effects on flood protection, since peak flood stages would decrease and flood waves would shorten.

Morphological Evolution of the Lower Tisza River (Hungary) in the 20th Century in Response to Human Interventions

To understand the hydro-morphological responses of a river to engineering works is a key to future sustainable engineering projects. The Tisza River in the Carpathian Basin has been the subject of human interventions in the 19th–20th centuries, with regular monitoring since the first intervention. Therefore, it provides a unique opportunity to understand the long-term responses of a lowland river on engineering works. Here the interventions include the construction of embanked levees, artificial meander cutoffs, construction of revetments and groynes, and construction of lock-dams, whose differing effects can be analysed in detail. The Lower Tisza River, Hungary was shortened by up to a third of its 89-km length during late-19th-century regulation works. Simultaneously, it was disconnected from its 10–20 km wide natural floodplain, which was restricted to 1–5 km. Revetments were constructed along 25% of the banks since the early 20th century. This paper evaluates the effects of these regulation works on the Lower Tisza channel based on channel-surveys (1891, 1931, 1961, 1976 and 1999). Based on the results, the channel responded to every stage of the regulation works by adjusting its cross-sectional area, thalweg depth and bankfull width. From 1891 to 1961, the cross-sectional area of the channel increased in response to the artificial meander cutoffs through rapid incision and channel widening. The construction of revetments and groynes distorted this morphological development. After their construction, the cross-sectional area of the channel reduced by up to 50% between 1961 and 1976. The channel experienced incision and narrowing within this period. Whilst the morphological response of the river to cutoffs was improved flood conveyance, the revetments drastically decreased the flood conveyance; therefore, the flood levels increased without an increase in discharge, so the revetment constructions indirectly increased the flood risk.

Centurial Changes in the Depth Conditions of a Regulated River: Case Study of the Lower Tisza River, Hungary

Abstract The Tisza River is the largest tributary of the Danube in Central Europe, and has been subjected to various human interventions including cutoffs to increase the slope, construction of levees to restrict the floodplain, and construction of groynes and revetments to stabilize the channel. These interventions have altered the natural morphological evolution of the river. The aim of the study is to assess the impacts of these engineering works, employing hydrological surveys of 36 cross sections (VO) of the Lower Tisza River for the years of 1891, 1931, 1961, 1976 and 1999. The changes in mean depth and thalweg depth were studied in detail comparing three reaches of the studied section. In general, the thalweg incised during the studied period (1891-1931: 3 cm/y; 1931-1961: 1.3 cm/y and 1976-1999: 2.3 cm/y), except from 1961-1976 which was characterized by aggradation (2 cm/y). The mean depth increased, referring to an overall deepening of the river during the whole period (1891-1931: 1.4 cm/y; 1931-1961: 1.2 cm/y; 1961-1976: 0.6 cm/y and 1976-1999: 1.6 cm/y). The thalweg shifted more in the upper reach showing less stabile channel, while the middle and lower reaches had more stable thalweg. Although the cross-sections subjected to various human interventions experienced considerable incision in the short-term, the cross-sections free from direct human impact experienced the largest incision from 1891-1999, especially along the meandering sections.

Der Fund von Ada

Numerous finds, excavated from the probably isolated grave along the Lower Tisza, were taken to the Vojvođanski Muzej (Novi Sad, Serbia). The grave can be dated unambiguously to the second half of the 8th century. Drawing a parallel between the silver cup and the 8th-century dish of the Nagyszentmiklós treasure has a considerable significance both for the chronologic and cultural identification of the latter, and for the Avar-Age chronology of tendril decoration with punched background as well. Accordingly, this decoration had been around already in the 7th century, which is an equally important condition for the chronology of the late Avar Period, and especially for the research of the question of continuity between the middle and late periods.

Anglers’ Perceptions and Fish Consumption Risks in the Lower Tisza River Basin

This study identifies risk perception and actual health risks from exposure to metals in fish from the Tisza River Basin of central Europe. Mining in the region has chronically introduced metals; however, two major mine-tailings spill in 2000 contributed an estimated 240,000 m3 of wastewater and tailings contaminated with cyanide and metals to the system. In 2013 and 2014, water and fish (N = 99) collected from the lower Tisza River Basin were analyzed for cadmium, copper, lead, nickel, and zinc. Concurrently, surveys (N = 45) collected near sampling sites assessed fish-consumption patterns and risk perception. Metals in water exceeded regulatory criteria at multiple sites; however, metals are not bioaccumulating to a degree of undue concern in fish as bioaccumulation factors were below 1. Average concentrations of metals in fish fillets (µg g−1 wet weight) in decreasing order were zinc (8.8) > copper (0.14) > nickel (0.06) > lead (0.02) > cadmium (0.004). Fillets were within European Food Safety Authority recommendations; however, the Target Hazard Quotient for lead was elevated at 1.5 for average consumers and 3.5 for people who consume fish twice weekly. The majority of survey participants were unconcerned with local fish consumption (87 %), citing the “clean” appearance of fishing locations. Participants also reported relatively low fish consumption, with most (76 %) eating basin fish once a week or less. While our study indicates fish are generally safe for human consumption, waters are polluted, suggesting that local fishing populations may be at risk from unseen pollutants and highlighting the need for monitoring and notification systems.

Modelling the Hydrological Effects of a Levee Failure on the Lower Tisza River

Abstract Along the Lower Tisza River (Hungary) the water level of the floods reached new record stages in 1998 and 2006, resulting in 80 cm increase in the peak flood level since the “great flood of 1970”. Due to the gradual weakening of the levee-system caused by the several long-lasting floods, the question has arisen, that as in case of a levee breach or failure how would it modify the hydrological parameters of the river. The aim of the research is to create a hydrological model to analyse the effects (as stage reduction, slope and stream power) of two different levee breaches: one happening before the peak of the flood and another at the time of the flood level. The simulated levee breaching happened on the Tisza River at Mindszent, and the data-set of the 2006 flood was used for the modelling (at that time no levee failure happened in Hungary, and it was the greatest flood in history). In the simulation the levee was broken at a point, where the channel is very close and intensively eroding, thus there is a real risk of a levee failure. If the levee would be broken a well defined area (reservoir) would be flooded, surrounded by the secondary levees and the rim of the high floodplain. During the simulation the HEC-RAS 4.1. ArcGIS 10.1 and HEC-GeoRAS software were applied. The greatest changes in the hydrology of Tisza occurred in the cross section where the levee breached, though the effects propagated upstream and downstream too. Due to the water outflow from the Tisza the greatest stage reduction effect was 1.54±0.1 m. The slope conditions changed too, as it increased from 4 cm/km to 6.5 cm/km in the upstream reach, while downstream of the failure point it decreased from 3.5 cm/km to 1.9 cm/km. At the same time the stream power increased from 4 W/m to 5.5 W/m in the upstream section, while it decreased from 3.5 W/m to 1.5 W/m in the downstream reach. Comparing the results of the simulations at different stages (one at the highest stage and one at 1.0 m lower stage) it seems that the hydrological parameters did not change considerably (1%), though in a case of a levee failure at higher the reservoir reached the maximal water level sooner, though less water was stored in it, as the fall of the river was continuous

Strategic floodplain reconnection for the Lower Tisza River, Hungary: Opportunities for flood-height reduction and floodplain-wetland reconnection

Summary During the late 19th Century, the Tisza River’s vast floodplain-wetland system was largely disconnected by levees, facilitating “reclamation” for agriculture and resulting in an estimated loss of over 90% of historical wetlands. While levees have been successful in preventing catastrophic flooding for a century, Lower Tisza flood stage records have been set repeatedly during the last 15 years. The decrease in the Tisza’s current floodway carrying capacity has reduced the flood-protection level of the Tisza’s aging levee system. Recently in Hungary, “Room for the River” policies have gained more prominence. To explore the possibilities of a room for the river approach along the Lower Tisza, we assess eight potential floodplain-reconnection scenarios between Csongrad, Hungary and the Hungary–Serbia border. A novel framework using hydrodynamic and geospatial modeling was used to perform planning-level evaluations of the tradeoffs between floodplain-reconnection scenarios and enhancement of the existing levee system. The scenarios evaluated include levee removal and levee setbacks to strategically reconnect significant historical wetlands while reducing flood levels. Scenario costs and human population impacts are also assessed. Impacts of reconnecting the Lower Tisza floodplain are compared to heightening levees, the prevailing strategy over the previous century. From a purely construction-cost perspective, heightening Lower Tisza levees is potentially the most cost-effective and politically expedient solution (i.e., impacts the least number of people). However, levee-heightening does not solve the long-term problem of reduced flood conveyance, which has been attributed to aggradation and increased floodplain roughness, nor does it result in wetland reconnection or enhancement of other floodplain ecosystem services. The suite of reconnection options we evaluate provides engineers, planners, and decision makers a framework from which they can further evaluate potential flood-risk reduction options. At least three of the eight reconnection scenarios (setting the western levee back, 1500-m, and 2000-m setbacks) along the Lower Tisza demonstrate that floodplain-wetland reconnection is possible while achieving the objectives of minimizing impacts on human populations and reducing flood heights.

Meander cores on the floodplain

The aim of the present study is to analyse the morphology, sedi-mentary structure and age of flood-free islands on the low-floodplain of the Lower Tisza in order to determine the date and causes of river incision. On the study area the identified 16 elevated surfaces were divided into two groups. The real or meander core floodplain islands appear in the northern and central units of the study area. They are characterized by steep slopes, elevated surface and small territory (2.1 km2 in average). The second type consists of elevated surfaces of point-bar systems and natural levees of paleo-channels, and they mostly appear in the southern unit. They have gentle slopes, smaller relative height and greater area (4.1 km2 in average). The spatial distribution of the two types refers to slow and slight tectonic uplift in the northern part of the study area, though in the south they refer only to the lack of sinking. The results of the sedimentological analysis on the meander core at Szegvár show that it originally belonged to the high-floodplain. Due to the slight tectonic uplift the meandering channel incised into the soft sediments, and as lateral erosion was possible, an ingrown-type meander developed, which later as a result of cut-off has become a meander core (or umlaufberg). Based on the OSL data the incision started at least 20.1±2.1 ka ago, and it terminated ca. 8-9 ka ago. The calculated bankfull discharge of the Szegvár paleo-meander is estimated to be 4000-7500 m3/s, referring to a considerably higher discharge than that of the present-day Tisza (800 m3/s). Similar planimetric meander parameters of paleo-channels on the high and low-floodplain suggest that the incision was not driven by climate, i.e. discharge change but primarily by tectonic movement. This is also supported by the height condition of the islands, as their surface is almost at the level of the high-floodplain.