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August 2009 - present
Publications
Publications (97)
A three-dimensional numerical model that computes hydrodynamics and morphodynamics is applied to the problem of calculating local scour around cylinders. A nested grid approach is implemented in the numerical scheme in order to decrease the overall computational demand but at the same time allow for high spatial resolution around the cylinder to in...
An estimation procedure for suspended sediment concentrations based on the intensity of backscattered sound of acoustic Doppler current profilers (ADCP) is introduced in this paper. Based on detailed moving and fixed boat ADCP measurements with concurrent sediment sampling, we have successfully calibrated the estimation method for a reach of River...
The paper introduces a three-dimensional numerical model that solves the Reynolds Averaged Navier-Stokes (RANS) equations on a curvilinear grid system using a novel nested grid approach. The main benefit of the model is the possibility to model locally complex hydraulic features in large rivers like the flow field at hydraulic structures. The entir...
A comprehensive flow analysis for a confluence of two medium-sized (Qmean ≈ 30–50 m3/s) Hungarian rivers was carried out by means of a three-dimensional Reynolds-averaged Navier–Stokes modelling. The model was validated against detailed fixed and moving Acoustic Doppler Current Profiler velocity profiling. Unsteady simulations with steady-state bou...
Spatial complexity of turbulent flow conditions has been investigated by means of ADCP measure-ments and CFD modelling in river Danube. The study area was a meandering river reach, characterized by shallows and strongly influenced by various river training works. High resolution bed survey and freezing plate sampling provided input river bed data f...
A three‐dimensional coupled hydrodynamic and sediment transport model was employed to simulate the suspended sediment transport at a section of the Danube River, in Hungary. The case study is characterised by a highly complex hydromorphological system due to the nearby tributary inflow, the high number of river regulation structures as well as the...
River temperature is a critical parameter influencing aquatic ecosystems and water quality. However, it can be changed by natural (e.g., flow and depth conditions) and human factors (e.g., waste and industrial water drainage). Satellite-based monitoring offers a valuable tool for assessing river temperature on a large scale, elucidating the impacts...
Since the ingestion of both natural and anthropogenic microfibers produces a deleterious effect on aquatic organisms, it is crucial to explore the emission of these pollutants by WWTPs into the receiving water bodies, such as rivers. Cellulose- and petroleum-based microfibers, as well as microplastic particles, were collected from the effluent of a...
Understanding of the contribution of abiotic drivers to fish community structure in very large rivers is poor. In this study, we assigned the occurrence data of the 20 most common fish species in the Hungarian section of the Danube River from 2004 to 2022 to hydrodynamic variables from hydrological datasets and hydrodynamical simulations and looked...
Considering currently operative European and worldwide regulations, preserving and/or improving the state of remnant alluvial floodplains is a high-priority goal for experts. One of the threats is the decrease of lateral connectivity: due to the erosion in the mainstem riverbed and the sedimentation of the floodplain and its channels, the bed eleva...
Plastic waste has become a major global issue, with over 390.7 million tons of plastic produced in 2021. Because of its durability, low recycling rates, poor waste management, and maritime use, a considerable portion of plastic waste ends up in aquatic environments. Photo-oxidation and other mechanisms degrade plastics into microplastics (MPs), whi...
A tanulmányban egy 3D numerikus modellt építettünk fel, igazoltunk és alkalmaztunk a Duna felső-magyarországi szakaszának lebegtetett hordalékszállításának szimulálására. A mintaterület igen összetett, mivel folyószabályozási művek, illetve a Mosoni-Duna felől a Rábán levonuló nagyvíz esetén érkező hordalékcsóva terjedése is befolyásolja a lebegtet...
Zusammenfassung
Buhnen werden im Wasserbau vielfach angewendet und sind aufgrund der komplexen Strömungsverhältnisse in Abhängigkeit von Wasserstand und Buhnengeometrie herausfordernd bezüglich der Wirksamkeit und der Eignung als flussbauliche Maßnahme. Physikalische Modellierungen werden seit etwa 130 Jahren im Wasserbau angewendet, bei Bedarf mit...
The sediment of alluvial riverbeds plays a significant role in river systems both in engineering and natural processes. However, the sediment composition can show high spatial and temporal heterogeneity, even on river-reach scale, making it difficult to representatively sample and assess. Conventional sampling methods are inadequate and time-consum...
The level set method-based, multiphase hydro-and morphodynamic numerical model REEF3D is used for the simulation of the flow conditions and local scouring around submerged bridge decks. Presence of hydraulic jumps, bridge overtopping, pressurized jets and the resulting scouring make the selected test cases especially challenging from the numerical...
Wastewater effluents are the main sources of microplastic particles (fibers, fragments, cosmetic products), as well as the natural and "man-made” cellulose-based fibers in the riverine environment. Numerous studies have been conducted to qualify and quantify these solid particles in the effluents and rivers. In the riverine environment both the sus...
A new measurement protocol, labeled Acoustic Mapping Velocimetry (AMV), has been successfully tested for in‐situ estimation of bedload transport features in sandy beds. The AMV has proven efficient in using the dune‐tracking method (DTM) for characterizing the bedform geometry and dynamics as well as for estimation of the rates of bedload transport...
Zusammenfassung
Die Donau und die sie umgebende Landschaft liegen heute im Bereich verschiedener Interessen wie Hochwasserschutz, Wasserkraft, Schifffahrt und Ökologie. Aufgrund dieser Tatsache ist das ehemals ungezähmte und wilde Flusssystem seit Ende des 19. Jahrhunderts mit einer Vielzahl anthropogener Veränderungen konfrontiert, die vielfältige...
An increasing discrepancy between surplus and lack of sediments can be observed in many river basins. This leads to an increase of flood risks and a reduction of navigation possibilities, hydropower production and negatively impacts ecology. Thus, a main task is to improve sediment management as well as river morphology. To close existing knowledge...
Zusammenfassung
Numerische Modelle stellen ein wichtiges Werkzeug zur Analyse und Bewertung von Gewässerprozessen sowie von flussbaulichen Maßnahmen dar. In den beiden Projekten DREAM SK-AT (Interreg V‑A Slowakei – Österreich) und SEDDON II (Interreg V‑A Österreich – Ungarn) wurden Nutzungsansprüche bezüglich Wasserkraft, Hochwasser, Schifffahrt, Ö...
A Duna-vízgyűjtő magyarországi részének felülvizsgált, 2015. évi vízgyűjtő-gazdálkodási terve („VGT2”) alapján legtöbb folyónkon medermélyülés figyelhető meg, amely magával vonja a vízszintek süllyedését. A legjelentősebb medermélyülés a Dráva folyón tapasztalható (kb. 3-4 cm/év), amit a természetes mederváltozási folyamatok mellett különféle inten...
The impacts of navigation on the hydromorphological and ecological conditions of rivers are manifold. Most of the relevant effects can be linked to ship-induced waves, which temporarily alter the prevailing flow conditions. The impacts of waves are usually the highest in the shallower (littoral) zones, where the whole water column is affected by th...
This paper describes the in-situ implementation of a recently developed bedload transport estimation method, called Acoustic Mapping Velocimetry (AMV). The method combines components and processing protocols from acoustic and image-based methods to provide velocity maps of bedforms migrating in the riverbed. The AMV implementation is illustrated wi...
The sediment of alluvial riverbeds plays a significant role in river systems both in engineering and natural processes. However, the sediment composition can show great spatial and temporal heterogeneity, even on river reach scale, making it difficult to representatively sample and assess. Indeed, conventional sampling methods in such cases cannot...
Direct or indirect effects of nuclear power plants’ (NPPs) warmwater effluents on the structure of biotic assemblages are poorly known in very large rivers. We examined changes in physical habitat structure, temperature condition and their possible effects on the structure of Danubian fish assemblages due to the outflow of the Paks NPP’s warmwater...
Ship-induced wave wash affects the hydromorphological and ecological state of rivers through various mechanisms. The direct proximity of the riverbank is usually the most exposed, as the hydrodynamic stresses are the highest in these shallow water areas. Contrary to the steady and almost still, natural flow conditions (i.e., no waves of anthropogen...
Fluvial sediment samples (river bottom sediment, suspended sediment and active floodplain/overbank) were collected in 2 baseline stations of the Transnational Monitoring Network for each of the 12 countries in the Danube Basin Region, according to a harmonized methodology. The sediment samples were analyzed for selected hazardous substances (HSs):...
Aquatic ecosystems are affected by anthropogenic influence in many aspects. One among those is thermal pollution, which may be caused by discharging used cooling water of nuclear power plants back to the recipient water body. Research targeting this effect tends to focus more on coastal areas and small rivers, while less is known about the impact o...
Establishing and operating a harmonized sediment monitoring system along large rivers such as the Danube River is a challenging international task. As an element of such a system, a new monitoring site with state-of-the-art instrumentation is currently under development in the Upper-Hungarian section of the Danube River. The monitoring station will...
Bedload transport is an important factor to describe the hydromorphological processes of fluvial systems. However, conven-
tional bedload sampling methods have large uncertainty, making it harder to understand this notoriously complex phenom-
enon. In this study, a novel, image-based approach, the Video-based Bedload Tracker (VBT), is implemented t...
The river flow and the sediment that composes the riverbed are in constant interaction. Despite its importance, this interaction still has undiscovered aspects and unanswered questions. In alluvial rivers, one important factor that describes their morphological changes is the bedload yield. Defining its value however, remains a complex task, where...
Three-dimensional computational fluid dynamics modeling is ever more frequently used to solver various flow related problems. In case of the hydraulic engineering community, tasks usually range from the prediction of complex free surface flow conditions up to various sediment transport related questions, such as local scouring. In highly turbulent...
Non-intrusive technologies for the in-situ measurement of river morphological features are increasingly popular in the scientific and practice communities due to their efficient and productive data acquisition. While the measurement of suspended load with optical and acoustic technologies is currently an active area of research, the measurement of...
This paper presents a proof of concept that acoustic velocity and backscatter intensity measurements can provide essential information on ship wave-induced sediment transport processes in the littoral zone of a large river. Through a case study in the Hungarian section of Danube River, a combined application of an acoustic Doppler velocimeter (ADV)...
Quantification of fish habitat relationships is a prerequisite in environmental management. Here, we compare the results of a 2D and a 3D hydrodynamic simulation in modeling fish habitat relationships in a very large river (Danube River, Hungary). We show that despite the great spatial variability of significant hydro-morphological variables (water...
The effects of inland navigation on the aquatic ecosystem are numerous. One of the most relevant impacts from the ecohydraulic point of view is ship-induced waves, resulting in the local and temporary alteration of the hydrodynamic regime, especially in shallow water areas. In this paper, a novel hydrodynamic modeling-based evaluation framework is...
SAŽETAK Ušće rijeke Drave u Dunav karakteriziraju specifični morfodinamički procesi znatne sedimentacije nanosa i posljedično problema vezanih uz osiguravanje gabarita plovnog puta. Analiza morfodinamičkih promjena zahtijeva dugoročno praćenje režima voda i nanosa kako bi se odredilo ravnotežno stanje u odnosu na referentne uvjete (nulto stanje utv...
Computational Fluid Dynamics (CFD) modeling has become a widely used research tool in the hydraulic engineering community, however, for many problems the numerical model setup and even the selection of the suitable hydrodynamic solver is still a challenging task. This is the case for fine scale analysis of flow features around hydraulic structures...
Drava River confluence is characterized by specific morphodynamic processes under which significant sediment deposition is occurring at the Drava River mouth, impeding fairway conditions. Morphodynamic analysis requires long-term hydraulic and sediment transport regime data as input for estimation of equilibrium conditions, taking into account base...
The composition or bed material plays a crucial role in the physical hydromorphological processes of fluvial systems. However, conventional bed material sampling methods provide only pointwise information, which can be inadequate when investigating large rivers of inhomogeneous bed material characteristics. In this study, novel, image-based approac...
The monitoring of fluvial suspended sediment transport plays an important role in the assessment of morphological processes, river habitats, or many social activities associated with river management. However, establishing and operating a well-functioning sediment monitoring system requires the involvement of advanced indirect methods. This study i...
In this study, the field measurement-based validation of a novel sediment transport calculation method is presented. River sections with complex bed topography and inhomogeneous bed material composition highlight the need for an improved sediment transport calculation method. The complexity of the morphodynamic features (spatially and temporally va...
Az ökohidraulika vagy élőhely-hidraulika az ökológia és a hidraulika határán elhelyezkedve, a vízi környezetbeli élő és élettelen, másszóval biotikus és abiotikus paraméterek között keres összefüggéseket. A tudományterület fő célja a hidromorfológiai változók és a vízi élőlények térbeli előfordulása és mennyiségi viszonyai közötti kapcsolatok minél...
The temporal alteration of the hydrodynamic regime in rivers due to navigation has significant effects on riverine ecosystems. Most of the key mechanisms and interactions between hydrodynamic and ecological variables have already been revealed; however, the quantitative evaluation of biotic and abiotic variables still stands a challenge. This paper...
This study proposes a spatiotemporally Adaptive Search Area (SA) size selecting algorithm for Particle image velocimetry (PIV), ASAPiv. The presented method releases the constraint of conventionally used static SAs, offering a significant computational performance increase through optimizing the dimensions of the SA according to the local flow cond...
Theanalysisofbed-loadmovementisessentialtounderstandmorphologicalprocessesinalluvialrivers.Betterunderstanding of these mechanisms may help predict changes occurring in the riverbed during flood events, estimate the effect of these events on riverbank ecosystems, and forecast the amount of sediment deposited in reservoirs. Mostly physical based samp...
The physical interaction of aquatic vegetation with flow and sediment has long been investigated as it affects ecological conditions around submerged macrophytes, determines the effectiveness of shore protection by vegetation, and governs the natural evolution of vegetation patches through enhanced sedimentation. Tower-based imaging techniques such...
![Figure 3. Shields-Parker diagram [7].](profile/Gergely-Torok/publication/330128132/figure/fig2/AS:711167869739022@1546567041687/Shields-Parker-diagram-7_Q320.jpg)
The aim of this study is to introduce a novel method which can separate sand- or gravel-dominated bed load transport in rivers with mixed-size bed material. When dealing with large rivers with complex hydrodynamics and morphodynamics, the bed load transport modes can indicate strong variation even locally, which requires a suitable approach to esti...
Many pharmaceuticals inevitably end up in surface waters, exerting unwanted biological activity in nontarget organisms. This effect is confined by the compound's environmental persistence. Regulatory laboratory simulation tests are used in persistence assessment and exposure modeling. While doubt has been expressed about the usefulness of laborator...
Three-dimensional numerical modelling with nested grid approach is tested in this paper to simulate hy-drodynamics and sediment transport in a large sand bed river with large bedforms.
This paper introduces a methodology to prepare digital maps of bed material composition in rivers with inhomogeneous bed material, which can be used in riverine habitat assessment studies. The method combines information from physical bed material samplings and results from three-dimensional computational flow modeling. The main idea is to set up a...
The aim of this study is to introduce a novel method which can separate sand or gravel dominated bed load transport in rivers with mixed-size bed material. In engineering practice, the Shields-Parker diagram could be used for such purposes, however, the method has certain applicability limits, due to the fact that it is based on uniform bed materia...
Riverine ship traffic results in the temporal alteration of the flow regime in the close proximity of the vessels, but waves propagating in the direction of banks may also have significant hydrodynamic effects. Ecohydraulic problems related to vessel induced wave wash (e.g. bank erosion; drift of larval fish or macroinvertebrates) are getting incre...
Hydromorphological features of rivers, such as flow depth, flow velocity, and the composition of bed material play a crucial role in the habitat selection of fish. Although these basic hydromorphological parameters can be determined with high spatial and temporal resolution using state‐of‐the‐art investigation methods, only few studies deal with th...
Vessel generated waves are investigated with video based methods in the littoral zone of a river. LSPIV is used for the assessment of wave runup dynamics, while basic photogrammetric methods are used for the temporal analysis of small frequency waves.
An experimental study was conducted to explore sediment particle motion in an open channel and its relationship to bedform characteristics. High-definition submersed video cameras were utilized to record images of particle motion over a dune’s length scale. Image processing was conducted to account for illumination heterogeneity due to bedform geom...
An experimental study was conducted to clarify sediment particle motion and its relation to the dune migration. High-definition action video cameras were utilized to record the images of particle motion in a domain covering dune scale. Image processing was conducted to homogenize the illumination heterogeneity due to bed form and light reflection a...
Accurate estimation of discharge capacity and local hydrodynamics are essential when designing hydraulic structures. Instead of the application of conventionally used empirical relationships, this study introduces a 3D numerical modeling technique which is capable to adequately predict both the discharge-upstream water level relationship and the fl...
The metadata of the Norwegian historical topographic maps are given, in order to make its georeference
possible, using just their corners points as control points. The earliest systematic topographic map product is
the square mile-maps (kvadratmil kart). They cover the southern leg of the Swedish border region of Norway
as it was in the end of 18 t...
The 1:50,000 and 1:100,000 scale historical sheets of the Norwegian topographic 'Rektangelkart' map series were georeferenced, in order to obtain the original hydrography of the Gaula River, at a ca 50 kilometer long section between Støren and the estuary to the Gulosen Bay. The 1:50,000 scale sheets are the earliest systematic topographic works of...
The poster presents the numerical modelling of the hydromorphological evolution of a 10-km reach of the Po River close to Ostiglia in Italy, affected by the presence of two bridges.
The paper presents the numerical modelling of the hydromorphological evolution of a 10-km reach of the Po River close to Ostiglia in Italy, affected by the presence of a railway bridge. The 3D simulation is performed using the freely available code SSIIM, developed at the University of Science and Technology in Trondheim in Norway. The domain consi...
The reliable prediction of morphological changes of rivers is of major need in the field of river engineering. Besides the conventionally used empirical procedures or hydraulic scale models, the numerical modeling is a progressively developing, but still not a widespreadly used tool. Moreover, the sediment transport modeling at non-uniform river be...
