scholarly journals Morphological Investigation of a Critical Reach of the Upper Hungarian Danube

2017 ◽  
Author(s):  
Gergely T. Török ◽  
Sándor Baranya
Keyword(s):  
Human Impacts ◽  
Morphological Changes ◽  
Acoustic Doppler Current Profiler ◽  
River Regulation ◽  
Danube River ◽  
Hydropower Plant ◽  
Essential Information ◽  
Inland Navigation ◽  
Current Profiler ◽  
The Stability

The aim of this study is to analyze the current morphological changes and to predict the potential future trends of a critical reach of the upper Hungarian Danube River. In this section of the river the morphological features have undergone significant changes, mainly due to human impacts, such as the construction of the Gabcikovo hydropower plant close to the Slovakian border, or the river regulation measures with groin fields along the Hungarian reach. The morphological changes of the river inherently led to river management issues, e.g. the developed gravel bars caused problems for inland navigation. In order to reveal and understand the characteristic morphodynamic processes, results from past bed geometry surveys were assessed, moreover, extensive field measurement campaigns were carried out, including bathymetry survey, flow survey with fixed and moving Acoustic Doppler Current Profiler (ADCP), bed material sampling and bedload measurements. The utilization of up-to-date field data processing methods provided essential information on the current dominant morphological processes and finally, suggestions were made on the stability of the river planform.

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

2019 ◽  
Vol 50 (2) ◽  
pp. 417-430 ◽  
Author(s):  
Tímea Kiss ◽  
Károly Fiala ◽  
György Sipos ◽  
Gábor Szatmári
Keyword(s):  
Human Impacts ◽  
Morphological Changes ◽  
River Regulation ◽  
Mass Movements ◽  
Channel Adjustment ◽  
Flood Level ◽  
Flow Changes ◽  
Tisza River ◽  
Natural Channel

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.

scholarly journals A Study of the Location of the Entrance of a Fishway in a Regulated River with CFD and ADCP

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Anders G. Andersson ◽  
Dan-Erik Lindberg ◽  
Elianne M. Lindmark ◽  
Kjell Leonardsson ◽  
Patrik Andreasson ◽  
...  
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Field Measurements ◽  
Fish Passage ◽  
Hydropower Plant ◽  
Regulated River ◽  
Unstable Flow ◽  
River Bed ◽  
Current Profiler ◽  
Tailrace Tunnel ◽  
Made In

Simulation-driven design with computational fluid dynamics has been used to evaluate the flow downstream of a hydropower plant with regards to upstream migrating fish. Field measurements with an Acoustic Doppler Current Profiler were performed, and the measurements were used to validate the simulations. The measurements indicate a more unstable flow than the simulations, and the tailrace jet from the turbines is stronger in the simulations. A fishway entrance was included in the simulations, and the subsequent attraction water was evaluated for two positions and two angles of the entrance at different turbine discharges. Results show that both positions are viable and that a position where the flow from the fishway does not have to compete with the flow from the power plant will generate superior attraction water. Simulations were also performed for further downstream where the flow from the turbines meets the old river bed which is the current fish passage for upstream migrating fish. A modification of the old river bed was made in the model as one scenario to generate better attraction water. This considerably increases the attraction water although it cannot compete with the flow from the tailrace tunnel.

scholarly journals Hydrological and Morphological Changes of the Lower Danube Near Mohács, Hungary

2016 ◽  
Vol 9 (1-2) ◽  
pp. 1-6
Author(s):  
Judit Nagy ◽  
Tímea Kiss
Keyword(s):  
Cross Section ◽  
Water Regime ◽  
Human Impacts ◽  
Morphological Changes ◽  
Cooling Water ◽  
Danube River ◽  
Regime Changes ◽  
Shipping Water ◽  
High Record ◽  
Channel Development

Abstract Various direct human impacts changed the hydro-morphology of the Danube during the last centuries. The aims of the present study are (1) to analyze the water regime of the Danube River using the data of Mohács gauging station (1900-2013), and (2) to study the channel development (1952-2014) in connection with water regime changes and human impacts at a section near Bogyiszló (upstream of Mohács). According to the results the height of low water stages decreased by approx. 136 cm (1.2 cm/year), and new, high record flood stages were measured too. The discharge values appertaining to the same low water stages doubled, thus nowadays almost twice as much water flows through the cross-section of the channel at a given stage as at the beginning of the studied period. As the duration of low stages increased, the sandbar development intensified, thus the channel became narrower (by 48% at some places) and deeper thalweg evolved. Therefore, a smaller cross-section for flood-waves evolved, affecting the height of flood. These changes affect shipping, as due to riverbed incision and decrease of low water stages, the lowest shipping water level has to be set repeatedly at lower stages. Besides water extraction from the channel will have difficulties, thus irrigation and industrial cooling water supply will be limited in the future.

scholarly journals Hydroacoustic and Pressure Turbulence Analysis for the Assessment of Fish Presence and Behavior Upstream of a Vertical Trash Rack at a Run-of-River Hydropower Plant

2018 ◽  
Vol 8 (10) ◽  
pp. 1723 ◽  
Author(s):  
Marc Schmidt ◽  
Jeffrey Tuhtan ◽  
Martin Schletterer
Keyword(s):  
Spatial Distribution ◽  
Flow Characteristics ◽  
Acoustic Doppler Current Profiler ◽  
Hydropower Plant ◽  
Hydro Power ◽  
Starting Point ◽  
Current Profiler ◽  
Spatial Estimates ◽  
Flow Turbulence ◽  
Turbulence Analysis

The spatial distribution of fish upstream of a vertical trash rack was investigated at the hydropower plant Kirchbichl in the alpine River Inn (Tyrol, Austria). The objective of the research project “FIDET” was to establish a non-invasive methodology to study fish presence and flow characteristics at large hydro power sites. A new monitoring approach was developed combining hydroacoustic observations of fish locations with multivariate hydrodynamic data. This was accomplished by utilizing complementary observations from multiple underwater sensor technologies: First, an array of echosounders were deployed at a fixed cross-section upstream of the trash rack for long-term monitoring. Afterwards, detailed underwater surveys with “acoustic cameras” (DIDSON and ARIS) revealed that the spatial distributions of fish in front of the trash rack were highly heterogeneous. The spatial distribution of the flow field was assessed via the time-averaged velocity fields from acoustic Doppler current profiler (ADCP). Finally, a custom pressure-based flow turbulence probe was developed, providing spatial estimates of flow turbulence immediately upstream of the trash rack. The significant contribution of this work is to provide a multi-modal monitoring approach incorporating both fish position data and hydrodynamic information. This forms the starting point for a future objective, namely to create an automated, sonar-based detection and control systems to assist and monitor fish protection operations in near real-time.

scholarly journals THE STRUCTURE OF THE VELOCITY FIELD OF THE LOMONOSOV EQUATORIAL CURRENT BASED ON THE MEASUREMENTS IN SPRING 2014 AND AUTUMN 2015

2019 ◽  
Vol 47 (2) ◽  
pp. 108-138
Author(s):  
T.A. Demidova ◽  
V.G. Neiman ◽  
E.G. Morozov
Keyword(s):  
Velocity Field ◽  
Acoustic Doppler Current Profiler ◽  
Small Scale ◽  
Published Data ◽  
The Core ◽  
Current Profiler ◽  
Equatorial Current ◽  
Dimensional Section ◽  
Ocean Environment ◽  
The Stability

Two examples of measurements of oceanic equatorial currents in the Atlantic using an shipborne acoustic Doppler current profiler SADCP on meridional sections across the equator in spring 2014 at 23°W and autumn 2015 at 34°W are considered. The relevant data of some previous observations in this region are also used for comparison. The methods for studying the Lomonosov Current using ship profiling and moorings are discussed. According to the results of profiling with a two-minute averaging of the source data of the section of September 27, 2015, a structure of the two-dimensional section of the high-resolution velocity field is presented, which is characterized by small-scale fragmentary stratification, which was previously detected only from one-dimensional data of vertical soundings of velocity and other parameters of the ocean environment. Using the example of comparing this detailed section with the versions for other time averages (15 and 60 min) differences in the estimates of parameters of the velocity field due to the averaging are specified. Using the example of vertical profiles through the core of the Lomonosov Undercurrent (EUC) in the springs of 2002 and 2014 and winters of 2002 and 1971 at the locations close to 23°W, the stability of the annual cycle of fluctuations of the intensity of currents in the core and the position of the core in a multiyear aspect is illustrated. The agreement of our results with other previously published data is shown. The main parameters of the velocity field over the equatorial section on April 17, 2014 indicate a high probability of the outcropping of the easterly flow on the surface. Similar episodes of outcropping in 2002 within the PIRATA program together with corresponding intervals of changing the direction of the zonal component of wind speed derived from the Era Interim reanalysis from westward to eastward are demonstrated. A similar correlation with the wind is assumed to occur on April 17, 2014.

Klamath River Water Quality and Acoustic Doppler Current Profiler Data from Link River Dam to Keno Dam, 2007

2008 ◽  
Author(s):  
Annett B. Sullivan ◽  
Michael L. Deas ◽  
Jessica Asbill ◽  
Julie D. Kirshtein ◽  
Kenna D. Butler ◽  
...  
Keyword(s):  
Water Quality ◽  
River Water ◽  
Acoustic Doppler Current Profiler ◽  
River Water Quality ◽  
Klamath River ◽  
Current Profiler ◽  
Profiler Data
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