scholarly journals Bedload transport measurements with impact plate geophones in two Austrian mountain streams (Fischbach and Ruetz): system calibration, grain size estimation, and environmental signal pick-up

2017 ◽  
Vol 5 (4) ◽  
pp. 669-687 ◽  
Author(s):  
Dieter Rickenmann ◽  
Bruno Fritschi
Keyword(s):  
Grain Size ◽  
Power Law ◽  
Bedload Transport ◽  
Mountain Streams ◽  
European Alps ◽  
Size Estimation ◽  
Linear Calibration ◽  
Calibration Relation ◽  
Gravel Bed Streams ◽  
Vehicle Movement

Abstract. The Swiss plate geophone system is a bedload surrogate measuring technique that has been installed in more than 20 streams, primarily in the European Alps. Here we report about calibration measurements performed in two mountain streams in Austria. The Fischbach and Ruetz gravel-bed streams are characterized by important runoff and bedload transport during the snowmelt season. A total of 31 (Fischbach) and 21 (Ruetz) direct bedload samples were obtained during a 6-year period. Using the number of geophone impulses and total transported bedload mass for each measurement to derive a calibration function results in a strong linear relation for the Fischbach, whereas there is only a poor linear calibration relation for the Ruetz measurements. Instead, using geophone impulse rates and bedload transport rates indicates that two power law relations best represent the Fischbach data, depending on transport intensity; for lower transport intensities, the same power law relation is also in reasonable agreement with the Ruetz data. These results are compared with data and findings from other field sites and flume studies. We further show that the observed coarsening of the grain size distribution with increasing bedload flux can be qualitatively reproduced from the geophone signal, when using the impulse counts along with amplitude information. Finally, we discuss implausible geophone impulse counts that were recorded during periods with smaller discharges without any bedload transport, and that are likely caused by vehicle movement very near to the measuring sites.

scholarly journals Bedload transport measurements with Swiss impact plate geophones in two Austrian mountain streams (Fischbach and Ruetz): system calibration, grain size estimation, and environmental signal pick-up

2017 ◽  
Author(s):  
Dieter Rickenmann ◽  
Bruno Fritschi
Keyword(s):  
Grain Size ◽  
Power Law ◽  
Bedload Transport ◽  
Mountain Streams ◽  
European Alps ◽  
Size Estimation ◽  
Linear Calibration ◽  
Calibration Relation ◽  
Gravel Bed Streams ◽  
Vehicle Movement

Abstract. The Swiss plate geophone system is a bedload surrogate measuring technique that has been installed in more than 20 streams, primarily in the European Alps. Here we report about calibration measurements performed in two mountain streams in Austria. The Fischbach and Ruetz gravel–bed streams are characterized by important runoff and bedload transport during the snowmelt season. A total of 31 (Fischbach) and 21 (Ruetz) direct bedload samples were obtained during a six year period. Using the number of geophone impulses and total transported bedload mass for each measurement to derive a calibration function, results in a strong linear relation for the Fischbach, whereas there is only a poor linear calibration relation for the Ruetz measurements. Instead, using geophone impulse rates and bedload transport rates indicates that two power law relations best represent the Fischbach data, depending on transport intensity; for lower transport intensities, the same power law relation is also in reasonable agreement with the Ruetz data. These results are compared with data and findings from other field sites and flume studies. We further show that the observed coarsening of the grain size distribution with increasing bedload flux can be qualitatively reproduced from the geophone signal, when using the impulse counts along with amplitude information. Finally, we discuss implausible geophone impulse counts that were recorded during periods with smaller discharges without any bedload transport, and that are likely caused by vehicle movement very near to the measuring sites.

scholarly journals sedFlow – an efficient tool for simulating bedload transport, bed roughness, and longitudinal profile evolution in mountain streams

2014 ◽  
Vol 2 (2) ◽  
pp. 733-772 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
J. M. Turowski ◽  
J. W. Kirchner
Keyword(s):  
Grain Size ◽  
Size Fraction ◽  
Bedload Transport ◽  
Mountain Streams ◽  
Size Distributions ◽  
Roughness Effects ◽  
Efficient Tool ◽  
Transport Dynamics ◽  
Grain Size Distributions ◽  
Bed Roughness

Abstract. Especially in mountainuous environments, the prediction of sediment dynamics is important for managing natural hazards, assessing in-stream habitats, and understanding geomorphic evolution. We present the new modelling tool sedFlow for simulating fractional bedload transport dynamics in mountain streams. The model can deal with the effects of adverse slopes and uses state of the art approaches for quantifying macro-roughness effects in steep channels. Local grain size distributions are dynamically adjusted according to the transport dynamics of each grain size fraction. The tool sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (www.wsl.ch/sedFlow). Examples of the application of sedFlow are given in a companion article by Heimann et al. (2014).

scholarly journals sedFlow – a tool for simulating fractional bedload transport and longitudinal profile evolution in mountain streams

2015 ◽  
Vol 3 (1) ◽  
pp. 15-34 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
J. M. Turowski ◽  
J. W. Kirchner
Keyword(s):  
Grain Size ◽  
Size Fraction ◽  
Bedload Transport ◽  
Mountain Streams ◽  
Stream Channels ◽  
Roughness Effects ◽  
Current Application ◽  
Transport Dynamics ◽  
Climate Change Effects ◽  
Simulation Speed

Abstract. Especially in mountainous environments, the prediction of sediment dynamics is important for managing natural hazards, assessing in-stream habitats and understanding geomorphic evolution. We present the new modelling tool {sedFlow} for simulating fractional bedload transport dynamics in mountain streams. sedFlow is a one-dimensional model that aims to realistically reproduce the total transport volumes and overall morphodynamic changes resulting from sediment transport events such as major floods. The model is intended for temporal scales from the individual event (several hours to few days) up to longer-term evolution of stream channels (several years). The envisaged spatial scale covers complete catchments at a spatial discretisation of several tens of metres to a few hundreds of metres. sedFlow can deal with the effects of streambeds that slope uphill in a downstream direction and uses recently proposed and tested approaches for quantifying macro-roughness effects in steep channels. sedFlow offers different options for bedload transport equations, flow-resistance relationships and other elements which can be selected to fit the current application in a particular catchment. Local grain-size distributions are dynamically adjusted according to the transport dynamics of each grain-size fraction. sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The high simulation speed allows for simulations of several years, which can be used, e.g., to assess the long-term impact of river engineering works or climate change effects. In combination with the straightforward pre- and postprocessing, the fast calculations facilitate efficient workflows for the simulation of individual flood events, because the modeller gets the immediate results as direct feedback to the selected parameter inputs. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (GPL) (www.wsl.ch/sedFlow). Examples of the application of sedFlow are given in a companion article by Heimann et al. (2015).

scholarly journals The transport of sediment mixtures examined with a birth-death model for grain-size fractions

2021 ◽  
Author(s):  
Shawn M. Chartrand ◽  
David Jon Furbish
Keyword(s):  
Time Series ◽  
Grain Size ◽  
Power Density ◽  
Bedload Transport ◽  
Mountain Streams ◽  
Particle Sizes ◽  
Experimental Conditions ◽  
Sediment Mixtures ◽  
Light Table ◽  
Birth Death

Abstract. Bedload transport of sediment mixtures in mountain streams is challenging to predict, with implications for understanding how rivers form and respond to environmental change. Experimental work shows that collective particle entrainment is an important contributing mechanism of bedload transport, but questions remain. We use four different time series of experimental sediment flux for granular particles 4–32 mm in diameter to indirectly examine the role of collective mobilization. Flux was measured at a fixed position in space using an imaging light table. The light table provides a flux measurement that is sampled at a resolution of 1 Hz, and for total time durations ranging from 75 to 240 min. Experimental conditions include periods of statistical steady-state, and transient adjustments due to changes of the upstream supply of water and sediment. We find that despite the contrasting experimental conditions, the time series encode a consistent transport behaviour within the Fourier domain: the transport of finer grain size populations has increasing power density for decreasing frequency, whereas the transport of larger grain size populations has a near constant power density across all frequencies. Hence, smaller particle sizes dominate the power spectra. We seek an explanation for this result, and elaborate on a probabilistic birth-death model introduced to the field by Christophe Ancey and colleagues. Analysis using the expanded birth-death model provides two important results. The transport of smaller particles includes collective entrainment terms that represent grain mobilization due to smaller and larger particle sizes colliding with the streambed surface. In contrast, the transport of larger particles includes collective entrainment terms limited to larger particle sizes. The size-dependent collective controls on particle mobilization is an important finding, and we show that it offers a testable explanation for observed flux differences between smaller and larger particle sizes, common to gravel-bed mountain streams. As a result, our work motivates the need to better understand collective entrainment within the context of granular sediment transport along mountain stream beds.

Bedload grain size estimation from the indirect monitoring of bedload transport with Swiss plate geophones at the Erlenbach stream

2014 ◽  
pp. 1907-1912 ◽  
Author(s):  
C Wyss ◽  
D Rickenmann ◽  
B Fritschi ◽  
J Turowski ◽  
V Weitbrecht ◽  
...  
Keyword(s):  
Grain Size ◽  
Bedload Transport ◽  
Size Estimation ◽  
Grain Size Estimation

Formation timescale model for a small sized Martian fluvial valley

2021 ◽  
Author(s):  
Vilmos Steinmann ◽  
Ákos Kereszturi
Keyword(s):  
Grain Size ◽  
Visual Analysis ◽  
Early Period ◽  
Atmospheric Modeling ◽  
Bedload Transport ◽  
Size Estimation ◽  
Geophysical Research ◽  
Sediment Grain Size ◽  
Size Frequency Distribution ◽  
Grain Size Estimation

<p>Most of the Martian fluvial valleys formed in the early period (around the Noachian-Hesperian boundary or before), but the formation durations are not well determined, however it would be important to understand as it is related to the climatic history and the reason for specific morphology of the Red Planet’s valleys. We estimated the formation duration for a hundred different sections of a small (~81 km long) Martian valley (called Tinto B, which is East of Palos crater and Tinro Vallis), using ArcMap and Excel software. We used the HRSC DTM (Digital Terrain Model), which was resampled from the resolution of 50 m/px to 100 m/px, because the used THEMIS TI dataset (used for grain size estimation) has a 100 m/px resolution. The visual morphological analysis we used the CTX images.  For the calculation we considered the cross-sectional profile of the valley as a trapezoid shape and calculated the hydraulic radius for it and used several hydraulic variables, like average flow velocity, bedload transport rate, sediment and flow discharge [1], slope of energy grade line. For the formation timescale calculation the Meyer-Peter and Muller bedload transport equation [2] was used. For the sediment grain size estimation we used the THEMIS TI dataset and calculated the shear stress and the Shield parameter from it [3]. The bed of the valley is covered with aeolic sand, which does not represent the grain size of the eroded bedrock, which probably took part in the original formation process. For this reason we sampled the grain size from exposures on both sides of the valley walls, where the original bedrock represented to the best approximation and continuously. The main aim of the work is to compare the different sections of the analysed valley by the final assumed age and different variables and morphology. The detailed morphology analísation comes from the previously made erosion-accumulation results [4] and the visual analysis of the valley. From the given section results the median formation time scale of the valley can be calculated also. With this method the Martian valleys can be comparable with the terrestrial mars-analog valleys after the same calculations. The estimated formation timescale of the whole valley will be compared with the result of the crater size frequency distribution based statistically estimated age of the valley bed. </p> <p> </p> <p>References:</p> <p>[1] - M. R.T. Hoke, B. M. Hynek, G. E. Tucker, Formation timescales of large Martian valley networks, Earth and Planetary Science Letters, 2011, Volume 312, Issues 1–2</p> <p>[2] - M. Wong, G. Parker, Reanalysis and correction of bed-load relation of Meyer-Peter and Muller using their own database, J. Hyrdaul. Eng, 2006, pp. 1159-1168</p> <p>[3] - L. K. Fenton, J. L. Bandfield, A. W. Ward, Aeolian process on Mars: atmospheric modeling and GIS analysis, Journal of Geophysical Research, 2003</p> <p>[4] - V. Steinmann, Á. Kereszturi, L. Mari, Geomorphological analysis of Tinto-B Vallis on Mars, Hungarian Geographical Bulletin, 2020, pp 333-348</p>

Controlled experiments and finite element simulations with the Swiss plate geophone bedload monitoring system: particle size identification and transport mode

2021 ◽  
Author(s):  
Zheng Chen ◽  
Siming He ◽  
Tobias Nicollier ◽  
Lorenz Ammann ◽  
Alexandre Badoux ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Finite Element ◽  
Quantitative Agreement ◽  
Bedload Transport ◽  
Material Structure ◽  
Flume Experiments ◽  
Fem Simulations ◽  
Transport Mode ◽  
Signal Response

<p>The Swiss plate geophone (SPG) system is an indirect bedload transport monitoring device that records the acoustic signals generated by bedload particle impacts, with the goal to derive the bedload flux and grain size distribution. Particle drop experiments with quartz spheres in quiescent water in a flume setting were performed to investigate the dynamic signal response of the SPG system impacted by particle-like objects varying in size and impact location. Systematic flume experiments with natural bedload particles in flowing water were conducted to study the effects of impact angle and transport mode (saltating, rolling and sliding) on the SPG signals. For each impact caused by a single particle, the number of signal impulses, the amplitude, the positive area surrounded by the signal envelope, and the centroid frequency were extracted from the raw geophone monitoring data. The finite element method (FEM) was used to construct a virtual model of the SPG system and to determine the propagation characteristics of the numerical stress wave in the material structure. The experimental and numerical results showed a qualitative and partially quantitative agreement in the changes of the signal impulses, the amplitude, and the envelope area with increasing colliding sphere size. The centroid frequencies of the SPG vibrations showed qualitatively similar dependencies with increasing particle size as some field measurements for the coarser part of the investigated range of impact sizes. The effects of variable particle impact velocities and impact locations on the geophone plate were also investigated by drop experiments and compared to FEM simulations. In addition, the signal response for different bedload transport modes and varying impact angles were explored. In summary, the FEM simulations contribute to the understanding of the signal response of the SPG system and the findings in this study may eventually result in improving the bedload grain size classification and transport mode recognition.</p>

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