Measurement of the spatial distribution of fluvial bedload transport velocity in both sand and gravel

2004 ◽  
Vol 29 (10) ◽  
pp. 1173-1193 ◽  
Author(s):  
Colin D. Rennie ◽  
Robert G. Millar
Keyword(s):  
Spatial Distribution ◽  
Bedload Transport ◽  
Transport Velocity ◽  
Sand And Gravel

Bed configuration and microscale processes in alluvial channels

1993 ◽  
Vol 17 (2) ◽  
pp. 123-136 ◽  
Author(s):  
André Robert
Keyword(s):  
Probabilistic Approach ◽  
Field Measurements ◽  
Bedload Transport ◽  
Transport Processes ◽  
Coarse Grained ◽  
Small Scale ◽  
Alluvial Channels ◽  
Gravel Beds ◽  
Sand And Gravel ◽  
Bed Material

Numerous recent studies on fluvial processes, both in Canada and internationally, have focused on small-scale phenomena. Investigations on the characterization of surface roughness in coarse-grained channels and its links with flow resistance and sediment transport processes have been a dominant field of research. Closely related is a second major area of investigation on turbulent flow structures in boundary layers over both sand and gravel beds and their relations with the transport of bed material. Phenomena potentially related to 'bursting' have been shown to control bedload transport processes and the concentration of sediment in suspension. Detailed investigations have also been conducted on the links between flow turbulence, bed material movement, and bed morphology at channel junctions. Finally, selective entrainment and transport of individual coarse particles have been studied from field measurements and laboratory experi ments. Emphasis has been put on bed microtopography, surface structure and texture, and on a probabilistic approach to bedload transport.

scholarly journals Wave-induced bedload transport – a study of the southern Baltic coastal zone

Geologos ◽  
2017 ◽  
Vol 23 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Aleksandra Dudkowska ◽  
Gabriela Gic-Grusza
Keyword(s):  
Shear Stress ◽  
Spatial Distribution ◽  
Coastal Zone ◽  
Wind Wave ◽  
Bedload Transport ◽  
Bottom Shear Stress ◽  
Wide Range ◽  
Alternative Approaches ◽  
Southern Baltic ◽  
Wave Induced

Abstract The wave-induced bedload transport and spatial distribution of its magnitude in the southern Baltic coastal zone of Poland are estimated. The vicinity of Lubiatowo was selected as a representative part of the Polish coast. It was assumed that transport is a function of shear stress; alternative approaches, based on force balances and discharge relationships, were not considered in the present study. Four models were studied and compared over a wide range of bottom shear stress and wind-wave conditions. The set of models comprises classic theories that assume a simplified influence of turbulence on sediment transport (e.g., advocated by authors such as Du Boys, Meyer-Peter and Müller, Ribberink, Engelund and Hansen). It is shown that these models allow to estimate transport comparable to measured values under similar environmental conditions. A united general model for bedload transport is proposed, and a set of maps of wave bedload transport for various wind conditions in the study area is presented.

scholarly journals Spatial distribution of aquifers in Bhairahawa-Lumbini area, Rupandehi district, west Nepal

2004 ◽  
Vol 30 ◽  
Author(s):  
Narendra Khattri
Keyword(s):  
Spatial Distribution ◽  
Cross Sections ◽  
Development Project ◽  
The Other ◽  
The West ◽  
Irrigation Project ◽  
Subsurface Geology ◽  
Deep Aquifers ◽  
Groundwater Irrigation ◽  
Sand And Gravel

The Bhairahawa-Lumbini Groundwater Irrigation Project (BLGWIP) is the largest groundwater development project of Nepal. It is situated in the middle of the Rupandehi district in west Nepal. The project covers an area of about 525 sq. km and serves over 20,000 ha of land by providing year-round irrigation. Over 180 deep tubewells were constructed by the BLGWIP within the area stretching between the Rohini Rive r in the east and the Kothi River in the west with the depth ranging from 80 to over 200 m. Seven different sections were taken to study the subsurface geology and nature of aquifer in this area. These seven sections include 61 deep tubewells. The lithological cross-sections show the distribution of pervious and impervious layers. The study shows that the aquifer materials are controlled by two major rivers: the Tinau River and Dano River. The lithological cross-sections I- I' and VII- VII' are taken from extreme west and east of the study area, respectively. Clay and silt horizons arc predominant in both sections. On the other hand, the remaining cross-sections II- II', III-III', I V- IV', V- V', and VI- VI' are taken from the central part of the study area. The litholog of boreholes of these sections show a significant amount of sand and gravel. Most of the deep aquifers recharge from infiltration of rainfall in the Bhabar Zone and also from the induced infiltration through the Tinau, Dano, Rohini, and other rivers flowing through the district. The study shows that the input to groundwater is as high as 464 million cubic metres (MCM). Out of this, 201 MCM goes into the shallow aquifers and 267 MCM flows into the deep aquifers.

scholarly journals Calculation of bedload transport in Swiss mountain rivers using the model sedFlow: proof of concept

2015 ◽  
Vol 3 (1) ◽  
pp. 35-54 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
M. Böckli ◽  
A. Badoux ◽  
J. M. Turowski ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Goodness Of Fit ◽  
Bedload Transport ◽  
Transport Processes ◽  
Estimation Methods ◽  
Mountain Streams ◽  
Proof Of Concept ◽  
Mountain Rivers ◽  
Total Transport ◽  
Simulation Results

Abstract. Fully validated numerical models specifically designed for simulating bedload transport dynamics in mountain streams are rare. In this study, the recently developed modelling tool sedFlow has been applied to simulate bedload transport in the Swiss mountain rivers Kleine Emme and Brenno. It is shown that sedFlow can be used to successfully reproduce observations from historic bedload transport events with plausible parameter set-ups, meaning that calibration parameters are only varied within ranges of uncertainty that have been pre-determined either by previous research or by field observations in the simulated study reaches. In the Brenno river, the spatial distribution of total transport volumes has been reproduced with a Nash–Sutcliffe goodness of fit of 0.733; this relatively low value is partially due to anthropogenic extraction of sediment that was not considered. In the Kleine Emme river, the spatial distribution of total transport volumes has been reproduced with a goodness of fit of 0.949. The simulation results shed light on the difficulties that arise with traditional flow-resistance estimation methods when macro-roughness is present. In addition, our results demonstrate that greatly simplified hydraulic routing schemes, such as kinematic wave or uniform discharge approaches, are probably sufficient for a good representation of bedload transport processes in reach-scale simulations of steep mountain streams. The influence of different parameters on simulation results is semi-quantitatively evaluated in a simple sensitivity study. This proof-of-concept study demonstrates the usefulness of sedFlow for a range of practical applications in alpine mountain streams.

Bedload Transport Velocity: Finding the Signal Amidst the Noise

2002 ◽  
Author(s):  
Colin D. Rennie ◽  
Robert G. Millar
Keyword(s):  
Bedload Transport ◽  
Transport Velocity

The influence of gravel mixed with sand on the formation and development of ripples.

2020 ◽  
Author(s):  
Katrien Van Landeghem ◽  
Irinios Yiannoukos ◽  
Connor McCarron ◽  
Jacob Morgan ◽  
Barney Clayton-Smith
Keyword(s):  
Sediment Transport ◽  
Critical Shear Stress ◽  
Bedload Transport ◽  
Migration Rates ◽  
Ripple Formation ◽  
Shelf Seas ◽  
Flow Speeds ◽  
And Migration ◽  
Sand And Gravel ◽  
Sediment Mixtures

<p>Coarse and bimodal sediment mixtures like sand and gravel are common in palaeo-glaciated shelf seas and in coastal environments. Their presence leads to more complex sediment transport and morphodynamic processes, depending on the ratio of sand to gravel in the bed. With increased pressure on our near-and offshore sea beds, there is a growing need to more accurately model sediment transport and bedform dynamics with an increasing focus on bimodal sand-gravel sediment mixtures. Revisiting the quantification of the hiding-exposure (HE) effect highlighted how differently sized grains in a bimodal mixture modify each other’s threshold of motion. The critical shear stress needed to mobilise the sand and gravel fractions increased by up to 75% and decreased by up to 64% respectively, compared to that needed to mobilise well-sorted sediment of similar size. Implementation of this newly quantified HE correction in current-and wave-driven models illustrated that its influence on bedload transport rates and bed morphodynamics was greatest for mixtures where gravel percentage ranges between 10 and 20 %. Laboratory experiments were therefore conducted to investigate ripple formation and bed dynamics in mixtures with gravel percentage between 0 and 25%. The development of initial bedforms was quicker in sand-gravel mixtures compared to those developed in pure sand, whilst final heights and migration rates of the developed ripples decreased with increasing fraction of gravel in the bed. During this presentation, a full comparison will be made of the morphology and “down-core” sedimentary properties of ripples formed at different flow speeds. If we want to use our seabeds cost-effectively and sustainably, we need a better understanding on the influence of a decreased mobilisation of the finer fractions and an increased mobilisation of the coarser fraction on the dynamics of beds with a bimodal sediment composition.</p>

scholarly journals Geophysical, geological, and hydrogeological characterization of a tributary buried bedrock valley in southern Ontario

2018 ◽  
Vol 55 (7) ◽  
pp. 641-658 ◽  
Author(s):  
Colby M. Steelman ◽  
Emmanuelle Arnaud ◽  
Peeter Pehme ◽  
Beth L. Parker
Keyword(s):  
Electrical Resistivity ◽  
Spatial Distribution ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Bedrock Channel ◽  
Quaternary Stratigraphy ◽  
Geophysical Logs ◽  
Sand And Gravel ◽  
Bedrock Aquifer ◽  
River Valleys

Buried bedrock valleys infilled with Quaternary-aged sediment have the potential to become productive aquifers owing to prevalent sand and gravel deposits often associated with these topographic lows. In areas where groundwater is drawn from the underlying bedrock aquifer, buried bedrock channels may significantly affect the spatial distribution of recharge and localized contaminant pathways. Therefore, understanding the form, distribution, and the nature of Quaternary infill sediments within these buried bedrock river valleys, and their relationship to hydraulically transmissive bedrock features is an important aspect of groundwater resource management. Here, we evaluate the effectiveness of electrical resistivity and seismic refraction collected over a partially urbanized 150 ha area with variable vegetation, roads, and structures, to map the spatial distribution of sediments and delineation of a channel segment associated with a regional bedrock valley. Electrical resistivity and seismic refraction was performed along 13 (covering ∼11.6 km) and seven transects (covering ∼0.9 km), respectively, to map and characterize the bedrock surface morphology beneath a variable thickness of unconsolidated deposits. Three continuously cored holes and downhole geophysical logs, supplemented with four nearby water well records captured the in-channel as well as adjacent Quaternary stratigraphy (∼15–40 m). Cores recorded multiple glacial till deposits and ice-marginal processes associated with ice advances and retreats. Hydraulic transmissivity of the bedrock around the valley feature was evaluated using a FLUTe hydraulic transmissivity profiling technique. This study demonstrates the potential of combining several surface geophysical methods with sedimentological analysis of continuous cores and hydraulic data for characterizing tributary bedrock channel morphology and Quaternary infill at a scale relevant to localized studies of municipal production well recharge zones and contaminant transport and fate.

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