scholarly journals Numerical simulation of hydrodynamic characteristics and bedload transport in cross sections of two gravel-bed rivers based on one-dimensional lateral distribution method

2020 ◽  
Vol 35 (2) ◽  
pp. 203-216
Author(s):  
Chien Pham Van ◽  
Vivien Chua
Keyword(s):  
Numerical Simulation ◽  
Cross Sections ◽  
Bedload Transport ◽  
Lateral Distribution ◽  
Hydrodynamic Characteristics ◽  
Distribution Method ◽  
One Dimensional ◽  
Gravel Bed ◽  
Gravel Bed Rivers

scholarly journals Geometry of meandering and braided gravel-bed threads from the Bayanbulak Grassland, Tianshan, P. R. China

2016 ◽  
Vol 4 (1) ◽  
pp. 273-283 ◽  
Author(s):  
François Métivier ◽  
Olivier Devauchelle ◽  
Hugo Chauvet ◽  
Eric Lajeunesse ◽  
Patrick Meunier ◽  
...  
Keyword(s):  
Grain Size ◽  
Scaling Laws ◽  
Sedimentary Basin ◽  
Bedload Transport ◽  
Braided River ◽  
Statistical Distributions ◽  
Meandering Rivers ◽  
Gravel Bed ◽  
Threshold Theory ◽  
Gravel Bed Rivers

Abstract. The Bayanbulak Grassland, Tianshan, P. R. China, is located in an intramontane sedimentary basin where meandering and braided gravel-bed rivers coexist under the same climatic and geological settings. We report and compare measurements of the discharge, width, depth, slope and grain size of individual threads from these braided and meandering rivers. Both types of threads share statistically indistinguishable regime relations. Their depths and slopes compare well with the threshold theory, but they are wider than predicted by this theory. These findings are reminiscent of previous observations from similar gravel-bed rivers. Using the scaling laws of the threshold theory, we detrend our data with respect to discharge to produce a homogeneous statistical ensemble of width, depth and slope measurements. The statistical distributions of these dimensionless quantities are similar for braided and meandering threads. This suggests that a braided river is a collection of intertwined threads, which individually resemble those of meandering rivers. Given the environmental conditions in Bayanbulak, we furthermore hypothesize that bedload transport causes the threads to be wider than predicted by the threshold theory.

Temporal variations in bedload transport rates and sediment storage in gravel-bed rivers

1992 ◽  
Vol 16 (3) ◽  
pp. 319-338 ◽  
Author(s):  
Trevor Hoey
Keyword(s):  
Three Dimensional ◽  
Temporal Variations ◽  
Sampling Interval ◽  
Bedload Transport ◽  
Sediment Storage ◽  
Data Set ◽  
Gravel Bed ◽  
Wide Range ◽  
Gravel Bed Rivers ◽  
Bed Waves

Temporal variability in bedload transport rates and spatial variability in sediment storage have been reported with increasing frequency in recent years. A spatial and temporal classification for these features is suggested based on the gravel bedform classification of Church and Jones (1982). The identified scales, meso-, macro-, and mega- are each broad, and within each there is a wide range of processes acting to produce bedload fluctuations. Sampling the same data set with different sampling intervals yields a near linear relationship between sampling interval and pulse period. A range of modelling strategies has been applied to bed waves. The most successful have been those which allow for the three-dimensional nature of sediment storage processes, and which allow changes in the width and depth of stored sediment. The existence of bed waves makes equilibrium in gravel-bed rivers necessarily dynamic. Bedload pulses and bed waves can be regarded as equilibrium forms at sufficiently long timescales.

Microforms in Gravel Bed Rivers: Formation, Disintegration, and Effects on Bedload Transport

2004 ◽  
Vol 130 (6) ◽  
pp. 554-567 ◽  
Author(s):  
K. Strom ◽  
A. N. Papanicolaou ◽  
N. Evangelopoulos ◽  
M. Odeh
Keyword(s):  
Bedload Transport ◽  
Gravel Bed ◽  
Gravel Bed Rivers

Processes of initiation of motion leading to bedload transport in gravel-bed rivers

2007 ◽  
Vol 34 (6) ◽  
Author(s):  
Celso Garcia ◽  
Hai Cohen ◽  
Ian Reid ◽  
Albert Rovira ◽  
Xavier Úbeda ◽  
...  
Keyword(s):  
Bedload Transport ◽  
Gravel Bed ◽  
Gravel Bed Rivers

scholarly journals Displacement length and velocity of tagged logs in the tagliamento river

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Diego Ravazzolo ◽  
L. Mao ◽  
B. Garniga ◽  
L. Picco ◽  
M.A. Lenzi
Keyword(s):  
Cross Sections ◽  
Positive Relationship ◽  
Transport Processes ◽  
Large Wood ◽  
Flood Events ◽  
Gravel Bed ◽  
North East ◽  
High Magnitude ◽  
Tagliamento River ◽  
Gravel Bed Rivers

Large wood enhance the dynamics of geomorphic processes in river systems, increases the morphological complexity of the channel bed, and provides habitats for fish and invertebrates. On the other side, if transported during high-magnitude events, large wood pieces can increase flood risks in sensitive places such as bridges and narrow cross sections prone to outbank flows. However, the dynamics and mobility of logs in rivers is poorly understood, especially in wide gravel-bed rivers. Recent studies have employed fixed video cameras to assess logs velocity, but little evidence is still available about travel length during flood events of different magnitude. This study was conducted in a valley reach of the Tagliamento river, located in the North East of Italy. The Tagliamento river is approximately 800 m wide in the study area, and is characterized by relatively high natural conditions and complex fluvial dynamics. Log mobility have been studied from June 2010 to October 2011, a period characterized by a relatively high magnitude flood in November 2010. Log mobility and displacement during floods have been measured by implanting active radio transmitters (RFID) in 113 logs and GPS track devices in 42 logs. The first devices allow to recover the log after flood events by using a portable antenna, and to derive the displacement length over the monitoring period, whereas the second devices allows to calculate instantaneous (1 sec) and average log velocity of moving logs. Recovery rate of logs equipped with RFID and GPS was about 50% and 60%, respectively. A preliminary analysis of the data collected indicates that there is a positive relationship between displacement length and the peak of flood events, as well as a positive relationship between log velocity and the flood magnitude. Also, a critical flow rate over which logs stranded on active bars can be transported has been identified. The ability to predict wood mobility in gravel-bed rivers could allow to define better strategies of river management and restoration, by improving the ability to understand wood transport processes and calibrate budgets of wood in rivers.

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