scholarly journals Reconnaissance of sediment transport and channel morphology in the Lower Rio Bermejo Basin, Argentina - with a section on reconnaissance of the lower Rio Pilcomayo Basin, Argentina and Paraguay

1976 ◽  
Author(s):  
John R. Ritter
Keyword(s):  
Sediment Transport ◽  
Channel Morphology ◽  
Bermejo Basin

scholarly journals Sediment transport at the network scale and its link to channel morphology in the braided Vjosa River system

2021 ◽  
Author(s):  
Simone Bizzi ◽  
Marco Tangi ◽  
Rafael J. P. Schmitt ◽  
John Pitlick ◽  
Hervé Piégay ◽  
...  
Keyword(s):  
Sediment Transport ◽  
River System ◽  
Channel Morphology ◽  
Network Scale

scholarly journals A reduced-complexity model for sediment transport and step-pool morphology

2016 ◽  
Author(s):  
Matteo Saletti ◽  
Peter Molnar ◽  
Marwan A. Hassan ◽  
Paolo Burlando
Keyword(s):  
Sediment Transport ◽  
Channel Morphology ◽  
Sediment Supply ◽  
Physically Based ◽  
Load Transport ◽  
Physically Based Models ◽  
Bed Load Transport ◽  
Transport Particle ◽  
Reduced Complexity ◽  
Complex Phenomena

Abstract. A new particle-based reduced-complexity model, CAST, to simulate sediment transport and channel morphology in steep streams is presented. CAST contains phenomenological parameterizations, deterministic or stochastic, of sediment supply, bed load transport, particle entrainment and deposition in a cellular-automaton space with uniform grain size. The model can reproduce a realistic bed morphology and typical fluctuations in transport rates observed in steep channels. Particle hop distances, from entrainment to deposition, are well-fitted by exponential distributions, in agreement with field data. The effect of stochasticity both in the entrainment and in the input rate is shown. A stochastic parameterization of the entrainment is essential to create and maintain a realistic channel morphology, while sediment transport in CAST shreds the input signal and its stochastic variability. A jamming routine has been added to CAST to simulate the grain-grain and grain-bed interactions that lead to particle jamming and step formation in a step-pool stream. The results show that jamming is effective in generating steps in unsteady conditions. Steps are created during high- flow periods and they survive during low flows only in sediment- starved conditions, in agreement with the jammed-state hypothesis of Church and Zimmermann (2007). Reduced-complexity models such as CAST can give new insight into the dynamics of complex phenomena (such as sediment transport and bedform stability) and be useful to test research hypotheses, being an effective complement to fully physically-based models.

SEDIMENT TRANSPORT AND CHANNEL MORPHOLOGY OF SMALL, FORESTED STREAMS

2005 ◽  
Vol 41 (4) ◽  
pp. 853-876 ◽  
Author(s):  
Marwan A. Hassan ◽  
Michael Church ◽  
Thomas E. Lisle ◽  
Francesco Brardinoni ◽  
Lee Benda ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Channel Morphology

scholarly journals A reduced-complexity model for sediment transport and step-pool morphology

2016 ◽  
Vol 4 (3) ◽  
pp. 549-566 ◽  
Author(s):  
Matteo Saletti ◽  
Peter Molnar ◽  
Marwan A. Hassan ◽  
Paolo Burlando
Keyword(s):  
Sediment Transport ◽  
Cellular Automaton ◽  
Channel Morphology ◽  
Sediment Supply ◽  
Physically Based ◽  
Load Transport ◽  
Physically Based Models ◽  
Bed Load Transport ◽  
Reduced Complexity ◽  
Complex Phenomena

Abstract. A new particle-based reduced-complexity model to simulate sediment transport and channel morphology in steep streams in presented. The model CAST (Cellular Automaton Sediment Transport) contains phenomenological parameterizations, deterministic or stochastic, of sediment supply, bed load transport, and particle entrainment and deposition in a cellular-automaton space with uniform grain size. The model reproduces a realistic bed morphology and typical fluctuations in transport rates observed in steep channels. Particle hop distances, from entrainment to deposition, are well fitted by exponential distributions, in agreement with field data. The effect of stochasticity in both the entrainment and the input rate is shown. A stochastic parameterization of the entrainment is essential to create and maintain a realistic channel morphology, while the intermittent transport of grains in CAST shreds the input signal and its stochastic variability. A jamming routine has been added to CAST to simulate the grain–grain and grain–bed interactions that lead to particle jamming and step formation in a step-pool stream. The results show that jamming is effective in generating steps in unsteady conditions. Steps are created during high-flow periods and they survive during low flows only in sediment-starved conditions, in agreement with the jammed-state hypothesis of Church and Zimmermann (2007). Reduced-complexity models like CAST give new insights into the dynamics of complex phenomena such as sediment transport and bedform stability and are a useful complement to fully physically based models to test research hypotheses.

Assessing riparian zone impacts on water and sediment movement: a new approach

2012 ◽  
Vol 91 (1-2) ◽  
pp. 245-255 ◽  
Author(s):  
S.D. Keesstra ◽  
E. Kondrlova ◽  
A. Czajka ◽  
M. Seeger ◽  
J. Maroulis
Keyword(s):  
Sediment Transport ◽  
Flow Velocity ◽  
Riparian Vegetation ◽  
Stream Flow ◽  
Riparian Zone ◽  
Channel Morphology ◽  
Channel Management ◽  
Water And Sediment ◽  
The Impact ◽  
Natural Channel

AbstractThe state of river channels and their riparian zones in terms of geomorphology and vegetation has a significant effect on water and sediment transport in headwater catchments. High roughness in natural rivers due to vegetation and geomorphological attributes generate drag on flowing water. This drag will slow water discharge, which in turn influences the sediment dynamics of the flow. The impacts of changes in the management of rivers and their riparian zone (either by catchment managers or river restoration plans) impacts both up- as well as downstream reaches, and should be assessed holistically prior to the implementation of these plans.To assess the river's current state as well as any possible changes in geomorphology and vegetation in and around the river, effective approaches to characterise the river are needed. In this paper, we present a practical approach for making detailed surveys of relevant river attributes. This methodology has the benefit of being both detailed – describing river depth, width, channel morphology, erosive features and vegetation types – but also being practical in terms of time management. This is accomplished by identifying and describing characteristic benchmark reaches (typical sites) in detail against which the remainder of the river course can be rated. Using this method, a large river stretch can be assessed in a relatively short period while still retrieving high quality data for the total river course. In this way, models with high data requirements for assessing the condition of a river course, can be parameterised without major investments on field surveys.In a small headwater catchment (23 km2) in southwestern Poland, this field methodology was used to retrieve data to run an existing model (HEC-GeoRAS) which can assess the impact of changes in the riparian and channel vegetation and channel management on sedimentation processes and stream flow velocity. This model determines the impact of channel morphology and in-channel and riparian vegetation on stream flow and sediment transport. Using four return periods of flooding (2, 10, 20 and 100 years), two opposing channel management / morphology scenarios were run; a natural channel and a fully regulated channel. The modelling results show an increase in the effect of riparian vegetation / geomorphology with an increase in return period of the modeled peak discharge. More natural channel form and increased roughness reduces the stream flow velocity due to increasing drag from flow obstructions (vegetation and channel morphological features). The higher the flood water stage, the greater the drag due to vegetation on the floodplains of natural river reaches compared to channelised sections. Slower flow rates have an impact on sediment mobilisation and transport in the river.

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