Meandering Morphodynamics: Insights from Laboratory and Numerical                    Experiments and Beyond

Silva, Ana Maria Ferreira da; Ebrahimi, Mohsen

doi:10.1061/(asce)hy.1943-7900.0001324

Cited by 29 publications

(14 citation statements)

References 71 publications

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“…This motion of sediment is due to the established secondary currents in bends. Previous studies [8,10,15] have already focused on the The morphological changes are also analyzed along a bend of the sinuous channel. The variations in an alluvial bed are visible in the channel.…”

Section: Resultsmentioning

confidence: 99%

Deciphering Morphological Changes in a Sinuous River System by Higher-Order Velocity Moments

Taye

Barman

Kumar

et al. 2020

Water

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Bank erosion in a sinuous alluvial channel is a continuous phenomenon resulting in bank instability and migration of sediment. In this study, flume experiments were conducted in a sinuous channel to investigate its morphological changes and hydrodynamics. High-order velocity fluctuation moments are analyzed at outer and inner banks to explain the morphological variation in a sinuous river channel. The variance of streamwise velocity fluctuations on both banks of the sinuous channel follows a logarithmic law from a particular depth. In the outer bend region, the magnitude of velocity fluctuation moment is significant, indicating erosion. The trend of velocity fluctuation at higher even-order moments is similar to the variance of streamwise velocity fluctuations where the outer bend magnitude is greater than the inner bend. The premultiplied probability density functions (PDFs) and the flatness factor show greater magnitude in the outer bend of the channel as compared to the inner bend.

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Section: Resultsmentioning

confidence: 99%

Deciphering Morphological Changes in a Sinuous River System by Higher-Order Velocity Moments

Taye

Barman

Kumar

et al. 2020

Water

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“…Meanders are systems that are constantly changing, following a sinusoidal pattern, and playing an important role in the modelling and shaping of the landscape around them. These beautiful patterns have been the object of study of many researchers in diverse areas in the last 50 years [34][35][36][37][38]. Two main processes in meander migration are bank erosion and bank accretion [34,35,39].…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Bathymetric Survey and Topography Changes Investigation of Part of Badagry Creek and Yewa River, Lagos State, Southwest Nigeria

Badejo

Adewuyi

2019

JGEESI

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Bathymetry survey of Part of Badagry Creek and Yewa River was conducted with the aim of investigating the topography changes in depth between two epoch dataset by calculating the volume of sediment and dredged material between the two periods. Depth sounding at 100m interval, data grid of 100 m interval, constant vessel speed of 2.2 m/secs (8Km/hr) for data capture, data storage at interval of 30 Secs was ensured at both the creek and the river. Seabed topography changes of Part of Badagry Creek and Yewa River was investigated. The two dataset investigated was the data acquired in September 2008 and November 2015. Data acquisition was done using digital echo sounder SDE28, Handheld Real time Kinematic (RTK) Global Positioning System (GPS) in acquiring the spatial coordinates (x, y) and water depth (z). Six (6) wrecks (Shipping Boat) were determined along both the creek and the river. The initial processing was carried out with the use of HYPACK 2008 software for data sorting. ArcGIS 10.2.1 was used for data analysis as well as graphics design. The processed depths were presented in form of tables, map/plan and charts. 2The result showed that In 2008, the depth observed ranges from (-0.5 to 10.4) m while in 2015, the depth observed ranges from (-0.32 to 10.85) m which implies that some area have been cut. Also, the results of the volume of deposited sediments and dredged material are computed as 10.55 x 106 m3 and 7.24 x 106 m3. It showed from the result that volume of accreted sediment is greater than volume of the material dredged. Increase in volume of sediment deposited could be as a result of the adjoining river Yewa flowing into the larger river (tributaries) of the Badagry Creek. Therefore, further studies need to carry out in order to know the source of accreted mass through integrated coastal management plan.

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“…For SF, Youden's J only increases by 5.3% when varying parameter values spatially, which suggests more homogeneous soil characteristics at the SF field site, relative to MC. The suggestion to integrate floodplain heterogeneity into planform evolution models [26] would not only serve in improving the fit between observations and simulation results but would make the model more independent of input parameter values; the parameter set would remain valid throughout a simulation. However, care is required to avoid overfitting a model, which would otherwise compromise its capacity to be validated against a second dataset.…”

Section: Discussionmentioning

confidence: 99%

“…Previous laboratory studies also used cohesive substrate, such as clay (e.g., [21][22][23]). However, most modelling (e.g., [4,24]) and flume-based studies (e.g., [25,26]) on meandering rivers involve sand beds and banks, whereas the meandering process typically occurs in cohesive floodplains [27]. In particular, the mechanisms responsible for the development of meandering channels in a laboratory channel (e.g., [2]) may differ from those observed in nature, even if these channels share similar physiological traits.…”

Section: Introductionmentioning

confidence: 99%

Comparing the Sensitivity of Bank Retreat to Changes in Biophysical Conditions between Two Contrasting River Reaches Using a Coupled Morphodynamic Model

Rousseau

Biron

Wiel

2018

Water

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Morphodynamic models of river meandering patterns and dynamics are based on the premise that the integration of biophysical processes matching those operating in natural rivers should result in a better fit with observations. Only a few morphodynamic models have been applied to natural rivers, typically along short reaches, and the relative importance of biophysical parameters remains largely unknown in these cases. Here, a series of numerical simulations were run using the hydrodynamic solver TELEMAC-2D, coupled to an advanced physics-based geotechnical module, to verify if sensitivity to key biophysical conditions differs substantially between two natural meandering reaches of different scale and geomorphological context. The model was calibrated against observed measurements of bank retreat for a 1.5 km semi-alluvial meandering reach incised into glacial till (Medway Creek, Ontario, Canada) and an 8.6 km long sinuous alluvial reach of the St. François River (Quebec, Canada). The two river reaches have contrasting bed and bank composition, and they differ in width by one order of magnitude. Calibration was performed to quantify and contrast the contribution of key geotechnical parameters, such as bank cohesion, to bank retreat. Results indicate that the sensitivity to key geotechnical parameters is dependent on the biophysical context and highly variable at the sub-reach scale. The homogeneous sand-bed St. François River is less sensitive to cohesion and friction angle than the more complex Medway Creek, flowing through glacial-till deposits. The latter highlights the limits of physics-based models for practical purposes, as the amount and spatial resolution of biophysical parameters required to improve the agreement between simulation results and observations may justify the use of a reduced complexity modelling approach.

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Meandering Morphodynamics: Insights from Laboratory and Numerical Experiments and Beyond

Cited by 29 publications

References 71 publications

Deciphering Morphological Changes in a Sinuous River System by Higher-Order Velocity Moments

Deciphering Morphological Changes in a Sinuous River System by Higher-Order Velocity Moments

Bathymetric Survey and Topography Changes Investigation of Part of Badagry Creek and Yewa River, Lagos State, Southwest Nigeria

Comparing the Sensitivity of Bank Retreat to Changes in Biophysical Conditions between Two Contrasting River Reaches Using a Coupled Morphodynamic Model

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