Interaction between the braided bar and adjacent channel during flood: a case study of a sand-bed braided river, Brahmaputra–Jamuna

Shampa,; Ali, Md. Liakot

doi:10.1007/s40899-018-0269-x

Cited by 20 publications

(18 citation statements)

References 24 publications

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“…There are 1194 grid cells in the longitudinal direction and 414 grid cells in the transverse direction. The quantity and resolution of grids in this study are improved compared to previous reach‐scale studies on natural braided rivers, such as 185 m × 95 m for a 220 km reach of the Brahmaputra–Jamuna (Shampa & Ali, 2019) and 100 m × 100 m for a 65 km reach of the Brahmaputra River (Masbahul et al, 2022). We adopt the domain‐decoupled parallel calculations (Deltares, 2014) in this study for computational efficiency.…”

Section: Methodsmentioning

confidence: 96%

“…However, physics‐based simulation for natural braiding remains difficult and uncommon (Schuurman et al, 2018; Williams et al, 2016). Some studies are limited by computational capability so that only a small study area is simulated (Javernick et al, 2016; Williams et al, 2016) or a relatively coarse grid is applied (Karmaker & Dutta, 2016; Shampa & Ali, 2019). Some other studies have modelled natural river reaches with a comparatively low BI (Schuurman et al, 2018; Wang et al, 2008), which has a weak representation for studying the channel‐network dynamics of high braiding intensity (Kleinhans & Van Den Berg, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Large‐scale modelling of highly braided and laterally confined reach of a sand‐bed river

Han

Sun

Lin

et al. 2023

Earth Surf Processes Landf

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Morphological processes in sand‐bed braided rivers are highly complicated and dynamic, and it is challenging to fully comprehend and predict them quantitatively or even qualitatively. In this paper, we report the application of a physics‐based model with a single sediment fraction (D50 = 0.23 mm), based on field data, to simulate the morphodynamic processes of a large‐scale braided system in a wide valley of the middle Yarlung Tsangpo River in China. The model is capable of reproducing the evolution of large braided patterns at both microscopic and macroscopic scales, and simulating the formation of a high‐intensity braided reach from an initial lateral flat bed under lateral valley confinement. A narrow strip zone of braided corridor presents long‐term concentrated anabranches in the wide valley reach. Moreover, sensitivity analyses suggest that physics‐based modelling can simulate the multi‐thread river pattern even with relatively coarse grids and a large morphological acceleration factor. The model results show that active riverbed movement occurs and additional chutes are encouraged during flooding, while rising water level makes subchannels merge so that the statistical braiding index decreases. Conversely, only about 40% of the total channels are active in transporting sediment at low‐discharge stages, resulting in a local and slow bed scouring. The planimetric confinement of width variations and valley curvatures acts as a primary control on the local braided corridor and the forced bar assemblages. Width variations restrict the section‐average stream power for a given discharge event, while valley curvatures regulate velocity distribution through several control points. Moreover, the activities of riparian vegetation and sandstorm can interfere with the ability of rivers to braid in the corridor area, which requires much more attention in the follow‐up research.

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Section: Methodsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Large‐scale modelling of highly braided and laterally confined reach of a sand‐bed river

Han

Sun

Lin

et al. 2023

Earth Surf Processes Landf

View full text Add to dashboard Cite

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“…The fluvial processes of the Brahmaputra River and its tributaries continuously alter the floodplains, at times to an undesired magnitude (Sarma and Phukan, 2004;Kotoky et al, 2005Kotoky et al, , 2012Das et al, 2012;Lahiri and Sinha, 2012). The river regularly inundates and erodes owing to high orographic precipitation on a narrow drainage basin (Shampa and Ali, 2019). The BFP experienced high magnitude floods in 1954, 1962, 1972, 1977, 1984, 1988, 1998, 2002, 2004, 2012, and 2020 over the past half-a-century.…”

Section: Methodsmentioning

confidence: 99%

Climate change impacts on socio-hydrological spaces of the Brahmaputra floodplain in Assam, Northeast India: A review

et al. 2022

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Intensification of the water cycle mediated by global warming increases the risk of hydrological disasters by modifying precipitation patterns across the globe which leads to adverse socio-economic impacts, especially in developing countries. Socio-hydrological spaces in the vicinity of major river systems are prone to the devastating effects of hydrological disasters yet attract human settlements due to the availability of fertile lands that support agriculture. The Brahmaputra floodplain (BFP) of Assam in Northeast India (NEI) is one such region that supports a high population in spite of being ravaged by annual floods and occasional droughts. The current study attempts to critically review the climate change impacts on socio-hydrological spaces of the BFP exploring climate change-hazard-lives and livelihood linkages of floodplain dwellers. This work utilizes peer reviewed articles along with reports of government and international/national organizations to critically appraise the following-(i) existing climate and fluvial hazard scenario in the BFP, (ii) impacts of climate change on the fluvial hazard and agriculture in the BFP, and (iii) the adaptation and mitigation measures that exist in the BFP. Shifts in the long-term trends of temperature and rainfall have occurred over this region leading to speculations on future scenarios of hydrological hazards and their impacts. Studies project an alteration in the hydrology and flow regime of the Brahmaputra River under climate warming scenarios which will influence the hazard characteristics with implications for agriculture and food security. Integrating disaster risk reduction with agricultural management can provide better climate resilience to the farming communities in the BFP.

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“…Their results confirmed that erosion and deposition were in total greater during the receding phase than during the rising phase of the discharge hydrographs. Moreover, Shampa (2019) also used this model to study the interaction between the braided bar and adjacent channel during a flood. Their 2D model could reproduce the major physical processes that are responsible for the growth of the bar in a braided river.…”

Section: Introductionmentioning

confidence: 99%

Temporal variation of braided intensity and morphodynamic changes in a regulated braided river using 2D modeling and satellite images

Balouchi,

Rüther,

Schwarzwälder

2024

River Research & Apps

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The river morphology of a braided‐type river is rather complex. High sediment transport rates and frequently changing discharges are the cause of dynamic planform evolution. Over the past few decades, scientific attention has been directed toward understanding the coexistence of alternating bars and the consequent emergence of confluences and divergences, all of which interact intricately with the process of bank erosion. It is still rather challenging to estimate or predict the total sediment transport rate in this type of river, especially by considering various hydrologic data and climate effects. This study is focused on the reach of the Devoll River in Albania, located upstream of the Banja dam. Understanding the morphodynamics of this river reach holds significance due to the expanding delta upstream of the dam reservoir. The objectives of the two‐dimensional depth‐averaged approach of the present study are to investigate the temporal variation of braided intensity of Devoll River and the effect of using a discharge hydrograph from hydrologic data compared to the regulated one from the upstream dam on the morphodynamics and sediment transport of the river. After evaluating various parameters such as 11 different sediment transport functions, the best results were reached for a cell size of 5 × 5 m2, Manning roughness coefficient of 0.03, Meyer‐Peter and Müller's sediment function, Hayashi et al. (1980) hiding function, and Van Rijn bed roughness predictor in this study. In addition, the results of comparing satellite images and modeling the river from 2019 to 2023 show that the braided index decreased, and this can be due to the fact that the real scenario of the river has a regulated discharge compared to the non‐regulated discharge from hydrologic data, in the mentioned period.

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Interaction between the braided bar and adjacent channel during flood: a case study of a sand-bed braided river, Brahmaputra–Jamuna

Cited by 20 publications

References 24 publications

Large‐scale modelling of highly braided and laterally confined reach of a sand‐bed river

Large‐scale modelling of highly braided and laterally confined reach of a sand‐bed river

Climate change impacts on socio-hydrological spaces of the Brahmaputra floodplain in Assam, Northeast India: A review

Temporal variation of braided intensity and morphodynamic changes in a regulated braided river using 2D modeling and satellite images

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