Understanding the entropy-based morphological variability and energy expenditure mechanism of a large braided river system

Nandi, Ketan Kumar; Pradhan, Chandan; Padhee, Suman Kumar; Dutta, Subashisa; Khatua, Kishanjit Kumar

doi:10.1016/j.jhydrol.2022.128662

Cited by 9 publications

(4 citation statements)

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“…The water discharge also shows strong inter‐ and intra‐season variability resulting in dynamic morphology of the floodplains (Nandi, Pradhan, Dutta, & Khatua, 2022; Nandi, Pradhan, Padhee, et al., 2022). The monthly water discharge at Guwahati is 40,000 m 3 /s in monsoon and 5,000 m 3 /s in the dry season (for 1956–1979, Data: Global Runoff Data Center, http://www.compositerunoff.sr.unh.edu).…”

Section: Study Areamentioning

confidence: 99%

Intra‐Seasonal Variability in Sediment Provenance and Transport Processes in the Brahmaputra Basin

et al. 2023

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Sediment composition in modern fluvial settings is commonly assessed regarding spatial but rarely temporal variability, potentially leading to a bias of unknown extent. Here, we present the grain‐size distribution, bulk chemical and mineralogical composition of a time‐series set of 36 suspended sediment samples from the Brahmaputra river, as well as clay and heavy mineral analysis of selected samples. Sampling covers the June–November 2021 period, which included two major flooding events. We show that the two flooding events are characterized by contrasting grain size, with the first event characterized by a grain‐size minimum and the second by a grain‐size maximum. Although grain sizes of the first flood and the period after the second are similar, their compositions differ significantly, highlighted by a factor‐two decrease of biotite largely compensated by an increase in quartz. By contrast, the content of garnet, clinopyroxene, sillimanite, and rutile increased compared to epidote and amphibole during the second flood event. By relating the results to spatio‐temporal rainfall and discharge patterns and basin morphology, we conclude that the first flooding primarily mobilized hydraulically pre‐sorted sediments from the exposed sandbars of the floodplains, while those sandbars are already submerged during the second flooding in a single‐channel system, resulting in higher sediment contributions from highland tributaries draining igneous and high‐grade metamorphic rocks. Such temporal variations pose constraints on the interpretation of compositional differences between individual samples regarding sediment provenance and dispersal and should be considered in studies of modern drainage basins as well as ancient sediment routing systems.

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Section: Study Areamentioning

confidence: 99%

Intra‐Seasonal Variability in Sediment Provenance and Transport Processes in the Brahmaputra Basin

et al. 2023

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“…These bedforms indirectly influence flood and erosion patterns along the river by impacting water levels and flow velocity (Cilli et al, 2021). Regular monitoring of these river features is crucial in order to understand river characteristics and support mathematical modelling (Mosselman, 2004;Spasojevic and Holly, 2008;Williams et al, 2016a;Nandi et al, 2022). Monitoring involves tracking changes in bar position, height, width, and length through river surveys and multi-temporal satellite imagery (Pareta and Pareta, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Previous literature indicates that the recent channel evolution of the Brahmaputra River is primarily influenced by regional tectonics and basin aggradation (Goswami, 1985;Lahiri and Sinha, 2012;Sarker et al, 2014;Czuba and Foufoula-Georgiou, 2015;Basumatary et al, 2019;Li et al, 2020;Cilli et al, 2021;Gao et al, 2022;Nandi et al, 2022;Saikia and Laskar, 2022;Nandi et al, 2023;Pradhan et al, 2023). These factors dictate the residence time of the river or its branches at different locations, with major anabranches and their angles of approach to the banks determining the erosional magnitude of adjacent areas (Coleman, 1969;Basumatary et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The morphodynamics of extensive braided river systems, like the Brahmaputra, contribute to high rates of bank erosion, an unstable braided belt, and fluctuating channel courses (Dutta et al, 2010). The considerable variability in discharge and sediment load leads to extensive erosion-deposition processes and complex bar dynamics (Sah et al, 2022), requiring exploration of spatio-temporal variability in bar dynamics to understand braided hydrodynamics (Nandi et al, 2022). Comprehensive data collection, both vertically and horizontally, is essential for understanding morphological changes in a braided river like the Brahmaputra (Sarker and Thorne, 2006;Li et al, 2020;Saikia and Laskar, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Morphological Model for Erosion Prediction of India’s Largest Braided River Using MIKE 21C Model

Pareta

2024

Earth Sci. Syst. Soc.

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The Brahmaputra River has a dynamic, highly braided channel pattern with frequent river bar formation, making it morphologically very dynamic, especially during the monsoon season with high discharge and sediment load. To understand how the river changes over time, this study focused on two stretches: Palasbari-Gumi and Dibrugarh. Using 2D morphological models (MIKE-21C), the study aimed to predict erosion patterns, plan protective measures, and assess morphological changes over short-term (1 year), medium-term (3 year), and long-term (5 year) periods. Model runs were conducted to predict design variables across these river reaches, encompassing different hydrological scenarios and development-planning scenarios. The coarse sand fraction yielded mean annual sediment load predictions of 257 Mt/year for the 2021 hydrological year and 314 Mt/year under bankfull discharge conditions in the Palasbari-Gumi reach. In the Dibrugarh reach, the corresponding values were 78 Mt/year and 100 Mt/year. Notably, historical records indicate an annual sediment load of 400 Mt/year in the Brahmaputra River. The model results were compared to measurements from Acoustic Doppler Current Profilers (ADCP), showing good accuracy for flow velocities, flood levels, and sediment loads. Discrepancies in peak model velocities compared to ADCP measurements remain consistently below 9% across the majority of recorded data points. The predicted flood levels for the bankfull discharge condition exhibited an outstanding accuracy, reaching nearly 91% at the Palasbari-Gumi site and a notable 95% at the Dibrugarh site. This study has presented a valuable methodology for enhancing the strategic planning and implementation of river training endeavours, particularly within the dynamic and highly braided channels of rivers such as the Brahmaputra River. The approach leverages predictive models to predict morphological changes over a 2–3 years timeframe, contributing to improved river management.

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Numerical Investigation of Various Turbulence Models for a Sinuous Channel with Sand Mining Pit

Maurya,

Nandi,

Modalavalasa

et al. 2023

Lecture Notes in Civil Engineering

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Understanding the entropy-based morphological variability and energy expenditure mechanism of a large braided river system

Cited by 9 publications

References 103 publications

Intra‐Seasonal Variability in Sediment Provenance and Transport Processes in the Brahmaputra Basin

Intra‐Seasonal Variability in Sediment Provenance and Transport Processes in the Brahmaputra Basin

Morphological Model for Erosion Prediction of India’s Largest Braided River Using MIKE 21C Model

Numerical Investigation of Various Turbulence Models for a Sinuous Channel with Sand Mining Pit

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