Evolutionary, multi-scale analysis of river bank line retreat using continuous wavelet transforms: Jamuna River, Bangladesh

Mount, Nick J.; Tate, Nicholas; Sarker, Maminul Haque; Thorne, Colin R.

doi:10.1016/j.geomorph.2012.07.017

Cited by 50 publications

(23 citation statements)

References 57 publications

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“…Better results may be obtained using physically‐based hydrological models nowadays available at catchment scales (Barker et al ., ). We also encourage the implementation of other discharge metrics: for example, major floods with higher return periods, which strongly affect erosion processes (Mount et al ., ). That would enhance our understanding of how flow regimes affect erosional and depositional processes.…”

Section: Discussionmentioning

confidence: 99%

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

2013

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Stream power is a measure of the main driving forces acting in a channel and determines a river's capacity to transport sediment and perform geomorphic work. Recent digital elevation models allow the calculation of channel gradient and consequently stream power at unprecedented spatial resolution, opening promising and novel opportunities to investigate river geomorphic processes and forms. The present paper investigates the suitability of map‐derived information on total and specific stream power (SSP) to identify dominant processes within the channel (i.e. erosion, transport or deposition). SSP has been already used to identify a threshold for channel stability. This paper tests this knowledge and investigates whether or not attributes of stream power profiles are statistically correlated with distinctive field morphological forms. Two gravel bed single‐thread English rivers are used as case studies, the Lune and the Wye. Available deposition and erosion features surveyed in the field from 124 different locations are used to classify channel reaches as erosion, transport or deposition dominated. Meaningful patterns emerge between the stream power attributes and the field‐based channel classification. An SSP threshold, which erosion is triggered, compares favourably with the ones in the literature. Information about upstream stream power profiles helps to determine the dominant processes. The joint configuration of local and upstream stream power information uniquely classifies reaches into four classes of different sensitivity to erosion and deposition. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

2013

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“…For details, reader can refer to the work by Torrence and Compo 28 . CWT was successfully applied by Mount et al 29 for bank erosion scale analysis. Mount et al 29 concluded that out of three different basis functions, the Morlet function with order 3 was the best, that clearly resolves different spatial scales.…”

Section: Methodsmentioning

confidence: 99%

“…CWT was successfully applied by Mount et al 29 for bank erosion scale analysis. Mount et al 29 concluded that out of three different basis functions, the Morlet function with order 3 was the best, that clearly resolves different spatial scales. Therefore, in this study, we used Morlet as the basis function …”

Section: Methodsmentioning

confidence: 99%

Study of Channel Instability in the Braided Brahmaputra River Using Satellite Imagery

Karmaker¹,

Medhi²,

Dutta³

2017

Current Science

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In the present study, instability of the river reach of Brahmaputra was analysed for braided belt width changes, braiding index and bar area. The river reach of the Brahmaputra from its confluence of Lohit, Dibang and Dihang to its confluence with the Tista river was studied from 1973 to 2009. The study was carried out using remotely sensed data from Landsat satellites at different dates. Discharge data synchronized with satellite data was collected by maintaining near-similar water level or discharge. Wavelet of the braided belt change was analysed to get the wavelet power and spatial extent of the changes. Finally, stream power was analysed from the average discharge data during the monsoon period to determine its effect on the instability of parameters considered. Results indicate that stream power does not directly relate to local changes in the braided belt or braiding index. However, with decrease in stream power, an increasing trend of bar area was found. Maximum wavelet power within a period showed a threshold behaviour at stream power of 5 W/km, beyond which the wavelet power raised sharply to a high value with increase in stream power. River response to the stream power was found at a global level rather than local level. Finally, a gradual decrease in stream power over time indicates the stable river reach. However, changes due to local bank erosion cannot be predicted using this analysis.

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“…With recent advances in remote sensing, the planform characteristics and decadal evolution of large rivers can be described in greater detail (Ashworth and Lewin, 2012;Trigg et al, 2012;Lewin and Ashworth, 2014a), and the temporal morphodynamics of large rivers can be quantified (e.g. Mount et al, 2013). With over four decades of global imagery now available from programmes such as NASA's Landsat, there is thus a great opportunity to study the morphodynamics of large river confluences over decadal timescales.…”

Section: Introductionmentioning

confidence: 99%

The Planform Mobility of River Channel Confluences: Insights from Analysis of Remotely Sensed Imagery

Dixon¹,

Smith²,

Best³

et al. 2017

Preprint

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A B S T R A C TRiver channel confluences are widely acknowledged as important geomorphological nodes that control the downstream routing of water and sediment, and which are locations for the preservation of thick fluvial deposits overlying a basal scour. Despite their importance, there has been little study of the stratigraphic characteristics of river junctions, or the role of confluence morphodynamics in influencing stratigraphic character and preservation potential. As a result, although it is known that confluences can migrate through time, models of confluence geomorphology and sedimentology are usually presented from the perspective that the confluence remains at a fixed location. This is problematic for a number of reasons, not least of which is the continuing debate over whether it is possible to discriminate between scour that has been generated by autocyclic processes (such as confluence scour) and that driven by allocyclic controls (such as sea-level change). This paper investigates the spatial mobility of river confluences by using the 40-year record of Landsat Imagery to elucidate the styles, rates of change and areal extent over which large river confluence scours may migrate. On the basis of these observations, a new classification of the types of confluence scour is proposed and applied to the Amazon and Ganges-Brahmaputra-Meghna (GBM) basins. This analysis demonstrates that the drivers of confluence mobility are broadly the same as those that drive channel change more generally. Thus in the GBM basin, a high sediment supply, large variability in monsoonal driven discharge and easily erodible bank materials result in a catchment where over 80% of large confluences are mobile over this 40-year window; conversely this figure is < 40% for the Amazon basin. These results highlight that: i) the potential areal extent of confluence scours is much greater than previously assumed, with the location of some confluences on the Jamuna (Brahmaputra) River migrating over a distance of 20 times the tributary channel width; ii) extensive migration in the confluence location is more common than currently assumed, and iii) confluence mobility is often tied to the lithological and hydrological characteristics of the drainage basins that determine sediment yield.

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Evolutionary, multi-scale analysis of river bank line retreat using continuous wavelet transforms: Jamuna River, Bangladesh

Cited by 50 publications

References 57 publications

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

Study of Channel Instability in the Braided Brahmaputra River Using Satellite Imagery

The Planform Mobility of River Channel Confluences: Insights from Analysis of Remotely Sensed Imagery

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