How Is Time Distributed in a River Meander Belt?

Ielpi, Alessandro; Viero, Daniele Pietro; Lapôtre, M. G. A.; Graham, A.; Ghinassi, Massimiliano; Finotello, Alvise

doi:10.1029/2022gl101285

Cited by 9 publications

(5 citation statements)

References 48 publications

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“…Meander cutoffs form when meanders laterally migrate into upstream or downstream reaches of the same river. Therefore, the amount of time needed to produce a cutoff is proportional to lateral migration rate (Ielpi et al., 2023). Our quantification of cutoff occurrence is consistent with variability in cutoffs that have previously been documented along the Red River (Phillips, 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Here we quantify the change in slope along the Red River since 8.5 ka due to GIA, and test if spatial trends in slope change correlate to geomorphic evidence for varying migration rates. Specifically, we compare modeled slope change to a record of cutoff occurrence, a proxy for lateral migration rate (Ielpi et al., 2023), and assess the statistical significance of their relationship by performing a Monte Carlo ensemble of M ‐estimator linear regressions. To generalize our findings, we also consider two additional tributary river systems in this region, the Assiniboine and Red Lake Rivers.…”

Section: Introductionmentioning

confidence: 99%

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Glacial Isostatic Adjustment Modulates Lateral Migration Rate and Morphology of the Red River (North Dakota, USA and Manitoba, Canada)

Kodama

Pico

Finnegan

et al. 2023

Geophysical Research Letters

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The lateral migration of a river meander is driven by erosion on the outer bank and deposition on the inner bank, both of which are affected by shear stress (and therefore channel slope) through complex morphodynamic feedbacks. To test the sensitivity of lateral migration to channel slope, we quantify slope change induced by glacial isostatic adjustment along the Red River (North Dakota, USA and Manitoba, Canada) and two of its tributaries over the past 8.5 ka. We demonstrate a statistically significant, positive relationship between normalized cutoff count, which we interpret as a proxy for channel lateral migration rate, and slope change. We interpret this relationship as the signature of slope change modulating the magnitude of shear stress on riverbanks, suggesting that slope changes that occur over thousands of years are recorded in river floodplain morphology.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glacial Isostatic Adjustment Modulates Lateral Migration Rate and Morphology of the Red River (North Dakota, USA and Manitoba, Canada)

Kodama

Pico

Finnegan

et al. 2023

Geophysical Research Letters

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“…It shows that bend expansion and translation were the primary modes for cutoff formation. During the lifetime of a meandering river, where migration and cutoffs interact in space and time, dynamic-equilibrium conditions occur and morphometrics (such as sinuosity, lateral migration rates, and rate of cutoff occurrence) reach their statistical steady-states Vermeulen et al, 2016;Ruben-Dominguez et al, 2021;Ielpi et al, 2023). Given the recurring and profound social-ecological impacts caused by the occurrence of channel cutoffs in meandering rivers (Abad et al, 2022;Nagel et al, 2022), fluvial geomorphologists have developed theories and tools to help explain this process (Stølum, 1996;Edwards and Smith, 2002;Camporeale et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

High-resolution modeling of meander neck cutoffs: laboratory and field scales

Li,

Mendoza,

Abad

et al. 2023

Front. Earth Sci.

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Meandering rivers are distinguished by their characteristic sinuosity, which is subject to modulation through channel cutoff, resulting in the formation of oxbow lakes within the abandoned meander loops. Throughout the evolutionary course of a river, these cutoffs establish a connection between the channel and floodplain systems, both crucial to maintaining the dynamic equilibrium of the river system. Nonetheless, the interactive dynamic between the channel and floodplain and its influence on the transient behavior of the channel’s morphodynamics during a cutoff event are frequently reduced to simplistic representations in computational models. This study introduces a comprehensive numerical model that elucidates the adaptive processes of bed and planform during and subsequent to the inception of cutoff and oxbow lakes. The model is assessed through its application to a laboratory scale cutoff, before being employed to a real-world meandering river, specifically the Ucayali River in Peru, in order to gain understanding into channel development and the intricate patterns of planform dynamics following cutoff events. The model is able to capture the main modes of planform migration, translation and expansion for the case of the bend in the Ucayali River. During the neck cutoff, the model simulates the progression of erosional and depositional waves traveling in upstream and downstream directions respectively, underscoring the importance of incorporating both hydrodynamic and morphodynamic factors in characterizing the river dynamics associated with meander cutoffs.

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“…Rivers regularly erode and remobilize channel and floodplain sediments. Therefore, sediment residence times are variable but generally predictable with regard to probability distributions across floodplains (Ielpi et al, 2023). Alluvial deposits comprising fill terraces have a greater potential for long-term storage because they are detached from active channel processes.…”

Section: Introductionmentioning

confidence: 99%

Telescopic Megafans on the High Plains, USA Were Signal Buffers in a Major Source-To-Sink System

Korus,

Joeckel

2023

The Sedimentary Record

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Sediment routing systems transport sediment and environmental signals inefficiently. The storage and recycling of sediment buffers the responses of sedimentary systems to tectonic, climatic, and geomorphic changes. Long-term ( >106 a.) storage may occur in megafans—large, low-relief, hemiconical fluvial deposystems—but the behavior of these systems over such timescales is unclear. We examine late Neogene megafan deposits on the High Plains, USA that are stored in the catchment of the continental-scale Rocky Mountain-Gulf of Mexico source-to-sink system. Using high-resolution elevation data, we map numerous fluvial ridges (inverted channel relics) that can be differentiated into five, chronologically distinct groups. The oldest four groups comprise radial arrays with multiple channel divergences (avulsion nodes). The inferred fan apices and longitudinal intersection points are offset successively downgradient, indicating that fanhead entrenchment and fan-lobe deposition were approximately contemporaneous and strongly suggesting a telescopic morphology. The youngest group of channels, also the lowest in elevation, is confined to terraces along the modern valley of the South Platte River. We interpret this group as direct evidence for the abandonment of the megafan and the incision of the present valley. Uplift was the chief driving mechanism for early telescoping, but channel widening and uniform downcutting in the younger groups suggest that change in stream power was the primary driver of later telescoping and incision. The storage of sediment in the megafan effectively decoupled sources from downstream sinks. Some of this sediment was recycled during entrenchment, but much of it remains in storage as the Ogallala Group and Broadwater Formation. Emplacement of telescopic megafans should be considered as a long-term ( ≥106 years) buffer in other modern and ancient sediment routing systems.

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How Is Time Distributed in a River Meander Belt?

Cited by 9 publications

References 48 publications

Glacial Isostatic Adjustment Modulates Lateral Migration Rate and Morphology of the Red River (North Dakota, USA and Manitoba, Canada)

Glacial Isostatic Adjustment Modulates Lateral Migration Rate and Morphology of the Red River (North Dakota, USA and Manitoba, Canada)

High-resolution modeling of meander neck cutoffs: laboratory and field scales

Telescopic Megafans on the High Plains, USA Were Signal Buffers in a Major Source-To-Sink System

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