Obtuse-angle vs. confluent sharp meander bends: insights from the Paraguay-Cuiabá confluence in the tropical Pantanal wetlands, Brazil

Luz, Leandro Domingos; Szupiany, R. N.; Parolin, Mauro; Silva, Aguinaldo; Stevaux, José Cândido

doi:10.1016/j.geomorph.2019.106907

Cited by 11 publications

(6 citation statements)

References 54 publications

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“…A large number of studies in literature have focused on small‐scale channel confluences with small width‐to‐depth ratios ( W / H < 10) (e.g., Baranya et al., 2015; Riley & Rhoads, 2011). More recently, an increasing number of studies have been undertaken to study confluences at medium scale (10 < W / H < 50) (Biron et al., 2019; Konsoer & Rhoads, 2014; Luz et al., 2020; Martín‐Vide et al., 2015; Ramón et al., 2013; Riley et al., 2014) and at large scale ( W / H > 50) (Best & Ashworth, 1997; Gualtieri et al., 2018; Ianniruberto et al., 2018; Lane et al., 2008; Parsons et al., 2007; Szupiany et al., 2009). The main findings from studies on small, medium and large confluences are briefly reviewed.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics, Sediment Transport and Morphological Features at the Confluence Between the Yangtze River and the Poyang Lake

Yuan

Tang

et al. 2021

Water Resources Research

100

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Confluences are critical nodes in a river network and affect flow, sediment transport, water quality, and ecological patterns. Significant changes in hydrodynamics, bed morphology as well as environmental and ecological features occur at the confluence, where the flows from two tributaries combine and adjust to the postconfluence planform geometry. Confluence of two flows with different momentum and velocity ratios (the ratio of the variable of one channel to that of the other) often results in a downstream shear layer driven by the Kelvin-Helmholtz (KH) instability. It enhances turbulent mixing and exchange of momentum and other matter (e.g., sediment and pollutants;

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Section: Introductionmentioning

confidence: 99%

Hydrodynamics, Sediment Transport and Morphological Features at the Confluence Between the Yangtze River and the Poyang Lake

Yuan

Tang

et al. 2021

Water Resources Research

100

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“…The possibilities of the traditional GIS are not sufficient enough for the machine learning approaches in modern mapping as a special category cartographic data processing that combines elements of the programming with traditional data visualization and representation as maps. Hence, the presented cartographic results showed that GMT performed better mapping than traditional GIS that mostly applied the Graphical User Interface (GUI) for operation with data (DA PONTE et al 2017;LEMENKOVA et al 2012;PAINTER et al 2020;LUZ et al 2020;LEMENKOVA, 2020d;FERREIRA DA SILVA et al 2021). In contrast, the GMT-based data processing enables to plot a series of the climate maps of Paraguay using scripting method of machine learning which operates with spatial data in a fast and automated way.…”

Section: Discussionmentioning

confidence: 93%

Comparative analysis of climate and topography in Chaco and Oriental, Paraguay

Lemenkova¹

2021

Cad. Geogr.

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The article reports the issues corresponding to the climate variability and possibility of droughts in spatially distinct regions of Paraguay, the Chaco and the Oriental (Paraná Basin). Based on the GMT scripting approach and high-resolution datasets from the TerraClimate and GEBCO, the study examined the extent of the annual climate and environmental variables over Paraguay in 2020: extreme temperatures, wind speed, precipitation, soil moisture, evapotranspiration, Palmer's Drought Severity Index (PDSI), vapour pressure deficit (VPD) and the topography of the country. The environmental and climate parameters demonstrated spatial variability in the Dry Chaco with notable differences in Gran Chaco and Chaco Boreal, wetlands of Pantanal, and tropical rainforests in east of the Paraguay. Besides climate analysis, technical snippets from the GMT scripts regarding the mapping techniques and data processing were explained and commented. Research results show that actual evapotranspiration reaches maximal values in the Paraná Basin (180 mm/yr), and has peaks along the Pilcomayo river (140-150 mm/yr) which well coincides with the soil moisture; the PDSI values are maximal in Chaco Boreal and Gran Chaco; the temperatures are the highest in the N and NW regions of Paraguay; the highest VPD (over 2.0) corresponds to the Chaco Boreal.

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“…This averaging reduces the influence of outliers and measurement errors for individual transects on patterns of velocities within a cross‐section. Previous work has demonstrated the value of VMT‐based analysis of multiple traverses of ADCP data for identifying patterns of time‐averaged three‐dimensional fluid motion at confluences (Gualtieri et al, 2018; Herrero et al, 2018; Li et al, 2022; Luz et al, 2020; Rhoads & Johnson, 2018; Riley & Rhoads, 2012; Riley et al, 2015; Yuan et al, 2021; Zhang et al, 2020). Secondary velocities ( v s ) based on the Rozovskii method (Rozovskii, 1957), which defines components of secondary flow oriented perpendicular to the direction of the depth‐averaged velocity (

\overset{u}{true}

) at each vertical profile through the flow column, were also determined using VMT.…”

Section: Measurements and Datamentioning

confidence: 99%

“…At asymmetrical confluences, flow from the lateral tributary exhibits the greatest streamline curvature, resulting in a single dominant helical cell within the downstream channel (Rhoads & Kenworthy, 1995). Patterns of helical motion within confluences can be altered by the planform characteristics of the upstream channels, particularly curvature of these channels, which generates helical motion of incoming flows that can extend into the confluence (Luz et al, 2020; Riley & Rhoads, 2012; Riley et al, 2015; Rhoads & Johnson, 2018).…”

Section: Introductionmentioning

confidence: 99%

Spatial patterns of transport‐effective flow at three small confluences: Relation to channel morphology

Shukla

Lewis

Rhoads

2023

Earth Surf Processes Landf

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The spatial patterns of transport‐effective flows at confluences and the relation of these patterns to channel morphology remain poorly understood. This field study uses acoustic Doppler current profiler measurements to explore the spatial structure of different transport‐effective flows at three small stream confluences where measurements of flow structure have been obtained previously using electromagnetic current meters or acoustic Doppler velocimeters for events incapable of mobilizing bed material or for transport‐effective events with much smaller discharges. Results show that flow accelerates from upstream to downstream for all six measured flows and that in each case a distinct region of velocity deficit exists within the confluence. Accelerating flow within this velocity‐deficit region eventually transforms into the high‐velocity core of flow downstream of the confluence. Patterns of secondary flow are indicative of helical motion, with some helical cells exhibiting senses of rotation inconsistent with patterns of streamline curvature defined by patterns of depth‐averaged velocity vectors—a type of fluid motion that contrasts with flow structure documented at lower stages. Channel form, especially bed morphology, generally reflects acceleration of flow at the confluences; all three sites exhibit zones of scour. Despite mobility of bed material during measured flows, channel morphology does not change substantially at any of the sites, but systematic change in channel form for two different transport‐effective events with different momentum flux ratios is observed at one of the three confluences. At this confluence, the type of change documented during the two events is consistent with previous work on changes in morphology before and after events with different momentum flux ratios. The results of this study improve understanding of the connections between flow structure and channel form at small lowland stream confluences.

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Obtuse-angle vs. confluent sharp meander bends: insights from the Paraguay-Cuiabá confluence in the tropical Pantanal wetlands, Brazil

Cited by 11 publications

References 54 publications

Hydrodynamics, Sediment Transport and Morphological Features at the Confluence Between the Yangtze River and the Poyang Lake

Hydrodynamics, Sediment Transport and Morphological Features at the Confluence Between the Yangtze River and the Poyang Lake

Comparative analysis of climate and topography in Chaco and Oriental, Paraguay

Spatial patterns of transport‐effective flow at three small confluences: Relation to channel morphology

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