Planform Dynamics and Cut-Off Processes in the Lower Ucayali River, Peruvian Amazon

Abad, J. D.; Mendoza, Alberto Bujardón; Arceo, Kristin; Torres, Zara; Valverde, Henry; Medina, Gerles; Frias, C. E.; Berezowsky, Moisés

doi:10.3390/w14193059

Cited by 7 publications

(13 citation statements)

References 32 publications

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“…Modern meandering and anabranching river dynamics of the Ucayali and Marañon rivers were previously characterized by , ), Frias et al (2015, Mendoza et al (2016) and Abad et al (2022a). Figure 2 shows the planform configuration for upstream-(A1) and downstream-skewed (A2) meandering channels (Abad and Garcia, 2009a;Abad and Garcia, 2009b).…”

Section: Modern River Dynamicsmentioning

confidence: 88%

“…The Santa Cruz cutoff occurred in 2018 producing an upstream erosional wave (Abad et al, 2012) that accelerated the Progresso cutoff in 2021. Figures 3G, I show two recent cutoffs along the Ucayali River (Abad et al, 2022a), unveiling a potential cutoff near Jenaro Herrera town (see Figure 3H).…”

Section: Modern and Ancient River Dynamicsmentioning

confidence: 97%

“…Figure 1E shows that the P-S wetland includes different river systems: self-formed meandering (Ucayali, Huallaga, Tigre, Tapiche, Puinahua), underfit-scavenger-formed meandering (Yanayacu, Frontiers in Environmental Science frontiersin.org Pacaya, Samiria), and anabranching (Marañon, Amazonas). The Huallaga, Ucayali, and Tapiche Rivers enter the P-S wetland with an increase in the valley angle-50, 55, and 70 °, respectively, thus avulsion processes and meandering migration rates are enhanced (Abad et al, 2022a;Abad et al, 2022b). As observed in Figure 1E, there is a reduction in valley angle, promoting the birthplace of the Frontiers in Environmental Science frontiersin.org Amazon River as the confluence of the Marañon and Ucayali Rivers (Garcia et al, 2022;Guerrero et al, 2022).…”

Section: Study Areamentioning

confidence: 99%

“…This study covered satellite imagery processing every 5 years between 1985 and 2021 (the last time interval was 6 years from 2015 to 2021) due to the dynamism of meandering (Ucayali and Huallaga) and anabranching (Marañon) rivers (Salo et al, 1986;Frias et al, 2015;Abad et al, 2022a), reporting a total of 36 years of analysis. Landsat imagery was downloaded from the USGS Earth Explorer data portal (https://earthexplorer.usgs.gov/) considering a cloud percentage of less than 10% during the dry season in the area-from July to December.…”

Section: Modern River Dynamicsmentioning

confidence: 99%

“…The anabranching structures have low migration rates compared to meandering channels (see Figure 3F), thus the confluence location of the Marañon and Ucayali Rivers (birthplace of the Amazon River) is dominated by the planform Frontiers in Environmental Science frontiersin.org dynamics of the meandering Ucayali River (Garcia et al, 2022;Guerrero et al, 2022). Abad et al (2022a) described that bends along the lower Ucayali River transition from purely meandering to anabranching rivers, observing islands and multichannel structures. Figure 3K shows the planform dynamics of bends along the Ucayali River in the region where the Ucayali and Puinahua rivers share water flow.…”

Section: Modern and Ancient River Dynamicsmentioning

confidence: 99%

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Free and underfit-scavenger river dynamics dominate the large Amazonian Pacaya-Samiria wetland structure

Rojas

Abad²,

Roque³

et al. 2023

Front. Environ. Sci.

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The Peruvian Amazon is known for harboring the greatest biodiversity on the planet, with a world record for biodiversity per unit area. Previous studies suggested that the high ecological value depends on correlations between ecosystem functionality and seasonal inundation control vegetation patches. However, the knowledge on how river morphodynamics and its complex erosion-depositional processes influence the aquatic mosaic and fishing activity in the region is still incipient. This study examines the hydrogeomorphology of the Peruvian tropical wetland of Pacaya Samiria, located in Western Amazonia, and its role in the distribution of aquatic habitats. By using remote sensing techniques, the hydrogeomorphological connectivity that bounds the Pacaya Samiria National Reserve is characterized by ancient to modern river processes. Additionally, river signatures developed by the Ucayali, Marañon, Huallaga, Pacaya, and Samiria Rivers overlap with fish extraction and dominant vegetation to describe how geomorphology is associated with the spatial distribution of fishing zones. Results indicated that paleochannels regulate wetland drainage within the Ucamara Depression, supporting stational water stagnation, vegetation cover, and formation of carbon rich detritus, relevant aspects to understand fish traits. Moreover, the Ucayali River dominates river dynamics in the Pacaya Samiria wetland, thus playing a pivotal role in shaping the complexity of streams and lakes. Furthermore, underfit-scavenger meandering rivers are observed in areas where paleochannels from large rivers are found. A geomorphological characterization of drainage patterns in freshwater environments, such as Amazonian wetlands, is crucial to develop sound management strategies. This methodological approach is expected to support decision-making in conservation actions in Amazonian environments based on understanding wetland connectivity and hydrogeomorphological behavior and their influence on commercial fisheries.

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Section: Modern River Dynamicsmentioning

confidence: 88%

Section: Modern and Ancient River Dynamicsmentioning

confidence: 97%

Section: Study Areamentioning

confidence: 99%

Section: Modern River Dynamicsmentioning

confidence: 99%

Section: Modern and Ancient River Dynamicsmentioning

confidence: 99%

See 3 more Smart Citations

Free and underfit-scavenger river dynamics dominate the large Amazonian Pacaya-Samiria wetland structure

Rojas

Abad²,

Roque³

et al. 2023

Front. Environ. Sci.

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Hydrogeomorphology of the origin of the Amazon River, the confluence between the Marañón and Ucayali rivers

Guerrero,

Abad,

Ortals

et al. 2024

Earth Surf Processes Landf

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The origin of the Amazon River is formed at the confluence of the Marañón and Ucayali rivers. Remote sensing and detailed hydrodynamics, sediment transport and bed morphology analysis under different hydrological conditions have been applied to understand the control mechanisms of the modern confluence, thus informing about ancient confluences. Results showed that: 1) meandering‐meandering confluences existed when bifurcated meandering channels from the Marañón River joined the meandering Ucayali River, 2) far‐field scale provided the boundary conditions for the near‐field scale processes. In the case of the Marañón River, the spatial frequency and displacement of incoming anabranching structures to the confluence location set the boundary conditions for the near‐field scale. In the case of the Ucayali River, the incoming hydrodynamics and bed morphology are governed by far‐field processes such as the occurrence of cutoffs, 3) high intensity secondary flows at large rivers were observed at far‐ and near‐field scales, where previous studies have reported that secondary flows are weak or nonexistence or mainly found downstream of confluences. Finally, 4) even though the Marañón River is larger compared with the Ucayali River, the confluence hydrogeomorphology is governed by the Ucayali River because of more developed and stronger secondary flows.

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Morphodynamics of anabranching structures in the Peruvian Amazon River

Abad,

Garcia,

Marín‐Díaz

et al. 2024

Earth Surf Processes Landf

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Along its 650‐km reach, the Peruvian Amazon River comprises anabranching structures, spanning from the confluence of the Marañón and Ucayali Rivers to the Peru–Brazil–Colombia border. Combining remote sensing techniques and field measurements, this research aims to understand the hydrogeomorphology of these anabranching structures. The multitemporal analysis every 5 years over 35 years (1985–2020) reports channel migration rates, erosion/deposition rates, angles of bifurcations and confluences, among other metrics including the number of channels, length, wavelength average, width and sinuosity, as well as the area, shape and number of islands for each structure. Fieldwork also included hydrodynamic measurements along the Peruvian Amazon River to characterize the flow structure and water fluxes. Results showed that the Peruvian Amazon River developed single (stable) and compound (unstable) anabranching structures at a spatial periodicity of about 22.4 km, with an average displacement speed of approximately 74 m/year. Compound anabranching structures were found at the inlet region (near the origin of the Amazon River) and where significant tributaries flow into the main river and water and sediment fluxes impose destabilizing boundary conditions.

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Planform Dynamics and Cut-Off Processes in the Lower Ucayali River, Peruvian Amazon

Cited by 7 publications

References 32 publications

Free and underfit-scavenger river dynamics dominate the large Amazonian Pacaya-Samiria wetland structure

Free and underfit-scavenger river dynamics dominate the large Amazonian Pacaya-Samiria wetland structure

Hydrogeomorphology of the origin of the Amazon River, the confluence between the Marañón and Ucayali rivers

Morphodynamics of anabranching structures in the Peruvian Amazon River

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