Characterizing braided rivers in two nested watersheds in the Source Region of the Yangtze River on the Qinghai-Tibet Plateau

Li, Zhiwei; Lu, Haiyang; Gao, Peng; You, Yuqi; Hu, Xuyue

doi:10.1016/j.geomorph.2019.106945

Cited by 20 publications

(22 citation statements)

References 94 publications

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“…However, what distinguishes anabranching from braided systems is the impact of vegetation on islands and the associated persistence of multithread patterns at the bankfull stage (Burge, 2006;Han & Brierley, 2020;Henriques et al, 2021;Jansen & Nanson, 2010;Tal & Paola, 2010). Compared to typical braided reaches in the Qinghai-Tibet Plateau, such as the upper Lancang and Yangtze Rivers (Gao et al, 2022;Li et al, 2020), the MAS exhibited discernably denser vegetation on islands (Figure 1c). This is possibly attributable to the extensive growth of Salix atopantha, a willow shrub endemic to the Qinghai-Tibet Plateau, within the anabranching system, which significantly promotes the stability of fine sediments and has transformed mobile bars into more stable islands.…”

Section: Implications For the Channel-pattern Continuum Of Multithrea...mentioning

confidence: 99%

Morphodynamic Characteristics of a Complex Anabranching System in the Qinghai‐Tibet Plateau and the Implications for Anabranching Stability

Guo

Gao

2023

JGR Earth Surface

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The understanding of fluvial processes controlling morphological adjustments and stability of anabranching rivers remains incomplete. Focusing on a complex anabranching system in the Upper Yellow River, this study quantifies the morphological characteristics and lateral dynamics of islands and channels in four reaches over a 56‐km river course from 1986 to 2017. Using five heuristic anabranching structures derived from the studied anabranching system, we estimate sediment transport capacities and assess their implications for the morphodynamics of anabranching rivers. These results show that the system exhibited a highly complex pattern featuring high channel multiplicity and dominance of islands. Over the study periods, the system exhibited an accreting disequilibrium state, which was highlighted by spatiotemporally diverse and dynamic patterns of islands. Morphological changes in islands were dominated by expansion and shrinkage, which caused more areal changes than other modes of change, including coalescence, cleavage, new island formation, and elimination. These processes controlled the creation and elimination of small anabranches, whereas the size and morphology of large channels remained comparatively stable, which maintained the stability of this anabranching pattern. The stability of the anabranching pattern is further supported by estimations of transport capacity in that the main channels transport most sediments and in that excess development of small anabranches promotes sediment deposition within the system. Overall, this study provides new insight into the morphodynamic properties of anabranching rivers, demonstrating that, instead of channel numbers, island dynamics and interactions with channels are controls of the evolutionary processes and stability of anabranching rivers.

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Section: Implications For the Channel-pattern Continuum Of Multithrea...mentioning

confidence: 99%

Morphodynamic Characteristics of a Complex Anabranching System in the Qinghai‐Tibet Plateau and the Implications for Anabranching Stability

Guo

Gao

2023

JGR Earth Surface

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“…It has an average elevation of 4,500 m above sea level with an average gradient of ~3.9‰ (Yu et al, 2014). The channel pattern is characterized by the braided river (Li et al, 2019). In the TTH, the area of glaciers is 382 km 2 (glacier coverage is ~2%).…”

Section: Study Areamentioning

confidence: 99%

Substantial Increases in the Water and Sediment Fluxes in the Headwater Region of the Tibetan Plateau in Response to Global Warming

Zhou³

et al. 2020

Geophysical Research Letters

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The long‐term effects of increased temperatures on sediment fluxes in cold regions remain poorly investigated. Here, we examined the multidecadal changes in runoff and sediment fluxes in the Tuotuohe River, a headwater river of the Yangtze River on the Tibetan Plateau (TP). The sediment fluxes and runoff increased at rates of 0.03 ± 0.01 Mt/yr (5.9 ± 1.9%/yr) and 0.025 ± 0.007 × km3/yr (3.5 ± 1.0%/yr) from 1985 to 2016, with net increases of 135% and 78% from 1985–1997 to 1998–2016, respectively. The increases are primarily due to warming temperature (+1.44°C) and intensified glacier‐snow‐permafrost melting, with enhanced precipitation (+30%) as a secondary cause. Sediment fluxes are much more susceptible to climate warming than runoff in this undisturbed cold environment. The substantially increased sediment fluxes from the headwater region could threaten the numerous constructed reservoirs and influence the aquatic ecosystems of the TP and its marginal areas.

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“…For instance, Li et al [4] interpreted Landsat remote-sensing images and figured out that the planar morphology of the local braided reaches of the Tongtian River is positively correlated with the branching intensity, which is strongly related to streamflow. Li et al [5] extracted water bodies of the two main braided rivers (the Tongtian River and Ulan Moron) located at the source of the Yangtze River using the Modified Normalized Difference Water Index (MNDWI) and found similar morphological changes in these two rivers. Li et al [6] used remote-sensing images and hydrological data from 2006 to 2017, combined with the MNDWI to extract the water body of the local braided reaches of the Tongtian River, and found that the cutting of the group sandbars in the braided channel was due to the floodplain erosion during the flooding period and the water-level difference between the secondary branches and the main branch.…”

Section: Introductionmentioning

confidence: 99%

Monitoring and Predicting Channel Morphology of the Tongtian River, Headwater of the Yangtze River Using Landsat Images and Lightweight Neural Network

et al. 2022

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The Tongtian River is the source of the Yangtze River and is a national key ecological reserve in China. Monitoring and predicting the changes and mechanisms of the Tongtian River channel morphology are beneficial to protecting the “Asian Water Tower”. This study aims to quantitatively monitor and predict the accretion and erosion area of the Tongtian River channel morphology during the past 30 years (1990–2020). Firstly, the water bodies of the Tongtian River were extracted and the accretion and erosion areas were quantified using 1108 Landsat images based on the combined method of three water-body indices and a threshold, and the surface-water dataset provided by the European Commission Joint Research Centre. Secondly, an intelligent lightweight neural-network model was constructed to predict and analyze the accretion and erosion area of the Tongtian River. Results indicate that the Tongtian River experienced apparent accretion and erosion with a total area of 98.3 and 94.9 km2, respectively, during 1990–2020. The braided (meandering) reaches at the upper (lower) Tongtian River exhibit an overall trend of accretion (erosion). The Tongtian River channel morphology was determined by the synergistic effect of sediment-transport velocity and streamflow. The lightweight neural network well-reproduced the complex nonlinear processes in the river-channel morphology with a final prediction error of 0.0048 km2 for the training session and 4.6 km2 for the test session. Results in this study provide more effective, reasonable, and scientific decision-making aids for monitoring, protecting, understanding, and mining the evolution characteristics of rivers, especially the complex change processes of braided river channels in alpine regions and developing countries.

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Characterizing braided rivers in two nested watersheds in the Source Region of the Yangtze River on the Qinghai-Tibet Plateau

Cited by 20 publications

References 94 publications

Morphodynamic Characteristics of a Complex Anabranching System in the Qinghai‐Tibet Plateau and the Implications for Anabranching Stability

Morphodynamic Characteristics of a Complex Anabranching System in the Qinghai‐Tibet Plateau and the Implications for Anabranching Stability

Substantial Increases in the Water and Sediment Fluxes in the Headwater Region of the Tibetan Plateau in Response to Global Warming

Monitoring and Predicting Channel Morphology of the Tongtian River, Headwater of the Yangtze River Using Landsat Images and Lightweight Neural Network

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