Crevasse splay morphodynamics near a non-vegetated, ephemeral river terminus: Insights from process-based modelling

Li, Jiaguang; Vegt, Helena van der; Storms, J.E.A.; Tooth, Stephen

doi:10.1016/j.jhydrol.2023.129088

Cited by 4 publications

(4 citation statements)

References 63 publications

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“…Therefore, any crevasse channels that formed during the rising limb of the hydrograph (as flows overtopped channel banks) would be reworked by sheet flows over the entire flood basin. Furthermore, Li et al (2023) demonstrated that crevasse splays are shortened and single crevasse channels less pronounced when floodplains are submerged, which also supports the hypothesis of sheetflow suppressing crevasse channel development. No laterally filled crevasse channels were observed (as are common in the Rı ´o Colorado; Donselaar et al, 2013), suggesting that, if present, they were likely not abundant or well-developed by the peak of flooding events since no remnants are visible.…”

Section: Floodplainssupporting

confidence: 74%

A depositional model for meandering rivers without land plants

et al. 2023

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The recognition of meandering rivers in Earth's prevegetation stratigraphic record is hindered by an absence of depositional models specifically tailored to unvegetated single‐channel rivers. As a result, their abundance on the early Earth is currently unknown. Here, sedimentological studies of two modern meandering river reaches with unvegetated banks were conducted. Both reaches are located in arid basins of Nevada, USA. Stratigraphy was analysed in conjunction with satellite imagery and high‐resolution topographic data to understand how channels and floodplains record past flow conditions. Analyses of point‐bar and channel‐fill deposits showed that lateral accretion sets are not heterolithic but, rather, composed of mixed sand and sand‐sized mud aggregates (clumps of clay and silt) interpreted to have formed through flocculation. Levées are present but subdued. Notably, downstream‐migrating outer‐bank‐attached bars are prominent architectural features that may be common in unvegetated meandering rivers in arid landscapes elsewhere. The identification of such depositional elements in the stratigraphic record may enhance recognition of ancient unvegetated meandering rivers and improve reconstructions of palaeohydrology on early Earth and Mars.

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Section: Floodplainssupporting

confidence: 74%

A depositional model for meandering rivers without land plants

et al. 2023

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“…Delft3D has been widely used. For instance, Geng et al [39] used Delft3D to simulate the spatial distribution of sediment particle size; Li et al [40] used Delft3D to conduct a process-based modeling study to separate the effects of hydrological control on fracture morphology dynamics; and Lei et al [41] applied the Delft3D model with PM to Shenzhen Bay, China, to verify the effectiveness of PM.…”

Section: Numerical Modelsmentioning

confidence: 99%

Predicting the Flow Fields in Meandering Rivers with a Deep Super-Resolution Convolutional Neural Network

Yan,

Du,

Zhang

et al. 2024

Water

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The hydrodynamic model, based on the strict conservation of momentum and continuity equations, can accurately simulate the distribution of a flow field. However, significant computing time and storage space requirements limit real-time prediction. Machine learning is well known for its fast computing speed and powerful learning ability, but its accuracy depends on an abundance of training data, hindering its wider use in locations without sufficient measurements. Application restrictions in data-deficient areas can be addressed through transfer learning, provided that two areas share common characteristics. In this study, a machine learning method based on a deep super-resolution convolutional neural network (DSRCNN) and transfer learning is proposed, validated, and applied to model two bend flows and one realistic test case. Firstly, the hydrodynamic model was established and validated against measured data. The validated model was considered to have the ability to generate real data and was used to generate a comprehensive data set for training and validating the machine learning model. Three different methods were compared and tested, with Realizable k-ε performing better than the others in predicting the outer bank flow distribution. DSRCNN was compared to a plain SRCNN (PSRCNN), as well as Bilinear, Nearest, and Bicubic methods, and the results showed that DSRCNN had the best performance. We compared Raw, RT, and TL methods, finding that the TL method performed the best overall. Therefore, the research results showed that the developed super-resolution convolutional neural network can provide more reliable predications and serve as an ideal tool for simulating flow field distribution in bends.

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“…Some earlier studies conducted flume experiments of flooding flows that involved a sediment supply to understand the geomorphic features of the resultant deposits, but the formative processes of the crevasse-splay deposits were not described (e.g., Takahashi et al 1984;Fujita et al 1987;Takahashi and Nakagawa 1987;Tobita et al 2015). Numerical modelings of the deposition involving a levee breach have also been conducted (e.g., Takahashi and Nakagawa 1989;Yuill et al 2016;Millard et al 2017;Nienhuis et al 2018;Li et al 2023). For example, Millard et al (2017) examined how channel-sediment size and flood-basin hydrology influence sediment transportation to the floodplain through crevasse splays.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Millard et al (2017) examined how channel-sediment size and flood-basin hydrology influence sediment transportation to the floodplain through crevasse splays. Li et al (2023) reported that increases in discharge lead to more rapid splay sedimentation, and increases in floodplain water level result in shorter but wider splays. Yuill et al (2016) demonstrated an erosional and depositional process during a levee breach using a coupled field observation and numerical modeling of crevasse-splay deposits at West Bay, Lousiana, USA.…”

Section: Introductionmentioning

confidence: 99%

Flume experiments in the development of crevasse-splay deposits: transition from asymmetric to symmetric geometry

Kato,

Yamada,

Naruse

et al. 2023

Journal of Sedimentary Research

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Crevasse-splay deposits play an important role in the reconstruction of the magnitude of past flood events and in understanding the behavior of river systems. Despite the extensive studies conducted on the geometry and facies of crevasse-splay deposits, their spatiotemporal developmental processes have remained insufficiently understood. In this study, scaled flume experiments were conducted to study the relationship between the developmental processes of crevasse splays and their characteristics. An experimental flume was set up in a tank to simulate the 2019 Chikuma River flood, Central Japan event. To model the overbank flow, an opening was created on the side of the flume’s wall through which the flow flooded onto a horizontal acrylic plate. The sediment used in the experiments consisted of particles with grain sizes of approximately 0.3 and 0.1 mm, which were determined to be equivalent to bedload gravel and suspended sand in a real-scale river using dimensional analysis. The results of the experi ments revealed three important findings: (1) Crevasse-splay deposits initially developed an asymmetric shape extending downstream of the main river channel but gradually showed a symmetric geometry. The river mainstream initially influenced the direction of the inundation flow, but channel bifurcations after the deposition of the sediment piles later changed the geometry of splays into a more symmetric shape. (2) Crevasse-splay deposits developed in two distinct regions (proximal and distal splay), corresponding to sediment transport by bedload and suspended load, respectively. These two regions are commonly observed in the actual field scale. (3) The original overbank flow was a sheet flow without channels, which caused coarse-grained sediments to be spread over a wide area. Subsequently, the accumulation of coarse sands in the developed channel interiors resulted in the buildup of finer-grained sediments upstream of the proximal splay. Thus, the proximal splay deposits became slightly coarse downstream, whereas they rapidly became fine at the boundary with the distal splay. These findings indicate that the characteristics of crevasse-splay deposits vary with the landform’s development stage, thus providing a basis for interpreting their depositional facies.

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Crevasse splay morphodynamics near a non-vegetated, ephemeral river terminus: Insights from process-based modelling

Cited by 4 publications

References 63 publications

A depositional model for meandering rivers without land plants

A depositional model for meandering rivers without land plants

Predicting the Flow Fields in Meandering Rivers with a Deep Super-Resolution Convolutional Neural Network

Flume experiments in the development of crevasse-splay deposits: transition from asymmetric to symmetric geometry

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