Abstract
The understanding of the complicated braiding mechanisms in braided rivers is closely related to avulsions. They control the channel generation, migration and disappearance in large lowland braided rivers, and are considered to be the key factor that keeps the river maintaining a dynamic braided pattern. However, their occurring processes and mechanisms are still not well understood due to the lack of detailed measurements with sufficient temporal and spatial data covering multiple bifurcations. In the present study, a numerical model based on the physical process of hydrodynamics and sediment transport is used to simulate the suspended sediment transport and river channel evolution in braided rivers. The model predicted braiding processes are comparable to those observed in nature. Efforts are made to investigate the morphological processes that are key for river braiding. Three types of avulsions observed in natural rivers have been identified in the model predicted river and their evolution processes and controlling factors are examined based on the predicted flow velocity, sediment concentration, bed elevation and sediment size distribution. It was found that, a curving channel bend is the key factor in introducing a constriction avulsion, while the choking avulsion and apex avulsion are controlled by the water surface slope and bed elevation. They are mostly affected by the upstream channel pattern changes.
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References
Ashmore PE (1993) Anabranch confluence kinetics and sedimentation processes in gravel-braided streams. In: Best JL, Bristow CS (eds) Braided rivers. Geological Society, London, pp 129–146
Ashworth PJ, Best JL, Roden JE, Bristow CS, Klaassen GJ (2000) Morphological evolution and dynamics of a large, sand braid-bar. Jamuna River, Bangladesh. Sedimentology 47:533–555
Bridge JS (1993) The interaction between channel geometry, water flow, sediment transport and deposition in braided rivers. In: Best JL, Bristow CS (eds) Braided rivers. Geological Society, London, pp 13–71
Ferguson RI (1993). Understanding braiding processes in gravel-bed rivers: progress and unsolved problems. In: Braided rivers, Best JL, Bristow CS (eds) Geological Society, London, pp: 73–87
Ferguson RI, Ashmore PE, Ashworth PJ, Paola C, Prestegaard KL (1992) Measurements in a Braided River chute and lobe: 1. Flow pattern, sediment transport, and channel change. Water Resour Res 28:1877–1886
Field J (2001) Channel avulsion on alluvial fans in southern Arizona. Geomorphology 37:93–104
Jang CL, Shimizu Y (2005a) Numerical simulations of the behavior of alternate bars with different bank strengths. J Hydraul Res 43:596–612
Jang CL, Shimizu Y (2005b) Numerical simulation of relatively wide, shallow channels with erodible banks. J Hydraul Eng 131:565–575
Kleinhans MG (2010) Sorting out river channel patterns. Prog Phys Geogr 34:287–326
Kleinhans MG, Hardy RJ (2013) River bifurcations and avulsion. Earth Surf Process Landf 38:317–318. https://doi.org/10.1002/esp.3354
Lin BL, Falconer RA (1997) Tidal flow and transport modeling using ultimate quickest scheme. J Hydraul Eng 123:303–314
Lin BL, Falconer RA (2006) Hydrological and environmental modeling of transport processes in rivers and estuaries. Encycl Hydrol Sci 1:271–284
Mumpy AJ, Jol HM, Kean WF, Isbell JL (2007) Architecture and sedimentology of an active braid bar in the Wisconsin River based on 3-D ground penetrating radar. Geol Soc Am Spec Pap 432:111–131
Nicholas AP (2013) Modelling the continuum of river channel patterns. Earth Surf Process Landf 38:1187–1196
Pittaluga MB, Repetto R, Tubino M (2003) Channel bifurcation in braided rivers: equilibrium configurations and stability. Water Resour Res 39:1046
Sarma JN (2005) Fluvial process and morphology of the Brahmaputra River in Assam, India. Geomorphology 70:226–256
Schuurman F, Kleinhans MG (2015) Bar dynamics and bifurcation evolution in a modelled braided sand-bed river. Earth Surface Processes and Landforms
Schuurman F, Marra WA, Kleinhans MG (2013) Physics-based modeling of large braided sand-bed rivers: bar pattern formation, dynamics, and sensitivity. J Geophys Res Earth Surf 118:2509–2527
Slingerland R, Smith ND (2004) River avulsions and their deposits. Annu Rev Earth Planet Sci 32:257–285
van Rijn LC (1984) Sediment transport, part II: suspended load transport. J Hydraul Eng 110:1613–1641
Wei Z (1993) A one dimensional sediment model for the Yellow River, Report of Wuhan University of Hydro-electrical Power (in Chinese)
Wu W (2007) Computational river dynamics. Taylor & Francis Group, London, p 499
Xu J (2002) Implication of relationships among suspended sediment size, water discharge and suspended sediment concentration: the Yellow River basin, China. Catena 49:289–307
Yang H (2013) Development of a physics-based morphodynamic model and its application to braided rivers. PhD thesis. Cardiff University, pp: 235
Yang H, Lin B, Zhou J (2015) Physics-based numerical modelling of large braided rivers dominated by suspended sediment. Hydrol Process 29:1925–1941
Yang H, Lin B, Sun J, Huang G (2017) Simulating laboratory braided rivers with bed-load sediment transport. Water 9. https://doi.org/10.3390/w9090686
Zhao Y, Zhou W, Fei X, Hu C, Shen G, Chen J (1998) Principles of channel evolution in the lower Yellow River. Yellow River Water Conservancy Press, Zhengzhou, p 130 (in Chinese)
Zhou J, Lin B (2006) Flow and sediment modelling. China Hydropower Press, Beijing, pp 173–278 (in Chinese)
Zhou J, Lin B, Lin B (2003) Rational basis for suspended sediment modeling. Int J Sediment Res 18:177–195
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We are grateful for the financial support from National Key R&D Program of China (grant No. 2016YFC0502204) and South China Agricultural University (grant No. 7600-217244).
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Yang, H., Lin, B. & Zhou, J. Avulsions in a Simulated Large Lowland Braided River. Water Resour Manage 32, 2301–2314 (2018). https://doi.org/10.1007/s11269-018-1930-8
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DOI: https://doi.org/10.1007/s11269-018-1930-8