气候变化领域集成服务门户(CCPortal): Modeling long-term delta dynamics reveals persistent geometric river avulsion locations

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DOI	10.1016/j.epsl.2021.116786
	Modeling long-term delta dynamics reveals persistent geometric river avulsion locations
	Ratliff K.M.; Hutton E.W.H.; Murray A.B.
发表日期	2021
ISSN	0012821X
卷号	559
英文摘要	River deltas grow through repeated stacking of sedimentary lobes, the location and size of which are determined by channel avulsions (relatively sudden changes in river course). We use a model coupling fluvial and coastal processes to explore avulsion dynamics under a range of wave energies and sea-level-rise rates and find that the primary control on avulsion location and delta lobe size in our model is the critical superelevation ratio (SER), the amount of channel aggradation relative to the surrounding floodplain that is required to trigger an avulsion. The preferred avulsion location arises because of geometric constraints – a preferential avulsion node occurs at the break in floodplain slope that develops as the river progrades and/or sea level rises. This concavity develops in our model because the river profile aggrades and erodes via linear diffusion, whereas the diffusion of the floodplain topography is limited to episodic crevasse splays. These results are in contrast to recent modeling work, which was motivated by laboratory experiments and assumes a union between river channel and floodplain aggradation rates, and where avulsion nodes are driven by backwater hydrodynamics. The preferred avulsion length in our model scales well with laboratory, field, and model results without including hydrodynamic backwater effects. This work suggests an alternative mechanism to explain avulsion locations on deltas where floodplain topography aggrades and/or diffuses more slowly than the river channel profile, and it points to the need to elucidate river channel and floodplain connectivity over large space and time scales, and how the connectivity varies from one type of delta to another. © 2021
关键词	avulsion node delta morphodynamics river avulsion river delta
英文关键词	Banks (bodies of water); Floods; Hydrodynamics; Location; Sea level; Topography; Water; Backwater effects; Channel avulsions; Coastal process; Geometric constraint; Laboratory experiments; Linear diffusion; Primary control; Sedimentary lobes; Rivers
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203261
作者单位	Division of Earth & Ocean Sciences, Nicholas School of the Environment, Duke University, Box 90230, Durham, NC 27708-0230, United States; Community Surface Dynamics Modeling System, University of Colorado, Campus Box 450, Boulder, CO 80309-0450, United States
推荐引用方式 GB/T 7714	Ratliff K.M.,Hutton E.W.H.,Murray A.B.. Modeling long-term delta dynamics reveals persistent geometric river avulsion locations[J],2021,559.
APA	Ratliff K.M.,Hutton E.W.H.,&Murray A.B..(2021).Modeling long-term delta dynamics reveals persistent geometric river avulsion locations.Earth and Planetary Science Letters,559.
MLA	Ratliff K.M.,et al."Modeling long-term delta dynamics reveals persistent geometric river avulsion locations".Earth and Planetary Science Letters 559(2021).