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Preprints
https://doi.org/10.5194/egusphere-2022-267
https://doi.org/10.5194/egusphere-2022-267
12 May 2022
 | 12 May 2022

Episodic sediment supply to alluvial fans: implications for fan incision and morphometry

Anya Sophia Leenman and Brett Curtis Eaton

Abstract. Sediment supply is widely believed to be a key control on alluvial fan morphology and channel dynamics. Although the sediment supply to natural fans is rather episodic, experimental studies of alluvial fans often use constant sediment supply rates, making it difficult to relate fan dynamics to the magnitude and frequency of sediment supply in the field. This paper presents a series of experiments designed to test the impact of episodic sediment supply on fan evolution and dynamics. We compare four experiments, each with the same mean sediment supply but different durations of high- and low-supply periods. The experiments show that fan morphology and channel dynamics respond systematically to the temporal elongation of sediment supply oscillations: longer supply cycles generate flatter fans with more trenched channels. These results highlight how different basin conditions might generate different fan morphologies: supply limited basins with intermittent sediment supply might generate fans that are flatter than expected. Our results raise the question of whether a constant sediment supply in experimental models can adequately characterise the dynamics of natural fans in the field.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Journal article(s) based on this preprint

09 Nov 2022
Episodic sediment supply to alluvial fans: implications for fan incision and morphometry
Anya S. Leenman and Brett C. Eaton
Earth Surf. Dynam., 10, 1097–1114, https://doi.org/10.5194/esurf-10-1097-2022,https://doi.org/10.5194/esurf-10-1097-2022, 2022
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

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The supply of sediment (sand and gravel) carried by a stream out of a steep mountain valley is...
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