Date of Award

Spring 2021

Document Type

Open Access Thesis

Department

Geography

First Advisor

Jean Taylor Ellis

Abstract

Sediment deposition impacts dune morphology and is a product of many environmental factors. Dune vegetation is related to post-storm dune recovery and morphology. Though it is widely agreed that vegetation impacts sediment deposition, this relationship has not yet been quantified in the field. This research was conducted at Isle of Palms, a meso-tidal barrier island in South Carolina, where we collected topographic and vegetation data over an incipient foredune. Vegetation data were classified by functional type (dune-builder or dune-stabilizer) or land cover (sand, wrack). We identified land cover changes resulting in greater surface roughness. To relate land cover change to morphologic change, we established the Aeolian Depositional Lag Time (ADLT) parameter, which is the average time between land cover change onset and first observed deposition. The average ADLT for all observations was 8.3 weeks. We analyze the rates of topographic change within each land cover type and analyze the distribution of land cover change and cumulative morphologic change over one year. Results suggest dune-builders and dune-stabilizers have different depositional impacts, likely due to differences in surface roughness and habitat preferences. The average topographic rate of change for all observations in this study was 1.1 cm/ADLT period. We present a conceptual model for seaward expansion of vegetation in an incipient foredune, considering varying surface roughness of vegetation types. As land cover changes, deposition rates vary based on vegetation type and associated surface roughness. Deposition rates slow as vegetation matures; surface roughness increases are dependent on plant growth. The varying surface roughness lengths associated with different functional types impact aeolian deposition.

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Geography Commons

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