TY - JOUR
T1 - Aeolian sand transport and deposition patterns within a large woody debris matrix fronting a foredune
AU - Grilliot, Michael J.
AU - Walker, Ian
AU - Bauer, Bernard O.
N1 - Funding Information:
This research was conducted in partnership with the Hakai Institute as part of a Coastal Sand Ecosystems research program and was supported financially and logistically by partners at the Hakai Institute and Tula Foundation , notably Eric Peterson and Christina Munck. This project was also funded by a Hakai Ph.D. Fellowship to Michael J. Grilliot, Canadian Natural Sciences and Engineering Research Council ( NSERC ) Discovery grant (no. 239751-2011) and Canada Foundation for Innovation (CFI) Leader's Opportunity Fund (projects #4632 and #29502) to Ian J. Walker. Field assistance was provided by staff from the Hakai Institute and other students from UVic, including Derek Heathfield, Alana Rader, and Felipe Gomez. The authors recognize that this study took place on the traditional territory of the Heiltsuk and Wuikinuxv First Nations, and are grateful for the opportunity. The authors would like to thank the anonymous reviewers whose comments helped improve the manuscript.
Funding Information:
M.J.G., I.J.W., and B.O.B. conceived, designed, and performed the experiments; M.J.G. analyzed the data with guidance from I.J.W. and B.O.B.; I.J.W. and B.O.B. contributed equipment and analysis tools; M.J.G. wrote the first draft of the paper with thematic guidance and editorial assistance from I.J.W. and B.O.B. The Hakai Coastal Sand Ecosystems Program funding was secured by IJW and all site logistics were supported by the Hakai Institute.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - Sediment transport pathways and resulting erosion-deposition patterns across beach-foredune systems can be complex. Although a great deal is known about the effects of wind fetch, surface moisture, topographic forcing, and vegetation cover, the role of large woody debris (LWD) as a control on sediment redistribution across beaches is relatively understudied. Pieces of LWD act as non-porous roughness elements that induce secondary flow circulation, thereby creating unique sedimentation patterns that differ markedly from those over a flat beach. Large accumulations of LWD collectively have a bulk porosity that provides substantial sand trapping volume, yet, no studies to date have quantified the effect of LWD on aeolian sand transport. Results from a field study on a macrotidal beach on Calvert Island, British Columbia, Canada, show that the LWD matrix alters the character of the turbulent boundary layer in a way that reduces sediment flux by 99%. Sand is trapped within the LWD matrix, thereby interrupting sediment delivery from the nearshore to the foredune. As such, LWD has the potential to modulate rates of foredune recovery, growth, and evolution. The relative importance of this effect depends on the density and arrangement of LWD as a fundamental control on aeolian sediment transport, as well as on the magnitude and frequency of events that erode the beach periodically and re-organize the LWD matrix.
AB - Sediment transport pathways and resulting erosion-deposition patterns across beach-foredune systems can be complex. Although a great deal is known about the effects of wind fetch, surface moisture, topographic forcing, and vegetation cover, the role of large woody debris (LWD) as a control on sediment redistribution across beaches is relatively understudied. Pieces of LWD act as non-porous roughness elements that induce secondary flow circulation, thereby creating unique sedimentation patterns that differ markedly from those over a flat beach. Large accumulations of LWD collectively have a bulk porosity that provides substantial sand trapping volume, yet, no studies to date have quantified the effect of LWD on aeolian sand transport. Results from a field study on a macrotidal beach on Calvert Island, British Columbia, Canada, show that the LWD matrix alters the character of the turbulent boundary layer in a way that reduces sediment flux by 99%. Sand is trapped within the LWD matrix, thereby interrupting sediment delivery from the nearshore to the foredune. As such, LWD has the potential to modulate rates of foredune recovery, growth, and evolution. The relative importance of this effect depends on the density and arrangement of LWD as a fundamental control on aeolian sediment transport, as well as on the magnitude and frequency of events that erode the beach periodically and re-organize the LWD matrix.
KW - Beach-dune systems
KW - Coastal erosion
KW - Roughness elements
KW - Sediment transport
UR - http://www.scopus.com/inward/record.url?scp=85064677208&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85064677208&partnerID=8YFLogxK
U2 - 10.1016/j.geomorph.2019.04.010
DO - 10.1016/j.geomorph.2019.04.010
M3 - Article
AN - SCOPUS:85064677208
VL - 338
SP - 1
EP - 15
JO - Geomorphology
JF - Geomorphology
SN - 0169-555X
ER -