TY - JOUR
T1 - The effects of storms and a transient sandy veneer on the interannual planform evolution of a low-relief coastal cliff and shore platform at Sargent Beach, Texas, USA
AU - Palermo, Rose V.
AU - Piliouras, Anastasia
AU - Swanson, Travis E.
AU - Ashton, Andrew D.
AU - Mohrig, David
N1 - Funding Information:
Financial support. This research has been supported by the National Science Foundation (grant no. 1745302).
Funding Information:
Acknowledgements. Thank you to Joel Johnson, Sean Gulick, Styze van Heteren, Sarah Grace Lott, Christopher J. Hein, Juan Felipe Paniagua-Arroyave, Simon Mudd, and three anonymous reviewers for insightful comments. Thank you to Charlie Ker-ans, Clark Wilson, and Josh Lambert for assistance with field equipment. And finally thank you to the many field assistants and group members that helped collect and process the data: Alicia Sendrowski, Tim Goudge, Hima Hassenruck-Gudipadi, Ben Cardenas, Wayne Wagner, Kelsi Ustipak, Michael Toomey, and Dylan Rasch. This material is based upon work supported by Plan II at the University of Texas and the National Science Foundation Graduate Research Fellowship under grant no. 1745302.
Publisher Copyright:
© 2021 Copernicus GmbH. All rights reserved.
PY - 2021/9/8
Y1 - 2021/9/8
N2 - Coastal cliff erosion is alongshore-variable and episodic, with retreat rates that depend upon sediment as either tools of abrasion or protective cover. However, the feedbacks between coastal cliff planform morphology, retreat rate, and sediment cover are poorly quantified. This study investigates Sargent Beach, Texas, USA, at the annual to interannual scale to explore (1) the relationship between temporal and spatial variability in cliff retreat rate, roughness, and sinuosity and (2) the response of retreat rate and roughness to changes in sand and shell hash cover of the underlying mud substrate as well as the impact of major storms using field measurements of sediment cover, erosion, and aerial images to measure shore platform morphology and retreat. A storm event in 2009 increased the planform roughness and sinuosity of the coastal cliff at Sargent Beach. Following the storm, aerial-image-derived shorelines with annual resolution show a decrease in average alongshore erosion rates from 12 to 4ĝmyr-1, coincident with a decrease in shoreline roughness and sinuosity (smoothing). Like the previous storm, a storm event in 2017 increased the planform roughness and sinuosity of the cliff. Over shorter timescales, monthly retreat of the sea cliff occurred only when the platform was sparsely covered with sediment cover on the shore platform, indicating that the tools and cover effects can significantly affect short-term erosion rates. The timescale to return to a smooth shoreline following a storm or roughening event, given a steady-state erosion rate, is approximately 24 years, with the long-term rate suggesting a maximum of ĝ1/4107 years until Sargent Beach breaches, compromising the Gulf Intracoastal Waterway (GIWW) under current conditions and assuming no future storms or intervention. The observed retreat rate varies, both spatially and temporally, with cliff face morphology, demonstrating the importance of multi-scale measurements and analysis for interpretation of coastal processes and patterns of cliff retreat.
AB - Coastal cliff erosion is alongshore-variable and episodic, with retreat rates that depend upon sediment as either tools of abrasion or protective cover. However, the feedbacks between coastal cliff planform morphology, retreat rate, and sediment cover are poorly quantified. This study investigates Sargent Beach, Texas, USA, at the annual to interannual scale to explore (1) the relationship between temporal and spatial variability in cliff retreat rate, roughness, and sinuosity and (2) the response of retreat rate and roughness to changes in sand and shell hash cover of the underlying mud substrate as well as the impact of major storms using field measurements of sediment cover, erosion, and aerial images to measure shore platform morphology and retreat. A storm event in 2009 increased the planform roughness and sinuosity of the coastal cliff at Sargent Beach. Following the storm, aerial-image-derived shorelines with annual resolution show a decrease in average alongshore erosion rates from 12 to 4ĝmyr-1, coincident with a decrease in shoreline roughness and sinuosity (smoothing). Like the previous storm, a storm event in 2017 increased the planform roughness and sinuosity of the cliff. Over shorter timescales, monthly retreat of the sea cliff occurred only when the platform was sparsely covered with sediment cover on the shore platform, indicating that the tools and cover effects can significantly affect short-term erosion rates. The timescale to return to a smooth shoreline following a storm or roughening event, given a steady-state erosion rate, is approximately 24 years, with the long-term rate suggesting a maximum of ĝ1/4107 years until Sargent Beach breaches, compromising the Gulf Intracoastal Waterway (GIWW) under current conditions and assuming no future storms or intervention. The observed retreat rate varies, both spatially and temporally, with cliff face morphology, demonstrating the importance of multi-scale measurements and analysis for interpretation of coastal processes and patterns of cliff retreat.
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U2 - 10.5194/esurf-9-1111-2021
DO - 10.5194/esurf-9-1111-2021
M3 - Article
AN - SCOPUS:85114669191
SN - 2196-6311
VL - 9
SP - 1111
EP - 1123
JO - Earth Surface Dynamics
JF - Earth Surface Dynamics
IS - 5
ER -