The University of Southampton
University of Southampton Institutional Repository

Correlation between shoreline change and planform curvature on wave‐dominated, sandy coasts

Correlation between shoreline change and planform curvature on wave‐dominated, sandy coasts
Correlation between shoreline change and planform curvature on wave‐dominated, sandy coasts
Low‐lying, wave‐dominated, sandy coastlines can exhibit high rates of shoreline change that may impact coastal infrastructure, habitation, recreation, and economy. Efforts to understand and quantify controls on shoreline change typically examine factors such as sea‐level rise; anthropogenic modifications; geologic substrate, nearshore bathymetry, and regional geography; and sediment grain size. The role of shoreline planform curvature, however, tends to be overlooked. Theoretical and numerical‐model considerations indicate that incident offshore waves interacting with even subtle shoreline curvature can drive gradients in net alongshore sediment flux that can cause significant erosion or accretion. However, these predictions or assumptions have not often been tested against observations, especially over large spatial and temporal scales. Here, we examined the correlation between shoreline curvature and shoreline‐change rates for spatially extended segments of the U.S. Atlantic and Gulf Coasts (~1700 km total). Where shoreline stabilization (nourishment or hard structures) does not dominate the shoreline‐change signal, we find a significant negative correlation between shoreline curvature and shoreline‐change rates (i.e. convex‐seaward curvature (promontories) is associated with shoreline erosion, and concave‐seaward curvature (embayments) with accretion) at spatial scales of 1–5 km alongshore and time scales of decades to centuries. This indicates that shoreline changes observed in these reaches can be explained in part by gradients in alongshore sediment flux acting to smooth spatial variations in shoreline curvature. Our results suggest that shoreline curvature should be included as a key variable in modelling and risk assessment of coastal change on wave‐dominated, sandy coastlines.
2169-9003
3090-3106
Lauzon, R.
889fbcd1-309d-4ee5-acb4-69a8fdf22240
Murray, A.B.
09e243d2-56a3-42a3-a438-7083075b153c
Cheng, S.
ff55652e-64de-4c56-9c5a-f59657324f9f
Liu, J.
5c955ef0-f384-45ac-a5dc-3471cb351c8d
Ells, K.D.
2798088b-aed2-4237-99da-3d4189061b9e
Lazarus, E.D.
642a3cdb-0d25-48b1-8ab8-8d1d72daca6e
Lauzon, R.
889fbcd1-309d-4ee5-acb4-69a8fdf22240
Murray, A.B.
09e243d2-56a3-42a3-a438-7083075b153c
Cheng, S.
ff55652e-64de-4c56-9c5a-f59657324f9f
Liu, J.
5c955ef0-f384-45ac-a5dc-3471cb351c8d
Ells, K.D.
2798088b-aed2-4237-99da-3d4189061b9e
Lazarus, E.D.
642a3cdb-0d25-48b1-8ab8-8d1d72daca6e

Lauzon, R., Murray, A.B., Cheng, S., Liu, J., Ells, K.D. and Lazarus, E.D. (2019) Correlation between shoreline change and planform curvature on wave‐dominated, sandy coasts. Journal of Geophysical Research: Earth Surface, 124 (12), 3090-3106. (doi:10.1029/2019JF005043).

Record type: Article

Abstract

Low‐lying, wave‐dominated, sandy coastlines can exhibit high rates of shoreline change that may impact coastal infrastructure, habitation, recreation, and economy. Efforts to understand and quantify controls on shoreline change typically examine factors such as sea‐level rise; anthropogenic modifications; geologic substrate, nearshore bathymetry, and regional geography; and sediment grain size. The role of shoreline planform curvature, however, tends to be overlooked. Theoretical and numerical‐model considerations indicate that incident offshore waves interacting with even subtle shoreline curvature can drive gradients in net alongshore sediment flux that can cause significant erosion or accretion. However, these predictions or assumptions have not often been tested against observations, especially over large spatial and temporal scales. Here, we examined the correlation between shoreline curvature and shoreline‐change rates for spatially extended segments of the U.S. Atlantic and Gulf Coasts (~1700 km total). Where shoreline stabilization (nourishment or hard structures) does not dominate the shoreline‐change signal, we find a significant negative correlation between shoreline curvature and shoreline‐change rates (i.e. convex‐seaward curvature (promontories) is associated with shoreline erosion, and concave‐seaward curvature (embayments) with accretion) at spatial scales of 1–5 km alongshore and time scales of decades to centuries. This indicates that shoreline changes observed in these reaches can be explained in part by gradients in alongshore sediment flux acting to smooth spatial variations in shoreline curvature. Our results suggest that shoreline curvature should be included as a key variable in modelling and risk assessment of coastal change on wave‐dominated, sandy coastlines.

Text
Lauzon_et_al-2019-Journal_of_Geophysical_Research__Earth_Surface - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 29 September 2019
e-pub ahead of print date: 19 October 2019
Published date: December 2019

Identifiers

Local EPrints ID: 436275
URI: http://eprints.soton.ac.uk/id/eprint/436275
ISSN: 2169-9003
PURE UUID: 5a5d70a0-adc0-405a-bc33-eb4907bb3816
ORCID for E.D. Lazarus: ORCID iD orcid.org/0000-0003-2404-9661

Catalogue record

Date deposited: 05 Dec 2019 17:30
Last modified: 07 Oct 2020 05:25

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×