Sediment accumulation in embayments controlled by bathymetric slope and wave energy: implications for beach formation and persistence

Preston, J., Hurst, M. D. , Mudd, S. M., Goodwin, G. C.H., Newton, A. J. and Dugmore, A. J. (2018) Sediment accumulation in embayments controlled by bathymetric slope and wave energy: implications for beach formation and persistence. Earth Surface Processes and Landforms, 43(11), pp. 2421-2434. (doi: 10.1002/esp.4405)

Abstract

High energy, rocky coastlines often feature sandy beaches within headland‐bound embayments. Not all such embayments have beaches however, and beaches in embayments can be removed by storms and may subsequently reform. What dictates the presence or absence of an embayed beach and its resilience to storms? In this paper, we explore the effect of offshore slope and wind conditions on nearshore sediment transport within idealised embayments to give insight into nearshore sediment supplies. We use numerical simulations to show that sand can accumulate near shore if the offshore slope is >0.025 m/m, but only under persistent calm conditions. Our modelling also suggests that if sediment in an embayment with an offshore gradient steeper than 0.025 m/m is removed during a period of persistent stormy conditions, it will be unlikely to return in sub‐decadal timescales. In contrast, sediment located in embayments with shallower gradients can reform swiftly in both calm and stormy conditions. Our findings have wide implications for contemporary coastal engineering in the face of future global climate change, but also for Quaternary environmental reconstruction. Our simple method to predict beach stability based on slope can be used to interpret differing responses of embayments to periods of changing coastal storminess such as the medieval climate anomaly‐little ice age (MCA‐LIA) transition.

• Item Type: Articles
• Additional Information: This work was supported in part by the Deutsche Forschungsgemeinschaft under grant number CA 146/17-1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hurst, Dr Martin
• Authors: Preston, J., Hurst, M. D., Mudd, S. M., Goodwin, G. C.H., Newton, A. J., and Dugmore, A. J.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Earth Surface Processes and Landforms
• Publisher: Wiley
• ISSN: 0197-9337
• ISSN (Online): 1096-9837
• Published Online: 22 May 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in Earth Surface Processes and Landforms 43(11):2421-2434
• Publisher Policy: Reproduced under a Creative Commons License