Sandy shoreline recovery ability after breakwater removal

Frontiers in Marine Science

Marine Science

Jinhai Zheng¹  Chi Zhang²  Shanhang Chi² 

[1] College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing, China;Key Laboratory of Ministry of Education for Coastal Disaster and Protection, Hohai University, Nanjing, China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China;College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing, China;

关键词: shoreline evolution;    recovery ability;    structure removal;    numerical model;    coastal resilience;   

DOI  :  10.3389/fmars.2023.1191386

 received in 2023-03-23, accepted in 2023-05-04,  发布年份 2023

来源: Frontiers

【 摘 要 】

The removal of coastal structures has emerged as an increasingly considered alternative nature-based solution to sandy coastal erosion due to unsuited structure construction. However, its effectiveness remains uncertain because the ability of natural beach recovery is unclear due to little understanding of shoreline response to the structure removal. In this study, we use a recently developed numerical model to explore the sandy shoreline recovery ability after the removal of an attached breakwater. Both recovery duration and recovery ratio are analyzed concerning various breakwater configurations and environmental settings in a simplified and generalized framework. We find that the sandy shoreline has the ability to naturally recover after breakwater removal but with different recovery durations (years to centuries) and recovery ratios (full to partial). A higher shoreline recovery ability (i.e., shorter duration and larger ratio) is related to shorter effective breakwater length, downdrift inclined breakwater direction, lower angle of wave incidence, and greater longshore sediment transport rate. We reveal that the behavior of sand spit evolution, including the extension and split of the sand spit, is the dominant mechanism for distinct shoreline recovery processes. Two simple formulas are finally proposed to preliminarily estimate shoreline recovery ability for practical purposes. The results of the present study provide new insights into coastal morphological resilience to engineering interventions.

【 授权许可】

Unknown   
Copyright © 2023 Chi, Zhang and Zheng