Preprints
https://doi.org/10.5194/esurf-2021-46
https://doi.org/10.5194/esurf-2021-46

  08 Jul 2021

08 Jul 2021

Review status: this preprint is currently under review for the journal ESurf.

The role of geological mouth islands on the morphodynamics of back-barrier tidal basins

Yizhang Wei1, Yining Chen2, Jufei Qiu3, Zeng Zhou1,4, Peng Yao1, Qin Jiang4, Zheng Gong1, Giovanni Coco5,1, Ian Townend1,6, and Changkuan Zhang1 Yizhang Wei et al.
  • 1State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
  • 2Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
  • 3East Sea Marine Environmental Investigating and Surveying Centre, State Oceanic Administration of China, Shanghai 310115, China
  • 4Jiangsu Key Laboratory of Coast Ocean Resources Development and Environment Security, Hohai University, Nanjing 210098, China
  • 5Faculty of Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
  • 6Ocean and Earth Sciences, University of Southampton, Southampton SO17 1BJ, UK

Abstract. The morphodyamics of back-barrier tidal basins have been extensively investigated by numerical modelling, but the influence of mouth islands (which may be submerged under future sea level rise) has been rarely explored. Using the Dongshan Bay in southern China as a reference site, we explore numerically the effects of geological constraints (i.e., islands) on the long-term morphodynamics of back-barrier basins. Model results indicate that the spatial configuration of mouth islands can considerably affect the morphological development of tidal basins. The presence of mouth islands can increase both the current velocity and the residual current by narrowing the inlet cross-sectional area, resulting in more sediment suspension and transport. Meanwhile, erosion tends to occur in the tidal basin and sedimentation occurs in the ebb-delta area, and the erosion (or sedimentation) volume is larger with the presence of more mouth islands. Further, the spatial distribution of mouth islands can also considerably affect tidal basin evolution: the basin-side mouth islands tend to cause more basin erosion with higher tidal currents and more sediment transport, while the delta-side ones may play a hindering role resulting in sediment deposition in the basin. Finally, larger tidal prisms are observed in basins with more mouth islands and those with basin-side mouth islands, suggesting that the number and location of mouth islands can also affect the empirical relation between tidal prism and inlet cross-sectional area. This modelling study furthers the understanding of barrier basin morphodynamics affected by mouth islands and informs management strategies under a changing environment.

Yizhang Wei et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on esurf-2021-46', Zheng Bing Wang, 13 Aug 2021
    • AC1: 'Reply on RC1', Zeng Zhou, 02 Sep 2021
  • RC2: 'Comment on esurf-2021-46', Anonymous Referee #2, 10 Sep 2021

Yizhang Wei et al.

Yizhang Wei et al.

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Short summary
Barrier tidal basin is increasingly altered human activity and sea-level rise. These environmental changes probably lead to the emergence or disappearance of islands, yet the effect of island on the evolution of tidal basin remain poorly investigated. Using a set of numerical experiments, we explore the evolution of tidal basins under varying numbers and locations of islands. This study provides insights for predicting the response of barrier tidal basins under a changing environment.