Print Email Facebook Twitter Morphodynamic adaptation of a tidal basin to centennial sea-level rise Title Morphodynamic adaptation of a tidal basin to centennial sea-level rise: The importance of lateral expansion Author Guo, Leicheng (East China Normal University) Xu, Fan (East China Normal University) van der Wegen, Mick (IHE Delft Institute for Water Education; Deltares) Townend, Ian (University of Southampton) Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares) He, Qing (East China Normal University) Date 2021 Abstract Global climate changes have accelerated sea-level rise (SLR), which exacerbates the risks of coastal flooding and erosion. It is of practical interest to understand the long-term hydro-morphodynamic adaptation of coastal systems to SLR at a century time scale. In this work we use a numerical model to explore morphodynamic evolution of a schematized tidal basin in response to SLR of 0.25–2.0 m over 100 years with special emphasis on the impact of lateral basin expansion. Starting from a sloped initial bed, morphodynamic development of the system leads to the formation of alternating bars and meandering channels inside the tidal basin and an ebb-tidal delta extending seaward from the basin. Imposing rising sea level causes progressive inundation of the low-lying floodplains, found along the basin margins, inducing an increase in basin plain area and tidal prism, as well as intertidal area and storage volume. Although the overall channel-shoal structure persists under SLR, lateral shoreline expansion alters the basin hypsometry, leading to enhanced sediment export. The newly-submerged floodplains partly erode, supplying sediment to the system for spatial redistribution, hence buffering the impact of SLR. The vertical accretion rate of the tidal flats inside the tidal basin lags behind the rate of SLR. However, lateral shoreline migration under SLR creates new intertidal flats, compensating intertidal flat loss in the original basin. In contrast, a constrained tidal basin without low-lying floodplains is subject to profound drowning and tidal flat losses under SLR. Overall, the model results suggest that an unconstrained tidal system allowing lateral shoreline migration has buffering capacity for alleviating the drowning impact of SLR by evolving new intertidal areas, sediment redistribution and morphodynamic adjustment. These findings suggest that preserving tidal flats located along the margins of tidal basins (instead of reclaiming them) sustains the system's resilience to SLR. Subject Accommodation spaceMorphodynamic modelingSea-level riseTidal basin To reference this document use: http://resolver.tudelft.nl/uuid:7722accf-fb33-4781-8348-c85810927b94 DOI https://doi.org/10.1016/j.csr.2021.104494 Embargo date 2022-07-12 ISSN 0278-4343 Source Continental Shelf Research, 226 Bibliographical note Accepted Author Manuscript Part of collection Institutional Repository Document type journal article Rights © 2021 Leicheng Guo, Fan Xu, Mick van der Wegen, Ian Townend, Zhengbing Wang, Qing He Files PDF MS_SLR_impact_2021_revised.pdf 2.58 MB Close viewer /islandora/object/uuid:7722accf-fb33-4781-8348-c85810927b94/datastream/OBJ/view