Decadal shoreline erosion and recovery of beaches in modified and natural estuaries

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dc.contributor.authorFellowes, Thomas E.en_NZ
dc.contributor.authorVila-Concejo, Anaen_NZ
dc.contributor.authorGallop, Shari L.en_NZ
dc.contributor.authorSchosberg, Ryanen_NZ
dc.contributor.authorde Staercke, Vincenten_NZ
dc.contributor.authorLargier, John L.en_NZ
dc.date.accessioned2021-08-09T23:00:59Z
dc.date.available2021-08-09T23:00:59Z
dc.date.issued2021en_NZ
dc.description.abstractSandy beaches in estuaries and bays (BEBs) are common landforms on the coasts of many major cities. They exist under a wide range of settings and their morphology is controlled by their distance from the estuary/bay entrance, exposure to different types of waves (e.g., ocean swells vs locally generated wind waves), proximity to flood-tide delta/shoals, and anthropogenic interventions (e.g., dredging, groynes). Both swell waves propagating into estuaries/bays and locally generated wind waves can erode BEBs. However, more understanding of BEB storm erosion and recovery over decadal timescales is needed, as they typically respond slower than open coast beaches. Here we present decadal shoreline behaviours of nine BEBs from two estuarine systems in SE Australia are presented in this study, using 76 years of aerial imagery (1941–2017). We quantify and compare decadal behaviour between beaches, developing a new typology of BEBs based on shoreline evolution. We identify four decadal behaviours: prograding, quasi-stable, retreating and storm relict – and assess the influence of flood-tide deltas, river mouths, distance from the ocean entrance, and anthropogenic interventions. Swell-exposed BEBs near the entrance are quasi-stable and recover after storms at rates comparable with open coast beaches (<3 years). In contrast, BEBs further from the entrance and those with less swell exposure, have slower recovery timescales (3–15 years) and will only be quasi-stable if storms are sufficiently infrequent. Thus, long-term behaviour is controlled by storm return timescales. Prograding BEBs are typically far from the entrance, where fluvial and tidal processes dominate and erosion events due to wind waves are less pronounced. Whether BEBs recover (quasi-stable), partially recover between storms (retreating) or never recover (storm relict) relates to storm frequency, recovery rates and proximity to sediment sources and sinks (e.g., dredge sites, flood-tide deltas, tidal channels) and anthropogenic interventions. Findings will help to better understand and manage BEB shorelines in major cities.
dc.format.mimetypeapplication/pdf
dc.identifier.citationFellowes, T. E., Vila-Concejo, A., Gallop, S. L., Schosberg, R., de Staercke, V., & Largier, J. L. (2021). Decadal shoreline erosion and recovery of beaches in modified and natural estuaries. Geomorphology, 107884–107884. https://doi.org/10.1016/j.geomorph.2021.107884en
dc.identifier.doi10.1016/j.geomorph.2021.107884en_NZ
dc.identifier.issn0169-555Xen_NZ
dc.identifier.urihttps://hdl.handle.net/10289/14518
dc.language.isoenen_NZ
dc.publisherElsevier BVen_NZ
dc.relation.isPartOfGeomorphologyen_NZ
dc.rights© 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.titleDecadal shoreline erosion and recovery of beaches in modified and natural estuariesen_NZ
dc.typeJournal Article
pubs.begin-page107884
pubs.elements-id263657
pubs.end-page107884
pubs.organisational-group/Waikato
pubs.organisational-group/Waikato/2025 PBRF
pubs.organisational-group/Waikato/DHECS
pubs.organisational-group/Waikato/DHECS/2025 PBRF - DHEC
pubs.organisational-group/Waikato/DHECS/SCHS
pubs.organisational-group/Waikato/DHECS/SCHS/2025 PBRF - SCHS
pubs.organisational-group/Waikato/FSEN - Old
pubs.organisational-group/Waikato/FSEN - Old/School of Science
pubs.organisational-group/Waikato/FSEN - Old/School of Science/2018 PBRF - School of Science
pubs.publication-statusPublisheden_NZ
pubs.user.infoGallop, Shari (sgallop@waikato.ac.nz)
uow.identifier.article-no107884
uow.verification.statusverified
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