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TitleMechanisms, volumetric assessment, and prognosis for rapid coastal erosion of Tuktoyaktuk Island, an important natural barrier for the harbour and community
AuthorWhalen, DORCID logo; Forbes, D LORCID logo; Lim, M; Fraser, P; Kostylev, V; Nedimovic, M; Stuckey, S
SourceCanadian Journal of Earth Sciences 2022 p. 1-60, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20210176
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
Lat/Long WENS-134.0000 -133.0000 69.5000 69.2500
Subjectsenvironmental geology; Health and Safety; Nature and Environment; erosion; permafrost; climate, arctic; climate; Climate change; cumulative effects; Communities
Illustrationslocation maps; cross-sections, stratigraphic; photographs; graphs; profiles; histograms
ProgramClimate Change Geoscience Coastal Infrastructure
Released2022 08 04
AbstractThe coastline of the Inuvialuit Settlement Region (ISR) in the Mackenzie -Beaufort region of the western Canadian Arctic is characterised by rapid erosion of ice-bonded sediments with abundant excess ground ice, resulting in widespread thermal and mechanical process interactions in the shore zone. Coastal communities within the ISR are acutely aware of the rapidly eroding coastline and its impacts on infrastructure, subsistence activities, cultural or ancestral sites, and natural habitats. Tuktoyaktuk Island is a large natural barrier protecting the harbour and surrounding community from exposure to waves. It is threatened by coastal erosion, a better understanding of which will inform adaptation strategies. Using historical and recent aerial imagery, high-resolution digital elevation models, cliff geomorphology, stratigraphy, and sedimentology, including ground-ice content, this study documents erosional processes, recession rates, volume losses and sediment delivery since 1947, and projected into the future. Erosion along the northwest-facing (exposed) cliff, primarily by thermo-abrasional undercutting and block failure, has accelerated since 2000 to a mean of 1.8 ± 0.02 m/yr, a 22% increase over the previous 15 years and 17% faster than 1947-2000. Lower recession rates on the harbour side of the island increased more than two-fold. Projection of future shoreline vectors by extrapolation, using the post-2000 accelerated coastal recession rates at 284 transects, points to breaching of this vital natural harbour barrier by 2044, after which rapid realignment is expected to occur as the new inlet evolves. Further acceleration of rates, as seems highly likely, brings the breaching date closer.
Summary(Plain Language Summary, not published)
This paper look at the longterm erosion of Tuktoyaktuk Island, which serves as a natural breakwater for the community of Tuktoyaktuk and Tuktoyaktuk Harbour. Here we analyse aerial imagery (1947 to present) to establish that the average yearly coastal retreat rate at Tuktoyaktuk Island is 1.8 m/yr. If this rate of erosion continues, this vital natural harbour would be exposed to wave action within 23 years following breach of the Island. A better understanding of short and long-term sediment dynamics of Tuktoyaktuk Island in this rapidly changing environment is critical to making accurate projections of the future change and developing appropriate adaptation strategies.

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