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TitleHigh water levels in Big Lake, caused by Hurricane Dorian (Sept. 7, 2019) and changes to Long Beach, Nova Scotia
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LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorTaylor, R B; Fraser, P; Kostylev, V; Potter, D P; Forbes, D L; Whalen, D; Robertson, A; Leys, V
SourceGeological Survey of Canada, Open File 8760, 2021, 31 pages, https://doi.org/10.4095/327835 (Open Access)
Image
Year2021
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNova Scotia
NTS11D/11
AreaBig Lake; Long Beach; Boland Island; Story Head Beach; Splitrock Point; Little Lake; Shagrock Point; Story Head; Chezzetcook Inlet; Atlantic Ocean
Lat/Long WENS -63.5000 -63.0000 45.2500 44.5000
Subjectshydrogeology; surficial geology/geomorphology; marine geology; environmental geology; geophysics; Nature and Environment; Science and Technology; coastal environment; coastal erosion; barrier beaches; tidal channels; surface waters; lakes; well level fluctuations; meteorology; storms; hydrologic environment; pressure; temperature; conductivity; tides; floods; shoreline changes; sea level changes; oceanography; topography; remote sensing; photogrammetric techniques; airphoto interpretation; in-field instrumentation; Hurricane Dorian (2019); hydrology; waves; wind; infrastructures; geological hazards; climate change; cumulative effects; topographic surveys; geographic data; global positioning systems; drones; Structure-from Motion (SfM) data; property damage
Illustrationsphotographs; location maps; satellite images; aerial photographs; digital elevation models; time series; tables; plots; profiles
ProgramClimate Change Geoscience, Coastal Infrastructure
Released2021 01 13
AbstractHurricane Dorian in September 2019 provided the first opportunity, since the present tidal channel opened through Long Beach in March 2019, to observe the impacts of storm generated waves and water level fluctuations along the inner shores of Big Lake. In-situ water pressure and CTD recording gauges within Big Lake provided new insights into changes in hydrology that are occurring. The accelerated deterioration of Long Beach in 2018 and 2019 and its response to the presence of an inlet marks a new phase in its evolution, which may have begun 20 years ago and possibly marks the renewal of a phase of barrier instability that prevailed before 1945.
Hurricane Dorian produced record water levels of 2.6-2.8 m (CGVD28) in Big Lake when it was tidal compared with 2.2 m (CGVD28) when it was non-tidal during Hurricane Juan (2003). In 2019, shore infrastructure along the exposed northern shores of Big Lake was damaged by strong easterly winds and waves that coincided with high tide. Waves extended onshore to a maximum elevation of 3.04 m (CGVD28). This elevation provides a basis for mapping flood hazards along this shore at present sea level. In contrast, wave run-up of 4.0 m was measured along the outer shore at Long Beach. Therefore, while the tidal inlet allowed the storm surge into the lake, the beach continued to protect inland properties against wave action during Hurricane Dorian. However, longshore changes to its crest elevation have caused differential landward shore migration. Physical response to future storms along each of the three segments of Long Beach will be different as each segment migrates landward. For the near future, the western barrier should provide the best protection for inland properties against wave attack however, with projected rises in sea level, natural stress on the barrier will continue.
Summary(Plain Language Summary, not published)
Update of a long term investigation into the breakdown of a high gravel barrier beach (Long Beach, Nova Scotia) and the formation of an inlet which has transformed a coastal lake (Big Lake Nova Scotia) into a tidal lagoon. The impacts of Hurricane Dorian in September 2019 on the stability of Long Beach and the extreme water levels produced in the coastal lagoon are assessed in terms of a flooding hazard to local residents living along the lagoon.
GEOSCAN ID327835