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TitreHigh water levels in Big Lake, caused by Hurricane Dorian (Sept. 7, 2019) and changes to Long Beach, Nova Scotia
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LicenceVeuillez noter que la Licence du gouvernement ouvert - Canada remplace toutes les licences antérieures.
AuteurTaylor, R B; Fraser, P; Kostylev, V; Potter, D P; Forbes, D L; Whalen, D; Robertson, A; Leys, V
SourceCommission géologique du Canada, Dossier public 8760, 2021, 31 pages, https://doi.org/10.4095/327835 (Accès ouvert)
Image
Année2021
ÉditeurRessources naturelles Canada
Documentdossier public
Lang.anglais
DOIhttps://doi.org/10.4095/327835
Mediaen ligne; numérique
Formatspdf
ProvinceNouvelle-Écosse
SNRC11D/11
Lat/Long OENS -63.5000 -63.0000 45.2500 44.5000
Sujetsmilieu côtièr; érosion côtière; cordons littoraux; chenaux de marée; eaux de surface; lacs; fluctuations de niveaux des puits; météorologie; tempêtes; milieu hydrologique; pression; temperature; conductivité; marées; inondations; variations du littoral; changements du niveau de la mer; océanographie; topographie; télédétection; méthodes photogrammétriques; interprétation de photos aériennes; instruments d'observation; hydrologie; vent; infrastructure; changement climatique; effets cumulatifs; données géographiques; système de positionnement global; véhicules aériens; hydrogéologie; géologie des dépôts meubles/géomorphologie; géologie marine; géologie de l'environnement; géophysique; Nature et environnement; Sciences et technologie
Illustrationsphotographs; location maps; satellite images; aerial photographs; digital elevation models; time series; tables; plots; profiles
ProgrammeGéosciences de changements climatiques, Infrastructure côtière
Diffusé2021 01 13
Résumé(disponible en anglais seulement)
Hurricane 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.
Résumé(Résumé en langage clair et simple, non publié)
Mise à jour des recherches concernant la destruction d'une plage de barrière de haut gravier (Long Beach, Nouvelle-Écosse) et la formation d'une passe qui a transformé un étang côtier (Big Lake, Nouvelle-Écosse) en une lagune à marée. Les impacts de l'ouragan Dorian de Septembre 2019 sur la stabilité de Long Beach et les niveaux d'eau extrêmes dans la lagune à marée ont été évalués en tant que dangers d'inondations pour les résidents vivant le long de la lagune.
GEOSCAN ID327835