Beach profile morphological changes: northeast Graham Island, Queen Charlotte Islands, British Columbia, Canada

Date

2009-11-04T23:16:48Z

Authors

Zantvoort, Willem Gerald

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Abstract

The northeast coast of Graham Island is macrotidal, composed of unconsolidated sediments, and subject to extreme wind and wave conditions. Cape Fife coast is erosive, composed of sand to gravel, and is medium to low sloped with intertidal to subtidal bars. The north coast is mainly depositional, very low to steeply sloped, and composed of fine aeolian sands and cobbles. Rose Spit, trending north-northeast separates the two beaches. Cross-shore profiles documented seasonal morphologies, where active summer swash bar development is preceded by concave profile. This study identified that bars on the east coast are linked to erosive hotspots. There was a relationship between wavelength and amplitude of the bar and the erosive nature of the foreshore. It is proposed that bars protect against incident waves. Decadal and seasonal evolution of a portion of the northeast coast was compiled with the combination of aerial photography, bathymetric data and geomorphological mapping.

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Keywords

Morphology, Erosion

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