Assessing recent shoreline change in northeastern Haida Gwaii, BC

The coastal environment is inherently dynamic; however, some regions are more vulnerable to environmental hazards. Considered one of these areas, northeastern Haida Gwaii was previously identified as one of Canada's most vulnerable regions to climate change-related impacts, including coastal erosion. Subsequently, numerous studies investigated the geomorphological conditions of this region; however, there have been no further shoreline studies since 2007. This research analyses how the shoreline near Masset, Haida Gwaii, has responded to atmospheric and oceanographic forcing between 2007 and 2022. Using the Digital Shoreline Analysis System, Geomorphic Change Detection software, and wind and wave analysis, we quantify shoreline movement and nearshore elevation changes and investigate causal mechanisms. Our findings suggest that this shoreline has been subject to a dominantly erosional regime during our observational period. Shoreline erosion has occurred heterogeneously across the coastline and has been focused at Entry Point and the Sangan River, the latter of which experienced concurrent pronounced lateral accretion. Erosive stretches were also identified along the general shoreline, where the nearshore typically experiences foredune retreat and/or dune footslope scarping. Shoreline change, wind, and wave analysis suggest that retreat occurs more frequently in the summer with longer storm durations and a dominance of longshore-directed wave energy, whereas shoreline rebuilding generally occurs in the winter. Increased longshore-directed wave energy during summers and decreased onshore, aggradational energy during winter are believed to be behind this shift towards an erosional regime. Understanding shoreline changes is an essential step toward reducing the vulnerability of coastal communities to environmental stressors.