Beach profiles constructed from elevation data were used to evaluate the seasonal
cross-shore morphological changes along three transects in Boundary Bay, British
Columbia, Canada. GPS/GIS data was utilized for the analysis of the seasonal migration
of the upper shoreface at each transect and along the entire length of the shoreline. The
data was compared to the model of seasonal beach change that indicates winter beach
erosion/retreat and summer beach accretion/progradation. The trends observed in
Boundary Bay exhibited winter beach accretion/progradation and summer beach
erosion/retreat and this was in contrast to the generalized model. The results may be
attributed to the southerly orientation of the mouth of the bay. During winter, storms
arrive from the south and enter the bay directly and enhance erosion from the Point
Roberts headland and increased longshore sediment drift. The northwesterly wind
direction in the summer results in reduced longshore sediment transport and less sediment
entering the bay. There was no observable impact of the mitigation structures on the
morphology of the beach profiles
