Bluff Erosion Along the Southeastern Coast of Lake Huron

This study quantifies the change in position of bluffs along the coast of Lake Huron. A bluff is a type of soft sediment cliff that borders a coastal area and is prone to progressive erosion through weathering processes. In Ontario, coastal bluffs along the Laurentian Great Lakes shoreline are highly developed. Erosion can result in damage to personal property, infrastructure, recreational services, and ecosystems. Therefore, it is important to gain an understanding of the spatially dependent rates of bluff retreat. Two sites were selected along ~2 km of shoreline due to the presence of continuous bluff environments, located south of Goderich and north of Grand Bend. Using air photos from between 1966 and 2020, the shoreline, base, and brink of the bluff were digitized using ArcGIS Pro. About 200 to 300 transects were then automatically generated and were located at 10 m intervals alongshore. The rate of shoreline and bluff retreat (m/y) and total change (m) were determined to be more than 3 m/y and a total of 50 m. Identifying these areas could lead to further research into the mechanisms causing an increase in localized erosion and can be used to inform further coastal hazard risk assessments and management.