Assessing the impact of hurricane Fiona on the coast of PEI National Park and implications for the effectiveness of beach-dune management policies

Abstract

The impact of waves, storm surge, and aeolian transport associated with Post-tropical Storm Fiona (offshore significant wave height ∽ 8 m, storm surge up to 2 m) on the sandy beaches and foredunes of the north shore of Prince Edward Island National Park (PEINP), Canada, are assessed. Management policies and practices, as they apply to sandy beach systems within PEINP, are reviewed in the context of the shoreline changes attributed to Fiona. The effectiveness of these policies and practices are evaluated to inform the potential performance of beach-foredune systems as natural protection measures that mitigate the impacts of large-magnitude storms and relative sea-level rise (RSLR) on shoreline change. The analyses utilise survey data, ground photography, and unoccupied aerial vehicle (UAV) imagery collected before (October 2021 to July 2022) and after (October 2022 and May 2023) Fiona. In general, the largest dunes were characterised by erosion of the stoss slope, with landward retreat of the dune toe by < 6 m and minimal impact on crest height and position. Small foredunes (< 5 m in height) generally showed significantly greater erosion in terms of dune profiles, with dune breaching occurring at some locations. Foredunes perched on bedrock and till, which were typically smallest in size, were subject to complete erosion, thereby exposing the hard underlying surface. Overall, the impact of Fiona on sandy beach systems in PEINP was relatively modest in many locations, reflecting the success of existing management policies and practices that protect and maintain the integrity of foredunes by minimizing human impacts and avoiding ‘coastal squeeze’.