Protecting and Restoring PEI’s Coastline

In 2021, the Government of Prince Edward Island (PEI) developed expanded restoration plans for two coastal locations, Cedar Dunes Provincial Park and Basin Head Provincial Park, both experiencing ongoing and extensive impacts from sea level rise storm surge and wave-driven erosion. On opposite ends of PEI, both locations are important tourist destinations with unique beach-dune environments and include a number of amenities such as a campground, hotel, museum, and washroom facilities. These restoration projects build on an ongoing strategy to protect coastal roads, buildings and other infrastructure as well as the unique dune ecology. Identification and prioritization of restoration actions uses classification and sensitivity mapping of the shoreline along with updated coastal flood maps depicting PEI’s coastal floodplains for 2020, 2050, and 2100. Together with the Department of Environment, Energy and Climate Action, and managers of provincial properties including the Department of Economic Growth, Tourism and Culture, the Department of Transportation and Infrastructure (DTI) works collaboratively to prioritize coastal protection and develop site-specific restoration projects. DTI also conducts extensive monitoring of previous shoreline restoration projects using drone technology and land-based surveys to allow for continuous evaluation and improvement to future design techniques. Construction of both the Cedar Dunes and Basin Head Inlet restoration projects will begin in the fall of 2021.

Understanding and Assessing Impacts

The impacts of climate change have been evident and well-documented along the coast of PEI for decades. Several major storms in the early 2000’s caused unprecendented flooding and erosion and spurred action by the Government of PEI to undertake a number of important coastal resotration projects to protect infrastructure and ecosystems. The 2021 Climate Change Risk Assessment identifies coastal erosion as the greatest level of risk to PEI by 2050. It notes that, due to the Island’s socioeconomic and socio-cultural reliance on the coast, nearly all Islanders are likely to be directly or indirectly affected by coastal erosion in the future. Key consequences of unmitigated future coastal erosion include:

  • Potential for long-term or permanent damage to Island infrastructure, especially transportation, and wastewater infrastructure.
  • Economic impacts and widespread moderate mental health impacts, particularly as result of loss of sense of place.
  • Risk to endangered and at-risk species (e.g., piping plover) and unique natural environments (e.g., mobile parabolic sand dunes).
  • Impacts to the tourism and recreation industry, including narrowed beaches and restricted access to parks, historic landmarks, golf courses, and other resources.
  • Inundation or erosion of socio-cultural coastal communities and properties.

Identifying Actions

In 2011, the Prince Edward Island Department of Environment, Energy and Forestry developed classification and sensitivity mapping for the entire PEI shoreline. By characterizing and classifiying the shoreline, resource planners and managers can evaluate shoreline vulnerability and delineate coastal hazards, including coastal flooding, coastal erosion, and damage to coastal ecosystems. All of these hazards are influenced by the combined actions of sea level rise, tides, storm surge, reduced sea ice and wave action. This resulted in a map containing a wide range of information from shoreline type, characteristic met-ocean conditions, and coastal structures to computed littoral transport values, and estimated vulnerability to coastal flooding and erosion. In 2021, PEI released a province-wide Climate Change Risk Assessment as well as updated coastal flood maps, depicting PEI’s coastal floodplains for 2020, 2050, and 2100. Using data that was acquired by the province through the National Disaster Mitigation Program and ClimateData.ca, the updated coastal flood maps will help government, municipalities, and the public make sound planning decisions for the future. The maps also inform Coastal Hazard Assessments available for coastal properties, as well as a new series of Watershed Flood Projections Reports for developers and design professionals. Through these studies, as well as ongoing monitoring, a combination of ice-free conditions and severe winter storm activity has been shown to result in heavy erosion at a number of coastal sites including: Panmure Island, Souris, West Point and Cedar Dunes, and Basin Head Inlet. In partnership with the Department of Environment, Energy and Climate Action and the Department of Economic Growth, Tourism and Culture, the Department of Transportation and Infrastructure works collaboratively to prioritize coastal protection and restoration projects. Along with protecting critical infrastructure, recreation and tourism are important considerations when designing site-specific restoration actions for PEI’s coast.

Implementation

Protection and restoration of coastal environment has been ongoing in various priority locations since the mid-2000s, often with staged approaches. In 2012, a Langley Wall (timber crib / steel pile seawall) was constructed to protect the shoreline and vulnerable lighthouse at West Point. Ongoing monitoring showed that the structure performed well but required occassional maintenance and reinforcement, which led to the recognition that a larger adaptation project was needed. Recently, a project was launched to protect 1.5km of shoreline at the West Point / Cedar Dunes area with a series of nine inter-tidal reefs and a terminal groyne structure. Construction will take place throughout the winter of 2021 -2022. Restoration of Basin Head Inlet will also take place throughout the winter of 2021-2022. Here, a large sand dune system has eroded, and sand has choked the inlet and built-up in the estuary. Basin Head Inlet, a shallow coastal lagoon designated as a national Marine Protected Area, supports an important ecosystem and a unique type of Irish moss that may only exist within the boundaries of Basin Head. Restoration plans include re-establishing the hisorical channel location upstream of the inlet through a dredging program, combined with installing two deflector groyne structures to maintain the channel in it’s historical location over the long-term. In 2012, a Langley Wall was constructed to protect the Trans-Canada Highway at Souris, and dune restoration and shoreline stabilization works took place to restore and strengthen the existing sand beach-dune system. In 2018, two intertidal reefs were also constructed using local sandstone to dissipate wave energy, promote sand deposition, and enhance longer-term stabilization of the sand beach-dune system. In 2006, 750m of shoreline was protected and reinstated at Panmure Island with a two-tier revetment structure covered with beach sand and native plants.

Outcomes and Monitoring Progress

The Department of Transportation and Infrastrucutre monitors the effectiveness of shoreline projects using drones, often in partnership with the University of PEI, as well as standard land-based surveys. The monitoring and success of the project at Souris supported implementation of similar project work at Cedar Dunes and Basin Head Inlet. Undertaking these large projects with a staged approach has also been very successful. While nine reefs have been proposed for Cedar Dunes, they will install five of the nine reefs in 2021, and undertake monitoring to determine when additional reefs may be installed. These very visible projects have been important in bringing awareness in the community to the impacts and adaptation solutions to climate change.

Next Steps

Each site is very different and solutions must be site-specific. As pioneers in coastal engineering, the Government of PEI will continue to monitor and learn project-by-project, incorporating lessons learned. To date, they have been able to protect the majority of assets without undertaking relocation efforts. Construction of both the Cedar Dunes and Basin Head Inlet restoration projects will take place throughout the winter of 2021-2022.

Resources

Link to Full Case Study

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