Highways·Prince Edward Island·—·Prince Edward Island

Prince Edward Island Intertidal Reef Highway Protection

2,400 tonnes sandstone reefs · 45m offshore · Trans-Canada Highway protected

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Key insight

Nature-based reefs using locally sourced stone achieved beach protection at a fraction of the cost of traditional hard armour, while also improving biodiversity and avoiding the erosion acceleration typical of conventional sea walls.

Transferability to UK: MediumIntertidal reef approach applicable to UK coastal road and rail infrastructure at risk from storm erosion and sea level rise.

Two intertidal reefs totalling 2,400 tonnes of locally sourced sandstone were installed 45 metres offshore to protect the Trans-Canada Highway at Souris from sea level rise, storms and coastal erosion — the first intertidal reefs built on Prince Edward Island. The nature-based solution attenuates wave action and promotes beach-dune growth, providing adaptive capacity as sea levels rise.

Climate drivers

Sea level riseStorms and high winds

Impacts

→Coastal erosion→Highway flooding→Dune breach

Adaptation measures

  • Intertidal reef construction
  • Dune restoration
  • Shoreline stabilisation
  • Adaptive management

Assets affected

Road pavementCoastal highway

Investment

CAD $115,000 (approx. £67k); shared federal/provincial funding

Band: Under £1m

Delivery period

—

  • The Trans-Canada Highway (Highway 2) faced challenges from sea level rise, storms and shoreline erosion as it approached the town of Souris on Prince Edward Island (PEI), Canada.
  • This portion of the highway is only a few hundred metres from the shoreline, crossing the Souris River and running along the low-lying Souris Spit.
  • The causeway into the town is a vital conduit for the local economy, which is heavily dependent on tourism and fishing. With a population of 1,079 based on the 2021 census, any disruption due to storms could significantly impact the community and livelihoods.
  • In January 2016, a winter storm highlighted the vulnerability of the highway to erosion and inundation, eroding the small dune system along the beach and bringing flood waters to the edge of the highway.
  • A post-storm survey indicated that a subsequent storm would be capable of breaching the dunes and allow waves to reach the highway’s edge, leading to the temporary closure of Highway 2 and associated repair costs. The rising sea levels, reduced ice cover, and changing storm patterns associated with climate change exacerbate this risk.

Ref: ID_02 · Prince Edward Island · Curated & verified by HIVE

Transferability to UK: Medium

Intertidal reef approach applicable to UK coastal road and rail infrastructure at risk from storm erosion and sea level rise. Requires appropriate coastal geology and adequate space for reef placement.

UK contexts

UK coastal highwaysCoastal rail lines in erosion-risk zonesLow-lying coastal transport corridors

Applicable to UK coastal

Transfer to other sectors (AI)