Cap-des-Rosiers coastal road relocation and beach restoration

Looking to replenish the degraded natural environment of Cap-des-Rosiers beach and to eliminate the cost of maintaining and repairing the damaged coastal road and infrastructures, Parks Canada selected WSP to conduct a hydrodynamic study of the coastal processes and develop several restorative solutions that will limit submersion and erosion due to sea level rise.

In recognition of the environmental and financial cost of maintaining and repairing the roads and infrastructure found along the shoreline of Cap-des-Rosiers beach, Parks Canada set out to relocate the road and replenish the environment through the pursuit of a three-year restoration project. As the project entailed the relocation of the coastal road and a monument, as well as restorative operations for the coastal zone, Parks Canada retained WSP to conduct a hydrodynamic study and develop sustainable solutions to preserve the longevity of the beach and park infrastructures.

 

Effects of Climate Change on Coastal Infrastructure

Constructed in 1927, the road between the beach and the lighthouse sustained recurrent damage from spring tides and violent storms exacerbated by the effects of climate change. Though many shore protection works had been built over the years, including the installation of new riprap along the 2km-long littoral in 1980, the damage made to the structure rendered costly maintenance and repair fees for Parks Canada. It was also evident that the successive construction of the road and shore protection works aggravated the effects of shoreline erosion, degrading the environment and threatening the integrity of the cultural and natural elements of Caps-des-Rosiers beach. For these reasons, Parks Canada sought to demolish the existing road, relocate coastal infrastructures and construct a new road 200m inland.

 

Our Approach

The project was carried out in three phases:

Phase 1 – Hydrodynamic study of the littoral in l’anse de Cap-des-Rosiers.
Phase 2 – Preparation of the design and specifications for the restoration solution.
Phase 3 – Construction supervision and contract administration.

During Phase 1, our team performed a hydrodynamic study of the coastal zone to characterize the hydrodynamic and sediment conditions using wave modelling and a literal sediment transport model. We assessed the impact of removing the existing riprap and determined the long-term erosion and submergence risk along the coast. We considered the need to improve spawning potential for the capelin along the littoral when developing restorative options and assessed the impact of our proposed solutions on the different elements such as the harbour and marshes found within the vicinity.

Once the recommendations for beach restoration and safe development of the coastal zone were made, we proceeded to Phase 2 in which we oversaw the design and preparation of the design and specifications for the construction work. This included rock revetment and road demolition, beach restoration; rock revetment along Quebec Route 132 and near the Cap-des-Rosiers wharf; creation of a new location for the Carrick Memorial Monument; and development of new wooden boardwalk paths along the coast. Finally, during Phase 3, we performed the construction supervision and contraction administration, ensuring the sound delivery of the desired outcomes.

 

Outcome

Through the project, Parks Canada demonstrated its leadership in addressing the effects of climate change, garnered a new natural coastal environment, and eliminated the need for repeated maintenance and repair of the coastal road and shore protection works.