Hillman Marsh Barrier Beach Restoration Project Moving Forward

A conceptual rendering of the preferred barrier beach restoration option to maximize Hillman Marsh’s ecological functioning and resilience to climate change. Photo courtesy of Resolution Studio & SJL Engineering.

The ERCA Board of Directors has approved a plan  to create a stable barrier beach at Hillman Marsh that effectively protects the marsh from large waves, extreme storm events, and future climate change stressors.  This barrier will allow for the survival of submergent, emergent, and floating wetland vegetation, which will subsequently improve water quality, act as a stabilizer for the barrier beach, and provide quality habitat for various species.

The modelling was based on the preferred restoration concept, which was chosen following an 18-month consultation process that included municipal, provincial, and federal governments, academia, NGOs, consulting and engineering firms, First Nations, and local representatives. The modelling exercise was based on decades of data that included bathymetric survey and sonar imaging, topographic surveys, aerial imagery, wave and water level data, and more. This engineering work represents the second phase of this multi-year project. Phase 1 of the restoration work was undertaken in 2024, and included stabilizing a section of the eroding shoreline to improve its resilience to climate change, using both traditional engineering and nature-based solutions.

A 1 to 40 scale physical model was constructed at the National Research Council of Canada’s Ocean, Coastal and River Engineering Research Centre in Ottawa to test the concept’s resilience against various wave and water level scenarios, including the 100-year event. “This was an important step, and while costly, it allowed us to optimize the design and reduce the anticipated construction cost estimates by roughly $3 million,” explained Seth Logan of SJL Engineering. “It also provided added confidence that the design would perform well and meet our project objectives for the most severe conditions expected throughout its design life.”

Various historical storm events were simulated to pinpoint the specific storms that contributed to the failure of the barrier beach, and five potential restoration concepts were tested against various current speeds, wave heights, water levels and storm events to predict how well each concept would fare in future climate change extremes.

“This restoration work is extremely important to ensure the long-term ecological health of the marsh and to improve water quality leaving these watersheds, and also to assist with protecting the homes in this east Leamington area,” said Kevin Money, ERCA’s Director of Conservation Services.

The next step of this project is the detailed design development and costing, with hopes that the final engineering will be completed and ready for tender in 2026.

A 1 to 40 scale physical model was constructed at the National Research Council of Canada’s Ocean, Coastal and River Engineering Research Centre in Ottawa, to test the concept’s resilience against various wave and water level scenarios, including the 100-year event. Photo courtesy of SJL Engineering.