Breach in the Barrier Beach at Cranberry Marsh in Lynde Shores Conservation Area

For the third spring in a row, the barrier beach at Cranberry Marsh in Lynde Shores Conservation Area has broken, allowing water to drain from the Marsh into Lake Ontario. While the breach closed again (April 5) after a few weeks, it remains vulnerable.

Location of the breach for 2024 (image), 2025, and 2026.

Why does this happen?

Coastal wetlands like Cranberry Marsh are naturally dynamic. Barrier beaches regularly open and close depending on water levels and weather conditions. These natural changes are an important part of coastal wetland function, helping to maintain wetland health and biodiversity.

However, this beach is under increased pressure from long-term erosion. Changes to the shoreline, including hardened areas and jetties, have reduced the natural movement of sand along Lake Ontario and have limited the overall supply of sediment. As a result, Cranberry Marsh’s barrier beach is continuing to erode, has a reduced ability to withstand wave and water level changes over time, and has less capacity to naturally repair itself. High water levels in 2017 and 2019 also played a role by exposing the beach to greater wave impact, allowing waves that would normally break at the shoreline to flow over the crest of the barrier.

What are we doing about it?

As a temporary measure, two large dead trees at the site of the breach were cut up and moved in 2025 to try to assist with a full beach repair. Within a week or two, strong south winds, waves, and a storm completely filled in the beach!

Short-term solutions, such as filling the breach, are temporary and can create additional issues elsewhere along the shoreline. CLOCA is currently in year two of a three-year, federally funded project to develop a long-term solution. Year one focused on gathering background information, including detailed studies on wave conditions, sediment movement and supply, water levels, and barrier beach conditions such as sediment composition and vegetation surveys (existing vegetation plays an important role in stabilizing the shoreline and helping to trap sediment). This year and next year will focus on developing and testing design options through modelling to identify a preferred long-term approach and

support future implementation and funding. We will continue to monitor conditions and share updates as this work progresses.

Learn More About Restoration Projects at Lynde Shores

Contact:

Michael Grieve, Wetland Biologist

Central Lake Ontario Conservation Authority

mgrieve@cloca.com