Rotary Park Boardwalk

PROJECT BACKGROUND

About the Project

• The project includes a new raised boardwalk along the Lake shoreline and a new trail section connecting to the existing Ajax Waterfront Trail and Trans-Canada Trail.
• The new boardwalk will consist of metal and wood structure spanning the mouth of Duffin’s Marsh.
• The new boardwalk will provide a connection between Duffin’s Pedestrian Bridge to Rotary Park and relocate a portion of the existing trail away from the beach.
• The new boardwalk structure will be elevated above the beach and marsh area, allowing natural beach processes to occur without impacting the Waterfront Trail.

Why is this project needed?

• The existing boardwalk to the west of the site was constructed in the early 1990s and forms an important and significant link for the Ajax Waterfront Trail.
• The eastern end of the existing bridge connects with a sand/gravel trail continuing east toward Rotary Park. This segment of the trail has encountered several washouts and is in constant need of repair, it was in direct conflict with the dynamic beach.
• In order to relocate the existing trail away from the beach, a new boardwalk structure will be designed and built to the north of the existing trail, from the eastern end of the Duffin’s Pedestrian Bridge to Rotary Park.

SITE ANALYSIS

Space Limitation

• The area in which the new walkway will be constructed is in a small spit – 130m x25m – that separates Lake Ontario from Duffin’s Marsh.
• The shoreline of the spit is subject to changes in its width during the time of sediment deposition and erosion. Both its physical and biological conditions will change due to lake level fluctuation, waves /storms, and wind.
• The above factors that affect the physical and biological characteristic of the spit will continue to impact on the spit in the future.

Coastal Hazard limits

TRCA standards for Dynamic beach hazard considers the 100-year flood level, a wave uprush Allowance and an Allowance for a Dynamic Beach. The shoreline in front of the Rotary Park Boardwalk is a dynamic beach, therefore, the following allowances are applied:

• The 100-year lake flood level of 75.6m plus a 15m allowance for uprush, and
• Additional 30m allowance for dynamic beach movement.

Design Recommendations

The above noted 45m total setback limit from 100-year flood level (75.6m) extends well into the ecologically sensitive marsh which is not a feasible location to place the boardwalk.

The construction of an elevated boardwalk is preferred for the following reasons:

• It allows unimpeded movement of plants across the spit (i.e., below the boardwalk);
• It allows a large area for plants and hence more stabilization of the spit by plants/roots;
• It allows movement of water and sediment across the spit during times of storms and High lake levels, thus contributing to the natural dynamic coastal cycles;
• It allows small animals to move from the marsh to the shoreline;
• Being an elevated boardwalk, there will be less contact by people with the natural system allowing the natural processes to develop more naturally;
• Being elevated, with the physical environment (water, sediments, and plants) will not interfere with the operation of the boardwalk.

ENVIRONMENTAL IMPACT

Overall, the level of impact from the development will be localized and is not expected to be significant due to the minor scale, proposed design and type of construction method. The proposed asphalt trail will occur in the manicured portion of the Rotary Park (cultural parkland) and therefore no adverse impacts are expected from this project component. No adverse impacts to significant natural features will occur from the development.

Mitigation Measures

• Wildlife and Wildlife Habitat - Construction activities (e.g. vegetation clearing, grading, construction, etc.) will be scheduled outside of sensitive wildlife breeding periods, in southern Ontario is from April 15 - July 15.
• Soil and Water - Soil and water on the Site could be potentially contaminated by sediment and chemical spills (e.g. diesel, hydraulics, lubricants, solvents, etc.) during construction.
• The framework and metal rails for the boardwalk will be Corten steel (no painting) to avoid paint chips entering the environment.
• Erosion and Sediment Control (ESC) measures will be installed to prevent sedimentation into the marsh and Lake Ontario. Spill prevention measures will be implemented including designated refuelling areas a safe distance from surface waters; using primary and secondary fuel storage containment; keeping spill clean-up kits on site; regular equipment maintenance; and daily checks, etc.
• Vegetation - Some vegetation removal will occur from the proposed boardwalk; however, the extent of vegetation loss will be minimized. Half of the proposed alignment for the boardwalk will follow the existing waterfront trail and primarily avoids mature trees. The proposed alignment for the asphalt trail is through the cultural parkland and no natural vegetation will be removed.