Is NCC boardwalk plan worth its price tag?

One appealing idea in the National Capital Commission’s draft plan for the Sir John A. Macdonald Waterfront Linear Park is a boardwalk that would extend over the Ottawa River east of Deschênes Rapids.

But if a feasibility study commissioned by the NCC is any indication, the cost of the boardwalk could be high — potentially tens of millions of dollars. And while the study concludes that the boardwalk project is feasible, it also warns that ice loading will be a “challenging aspect” of the design process.

The study, done by W.F. Baird & Associates and released under access to information, provides no cost estimate for the boardwalk.

However, it offers “indicative costs” for three different structural configurations, ranging from as little as $3,000 per linear metre for a shore-tied rubble-fill revetment to as much as $25,000 per linear metre for a concept that includes artificial islands.

For the entire 2,200-metre boardwalk envisaged by Baird, those costs translate into a total price tag between $6.6 million and $55 million, depending on which structural configuration was selected.

In a high-level concept plan it developed for discussion and planning purposes, Baird used a mix of floating boardwalks, piled structures, and rubble-fill revetments and artificial islands. It’s hard to imagine that such a boardwalk would cost less than $20 million — and perhaps considerably more.

In an email, NCC spokesman Jean Wolff said the proposed boardwalk is one of several longterm ideas being examined for the riverfront park, which the NCC hopes will become “a hallmark front lawn” in the nation’s capital.

He said the Baird report “provides a very preliminary estimate of costs that will vary subject to more detailed work, including environmental regulatory approval and geotechnical issues that will play a role in future decisions and costing.”

The report recommends minimizing the amount of in-water construction to reduce costs, risk and environmental disturbances, adding: “This can be accomplished by keeping the alignment along (or near) the shoreline where possible.”

The three- to four-metre-wide boardwalk would extend between the mouth of Pinecrest Creek to a point about 1.7 kilometres to the east. It would be a “low-speed contemplative recreational experience,” restricted to pedestrians or cyclists walking their bikes.

Under Baird’s concept plan, the boardwalk would include three small artificial islands and an elevated lookout that would provide a closer view of Deschênes Rapids and the surrounding shoreline. Farther east, it would make use of a rock beach at a lower grade than the existing pathway.

The Baird study says the design will likely be modified and refined significantly prior to construction.

“It is obvious that more study relating to the governing conditions is required, with environmental/ regulatory restrictions and ice loading anticipated as being two critical elements in the planning and design of this project.”

Once a preferred alignment is chosen, the study recommends that specific ice loads should be estimated during the preliminary design phase.

“This will help determine whether the project is viable from a financial (and environmental) point of view in case the ice loading causes the design to become overly robust.”

The consultants add, however, that they believe it’s possible to design a structure capable of withstanding the ice loads at the site.

They also suggest a review of nearby established habitats should be done to develop guidelines to create new habitat “that will function and thrive in a similar manner.”

As well, there should be an assessment of how the proposed boardwalk could affect the nearby Mud Lake/Britannia Conservation Area, the study says.

The project provides an opportunity to improve both the site ecology and users’ recreational experience, it says, “mutually benefiting the public and the environment.”

More study relating to the governing conditions is required.