• Canadians recognize the benefits of physical activity, but like their neighbors to the south, sometimes they need help finding ways to exercise. Launched in 1999, the Coalition for Active Living encourages communities to adopt policies and implement projects that make it easier for residents to cycle, walk, roller-blade, and run.

    One such community is Brackley, a farmtown in the province of Prince Edward Island, where a link to a regional trail system is under construction. The 1.62-mile section is part of a larger installation to connect neighboring downtown Charlottetown to the south to the Confederation Trail along the island’s north coast.

    Ultimately, 11.8 miles of trail will run next to a two-lane arterial road that runs from Charlottetown to Prince Edward Island National Park. Instead of the shoulder, users will be separated from traffic in the road’s former drainage ditch.

    The land previously devoted to the ditch now: conveys stormwater in an enclosed structure;

  • increases the area’s scenic appeal;
  • adds an attraction that can be used by tourists and residents of the community and surrounding areas.

HDPE pipe cover specs

Most of Brackley’s section was built by installing corrugated high-density polyethylene (HDPE) pipe in the ditch, backfilling, and covering. The 12-, 15-, 18-, and 24-inch SolfloMax pipe, made by Soleno Inc. at its McAdams, New Brunswick plant, which has a bell with an integrated, gasketed spigot for watertight performance, is buried 5 feet to 6 feet deep.

“A lot of the new trail is on top of the pipe,” says Hubert Fraser, technical services manager for Campbell’s Concrete Ltd., the Charlottetown distributor that supplied pipe, fittings, and technical support. “The pipe stands up to the weight of the deep fill, provided it’s installed correctly with appropriately compacted backfill materials.”

According to the Plastics Pipe Institute Inc. (PPI), properly installed HDPE corrugated pipe can withstand AASHTO HS-25 loads with a minimum of 1 foot of cover for diameters up to 48 inches and 2 feet for larger diameters. If installed under pavement in colder climates, the institute recommends 2 feet of cover or one-half the pipe diameter, whichever is greater.

Ten to 20 years ago, island engineers would have specified concrete and steel for the job, particularly since most of the water is groundwater and stormwater runoff as opposed to saltwater. But as they’ve worked with the material, the use of corrugated HDPE pipe for drainage on the island has grown rapidly.

“More than 90% of our stormwater drainage projects are now HDPE,” Fraser says. “This is due to improved availability, price, and ease of installation. Plus, it’s environmentally friendly and the flow rates are better than corrugated steel pipe.”

The project was designed by Adam Clark, PE, of the Charlottetown office of CBCL Consulting Engineers Ltd., headquartered in Halifax, Nova Scotia.

“This was a pretty typical job for us,” he says. “The motivation was to rid the community of the ditch and turn it into something usable and environmentally sound. It’s a gravity-fed system with catch basins along the way and it discharges into a downstream watercourse. We sized it to be able to accommodate a 25-year event.”

Project funding came from Canada’s gas tax and public transit capital trust funds.

“The increase in corrugated HDPE pipe use is easy to understand,” says PPI Executive Director Tony Radoszewski. “It’s manageable and installs quickly and economically, sometimes without heavy equipment. Plus you get immediate, quality joints from the bell with integrated gasket configuration. HDPE stands up to virtually any harsh chemical.

“Using the pipe to infill a ditch and construct a trail is another excellent example of innovative thinking. I’m sure many other communities will follow what Brackley has done.”

Steve Cooper is a freelance writer based in New York City. E-mail [email protected]