ENGINEERING

Photo: Catherine Berris Associates Inc.

Building a better storm drain

One of the wettest cities in Canada uses plants rather than pavement to get rid of urban storm water

Receiving an annual average of more than 1.5 metres of precipitation, Abbotsford, B.C., is one of the wettest cities in Canada. To reduce the risk of flooding, the city built Fishtrap Creek Nature Park — a series of ponds and wetlands, augmented by native plantings and features such as a pedestrian bridge and shelter. Fishtrap Creek is a prototypical storm-water park: it not only provides a place for plants and bacteria to filter rain before it returns to the water table but also creates wildlife habitat and green space.

Such parks are of great interest to Robert France, who teaches watershed management at Nova Scotia Agricultural College in Truro. France is concerned about the “cocktail of contaminants” from lawn-care products, pet waste and auto exhaust that washes out of our cities after heavy rains. “It’s a major health concern,” he says. “If you see kids running in the streets in the suburbs after a storm, you could do an intervention and rip them away from their parents for letting them play in all that urban slobber.”

One of the problems is all the pavement in urban Canada. Our cities are designed to funnel away rain and snowmelt as quickly as possible, preventing water from being filtered before it returns to lakes and streams — and preventing people from seeing the water cycle at work. Storm-water parks address both issues. “We’re fostering the idea,” says France, “of having the wild in the city.”

This type of water management is not, of course, a strictly urban issue. Restoring wetlands in farmers’ fields can attract waterfowl, improve soil quality and provide a water source for livestock and irrigation. What’s more, as University of Alberta department of rural economy graduate student Katherine Packman discovered while working on a study rooted in southern Manitoba, it costs about $400 per acre to restore a wetland — a small price to pay, she says, for “significant environmental benefits.”

Ultimately, whether the setting is urban or rural, such projects can shift our understanding, showing people the value of rain and snowmelt and fostering more appreciation for water. “You won’t save what you don’t love,” says France, “and you don’t love what you don’t recognize.”