Torrential rains that flooded the Lower Mainland last weekend were the first test of a new community rainwater solution in Vancouver’s Mount Pleasant neighborhood.

The St. George Rainway, which is still under construction, is a City of Vancouver project designed at the request and participation of the community. It includes cobbles, dirt, and vegetation that line the east side of St. George Street as it descends from East Broadway Avenue to East Fifth Avenue.

It follows the path of an ancient buried stream and absorbs precipitation that would otherwise accumulate and flow into the street. When torrential rains reached the Lower Mainland last weekend, causing damage and mudslides across Metro Vancouver, the unfinished storm channel helped prevent street flooding.

Once completed, the four-block project will be able to drain 17,000 cubic meters of water per year from the road, or as much water as around seven Olympic swimming pools.

Meanwhile, a municipal engineer and flood researcher say projects like the St. George Rainway could be a key way to protect Canada’s neighborhoods from heavy rains.

A community-led project

The road and homes along St. George Street are built over a creek that historically flowed into False Creek. The creek still flows underground, through a series of pipes and culverts – where it has not provided the community with adequate drainage for at least a decade, often leading to street flooding and pavement damage.

Rita Wong, a local resident, said the rain would cause huge amounts of water to pour down St. George Street, often seeping into her neighbors’ basements. Street flooding contributed to the formation of cracks and potholes that marred the asphalt.

“When it rained a lot, you could see where the river was because the water was always flowing down the street,” she said. “There was a lot of water flowing down the street, and it had nowhere to stop.”

Wong said she has heard of other buried streams across the city being discovered to restore ecosystems’ natural drainage systems.

In the early 2010s, Wong and his neighbors held a series of meetings about the flooding. Together, they asked the city to find a way to restore the creek – a plan that would ultimately shape the St. George Rainway.

But according to Robb Lukes, the city’s associate director of green infrastructure implementation, uncovering the creek would require moving several homes and rerouting a gas line.

“Doing a full stream (surfacing) wasn’t going to be practical. It’s a very deep stream,” Lukes said. “But what we could do is this rain channel, which is a representation of this historic waterway.”

Instead of uncovering the creek, the city built a blocks-long garden that would mimic the creek.

The project cost $6.2 million, 60 percent of which is funded through a grant from Infrastructure Canada called the Natural Infrastructure Fund.

The project began in 2023, but construction began in earnest this summer.

The street was narrowed to make way for the rain garden. Earlier this month, the canal along St. George Street was strewn with weeds, trees and stones.

Every meter or so, a barricade called a spillway slows – but does not stop – the flow of water in the rain garden. Some blocks have benches or chairs integrated into the canal.

Lukes said the project would help prevent flooding in the neighborhood as it experiences heavier rainfall.

“It filters the runoff, absorbs it, keeps it out of the sewer system and helps maintain (drainage) capacity, as we experience more intense rainfall due to climate change,” Lukes said.

The project is the largest rain garden in the city. He said the solution would extend well along the city’s cycling corridors, where pedestrian and cyclist safety is a priority.

There are already about 300 similar rainwater projects citywide, including the tree-lined cut-and-covers that filter rainwater from downtown Richards Street — a solution Lukes says works in busier environments, such as along the Broadway Subway Extension.

“He played wonderfully”

The storm canal faced its first test last weekend when an atmospheric river flooded the Lower Mainland.

Data from Environment Canada shows precipitation records were set in Metro Vancouver. According to the city, up to 211 millimeters fell on Vancouver itself.

On St. George Street, rain infiltrated the ground and vegetation. The water flowed into the rain channel like a stream, instead of pooling in the street.

“He performed magnificently,” Lukes said. “We were able to see all the spillways in action and the flow along the storm channel.”

Loree Campbell, who has lived on the street for more than 15 years, said she observed the storm channel in action on Sunday.

“It worked perfectly. It was really beautiful,” she said.

The other half of the project, which will close St. George Street between Sixth and Seventh avenues to cars in order to extend the garden along the road, is expected to be completed in December.

Campbell, who joined the community in asking for the rain channel, said she looks forward to completing it.

“It’s absolutely beautiful,” she said.

Charlotte Milne, a flood risk researcher at the University of British Columbia, said projects like the rain channel can help Vancouver manage precipitation as atmospheric rivers become more extreme.

“We’re not just seeing nuisance flooding. It’s fairly regular flooding that’s going to increase in the future,” she said. “Wider implementation of these projects would help a lot.”

She said infrastructure such as rain gardens is often less expensive than traditional stormwater management systems and provides greenery.

They’re not perfect for every situation, she said, adding that they may not be a realistic solution for busy areas, roads where there isn’t enough space to accommodate necessary traffic, or when residents resist changes.

Milne said they may not be able to handle the extreme amounts of precipitation that are more likely to occur with climate change.

Still, she said integrating vegetation and water flow into urban infrastructure would help cities cope with rainfall better than ditches, sewers and culverts.

“We certainly have issues with our stormwater management systems, but a better solution is to continue to implement these natural systems throughout the city,” Milne said. “They may have a greater benefit in the long run.”