Barrhaven subdivision formerly in floodplain will stay dry, developer pledges

A new subdivision in Barrhaven that got the go-ahead at city hallthis week used to fallwithin the edges of the Jock Riverfloodplain, but the developer says it won't bea problem keeping homes high and dry.

Caivanis working withthe Rideau Valley Conservation Authority tomove land around and getproperties in its new Barrhaven Conservancy developmenton the right side of the flood line.

It's no longer in the floodplain. We don't allow development in the floodplain.- Don Herweyer, City of Ottawa

The file received no discussion at Thursday's planning committee meeting, and Barrhaven Coun. Jan Harder, the committee's chair, has no concerns.

"[The conservation authority]would not have allowed it if it was a problem. There's a science to figuring this stuff out," she said.

DonHerweyer, the City of Ottawa's manager for development reviews in the south end, underscored that sentiment after planning committee approved the zoning.

"It's no longer in the floodplain," he said. "We don't allow development in the floodplain."

Moving land around

A small portion of the lots,however, used to see the flood line run through them.

That's a theoretical line theRideau Valley Conservation Authority modelled in 2005to show areas that stoodaone-in-a-hundred-year chance of flooding.

Development is prohibited inside such lines.

Caivanreceiveda permit from the conservation authority to gradethose lots to a higher levelbasements will be poured one foot abovethe flood elevationand will have to grade lower elsewhere, in order to createextra space for water to flow.

Protected at 'high standard'

At a time when the City of Ottawa is in a state of emergency over rising flood levels, attention has turned to where homes have been built or could or should be rebuilt.

But Frank Cairo,Caivan'sCEO, says buyersshould have "no concern at all".

Present-day engineering and planning takes into accountflood elevations, sump pumps, andstormwater management drainage, said Cairo unlikelow-lying neighbourhoods built decades ago.

• In Pointe-Gatineau, residents try to prevent repeat of 2017 floods

"We protect these units at a very, very high standard," Cairo said. "And that's why you don't see flooding in new residential areas during these significant rain events."

Shifting floodplain lines

Cairo walked through his Barrhaven property Friday and saideven with the heavy rains, there's no water near the build site.

"Much of the area that we call floodplain has never flooded," he said, addinghe believes some of the mapping overstates the flood risk near the Jock River.

The city agrees and has noted someareas of Caivan's Conservancy property could open for developmentif future mapping of the Jock River changes flood lines.

That happened in nearby Kars, when recent mapping saw the Rideau River's floodplain reduced slightly. Technology has made flood mapping more accurate and cheaper in recent years, and thanks to funding from the city and the federal government, the three Ottawa conservation areas have made a push to map local waterways.

• Flood-monitoring groups absorb cut from province
• Want to know if you live in a high-risk flood area? 'Good luck,' says expert

As for the Jock River, that same floodplain that triggersregulatory steps is also greenspace and a major selling point for home buyers, Cairo says.

'Signature piece'

Harder called Caivana "genius" for how considering the development's relationship toa futurelinear park along the river.

"I'd say this is their signature piece in the city. Andthey own a lot of land," she said. "I'm really [excited] about what it's going to look like."

Caivan plans to start construction in the coming monthsafter the zoning receives full council's approval and some other conservation authority permits.