B.C. village not on the hook after flood causes significant damage to woman's home

Workers clean up after flash flooding in Cache Creek, B.C., on Monday, May 25, 2015. THE CANADIAN PRESS/Devon Lindsay

A B.C. woman's attempt to sue her village for extensive flood damage to her home was shot down in Supreme Court this month.

Charlene Milward told the court earlier this year her home and personal property were severely damaged during a significant rainstorm in Cache Creek on May 23, 2015. Milward wasn't home when the storm hit, but she returned the following day and saw the damage.

Justice Andrew Mayer's decision, which was published last week, explained the two parties didn't dispute that a culvert was "overwhelmed by water and debris" during the storm, which led to "water and sediment escaping the Lopez Creek channel and entering and damaging" Milward's property.

But Milward alleged Cache Creek was negligent, claiming the flood wouldn't have happened if the village had replaced the culvert with a larger one, or multiple ones.

Upgrade project omits culverts

Mayer's decision explained the overwhelmed culvert had been in place since the 1960s.

"Lopez Creek runs from the surrounding hillsides, through private land adjacent to Ms. Milward's property and crosses underneath Stage Road through the culvert. It is an ephemeral creek—meaning it only carries water periodically, during periods of heavy rain or a freshet—and drains a catchment area of approximately 10 square kilometers," Mayer wrote.

"Starting in 2001, Cache Creek started planning for an upgrade project along Stage Road, which involved road resurfacing, upgrading storm drains along the roadside and installing new sidewalks."

That upgrade project was designed by Stantec Consulting, an engineering firm. Before the project began, the village's chief administrative officer asked Stantec to provide an assessment of culverts under Stage Road, following a query from a village councillor.

In 2003, Stantec said the culvert was "in good condition" and could handle peak water flow of 3.9 cubic metres per second. But it did say that two larger culverts would be necessary if there was a "worst-case scenario storm," which would require peak water flow capacity of 10.2 cubic metres per second.

"The Stantec letter did not specify what storm risk that Cache Creek should consider," Mayer's decision says. "Nor is it clear from the Stantec letter whether Stantec was recommending that the Stantec culverts be installed as part of the upgrade project."

Cache Creek's CAO looked into the matter further, Mayer wrote, and the village decided not to install new culverts.

"This was because there was no history of flooding at this location or history of water flow within Lopez Creek, the cost of upgrading the culvert (estimated at $50,000) was too high, and revising the upgrade project could result in project delays," Mayer explained, adding the upgrade project was finished around 2005.

Storm 'so severe'

In response to Milward's allegations of negligence, Cache Creek argued that even if it had replaced the culvert in the early 2000s, the 2015 storm "was so severe that the sediment that washed down Lopez Creek would have nonetheless blocked the Culvert and caused the flood."

Mayer said it was Milward's burden to prove that the larger culverts would've made a difference and protected her property.

Milward used an expert report prepared by Brian LaCas, a hydrotechnical engineer. In his report, LaCas said he couldn't estimate how much rain fell in the catchment area that feeds Lopez Creek because of a lack of data. In his opinion, LaCas said the culvert had the capacity to handle water volumes of a one-in-10-year flood. Based on guidelines from B.C.'s Ministry of Transportation, however, LaCas argued Cache Creek should've installed a culvert that could handle a one-in-200-year flood.

But LaCas gave his opinion that Stantec's proposed culverts wouldn't have been able to handle the peak water flow on the day of the flood either, saying sedimentation would've blocked or partially blocked the culverts.

"Mr. LaCas concluded that an 'adequately sized' concrete box culvert could have been installed to mitigate water and debris that flowed over and onto Ms. Milward’s property on May 23, 2015," Mayer wrote. "He did not explain what size concrete box culvert would be required or whether the flood would have been avoided if such a culvert was installed."

Meanwhile, Cache Creek submitted expert opinion from Jamie Stirling, a geoscientist. Stirling couldn't definitively say whether a larger culvert would have prevented damage.

"The only thing that can be said with certainty is that a much larger culvert … would have been more able to safely convey the peak flow of May 23, 2015. However there is no guarantee that damage to property would have been avoided entirely," Stirling's report said. "It is important to understand that I don't know that a larger culvert would have safely conveyed the storm."

'Key fact' missing

Mayer said the amount of rain that fell on the day of the flood is a "key fact in this case." However, only opinion evidence of how much rain fall was submitted due to a lack of data.

"Even if Cache Creek had installed the Stantec culverts, or an even larger culvert, as Ms. Milward says they should have done, would it have made any difference? I am unable to say if it would not have," Mayer wrote.

Mayer went on to say he was unable to give weight to LaCas's expert opinion, saying his estimates of peak water flow haven't been proven.

"It is clear from the photographs and factual observations of engineers tendered at trial that during the storm, a large amount of sediment and rock were scoured from Lopez Creek and at some point, blocked the culvert. It has not been shown whether this would not have occurred if a larger culvert had been installed," Mayer wrote.

"I conclude that Ms. Milward has not proven, as is her burden, that Cache Creek’s decision not to install larger culverts at the intersection of Lopez Creek and Stage Road caused the flood."