Future-proofing B.C.'s highways
Climate scientists and engineers building relationships
Francis Zwiers
Director, Pacific Climate Impacts Consortium, University of Victoria
In early November 2021, British Columbia was hit with an unprecedented flood that put rail lines out of service, destroyed agriculture in the Fraser Valley and Sumas Prairie, and extensively damaged the highway system running through the province, cutting off Vancouver from the rest of Canada for nearly a month.
I'll never forget the images of rail lines dangling in mid-air because the land they were sitting on had been washed away, or the heroic stories of locals who worked to maintain power to the pumping stations in Sumas Prairie. Without them, there would have been even more extensive damage.
Where I live in Victoria, the main highway on Vancouver Island to the city was washed out. We had to ration gas due to pipelines and transportation systems being shut down, and deliveries to grocery stores were affected.
After the flood, transportation planners and engineers in B.C. had to quickly repair the highway system and figure out how to make it more resilient for the future. As the Director of the Pacific Climate Impacts Consortium (PCIC), I participated in a 'rapid attribution analysis' of the historic event. Our research found that human influence on climate systems increased the odds of this kind of event occurring, and that keeping our transportation systems safe in the future is paramount.
Thankfully, managers and engineers in B.C. continue to ask really challenging questions such as how the intensity of a 200-year precipitation event like this one might impact the roads.
One of those is Jim Barnes, Corporate Engineering Initiatives Manager with the B.C. Ministry of Transportation Infrastructure. I've been working with him for several years to develop a tool for watersheds in B.C. that provides estimates of future extreme streamflows.
When the floods happened, Jim's colleagues went into overdrive!
"To begin with, it was all hands on deck to get the road back up and running, and then we were hiring consulting engineers to design for future conditions," he said. "Highway transportation engineering is about making roads safe to travel on. It's quite eye opening to see what can happen. … Now we realize we need to be more focused about evaluating and upgrading transportation infrastructure proactively."
The challenge with asking engineers and planners to take future climate into account is that there is a lot we simply don't know. We use climate models in our work, which use plausible future emissions scenarios to make projections. You have to pick one of these storylines for what we think might take place. Our job is to give engineers some sense of what those numbers might be and make sure we're conveying uncertainties in an appropriate way.
When Jim and I first started working together, he kept asking for very localized information about extremes and how they might change in the future, and we had to help him understand the scales at which we're able to provide that information. We've both come a long way — I'm now more comfortable providing him the information he needs, and he better understands what information we can and can't provide him with.
"Francis and the team at PCIC are very good at understanding and educating their clients on what the data is, what it's telling us and what the uncertainties are, so you can go away with a full picture of what's being provided," Jim said.
I like talking to Jim because he asks questions from an engineering perspective and I'm trying to explain from a climate science perspective and those aren't necessarily the same. But he's a good learner and I learn a lot from him. That's an important aspect of the relationship — by learning about how they do their jobs, we also learn how to help them pose the question differently so we can provide information that's more reliable.
I've enjoyed working with professionals in transportation and infrastructure in B.C. because they're quite aware that they need to be thinking of future changes in extreme precipitation and streamflow. And working together, we're able to provide more reliable information for infrastructure planning so that if another historic flood occurs, this time, the roads in B.C. will be ready for it.
Find out more about predicting floods in British Columbia:
Islam, S. U., Curry, C. L., Déry, S. J., and Zwiers, F. W.: Quantifying projected changes in runoff variability and flow regimes of the Fraser River Basin, British Columbia, Hydrol. Earth Syst. Sci., 23, 811–828, https://doi.org/10.5194/hess-23-811-2019, 2019.