Watershed science
Alila and Carver say the province has no set prescriptions for how exactly watershed risk assessments should be conducted ahead of forest harvesting
The results of watershed assessments aren’t typically shared with the public in B.C., Carver notes. They belong to the companies that produce or commission them.
Carver did not specifically review the Mount Elphinstone watershed assessment or Alila’s review of the study before speaking with The Canadian Press.
But he says a probabilistic approach is necessary to assess the risk of post-logging extremes once a watershed reaches a certain size or complexity.
“When our systems get larger, both in terms of the size of the watershed, or the events get larger … you cannot do that analysis deterministically anymore,” he says.
“You no longer know how the complex of processes are interacting, overlaying, competing, compensating, right? All of those things are happening and yielding an outcome. But we do know from the frequency analysis that as remarkable as nature always is to us, a pattern emerges in the frequency distribution.”
Alila and Carver say the B.C. government has no set prescriptions for how exactly watershed risk assessments should be conducted ahead of forest harvesting.
Instead, the province has been using a system known as professional reliance to manage forestry and other resources industries since the early 2000s. It’s up to engineers, geoscientists and other professionals to decide how to assess risks.
Carver is one of the primary authors of the joint professional guidelines that Polar Geoscience says it adhered to with its Mount Elphinstone study.
He says the guidelines are not prescriptive when it comes to scientific methods.
“It’s like a community of practice out there, and we’re all meeting certain scientific expectations, and if you’re going to depart from that, then explain yourself.”
In its response last fall, Polar says Alila should approach the professional groups if he believes the guidelines require revision. It suggests that Alila offer “practical, defensible and cost-effective solutions to implementing the concepts he promotes.”
Carver says he believes there’s a growing recognition of the differences between deterministic and probabilistic approaches among professionals in B.C.
But he says the province is “lagging behind” when it comes to incorporating the science.
And as climate extremes become more frequent and severe, he says, assessing the risks incorrectly could lead to greater damages and losses of life. “If we continue to mischaracterize [extremes], and if we continue to manage the forest and disturbance levels as if we were doing fine, we’re going to take the system further and further out of anything that is protective.”