Innovation Fall 2024

Probabilistic method’s value in the watershed Dr. Martin Carver, P.Eng., P.Geo., a hydrologist and geomorphologist and principal at Aqua Environmental Associates, says deterministic methods shine at the site level, where there is some control over the variables that affect the outcome associated with runoff. However, at the watershed level, he says the probabilistic method has more value. “Watersheds are pretty complicated even when they’re pristine and intact. Now that they’re heavily disturbed, it’s beyond the reach of determinism to manage this,” he says. “Flood generation is fundamentally probabilistic. We can describe the likelihood of something like a flood happening, but we cannot tell you what

loss of forest cover in BC, which is quite a long list. “Just think of the salvage logging associated with the pine beetle epidemic and think of the years of wildfires — last year was the biggest, and in all likelihood we will continue seeing record-breaking wildfire years,” he says. “To really home in on the high-risk areas, it’s important to also identify locations in BC that are vulnerable to increases in flood risk due to climate change and then we would link these together.” Carver was a contributor to the Professional Practice Guidelines titled Watershed Assessment and Management of Hydrologic and Geomorphic Risk in the Forest

will happen next. That’s really at the heart of this. No one knows when the next flood’s going to occur, how severe it’s going to be, and what the extent of the flood’s going to be. We’re simplifying the behaviour of the system way too much.” He says devastation from increased flooding in BC shows that determinism is not equipped to fully analyze the changes that are happening now. Carver says the probabilistic framework is well established in the wider field of hydrologic and climate change science and is a common basis for analysis. Loss of forests impacts flooding Carver advises a step forward is identifying where there’s extensive

MMCD Accepted, BC MoTI Recognized, AREMA Approved

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Fall 2024

Innovation