Latest news with #YounesAlila
Yahoo
2 days ago
- Climate
- Yahoo
Clearcutting tied to 18-fold increase in flood risk: UBC study
A new study from the University of British Columbia suggests that clearcut logging can make catastrophic floods up to 18 times more frequent. The study, published in the Journal of Hydrology, analyzed long-term data from one of the world's longest-running forest research sites in North Carolina, the Coweeta Hydrologic Laboratory. "We had a good opportunity to test out the effect of the physical characteristics of the landscape on the relationship between logging practices and flooding," Younes Alila, a UBC hydrologist and senior author of the study, told CBC News. Researchers compared two neighbouring watersheds, one facing north, the other south, that were both clear-cut in the late 1950s. They found that clear-cutting in the north-facing watershed, which receives less sunlight and retains more moisture, had a dramatic effect on flood behaviour."The north-facing watershed was super sensitive," Alila said. In that watershed, average flood sizes increased by nearly 50 per cent, while the largest floods were 105 per cent bigger than they were before logging. "Different sides of the mountains will respond differently to logging," Alila explained. He says the north side receives less sunlight, which keeps the soil wetter year-round. When storms arrive, the ground is already moist and can't absorb much water, causing more rain to run off into streams and rivers, resulting in larger floods. In contrast, the south-facing watershed, which loses more moisture due to greater sunlight exposure, saw almost no change in flooding after clear-cutting. WATCH | A clearcut the size of a city in B.C.'s Interior: Alila called the difference "a breakthrough finding," highlighting how landscape factors like the direction a slope faces can reshape a watershed's flood regime. "The point we are trying to make is that we can use the way Mother Nature designed the landscape … to better manage the forest in ways that minimize the risk to hydrology and the risk of floods." Precautionary approach In addition to slope orientation, the hydrology professor emphasized that other landscape characteristics, including whether the terrain is flat or mountainous, contains lakes, wetlands or floodplains, all influence how a watershed responds to logging. "You should not be logging in one part of a watershed without accounting for what's happening elsewhere in the same drainage basin," he said. "Water flows from highlands to lowlands so we need cumulative impact studies before moving ahead with forest development." Alila says the current regulations in B.C. don't require companies to conduct proper watershed-level impact assessments before logging. Researchers say the study's findings are directly relevant to the province, where clear-cut logging remains common and terrain features mirror those of the test site. "Clear-cut logging in B.C. has increased the downstream flood risk rather dramatically," Alila added. He points to the devastating 2018 floods in Grand Forks, B.C. as an example, saying clear-cutting in the Kettle River watershed played a major role. Most flood models that predict the behaviour of floodwaters, assume a simple, predictable relationship between logging and flooding, the UBC professor says. For example, cutting down X per cent of trees, will likely result in Y per cent more water runoff. But the study says after clear-cutting, the risk of extreme and unpredictable floods increases in ways that these basic models can't capture. "This experimental evidence validates our longstanding call for better analysis methods," said Alila. "When we apply proper probabilistic tools to long-term data, we find much stronger and more variable impacts than older models suggest." Jens Wieting, senior policy and science advisor with Sierra Club B.C., said the study underscores the need to reform forestry practices to respond to climate risks. "This study is really demonstrating that we need a precautionary approach," said Wieting. "Clear-cutting can make climate change impacts worse." He said moving away from clear-cutting and toward selective logging — a practice where only certain trees are harvested, leaving the rest of the forest intact — could help reduce flood risk, restore degraded landscapes, and save money in the long run by avoiding climate disaster costs. Province acknowledges research In a statement to CBC News, the B.C. Ministry of Forests said it "appreciates the research being done at UBC" and emphasized that the province continues to invest in water and forest management. "Currently, through allowable cut determinations, the Chief Forester places limits on the rate of cut in each watershed to help provide balance to the many values our forested landscapes provide, including reducing flood risks," the statement reads. The ministry says it's also moving beyond traditional modelling to better understand how changes to forests, water, and climate affect long-term sustainability. That includes promoting practices like selective thinning, fuel management and forest restoration. The province has also introduced Forest Landscape Planning (FLP), which it describes as one of the most effective tools for reducing flood risk at a broader scale. Still, Alila says implementation of old-growth deferrals and other reforms from the province have been slow. "We continue old-growth logging…we've been aggressively clearcut logging for the last many decades so we only have a bit left."
CBC
2 days ago
- Science
- CBC
Clearcutting tied to 18-fold increase in flood risk: UBC study
Social Sharing A new study from the University of British Columbia suggests that clearcut logging can make catastrophic floods up to 18 times more frequent. The study, published in the Journal of Hydrology, analyzed long-term data from one of the world's longest-running forest research sites in North Carolina, the Coweeta Hydrologic Laboratory. "We had a good opportunity to test out the effect of the physical characteristics of the landscape on the relationship between logging practices and flooding," Younes Alila, a UBC hydrologist and senior author of the study, told CBC News. Researchers compared two neighbouring watersheds, one facing north, the other south, that were both clear-cut in the late 1950s. They found that clear-cutting in the north-facing watershed, which receives less sunlight and retains more moisture, had a dramatic effect on flood behaviour. WATCH | What are the lasting effects of B.C.'s logging? What are the lasting effects of B.C.'s logging? 12 months ago "The north-facing watershed was super sensitive," Alila said. In that watershed, average flood sizes increased by nearly 50 per cent, while the largest floods were 105 per cent bigger than they were before logging. "Different sides of the mountains will respond differently to logging," Alila explained. He says the north side receives less sunlight, which keeps the soil wetter year-round. When storms arrive, the ground is already moist and can't absorb much water, causing more rain to run off into streams and rivers, resulting in larger floods. In contrast, the south-facing watershed, which loses more moisture due to greater sunlight exposure, saw almost no change in flooding after clear-cutting. Visit a clearcut the size of a city in B.C.'s Interior 3 years ago Mike Morris is the MLA for Prince George-Mackenzie, a portion of the province that has historically been highly forestry-dependant and heavily logged. He is also a trapper who sees first-hand the impact of that logging on local wildlife, and he wants the rest of the province to know what it looks like. Correction: A previous version of the story included an estimation of the clear cut area that referred to the larger region, not the specific clearcut. Alila called the difference "a breakthrough finding," highlighting how landscape factors like the direction a slope faces can reshape a watershed's flood regime. "The point we are trying to make is that we can use the way Mother Nature designed the landscape … to better manage the forest in ways that minimize the risk to hydrology and the risk of floods." Precautionary approach In addition to slope orientation, the hydrology professor emphasized that other landscape characteristics, including whether the terrain is flat or mountainous, contains lakes, wetlands or floodplains, all influence how a watershed responds to logging. "You should not be logging in one part of a watershed without accounting for what's happening elsewhere in the same drainage basin," he said. "Water flows from highlands to lowlands so we need cumulative impact studies before moving ahead with forest development." Alila says the current regulations in B.C. don't require companies to conduct proper watershed-level impact assessments before logging. Researchers say the study's findings are directly relevant to the province, where clear-cut logging remains common and terrain features mirror those of the test site. "Clear-cut logging in B.C. has increased the downstream flood risk rather dramatically," Alila added. He points to the devastating 2018 floods in Grand Forks, B.C. as an example, saying clear-cutting in the Kettle River watershed played a major role. Most flood models that predict the behaviour of floodwaters, assume a simple, predictable relationship between logging and flooding, the UBC professor says. For example, cutting down X per cent of trees, will likely result in Y per cent more water runoff. But the study says after clear-cutting, the risk of extreme and unpredictable floods increases in ways that these basic models can't capture. "This experimental evidence validates our longstanding call for better analysis methods," said Alila. "When we apply proper probabilistic tools to long-term data, we find much stronger and more variable impacts than older models suggest." Jens Wieting, senior policy and science advisor with Sierra Club B.C., said the study underscores the need to reform forestry practices to respond to climate risks. "This study is really demonstrating that we need a precautionary approach," said Wieting. "Clear-cutting can make climate change impacts worse." He said moving away from clear-cutting and toward selective logging — a practice where only certain trees are harvested, leaving the rest of the forest intact — could help reduce flood risk, restore degraded landscapes, and save money in the long run by avoiding climate disaster costs. Province acknowledges research In a statement to CBC News, the B.C. Ministry of Forests said it "appreciates the research being done at UBC" and emphasized that the province continues to invest in water and forest management. "Currently, through allowable cut determinations, the Chief Forester places limits on the rate of cut in each watershed to help provide balance to the many values our forested landscapes provide, including reducing flood risks," the statement reads. The ministry says it's also moving beyond traditional modelling to better understand how changes to forests, water, and climate affect long-term sustainability. That includes promoting practices like selective thinning, fuel management and forest restoration. The province has also introduced Forest Landscape Planning (FLP), which it describes as one of the most effective tools for reducing flood risk at a broader scale. Still, Alila says implementation of old-growth deferrals and other reforms from the province have been slow.
CBC
12-06-2025
- Climate
- CBC
City of Dawson Creek warns residents to prepare for floods even as wildfires loom
Social Sharing The City of Dawson Creek is warning residents of potential flooding in the coming days, a risk made worse by ongoing drought and wildfires in the region. Environment Canada is forecasting showers starting Wednesday night and lasting through Saturday, while the B.C. River Forecast Centre issued a high streamflow advisory for much of the Interior, with up to 120 millimetres of rain expected in the Peace region in the days ahead. The rainfall comes as the region is entering its third year of extreme drought conditions. The South Peace is at drought Level 4 on a scale that ranges from zero to five and multiple wildfires are burning in the region, forcing some residents from their homes. Drought and wildfires can exacerbate one another and leave the province increasingly vulnerable to severe flooding, according to experts. Drought kills vegetation and leaves soil exposed and hardened, with no root systems to help the soil absorb water when rain does fall, explained Younes Alila, a forestry professor at the University of British Columbia in a 2023 interview. The drier ground can fuel wildfires, which dry things out even further, creating conditions for even more fires and floods. The phenomenon, dubbed "hydroclimate whiplash," has become more frequent and intense, according to recent research, with Canada particularly susceptible. "What we see at the moment is just the beginning," said Andreas Prein of the Institute for Atmospheric and Climate Science. Dawson Creek has been working to strengthen its flood infrastructure since 2016 when rising water levels destroyed roads and forced 60 residents from their homes. In a release, the city says crews are preparing for possible flash flooding and encouraged residents to do the same by preparing emergency kits, moving important documents to safe areas, and clearing gutters. Sandbags are also available at the city yard on 99 Avenue.
