According to new research by University of British Columbia, clear-cut logging practices are connected to more frequent flooding and extreme flooding events.

The research analyzed data from the Deadman River and Joe Ross Creek watersheds north of Kamloops, which showed the cumulative effects of clear-cutting downstream and the link between the size and state of watersheds and flooding. 

The study showed that when 21 per cent of trees were harvest by clear-cut logging, the average flood size increased by 38 per cent in the Deadman River watershed and 84 per cent in Joe Ross Creek area.

Younes Alila, co-author of the research and hydrology professor at University of British Columbia, said his interest in this particular research was to better understand the clear-cut logging policy across the province.

“My interest lies in understanding and quantifying the effect of the excessive cataloging and clear cut logging policy that has dominated the forestry in British Columbia for several decades,” he said.

Alila said he was surprised to see that his results were “directly opposite to the established quote on quote wisdom and decades of literature.”

“The old experimental design is actually uncontrolled and therefore, non-casual, and that means the outcomes are actually flawed,” he said. “For my experimental design that I have used and the research questions that have guided me are very different from the questions that have guided former hydrologists for decades.”

As for Merritt, which has suffered greatly with the flood back in November of 2021, Alila reminded that the city has two watersheds – the Coldwater River basin and the Nicola River basin – that have suffered human and natural actions that impacted on the flooding.

“These two big basins in the region have been clear-cut logged (from) 30 to 40 per cent,” he said. “And I think it was 20 or 25 per cent of the Coldwater basin was affected by the wildfires.”

Alila said that in a city such as Merritt, which has suffered great damage caused by an intense flooding in 2021, the combination of the wildfire along with clear-cut logging associated with the new climate realities should be a concern to the municipality as well as traditional districts and the B.C. government.

“Usage policies, forest management policies and flood risk management policies should all be designed to make sure that future land use management and forest carbon management are not exacerbating and making the situation worse,” Alila said.

Alila hopes that if natural disasters, such as flooding or extreme flooding, were to occur again in cities like Merritt, communities are better prepared to alert their residents ahead of time.

“I truly hope that we’ve learned from the experience and make sure that the public of British Columbia is actually warned properly and timely to make sure people have time to flee to higher ground and, therefore, be able to save lives.”