Researchers in BC to map landslides in Fraser River, help protect salmon

VANCOUVER — British Columbia geoscientists return to the scene of a massive landslide on the Fraser River to map its effects and assess the risk of future slides on salmon.

VANCOUVER — British Columbia geoscientists return to the scene of a massive landslide on the Fraser River to map its effects and assess the risk of future slides on salmon.

The landslide in November 2018 sent a five-meter waterfall into the river north of Lillooet, making it nearly impossible for migrating salmon to reach their spawning grounds.

Jeremy Venditti, the project’s lead researcher, said his team of scientists will map the topography in the area using a laser to identify between 20 and 100 possible slip spots along the river.

“We’re looking for sites that could pose some sort of imminent threat, or where an imminent shift could take place, and then we’ll also identify locations where they could happen,” he said in an interview on Thursday.

Venditti said his team had set up a field site in the same location as the 2018 slide nearly a decade earlier so they can compare their findings with 2009 data to see how the slide has changed the river and how they can better predict it. events.

“We felt that, as geoscientists, it was time for us to start investigating where in the Fraser other landslides have occurred in the past, as well as (where they will) occur in the future, and the effects they have on the flow. in the river, fish migration and the genetics of Fraser salmon, which we think have probably been hit by landslides a number of times now.”

Venditti said they will share the information with the Fisheries Department and First Nations communities so they can prepare for potential slides and make plans to protect the salmon.

He said potential mitigation could be technical solutions, such as building fishing trails that could help salmon get past blocked passageways.

The fisheries department said 85,000 cubic meters of rock fell into the river, preventing many salmon races from migrating.

After the remote slide was discovered, the fish was transported around the site by helicopters, trucks and a so-called salmon cannon until a fish ladder was built, though the department said in July it was still looking for a more permanent solution.

The department has said the shift is a major factor in some of the worst salmon yields on record in the Fraser River.

This report from The Canadian Press was first published on May 12, 2022.

The Canadian Press

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