VANCOUVER -- Construction of a $176 million permanent fishway to help salmon populations get past the Big Bar landslide will be delayed, according to the Department of Fisheries and Oceans Canada.

The landslide in B.C.’s Southern Interior is believed to have happened in late October or early November 2018, but it wasn't discovered until June 2019.

The incident created a five-metre waterfall that's preventing many fish from swimming upstream to spawn. Work on site has been ongoing ever since.

In a technical briefing Wednesday morning, landslide response director Gwil Roberts said there had been delays at the site during the winter. Extreme cold weather meant crews had less time to prepare for installation of the permanent system.

“Then we had a freeze-thaw period where we had very quick changes, -10 degrees celsius overnight and then +10 during the day,” Roberts said. “That created some instability on the slope where teams were preparing the bed for the fishway.”

As a result, Roberts said the fishway “will not be installed by May 2022 as planned.”

The pricey project was announced in December, with the department saying work would “begin immediately to take advantage of low river levels in winter.”

Fisheries officials say they expect thousands of migrating salmon to still be able to pass through the site this year thanks to temporary structural changes, including a “nature-like” fishway.

Michael Crowe with Fisheries and Oceans Canada said the fishway is “performing as hoped" and chinook salmon are able to make it through the slide zone without many problems. Though early arrivals of sockeye salmon remain vulnerable in high waters.

Work will also continue this year to transport fish via truck around the slide zone, while the tube system, or “salmon cannon” will not be used. Roberts said it was not technically feasible.

“When we did a cost benefit analysis of that system, it did not make sense so we decided to focus on our truck and transport system this year,” he said.