A large trolley drops huge piles of gravel into the canyon by Elk Fall Suspension Bridge. The nearby John Hart Dam blocks the natural flows of gravel used by salmon to make their nests. Photo by David Gordon Koch/Campbell River Mirror

VIDEO: Tons of gravel dumped in river for salmon spawning grounds

John Hart Dam blocks gravel needed for chinook

Biologists from the BC Conservation Foundation (BCCF) are doing some heavy lifting for salmon reproduction. They’re dumping about 500 tons of gravel from the heights of the Elk Falls Canyon into the Campbell River.

The John Hart Dam blocks the normal flows of gravel that salmon use to build their nests, explained Jeramy Damborg, senior project biologist with the BCCF.

“We’re trying to help out a bit by adding gravel artificially,” he said while monitoring the process from Elk Falls Suspension Bridge, 64 metres above the rushing river below.

That process involves a cable called a “skyline” that runs across the canyon, carrying a large bucket that holds about 1,500 pounds of gravel, one full scoop of rocks from a small front-end loader.

“We press a button, the bucket tips and the gravel falls to the canyon,” Damborg explained. The rocks have been pre-washed so silt doesn’t “dirty up the river,” he added.

It takes several seconds for the rocks to fall to the river below, where they resound loudly over the thundering waters.

The project, which is funded by BC Hydro through its Fish and Wildlife Compensation Program, is meant to offset the effects of the John Hart Dam, which causes gravel to pile up in the John Hart Lake, explained Damborg.

“There’s no new gravel entering the system above the Quinsam River,” he said.

That makes the river less hospitable for salmon when they swim upstream to spawn. The fish normally lay their eggs in nests among pieces of stone, he explained.

During the winter, medium or high flows of water passing through the dam flush away the gravel, so it needs to be replenished annually, said Damborg.

This is the fourth consecutive year that gravel has been dumped into the river using the skyline system. Previously, the gravel was delivered using heavy-lift helicopters, an arrangement that had been in place since the 1990s, said Damborg.

Prior to that, nothing compensated for the lack of gravel caused by the dam, which was opened in 1947. That negatively affected the fish.

Even now, there remains a gravel shortage for chinook salmon.

“It’s one of the main concerns for the Campbell, is chinook gravel,” he said.

The dumping of the gravel usually takes about five to seven days to complete. It’s a sight to behold, and hikers have an excellent view from the Elk Falls Suspension Bridge.

@davidgordonkoch
david.koch@campbellrivermirror.com

Like us on Facebook and follow us on Twitter