People using the Canyonview Trail along the banks of the Campbell River these days will likely notice the big yellow industrial machinery working in the river itself near the old powerhouse.
Not to fear, however, as those machines are run on vegetable products that are safe for the water, and the work they are performing is for the good of the river itself. They are providing much needed help to spawning salmon.
The crews are replacing the gravel in the bed of the river that gets washed out by high water flows. There’s a man-made dam upstream, after all, that keeps new gravel from replacing what gets washed away, so it’s got to be done periodically by man instead of by nature.
Unlike most gravel replacement efforts in the past – and unlike the skyline upstream of this site that dumps buckets of the gravel into the river from above the canyon – this year’s operation is much more extensive.
“We’re kind of changing up the methodology this year,” says Peter Kirillo with Northwest Hydraulic Consultants.
Northwest Hydraulic has been performing the work for many years, but this is Kirillo’s first year overseeing the project.
“In past years we just kind of placed the spawning gravel on the riverbed, but this year, to protect against the possibility of another flood event, we’ve embedded two pads.”
Embedding the gravel sections involves creating a “containment cell” that keeps the sedimentation down while what are essentially large trenches or basins in the river are excavated – they’re about two metres deep – removing the compacted material from the base of the river and, within those basins, replacing it with fresh gravel that’s specifically-sized to be good for salmon spawning.
“The hope is that in high flows, if any gravel does move, those embedded cells will stay put, so we don’t lose the entire volume of gravel that we put in,” Kirillo says.
The operation is funded by the Fish and Wildlife Compensation Program (FWCP), which assigned $188,000 of its $1.9 million in funding this year to the project.
“They’re digging down into the bed of the river itself and replacing the compacted gravel that hasn’t been washed away with a fresh bed of proper stuff,” says Campbell River Salmon Foundation (CRSF) president Martin Buchanan. “The stuff they’re taking out is packed down like cement in there and that’s part of why the good gravel just washes off the surface of it.”
The CRSF, Buchanan says, applies for the grant money from the FWCP, and also monitors the work and measures its success.
“The Campbell is a really short river and it has an incredible run of big chinook,” Buchanan says. “It’s because of the high flows that are in the system, but unfortunately, that’s also what makes it susceptible to the gravel they need to spawn being washed out.”
The other thing that’s new about the project this year is that there are sensors being installed in the gravel so the CRSF can record the gravel movement and be able to tell what effect flow levels have on the gravel, Buchanan says.
“We’re always trying to find better ways to get the gravel to stay where we put it, so the more data we have about when it moves and why it moves, the better we’ll be able to do that. We have to have gravel in here. When it gets washed out, it has to come back in, so we’re trying to find ways for us to have to do that less often, hopefully.”
The work should be completed this week, and by this time next year, the CRSF should know more about whether the new system is an improvement over the old one.
For more information on the project, contact the CRSF directly by email at firstname.lastname@example.org