Alternative fish passage systems at the Big Bar landslide response in British Columbia

The vision that we had was to make sure that we’d completed as much winter work activity, construction work on the river itself.

And seeing how those fish can migrate past this point naturally, as a result of those efforts.

We needed to make sure we also had contingencies in place, if we were not successful doing that.

We had to look at a number of avenues to assist fish through the site with the expectation that even with all the rock removal, not enough would be able to be removed to allow fish to migrate freely.

Therefore, we came up with three primary strategies to help fish through the site.

One was to create a "nature-like" fishway.

We also provided for alternative fish passage systems through mechanical assistance.

One was through a pneumatic pump system, the other system was to capture fish, transport them by truck and release them back into the Fraser.

The "nature-like" fishway was constructed to try to simulate natural riverbank conditions.

We had the primary contractor strategically place large amounts of boulder, to create the right hydraulic effects that would create steps and pools, that the fish could take advantage of to move through the slide area.

So essentially, we were creating almost like a ladder effect, out of natural bedrock material. 

The fish have not been handled, they do not have to be delayed and they essentially are just volitionally making their way past the slide.

We did understand however that there's a certain point as water got too deep that those hydraulic benefits would be lost.

So what we designed was a system that had layers, where one system of alternative fish passage was no longer effective there would be a backup system to that.

The Whooshh system is a fish passage that relies on air pressure to transport fish.

We had to devise a system to have fish volitionally exit the Fraser River and come to the Whooshh, and we did that by creating a fish ladder made out of lock blocks.

It's a channel with a number of baffles in it, each one a little higher than the other and allowing fish to get out of the river.

Then they volitionally enter what's called a scanner box.

Then they are pushed via air through a tube until they're discharged at the terminal end and then they can continue with their upstream migration.

The fish wheel was called to Big Bar during the truck and transport.

The fish wheel could start fishing before the Whooshh could start working or before the fishway could actually start working cause the water was too high it wouldn’t work properly.

We would actually take as many as we could off the wheel, transport them across the river into the trucks on Beach One and drive them over to French Bar.

And they built a nice little road and a ramp, and we just opened the hatchback up, and they would just slide down into their freedom.

And then they would just swim north. So, we did that many times.

Once the Whooshh started working 100%, once the fish started making it through themselves, it wasn't needed for us to do that, but we were there to help just in case, and it's a good thing we were there because we put a lot of fish over the mountain to their freedom in truck and transport.

Salmon is really important to all the communities.

So as long as we are doing anything we can to save the runs, then maybe our grandkids and great grandkids will be able to have some fish on their plates when they grow up.