By Roy L Hales
Two weeks ago, the Ministry of Transportation and Infrastructure closed a small segment of Whaletown Road on Cortes Island. The impact on the local community is minimal. However British Columbia’s threatened fish stocks greatly benefit from projects like replacing the culvert at Basil Creek.
The Problem With About 140,000 Culverts
“The province estimates there is about 140,000 culverts that are barriers to upstream fish passage in B.C. alone … A lot of our species that are of value, like pacific salmon, require upstream migration through culverts to get to their spawning areas. If a culvert blocks them it can basically eliminate a lot of useful habitat. In some cases it has caused extirpation, or local extinction, of local fish populations,” explains Sean Wong, senior biologist with the Ministry’s Environmental Management branch.
That’s what happened to the Chum and Pink Salmon that were unable to get through the culvert at Basil Creek in 2015.
“They all died right at the front of that culvert. There isn’t enough of a pool at the front of the outlet for them to gain some speed and jump into that culvert. There isn’t enough water in the culvert to get them through. They were just sitting desperately waiting for some water and a predator nailed them all. I don’t know if it was a mink or what, but you could look at the caucuses later and see that nine out of ten of them had not spawned,” Cortes Island Streamkeeper Cec Robinson told me in a previous interview.
Replacing the Culvert at Basil Creek
“We are replacing an old rusted out culvert with this new open bottom one. It is really going to help the fish habitat because there is gravel lining on the bottom instead of steel. So the fish won’t notice the difference as they are swimming up. And the old culvert had a drop of about a foot and a half off one end, so the fish were having trouble getting up on top of it,” says Nick Richardson, from Landtec industries.
Wong explained that the open bottom design utilized for this project: ” … is a key difference in design that much better enables fish passage, plus provides incremental habitat within the crossing … Any time you enclose a stream with an extremely artificial constriction – like a metal culvert or a plastic culvert or a concrete culvert, that narrows the stream, accelerates the flows and provides an unnatural bottom – it is problematic. The big jump to an open bottom is not only effective not only in providing fish passage and enabling natural processes.”
The Vegetated Walls
The vegetated walls, surrounding the culvert on either end, are another innovative feature of this project.
“Those cuttings will overhang, above the stream, creating good shade; keeping the stream cool [which is good for the fish] … as well structurally they help to hold everything together with their rooting system… So that when there are big rain events, you are not going to have all that soil and extra stuff flushing away from the culvert, ” said Emily Grub, of the Central West Coast Forest Society.
This week the crew will be doing some work downstream, to improve the spawning ground.
Kiara Robertson, an environmental technologist who has worked with Wong on five previous projects, says she has seen fish returning to their historic spawning streams.
“I’ve seen the fish using the projects that we’ve worked on. Obviously your not going to see improvements on a larger scale for a long period of time … Over time we can definitely get things back on track to the way that they should be.”
After they are through, the crew will move on to Whaletown creek and after that to two culverts on Quadra Island.
The article above consists of a few highlights lifted directly from the podcast, which you can listen to above.
Some of the other people and issues in the podcast:
- examples of where culverts have prevented fish from returning to spawning grounds, and how the fish have returned to their ancient spawning grounds when this problem is rectified.
- More detailed examples of almost everything mentioned in the written article above.
- Other ways in which human actions have damaged spawning grounds.
- interviews with: Kiya Porteous, Laurie Mathieu & Brent Smith (as well as everyone mentioned in the article above).
- The principle challenge for this program is funding and how organizations like the Friends of Cortes Island and Pacific Salmon Foundation helped bring it to Basil Creek
Top Photo Credit: Replacing the culvert on Basil Creek