Rock Wall

In 1998, as part of the Canmore Creek Project, a rock wall was constructed on an erosion site, next to historic Canmore Mines #1 shaft. The rock wall would stop the bank erosion and the loading of coal mine tailings, from entering the Canmore Creek. This would allow the stream bed to clean itself and provide a more healthy natural stream bed.

This is the erosion site where coal mine tailings were getting washed into the stream, annually.

It was determined that a rock armoring of the outside bend in the channel would be the best approach. Due in part to the curvature of the outside bank and for appearance sake, large rocks would seat into the bed and eroding bank efficiently. Rocks for the project site, were lowered into the valley using a cable trolley and basket. It was important not to disturb the natural cover, on the steep slopes of the valley, which were comprised of mainly mine tailings and very unstable.

My crew and I constructed the rock wall, with planted willow cuttings that had been pre-grown for this particular project. We also carried out in-stream fish habitat enhancement work along the creek. You can see some nice boulder work, just out from the rock wall.

If you look behind the right shoulder of Eric Lardizable, in the yellow jacket, you will see part of the mining structure at the historic site. The timbers are across the creek channel in the trees. Duncan McColl is on the right in the photo. Duncan was my main guy (foreman) for construction. I was lucky to have such a good crew for that particular stream restoration project. Duncan had been with me from the start, which was a year earlier, on Canmore Creek.

This is a photo of the rock wall, from a downstream perspective, one year later. You can see the willows are now growing good, as hoped. The channel and stream bank will look very natural over time.

On Canmore Creek, there is a natural shale and possible coal seam, right at the big falls on the lower reach of the creek. Even the smaller lower falls is comprised of shale, so there is a lot of shale in the stream bed. However, areas where the current flows faster, show gravel, cobble and boulders beneath the shale. Trout can actually spawn in shale, but it is very hard on the fishes tail. A trout can wear part of the tail fin off, but fanning a nest in sharper shale beds. However, the success of incubation of trout eggs in shale, must be high enough to support a population of trout on some streams.

This is a photo of the same rock wall, nine years after construction. Someone has built some small rock dams both upstream on the wall and just downstream. This playing in the creek is typical, when the project site is close to any residential homes. The willows are now growing well and the rock-wall looks totally natural.

At least, both the log wall site and the rock wall site are no longer contributors to the high volumes of tailings that enter the creek. The stream does support a population of brook trout and I even captured brown trout while trout trapping the section between the big falls and lower falls. I later learned that some residents once netted big brown trout below the falls and helped them out by carrying the trout above the falls. This information was given to me by several nearby residents. So whether there still are brown trout in that reach of the creek, it is yet to be determined, by me personally.

This is another view of the rock wall site. It looks pretty natural now. No more loose mine tailings visible, other than where heavy traffic of people visiting the old mine shaft, hidden behind the trees and blocked off, for good reason. There is a lingering odor of gases coming out of the old mine. Not a good place to get too close to.

The last time that I visited the rock wall site, the upper part of the rock wall had already grown in with sod, right down to the water’s edge, covering the rocks. There were also spruce trees, along with the planted willows, which are now growing on top of the upper part of the wall. On my next trip up to the area, I will take another photo for some comparison. In the first decade of 2000, there were trout in the creek on every trip I made up to inspect our enhancement work.

Leave a Reply

Your email address will not be published. Required fields are marked *

* Copy This Password *

* Type Or Paste Password Here *