Three Sisters Creek – One Year After the Flood

Rainfall WarningThe rainfall warning in effect for a large part of southern Alberta over the past couple of days prompted me to spend some time reflecting on the consequences of last year’s flood, particularly in our part-time home town of Canmore.

Some of the most dramatic images from the June 2013 flood were taken at Cougar Creek in Canmore; in case you missed it, this May 2014 clip from Global Calgary includes video from the peak of the flood plus a good overview of the Cougar Creek flood mitigation measures put in place over the last eleven months.

Cougar Creek is just one of several creeks severely affected last June. We’ve been keeping a particularly close eye on the post-flood changes along Three Sisters Creek, at the eastern edge of Canmore. This YouTube video was filmed at Three Sisters Creek during last June’s torrential rains. After a creek-jumping, rock-hopping exploration of the post-flood Three Sisters Creek, we posted several before/after photos in this blog post.

As of early June 2014, the short-term flood mitigation work along Three Sisters Creek appears to be complete. Last summer, volunteers constructed new bridges over the creek to get the west end of the Highline Trail re-opened as soon as possible. Crews have reinforced the culverts where the creek crosses under the Three Sisters Parkway. And Mother Nature is doing her part, too. While the Yellow Mountain Avens that used to grow along the creek will take a few years to re-establish, there are plenty of Calypso orchids blooming along the Highline Trail near the creek.

As we join many Albertans keeping a close eye on the weather this week, we’re thankful for all the hard work that’s gone into preparing Canmore’s creeks for the next round of snow melt and spring rain…

Three Sisters Creek rose to just below the bridge deck last June and the tremendous volume of water and flood debris washed out the two culverts that were in place under the bridge. Recent flood mitigation work installed concrete mats immediately upstream and downstream of the bridge, along with some larger boulders downstream of the mats. The channel has been significantly widened and straightened here and crews worked downstream of this point to clear all the culvert pipes and downed trees out of the creek channel.
The water hazard on the unfinished Three Sisters Creek golf course has been re-excavated. What was a basically a mud puddle after last year’s flood is once again a large turquoise pond.
Upstream of the water hazard, the creek channel is much wider and straighter than it was prior to last June’s flood. One stretch of he clay and gravel berm on the left used to be a meadow of wildflowers, washed away during the June 2013 flood.
Further upstream, in Bow Valley Wildland Provincial Park, there’s an old dam constructed during Canmore’s coal mining era. Part of the dam broke away in the spring of 2012. During the June 2013 flood, enough of the dam broke away that there’s no longer a reservoir upstream of the dam site. And since then, even more of the dam has disappeared, so there are now two or three waterfalls coming down from the remnants of the dam.
Upstream of the dam there are lots of small steps along the creek, many of them created as boulders tumbled along and eventually came to rest during the June 2013 flood. Here, a rock with a thin covering a soil sprouts a baby evergreen tree and maybe even a flower or two that will bloom this summer.
We didn’t get any further than the “big falls” on the creek, which are maybe 600 meters or so upstream of the dam. During last year’s flood, the falls shifted to the right, as you can see in this photograph made by Mr. GeoK.
Here are a couple of the hundreds of Fairy Slippers we saw blooming near Three Sisters Creek a little earlier this month. For me, they symbolize the fact that Mother Nature has her own remediation plan, as well as the spirit and strength of the Canmore community.

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