A Case Study on Restoring Habitat Connectivity in the Wildhorse River
Author: Curtis Abney, MSc., RPBio
The Wildhorse River meanders through the picturesque heritage town of Fort Steele, nestled in the Rocky Mountain Trench of southeastern BC. In the mid-19th century, the town garnered a reputation for its goldfields, which drove thousands of visitors to the banks of the Wildhorse in search of those precious gold nuggets. Over the years, what started as a pan-in-hand shoreside operation eventually evolved into full-on cannons blasting water into the hillsides to dislodge gold from the canyon walls. This process, known as hydraulic mining, led to the deposition of vast amounts of cobbles and fine gravels into the river system. During heavy freshet (spring flush) events, these materials would mobilize downstream on route to the Kootenay River confluence.
View downslope of a hillside that was hydraulic mined –>
As the decades passed, more and more of this rock was deposited along the river bed, gradually raising the elevation near its confluence with the Kootenay River. This elevation change eventually prevented the river from reaching its destination during low-flow events. Now, almost annually, we see this event take place where fish become trapped upstream, migration and spawning cycles of various sportfish are interrupted, and mass fish-stranding events occur. The Wildhorse had effectively become an ecological trap to fish.
Aerial photograph showing the disconnected Wildhorse River on September 14, 2023. Photo courtesy of G. Courtice 2023
Despite this connectivity issue, the Wildhorse River is an extremely productive system that supports important populations of Bull trout, Westslope cutthroat, and Kokanee. These fisheries not only provide a strong economic benefit to the province, but the river and its fisheries hold an intrinsic, cultural value to First Nations, and an ecological value to the greater Kootenay watershed. In light of this, members of the provincial Fisheries Guardian team put out a request for help. Cabin saw the request and knew we couldn’t do it alone. So, what did we do? We joined forces with a strong engineering team from Applied Ecohydraulics and McElhanney and received incredible technical support from fisheries biologists from Ktunaxa Nation, Shuswap Band, DFO, and the province. We even had the Ministry of Transportation involved in the project! All of these players came together to identify the problem and come up with an action plan to solve it. When working in such a delicate, yet dynamic system, our team relied on the collaboration with local knowledge keepers and a robust team of professionals to make sure we could identify a solution that would be sustaining, and one we could all get behind.
Introducing Operation flow-split. The vast majority of fish stranding events were happening in what we refer to as the “east channel”. However, there was a perfectly intact “west channel” that was shorter, steeper, and offered better fish habitat than the east. So, why not try to encourage the river to use the west channel instead of the east when water is low? A flow-split structure could do the trick! Of course, there was careful modelling of the entire system done beforehand to suggest that our theory was practicable. This modelling was paired with thorough engineering to design a structure that was built to last, without interrupting peak flows, putting adjacent infrastructure at risk, or impeding fish movement. After a few presentations and feedback from our technical advisory committee, we had our plan.
In October of 2024, the aforementioned project players convened in Fort Steele and launched construction. A little bit of preparation was needed in the west channel to prepare it for year-round flow, but the majority of the work was completed in the mainstem of the river just upstream. Here we built a ~55m long trench across the river, backfilled it with angular riprap and native cobbles, and regraded the west channel entrance – all while maintaining flows downstream and keeping our construction areas fish-free. The days were long, and there was a lot of field-fitting to do, but our amazing construction crew managed to pull off the project in just five days!
Downstream view of the trench building in Wildhorse River. Fish were safely salvaged from the work zone before construction.
In May of 2025, we were able to confirm that the west channel was flowing – the first indication that our plan was working! Now we wait until the end of summer to track the river’s behaviour during low flows. Our initial observations indicate that our flow-split structure will work as planned, but only time will be able to prove us right. One thing is for certain: we will not rest until the Wildhorse and Kootenay Rivers are permanently connected, and our precious salmonids can migrate without fear of being trapped.
The finished flow-split structure, hardly discernible beneath the flow of the Wildhorse River (October 2024)
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