Enhancing the downstream riffle raised the water level of the pool to improve fish passage.
Reconnecting Caton Creek-A few years ago during our annual Fish Rescue, one of our volunteers was surprised that we were rescuing all of the fish from a draining irrigation canal. In particular, he said, “this isn’t Suckers Unlimited, it’s Trout Unlimited” and asked why would we rescue suckers. This was a good opportunity for our staff to mention that our interest is in the fish community, not just trout. Although they aren’t considered a sport species outside of the micro-fishing community, minnows and suckers play an important role in the ecosystem.
In fact, while many of our habitat rehabilitation projects are indeed focused on native and naturalized trout and trout habitat, we recently completed a project in southwestern Saskatchewan where the target species is the humble Plains Sucker (Pantosteus jordani).
The Cypress Hills of Southwestern Saskatchewan are a unique geographical feature in the prairies. Untouched by the last glaciation, the highest elevation in the Cypress Hills is actually slightly greater than that of the Banff townsite. The region receives more precipitation than the surrounding prairie. Precipitation soaks into the ground emerging as the springs that feed coldwater streams which flow into the Frenchman River. These streams are cold enough to support trout which have been stocked in the area for recreational fishing opportunities. They also provide habitat for Plains Sucker (formerly known as Mountain Sucker). The Milk River population of Plains Sucker (which includes the Milk River in southeastern Alberta and the Battle and Frenchman River watersheds in southwestern Saskatchewan) were recently listed on the federal Species at Risk Act as “Threatened”. This population faces a variety of threats including water management and irrigation, agricultural and livestock practices, and habitat fragmentation.
During construction, water quality was monitored to ensure too much sediment was not released downstream.
As part of our national Reconnecting Canada initiative, TUC is working with partners to improve conditions at stream crossings (like culverts) where fish passage barriers exist. Man-made barriers can completely or partially block fish passage. A research document published by Fisheries and Oceans Canada suggested a hanging culvert along Caton Creek was one such barrier for Plains Suckers. While culverts are commonly used to convey streams under roads, over time (or where poorly installed or undersized), scour at the outlet can cause them to become perched, blocking upstream fish movement.
Sometimes it is feasible to replace problem culverts with a larger or embedded pipe or install open-bottom structures such as arches or bridges. However, sometimes there are feasibility or cost barriers to these large-scale projects. Alternatives to full replacement can include modifications to the stream or culvert to improve connectivity. This was the approach taken to improve connectivity at Caton Creek.
In late 2018, TUC worked with a local construction contractor to augment a riffle downstream of the culvert outlet to raise the water level in the outlet pool by about 20 cm. This is enough to reduce the hang height of the culvert making it easier for fish to travel upstream.
In the coming years, TUC will be back to evaluate the project and explore other opportunities to help recover Plains Sucker in this unique part of the world.
Thanks to Environment and Climate Change Canada’s Habitat Stewardship Program for Species at Risk and Saskatchewan Wildlife Federation and Fish and Wildlife Development Fund for supporting this project. The design was completed by Matrix Solutions and construction was completed by Davis Excavating. Thanks also to TransCanada Corporation for supporting this project as part of our national Reconnecting Canada initiative.
Comments