by Anne Naumann
Calgary River Valleys (CRV) is a non-profit organization dedicated to building a strong and effective voice for river valley protection and water quality in Calgary. We consider ourselves to be “the voice of our rivers”.
In addition to our annual projects, planting native vegetation along riverbanks and counting Brown Trout spawning nests in the Elbow River as an indicator of river health, CRV also provides educational input to Calgary’s urban planning process, focusing on the impacts to Calgary’s rivers, creeks, streams, and wetlands.
Recently, CRV has been reviewing the City of Calgary’s project to build an eight-lane major bridge across the West Nose Creek valley (six lanes plus two bike lanes), which involves a plan to artificially straighten the creek. The City considered three options for this bridge design and managing West Nose Creek at 144 Ave NW (see picture): Option 1 was to straighten the creek and put it into a large culvert under the roadbed. Option 3 was to leave the creek alone and build a non-symmetrical (or skewed) bridge with retaining walls along the creek valley to prevent bridge support erosion. Option 2, which was selected, proposes to straighten the creek, and build a symmetrical bridge with sloped concrete sides underneath it.
We have provided some input to the City about this project. First, the creek valley is a wildlife corridor, in which deer, moose, coyotes, skunks, and smaller creatures live and travel. The proposed bridge design effectively removes the wildlife corridor there and replaces it with steep concrete slopes under the bridge, which will be lighted at night, a common deterrent to wild creatures. Will wildlife be forced up onto the roadway to move through the creek valley, leading to more vehicle-wildlife collisions? The addition of sound barriers on either side of the proposed leaves wildlife very little choice of how to cross.
Second, natural bends or meanders in a river or creek allow its water to slow down during high flow events or flooding. The slower moving water at the inside bends of a meander provide resting spots for fish. Removing the meander at 144 Ave NW so West Nose Creek runs at 90 degrees to the roadway will result in the loss of fish habitat and the loss of the creek’s natural ability to slow down and absorb high water flows.
Calgarians are proud of our river and creek valleys, and our city policies state that we strive to protect the wildlife that lives in these areas. However, it seems there may be a disconnect between policies and practice in how some urban planning decisions are made, such that individual projects are not considered wholistically for their cumulative impact. We believe Calgarians care about these kinds of issues. CRV will continue to liaise with the City of Calgary and other organizations to see if a better balance can be made between the environmental costs and the economic costs for projects like this new bridge. If you want more information, visit our website at www.CalgaryRiverValleys.org.