Urban Creek Management

In urban areas, healthy aquatic and riparian ecosystems provide us with a multitude of benefits.  They can provide habitat and wildlife corridors for terrestrial and aquatic species and are often home to species at risk.  They can also increase property value and provide green space for community members to enjoy.  Furthermore, a diversity of native species in the riparian zone can help with flood and erosion control, stormwater management and filtering pollution before it enters our waterway.

Because of all of these ecological and cultural values, managing and restoring a creek has many opportunities and challenges. Unfortunately, the health of Joseph Creek as a functioning aquatic ecosystem has been shaped by decades of disruptive anthropogenic activities. Many sections of the creek are in fact man made channels with 90-degree corners and little to no fish habitat, native species, or natural water flow.  As a result of this, flooding, erosion, and monoculture have become common concerns along the creek. 

Golden Willow

Non-native invasive plants are a widely acknowledged threat to global biodiversity. “Species invasion is probably the second most important cause, behind habitat loss, of the overall decline in biodiversity and the changing composition of riparian communities.” (Naiman, Decamps, McClain, Riparia, p230).

Golden Willow, an opportunistic non-native species that thrives in disturbed riparian areas, has become the dominant plant surrounding Joseph Creek.  It is originally from Europe but has adapted well to BC climates and has established itself primarily along stream sides and wetland areas in the province. It has limited natural competitors in BC and is much more aggressive than native stream side plants (City of Cranbrook, 2015). This species of willow was introduced to Joseph creek many decades ago and has since spread from Idlewild lake to a vast majority of the creek. 

No one can deny how beautiful this tree is, however, it is the cause of many issues along the creek. Although it’s not listed as an invasive species, it displays many invasive characteristics. It has a very aggressive root system that encroaches and raises the streambed, thereby decreasing its capacity for holding water.  Golden Willows “have been choking out the [Joseph Creek] stream channel, exacerbating flooding and further habitat degradations” (Lotic Environmental, 2020).  The roots of Golden Willows produce thick mats that can grow completely submerged and physically alter the natural bank of the creek.

Willows spread through seed and vegetative methods.  Their vegetative spread, which happens through the rooting of shedding branches and the toppling of mature stems, is most concerning. Golden willows have brittle branches that easily break off.  These are then carried downstream and root themselves along the bank. These branches also tend to get tangled up and create micro dams downstream. Normally, when trees over mature they die but willows tend to topple under their own weight, take root and begin their vertical growth over again. This tendency, coupled with the layering and damming of branches downstream, significantly contribute to the flood potential and bank erosion issues found within Joseph Creek (The City of Cranbrook, 2015).

Because Golden Willow outgrows, outspreads, and outcompetes most plants, there are very few native species present along Joseph Creek. However, a diversity of streamside plants is essential to the health of a riparian ecosystem.  It stabilizes the banks, prevents erosion, acts as a buffer and filtration system, and creates shelter and habitat for wildlife.  Also, an established canopy provides shade which helps to regulate water temperatures and dissolved oxygen levels.

Although golden willows provide some of these benefits, Joseph Creek is desperately needing a multi-layered and biodiverse riparian zone. Many areas of the creek are adjacent to roads and paved recreational trails and without a naturally diverse riparian area, much of the runoff flows directly into the creek. Such is the case at 15th Avenue South and 1st Street South in downtown Cranbrook where Golden Willow were selectively targeted for removal.

Follow this link to learn more about how willow can become an invasive pest: 4(4) (hoadley.net)

15th Avenue South and 1st Street South Project

The City of Cranbrook, in collaboration with Columbia Outdoor School, has completed a channel reconstruction and rehabilitation project at 15th Avenue South and 1st Street South (click here to see a map of the project site). This project was on a 350m section of Joseph Creek that has been subject to recurring flooding and severe encroachment by Golden Willow. The goal of the project was to reduce flooding to the residences, business, and roads in the vicinity of the project area. By expanding the floodplain and replacing invasive tree species with native trees and shrubs, we have increased the capacity of the existing floodplain to better handle future flooding events. Through this work we have also created better-quality fish habitat in the channel reach.

After many years of consultation with the provincial Ministry of the Environment, Ktunaxa and ʔAq'am local governments and the Federal Government, this project received approval from the Department of Fisheries and Oceans Canada and was accepted as the best solution by all parties.

This project will immediately help protect the city’s infrastructure with flood and erosion control; in the long term, the aquatic ecosystem will also be significantly improved. The city worked closely with fisheries biologist and engineers to ensure all due diligence measures were in place to mitigate environmental impacts. A monitoring protocol was followed throughout the duration of the work, as well as afterwards, to ensure these measures were effective in protecting the natural ecosystem. The work commenced in the spring 2022 prior to the prescribed migratory bird nesting season and carried on later in the summer during the instream fisheries windows to minimize harm and disruption to wildlife. The final stage (staking and planting) was completed in late fall.

The role of Columbia Outdoor School in this project was to coordinate and manage the planting of the site. We were committed to creating a healthy biodiverse riparian area. Biodiversity is the variety of life (plants, animals, etc.) found in an ecosystem. This abundance is an indication of the health and resiliency of a system. By removing the Golden Willow that had become the dominant species along the creek and replanting with a variety of native plants, we have significantly improved the condition of Joseph Creek in this area.

Planting followed a plan prepared by a local environmental consulting company specializing in freshwater ecosystems. By identifying the riparian zones and planting appropriate species in each zone, we have maximized survival rate and ensured restoration success. Most species found within riparian ecosystems establish along a moisture gradient, with the most water tolerant species found at the lowest elevation and most drought tolerant found at the highest. In planting the native species found in the Cranbrook Ponderosa Pine zone, that are also appropriate for the moisture regime found along a stream, restoration efforts will be more efficient and effective.

This project will not only improve the functionality of the creek, it will also create a beautiful green space for citizens to come and enjoy the creek and reconnect with the natural environment, right in the center of the city.

Check out the pictures below of the project site in the 1970s.

Here is a photo of the newly constructed floodplain and live staking.

Stay tuned for pictures of the site in the spring once all the native shrubs and trees have sprouted.

To read about a similar project, follow this link: Whitehead Park | Friends of Tod Creek Watershed

Habitat Banking and the Diversion Project

When it comes to doing any type of work on a creek, there are many things to consider and several regulations to follow. All work that takes place in a creek must first be approved by the Department of Fisheries and Oceans Canada (DFO). This is because the Fisheries Act prohibits any activity that could result in the death of fish or the destruction of fish habitat. To get this approval from DFO, you must outline in detail the work you will be doing and why this work is necessary. The application must also include a plan that describes how you will first avoid, then mitigate and finally offset any fish or fish habitat concerns. If your project could result in harm to fish or fish habitat, an exception from DFO is required. As part of this exception, your project must include an offsetting enhancement project. This means that to counteract the possible harm, you must make an improvement to the aquatic ecosystem where the impacts will occur or elsewhere along the same creek. This offsetting condition is part of a system called habitat banking where you “bank habitat” by enhancing or restoring the watershed with measurable benefits for fish and fish habitat. You can then use this against work that needs to be done in or around water.

Click here to learn more about habitat banking.

The collaboration project between the city of Cranbrook and Columbia Outdoor School at 1st Ave South and 15th Ave South required this type of offsetting restoration work. While the project itself had the goal of decreasing flooding and long term, improving the quality of the riparian ecosystem, the authorization from DFO required that twice as much area as what is being worked on at 1st and 15th be enhanced somewhere along the creek.

Columbia Outdoor School, in a partnership with ʔAq'am Guardian in Training Program, has met this offsetting requirement by planting a section of the creek near Phillips Reservoir. The planting area is along a fish bypass channel which allows fish to go around the reservoir. This bypass was constructed in the 1970’s and has been left barren since. Due to the lack of riparian vegetation, this man-made stretch of the creek has the largest temperature uptake along the creek. See the graph below showing the temperature on August 11th, 2022 taken at 10 sites along Joseph Creek. The most upstream site (T8b) is above the proposed planting site and site T8a is just below. Between those 2 sites, we see a 7.9°C jump in temperature, by far the largest change in temperature along the creek.

The shade created by replanting native trees and shrubs will help reduce this uptake and maintain the water at a more suitable temperature for native fish species such as Westslope Cutthroat Trout. Approximately twenty years ago, temperature increases were identified by the local government and said to be negatively affecting native fish species in the creek. Five years ago, Columbia Outdoor School installed temperature loggers throughout the length of the creek and our readings have confirmed that water temperatures continue to rise. This temperature increase is further exacerbated by climate change. Planting this section of the creek will help mitigate these impacts by not only improving the water quality for fish, but also by creating wildlife habitat for various other species.