Reducing erosion, flooding, and pollution while improving fish and wildlife habitat

By District Staff on Wednesday, Mar 6, 2019

We’re working to reduce the pollution in our rivers, creeks, and streams that comes from stormwater runoff, while at the same time improving wildlife habitat and protecting stream banks from erosion. 

We’ve got a big plan that is nearing completion called the Integrated Stormwater Management Plan (ISMP), however many of the best practices for stormwater management are already being incorporated into our capital works and operational programs.

The Keith Road bridge replacement project is a great example of the improvements we’ve made.

Stormwater management at the new Keith Road Bridge

The old fashioned approach to stormwater management was to direct rainwater runoff from paved surfaces like roads and sidewalks through a network of curbs, gutters, and pipes, into nearby creeks and streams.

This approach results in significant impacts to watershed health, including degradation of habitat, streambank erosion and deterioration of water quality.

So, when designing the new Keith Road Bridge, we jumped on the opportunity to include innovative green infrastructure that captures, slows down, filters, and re-directs the runoff, simulating natural conditions and reducing impacts to nearby waterways.

Additionally, we enhanced the riparian area along Lynn Creek in the vicinity of the bridge.

Here are examples of the green infrastructure techniques we used:

Bioswale 

A bioswale is a landscaped area that collects, slows down, and filters stormwater runoff. At Keith Road bridge, the bioswale removes roadway pollutants, such as gasoline, motor oil and rubber, which improves the water quality in Lynn Creek and allows more of the stormwater to soak into the ground.

Image of a bioswale along Keith Road bridge
A bioswale alongside Keith Road bridge helps improve water quality in Lynn Creek

Flat curbs

A flat curb allows water to run off paved surfaces and onto natural surfaces, such as stones and grass. This slows down the water and allows it to soak into the soil at a more natural rate, while filtering out some pollutants. Flat curbs were used in the new parking lot at Bridgman Park. 

Image of a flat curb in a park, used to manage stormwater flow
A flat curb used in the parking lot at Bridgman Park helps water soak into the soil, filtering out pollutants

Catch basin dispersion drains

The catch basins by the bridge collect runoff from paved surfaces that have curbs and gutters, and includes a dispersion drain that allows water to soak into the ground below the catch basin. Once the ground is saturated, stormwater  flows into the piped system and is carried away. This helps avoid flooding.

Riparian zone protection

A riparian zone is the interface between the land and a river, creek, or stream. At Bridgman and Seylynn Parks, we protected this valuable wildlife habitat by relocating creek side walking trails 15m from the edge of the creek, restoring creek banks along the decommissioned trails, installing 950m of new cedar fencing to reduce erosion on streambanks, and replacing invasive plant species with native plants.

A photo of riparian zone protective fencing in Bridgman Park
Cedar fencing protecting the sensitive riparian areas in Bridgman Park along Keith Road bridge

Replanting

The vegetation in riparian zones helps fish and the aquatic ecosystems by providing shade to keep water cooler, creating habitat for fish to hide in, promoting vegetation growth to provide nutrients, and providing erosion protection with root structures. As part of the Keith Road Bridge project, we planted more than 465 trees and 19,000 shrubs to restore the forest understory and riparian habitat.

Native plants along the riparian area adjacent to Keith Road bridge
More than 465 native trees and 19,000 native shrubs were planted to restore the understory and riparian habitat

Next steps for the Integrated Stormwater Management Plan

Staff are currently finalizing the new ISMP. Once completed, the next step will be to start implementing the recommendations it contains, in order to meet nine key stormwater management objectives.

They are:

  1. Maximize base flows
  2. Maximize fish populations
  3. Maximize riparian ecosystems
  4. Maximize social-ecological connection
  5. Maximize sense of safety and security
  6. Minimize impacts on First Nation traditional use activities
  7. Maximize natural assets
  8. Minimize damage to infrastructure
  9. Minimize institutional costs and conflict 

You can learn about all nine objectives, plus get additional plan details, on our website.

Learn more about the ISMP

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