Improving flood protection and fish habitat in Deep Cove

Deep Cove residents and businesses are now better prepared to weather future storms – and ready to welcome fish back to lower Gallant Creek.

The recently completed Gallant Avenue storm culvert project increased the size of the existing pipe from 1.2 metres to approximately 2.1 metres in diameter – big enough to stand a king-sized bed on end inside it – to handle anticipated increases in stormwater flowing into Deep Cove as a result of our changing climate. 

“In 2014 and 2018, flooding along Gallant Creek caused significant damage to local homes and businesses when heavy rains overwhelmed the existing culvert,” says Wendelin Jordan, project manager. “We needed to replace this critical infrastructure to ensure the community is protected from the impact of extreme rainfall in the future.” 

Along with being able to handle a 1-in-200-year flood, the expanded 150-metre-long storm sewer is designed to be more resilient to prevent flooding caused by fast-moving masses of water, branches, mud and rocks that can block culverts.

Planning the project  

Installing these large infrastructure sections in a busy residential and commercial area required months of planning and close collaboration across several DNV departments.

A temporary detour on Naughton Avenue was created to ensure safe and efficient traffic flow for everyone in and out of Deep Cove during construction work.

“We made every effort to minimize the impact on the community and local businesses,” says Jordan.

The sheer size of the new Gallant infrastructure required equipment rarely seen on District projects.

The excavator needed to lift heavy culvert sections was so massive it had to be transported on four separate trucks and assembled by crane on site, and a 160-tonne crane was required to move the larger pieces of the new culvert into place.

Before pieces of the culvert could be assembled, the project team first needed to untangle the patchwork of underground utilities beneath Gallant Avenue.

“Deep Cove was initially a cottage community, so there was a jumble of old and new utilities that crossed under the street,” says Jordan.

As a result, many utilities needed to be relocated to make space for the new culvert, which added to the logistical challenge of minimizing traffic disruption and maintaining access to the village centre and nearby homes.

Connecting with nature and restoring fish habitat

Solving the flooding issue in the Gallant area was the project’s top priority. Still, the overall plan had other objectives, including restoring fish habitat and improving this section of Gallant Creek so locals and visitors can have better access to nature.

One way to restore fish habitat was to make parts of the once-hidden creek visible. Instead of being hidden in a pipe underground in Panorama Park, the creek now runs freely through a channel, and there is a viewing platform behind the cultural centre where visitors can get a closer look.

“I take my children here on the weekends,” says Jordan. “We enjoy watching the native plants grow along the channel.”

Cedar logs have been anchored to the bottom of the channel to provide shade, shelter and resting spots for fish and other aquatic species. Staff also designed step-pools for fish passage, they embedded boulders, and have planted native plants and vegetation. These features dramatically improve the creek habitat.

“Gallant Creek is now providing aquatic species with additional space to thrive,” says Erika Nassichuk, environmental protection officer. “This project shows what can be accomplished when both engineering and riparian habitat requirements are considered and incorporated into the design from day one.”

Improving tree health, water quality

The project also provided an opportunity to use Silva Cells to encourage the growth and health of the newly planted trees along Gallant.

The modular units are placed around tree pits to allow large amounts of soil to remain uncompacted while also supporting the sidewalks above. The open design of the cells enables roots to grow well and water to flow underground through them. This helps improve local water quality as it retains and filters stormwater ­­­before it enters nearby Gallant Creek.

“With a project like this, we hope to leave a legacy of livability, and we feel we’ve accomplished this. Along with protecting homes and businesses from flooding and restoring aquatic habitat, we have also upgraded the village plaza, created new sidewalks, planted new vegetation, and improved utilities. These things will benefit the community now and into the future,” says Jordan.

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