Aging Infrastructure and a Changing Climate

Much of Nanaimo's stormwater system was built decades ago, during a time when rainfall patterns were less intense and less frequent. As this infrastructure ages, it is also facing heavier rainfall and rising seas, driving the need for change.

Why Aging Infrastructure Matters

Older pipes, culverts, and catch basins were designed for "normal" storms, not the extremes we see now. That means older infrastructure:

• Has limited capacity to handle high volumes of water
• Is more prone to blockages, overflows, and failures
• Requires more frequent maintenance and upgrades to remain effective
• May be deteriorating and require replacement
• May not address more recent objectives for protecting waterways

Storm Events That Overwhelmed the System

Recent storms have highlighted the limitations of our aging infrastructure:

• May 26, 2016:  An intense storm hit the North Nanaimo area, flooding and damaging some private properties, including the intersection of Ptarmigan Way and Seabold Road, the Woodgrove Mall parking lot and the Bay Department Store. Other stormwater sewer outfalls were also affected, particularly those located off Icarus Drive. The May 2016 storm was a 100-year storm event - having only a 1% chance of occurring in any given year.
• September 16, 2018:  A rare and severe storm dropped 39.8 mm of rain in one hour in North Nanaimo, causing localized flooding around Woodgrove Mall, Costco and Home Depot. This damage was more extensive than the damage that occurred in 2016.
• November 2021:  An atmospheric river affected a broader area of Nanaimo, pushing creeks and marshes to unusually high levels and causing infrastructure stress.

Following the 2016 and 2018 flooding events, projects related to mitigating such flooding and flood damage were incorporated into the capital plan and built and additional projects are scheduled to begin. 

Acting on Climate Change

Our coastal location makes us especially vulnerable to a changing climate. Flooding and sea level risk threaten areas like downtown Nanaimo, Departure Bay, Duke Point and Protection Island.

That's why protecting the natural environment, meeting our climate emission targets and preparing for the impacts of climate change is an important priority for the City of Nanaimo and the community that lives here.

Learn about how we're protecting the environment and responding to climate change and sea level rise in the City Plan, on our Green Initiatives page and through the Sea Level Rise Management Plan.