WC141 MarApr 2025 - Magazine - Page 22
STORMWATER
PERMEABLE
POTENTIAL
Unlocking stormwater solutions
for Canadian municipalities with
innovative permeable technologies.
BY CORINNE LYNDS
S
TORMWATER MANAGEMENT remains a critical issue for Canadian municipalities, engineers,
and environmental consultants. With increasing
urbanization and climate change impacts, traditional
stormwater infrastructure faces growing strain. Permeable surfaces offer a sustainable, climate-resilient solution
to mitigate urban flooding, reduce runoff, and improve water
quality. This article explores key permeable technologies,
their applications, and considerations for implementation in
Canada’s diverse climates.
POROUS ASPHALT is a sustainable paving solution designed with a
reduced fine aggregate content, creating void spaces that allow water to
infiltrate through the surface. Beneath the asphalt lies an open-graded
stone bed that acts as a reservoir, temporarily storing stormwater. This
system effectively manages runoff by capturing, filtering, and gradually
releasing stormwater into the soil or a drainage system, reducing the
risk of flooding and erosion. Additionally, porous asphalt helps recharge
groundwater, improves water quality by trapping pollutants, and
minimizes the urban heat island effect due to its open structure.
Applications:
Primarily used in parking lots, pathways, and low-traffic areas, porous
asphalt is a cost-effective solution for municipalities seeking to reduce
stormwater volumes and enhance local flood mitigation strategies.
Fairford’s fresh look
Toronto’s Green Streets Program integrates permeable pavements,
including porous asphalt, to address urban runoff at the source. By
facilitating direct infiltration through the pavement surface, porous
asphalt reduces the amount of runoff entering storm sewer systems,
alleviating pressure on municipal infrastructure. Notably, Raindrop
Plaza transformed a former traffic island and right-turn lane into a
vibrant parkette featuring porous asphalt that supports groundwater
retention and tree growth. The site also includes the “Where the Water
Flows” thermoplastic mural, illustrating the relationship between
stormwater management and urban greenery.
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WATER C AN ADA • M ARCH/APRIL 2025
Why it’s a good option for Canadian climates:
Porous asphalt is designed to withstand freeze-thaw cycles, provided
there is regular maintenance such as vacuum cleaning to prevent
clogging. This ensures long-term performance in regions subject to
harsh winters and fluctuating temperatures.
WAT E R C A N A D A . N E T
Toronto.ca
Raindrop Plaza, a green infrastructure project in Toronto, showcases the
successful use of porous asphalt to enhance stormwater management.
