WC139 NovDec 2024 - Magazine - Page 13
As shared in a BBC story earlier this year, “there has been
increasing public anger at the levels of sewage being discharged
into England’s rivers and seas,” and the purpose of the South
Elmsall constructed wetlands will be to treat storm flows during
heavy and prolonged rainfall and in so doing, reduce those controversial overflow discharges.
Residual benefits of the site, which will be the size of five
football fields and home to an estimated 22,000 plants, includes
increased biodiversity and attracting wildlife such as bees, breeding birds, amphibians and reptiles and a 52 per cent reduction in
embodied carbon compared to traditional projects. Because the
constructed wetland uses a less energy intensive approach to treat
water, it’s expected to deliver a 53 per cent operational spend
(OPEX) savings annually.
The impact of local LIDS
Apart from dealing with such challenges as wastewater and the
threat of combined sewer overflow events the South Elmsall
project is designed to address, Ludlow says our new normal is
that “waste pollution comes from numerous sources. Not just
wastewater. Not just industrial discharges. It’s [coming from]
our urban spaces, our development, our agriculture. So when
you think about the variety of [pollution] sources, that’s where a
holistic solution is best.”
As such in an urban setting, she says there’s the need to
introduce more green infrastructure at the neighbourhood level
in support of existing grey infrastructure, such as bioswales, tree
trenches to prevent water from entering our sewers. And such
measures as creating riparian buffers to stabilize local river banks
and reduce the incidence of erosion.
Steven van Haren, Principal Engineer with WSP Canada says
“distributed LID-based stormwater controls have advantages
in terms of land savings and… often, bioswale-based systems
in parking lots have minimal maintenance costs that can be
bundled into facility maintenance budgets easily without added
complexity.” He adds that “all those variables reduce operating
costs, which can easily outweigh small capital cost increases.”
If designed properly, van Haren says LID (Low Impact Development) based systems, which combine natural and engineered
systems to reduce stormwater runoff “…can improve the aesthetics of traditional site plans [including] promoting biodiversity
particularly in urban areas where there is a lack of pollinators for
example.” He adds that “These systems reduce or mitigate the
urban heat island effect and provide preferred habitat for many
urban dwelling wildlife species.”
carbon and biodiversity credit goals. But no reality is more
pressing than the need to create more resilient cities in the face
of climate change.
“Hurricane Helene just showed us that nowhere is ‘safe’
from climate change-induced flooding,” observes van Haren.
“We need individual, property-based resilience assessments
and solutions to begin to address the flooding challenges our
municipal areas are already facing.”
It’s about breaking down barriers not only between municipalities and their respective suppliers, but also breaking down
interdepartmental silos that have sometimes existed in the past.
“It’s about everybody working together, from the planning
approvals… regulatory [services] and infrastructure, [including] community based housing and green spaces. All of that
comes into play,” says Ludlow. “Engaging everybody early
on in your solution development can really help further and
promote nature-based solutions.”
Solutions that ultimately help support existing grey infrastructure while creating greener, healthier and arguably most
importantly of all, more resilient communities.
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Greener Grey-Green Future
Any number of today’s realities could potentially catalyze the
update of grey-green and green-grey hybrid solutions; from
coping with aging infrastructure to recognizing the need to keep
a lid on major infrastructure costs to meeting newly established
WAT E R C A N A D A . N E T
WATER C AN ADA • NOV EMBER/ DECEMBER 2024
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