WC128 JanFeb2023 - Magazine - Page 8
STORMWATER
Flow No!
York Region’s Inflow and Infiltration Reduction Standard
BY RANIN NSEIR, M.ENG., P.ENG, AND MELINDA SZARICS
I
York Region in action
In 2011, The Regional Municipality of York developed its first
I&I Reduction Strategy, in collaboration with its nine local cities
and towns, which set a target to reduce 40 million litres per day
(MLD) of I&I in the York Durham Sewer System by 2031.
The Region uses flow monitoring data to identify areas of
the system highly susceptible to I&I by analyzing peak wet and
average dry weather flows. Its long-term flow monitoring program
provides accurate, continuous, near real-time and reliable flow and
rainfall monitoring data sourced from more than 70 rain gauges
and 290 flow monitors in regional and local municipal wastewater
Ranin Nseir
Melinda Szarics
Ranin Nseir, M.Eng., P.Eng., is
a project manager with System
Sustainability Management leading
York Region’s long-term Inflow
and Infiltration (I&I) Reduction
Strategy and Analysis.
Melinda Szarics is a
chemical engineering
student at the University
of Toronto.
The Inflow and Infiltration Strategy and Analysis team at
York Region consists of a group of infrastructure engineers,
coordinators and engineering students, reducing I&I with a
data-driven and strategic approach.
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WATER C AN ADA • JANUARY/ FEBRUARY 2023
systems. They also proactively manage I&I in new community developments through standardized region-wide requirements which
enhance system resilience to climate change, free up capacity taken
up by excess water and reduce the risk of overflows.
In 2021, halfway through the I&I Reduction Strategy, York
Region, local cities and towns, and development industry
partners have reduced I&I by more than 22 MLD, equivalent
to wastewater flow from almost 24,000 homes. The Region will
continue to track I&I reductions and drive investigative and rehabilitative work in high-priority areas in the existing wastewater
system and implement watertight requirements through new I&I
standards in new systems.
York Region’s I&I Reduction Standard
I&I must be both reduced within the system and prevented in
newly constructed sewers. Data from the Region’s flow monitoring program and lessons learned from existing practices has
determined updates and more detailed requirements were needed
to design, construct, inspect and test mainline sewers, maintenance holes and lateral pipes to supplement existing municipal
and Provincial standards.
In 2011, York Region published a Sanitary Sewer System
Inspection, Testing and Acceptance Guideline which several local
cities and towns adopted. Newly developed public and private
partnership programs further encouraged implementation,
providing capacity incentives. However, there was still a need for
consistent I&I reduction requirements in both the public and
private right of way. To fill this gap, York Region developed the
Inflow and Infiltration Reduction Standard for Sewers Servicing
New Development, which was endorsed by York Regional Council in February 2022.
To ensure the Standard is practical, implementable, cost-effective, and easily adoptable by designers, inspectors, contractors, and
other industry stakeholders, the Region engaged with all stakeholders and committees at various stages and on a variety of topics.
The Standard introduced new design, construction, and inspection requirements on both public and private sanitary infrastructure to ensure watertightness and enhance public environmental health and safety by reducing the probability of basement
flooding and raw sewage spills into the environment.
As one of only a few regional municipalities developing
standards specifically targeting I&I, York Region’s new Standard
adopts best management practices and drives consistent I&I
reduction requirements across all nine local cities and towns.
York Region
NFLOW AND INFILTRATION (I&I) happens when
groundwater, stormwater or snowmelt enter the sanitary sewage system through sump pumps, downspouts, foundation
drains and/or holes and cracks in pipes, which can lead to
basement flooding, less efficient sewage treatment, overflows
into the environment and reduced life expectancy of infrastructure. With increasing severity and frequency of rainfall events
due to climate change, the negative impacts of I&I are more
keenly felt by municipalities, pushing them to develop strategies
to meet the increasing risks.
