WC128 JanFeb2023 - Magazine - Page 10
STORMWATER
”By 2031, an estimated 4.3 MLD of I&I, equivalent to the daily wastewater flow
from about 4,500 homes, can be eliminated by adopting the new Standard.“
Time
Sanitary sewer flow response to a major storm event (100-year storm event)
in a new development built to existing standards (green) versus one built to I&I
Standard requirements (red).
Furthermore, the Standard is applicable to both private and public property development. In Ontario, public infrastructure up
to the property line is regulated by municipal standards, whereas
private sewers from property line to building face are governed
by Ontario Building Code. York Region’s Standard aligns with
the Ontario government’s standards, bridging the gap between
public and private side requirements.
The Standard features a guide to design and construction,
including tables and decision charts for material selection, service
connections and additional maintenance hole waterproofing
requirements, specifically for areas of high groundwater table
conditions. It also includes testing and inspection requirements,
namely new air testing and closed-circuit television requirements
THE PRIMARY GOALS OF THE STANDARD ARE TO:
Adopt best management practices for design and construction,
testing and inspection to address gaps identified in existing
standards
Drive consistent I&I reduction requirements across all nine local
cities and towns, especially for watertightness
Avoid unnecessary maintenance in the long term and reduce risk
of basement flooding, while freeing up capacity to accommodate
growth
Increase system resiliency to extreme rainfall events occurring
more frequently due to climate change
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WATER C AN ADA • JANUARY/ FEBRUARY 2023
Meeting the challenges
Although the new Standard could increase costs by approximately 15 to 20 per cent, a cost-benefit analysis estimates that avoided
impacts can save up to $258,000 per kilometre of pipe. These
avoided costs include additional maintenance, pumping and
treatment costs, spills to surface waters, environmental fines, and
residential sewer backups.
To meet the new requirements, sufficient skilled tradespeople
may not be available at early phases of implementation. However,
availability will increase as demand increases. Implementation of
the Standard is predicted to create additional jobs for consultants
and inspectors in York Region who will ensure conformance with
testing and monitoring requirements.
On the horizon
York Region is implementing the Standard in collaboration with
its nine local cities and towns who will require development
applicants to meet the Standard as a condition of development
approval secured through subdivision and site plan agreements
and associated securities. By the end of the adoption period, all
local municipalities will also have integrated the Standard into
their local standards either by incorporating it into relevant sections or creating an amendment to existing design and construction standards.
Implementing the Standard will help York Region achieve its
overall reduction target of 40 MLD. By 2031, an estimated 4.3
MLD of I&I, equivalent to the daily wastewater flow from about
4,500 homes, can be eliminated by adopting the new Standard.
In selected areas, the Region will undertake pilot flow monitoring programs to demonstrate the effectiveness of the Standard
during the implementation phase.
This approach for proactively preventing I&I can be integrated
into any municipal standards, adding a higher level of stringency
beyond other codes and standards. With the impacts of climate
change increasing the intensity of storm events, preventing I&I
in new developments is a cost-effective way to improve resiliency
and free up capacity.
WAT E R C A N A D A . N E T
York Region
Sanitary Sewer Flow Rate (L/s)
with specifics on equipment, timing, frequency and procedures.
These tests supplement Ontario Building Code requirements for
service connections on the private right of way. Lastly, there are
flow monitoring technologies and analysis methods, with a focus
on new optional flow monitoring and thresholds for performance
evaluation.
