The Black Creek Sanitary Drainage Area Servicing Improvements Environmental Assessment Study aims to address capacity issues in the Black Creek Sanitary Trunk Sewer system to service projected population growth, reduce surcharging during wet weather, reduce inflow/infiltration, and reduce combined sewer overflows. Potential solutions being considered include new relief trunk sewers, combined sewer overflow storage tanks, flow diversion, and maintenance hole adjustments. The study will evaluate alternatives and select a preferred solution to address the identified problems while minimizing impacts on the natural, social, and technical criteria.

1. Black Creek Sanitary Drainage Area Servicing Improvements
Class Environmental Assessment Study
The purpose of this Environmental Assessment Study is to
recommend improvements for the Black Creek Sanitary Trunk Sewer
(STS) system
This Environmental Assessment Study is not focused on basement
flooding
• The Basement Flooding Protection Program is separately addressing basement
flooding issues at the local sewer level
• Information from the Basement Flooding Protection Program studies will
inform the analysis and recommendations made for the Black Creek STS
Environmental Assessment

2. Welcome
Black Creek Sanitary Drainage Area
Servicing Improvements
Municipal Class Environmental Assessment Study
Public Information Centre
Date: April 26 and April 28, 2016
Time: 6:00 pm to 8:00 pm
Please sign in to receive project updates on the study.
Please provide your comments by completing a
comment sheet and placing it in the box or
forwarding it to the Project Team by May 20, 2016.

3. Purpose of Today’s Information Session
• Present the purpose and objectives of the study
• Provide background on the Black Creek Sanitary Trunk Sewer System
• Present the problems and opportunities for the study
• Present potential solutions to be considered
• Present draft criteria for evaluating alternatives
• Receive your comments
We Want to Hear From You
You can participate by:
• Signing in at the attendance register
• Reviewing the display panels
• Asking questions from City Staff and Consultants
• Completing a comment form
• Participating in future Public Information Centres
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4. Study Purpose and Objectives
The purpose of this study is to assess capacity issues with the Black
Creek Sanitary Trunk Sewer (STS) system, identify solutions and
develop a plan to achieve the following objectives:
• Service projected population growth in the sanitary drainage area to 2041
• Reduce surcharge levels in the Black Creek STS during wet weather events
• Reduce combined sewer overflow discharges to Black Creek
• Reduce Inflow and Infiltration into the Black Creek STS
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5. Municipal Class Environmental Assessment Process –
Schedule C
• Identify the
Problem/
Opportunity
• Consult with
Public, Agencies,
Stakeholders
• PIC #1 April 2016
Phase 1
• Review of
background
studies, relevant
EAs and existing
conditions
• Develop and
Evaluate
Alternative
Solutions
• Consult with
Public, Agencies,
Stakeholders
• PIC #2
• Select a Preferred
Solution
Phase 2
• Identify Design
Concepts
• Consult with
Public, Agencies,
Stakeholders
• PIC #3
• Select the
Preferred Design
Concept
Phase 3
• Complete
Environmental
Study Report
• File
Environmental
Study Report for
Review by Public,
Agencies,
Stakeholders
Phase 4
We
are
here
30 Day
Review Phase 5
• Design,
Construct and
Monitor
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6. Black Creek Sanitary Trunk Sewer System and Drainage
Area
• The Black Creek STS was built in the 1960’s
• It is a tributary to the Humber Sanitary Trunk Sewer and discharges into the Humber
Wastewater Treatment Plant
• The Black Creek STS is 15 km long, from Finch Avenue West to Scarlett Road
• The Black Creek STS services a sanitary drainage area of 5,700 ha
• It services a population of 386,100 in 2011 (70% residential, 30% employment)
• 80% of the sanitary drainage area has separated local sanitary and storm sewers; 20% has
local combined sewers
• There are 3 combined trunk sewers that connect to the Black Creek STS:
• Hillary Combined Trunk Sewer
• Mt. Dennis Combined Trunk Sewer
• St. Clair Combined Trunk Sewer
• There are 8 combined sewer overflow structures
that control flows to 7 combined sewer outfalls
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Overflow structures divert,
or bypass flows to relieve
an overloaded sewer
Outfalls from the combined
trunk sewers to Black Creek

7. Study Area (portrait orientation)

8. Study Area (portrait orientation)

9. Separated Sanitary Sewer System
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10. Combined Sanitary Sewer System
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11. Servicing Population Growth
Problem:
• Residential and Industrial/Commercial/Institutional
populations are expected to grow within the study
area
• Population growth may increase capacity constraints
on the Black Creek STS
Objective:
• Ensure capacity in the Black Creek STS to service
population growth to 2041 and beyond
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12. Sanitary Trunk Sewer Surcharge Levels During Wet
Weather Events
Problem:
• Surcharge of the Black Creek STS happens when the flows through the trunk
sewer exceed its design capacity
• This may occur due to inflow during large storm events when large amounts of
stormwater enter the Black Creek STS.
• Excessive flows in the Black Creek STS may backup into local sewer systems, valleys and
ground surface.
Objective:
• Reduce Black Creek STS surcharge levels to the ground surface and valleys and
potential impacts on the local sewer systems
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13. Water Inflow/Infiltration to the Black Creek STS
Problem:
• Significant amounts of wet weather flows enter the Black Creek STS during
rain events. The sources of the inflow/infiltration may be:
• Connections in the local sanitary and combined sewers
• Leakages in the trunk sewers, for example, openings in the maintenance hole covers
which allow water into the sewer
• Water level increases in the creek/rivers, water gets inside the trunk sewer via
combined sewer outfalls and manholes that are located in the floodplains
Objective:
• Reduce Inflow/Infiltration water entering the Black Creek STS to reduce
capacity constraints.
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14. Sanitary Trunk Sewer Surcharge Levels and
Inflow/Infiltration (I&I) During Wet Weather Events
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15. Combined Sewer Overflows
Problem:
• Combined trunk sewers carry a mixture of stormwater and domestic
sewage. During rainstorms, or high levels of snowmelt, excess flow can
result in discharge of combined sewer overflow from outfalls to Black Creek
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Objectives:
• Reduce discharges of combined sewer overflows to
meet the Ministry of Environment and Climate
Change Procedure F-5-5
• Procedure F-5-5 requires efforts be made to eliminate
combined sewer overflows
• Improve water quality in Black Creek and
downstream watercourses

16. Potential Solutions Being Considered for the
Development of Alternatives
• New relief trunk sewer: Construction of new trunk sewers to accommodate future growth
and provide a relief to Black Creek Trunk Sewer
• Combined sewer overflow storage tank: Temporary storage tanks allow storage of
additional flow during storm events until there is capacity in the downstream infrastructure
• Flow diversion: Diverting flow to other sewers in specific locations to address capacity
constraints in those locations.
• Flow control structures: Making adjustments to existing flow control and combined sewer
overflow control structures
• Maintenance hole adjustments: Raise maintenance holes and
reduce number of openings in maintenance hole cover
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Storage tanks are underground and
surface areas are landscaped to
pre-construction conditions

17. How We Are Developing Alternative Solutions
Technical, environmental and cultural studies are
being completed. The work to develop alternative
solutions involve:
• Review of background information and previous studies
• Data collection
• Rainfall and flow monitoring
• Water quality sampling
• Modelling trunk sewer capacity and combined sewer
overflows under current and future conditions
• Geotechnical and other field investigations
• Environmental impact assessments
• Stage 1 Archaeological and Cultural Heritage
Assessments
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18. Draft Evaluation Criteria for Alternative Solutions
Alternative solutions and selection of a preferred alternative will be evaluated
based on their ability to address the Study’s Problem and Opportunities,
stakeholder input, and potential impacts based on the criteria below
Natural
Environment
• Terrestrial impacts (e.g. trees,
vegetation, wildlife)
• Aquatic habitat impacts (e.g.
water quality, erosion and
sedimentation impacts)
• Soil
• Geology
Social • Public Health and Safety
• Disruption to the community
(e.g. noise, dust, traffic)
• Impact to public property and
recreational use
• Cultural heritage and
archaeological impacts
• Odour issues
Technical • Constructability
• Regulatory approvals
• Capacity for future growth
• Reduce combined sewer overflows
• Reduce surcharging
• Impacts to local infrastructure and the
Humber Wastewater Treatment Plant
Cost • Capital cost
• Risk/benefit analysis
• Operations and maintenance costs
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19. Next Steps for the Black Creek Sanitary Drainage Area
Servicing Improvements Environmental Assessment
Phase Phase 1 Phase 2 Phase 3 Phase 4
Task
Identification of Problem and
Opportunity
Identification of Alternative
Solutions
Identification
of Alternative
Design
Concept
Environmental Study
ReportIdentify
Alternatives
Assess and
Recommend
Preferred
Alternative
Month N D J F M A M J J A S O N D J F M A M J J
Year 2015 2016 2017
PIC#1 PIC#2 PIC#3
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After today’s meeting:
• Finalize hydraulic model
• Develop alternative solutions
• Evaluate alternative solutions and recommend a preferred solution
• Present alternatives evaluation and preferred solution at Public Information Centre #2 in late 2016 for
feedback
30 Day
Review

20. Thank You for Attending
We welcome your feedback. Please fill out the comment sheet provided.
Following this PIC, the project team will review and consider your
comments in the evaluation of alternative solutions.
Mae Lee
Public Consultation Unit
City of Toronto
55 John Street, Metro Hall 19th Floor, Toronto, ON M5V 3C6
Phone: 416-392-8210 Fax: 416-392-2974 TTY: 416-338-0889
Email: rmlee@toronto.ca
Visit: toronto.ca/blackcreekstudy
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