MMM Group Limited
Don River and Central
Waterfront Project
Municipal Class EA
Environmental Study Report
Prepared for: City of Toronto
COMMUNITIES
TRANSPORTATION
BUILDINGS
INFRASTRUCTURE
August 2012 | 10-08008-024-PM1
ES-1.0 EXECUTIVE SUMMARY
ES-1.1 Purpose of this Municipal Class EA
The Don River and Central Waterfront Municipal Class EA Project, (also known as the Don and Waterfront
Trunk Sewers and CSO Control Strategy), is a complex assignment with the goal of the eventual delisting
of the Don River and Inner Harbour as a polluted Great Lakes Area of Concern while sustaining the rapid
growth of Toronto efficiently and securely. Discharges from combined sewer overflows and storm sewers
were identified as principal sources of pollution in the City’s 2003 Wet Weather Flow Master Plan (WWF
MP) which must be controlled to reach this objective. In addition, the efficiency and security of the City’s
dry weather flow collection and treatment system is a key concern. Hence this project is intended to
provide a comprehensive systems integration approach which will incorporate the wet weather flow control
projects identified in Study Area 1 of the WWF MP with dry weather treatment and collection system
optimization. The intention is to build upon the results of the WWF MP to reach a cost-effective and
environmentally beneficial solution to these issues. The project was completed under the Municipal Class
Environmental Assessment process to ensure appropriate opportunities for public input and comment.
This Class Environmental Assessment was carried out as multiple undertakings relating to wet weather
flow control and dry weather collection and treatment system improvements. This Environmental Study
Report documents the findings and recommendations of the Class EA study concerning the improvements
to the portion of the wastewater collection and treatment system of the City of Toronto that drains to the
Ashbridges Bay Treatment Plant. The City of Toronto is the Proponent for this project. The anticipated
improvements include:
►
The provision of dry weather capacity for population growth up to the City’s current Official Plan of
2031.
►
The collection, storage and treatment of Wet Weather Flows (WWF) as identified through the City’s
2003 approved Wet Weather Flow Master Plan.
ES-1.2 Background
In 1987, the International Joint Commission (IJC) designated Toronto’s waterfront as one of 43 “Areas of
Concern” (AOC) in the Great Lakes Basin, largely because of impaired water quality conditions in the Don
River and the Inner Harbour. Toronto’s Inner Harbour represents one of the most degraded areas of water
quality due to both combined sewer overflows (CSOs) and storm sewer discharges. The Don and
Waterfront sanitary trunk sewer systems serve approximately 50% of Toronto’s population and carry
sewage from almost 270 square kilometers to the Ashbridges Bay Treatment Plant (ABTP). A significant
part of the area (i.e. the “old City of Toronto”) is served by combined sewers. These carry sanitary sewage
during dry periods and a mixture of storm runoff and sewage during wet weather periods. To avoid
overwhelming the ABTP during wet weather, there are a series of diversion structures within the system
which allow excess flows to overflow into the Inner Harbour and the Don River. There are about 50
overflow locations which have a CSO component to them and about a further 50 discharge points which
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are exclusively stormwater within the study area. There are many other stormwater discharge points
upstream of the study area in the former City of North York and in York Region north of the City boundary.
The City’s WWF MP outlines a hierarchy of measures to be implemented on a watershed-wide basis
designed to address the noted water quality impairment. This includes source controls (often referred to
as Low Impact Development – LID – techniques), conveyance controls and end-of-pipe controls.
Aggressive programs have been initiated by the City to implement source and conveyance controls which
the current study and resulting proposed projects have taken into account. The WWF aspect of this
project focuses on the end-of-pipe facilities recommended in the WWF MP for the study area. It will result
in a plan to build new infrastructure such as underground tunnels, tanks, and treatment facilities to
capture, store and treat combined sewer overflows before they flow into the Taylor/Massey Creek, Lower
Don River and Central Waterfront.
The Dry Weather Flow (DWF) component of this project focuses on changes and upgrades needed in the
sanitary trunk sewer system to make sure the system continues to function correctly and sufficiently as the
City grows. In addition, it strives to improve the level of security of operation of the system by including
redundancy in the system in case of failure of a critical link in the Coxwell Sanitary trunk sewer.
ES-1.3 Municipal Class Environmental Assessment
The Project is being conducted as a Municipal Class Environmental Assessment (EA), Schedule C and will
fulfill the requirements of the Ontario Environmental Assessment Act, as described in Section 1.3 of this
document.
ES-1.4 Canadian Environmental Assessment
The Canadian Environmental Assessment Act (CEAA) is “triggered” when a federal authority:
►
Is a proponent of the project;
►
Provides financial assistance to a proponent to enable a project to be carried out in whole or in part;
►
Sells, leases, or otherwise transfers control or administration of federal land to enable a project to be
carried out; or
►
Provides a licence, permit or an approval that is listed in the Law List Regulations that enables a
project to be carried out.
(Source: www.ceaa-acee.gc.ca)
For this Project, the two possible CEAA “triggers” that apply are:
►
federal approvals will be necessary; and/or
►
funding assistance may be provided.
The first CEAA related step will be to develop a project description and scope for this Project (the Don
River and Central Waterfront Project).
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Since this Project will require a federal multi-jurisdictional assessment, the Canadian Environmental
Assessment Agency (CEA Agency) will act as the Federal Environmental Assessment Co-ordinator
(FEAC). After review of the Project description by Federal Agencies, a determination will be made
concerning which agencies are the Responsible Authorities (RA), and the level of federal environmental
assessment needed. Based on preliminary feedback obtained during this study, it is anticipated that this
Project will not be identified in the Comprehensive Study List Regulations of the CEAA, and therefore, the
appropriate level of assessment will be a “Screening Report” for the Federal Environmental Assessment.
ES-2.0 PROBLEM/OPPORTUNITY STATEMENT
The Don River and Central Waterfront Class EA is a multi-objective project to address a number of
problems/opportunities in the ABTP drainage area.
a) Addressing wet weather flows in the study area
In 1987, the International Joint Commission identified the City of Toronto Waterfront as an Area of
Concern (AOC) in the Great Lakes Basin. This was largely due to poor water quality and sediment
conditions in the Inner Harbour, and loss of fish habitat and contaminant levels in fish. Flows from
both storm sewers and combined sewers – sewers that contain both sanitary sewage flows and
stormwater - were identified as the main sources of the problem, particularly in the Don River and
Central Waterfront.
Approximately 100 sewer outfalls discharge directly into the Don River and the Inner Habour during
heavy rainfall or snowmelt. Of these outfalls, 50 contain CSOs while the remainder comprise only
stormwater. The project builds on the outcomes of the approved Wet Weather Flow Master Plan
(2003) and provides an opportunity to develop a solution to the Wet Weather Flow problem by finding
the most preferred method of capturing and treating the combined sewer overflows. This will
contribute to eventual improvements in water quality and fish habitat.
The current study considers collection, storage and treatment of the CSOs from all 50 outfalls
containing CSOs, plus 4 large outfalls which contain only stormwater. These 54 outfalls are at a total
of 47 locations within the Study Area (i.e. some locations have more than one outfall). The remaining
outfalls, which will be addressed in future studies, comprise only stormwater.
b) Addressing dry weather flows in the study area
The other main component of the study relates to dry weather flow problems/opportunities, namely:
►
ensuring sufficient capacity in the dry weather flow collection system within the study area to
accommodate future growth.
►
having sufficient redundancy for the Coxwell STS to increase the security of the system and to
enable maintenance and repairs.
Through the current study, upgrades necessary to the sanitary trunk system to improve operations and
support future growth needs are identified.
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c) Additional considerations
Two subsidiary components of the dry weather flow component of the Class EA involve:
i)
An evaluation of co-location of the current sludge transfer forcemains with infrastructure from the
project and routing options to provide a more sustainable method of transferring the Humber
Treatment Plant sludge to the Ashbridges Bay Treatment Plant.
This area of study was designed to address the current disadvantages associated with the current
method of transferring sludge through twin forcemains which outlet to the Mid-Toronto Interceptor.
Options were evaluated in this study which might take advantage of opportunities for synergies
with the infrastructure proposed to convey the wet weather flows.
ii)
An evaluation of the future of the North Toronto Treatment Plant.
This evaluation was designed to consider possibilities for improving the NTTP effluent to reduce
impacts of ammonia and phosphorous on the Don River. The upgrade alternatives considered in
this study were reviewed in order to assist in determining whether or not to keep the NTTP in
service.
d)
Integration of Dry and Wet Weather Solutions
The potential opportunities to integrate the dry weather and wet weather solutions were considered to
be a key opportunity for the current study. Both dry and wet weather alternatives and solutions were
reviewed and evaluated with a view to identifying potential synergies between the two. For example,
potential environmental and cost benefits could be realized by identifying dual purpose infrastructure
that could both store and treat wet weather flows and provide additional security in the dry weather
flow collection system.
ES-3.0 STUDY AREA
The Study Area for the Don River and Central Waterfront Project includes the tributary areas from the
Lower West Don, Lower East Don, Lower Don River and Taylor/Massey Creek subwatersheds and the
City’s Waterfront Interceptor system for the downtown core. These areas total approximately 267 sq. km
and are tributary to the Ashbridges Bay Treatment Plant (Figure ES3-1). The ABTP sewershed is served
by the following tributary trunk sewer systems:
1. Don Sanitary Trunk Sewer System.
2. Waterfront Interceptor Sewer System.
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Figure ES3-1: Study Area
The Don and Waterfront sanitary trunk sewer systems serve approximately 50% of Toronto’s population
and carry sewage from almost 270 square kilometers to the Ashbridges Bay Treatment Plant (ABTP). A
significant part of the area (i.e. the “old City of Toronto”) is served by combined sewers.
A summary of the drainage area and population served by the tributary sewer system is provided in
Table ES3-1 below. While a small percentage of flows are intercepted by the North Toronto Treatment
Plant for treatment, the North Toronto Treatment Plant digested sludge and remaining sewer system flows
are routed to the Ashbridges Bay Treatment Plant (ABTP) for final treatment. The ABTP has a rated
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capacity of 818 MLD (9.47 m /s) based on the annual average daily flow.
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Table ES3-1 – Ashbridges Bay Treatment Plan Drainage Areas Populations
Trunk System
Don Trunk Sewershed
Waterfront Interceptor Sewershed
Total ABTP Sewershed
Area
(km2)
% Combined
Sewer Area
Residential
Population
2006
191
10%
739,583
76
84%
563,845
267
30%
1,303,428
ES-3.1 Don Sanitary Trunk Sewer System
The total area tributary to the Don Trunk System, Figure ES3-2, is approximately 191 km2, and consists of
six main trunks in the system:
1. Wilket Creek Sanitary Trunk Sewer.
2. West Don Sanitary Trunk Sewer.
3. East Don Sanitary Trunk Sewer.
4. North Toronto Sanitary Trunk Sewer.
5. Massey Creek Sanitary Trunk Sewer.
6. Coxwell Sanitary Trunk Sewer.
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Figure ES3-2: Total Area Tributary to the Don Sanitary Trunk Sewer System
Mid Toronto Interceptor
Low Level Interceptor
High Level Interceptor
The Don Sanitary Trunk sewer system, built in the 1950s, presently carries approximately 330 MLD
(3.82 m3/s) of the dry weather flow to ABTP. The trunk sewers generally follow the valleys of the Don
River and its tributaries which slope gently southward toward lake Ontario. At the downstream end of the
system, the Coxwell Sanitary Trunk Sewer receives sewage flows from four tributary trunk sewers: North
Toronto Sanitary Trunk Sewer, West Don Sanitary Trunk Sewer, East Don Sanitary Trunk Sewer, and
Massey Creek Sanitary Trunk; and conveys the flow to the ABTP by gravity.
The Coxwell Sanitary Trunk Sewer has been in service for approximately 50 years but it had not been
thoroughly inspected since the 1960s. Visual inspections at several manholes were made in 1985, but it is
very difficult to carry out detailed inspections because of the velocity of flow (1.5 m/s under DWF), its
significant depth below the ground surface (up to 40 m), and the distance between manholes (up to
1.5 km).
The status of the Coxwell Sanitary Trunk Sewer within the Don Sanitary Trunk Sewer System was of
concern and urgency because of its criticality and the lack of redundancy for security of operation and
maintenance requirements.
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ES-3.2 Waterfront Interceptor System
The total area tributary to the Waterfront Interceptor System, shown in Figure ES3-2 is approximately 76
km2, which presently contributes 450 MLD (5.21 m3/s) of sewage flow to ABTP. The Waterfront Interceptor
system consists of three major interceptors:
1. Low Level Interceptor (LLI).
2. High Level Interceptor (HLI).
3. Mid-Toronto Interceptor (MTI).
and two additional branches running east to west near the waterfront in the eastern part of the Study Area:
4. Lakefront Interceptor (LFI)
5. Queen Street Interceptor (QSI)
The local sewers in this system were designed as a combined system. Although an ongoing sewer
separation program has accomplished separation of approximately 80% for the road storm connections,
private properties have not been separated. Therefore, a significant quantity of wet weather inflow to the
combined sewers still exists from the roof downspout and foundation drain connections.
ES-3.3 North Toronto Treatment Plant
The sewershed tributary to the North Toronto Treatment Plant (NTTP) is approximately 31 km2, which
includes a mix of separated, partially separated, and combined sewers. About 70% of the area is serviced
3
with combined sewers. The NTTP has a rated capacity of 45 MLD (0.5 m /s). The inflow to the plant is
3
kept constant at approximately 35 to 45 MLD (0.4 to 0.5 m /s). Flows in excess of this amount are
conveyed for treatment at ABTP via the North Toronto Sanitary Trunk Sewer and the Coxwell Sanitary
Trunk Sewer. The digested sludge in the North Toronto Treatment Plant is pumped to the North Toronto
Sanitary Trunk Sewer from where it is conveyed to the ABTP for processing and disposal.
ES-3.4 Ashbridges Bay Treatment Plant
The ABTP has a rated primary treatment capacity of 2,532 MLD and a secondary treatment capacity of
818 MLD. From 2008 to 2010 annual average flows have been approximately 650 MLD and peak wet
weather flows can exceed 3,300 MLD. Secondary treatment is provided for peak wet weather flows up to
twice the rated capacity for short periods of time. Primary treatment with chlorine disinfection is provided
for wet weather flows in excess of the secondary treatment capacity.
ES-4.0 STUDY COMPONENTS
Due to the complexity of the Study, work was completed under three separate but related areas (DWF,
WWF storage and WWF treatment). The preferred solutions from each area were then integrated and
optimized to develop the Preferred Solution during Phase 2 of the study, and then, in Phase 3, a Preferred
Design Concept for the Integrated Preferred Solution was identified.
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The Don River and Central Waterfront Study Class Environmental Assessment therefore includes the
following components:
►
The investigation of the condition of the Don Trunk Sanitary Sewer System and Waterfront Interceptor
System including the condition of the flow control structures on these sewer systems.
►
The identification of possible system upgrades for the Don Trunk Sanitary Sewer System and
Waterfront Interceptor System to service existing dry weather flows and future growth up to 2031 in
accordance with the City’s current Official Plan.
►
The development of a Water Quality Model for the Don River and Inner Harbour.
►
The assessment of the impacts to the Don River of the North Toronto Treatment Plant and provision of
a recommendation for the future use of the existing treatment facility.
►
The confirmation of the final storage, configuration and design of the wet weather flow control systems
in the study area as identified in the City’s 2003 Wet Weather Flow Master Plan.
►
Identification and evaluation of alternative scenarios for the Don Trunk Sanitary Sewer System and
Waterfront Interceptor System including the size and location of system storage, the use of satellite
and/or centralized treatment facilities, trunk sanitary sewer system upgrades and the receiving water
quality improvements associated with each scenario.
►
The selection of a Preferred Solution following the Municipal Class EA process and taking into
consideration the results of consultation with the public and review agencies.
►
The provision of a Conceptual Design for the Preferred Solution and a strategy for the management of
the Don Trunk and Waterfront Interceptor Sanitary Sewer Systems during both dry and wet weather
conditions and for the treatment and release of stored wet weather flows.
Due to the complexity of the Study, work was completed under three separate but related areas and the
preferred solutions from each area were integrated and optimized to develop the Preferred Solution.
The three main areas of this Study, prior to the integration stage, are summarized as follows:
►
Dry Weather Flow;
►
Wet Weather Flow; and
►
Wet Weather Flow Treatment.
The City’s 2003 WWF MP had previously completed Phases 1 and 2 of the Municipal Class EA process
for the WWF capture, storage and treatment components at a strategic level. Consequently the Phase 2
evaluation for WWF did not repeat the previous evaluations. However, the Preferred Solution from the
City’s 2003 WWF MP was refined utilizing calibrated flow data and refined modelling. For the Dry Weather
Component, the current study addresses Phase 1 (Problem/Opportunity) and Phase 2 (Alternative
Solutions). The current study then addresses Phase 3 (Alternative Design Concepts for the Preferred
Solutions) and Phase 4 (Environmental Study Report) for all components. For the dry weather component,
alternative solutions were developed and evaluated to identify which one(s) would give the most benefits
with the least negative impacts at the most reasonable cost. The solutions for each of the three
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components were then evaluated alongside each other to see if there were opportunities for one solution
to serve more than one purpose to gain additional benefit.
ES-5.0 OVERVIEW OF STUDY APPROACH
This EA brings together three separate, yet interconnected components:
►
Dry Weather Flow Component (dealing with the upgrades to the sanitary trunk sewer system for
improved operations and future growth)
►
Wet Weather Flow Component (dealing with capturing and storing combined sewer overflows
(CSOs)
►
Wet Weather Treatment Component (dealing with the treatment of stored CSOs)
The Study Approach is illustrated in Figure ES5-1.
Figure ES5-1: Study Approach
PREFERRED
SOLUTION
SYSTEM OPTIMIZATION
and Design Concepts
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An important part of this Class EA was to look for opportunities to integrate, or bring together, the three
streams of activity. For example, it is possible to consider one piece of infrastructure for multiple uses,
therefore minimizing impacts and potentially costs.
ES-6.0 OTHER RELATED REPORTS AND STUDIES
The study area is large and there are many ongoing activities or planned projects. The Study Team
reviewed previous studies, current policies and activities, and coordinated with relevant departments and
agencies to understand how this project could fit with and compliment these other activities. A number of
studies of note, provide the foundation for this EA.
ES-6.1 The Wet Weather Flow Master Plan (2003)
The City of Toronto completed and approved the Wet Weather Flow Master Plan (WWF MP) in 2003. It
was a large-scale and broad-based Master Plan that addressed Phases 1 and 2 of the Municipal Class EA
process for stormwater and combined sewer overflow control and treatment projects at a strategic level.
The WWF MP is a long-term (100-year) plan aimed to protect the environment and sustain healthy rivers,
streams and other water bodies by reducing and ultimately eliminating the adverse effects of Wet Weather
Flow (WWF). The WWF MP 25-Year Implementation Plan was prepared to guide implementation of the
priority programs and projects over the first quarter century. To date, a number of projects have been
initiated and/or completed (City of Toronto, 2009) including:
►
The Coatsworth Cut Stormwater Treatment Wetland and CSO Outfalls Control Municipal Class EA,
►
Eastern Beaches Storm Sewer Outfalls Control Municipal Class EA
►
The Scarborough CSO Municipal Class EA.
►
Construction of the Earl Bales Park Stormwater Management Facility which treats runoff from 550
hectares of existing development before discharging to the West Don River.
ES-6.2 Don Trunk Sanitary Sewer System Improvements
Environmental Study Report (1991)
The 1991 Don Trunk Sanitary Sewer System Improvements Environmental Study Report proposed new
trunk sewers as alternatives for the Don Sanitary Trunk System. The objective of the 1991 study was to
determine the existing flow commitments and future needs for the purpose of water pollution control
planning and to reduce combined sewer overflows resulting from stormwater infiltration and inflow. The
conclusions of the study included the following:
►
Measured flows during wet weather periods indicated that some of the sewers reach capacity during
relatively frequent storm events.
►
Analysis of data collected between April-October of 1982 indicated there were 28 to 54 combined
3
sewer overflows and the overflow volume at the various regulators ranged from 24,000 m to
3
385,000 m .
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►
Analysis of the measured flows indicated the sewershed had reached a mature state of development,
as the sewers had generally reached the capacity for which they were designed.
The 1991 ESR was completed, but not submitted to the MOE. The current study takes into account the
results of this work.
ES-6.3 Ashbridges Bay Treatment Plant (ABTP) EA
The City completed an Individual Environmental Assessment in 1997 that planned for a new outfall, and at
the time, identified ultraviolet disinfection (UV) as the preferred technology for disinfection of the secondary
effluent. Since that time, technologies, energy and materials costs have changed, and as due diligence,
the City reviewed alternatives to confirm the best approach to providing disinfection of secondary effluent
and primary effluent bypasses. To this end, the future ABTP outfall and disinfection system
(chlorination/dechlorination) has been EA approved and the design is being finalized. It was considered for
joint use for any WWF satellite treatment plant in the vicinity of the ABTP.
ES-6.4 Future of the North Toronto Treatment Plant
The future of the North Toronto Treatment Plant (NTTP) was examined in 1995 through the Environmental
Assessment for the ABTP (Future of the North Toronto Treatment Plant). Four alternative scenarios were
considered for the NTTP:
►
Alternative A: Upgrade the NTTP to meet Provincial Water Quality Objectives (PWQOs) and treat
maximum of 40 ML/d.
►
Alternative B: Expand the NTTP (treat maximum of 95 ML/d).
►
Alternative C: Divert flows to the ABTP and either:
►
Decommission the NTTP, or
►
Maintain the NTTP for future use in combined sewer overflow or stormwater-management; and
►
Alternative D: Do Nothing (treat maximum of 40 ML/d).
Alternative "C" was recommended as the preferred alternative subject to capacity being available at the
ABTP and in the Don Trunk Sewer system, and mitigation of resulting environment impacts in the Lower
Don River, otherwise, Alternative "A" would become the preferred alternative.
The current study considered three alternative scenarios part of an investigation of the future of the North
Toronto Treatment Plant.
►
The Do-Nothing (i.e. Maintain and Operate NTTP as now)
►
Decommission the NTTP
►
The third scenario evaluated two upgrade options to the NTTP to reduce impacts of ammonia and
phosphorous on the Don River. The first option looked at extensive upgrades to achieve the lowest
concentrations of these parameters in the effluent using best available technologies. The second
option considered modest upgrades to effluent quality through dual point chemical addition for
phosphorous removal and enhanced nitrification using existing infrastructure.
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The evaluation identified that the plant should be retained with modest upgrades to improve effluent as it
avoids an expansion to the ABTP while enhancing downstream water quality and is no longer subject to
further analysis in the EA.
ES-7.0 PREFERRED DESIGN
Based on the extensive research and analysis, input from the public, agencies and other stakeholders, the
preferred solution and the preferred design for the Project has been finalized and is shown on Figure ES71. The “integrated solution” addresses wet weather flow controls and sanitary servicing needs in one
complete system. The preferred design includes the following components:
Dry Weather Flow: Sanitary Trunk Sewer System
►
The Lower Don/Coxwell Bypass Tunnel will be used on a contingency basis as a bypass to the
existing Coxwell Sanitary Trunk Sewer allowing for periodic maintenance and any necessary repairs of
the Coxwell STS;
►
Four underground storage tanks for offline storage of peak sanitary flows where additional capacity is
needed; and
►
Upgrades to the North Toronto Treatment Plant (NTTP).
Wet Weather Flow Collection and Storage System
►
Three interconnected tunnels connected to the equivalent of 15 underground vertical storage shafts
(30 metres in diameter) will collect and store combined sewer overflows and convey these flows to a
new wet weather flow treatment facility;
►
Three tunnels include the Lower Don Tunnel/Coxwell Bypass (10.8 km); Taylor Massey Creek Tunnel
(6.0 km); and Inner Harbour Tunnel (5.5 km); and
►
Three underground storage tanks for offline storage of combined sewer overflows from 4 remote
outfall locations.
Treatment of Collected Wet Weather Flow
►
A new wet weather treatment facility will provide high-rate treatment of wet weather flows and will be
located on future lakefill in the waterlot south of the Ashbridges Bay Treatment Plant;
►
A new pumping station in Ashbridges Grove Park with forcemains connecting to the new wet weather
flow treatment facility; and
►
Upgrade of an existing CSO tank at the North Toronto Treatment Plant.
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Figure ES7-1: Preferred Solution
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ES-8.0 BENEFITS OF THE PREFERRED SOLUTION
The implementation of this project will improve both the sanitary trunk sewer system and our environment.
Sanitary Trunk Sewer benefits include:
►
Construction of the Coxwell Sanitary Trunk Sewer (STS) bypass to provide redundancy and to allow
for periodic maintenance and ensure safe, ongoing operation of the Coxwell STS.
►
Upgrading the City's critical Don Sanitary Trunk Sewer system to ensure the system has capacity to
effectively service future population growth in the study area.
Controlling wet weather flows will achieve the following benefits:
►
Virtually eliminate untreated sewage (from CSOs) from entering the Don River, Taylor-Massey Creek
and Central Waterfront through the capture and treatment of flows. This will reduce releases of
pathogens and pollutants to waterways, leading to improvements in water quality, enhanced
recreational opportunities, and improved aquatic habitat. For example, the level of bacterial
contamination in the Inner Harbour would drop sufficiently that over 80% of its area would eventually
meet the “Blue Flag” swimming standard. This compares to less than 10% of its area under present
and future conditions if the project is not implemented. As shown in Figure ES8-1, the “blue” area
covers the majority of the harbor after project implementation with only the area immediately adjacent
to the mouth of the Don River still falling below the Blue Flag standard.
Figure ES8-1: Comparison of Swimmability of Inner Harbour Before and After Project
Before
After
The water quality in the lower Don River itself would be significantly improved but the benefits would
be somewhat masked by pollutants flowing in from upstream. Once the complete program of
stormwater and CSO controls proposed in the 2003 WWF MP are improved, the real benefits of the
CSO controls proposed in this project on the health of the Don River would be evident.
►
Help reduce the "flashy" inputs of combined sewer overflows, which contribute to stream erosion and
possible flooding.
►
Support revitalization efforts for Toronto's waterfront.
►
Ultimately move us closer to delisting the City of Toronto as a polluted Area of Concern in the Great
Lakes Basin.
►
Ensure the City meets Provincial requirements for the control of combined sewer overflows, and
support commitments made by Federal and Provincial Governments, for the cleanup of the Areas of
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Concern through the Canada-Ontario Agreement and Federal Government’s commitment through the
Bi-National Great Lakes Water Quality Agreement.
By bringing together the projected sanitary trunk sewer servicing needs with the wet weather flow control
requirements as a complete and integrated system, all of the benefits of the Project will be achieved at a
reduced cost.
ES-9.0 STAKEHOLDER CONSULTATION
Throughout the study process, extensive consultation has taken place with interested and/or affected
members of the public, residents’ associations, environmental groups, and other stakeholders. Meetings
and briefings have also been held with City Councillors, City Agencies, Boards and Commissions and
Divisions including Parks, Forestry & Recreation, Transportation, City Planning, the Toronto and Region
Conservation Authority (TRCA), Toronto Transit Commission, Public Health and Waterfront Toronto,
among others. Meetings with review agencies such as the Ministry of the Environment, Ministry of Natural
Resources, Department of Fisheries & Oceans, and Environment Canada have also taken place. Finally,
First Nations have been engaged through correspondence and meetings at various phases of the study.
Consultation and communications activities have included:
►
Four rounds of Public Information Centres (nine open houses
in total from 2008 to 2011) and other consultation events
(e.g., workshop and public forum in 2010) were held at
various stages of the EA study process to receive input on the
problem/opportunity, the preferred solution, and the preferred
design.
►
Meetings and briefings with community groups, ratepayers
associations, environmental groups and individuals.
►
Project display booths at various locations and events, such as local malls and Lake Ontario Evenings
hosted by the TRCA.
►
Project postcards and newsletters, as well as a project video and website
(www.toronto.ca/involved/projects/cleanwaterways) to raise awareness and provide information to the
public.
ES-10.0 ADDRESSING KEY ISSUES
While the Project and the objectives of cleaning up the Don River and Central Waterfront has received
strong support from a broad range of stakeholders throughout the consultation process, some
issues/concerns have been raised about the preferred solution and recommended siting of specific
components of the Project. The Project Team has considered the input received from the public, other
stakeholders and agencies throughout the consultation process, including input about characterization of
the problem/opportunity, how people wanted to be consulted, developing a list of alternative solutions and
how they would be evaluated, developing and finalizing the preferred design. This input has played a
significant role in finalizing the preferred solution and design for the Project.
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ES-10.1 Comments about the Preferred Design
Input about how alternative solutions were evaluated shaped the process that was undertaken.
The preferred design identified in the Don River and Central Waterfront Class EA study confirms the
approach to addressing CSOs in the Don watershed that was recommended in the Wet Weather Flow
Master Plan and adopted by City Council in 2003 – namely a system of tunnels, storage elements and
treatment to capture and treat CSOs. However, some stakeholders have advocated for the elimination of
CSOs by completely separating the existing combined sewer system (i.e. by constructing road storm
sewers separating this stormwater flow from the sanitary flow) rather than implementing a tunnel storage
and treatment system to capture and treat the CSOs.
Sewer separation is an approach that has been examined by the City and has not been recommended due
to technical and cost considerations, in addition to the fact that it does not achieve the water quality
benefits and solve the environmental problems caused by polluted stormwater entering our waterways. In
short, it does not provide an effective solution to the problem.
From a technical perspective, the City cannot completely separate stormwater flow from sanitary flow. The
City can, at a significant cost, build new storm sewers parallel to existing combined sewers however this
would not stop stormwater from entering into the combined sewer system because of direct connections
from private properties (e.g. foundation drains). Even with mandatory downspout disconnection, it is not
possible to remove all storm inflow from private drainage systems.
Most importantly, sewer separation, by itself, will not achieve the necessary water quality improvements as
stormwater runoff contains high concentrations of pollutants, well in excess of Provincial Water Quality
Objectives, and it is therefore necessary to capture and treat stormwater rather than have it released
untreated into our waterways. This is consistent with stormwater management planning for new
development across Ontario. This conclusion was reached in the original Remedial Action Plan reports of
the 1990’s and reconfirmed through the extensive analysis carried out for the WWFMP.
Some participants have also requested greater focus be placed on green solutions and waterway
restoration. The City is undertaking a comprehensive program of source controls, green infrastructure and
waterway rehabilitation, as identified within the WWF MP, through other initiatives, as possible. This
continues to be an overall focus for Toronto Water.
ES-10.2 Comments about the Siting of Project Components
Many sites within the study area were considered for locating the various project elements, including
underground vertical storage shafts, offline tanks and the wet weather flow treatment facility. The Study
Team worked closely with Parks, Forestry and Recreation, Transportation, Planning, and the TRCA to
evaluate the sites and identify preferred locations based on technical (e.g., constructability, hydraulics),
social (e.g., land use and community disruption) and natural environment considerations (e.g., minimizing
impacts to vegetation).
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Based on the aforementioned criteria, the recommended study design has identified preferred siting
locations for project components which are generally on City owned land, have as little impact on existing
land uses as possible and are located primarily in open areas in the Don Valley or in passive parks or
open green areas. Efforts were also made to avoid sites adjacent to homes wherever possible.
Along the Central Waterfront, three locations were initially recommended for the siting of underground
vertical storage shafts – Little Norway Park, a parking lot at Rees Street and Queens Quay and the York
Street off-ramp site at Queens Quay. Based on feedback received during the June 2011 public
consultation concerning potential incompatibility with future land uses and community disruption to local
residents and businesses, the preferred design was re-evaluated. The proposed underground vertical
storage shafts in the Harbourfront area were moved to the Keating Railyard near the mouth of the Don
River. Only one temporary construction shaft (Rees Street parking lot at Queens Quay) is now proposed to
facilitate the construction and future maintenance of the wet weather flow tunnel along the Inner Harbour.
For underground offline storage tanks that are recommended to be sited in passive parks or open green
areas, closer to residential homes (e.g., Farlinger Park), it is recognized that there will be some disruption
and that this is of concern to residents. The locations were chosen to be close to the CSOs and to
effectively capture the flows. Construction impacts were also of concern. Mitigation measures will be
taken at all sites to minimize construction impacts to the greatest extent possible.
Toronto Water will continue to consult with local communities, City Parks, Forestry and Recreation and/or
TRCA (for project sites within TRCA regulated areas) during detailed design on the design of above
ground features (e.g., venting units, access grates), as well as restoration and site enhancement
opportunities at these locations.
Additional details about the consultation program and the input received can be found in Chapter 7 of the
main report.
ES-11.0 IMPLEMENTATION TIMEFRAME AND COSTS
It is proposed that project implementation will be completed in phases, with the initial phase of
implementation focused on providing redundancy and security of operation for the Coxwell Sanitary Trunk
Sewer and meeting minimum Provincial requirements for CSO control. Over the proposed 25-year
implementation timeframe for the Project, additional elements would be constructed to achieve significant
water quality improvements and environmental benefits beyond those currently required by the Province.
Table ES11-1 presents the proposed implementation plan with associated costs.
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Table ES11-1 - Don River & Central Waterfront Project Proposed Implementation Timeframe/Costs
Stage
Schedule
Cost
Stage 1 Coxwell Bypass and Pumping Station
Years 1-10
$301M
Stage 2 TM and RTC to meet MOE’s F-5-5
Years 6-15
$203M
Stage 3 DWF and WWF Tanks
Years 11-15
$109M
Stage 4 IHW and Vertical Storage in LD/IHE for 1-CSO
control
Years 11-25
$850M
TOTAL
$1.463B
ES-12.0 NEXT STEPS
Upon finalization of the ESR, a Notice of Completion (to be circulated in local newspapers across the
Study Area and sent to the Project contact list) and the ESR will be filed with the Ontario Ministry of the
Environment for the required 30-day public review period.
Subject to approval by the Ontario Ministry of the Environment, and funding approval, through Toronto
Water’s Capital Budget, it is anticipated that the design of Phase I, which addresses the critical twinning of
the Coxwell Sanitary Trunk Sewer, will begin in 2012/13.
ES-13.0 ACKNOWLEDGEMENTS
The preparation of this ESR required significant input and commitment from a large number of individuals,
and organizations. Acknowledgements and thanks are extended, in particular, to staff from:
►
City of Toronto Water
►
City of Toronto Parks, Forests and Recreation
►
MMM Group
►
BPR-CSO
►
Golder Associates
►
Andrews Infrastructure
►
Archaeoworks Inc.
►
EMA Canada Inc.
►
Unterman McPhail Associates
►
Shoreplan Engineering Limited
►
Ehl Harrison Consulting Inc.
►
TRCA
The input from the public and numerous resident and environmental groups is also acknowledged and
appreciated.
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