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F i n a l R e p o r t

Municipal Class Environmental Assessment

Environmental Study Report

Investigation of Chronic Basement Flooding – Study Area 3

Prepared for

City of Toronto

January 2011

Prepared by

Contents

1. Introduction ........................................................................................................................ 1-1 1.1 Background .............................................................................................................. 1-1 1.2 Study Justification ................................................................................................... 1-5 1.3 Municipal Class EA Process .................................................................................. 1-5 1.4 Stakeholder Involvement ....................................................................................... 1-6

2. Problem Statement ............................................................................................................ 2-1 2.1 Project Justification ................................................................................................. 2-1 2.2 Objectives ................................................................................................................. 2-2 2.3 Methodology ........................................................................................................... 2-2

3. Existing Conditions ........................................................................................................... 3-1 3.1 Socio Economic Environment ............................................................................... 3-1

3.1.1 Land Use .................................................................................................... 3-1 3.1.2 Archaeological Assessment ..................................................................... 3-2

3.2 Natural Environment ............................................................................................. 3-2 3.3 Technical Environment/Information .................................................................. 3-4

3.3.1 Sewer System ............................................................................................. 3-4 3.3.2 Major System ............................................................................................. 3-9 3.3.3 Historical Development of the Area ...................................................... 3-9 3.3.4 Previous Studies and Improvement ....................................................... 3-9 3.3.5 Sewer Use By-Law at the time of Construction .................................. 3-10 3.3.6 Historical Basement Flooding ............................................................... 3-13 3.3.7 Rainfall Data ............................................................................................ 3-14 3.3.8 Flow Monitoring Data ............................................................................ 3-14 3.3.9 Field Data and Information ................................................................... 3-21 3.3.10 Desktop Geological Assessment ........................................................... 3-21

4. Model Development ......................................................................................................... 4-1 4.1 Existing Data ........................................................................................................... 4-1 4.2 InfoWorks Model .................................................................................................... 4-1

4.2.1 Model Set Up ............................................................................................. 4-1 4.2.2 Model Calibration ..................................................................................... 4-2

5. Assessment of Existing Systems ..................................................................................... 5-1 5.1 Flood Criteria .......................................................................................................... 5-1 5.2 Water Quality Criteria ........................................................................................... 5-3 5.3 Assessment of Existing Systems ........................................................................... 5-4

5.3.1 Simulation of Design Storm and Historic Events ................................ 5-4 5.3.2 Potential Flooding Identification ............................................................ 5-4

6. Solution Development ..................................................................................................... 6-1 6.1 Solution Development ........................................................................................... 6-1

6.1.1 Cluster Approach ..................................................................................... 6-1

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CONTENTS, CONTINUED

6.1.2 Holistic Approach ..................................................................................... 6-1 6.1.3 Approach Comparison ............................................................................. 6-1

6.2 Source Controls ....................................................................................................... 6-2 6.2.1 Downspout Disconnection Program ...................................................... 6-2

6.3 Conveyance Controls .............................................................................................. 6-3 6.3.1 Flow Balancing .......................................................................................... 6-4 6.3.2 Storm Water Conveyance System ......................................................... 6-13

6.4 End of Pipe Control ............................................................................................... 6-14 6.4.1 CSO Tanks ................................................................................................ 6-14 6.4.2 Additional Storage .................................................................................. 6-15

6.5 CSO Analysis ......................................................................................................... 6-15

7. CSO Tank Alternative Analysis ...................................................................................... 7-1

8. Recommended Solutions .................................................................................................. 8-1 8.1 Recommended Solutions ........................................................................................ 8-1

8.1.1 Sub-Area 1 .................................................................................................. 8-1 8.1.2 Sub-Area 2 .................................................................................................. 8-1 8.1.3 Sub-Area 3 .................................................................................................. 8-1 8.1.4 Sub-Area 4 .................................................................................................. 8-2 8.1.5 Sub-Area 5 .................................................................................................. 8-2 8.1.6 Sub-Area 6 .................................................................................................. 8-2 8.1.7 Sub-Area 7 .................................................................................................. 8-2 8.1.8 Sub-Area 8 .................................................................................................. 8-2

8.2 Cost Estimate ........................................................................................................... 8-3 8.3 Coordination during Detailed Design .................................................................. 8-3 8.4 Impacts and Mitigation .......................................................................................... 8-4

8.4.1 Potential Impacts and Mitigation Measures of Construction during Construction ............................................................................................................ 8-4 8.4.2 Potential Impacts and Mitigation Measures during Operation .......... 8-7

9. Consultation Program ....................................................................................................... 9-1 9.1 Public and Agency Consultation .......................................................................... 9-1

9.1.1 Public Notification .................................................................................... 9-2 9.1.2 Agency Notification .................................................................................. 9-3

9.2 Public Open House ................................................................................................. 9-3 9.2.1 Public Open House #1 .............................................................................. 9-3 9.2.2 Public Open House #2 .............................................................................. 9-4

9.3 Councillor Briefings ................................................................................................ 9-5 9.4 Notice of Completion .............................................................................................. 9-5

Tables 3-1 Land Use Classification ..................................................................................................... 3-1 3-2 Summary of Parks and Green Spaces Based on Air Photos ......................................... 3-3 3-3 Summaries of System Data ............................................................................................... 3-4 3-4 Summary of Historical and/or Chronic Basement Flooding in Study Area 3 ........ 3-13 3-5 Average Dry Weather Flow ............................................................................................ 3-15 4-1 InfoWorks CS Model Calibration Parameters................................................................ 4-3

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CONTENTS, CONTINUED

4-2 InfoWorks CS Model Calibration Parameters with Estimated Runoff Coefficient Value ............................................................................................................... 4-5

5-1 Existing System Typical Year Performance .................................................................... 5-3 5-2 Summary of Causes of Basement Flooding by Sub-Area ............................................. 5-5 5-3 Primary Causes of Basement Flooding in Each Sub-Area by Street Name

(100 year design storm) ...................................................................................................... 5-5 6-1 Comparison of Cluster versus Holistic Approach ......................................................... 6-2 6-2 Existing Condition and 75% Roof Disconnected Potential Flooding Properties ....... 6-3 6-3 Summary of Proposed Inlet Control Devices (ICDs) and Sealed Catch Basins

based on the 1:100-Year Storm .......................................................................................... 6-5 6-4 Summary of Proposed New Catchbasins and Peak flows based on

1:100-Year Storm ................................................................................................................. 6-9 6-5 Summary of Alignment Analysis ................................................................................... 6-13 6-6 Proposed Collector Storm Sewer Summary for the Entire Study Area .................... 6-14 6-7 CSO Summary................................................................................................................... 6-16 7-1 Detailed Evaluation of Alternative for Fairbank Memorial Park ................................ 7-5 7-2 Detailed Evaluation of Alternative for Nairn Park ...................................................... 7-10 8-1 Cost Estimate Summary .................................................................................................... 8-3 8-2 Potential Impacts and Mitigation Measures during Construction .............................. 8-5 8-3 Potential Impacts and Mitigation Measures during Operation ................................... 8-7 9-1 Summary of Consultation Plan ........................................................................................ 9-1 Figures 1-1 Study Area Map .................................................................................................................. 1-3 1-2 Municipal Class Environmental Assessment Planning and Design Process ............. 1-7 3-1 Land Use Classification ..................................................................................................... 3-5 3-2 Area 3 Combined and Sanitary Sewer System ............................................................... 3-6 3-3 Area 3 Storm Sewer System .............................................................................................. 3-7 3-4 Major System Overland Flow Path ................................................................................ 3-11 3-5 Historical Basement Flooding Reported ....................................................................... 3-17 3-6 Cluster Areas Based on Historical and/or Chronic Basement Flooding .................. 3-18 3-7 Rain Gauge and Flow Monitoring Location ................................................................. 3-19 3-8 Field Survey Results – Downspout Connectivity ........................................................ 3-23 3-9 Field Survey Results – Reverse Driveways ................................................................... 3-24 3-10 Field Survey Results – Catchbasin Type ....................................................................... 3-25 5-1 Flood Criteria ...................................................................................................................... 5-2 5-2 CSO Locations ..................................................................................................................... 5-9 5-3 Existing Condition Sewer System – Dry Weather Flow ............................................. 5-10 5-4 Existing Condition Minor Sewer System – 2-Year Design Storm .............................. 5-11 5-5 Existing Condition Minor Sewer System – 5-Year Design Storm .............................. 5-12 5-6 Existing Condition Minor Sewer System – 100-Year Design Storm .......................... 5-13 5-7 Existing Condition Minor Sewer System – May 12, 2000 Historical Storm ............. 5-14 5-8 Existing Condition Major System – 2-Year Design Storm .......................................... 5-15 5-9 Existing Condition Major System – 5-Year Design Storm .......................................... 5-16 5-10 Existing Condition Major System – 100-Year Design Storm ...................................... 5-17 5-11 Existing Condition Major System – May 12, 2000 Historical Storm .......................... 5-18

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CONTENTS, CONTINUED

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5-12 Existing Condition Minor Sewer System Flooding Potential for 100-Year Design Storm .................................................................................................................... 5-19

5-13 Existing Condition Major System Flooding Potential for 100-Year Design Storm 5-20

6-1 Location of ICD and Sealed Catchbasins ........................................................................ 6-7 6-2 Location of Proposed Catchbasins – Inlet Capacity Based on Each Location ......... 6-11 6-3 Location of proposed Storm Sewers, Sanitary Sewer and Storm Tunnel ................ 6-12 7-1 Fairbanks Memorial Park – Alternative 1 ....................................................................... 7-2 7-2 Fairbanks Memorial Park – Alternative 2 ....................................................................... 7-3 7-3 Fairbanks Memorial Park – Alternative 3 ....................................................................... 7-4 7-4 Location of CSO Tank – Fairbank Memorial Park Preferred Location....................... 7-6 7-5 Nairn Park – Alternative 1 ................................................................................................ 7-8 7-6 Nairn Park – Alternative 2 ................................................................................................ 7-9 7-7 Location of CSO Tank – Nairn Park Preferred Location ............................................ 7-10 8-1 Preferred Key Solution Map ............................................................................................. 8-9 8-2 Sub – Area 1 Recommended Solution ........................................................................... 8-10 8-3 Sub – Area 2 Recommended Solution ........................................................................... 8-11 8-4 Sub – Area 3 Recommended Solution ........................................................................... 8-12 8-5 Sub – Area 4 Recommended Solution ........................................................................... 8-13 8-6 Sub – Area 5 Recommended Solution ........................................................................... 8-14 8-7 Sub – Area 6 Recommended Solution ........................................................................... 8-15 8-8 Sub – Area 7 Recommended Solution ........................................................................... 8-16 8-9 Sub – Area 8 Recommended Solution ........................................................................... 8-17 Appendixes A Municipal Class Environmental Assessment Process B Archaeological Stage 1 Investigation Report C Natural Environmental Investigation Reports D Modelling Technical Memorandum E Geotechnical Desktop Review Study Report F Public and Agency Consultation G Cost Estimate

1. Introduction

1.1 Background Urban development has altered the natural way in which stormwater finds its way back to creeks, rivers and Lake Ontario. During wet weather events, stormwater in the form of rain or snow travels along the City’s streets collecting dirt, oil, grease and other pollutants before entering the sewer system. This results in degraded water quality conditions and can lead to the erosion of our ravines, combined sewer overflow (CSO) events, basement flooding and beach closures.

The City of Toronto (City) is undertaking a Municipal Class Environmental Assessment (Class EA) to assess causes of basement flooding in the former Cities of North York, York, Etobicoke, Scarborough, and the Borough of East York; develop solutions to control flooding impacts. Based on recent past storm events, a total of 32 flooding areas have been identified across the City. This Schedule C Class EA study will focus on Study Area 3 (Study Area) within the former City of York. Figure 1-1 illustrates the Area 3 Study boundary, and the major and minor system boundaries.

Like many cities established before 1900, the City of Toronto’s first developed sewers carried both wastewater and stormwater runoff that went directly to the receiving waters through large collector sewers. As the City grew, there was not enough water in the rivers and Lake to dilute the wastewater. The City built sewage treatment plants and during dry weather directed the flows from the combined sewers to these plants for treatment. During rainfall or snowmelt, the volume of water occasionally exceeded the treatment plant’s capacity and some of the water overflowed into Lake Ontario. Since 1960, no new combined sewers have been permitted and stormwater runoff and wastewater are carried in separate pipes. In the early 1960s until the mid 1980s, the City underwent a road sewer separation project. Study Area 3 was primarily built in the 1950s. Therefore, the sewershed consists of combined and partially separated sewers. The combined sewers occasionally lead to combined sewer overflow (CSO) events during wet weather conditions. A CSO event occurs during wet weather when the combined sewer cannot convey all of the stormwater and wastewater to the Humber Wastewater Treatment Plant, overflowing the dilute stormwater and wastewater to local rivers and eventually Lake Ontario.

The Study Area is generally bounded by Black Creek Drive and Weston Road to the west and Dufferin Street and Vaughan Road to the east. The study area extends north of Castlefield Avenue, a little beyond the east-west railway line section, and is bounded by Rogers Road to the south.

Land use within the Study Area is composed of various land uses such as residential, employment areas, and green spaces according to maps in the City’s Official Plan. Black Creek Drive is the major watercourse within the Study Area.

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0BINTRODUCTION

FIGURE 1-1 Study Area Map

Figure located in folder on CD provided named EA_Report_Figures.


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1.2 Study Justification In August 2005, the City received a record amount of rainfall that resulted in widespread complaints as a result of surface and basement flooding. In April 2006, City Council (Council) responded and approved a comprehensive work plan composed of the following scope of work activities for chronic basement flooding areas:

• Sewer inspection to identify problems in the sanitary sewer system (such as blockages) and sources of extraneous stormwater (such as deteriorated pipes and maintenance holes and illicit catchbasin connections or roof leader connections) for corrective action.

• Targeted implementation of the City’s Downspout Disconnection Program.

• Engineering assessments of stormwater overland flow routing and evaluation of options to reduce or eliminate severe ponding on streets during extreme storm conditions.

• Engineering assessments of the storm sewer and sanitary sewer systems to reduce stormwater inputs and identify and evaluate options to reduce or eliminate hydraulic bottlenecks to alleviate basement flooding during extreme storm conditions.

A total of 32 chronic basement flooding areas were identified in the work plan. The following level-of-service criteria were approved by Council:

• A storm event equivalent to the May 12, 2000 storm be adopted as the enhanced level of protection against basement flooding from sanitary sewer backup in areas of the City experiencing chronic basement flooding

• The 100-year storm be adopted for the City as the level of protection, where feasible, against surface flooding from ponding on the street, in areas of the City experiencing chronic basement flooding where a proper major (overland flow) stormwater drainage system does not exist

1.3 Municipal Class EA Process The approved Class EA document prepared by the Municipal Engineer’s Association (MEA) in June 2000 documents an approved Class EA process. There are five phases of assessment in the Class EA document:

• Phase 1: Definition of the Problem

• Phase 2: Identification and Assessment of Alternative Solutions and Selection of a Preferred Solution

• Phase 3: Identification and Assessment of Alternative Sites/Design Concepts and Selection of a Preferred Site/Design

• Phase 4: Preparation of an Environmental Study Report (ESR)

• Phase 5: Implementation


0BINTRODUCTION


The Class EA document places projects into three possible schedules based on their characteristics (referred to as Schedule A, B, or C projects). The schedule under which a project falls determines the planning and design phases that must be followed.

Schedule A projects are minor operational and upgrade activities and can proceed without further assessment once Phase 1 of the Class EA process is complete (that is, the problem is reviewed and a solution is confirmed).

Schedule B projects must proceed through the first two phases of the process. Proponents must identify and assess alternative solutions to the problem, inventory impacts, and select a preferred solution. They must also contact relevant agencies and affected members of the public. Provided that no significant impacts are found and no requests are received to elevate the project to Schedule C or undertake the project as an Individual Environmental Assessment (IEA) (Part II Order), the project may proceed to detailed design (Phase 5).

Schedule C projects require more detailed study, public consultation, and documentation as they may have more significant impacts. Projects categorized as Schedule C must proceed through all five phases of assessment. An ESR must be completed and made available for a 30-day public review period prior to proceeding to project implementation (Phase 5).

In the event that there are major issues that cannot be resolved upon completion of the report, individuals may request the Ministry of Environment (MOE) to require the proponent to comply with Part II of the EA Act. Upon receiving a Part II Order request, the MOE reviews the request and study information and can make one of the following decisions: deny the request, refer the matter to mediation, or require completion of an IEA. The MOE considers a number of factors in making decisions, including the adequacy of the planning process, the potential for significant adverse environmental effects after mitigation measures are considered, the participation of the requester in the planning process, and the nature of the request.

The planning and design process for Schedule C Class EA projects is being followed for Study Area 3, including an extensive public consultation program that goes well beyond the statutory requirements.

A detailed description of the EA process is provided in the Appendix A.

1.4 Stakeholder Involvement Stakeholder involvement and consultation is a key feature in the Class EA process. An effective consultation process provides the opportunity to exchange information and ideas with stakeholders. There are mandatory points of consultation for the various project schedules in the Class EA process. Consultation for a Schedule C project include the notice of commencement, one mandatory public meeting with the option to hold a second discretionary public meeting, notice of completion, and a 30-day review period to solicit comments from public and review agencies.

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FIGURE 1-2 Municipal Class Environmental Assessment Planning and Design Process

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ENVIRONMENTALSTUDY REPORT

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IMPLEMENTATION

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KWO-02-193

MunicipalEngineersAssociation


2. Problem Statement

This section outlines the problem statement for the proposed EA. Phase 1 of the five-phase Class EA planning process requires proponents to document factors indicating that the improvement is needed, and to develop a clear statement of the identified problem to be investigated. Phase 2 requires a thorough evaluation of the planning options or alternative solutions to the problem.

The problem statement is the starting point in undertaking a Class EA, becomes the central integrating element of the project, and helps to define the project scope. The information considered in the development of the problem statement is presented in Section 2.1.

2.1 Project Justification In August 2005, the City received a record amount of rainfall that resulted in widespread complaints from constituents as a result of surface and basement flooding. In Study Area 3 the May 12, 2000 storm event resulted in more complaints than the August 5, 2005 storm event. Although storm events are not evenly distributed across the City the May 12 event in Study Area 3 was equivalent to a 1 in 25 year storm event. In April 2006, Toronto City Council responded and approved a comprehensive work plan composed of the following scope of work for chronic basement flooding areas:

• Sewer inspection to identify problems in the sanitary sewer system (such as blockages) and sources of extraneous stormwater (such as deteriorated pipes and maintenance holes and illicit catchbasin connections or roof leader connections) for corrective action

• Targeted implementation of the City’s Downspout Disconnection Program

• Engineering assessments of stormwater overland flow routing and evaluation of options to reduce or eliminate severe ponding on streets during extreme storm conditions

• Engineering assessments of the storm sewer and sanitary sewer systems to reduce stormwater inputs and identify and evaluate options to reduce or eliminate hydraulic bottlenecks to alleviate basement flooding during extreme storm conditions

Thirty-two chronic basement flooding areas were identified, mainly across the former North York and Scarborough districts, as Area 3 in the work plan. The following level-of-service criteria were approved by Council:

• A storm event equivalent to the May 12, 2000 storm be adopted as the enhanced level of protection against basement flooding from sanitary sewer backup in areas of the City experiencing chronic basement flooding

• The 100-year storm be adopted for the City as the level of protection, where feasible, against surface flooding from ponding on the street, in areas of the City experiencing chronic basement flooding where a proper major (overland flow) stormwater drainage system does not exist


1BPROBLEM STATEMENT

Wet weather flow contributes to the degradation of the City’s watersheds and the near-shore zone of Lake Ontario environments. Urban development has altered the natural hydrologic process such that wet weather runoff volumes, peak flow rates, and the associated concentrations of pollutants have all increased while the natural recharge of groundwater has decreased.

Study Area 3 is part of the combined sewer service area in the City, which was identified as Study Area 1 in the Wet Weather Flow Master Plan (WWFMP). The main objective of CSO control for this area is to separate stormwater from the combined sewer system. This will assist in eliminating basement flooding as well as the overflow of combined sewage into Black Creek Drive. The following four CSO locations are located in the Study Area:

• Keele Street/Eglinton Avenue West • Kane Avenue/Dunraven Drive • Keele Street/Hillary Avenue • Hyde Tank Outlet

As part of the Class EA Study, the combined sewers within Study Area 3 will be analyzed and local knowledge collected to assess the prime origins of the CSO problem and recommend control options to improve receiving water quality. The following water quality objectives are specified:

• Achieve the MOE Procedure F-5-5 for a 90% wet weather CSO volume interception and treatment within the seven month period of concern from April 1 to October 31

• Improve receiving water quality

2.2 Objectives The Class EA has the following objectives:

• Assess existing major and minor stormwater as well as the combined/sanitary sewerage system

• Identify causes of chronic and/or historical basement flooding

• Develop improvement measures that meet the new level of service criteria established by the City’s 2006 Work Plan

• Improve water quality of the receiving water

2.3 Methodology The problem statement for the Area 3 Chronic Basement Flooding Class EA was developed based on a review of the existing conditions. Study Area 3 is subjected to basement flooding and CSO during large rain fall events. Based on recorded flooding experiences, a number of house and property clusters have been documented with recurring and chronic basement flooding. Suitable solutions to alleviate basement flooding and CSO at these clusters will be evaluated during this EA study.


1BPROBLEM STATEMENT


The proposed study will:

• Identify and evaluate the Area 3 Flooding Sub-Areas and CSO locations using the InfoWorks CS model

• Define and evaluate a variety of solutions including At Source, Conveyance, End of Pipe, and other solutions

• Evaluate the potential solutions for each of the identified flooding clusters

• Recommend preferred solutions for the flooding clusters and present them to public and agencies for review

• Document findings and submit them in a Environmental Study Report as per Schedule C of the MEA process

3. Existing Conditions

3.1 Socio Economic Environment 3.1.1 Land Use Study Area 3 is located within Wards 12, 15, and 17. Land use within the Study Area is composed of residential, employment areas, and green spaces according to maps in the City’s Official Plan, August 2007. Official Plan schedules and maps were briefly reviewed to understand associated issues for the Study Area.

Based on review of Official Plan Map 2 depicting Urban Structure, the area along Black Creek Drive is designated as a Green Space System. In Map 4 depicting Higher Order Transit Corridors, two GO Rail lines and two GO/TTC interchanges are also noted in the study area. The City Parkland Map 8A also designates several parks in the Study Area. The Rockcliffe Park on Black Creek Drive is noted as a Special Policy Area in Map 10. However, only northern parts of the park appear to be within the Study Area. Map 12 depicting Environmentally Significant Areas did not indicate any for this study area.

The land use map in the Official Plan shows largely residential land use with few employment area designations along Weston Road and northern parts of the Study Area. Mixed land use is noted along Eglinton Avenue West, Rogers Road, and Dufferin Street. Open space land use is noted throughout the Study Area including a large cemetery in the central part of the Study Area.

The Study Area is predominately residential (65%), with the remaining area composed of industrial, commercial, institutional, open, and undefined space. A detailed breakdown of land use classification is summarized in Table 3-1 and illustrated in Figure 3-1.

TABLE 3-1 Land Use Classification

Classification Area (ha) Percentage (%)

Residential Single Family 237.11 59

Residential Multilevel 23.13 6

Commercial 20.72 5

Institutional 34.5 8

Industrial 29.09 7

Open Space 4.4 1

Undefined 55.79 14

Total 404.74 100


2BEXISTING CONDITIONS

3.1.2 Archaeological Assessment Three former historic homesteads were once located in the study area and a historic watercourse once bisected this area. One of these former historic homestead sites falls within the boundaries of the Nairn Park, while the watercourse runs just below it. Therefore, early pioneer and native remains in this area may be potentially impacted.

A historic watercourse in Fairbanks Memorial Park bisects this area and native remains may be potentially impacted.

A copy of the Archaeological Stage 1 Investigations Report is provided in Appendix B.

3.2 Natural Environment The study area is located along Eglinton Avenue West between Black Creek Drive and just east of Dufferin Street. Black Creek Drive flows in a southerly direction along the western study boundary. The riparian green space along the Black Creek Drive corridor and the Canadian National Railway (CNR) rail lines are part of the City’s Natural Heritage System. Due to the heavily urbanized setting of the study area, natural heritage features are limited to urban to semi-urbanized parks and the Black Creek Drive riparian corridor.

The following available background information, studies, and databases were reviewed for the study area:

• Physiography of Southern Ontario, Chapman and Putnam, 1984 • Available Orthophotography • City of Toronto Official Plan • The Natural Heritage Information Database • Canadian Species at Risk Database • The Humber River Fisheries Management Plan (Ontario Ministry of Natural Resources

[MNR] and Toronto Regional Conservation Authority [TRCA] 2005)

A background review of the existing natural environmental conditions within the study area is summarized in the following paragraph. A more detailed Phase 1 Natural Environmental Report is provided in Appendix C.

A preliminary review of natural heritage information was completed for Study Area 3 with the objective of delineating natural heritage constraints for proposed measures currently being developed for control of basement flooding within the defined study area. The databases from the Natural Heritage Information Centre, Environment Canada Species at Risk, Canadian Wildlife Service Map Tool, and the Official Plans for the City were reviewed for the presence of significant natural areas within the study area limits. There are no Provincially Significant Wetlands, Areas of Natural and Scientific Interest, Life Science Sites, or Environmentally Sensitive Areas identified within the study areas.

Based on the Phase 1 review, the following natural heritage constraints have been identified for further consideration for Phase 2:

• A number of parklands/parkettes are present within the study area. Many of these parklands are isolated, whereas others are larger and associated with the riparian areas of Black Creek Drive. Many of these parklands contain treed areas and manicured portions

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containing recreational facilities (baseball diamonds). A large cemetery is present along the central portion of the study area. Table 3-2 summarizes the study area parks

• Potential for butternut trees may be found in semi-natural settings. This would likely include larger parklands such as Coronation Park, Tretheway Park, Keelesdale Park, and the Ravine lands between Paulson Road and Greenbrook Drive

• Older neighbourhoods within the study area contain mature tree specimens, which form part of the City’s “Urban Forest” community

• The outfalls with the study area are located within the concrete channelized section of Black Creek Drive. TRCA was consulted during an October 6, 2009 meeting and stated that there would not be any special requirements for a new outfall in the section as the new outfall would not impact the existing channel banks. However, any connection to the concrete section of Black Creek Drive should be investigated to ensure that the new connection does not undermine the channel concrete liner. Meetings of this meeting are included in Appendix F with the Public Consultation information.

TABLE 3-2 Summary of Parks and Green Spaces Based on Air Photos

Park Location

Coronation Park North of Eglinton Avenue West and east of Black Creek Drive

Tretheway Park North of Tretheway Drive and east of Black Creek Drive

Keelesdale park South of Eglinton Avenue West and east of Black Creek Drive

Ravine between Paulson Road and Greenbrook Drive

North of Paulson Road and South of Greenbrook Drive

Gulliver Park South of Gulliver Road and west of Keele Street

Green Hills Park South of Paulson Road and west of Keele Street

Woodrough Park North of Castlefield Avenue and east of Kincourt Street

Kay Garner Beltline Park Along CNR rail north of Eglinton Avenue West

Eglinton Gilbert Park South West Corner of Eglinton Avenue West and Gilbert Avenue (west of Caledonia Road

Haverson Park East of Haverson Boulevard and Woodenhill Court

Bert Robinson Park East of Caledonia Road, south of Kitchener Avenue

Prospect Cemetery South of Eglinton Avenue West between McRoberts Avenue and Harvie Avenue

Nairn Park West of Nairn Avenue North and south of Chudleigh Road

Fairbank Memorial Park East of Dufferin Street and south of Keywest Avenue

Walter Saunders Memorial Park East of Dufferin Street and north of Hopewell Avenue

Based on this preliminary information, the following areas may be provided opportunities for further consideration into the basement flooding study:



• Opportunities for placement of flood control structures may be present along right-of-ways or streets where there are no or few trees, or if the tree cover is younger and can be replaced, subject to approval by Toronto Urban Forestry

• Opportunities for placement of flood control structures may also be present in parklands and sports fields containing manicured areas subject to approval by Toronto Parks Department

Some locations in Study Area 3 may fall under TRCA regulations (Ontario Regulation 166/06), which typically apply to stream valley corridors, wetlands, and hazard lands.

3.3 Technical Environment/Information 3.3.1 Sewer System Sanitary and Combined Sewer System The Minor System in Study Area 3 is composed of combined, storm, and sanitary sewers elements. The sanitary and/or combined sewers flow generally in a westerly direction, through the Hillary Combined Sewer Trunk to the Rogers Road Trunk Sewer, and eventually discharge at the Humber Treatment Plant. The area, units, population, sewer segments, and total sewer length contributing to the sewer system as well as the Study Area 3 sewer system is summarized in Table 3-3. Figure 3-2 shows the combined and sanitary sewer system and minor system boundary for Study Area 3.

Storm Sewer System Five separate storm sewers drain in three directions within Study Area 3. Two storm sewers discharge to Black Creek Drive, one storm sewer outlets into the Cedarvale Ravine, and two storm sewers continue south to the City’s former City of Toronto system south of Rogers Road. The storm sewers contributing to the Sewer System within Study Area 3 are summarized in Table 3-3. Figure 3-3 illustrates the storm sewer system and minor system boundary for Study Area 3.

TABLE 3-3 Summaries of System Data

Area Area (ha)

Units (Lots) Pop

Combined/Sanitary Sewer Storm Sewer

Combined/ Sanitary Sewer

Segments Length

(m)

Storm Sewer

Segments Length

(m)

Area 3 – Minor System 543.34 8,704 33,822 1,275 77,204 322 16,624.8

Minor System 898.89 14,275 61,171 2,092 131,065.8 665 38,079.8

ha – hectares m – metre



FIGURE 3-1 Land Use Classification

Figure located in folder on CD provided named EA_Report_Figures



FIGURE 3-2 Area 3 Combined and Sanitary Sewer System




FIGURE 3-3 Area 3 Storm Sewer System Figure located in folder on CD provided named EA_Report_Figures



3.3.2 Major System The Major System contributing to Study Area 3 extends beyond the boundary to the north and east. Within Study Area 3 the Major System flows in two directions and geographically the boundary is defined by Vaughan Road as the dividing point for the overland flow to the east and west. Using Vaughan Road as the marker, this dividing line can be projected up to the northern boundary of Study Area 3. Numerous gullies or low spots within Area 3 do not have a direct outlet and a significant amount of ponding occurs—a primary issue of the Major System. The area around Harvie Avenue and Cudleigh Road is one of these areas in which significant ponding occur before flow reaches an elevation such that the flow can continue along the existing major system.

The Major System network was defined using the conditioned digital elevation models (DEM) and specialized micro drainage tools to define surface flow paths along road networks, engineered and natural open channels, and backyards. Figure 3-4 illustrates the results of the Major System boundary and the flow path analysis in the study area. A detailed explanation of the technique used to generate the flow direction for the Major System is included in the Modelling Technical Memorandum located in Appendix D.

3.3.3 Historical Development of the Area A combined sewer drainage system was originally constructed in the Study Area that carried both sanitary and storm drainage. The Study Area is located in what was formerly known as the Borough or Township of York. The first development was constructed in the 1920s and 1930s, with the largest period of growth occurring between the 1950s to 1970s.

The City’s current sewer design standards are much higher than standards used during the original construction of the sewer system. Design criteria standards increased in the 1960s but are not the same as today’s standard. The combined sewer system was not designed to convey the fully developed area and increased paved areas. In the late 1960s, partial storm sewer separation to convey road drainage was constructed within some areas of the Borough of York. In 1990, sanitary storage facilities to relieve basement flooding were constructed throughout the Study Area. However, these storage tanks were not designed to accommodate flow from storm events greater than a 1:2 year storm event.

3.3.4 Previous Studies and Improvement The oldest combined trunk sewers in Area 3 are along Rogers Road and Chudleigh Road and then join up with the Hillary Trunk that runs along Hillary Avenue. In the 1950’s as the area development a trunk sewer was built along Eglinton Avenue West and Keele Street and relief trunk sewers parallel to the existing Roger and Chudleigh trunks were also built. In the 1960’s the first studies and improvements were carried out in Study Area 3 to address the chronic basement flooding.

In 1968 and 1968, Gore and Storrie conducted studies for the City of York that developed a sewer separation program and it was planned to convert one of the existing combined trunk sewers on Rogers Road or Chudleigh Road to a storm sewer after the separation program was completed. The sewer was never converted to a storm sewer and continues to operate as a combined sewer.



In 1976, Paul Theil Associates introduced the idea of using inlet control measures. The inlet control measures were to prevent excessive amount of storm water from entering the sewer in order to reduce surcharge. The resulting excess surface runoff was to be contained in underground storage structures. The runoff from grass and paved areas was to be diverted to the underground storage and then released back into the existing sewer system at a rate that would not cause basement flooding. The storage structures were sized based on runoff from a 10 year design storm. In total 63 underground storage facilities were built as part of the Paul Theil project. This program reduced the number of chronic basements that flooded however there were a couple of concentrated areas that still experience flooding. The area of Harvey and Nairn Avenue have experience the most severe and highest frequency of basement flooding even with the various improvements to the area.

3.3.5 Sewer Use By-Law at the time of Construction A combined drainage system was constructed in the majority of the Study Area with the sanitary and storm laterals directly connected to the combined sewer system. A separate drainage system was constructed for areas that developed from 1960 to 1970. The house sanitary laterals were connected to the sanitary sewers and the storm laterals were connected to the storm sewers. For homes constructed after 1965 the foundation drains were connected to the storm sewer system. Homes prior to 1965 had their foundation drains connected to either the sanitary or combined sewer system. In the combined sewer area the downspouts are generally connected to the combined sewer and in separated areas the downspouts are generally connected to the storm sewer.



FIGURE 3-4 Major System Overland Flow Path




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3.3.6 Historical Basement Flooding Study Area 3 locations with historical and/or chronic basement flooding were identified based on a number of sources, the primary source being the City’s Flooding Report completed for the May 12, 2000 flood. The report contains an extensive review of the flooding and compiled details of houses and properties that experienced flooding problems. This information was supplemented by review of flooding information from the August 19, 2005 and the July 9, 2008 storm events. A special note was made of the locations with repeatedly reported flooding. Information was also obtained from residents during town hall meetings held by City officials and from Councillors. The report did not consider flooding in the northern industrial area since there are no basements at this location. Table 3-4 summarizes the findings of all the sources for historical and/or chronic basement flooding in Study Area 3. Figure 3-5 illustrates the historical basement flooding reported for the June 23, 2008, August 19, 2005, and May 12, 2000 storm events.

The reports of flooding generally occur in confined areas or clusters. Based on review of information on the flooding locations and hydraulic modelling for the existing system condition, 17 cluster areas were identified where chronic and historical basement flooding had previously occurred or could potentially occur. Figure 3-6 shows the 17 cluster problem areas that have experienced historical and/or chronic basement flooding. The 17 problem cluster areas were then further refined to eight (8) Sub-Areas based on the development and evaluation of alternative solutions. This process is further defined in Section 6 of this report.

TABLE 3-4 Summary of Historical and/or Chronic Basement Flooding in Study Area 3

Location Reasons for Inclusion in Basement Flooding Investigation

Lonborough Avenue and Richardson Avenue Identified in the May 12, 2000 flooding report

Cameron Avenue and Scott Road There were nine houses with reported flooding in the May 12, 2000 storm and one in the August 19, 2005 storm

Snider Avenue, Montcalm Avenue, and Bowie Avenue

There were two houses with reported flooding in the May 12, 2000 storm and five in the August 19, 2005 storm

Chamberlain Avenue and Schell Avenue Identified in the May 12, 2000 flooding report

Ennerdale Road south of Eglinton Avenue A few residents reported basement flooding to City officials after the July 8, 2008 storm

Northcliff Boulevard Identified in the May 12, 2000 flooding report Repeat flooding in July 9, 2008 storm

Harvie Avenue, Nairn Avenue, and Chudleigh Road

Identified in the May 12, 2000 flooding report Repeat flooding in July 9, 2008 storm

Miranda Avenue and Bowie Avenue Identified in the May 12, 2000 flooding report

Harvie Avenue and Thornton Avenue Identified in the May 12, 2000 flooding report

Vaughan Road and Glenholme Avenue Identified in the May 12, 2000 flooding report

Silverthorne Avenue and Commodore Avenue Identified in the May 12, 2000 flooding report

Lavender Road and Kane Avenue Identified in the May 12, 2000 flooding report

Rosethorn Avenue and Rogers Road Identified in the May 12, 2000 flooding report



TABLE 3-4 Summary of Historical and/or Chronic Basement Flooding in Study Area 3

Location Reasons for Inclusion in Basement Flooding Investigation

Gilbert Avenue and Rogers Road Identified in the May 12, 2000 flooding report

Dynefore Road Residents reported basement flooding to City Officals, chronic flooding

Earlscourt Avenue Identified in the May 12, 2000 flooding report

Area defined by Keele Street and Caledonia Road between Kitchener Avenue and Hilary/Aileen Avenues

One house identified during a town hall meeting with reported flooding; cluster area defined is based on low lying area or sag

Area defined by Westmount Avenue and Oakwood Avenue between Jesmond Avenue and Rogers Road

One house identified during a town hall meeting with reported flooding; cluster area defined is based on low lying area or sag

3.3.7 Rainfall Data Ten rain gauges and six flow gauges to measure precipitation and collect flow data in 2007 and 2008 were provided by the City. As shown in Table 3-5, three rainfall events (July 08, 2008, July 19, 2008, and November 14, 2008) and five flow gauges were used to calibrate and validate the InfoWorks model.

Data from the 10 surrounding rain gauges located in the vicinity of the Study Area were used to apply the Distributed Rainfall Modelling Technique (DRMT) and create rainfall surfaces for each modelling time step at the centroid of each catchment’s tributary area. This approach helped to account for the spatial variability of storm events over a relatively large drainage area. A detailed explanation of the rainfall analysis is summarized in the Modelling Technical Memorandum, located in Appendix D. Figure 3-7 shows the approximate installation location of the rain gauges.

Rain Gauge: Castlefield (Station ID: 26) Flow Gauge Data Available for Events?

Event Date Depth (mm) Y-08 Y-09 Y-11 Y-12 Y-13

July 08,2008 36 Yes Yes Yes Yes Yes

July 19,2008 37 Yes Yes Yes Yes Yes

Nov 14,2008 22 Yes Yes Yes Yes Yes

mm – millimetres

3.3.8 Flow Monitoring Data Five flow monitoring gauges were used in the wet weather flow analysis. A detailed explanation of the flow monitoring analysis is summarized in the Modelling Technical Memorandum, Section 3, located in Appendix D. Figure 3-7 shows the approximate installation location of the flow monitors.



As shown in Table 3-5, three rainfall events were used in the flow monitoring analysis. Average dry weather flow (DWF) for these events are presented in Table 3-6.

TABLE 3-5 Average Dry Weather Flow

Flow Gauge

Area (ha) Population System

Type July 08, 2008 July 19, 2008 November 14, 2008

DWF(Lpcd) DWF(Lpcd) DWF(Lpcd)

Y08 32 1,560 Combined 0 0 0

Y09 117 8,802 87 127 198

Y11 101 4,347 Combined 1424 1728 556

Y12 35 2,435 Storm Storm Station, No DWF

Y13 508 29,874 Combined 159 98 88

Lpcd – litres per capita per day



FIGURE 3-5 Historical Basement Flooding Reported




FIGURE 3-6 Cluster Areas Based on Historical and/or Chronic Basement Flooding




FIGURE 3-7 Rain Gauge and Flow Monitoring Location




3.3.9 Field Data and Information The field survey of the Study Area was completed in fall of 2009. The objective of the survey was to visually inspect each property from the street to determine if the downspouts discharge to the surface or underground. The survey also identified properties with reverse slope driveways and the location and type of catchbasins. During the survey, the overland flow path for the areas was observed and any opportunities or concerns noted.

The field survey was conducted for 14,559 properties. Downspouts were investigated to determine their level of connection and disconnection. Based on the number of downspouts per building and the number connected and disconnected, the data was analysed and separated into the following four categories:

• 100% Connected – all downspouts on a building were connected • 66% Connected – two out of three downspouts on a building were connected • 33% Connected – one out of three downspouts on a building were connected • 50% Connected – one out of two downspouts on a building were connected

Figure 3-8 summarizes field survey results focusing on the level of the connectivity and location of the type of downspout disconnection. The City’s mandatory downspout disconnection by-law comes into effect for combined sewers in 2011 and for sanitary and storm sewers in 2013. The goal is to achieve 75% downspout disconnection. Approximately 60% of the homes in Study Area 3 have some level of downspout disconnection.

The field survey identified 1298 properties with reverse slope driveways. Figure 3-9 illustrates the location of properties with reverse slope driveways.

The catchbasins survey identified nine types of catchbasins. The field survey identified 16 different types of catchbasins in Study Area 3. Figure 3-10 summarizes the results of the catchbasin inventory.

The Field Guide that was used for the field survey investigation describes the type of catchbasin in Study Area 3 and is included in Appendix D.

3.3.10 Desktop Geological Assessment General geotechnical information was available for Study Area 3; however, detailed information from previous projects and/or boreholes was not available. Hydrogeological information was not available for the Study Area. A hydrogeological investigation may be needed in the detailed design phase.

The bedrock in the vicinity of Study Area 3 is the Georgian Bay formation that consists predominantly of weak to medium strong shale with interbeds of strong to very strong limestone and siltstone. With the exception of the City’s downtown area, the surface of the bedrock lies at depths generally exceeding 20 m to 40 m. The undulating surface of the rock has a regional dip to the southeast of about 5 m per kilometre (km). There are at least two deep buried valleys in the bedrock, one underlying the Don River and the other at the west end underlying the Humber River.

The sequence of the overburden soils overlying the bedrock is complex and reflects the complex geological history of the area. The region has experienced as least two, but possibly as many as four glaciations interrupted by warmer climate inter-glacial periods. The impacts of this



complex geology on civil engineering projects includes the expectation of encountering variable soil conditions even within short distances, the predominance of coarse and fine grained cohesion less deposits, the occurrence of boulder, the presence of buried valleys, and a generally high groundwater table.

The overburdened soils expected within the Study Area can be grouped into five major soil groups: fill, glacial tills, fine-grained non-plastic soils, fine-grained plastic soils, and coarse-grained granular soils. Bedrock in this area on the alignment of Eglinton Avenue West between Keele Street and Richardson Avenue lies at depths between 25 m and 35 m. Bedrock lies deeper than 35 m elsewhere in the Study Area.

A copy of the desktop geotechnical review completed by Coffey Geotechnics is included as Appendix E.



FIGURE 3-8 Field Survey Results – Downspout Connectivity




FIGURE 3-9 Field Survey Results – Reverse Driveways





FIGURE 3-10 Field Survey Results – Catchbasin Type


4. Model Development

4.1 Existing Data Data used to develop the hydrologic-hydraulic model for Study Area 3 included sewer network data; meteo-hydrologic data; topographical data; aerial photos; land use, parcel and building maps; water consumption; groundwater conditions; and soil conditions. Information was also derived from basement flooding reports and discussions with former employees of the former City of York Public Works Department. Field visits and discussions with residents were documented.

The sewer model was developed using sewer network data including the combined, storm, and sanitary sewer dimensions and inverts and their connection and material. This data was derived from the City’s Geographic Information System (GIS) database of sewer networks in the former City of York. Data check and data verification activities were conducted to ensure that data properly described the sewer system in Study Area 3.

The metro-hydrologic data includes rainfall, evaporation, and flow data. Since evaporation is less during a rainfall event, it was assumed to be insignificant. Ten rain gauges and six flow gauges and precipitation and flow data in 2007 and 2008 were provided by the City. Original data sources were processed extensively to develop the micro drainage input data required by the InfoWorks CS model. Typical data processing tasks included Digital Elevation Model (DEM) re-conditioning, flow path analysis, surface drainage network definition, inlet capture curve calculation, imperviousness calculation, and directly connected roof area estimation.

4.2 InfoWorks Model InfoWorks CS computer simulation models were developed to model the Study Area. InfoWorks CS integrates hydrologic and hydraulic functions into one interface. Hydrological parameters including precipitation and surface area data were used to generate runoff. Hydraulic parameters were used to simulate the open and close (sewer) channels that convey the flow generated over the tributary areas. The approach produced a model with small and logical major system segments and pipe-by-pipe minor systems. The developed model comprises of various components: catchments, combined, sanitary and storm sewer networks, overland channels, and hydraulic structures.

4.2.1 Model Set Up Three types of tributary areas were implemented in the model:

• Dry Weather Flow – a 450 L per capita per day (Lpcd) constant flow was used in this study. DWF was generated from the City’s 2001 population layer.

• Direct Connected Roofs – each of the catchment areas had a defined direct connected roofs area. Runoff from all storm events from directly connected roofs entered the Minor System at the nearest upstream node


3BMODEL DEVELOPMENT


• Other Areas Including Indirect Connected Roofs – flow generated at other areas was captured at a Major System node through partial or complete capture at inlet nodes and flow routing

Major System tributary drainage areas were delineated using block-by-block discretization. This approach was used because of difficulties that were encountered related to delineating small catchments using contour lines. The DEM obtained from the City was used to define hydrologic and surface hydraulic parameters. The original DEM was conditioned to improve the hydrologic and hydraulic functionality. The conditioned DEM was used to define flow paths and Major System links that, together with supplemental field and file data, characterize the surface drainage system.

4.2.2 Model Calibration A flow data monitoring program was not conducted as part of this Study Area as flow monitoring data was already available from the City. The flow monitoring locations were previously selected by the City of Toronto. Three rainfall events (July 08, 2008, July 19, 2008, and November 14, 2008) and five flow gauges were used to calibrate and validate the model.

Data from 10 surrounding rain gauges in the vicinity of the study area were used to apply DRMT and create rainfall surfaces for each modelling time step at the centroid of each catchment’s tributary area. This approach helped to account for the spatial variability of storm events over a relatively large drainage area.

The existing Study Area 3 InfoWorks model was developed and calibrated using three calibration parameters: Runoff Routing Value, Fixed Runoff Coefficient, and Initial Loss Value.

Seven surface types were considered during development of the model. The parameters and estimated runoff coefficient for the Study Area in the existing model are summarized in Table 4-1.

The existing Study Area 3 InfoWorks model was developed and calibrated using the processed rainfall and flow data.

3BMODEL DEVELOPMENT

TABLE 4-1 InfoWorks CS Model Calibration Parameters

Surface

Runoff Routing Value Surface Type

Initial Loss Value (m)

Routing Model

Fixed Runoff Coefficient

Horton Initial (mm/hr)

Horton Limiting (mm/hr)

Horton Decay (1/hour)

Directly Connected Roof Area 0.013 Impervious 0.0008 SWMM 0.9 Not Applicable Not Applicable Not Applicable

Non-directly Connected Roof Area for Storm Sewer

0.013 Impervious 0.0008 SWMM 0.9 Not Applicable Not Applicable Not Applicable

Road, Parking, and Driveway Area for Storm Sewer


Pervious Area Soil Type A for Storm Sewer

0.25 Pervious 0.0065 SWMM Not Applicable 250 25.4 2

Non-directly Connected Roof Area for Combined Sewer


Road, Parking and Drive way Area for Combined Sewer


Pervious Area Soil Type A for Combined Sewer



3BMODEL DEVELOPMENT

Appendix 3.3 of the Modelling Technical Memorandum located in Appendix D illustrates the measured and modelled hydrographs during the selected calibration events based on the existing model calibration parameters. The model yields higher combined sewer peak flows compared to the measured values even after the impervious area runoff coefficient is reduced to a significantly low value of 0.3.

Improved Model Calibration – Estimated Runoff Coefficient Because of the relatively low runoff coefficient values obtained using the historical flow values, a second approach was considered for calibrating the model. The approach compares the hydraulic grade line measured in the Hillary Trunk Sewer during a two-year storm event that was previously evaluated by the City. The revised calibration parameters and estimated runoff coefficient value for the Study Area in the existing model are summarized in Table 4-2.


3BMODEL DEVELOPMENT

TABLE 4-2 InfoWorks CS Model Calibration Parameters with Estimated Runoff Coefficient Value

Description Runoff

Routing Value

Surface Type Initial Loss

Value (m)

Routing Model

Fixed Runoff Coefficient

Horton Initial (mm/hr)

Horton Limiting (mm/hr)

Horton Decay (1/hour)

Directly Connected Roof Area 0.013 Impervious 0.0008 SWMM 0.85 Not Applicable Not Applicable Not Applicable

Non-directly Connected Roof Area for Storm Sewer


Road, Parking, and Driveway Area for Storm Sewer


Perviousness Area Soil Type A for Storm Sewer


Non-directly Connected Roof Area for Combined Sewer


Road, Parking, and Driveway Area for Combined Sewer


Perviousness Area Soil Type A for Combined Sewer



3BMODEL DEVELOPMENT

As noted in Table 4-2, the revised runoff coefficient for directly connected areas has been adjusted to 0.85 and 0.7 for impervious areas. The Hillary Trunk hydraulic grade line (HGL) during the 2-year design storm yields a similar profile as the City’s evaluation.

Appendix D includes the complete model development, analysis and results. Since model calibrated to the trunk sewer HGL provided more realistic (anticipated) runoff coefficients, this model has been carried forward for drawing systems analysis.


5. Assessment of Existing Systems

5.1 Flood Criteria A Flood Potential methodology was developed for evaluating the capacity of the Major and Minor Systems prior to flood damage and flood hazards occurring in the area. The Flood Potential was quantified based on surface depths and HGL elevation in the sewers. The Flood Potential quantifies the likeliness of flooding at specific locations in the Study Area based on whether or not a flood depth or HGL elevation trigger is reached. The model provides the best predictive tool based on assumed building elevations relative to sewer and street elevations. Potential flooding occurs when levels in surcharged sewers reach estimated basement elevations or ponding on the street reaches building elevations.

The potential for surface and/or basement flooding for this EA study was considered if:

• Surface water level is above the surface elevation (gutter elevation) by more than 300 mm

• Surcharge level in the combined and/or storm sewer is less than 1.8 m below the roof/ground surface elevation. The elevation of 1.8 m below ground is the approximate assumed basement elevations for homes with the basements directly connected to the combined or storm sewer

The potential flooding due to surface flow shows the water level in the overland flow system in the following three different categories:

• From gutter surface to 150 mm above surface, which indicates that the flow is contained within the curbs

• From 150 mm to 300 mm above gutter surface, which indicates the water is above the curb but contained within the street right-of-way, which indicates potential surface flooding for reverse slope driveway buildings

• More than 300 mm above gutter surface, which indicates potential surface flooding

The potential flooding due to an elevated HGL in the sewer system is also shown in the following three categories:

• The HGL elevation is below 1.8 m from surface (basement elevation) • The HGL is within the surface elevation and 1.8 m below surface • The HGL is above surface elevation, which indicates that the pipe is surcharged up to the

surface

Figure 5-1 illustrates the flood potential criteria assumed for Study Area 3.


4BASSESSMENT OF EXISTING SYSTEMS

FIGURE 5-1 Flood Criteria

Model results were compared with the Flood Potential evaluation and reported flooding locations to assess where critical flooding was most likely to occur within the Study Area. Results were used to develop remedial options and subsequent selection of the preferred alternative.

It is important to note that high flood potential from overloaded sewers or overloaded roadway drainage systems may or may not result in actual flooding. Actual flooding depends on the site-specific building and road construction standards that were in place at the time of construction and the particular design of each building. For example, the analysis would predict flooding if the HGL in the sewer rises above 1.8 m below the ground elevation regardless if a building or group of buildings has basements. Buildings without basements would not be flooded under this condition. Conversely, buildings with basement elevations below the 1.8 m elevation of the road will have a higher Flood Potential. Changes made to buildings after their initial construction may also affect actual flooding. Site-specific investigations would be required to assess building-specific Flood Potential.



5.2 Water Quality Criteria Targets for stormwater quality improvement were defined in the WWFMP to achieve “significant enhancement”. Stormwater quality objectives for the WWFMP included:

• Objective 7: Meet guidelines for water and sediment quality. − Indicators for Objective 7 include temperature/dissolved oxygen; nutrients, unionized

ammonia, chlorides and total suspended sediments; E. coli; inorganic compounds; organic compounds; and in-situ sediment.

• Objective 6: Virtually eliminate toxics through pollution prevention. − Indicators for Objective 6 include spills prevention/emergency response; contaminated

sites; discharges; and reduction in air emissions.

• Objective 9: Improve water quality in rivers and the lake for body contact recreation. − Indicators for Objective 9 include beach closures; and E. coli levels in non-beach areas.

• Objective 10: Improve aesthetics. − Indicators for Objective 10 include litter/garbage; animal wastes; and algae, turbidity,

odour, fish kills.

The InfoWorks model was used with the typical year rainfall as input to identify the existing system performance. These results were compared against the requirements of MOE Procedure F-5-5, which requires that 90 percent volumetric control of CSO is achieved at all control structures in the system for an average year from April to November. Table 5-1 presents the CSO and existing wet weather flow volumes for the four outfalls within Study Area 3. The four CSOs located within the Study Area are:

• Keele Street/Eglinton Avenue • Kane Avenue/Dunraven Drive • Keele Street/Hillary Avenue • Hyde Tank Outlet

This data was used as a baseline for the assessment of the solutions with respect to water quality. For the assessment of the CSO volume control, detailed flow conditions at each of the 4 CSO outfalls were analyzed. For the proposed solutions each of these CSO were required to meet the CSO level of control as identified in the MOE Procedure F-5-5 guideline. The locations of the four CSO locations are shown on Figure 5-2.

TABLE 5-1 Existing System Typical Year Performance

Percentage of WWF Volume Existing Condition Outfall

CSO Volume Existing Condition (m3)

Keele Street/Eglinton Avenue West 41,125 25%

Kane Avenue/Dunraven Drive 28,407 16%

Keele Street/Hillary Avenue 160,818 19%

Hyde Tank Outlet 80,031 36%



5.3 Assessment of Existing Systems 5.3.1 Simulation of Design Storm and Historic Events To estimate the level of protection in the existing drainage system, the dry weather flow, 2-year design storm, 5-year design storm, 100-year design storm, and May 12, 2000 historic storm were simulated and compared with the Flood Potential criteria. Results of the model simulation are shown in Figures 5-2 to 5-10 for the sewer systems and surface in the Study Area with respect to Flood Potential assessment.

Figure 5-2 illustrates the systems performance for dry weather flow conditions and shows that the exiting minor sewer system does not experience any potential flooding during DWF. Figure 5-3 to Figure 5-6 illustrates the Minor System performance for the 2-year, 5-year, 100-year design storms, and May 12, 2000 historic storm. The thin red lines show the locations with potential flooding that is a result of capacity constraints that result in the HGL rising to 1.8 m from the ground surface. The thick red lines show shallow pipes with HGL within 1.8 m from the ground surface.

Figure 5-7 to Figure 5-10 illustrates the overland or Major System flow for the 2-year, 5-year, 100-year design storms, and the May 12, 2000 historic storm. The red lines show potential surface flooding occurring when the depth of flow at the surface exceeds 300 mm. The red markers show potential surface flooding at locations where the surface flooding exceeds 150 mm near reverse slope driveway locations.

5.3.2 Potential Flooding Identification Results obtained from hydraulic models of the combined, sanitary, and storm systems were used in combination with information gathered from flooding reports, historical information, relevant information compiled during the EA study process, and comments received from stakeholders to identify and further define the cause of flooding in Study Area 3.

Figure 5-11 shows 3126 properties with potential flooding due to Minor System overload, while Figure 5-12 shows 537 properties with potential flooding due to overland or Major System ponding during the 100-year design storm. The number of properties with potential flooding is 3,287, with potential flooding of 376 properties possible due to overload of both the Minor and Major System. Based on this evaluation process, the primary causes of basement flooding in the Study Area were defined and problem areas within cluster areas defined. Initially there were 17 cluster areas identified within the Study Area. The 17 problem cluster areas were then further refined to eight (8) Sub-Areas based on the development and evaluation of alternative solutions. This process is further defined in Section 6 of this report.

The primary causes of basement flooding in the Study Area are summarized in the following five general categories:

• Combined sewer system surcharge • Storm sewer system surcharge • Surface flooding • Low lying areas • Reverse sloped driveways



Table 5-2 summarizes the causes of flooding for each Sub-Area based on these five general categories for the 100 year design storm.

TABLE 5-2 Summary of Causes of Basement Flooding by Sub-Area

Sub-Area Combined Sewer

System Surcharge Storm Sewer

System Surcharge Surface

Flooding Low Lying

Area Reverse Sloped

Driveways

1 2 3 4 5 6 7 8

Table 5-3 details the primary causes of basement flooding in Study Area 3 by street name for each Sub-Area for the 100 year design storm.

TABLE 5-3 Primary Causes of Basement Flooding in Each Sub-Area by Street Name (100 year design storm)

Sub-Area Street Name Cause of Flooding

1

Lonborough Avenue

Reverse slope driveways Low lying areas – localized sags in roadway Surface flooding 0 to 150 mm depth Combined sewer system surcharge

Beechborough Avenue Reverse slope driveway Surface flooding 0 to 150 mm depth Combined sewer system surcharge

Freeman Road Clearview Heights Trethway Drive Westacres Drive

Combined sewer system surcharge Surface flooding 0 to 150 mm depth Limited reverse slope driveways

Castlefield Avenue Kincor Street Woodborough Avenue Northwestern Avenue

Combined sewer system surcharge Industrial Area – no basements Low lying areas with no outlet Surface flooding 0 to150 mm depth

Bicknell Avenue Hertford Avenue Avon Drive

Combined sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth





2 Silverthorne Avenue Dunraven Drive


Commodore Avenue

Combined sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth Low lying area

Kane Avenue at Aileen Avenue and Kersdale Avenue


3 Hilary Avenue Old Weston Road

Combined and storm sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth Low lying area

Rowntree Avenue Chambers Avenue Rosethorn Avenue Silverthorn Avenue Blackthorn Avenue

Combined and storm sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth Low lying area

McRoberts Avenue

Combined sewer system surcharge on Kitchener Avenue Reverse slope driveway Surface flooding 0 to >150 mm depth Low lying area

4 Keith Avenue Gilbert Avenue Bowie Avenue Snider Avenue Montcalm Avenue Little Boulevard Chamberlain Avenue Miranda Avenue Hartley Avenue Fairbanks Avenue


5 Hunter Avenue Dynevor Road Kirknewton Road Ennerdale Road

Combined and storm sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth

Branstone Road Nairn Avenue Harvie Avenue

Combined and storm sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth





6 Vaughan Road Onslow Crescent Bansley Avenue Eleanor Avenue Glenholme Avenue Dufferin Street

Combined sewer system surcharge

Northcliffe Boulevard Allenvale Avenue


Keywest Avenue Gibson Street Amherst Avenue

Reverse slope driveway – limited Surface flooding 0 to 150 mm depth

7 Chudleigh Road Holmesdale Road

Combined sewer system surcharge Reverse slope driveway Surface flooding 0 to >150 mm depth Low lying area – no overland flow path

Nairn Avenue Harvie Avenue


Ennerdale Road Holmesdale Crescent Preston Road Hatherley Road

Combined sewer system surcharge Reverse slope driveway Surface flooding 0 to 150 mm depth

Rochdale Avenue Reverse slope driveway Surface flooding 0 to 150 mm depth

8 Westmount Avenue Northcliffe Boulevard


Genesse Avenue Martin Street Earlscourt Avenue Nairn Avenue

Combined sewer system surcharge Surface flooding 0 to 150 mm depth

Eversfield Road Combined sewer system surcharge Reverse slope driveway Surface flooding 0 to 150 mm depth

Rockvale Avenue Blandford Street Oakwood Avenue

Reverse slope driveway Surface flooding 0 to >150 mm depth

Lauder Avenue Reverse slope driveway Surface flooding 0 to 150 mm depth



FIGURE 5-2 CSO Locations




FIGURE 5-3 Existing Condition Sewer System – Dry Weather Flow




FIGURE 5-4 Existing Condition Minor Sewer System – 2-Year Design Storm




FIGURE 5-7 Existing Condition Minor Sewer System – May 12, 2000 Historical Storm




FIGURE 5-8 Existing Condition Major System – 2-Year Design Storm




FIGURE 5-11 Existing Condition Major System – May 12, 2000 Historical Storm




FIGURE 5-12 Existing Condition Minor Sewer System Flooding Potential for 100-Year Design Storm





FIGURE 5-13 Existing Condition Major System Flooding Potential for 100-Year Design Storm


6. Solution Development

6.1 Solution Development The Study in Area 3 is different from the other basement flooding studies being conducted by the City of Toronto as the study also addresses water quality issues through CSO controls. The solution development for other basement flooding studies was to identify cluster areas and then depending on the local specific conditions of each of the cluster areas, the alternatives addressing the problem were developed. For studies conducted under the Wet Weather Flow Master Plan the solutions to address the problem of wet weather flow were classified into three types of controls: Source Control, Conveyance Control and End-of-Pipe Control. The approach to alternative development to address basement flooding and water quality problems in Area 3 therefore looked at a cluster approach versus a holistic approach.

6.1.1 Cluster Approach The Cluster approach is an approach used in the other basement flooding studies with stormwater drainage issues. The study areas were delineated into cluster areas based on the historic basement flooding and existing drainage systems. Having identified the primary causes of basement flooding in each cluster, the remediation plan addressing the basement flooding was developed.

6.1.2 Holistic Approach The Holistic approach is a hybrid approach that considers

• The Hydraulic Gradeline (HGL) within the sewer system to ensure the depth is within acceptable levels below the ground surface, similar to the cluster approach,

• Water quality to water courses, similar to the approach used in the WWFMP to develop a remediation plan addressing water quality.

6.1.3 Approach Comparison Initial investigation, modelling and design was conducted using both the cluster and holistic approaches to better defined the constraints of each approach. Table 6-1 summarizes the comparison of the cluster and holistic approach based on the following criteria:

• Timeline for Implementation – the ability of the approach to be staged or phased to reduce the time for implementation of solutions within the study area

• Water Quality – the ability of the approach to meet the water quality objectives of the WWFMP for the treatment of stormwater

• Parks – the compatibility of the approach with the existing land and recreational use

• Cost/Benefit – the cost of the approach compared to the number of benefiting properties from basement flooding and or the benefit to the water quality


5BSOLUTION DEVELOPMENT

• WWFMP – the ability of the approach to meet the source control, conveyance and end of pipe control objectives including the MOE procedure F-5-5

• Social – the potential for the approach to impact social criteria such as aesthetics, land use compatibility, and archaeological

• Technical – the potential for the solutions within the approach to be constructed.

TABLE 6-1 Comparison of Cluster versus Holistic Approach

Criteria Cluster Approach Holistic Approach

Timeline for Implementation Yes – the cluster solutions could be staged for implementation

Yes – the holistic solutions could be staged for implementation

Water Quality No–water quality objectives for storm water were not assessed

Yes –water quality objectives for storm water were assessed

Parks No – the size of some of the cluster storage solution would not be compatible with existing parks

Yes – the holistic solution is compatible with existing parks

Cost/Benefit No – cluster solutions would not meet the cost/ benefit requirements established by the City, and water quality were not evaluated

Yes – the holistic solution is anticipate to meet the cost/benefit requirements and there is benefit for water quality

WWFMP No – meets source and conveyance controls but not F-5-5

Yes – meets source, conveyance and end of pipe controls as well as F-5-5

Social No – some of the cluster solutions would have social impacts

No – some of the holistic solutions would have social impacts

Technical Yes –cluster solutions could be implemented

Yes – holistic solutions could be implemented

Based on the comparison table it was determined to proceed with the holistic approach to solving the basement flooding and water quality within Study Area 3.

6.2 Source Controls 6.2.1 Downspout Disconnection Program Downspout disconnection or roof leader disconnection would reduce the storm flow entering the sewer system and is applied at the lot level subject to landowner implementation. The City of Toronto has implemented a roof leader disconnection by-law which states that all roof leaders are to be disconnected from the combined sewer system by 2011 and the remaining sewers by 2016.

The main advantages downspout disconnection is that it encourages storm water infiltration, reduces requirements for additional sewer system capacity and potential downstream impacts and could be implemented at a much lower cost than other alternatives. The main disadvantage, of this alternative is that it does not provide a complete solution of eliminating basement flooding to the required level of protection. The measures at lot level are subject to the homeowner’s initiative, and its success is subject to their implementation and maintenance by the homeowners.



The downspout disconnection program is an ongoing City initiative to reduce the direct stormwater flow contributions from roof areas to storm or combined sewers that lead to higher peak flows and increased surcharge in sewers. For the existing condition, approximately 60% of the properties have some level of downspout disconnection. For the proposed solution, it was assumed that 75% downspout disconnection was achievable. This accounts for properties where direct downspout disconnection would create a hazardous condition such as flooding of adjacent properties or contributing to slope failures or erosion in ravines; or where the disconnection is technically not feasible.

The size of each roof area within each catchment was calculated using GIS techniques. In the model, directly connected roof areas were connected to the nearest upstream storm or combined sewer maintenance hole representing direct connections to the sewer. Direct inflows into sewers were limited to the 5-year peak flow generated over the roof area. Unless the directly connected roof area in a catchment was already below 25% (or 75% disconnected), the disconnection analysis reduces the directly connected roof area down to 25% to represent 75% disconnection of downspouts in the system.

Modelling results that include downspout disconnection show a reduction in Flood Potential of properties from 3,126 to 2,468 based on the impact of the Minor System and an increased in Flood Potential of properties from 537 to 681 properties based on the impact of the downspout disconnection on the Major Systems (see Table 6-2). Comparison data is summarized in Appendix D that contains figures illustrating the 75% roof disconnection condition, the affect on the Minor and Major Systems, and Flood Potential of properties.

TABLE 6-2 Existing Condition and 75% Roof Disconnected Potential Flooding Properties

Minor System Potential Flooding Properties in 100-year Design Storm

Major System Potential Flooding Properties in 100-year Design Storm

Duplicate Properties in Major and Minor System Total

Existing Condition 3,126 537 376 3,287

75% of all Downspouts Disconnected 2,468 681 425 2,724

6.3 Conveyance Controls Conveyance controls can be defined as overt methods of storing, slowing and/or staggering the flow of stormwater during wet weather events. These controls do not reduce or remove the volume of water that enters the sewer system. Conveyance controls slow or stagger the rate of flow to avoid mixing between the combined and storm sewers, thereby reducing the frequency of CSO events. Conveyance controls can include flow balancing, sewer separation, in-line and off-line storage as well as pipe upgrades for conveyance.

Study Area 3 is comprised of numerous low lying areas. In Sub-Areas 1 and 7 these low lying areas have no outlet. Downspout disconnection and flow balancing were use to optimize the major and minor system, however these improvements alone do not provide a complete solution to the basement flooding in the area. The Sub-Areas were investigated individually to determine if there was a viable solution for each of the areas that were



independent of the other Sub-Areas. This investigation resulted with solutions that could prohibitive based on the cost to benefit ratios of the solution or the constructability of the solution. The Sub-Area solutions investigated also did not address the water quality issues related to the CSOs in the area. Based on this initial investigation and discussions with the City of Toronto, it was determined to take a more holistic approach to solving the basement flooding and water quality in Study Area 3.

Specific alternatives were considered that addressed water quality/water quantity in accordance with the WWFMP. A holistic approach was defined to include a combination of storage, storm trunk sewer and conveyance to store or convey the major system flow away from low lying areas. This approach included road/sewer separation that would intercept the road runoff and reduced the contribution of flow to the combined sewers which in turn reduced the combined sewer overflows within the study area.

6.3.1 Flow Balancing The logic of flow balancing is to maximize the existing minor and major system capacity and minimize the requirement for new infrastructure. Flow balancing reduces flow into the sewers and utilizes the major system capacity so that improvement works can be focused on the location where there is no major system outlet. Flow balancing is achieved by introducing inlet control devices (ICD), sealing inlets to overloaded storm or combined sewers, and by adding new inlets to reduce surface flooding in the Major System.

New ICD configurations assume orifice-type control at the intake to the connecting pipes from the catchbasin structures to the road sewer. Appendix F contains a more detailed discussion on the implementation of the ICD with respect to modelling. Figure 6-1 illustrates the locations for ICD and sealed catchbasins. In total, 526 ICD and 28 sealed catchbasin sites have been identified for further verification at the detailed design stage. Table 6-3 summarizes the number of ICD proposed for each Sub-Area as well as the number of sealed catchbasins. Figure 6-1 shows the approximate location of the proposed ICDs and sealed catchbasins for each Sub-Area.

By restricting the flow with the ICD, ponding and/or flow depth at or near catchbasins may increase during large storm events. The locations of ICD identified by this EA study have been evaluated using best available grading information taken from digital elevation models so that the maximum depth of flow or ponding would not exceed a 0.3 m maximum depth and/or 0.15 m in areas with reverse slope driveways. However, the impact should be reviewed during detailed design, when more detailed grading/topographic information is collected, so that local flooding does not occur around catchbasins from the ICD. CH2M HILL recommends that each location be designed based on selection of the appropriate type, size, and location of the ICD during detailed design.

Peak flow balancing incorporates new inlets at locations with high flood potential due to an overloaded Major System. This approach assumes that for each additional catchbasin installed, the inlet capacity will capture 100% surface water to reduce the flood potential to acceptable levels. Additional catchbasins will increase the flow in the sewers and reduce the surface runoff.



TABLE 6-3 Summary of Proposed Inlet Control Devices (ICDs) and Sealed Catch Basins based on the 1:100-Year Storm

Sub-Area Number of Inlet Control Devices

(based on 45 L/s) Number of Catchbasin to be

Sealed

1 110 3

2 11 1

3 84 5

4 147 2

5 56 0

6 26 3

7 32 1

8 60 13

Total 526 28

L/s – Litres per second



FIGURE 6-1 Location of ICD and Sealed Catchbasins




Locations where new inlets (intakes) are proposed are illustrated in Figure 6-2. The analysis assumes that 100% of surface water is captured at the specified location. However, the actual catchbasin configuration (for example, type, number, size, and grates) of the new inlets may be adjusted at the detailed design stage to meet current design and construction criteria and flood protection objectives. Based on an average inlet capacity of 45 L/s (0.045 m3/s) the approximate number of additional catchbasins or new inlets required has been summarized in Table 6-4 by their associated Sub – Area. This estimate of additional catchbasins or new inlets will be refined during detailed design and will take into consideration other factors such as natural depressions and sags into the calculations This establishes the number of equivalent catchbasins per Sub-Area. There are 132 locations in which new inlets are proposed or 963 new equivalent inlets based on a capture rate of 45 L/s.

Solutions were modelled sequentially; therefore, the modelling incorporated the downspout disconnections and ICD to determine new peak flows for the Minor and Major System.

TABLE 6-4 Summary of Proposed New Catchbasins and Peak flows based on 1:100-Year Storm

Sub- Area Number of Proposed New Catchbasin Locations

Number of Proposed New Equivalent Catchbasins based on an average inlet capacity (45 L/s)

1 20 185

2 31 142

3 12 139

4 29 202

5 12 65

6 7 83

7 9 66

8 12 81

Total Numbers 132 963

L/s – Litres per second



FIGURE 6-2 Location of Proposed Catchbasins – Inlet Capacity Based on Each Location




FIGURE 6-3 Location of proposed Storm Sewers, Sanitary Sewer and Storm Tunnel Figure located in folder on CD provided named EA_Report_Figures



6.3.2 Storm Water Conveyance System A storm water trunk sewer is proposed to convey the storm water from the study area to the existing outlet at Black Creek Drive. The trunk sewer is recommended to be constructed using tunnelling. If the ultimate goal is to have a separate sewer system, the stormwater trunk sewer will provide an opportunity for the achievement of this goal in Study Area 3. The two alignments for the storm water trunk sewer considered were a northern and a southern alignment. The northern alignment was proposed along Eglinton Avenue West that would correspond with the proposed subway along Eglinton Avenue. The southern alignment proposed was to follow the current alignment of the Hilary Trunk sewer. A desktop analysis of the two alignments was conducted and considered hydraulics and constructability of the two alignments. Table 6-5 summarizes the desktop analysis of the alignments. Based on the general hydraulics of the two alignments and the comparative cost, the alignment following the Hilary Trunk Sewer was recommended.

TABLE 6-5 Summary of Alignment Analysis

Eglinton Avenue West Alignment Hillary Trunk Alignment

Description North alignment following to an outlet at Black Creek Drive

Southern alignment following the Hilary Trunk sewer to the outlet at Black Creek Drive.

Outlet Black Creek Drive – existing storm sewer outlet could be utilized

Black Creek Drive – existing storm/combined sewer outlet could be utilized

Hydraulics The natural slope of the drainage area is from north to south, therefore deep collector storm sewers (up to 40m in depth) would be required to pick up the flow in low lying areas and convey to the trunk sewer.

The natural slope of the drainage area is from north to south, storm sewers would be required to pick up the flow in low lying areas and convey to the trunk sewer.

Constructability To follow the proposed Eglinton Avenue West subway line the trunk sewer would need to constructed under the subway and be at least 3 times the diameter of the trunk sewer deeper than the subway. The depth of the trunk sewer would start at 30 m below ground. Collector sewers would need to be significantly deeper than 30m to convey southern low lying areas to the trunk sewer Surcharge of the storm trunk sewer could pose a potential threat to the subway.

To follow the Hilary trunk alignment the trunk sewer would need to be constructed at least 3 times the diameter of the trunk sewer deeper than the existing trunk sewer.

Cost The trunk sewer and collector storm sewers would be deeper than the other alignment and therefore would be more expensive.

The trunk sewer and collector storm sewers would be shallower than the other alignment and therefore would be cheaper.

To convey flow from the Major System within the Study Area, a 3,000 mm diameter storm water trunk sewer 2,567 m in length is proposed from Fairbank Memorial Park to the outlet at Black Creek Drive. New collector storm sewers connected to the trunk sewer or existing storm trunk sewers are proposed to convey flow to the storm water trunk sewer and reduce localized surcharging and/or flooding. These additional storm sewers and storm trunk sewer are designed to meet the flooding criteria for the Major and Minor System within the



Sub-Areas and study area. The trunk sewer also further achieve sewer separation within Study Area 3.

The location of the proposed storm water trunk sewer and collector storm sewers is illustrated in Figure 6-3. Table 6-6 summarizes the sizes and lengths of the proposed new storm sewers for the entire Study Area. A more detailed summary of proposed collector storm sewer sizes and lengths by Sub-Area is provided in Figure 6-3.

TABLE 6-6 Proposed Collector Storm Sewer Summary for the Entire Study Area

Storm Sewer Pipe Diameter (mm) Total Length (m)

375 305

525 277

600 1,602

675 230

750 849

825 125

900 1,468

1,050 576

1,200 1,064

1,350 1,574

1,500 222

1,650

774

6.4 End of Pipe Control End of Pipe Controls as the name suggest are implemented at the outlet of the system, however this control includes underground storage tanks for either storm or combined sewage which typically are located within the system based on the hydraulic constraints of the system.

6.4.1 CSO Tanks CSO tanks were required in two of the sub-areas to address localized surcharge in the combined sewer system. This surcharge could not be controlled through the implementation of downspout disconnection, flow balancing or road sewer separation. The hydraulics of the combined sewer system dictated the location for the CSO tanks within Sub-Areas 6 and 7 and available space for the tanks was investigated in these areas. There are a number of small parkettes in Sub-Area 6 and 7; however, due to the volume requirements of the proposed CSO tanks Nairn Park and Fairbanks Memorial Park were selected as the proposed CSO tank location.

Underground CSO tanks in the Fairbank Memorial and Nairn parks are part of the recommended solution. CSO tanks in Fairbank Memorial Park and Nairn Park analysis and concept drawings are illustrated in Appendix 5.2 in Appendix F. The InfoWorks CS model



incorporates both CSO tanks to provide protection against combined sewer overload along the Hillary Trunk and downstream, prior to the construction of the storm water trunk sewer as the chronic flooding experienced at Harvey and Nairn is very sensitive to the level of the Hydraulic Gradeline within the Hillary Trunk.

6.4.2 Additional Storage Storm Water Solution for Rowntree Avenue Modelling results show potential flooding at the intersection of Rowntree Avenue and Old Weston Road. A 3,600 m3 storage volume has been identified to maintain existing 100-year storm event peak outflow to storm sewer system. Storage could be provided either through in-line or sub-surface storage. This volume was determined based on an allowable flow in the first storm sewer segment downstream of Study Area limits. Refer to additional details of this analysis are included in Appendix 5.3 of Appendix D.

Sanitary Sewer in Hillary Avenue Modelling results show that under 100-year design storm conditions, the Hilary Trunk Sewer (1,800 mm diameter) would result in a freeboard of 1.15 m at maintenance hole MH360-022 and would affect approximately 15 houses. One alternative solution would be to provide small local sanitary sewers on each side of the road to connect these homes to a downstream location in the trunk. This new local sanitary sewer would be reconnected by gravity downstream of the CSO chamber (MH 360-021). The freeboard at this downstream connection is 2.1 m. Refer to the details of this analysis are included in Appendix 5.4 of Appendix D.

6.5 CSO Analysis A CSO consists of a mixture of sanitary wastewater and stormwater runoff and often contains high levels of floatables, pathogenic microorganisms, suspended solids, oxygen-demanding organic compounds, nutrients, oil and grease, toxic contaminants, and other pollutants.

MOE Procedure F-5-5, Section 6 – Minimum CSO Controls requires that during a seven-month period commencing within 15 days of April 1, all the dry weather flow plus 90% of the volume resulting from wet weather flow above the dry weather flow is captured and treated for an average year.

The main objective of CSO control for the Study Area is to separate the stormwater from the combined sewer system to eliminate basement flooding and combined sewer overflow to Black Creek Drive, thereby also improving water quality. The four CSO structures are located within the Study Area:

• Keele Street/Eglinton Avenue West • Kane Avenue/Dunraven Drive • Keele Street/Hillary Avenue • Hyde Tank Outlet

Figure 6--3 shows the CSO locations within Study Area 3.




Similar to the rainfall used in develoing the WWFMP, a seven-month CSO continuous simulation using 1991 rainfall data provided by City was run using the CS InfoWorks model. From this simulation, the total flow volume, dry weather flow volume, and CSO volume for the existing system condition was determined, and the percentage of wet weather flow volume for the existing condition calculated. For the existing condition, the percentage of volume of CSO from the four locations ranges from 16% to 25%. Proposed basement flooding solutions where simulated in the model and additional elements added, or sizing of existing elements revised, to meet the Procedure F-5-5 objective of keeping overflow to 10% of the volume. Table 6-6 summarizes the CSO analysis for the proposed solution for basement flooding in Study Area 3 that meets the Procedure F-5-5 requirement.

A detailed discussion on the CSO analysis including a complete analysis of CSO is included in Appendix H.

TABLE 6-7 CSO Summary

CSO Location

Total Volume (m3)

in 1991 (7 months)

DWF Volume (m3)

in 1991 (7 months)

CSO Volume (m3) for Existing Condition

% of Volume in WWF for Existing

Condition

CSO Volume (m3) for Trunk sewer

Alternative

% of Volume in WWF for

Trunk sewer Alternative

Keele Street/ Eglinton Avenue West

563,518 404,492 40,125 25 18,908 10

Kane Avenue/ Dunraven Drive

685,191 508,984 28,407 16 17,596 10

Keele Street/ Hillary Avenue

5,953,323 5,102,808 160,818 19 62,055 7

Hyde Tank Outlet – without RTC

221,537 0 80,031 36 17,396 8

Hyde Tank Outlet – with RTC

221,537 0 80,031 36 22,621 10

Note: Hyde Tank Outlet with real-time control (RTC): RTC for 300-mm-pipe from Hyde Tank to Black Creek Sanitary Trunk. If the control condition of the inflow to Hyde Tank is greater than 20 L/s, the door will be closed; otherwise, the door is open.

7. CSO Tank Alternative Analysis

The CSO underground storage tanks are part of the overall solution to be implemented for Study Area 3 and will not resolve all the flooding issues. The proposed CSO tanks are underground storage structures for the temporary storage of excess combined sewage. The tanks are recommended to lower the hydraulic gradeline within the Hilary combined trunk sewer. The underground storage tanks will be located in Nairn Park and Fairbank Memorial Park.

For both locations an inventory of the existing condition of the site has been conducted and included and high level environmental inventory, archaeological desktop assessment, consultation with Parks, Recreation and Forestry and examination of existing policy and permits. Alternative design layouts for each site were developed and evaluated based on the following 5 criteria:

• Technical – ease of construction • Natural – existing terrestrial systems (i.e. existing trees or other features) • Social – the impact on the existing recreational space or land use • Cultural –potential archaeological significant • Economic – the capital cost of construction

An equal weighting factor of 20% was applied to each criteria and none of the criteria was deemed to be more important than the other criteria.

Fairbank Memorial Park Three alternative design layouts were developed for Fairbanks Memorial Park. The layout for Alternative 1 was located in the north end of the Park. Alternative 2 has the layout located east of the existing baseball diamond and Alternative 3 was located in the parking lot of the community centre.

The tank has been sized to operate under a 1:100 year storm event with a storage volume of 3,500 m3, 700 m2 footprint, and average storage depth height of 5 m. A diversion structure has been sized to divert flow during wet-weather conditions from the sewer to the tank. The tank would outlet by means of a pump back to the combined trunk combined sewer at the downstream side of the diversion chamber west of the parking lot. It would take 10 hours (pump rate = 100 l/s) to empty the entire 3,500 m3 volume.

Alternative 1 Figure 7-1 illustrates the layout of the proposed underground tank in Fairbank Memorial Park for Alternative 1 in the north end of the park. Table 7-1 is the detailed evaluation table using the 5 established criteria and comparing all the alternatives for Fairbank Memorial Park.

The advantages of this alternative are:

• There is limited impact to any trees in the park as it utilizes open space • There would be easy access from the street for maintenance


6BCSO TANK ALTERNATIVE ANALYSIS

• The layout has limited impact on the functionality of the park.

The disadvantages of this alternative are:

• There would be disruption of the recreational use of the park during construction • Additional piping through the park is required • The tank would be installed on an existing steep slope – significant earthworks will be

involved.

FIGURE 7-1 Fairbanks Memorial Park – Alternative 1

Alternative 2 Figure 7-2 illustrates the layout of the proposed underground tank in Fairbank Memorial Park for Alternative 2 just east of the ball diamond. Table 7-1 is the detailed evaluation table using the 5 established criteria and comparing all the alternatives for Fairbank Memorial Park.




• There are no removals of any trees in the park as it utilizes the ball diamond


• There would be disruption of the recreational use of the park during construction • The control building for the tank would need to be located outside the ball diamond • Access for maintenance of the tank would be limited due to the baseball diamond • There would be complete disruption of the baseball diamond throughout construction • Design for ventilation and control panels would have to be located off of the limits of the

tank located in the field


Alternative 3 Figure 7-3 illustrates the layout of the proposed underground tank in Fairbank Memorial Park for Alternative 3 in the parking lot of the community centre. Table 7-1 is the detailed



evaluation table using the 5 established criteria and comparing all the alternatives for Fairbank Memorial Park.


• There is very limited impact to any trees, only a few in the boulevard of the parking lot • There is no disruption to the recreational use of the park during construction • There is limited natural impacts due to the existing paving • There is accessibility to the control building for operation and maintenance.


• No on-site parking during construction for the Community Centre, therefore disruption of existing land use during construction.

• The control building would eliminate at least one parking spot




TABLE 7-1 Detailed Evaluation of Alternative for Fairbank Memorial Park

Alternative 1 - North End of Park

Alternative 2 - Southeast Corner

of Park

Alternative 3 - Southwest corner

in Parking Lot

Component Weighting

Factor Raw

Score Weighted

Score Raw

Score Weighted

Score Raw

Score Weighted

Score

Technical - Ease of Construction 20% 4 16 4 16 4 16

Natural - Terrestrial Systems 20% 4 16 4 16 4 16

Social - Impact on Land Use or Recreational Space 20% 4 16 2 8 1 4

Cultural - Archaeology 20% 3 12 3 12 4 16

Economic - Cost 20% 3 12 4 16 4 16

Total Weighted Score 100 18 72 17 68 17 68

Based on the detailed evaluation process all the locations identified are feasible to build, however Alternative 1 was identified as the preferred location for the CSO underground storage tank in Fairbank Memorial Park.

Figure 7-4 shows the preferred location of the CSO underground storage tank for Fairbank Memorial Park. Invert elevations of the inlet and outlet to/from the tank are based on record drawings and are included in conceptual drawings. The exact location and details will need to be finalized during preliminary design.



FIGURE 7-4 Location of CSO Tank – Fairbank Memorial Park Preferred Location

Nairn Park Two alternative design layouts were developed for Nairn Park. The layout for Alternative 1 was located on the east side of the Park. Alternative 2 has the layout located on the west side of the Park.

The underground storage tank in Nairn Park will help lower the hydraulic gradeline in the Hilary Trunk Sewer below basement elevation. The tank will provide 4,000 m3 of storage with an 800 m2 footprint (approximately 20 m x 40 m). The average storage depth of the storage tank is estimated to be 5 m. The existing 1,500 mm Hillary Trunk Sewer runs west along Chudleigh Road north of Nairn Park. The tank would be emptied in approximately 11 hours by pumping to the Hilary trunk sewer. An average pump rate of 100 L/s has been assumed for this calculation.



Alternative 1 Figure 7-5 illustrates the layout of the proposed underground tank in Nairn Park for Alternative 1 in the north end of the park. Table 7-2 is the detailed evaluation table using the 5 established criteria and comparing all the alternatives for Fairbank Memorial Park.


• There is very limited impact to any trees in the park

• There would be limited disruption to the recreational use

• There would be limited natural impacts due to the existing paving or hard surfaces in this area of the park

• The control building can be located in the court area with good accessibility for operation and maintenance.


• There would be disruption of the recreational use of the park during construction



FIGURE 7-5 Nairn Park – Alternative 1

Alternative 2 Figure 7-6 illustrates the layout of the proposed underground tank in Nairn Park for Alternative 2 in the north end of the park. Table 7-2 is the detailed evaluation table using the 5 established criteria and comparing all the alternatives for Nairn Park.


• The control building can be located in the court area with good accessibility for operation and maintenance.


• Existing trees would need to be removed

• Full restoration of trees cannot be accomplished as there can be no point bearing loads (i.e. trees) on the tank



• There would be disruption of the playground during construction

• The tank location would destroy the proposed playground to be newly constructed in Spring 2010

• There is no location near the tank for a control building that would not impact existing trees

FIGURE 7-6 Nairn Park – Alternative 2

Figure 7-7 shows the preferred location of the CSO underground storage tank for Nairn Park. Invert elevations of the inlet and outlet to/from the tank are based on recorded drawings and are included in conceptual drawings. The exact location and details will need to be finalized during preliminary design.



FIGURE 7-7 Location of CSO Tank – Nairn Park Preferred Location

TABLE 7-2 Detailed Evaluation of Alternative for Nairn Park

Component Weighting Factor

Alternative 1 – East End of Park

Alternative 2 - West End of Park

Weighted Score Raw Score

Weighted Score Raw Score

Technical - Ease of Construction 20% 4 16 4 16

Natural - Terrestrial Systems 20% 4 16 3 12

Social - Impact on Land Use or Recreational Space 20% 4 16 3 12

Cultural - Archaeology 20% 4 16 3 12

Economic - Cost 20% 4 16 4 16

Total Weighted Score 100 20 80 17 68




Based on the detailed evaluation process all the locations identified are feasible to build, however Alternative 1 was identified as the preferred location for the CSO underground storage tank in Nairn Park.

Figure 7-4 shows the preferred location of the CSO underground storage tank for Nairn Park. Two alternatives for the inlet and outlet from the tank were investigated for the Nairn Park tank to determine which alternative provided the lowest hydraulic gradeline on the Hilary trunk sewer. The details of this analysis are included in Appendix H. The analysis determined that a new chamber would be constructed at the intersection of Harvey Avenue and Chudleigh Road. A 1,200-mm-diameter diversion sewer, at 1% slope, would convey flow under wet-weather conditions south along Harvey Avenue to the tank. The tank would be pumped out to a new gravity sewer on Harvey Avenue.

Invert elevations of the inlet and outlet to/from the tank are based on recorded drawings and are included in conceptual drawings. The exact location and details will need to be finalized during preliminary design.

8. Recommended Solutions

This section presents the conceptual design of the recommended solution to address the basement flooding and water quality in Study Area 3. The cost estimate along with the mitigation of potential impacts and agency concerns are also outlined in this section.

8.1 Recommended Solutions As part of the basement flooding analysis for Area 3, they study area has been divided into eight (8) sub-areas based on the development and evaluation of alternatives solution. The recommended solution for Study Area 3 showing the major elements such as the storm water trunk sewer, underground CSO storage tanks, and collector storm sewers is shown on Figures 8-1 to 8-9 at the end of this section. The details of each Sub-Area are described in the following sections.

8.1.1 Sub-Area 1 The recommended solution for Sub-Area 1 includes:

• Downspout disconnection • Inlet Controls • Selective removal of catch basins • Addition of catch basins • Addition of new storm sewers


• Downspout disconnection • Inlet Controls • Selective removal of catch basins • Addition of catch basins • Addition of new storm sewers • Storm water trunk sewer


• Downspout disconnection • Inlet Controls • Selective removal of catch basins • Addition of catch basins • Additional sanitary sewer • Addition of new storm sewers • Storm water trunk sewer


7BRECOMMENDED SOLUTIONS






• Downspout disconnection • Inlet Controls • Selective removal of catch basins • Addition of catch basins • Addition of new storm sewers • Underground CSO storage tank • Storm water trunk sewer


• Downspout disconnection • Inlet Controls • Selective removal of catch basins • Addition of catch basins • Addition of new storm sewers • Underground CSO storage tank • Storm water trunk sewer


• Downspout disconnection • Inlet Controls



• Selective removal of catch basins • Addition of catch basins • Addition of new storm sewers • Storm water trunk sewer

8.2 Cost Estimate The cost estimate for the recommended solution is presented in Table 8-1 by Sub-Areas. The costs represent the estimates for constructing the recommended works and a contingency has been added to account for contingencies, engineering services, the disposal of contaminated soils and asphalt having asbestos. The detailed cost estimate is presented in Appendix G, along with assumptions made during the estimating process. The total estimated cost, excluding applicable taxes, for the recommended solution for Study Area 3 is $84,564,000. The cost includes a 40% contingency which incorporates the engineering fees.

TABLE 8-1 Cost Estimate Summary

Sub-Area Cost Estimate ($)

1 $ 4,614,000

2 $ 4,183,000

3 $ 7,975,000

4 $ 5,608,000

5 $ 1,850,000

6 $ 5,265,000

7 $ 9,588,000

8 $ 2,356,000

Stormwater Trunk sewer $43,126,000

Total Cost $84,565,000.00

8.3 Coordination during Detailed Design During the detailed design of the recommended solutions for Study Area 3 coordination and consultation is required with or for the following:

TRCA – Coordination is required with TRCA for any projects located within the TRCAs jurisdiction and the application permits for approvals.

Easements – Easements maybe required for projects and may involve revision to existing easements, new easements, easements through TRCA property. In some instances sub-surface easements maybe required for the stormwater trunk sewer. This is a lengthy process and the approval time should be considered during the detailed design process.

Urban Forestry- Coordination will be required with Urban Forestry for any projects that involve the removal and/or protection of trees.



Parks – Coordination will be required with Parks for permitting and approvals for any projects located on Parks property.

Recreation – Coordination will be required with Recreation if construction will disrupt the existing uses of the park during or after construction.

All utilities (hydro, gas, telecommunications, etc) – Design Initiation Notices will need to be distributed the utility companies to determine conflicts with existing utilities or proposed projects.

Transportation Services – Coordination is required to determine Road Replacement after construction, Traffic Control during construction and any disruption to TTC service during construction.

Stakeholders – Consultation is required with any other stakeholders that maybe effected by the proposed projects.

8.4 Impacts and Mitigation The construction and operation impacts and their associated mitigation measures have been identified for the recommended solution for Study Area 3. The following sub-sections describe these impacts and provide measures to mitigate the impacts.

8.4.1 Potential Impacts and Mitigation Measures of Construction during Construction

Potential impacts due to the construction include impacts to local vegetation (street trees) and storm water quality, and localized increases in truck traffic, vibration, noise and dust. These impacts and measures for mitigating the impacts are outlined in Table 8-2.



TABLE 8-2 Potential Impacts and Mitigation Measures during Construction

Issue Impact Mitigation

Street Trees Construction will occur within road right-of-ways, therefore the potential exists for construction activity to impact street trees.

During detailed design, measures for the protection of street trees, as required by city by-law, will be identified. These measures will include: • Requirement for complete tree inventory

indicating tree species, size, and condition of trees prior to construction

• Tree fencing will demarcate tree protection zones, and tree protection zone signage will be implemented, as specified in the City’s Toronto Tree Protection Policy and Specifications (June 2002)

• A restricted work area will be considered so as to avoid and minimize impacts to tree roots such as soil compaction or other damage.

• Heavy machinery will not be operated and construction materials will not be piled or stored within tree protection zones.

• Excavation activities will not occur within tree protection zones.

• Strict root pruning procedures will be followed where required excavation encounters tree roots.

Habitat Pruning activities required for street trees may disrupt breeding birds or active nests, as well as habitat for common urban wildlife.

During construction, the following measures will be implemented to mitigate, to the greatest extent possible, impacts to bird and animal habitat within tree branches:

• All pruning activities should be done in conformity with standard arboricultural practices and should be supervised by a certified arborist or tree specialist.

• It is recommended that pruning activities be completed outside of the breeding bird season to avoid disturbance to nesting birds (nesting periods are approximately April 1 to September 30).

Stormwater Construction will require excavation and possibly the temporary stock piling of fill material, both of which may cause sediments to wash off-site during storm events.

Sedimentation controls will be in place prior to and during construction. These controls will include: • The installation of a temporary sediment

fence along the boundary of proposed construction.

• The sediment fence will be monitored and maintained in a constant state of good repair.

• Requirement for sediment control in catchbasins and regular clean-up and maintenance of all sedimentation controls





Social/Cultural Environment

Traffic During construction, some lanes of traffic may need to be temporarily closed. During construction, some lanes of pedestrian traffic may need to be temporarily closed.

All lane closures will occur in compliance with all local by-laws and appropriate signage or other safety devices as required by law will be implemented and maintained. Traffic will be maintained with flagging as needed.

Parking During construction on street parking may be temporarily restricted

To manage potential impacts to street parking • Temporary parking will be provided for local

residence during construction.

Access to businesses or residences

Street and driveway access may be limited during short periods of time while construction occurs

To manage potential impacts to street and driveway access:

• Temporary driveway or local road access will be provided for local traffic during construction.

• Measures will be put in place to ensure that every home and business has emergency access to the street.

Vibration Construction activities could create vibrations that could create cracks in the surrounding

The mitigation measure that will be implemented will be to conduct a pre-condition survey of all the homes in the construction area and document any existing cracks in the structure of the homes. If a claim is made by a resident it will then be investigated and mitigation based on the pre-condition survey.

Noise Construction traffic and equipment could create noise.

The mitigation measures that will be implemented include:

• Ensuring all vehicles and construction equipment are equipped with effective muffling devices and are operated in a fashion so as to minimize noise in the project area.

• The City’s noise by-law (By-law 505-2006) will be enforced for all construction activities.

• Construction will normally be carried out Monday to Friday during normal working hours.

Dust and Mud Excavation and filling activities could create more dust and mud than present under ordinary conditions.

Construction best management practices will be used to control dust and mud. The mitigation methods may include:

• Dust control measures such as the application of water or calcium chloride will be undertaken as necessary.

• Public roadways will be kept clean and free of mud by regular street cleaning and/or by tire washing facilities or rumble strips for vehicles exiting construction sites.





Archaeology Potential impact to archaeological resources will be assessed through the completion of a Stage 2 Archaeological Assessment during detailed design.

If construction activities, such as excavation, uncover what appear to be human remains or materials that may have archaeological significance, then the City will cease construction and contact the Ministry of Culture immediately for an assessment of the potential impacts.

Park Access and/or Recreational use during Construction

Limited access or use of Fairbank Memorial and Nairn Park may create specific concerns during the construction.

In order to mitigate these impacts, the following controls will be utilized: Construction activities could potentially be scheduled off-season to have the least impact. Pedestrian walkways, if interrupted, will be re-routed around the construction Construction sites will be secured at all times with access restricted to construction personnel.

Groundwater Groundwater may be encountered during construction and a permit to take water maybe required.

Based on the depth of the excavation, groundwater may be encountered .During detailed design a geotechnical investigation will be conducted to determine the impact and design requirements (i.e. shoring, permit to take water)

Black Creek Flow Regime

No impact since flood plain analysis included peak flows from uncontrolled 1:100 year storm and Regional storm

None required.

8.4.2 Potential Impacts and Mitigation Measures during Operation The following Table 8-3 outlines the potential impacts and mitigation measures during operation of the conveyance control structures.

TABLE 8-3 Potential Impacts and Mitigation Measures during Operation

Criteria Impact Mitigation

Social/Cultural Environment

Odour The conveyance controls will operate entirely below street-level, as part of the sewer system, and therefore will not emit any additional odours.

In locations where odour issues pre-exist, maintenance hole covers will be sealed with the use of sewer guards. The odour emitted will be regulated and an odour filter system will need certification of approval from the MOE

Maintenance Requirements

Wherever possible, the infrastructure will be designed to minimize maintenance requirements, however in some cases, where pumps or other mechanical features must be incorporated, periodic maintenance may be necessary.

To mitigate impacts of maintenance activities: • Maintenance activities will be undertaken by

the City and will therefore occur after advanced notice through signage, and with as little disruption to local roads or traffic as possible.

• Attempt shall be made to locate maintenance access so as to minimize impacts to pedestrian and vehicular traffic



TABLE 8-3 Potential Impacts and Mitigation Measures during Operation

Criteria Impact Mitigation

Vibration and Sound The operation of the recommended solution will be located underground.

The recommended solution is located underground and has limited mechanical operations, therefore vibration and sound will not be experience at the service.

Park and Recreational Use

The recommended solution will limit the available space for planting trees in the park, immediately above the underground structure.

Landscape design will maximise tree planting around the underground structure and will include an appropriate recreational use.

Water Quality The operation of the recommended solution will improve local water quality in Black Creek

In order to mitigate these impacts, the following controls will be utilized: Installation of primary sedimentation at the outlet of the storm water trunk sewer.



FIGURE 8-1 Preferred Key Solution Map




FIGURE 8-2 Sub – Area 1 Recommended Solution



9. Consultation Program

As part of the planning process, a carefully considered public consultation program was put in place that involved identifying distinct target groups for the public consultation and associated consultation objectives. Accordingly, a contact plan was enunciated for each of the target groups. This exercise helped the project team ensure that all defined groups and their needs were considered and addressed. Table 9-1 briefly summarizes the consultation process mapping that was carried out. The public consultation related notices and correspondence is included as Appendix F.

TABLE 9-1 Summary of Consultation Plan

Target Group Objectives Contact Plan

Agencies • Provide project commencement Information

• Provide continual updates • Seek comments and feedback • Obtain in principle approvals as applicable

• Notice of Project Commencement – mail out

• Ongoing correspondence as needed • Meetings as needed • Notice of Completion

Public • Provide project commencement information

• Provide continual updates • Seek comments and feedback

• Notice of Project Commencement – Advertisement

• Public Information Centre • Ongoing correspondence as needed • Notice of Completion

Special Stakeholders

• Provide project commencement information

• Provide continual updates • Seek comments and feedback • Obtain closure on issues

• Notice of Project Commencement – Advertisement

• Public Information Centre • Correspondence and meetings with

Special Interest groups as needed • Notice of Completion

Utilities • Provide project commencement information

• Periodically provide updated project milestone information

• Seek project specific inputs prior to or during preliminary design stage

• Ensure subsequent coordination as needed

• Notice of Project Commencement – Mail out

• Ongoing notices and correspondence • Issues tracking and meetings as

needed • Notice of Completion

9.1 Public and Agency Consultation At the beginning of the study a notice of commencement was published in the local newspaper and mailed to review agencies to inform them of the project and solicit comments. The following other methods were used:


8BCONSULTATION PROGRAM

• Mailing Lists – A mailing list was created which includes contacts for all relevant review agencies as well as local interest groups and ratepayer associations within the Study Area. In addition, all members of the public who requested to be added via telephone, email or comment sheet were included. All persons on the mailing list were sent letters prior to each of the public open house events.

• Public Open Houses – Two open house events were held throughout the course of the Study. They consisted of a drop-in centre with display panels, a presentation followed by a question and answer period, and an opportunity for the public to speak with project staff. Handouts were made available and consisted of: Basement Flooding Fact Sheet, Basement Flooding Protections Subsidy Program, Drain Grant Application, City Sewer System Guide and comment forms.

• Newspaper Advertisements – Advertisements were placed in the local newspaper to announce the commencement of the EA and prior to each open house event. The advertisements invited the public to attend the event and identified ways to obtain more information.

• Direct Mail – Notices were mailed to residents and businesses within the study boundaries using Canada Post two weeks prior to the first Open House event. Review Agencies were also notified.

• Project Website – At the onset of the study, a website was launched by the City to provide the public with additional means of obtaining information about the project. The project website advertised all notices and was updated throughout the study. The link to the website is as below, Study Area 3:

http://www.toronto.ca/involved/projects/basement_flooding/index.htm

Copies of all public consultation related materials and correspondence are provided in Appendix F.

9.1.1 Public Notification Notice of Study Commencement A Notice of Study Commencement was advertised in the January 4 and January 11, 2008 editions of the York Guardian newspaper. The notice was also mailed to the local business and residents within the affected wards.

Public Open House #1 In late October 2009, a notice advertising the first Public Open House was distributed door-to-door via Canada Post to approximately 16,500 residents and businesses within the Study Area. Those individuals who had requested to be added to the study mailing list were also notified. On the flipside of the mailed notice, event information was translated into three languages: Portuguese, Spanish, and Italian. The notice introduced the study, explained the objectives, referred to the Municipal Class EA process, and instructed how the public could contribute input. Advertisements for the event appeared in the October 23, 2009 and October 30, 2009 editions of the York Guardian (south).


http://www.toronto.ca/involved/projects/basement_flooding/index.htm


Public Open House #2 Advertisements for the second Public Open House appeared in the December 4, 2009 and December 11, 2009 editions of the York Guardian (south) newspaper. All residents, businesses, and review agencies on the project mailing list were notified. The notice provided background information, identified the proposed underground storage tanks, and instructed how the public could contribute input.

9.1.2 Agency Notification The Notice of Study Commencement was distributed in early January 2008 to all relevant review agencies to inform them of the nature and scope of the project. In addition, letters were issued to the following aboriginal contacts to notify them of the project:

• Indian and Northern Affairs Canada • Ontario Secretariat for Aboriginal Affairs • Mississauga’s of the New Credit First Nation

Notices were also sent in October 2009 and December 2009 inviting these groups to attend the Public Open Houses and inform them of the recommendations and design options for the preferred alternative solutions.

Following the Notice of Commencement, a number of response letters were received from various agencies each indicating their respective levels of interest in this study and whether they would like to be kept informed of project updates. Letters were received from CNR, the TRCA, and TTC.

A representative from the TRCA, along with staff from the City’s Parks, Forestry, and Recreation division were also included as members of the internal project team.

TRCA Meeting – October 6, 2009 On October 6, 2009 the City and CH2M HILL meet with representatives from TRCA to discuss the background of the project and the proposed solutions for the study area and discuss the approval requirements and any potential conflicts with other TRCA projects. The outfalls located within Study Area 3 are located within the concrete channelized section of Black Creek Drive. TRCA has no special requirements for a new outfall at this location since the new outfall will not impact the existing channel banks. However, any connection to the concrete section of Black Creek Drive should be investigated to ensure that the new connection does not undermine the channel concrete liner. It will need to be determined during detailed design who owns the channelized section of Black Creek Drive for any easements. A copy of the minutes from this meeting are included as part of Appendix F.

9.2 Public Open House 9.2.1 Public Open House #1 Public Open House #1 was held on November 4, 2009 from 7:00 p.m. to 9:00 p.m. at St. John Bosco Catholic School located at 75 Holmesdale Road. The purpose of the meeting was to:



• Introduce and provide background information on the study • Explain the Municipal Class EA Process • Identify the causes of basement flooding and surface flooding during extreme events • Make recommendations to reduce future flooding • Outline the next steps in the study

The format of the meeting included a drop-in centre with display panels. A presentation was also given followed by a question and answer period. People were then given the opportunity to speak one-on-one with project staff and view displays about area-specific recommendations.

A comment sheet requesting input on the study was provided to participants along with a postage paid envelope. Participants were asked to submit their comments to the City within a two-week period following the Open House. Thirty-five members of the public signed in at the meeting and three comment sheets were returned and the comments addressed. A total of 3 public comments sheets were received and copies can be found in Appendix F along with the presentation, and minutes. Sheet 1 is from a resident in Sub-Area 4, and there comment can be resolved through other City programs in conjuction with the Study Area 3 solutions. Sheet 2 is from a resident in Sub-Area 1 and deals predominately with backyard flooding. Sheet 3 is also from a resident in Sub-Area 1 and is a statement confirming their experience with basement flooding. An information package was prepared for residents who indicated interest in the study but could not attend the event. In total, 11 packages were sent. Minutes from the presentation and Questions and Answers (Q&A) portion of the meeting are also available on the project website.

9.2.2 Public Open House #2 The second Public Open House was held on December 14 from 7:00 p.m. to 9:00 p.m., at Fairbank Middle School located at 2335 Dufferin Street. The purpose of the meeting was to:

• Provide project overview • Present alternative designs for underground storage tanks • Provide opportunity for questions about proposed works • Outline the next steps of the study process

Like Public Open House #1, the format of the meeting was an informal drop-in centre with display panels, a presentation and question and answer period.

The comment sheet, which was provided to attendees, requested input on the alternative designs for underground storage tanks at Nairn Park and Fairbank Memorial Park. Comments were requested within a two-week period following the event. A total of eight members of the public signed in at the Open House and no comment sheets were submitted to the City.

Minutes from presentation and Q&A portion of this meeting are available on the project website. A copy of the minutes and the presentation is included in Appendix F.




9.3 Councillor Briefings The Study Area covers three city wards: Ward 12 (York South-Weston), Ward 15 (Eglinton-Lawrence), and Ward 17 (Davenport). Councillors for each Ward were notified of the study. Their offices were also invited to attend each of the Public Open House events. Staff from Toronto Water provided councillor briefings regarding background information, project status, and the public consultation approach.

All background information related to the study, meeting material, project updates and staff contact information were posted on the project website at www.toronto.ca/involved/projects. This website was regularly updated as the study progressed.

9.4 Notice of Completion A Notice of Completion was published in the York Guardian February 17 and February 24, 2011, and was also distributed to agencies and individuals on the mailing list, or who indicated an interest in the study. This report has been made available to the public at the Evelyn Gregory Branch Public Library, The Maria A. Schuka Branch Public Library, and the Oakwood Village Branch Public Library, and at Metro Hall, 55 John Street, Toronto. This report will be available for review for 30-days.

During the 30-day review period, the public has an opportunity to review this Environmental Screening Report and provide additional comments and input. If concerns cannot be addressed through discussions with the City of Toronto, a person/party may request the Minister of the Environment to order the project to comply with Part II of the EA Act. If Part II Order requests are received, the proponent and the concerned parties can work together to help resolve conflicts. If conflicts cannot be resolved, the Minister of the Environment will make a decision as to whether or not the Part II Order should be granted and an Individual Environmental Assessment completed. If there are no Part II Order requests during the 30-day review period, the proponent may proceed with the project.

Requests for a Part II Order must be received by the Ministry by March 21, 2011 and can be submitted by a written request to the Minister at the following address:

The Honourable John Gerretsen Minister of the Environment 12th Floor, 135 St. Clair Avenue West Toronto, Ontario M4V 1P5

Copies of the Part II Order request should also be sent to:

Maogosha Pyjor, Public Consultation Co-ordinator Public Consultation Unit Metro Hall, 55 John Street Toronto, Ontario M5V 3C6

http://www.toronto.ca/involved/projects/basementhttp:/www.toronto.ca/involved/projects/basement_flooding/sa_11_n_12.htmhttp:/www.toronto.ca/involved/projects/basement_flooding/sa_11_n_12.htm_flooding/sa_11_n_12.htm

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