Welcome

Investigation of Flooding in Area 2(Leaside Area)

Public Information Centre #2

View displays and discuss the study with project staff

Feel free to ask questions and fill out a comment sheet

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Purpose of Tonight’s Meeting

• Overview of problems in the study area

• Outline the factors contributing to basement and surface flooding

• Present the options considered

• Present the recommended solutions

• Outline the next steps

• Hear from you! Your input is very important

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Purpose of Our Study and Study Area• Investigation includes:

Examine existing stormwater drainage, combined and sanitary sewer systems and identify the causes of basement flooding and/or surface flooding in Area 2; and,

Make recommendations to reduce the risk of future flooding in Area 2.

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Sewer Infrastructure• Area 2 is serviced by a

combination of sanitary, combined and storm sewers.

Combined Sewer System

Separated Sewer System

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Our Basement Flooding FindingsUnder normal rainfall events, the storm, sanitary and combined sewer systems operate as designed. However, during extreme storms, the following takes place:•Stormwater flows exceeds the capacity of the storm and combined sewers and overloads the system.

•Water remains on the surface and flows along roads and creeks.

•Water can enter the basements from the surface via doors, window wells and reverse-slope driveways.

•At low lying areas, water accumulates (ponds) on the surface and streets and enters the sanitary sewer system through manhole covers. This causes the sanitary sewers to surcharge and potentially backup into basements.

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Our Basement Flooding Findings (Cont’d)

• Excess stormwater can enter the sanitary sewer system during extreme events. • The ground and soils can become saturated with water

that can enter the sanitary sewer system through cracks, holes or damaged joints in pipes and maintenance holes located underground.

• In low lying areas, water accumulates (ponds) on the surface and can enter the sanitary sewer system through manhole covers.

• There are some homes with downspouts and/or foundation drain connections to the sanitary sewer system. These are direct connections and allow stormwater to enter the sanitary sewer system.

• If stormwater enters basements through doors, window wells or reverse slope driveway drains, it often enters the basement floor drain which is connected to the sanitary sewer system.

• Once the sanitary sewer system is surcharged, there is a risk of backup into basements.

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Causes of Basement Flooding(Separated System)

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Causes of Basement Flooding

Note: typical connections shown, however private drainage systems can be more complex and each one is unique.

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Options Considered for Reducing Flooding

Source control measures involve managing stormwater where it originates (roofs, roads, driveways), before it enters the City’s sewer systems.

These measures include:Downspout disconnection

Rain barrels

Catchbasin inlet controls

Surface flow path diversion

Bioretention units

Sanitary sewer rehabilitation

Source Controls Conveyance Controls

These measures include:Alternate road cross-sections (grassed ditches / swales)

Bioretention units and bioswales

Overland flow control

Sewer pipe diversion, replacement or twinning

Sewer separation in combined sewer areas

End-of-Pipe Controls

These measures include:Surface dry ponds

Surface wet ponds

Underground storage tanks or underground storage pipes

Conveyance control measures help to control stormwater as it travels along the drainage system (in pipes or along the road).

End-of-pipe control measures control stormwater and CSOs just before it is discharged to a watercourse (stream, river, or lake).

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Evaluation of Options

Natural Environment• Potential Impact on Terrestrial Systems (Vegetation, Trees,

Wildlife)• Potential Impact on Aquatic Systems (Aquatic Life and

Vegetation, Surface Water, Groundwater)• Soil and Geology

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Social Environment

• Effect on Urban Greenspace (Parks, Ravines, Open Spaces)

• Disruption to Existing Community During Construction (Traffic, Noise)

• Disruption to Existing Community Post Construction (Visual Impact, Odour, Safety)

• Archaeology, Heritage Resources and First Nations

Technical Considerations

• Feasibility of Control Measure (Available Space, Accessibility, Constructability)

• Effectiveness in controlling basement and/or surface flooding

• Impact on Upstream and Downstream Infrastructure

• Operations & Maintenance RequirementsCost Considerations

• Capital Costs

• Operating & maintenance costs

Economic

The following criteria were used to evaluate options and identify the recommended solutions:

Recommended Solutions

Install catchbasin inlet control devices at identified locations

Increase the number of catchbasins in low lying areas

Roof leader disconnection to limit stormwater entering the sanitary or

storm sewer system

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Recommended Solutions

• Replace existing storm and/or sanitary sewers with larger diameter sewers at various locations where required to provide additional conveyance capacity in the sewer system.

What Does it Involve?• Road excavation within the City’s Right-of-Way• Removal of old sewer and structures (manholes & catchbasins)

and disconnection of sewer service line(s)• Placement of new sewer, reconnection of sewer service line(s)• Some tree removals and replacement (after construction is

completed) may be required• Restoration of road upon completion of construction.

Storm and/or Sanitary Sewer Replacement and Upgrades

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Recommended Solutions

• Construct new storm sewers at various locations to separate combined sewers and provide additional conveyance capacity in the sewer system.

What Does it Involve?• Road excavation within the City’s Right-of-Way• Placement of new storm sewer(s)• Disconnection and reconnection of existing sewer service lines

(if necessary)• Some tree removals and replacement (after construction is

completed) may be required• Restoration of road upon completion of construction.

New Storm Sewers for Sewer Separation

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Recommended Solutions

• Replace a portion of an existing sewer with a larger ‘superpipe’ to provide temporary storage of wet weather flow. Once sewer capacity is available, the ‘superpipe’ is drained by gravity.

What Does it Involve?• Road excavation within the City’s Right-of-Way• Potential removal of old sewer and structures (manholes &

catchbasins) and disconnection of sewer service line(s)• Placement of new sewer and potential reconnection of sewer

service line(s)• Some tree removals and replacement (after construction is

completed) may be required• Restoration of road upon completion of construction.

Underground In-Line Storage

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Area 2 – Recommended Infrastructure

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Area 2 - Summary of Recommended Infrastructure

• Recommended infrastructure needed to provide basement flooding protection includes:

– New storm sewers to complete sewer separation on Craig, Bessborough, Donlea, Rumsey, Hanna, Vanderhoof, Flemming, Cameron, Astor, Sutherland, Markham and Esandar.

– New storm sewers to provide additional capacity on McRae, Burnham, Heath, Bennington Heights, Moorehill, Mallory, Rykert, and Broadway.

– New in-line storage storm sewers to store excess wet weather flow on Southlea, Bessborough, Moore and Pottery.

– Additional catchbasins or catchbasin inlet controls on Millwood, Vanderhoof, Laird, Commercial.

– New in-line storage sanitary sewer on Bennington Heights to store excess wet weather flow.

– New sanitary sewers to provide additional capacity on Burnham, Lumley and Heath.

– Inflow/ infiltration investigation for Copeland Area to identify sources of infiltration and inflow into the sanitary sewer system.

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Next StepsAnticipated

TimelineWhat Will Happen?

After Tonight’s Meeting

After tonight’s meeting, the Study Team will review and consider your comments to finalize the preferred solution for Area 2.

Late 2014A Notice of Study Completion will be issued and a Project File Report will be placed in local libraries for a 30 day public review period.

After Completion of the Environmental Assessment Process

Implementation of the Recommended Projects – inclusion of the recommended projects in the City’s 5 Year Basement Flooding Protection Project List. Implementation timing will depend on:

• Sequencing of projects from completed basement flooding EA studies, as per City Council approved criteria.

• Coordination with other planned infrastructure projects (e.g. Transportation and utilities projects) in the area as per the City’s Multi-Year Capital Coordination Plan.

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Thank You for Attending

We welcome your feedback. Please fill out the comment sheet provided.Following this PIC, the study team will review and consider your comments in

the final selection of the preferred alternatives.

Contact InformationFor more information on this study, or to provide your comments or be placed on the

project mailing list, please contact:

Josie Franch, Public Consultation Unit55 John Street, Metro Hall, 19th Floor, Toronto, ON M5V 3C6

Phone: 416-338-2859, E-mail : jfranch@toronto.ca

Fax: 416-392-2974, TTY: 416-338-0889

Website: http://www.toronto.ca/involved/projects/basement_flooding/sa_2.htm

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