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PUBLIC INFORMATION CENTRE #1October 4, 2016, 6pm – 8pm

Basement Flooding Remediation and Water Quality Improvement Master Plan Class EA Study Area 34

WELCOME

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WELCOMEPURPOSE OF TONIGHT’S MEETING

• Introduce the problem and study objectives

• Present information on the causes of flooding and the impacts of stormwater runoff

• Present possible alternative solutions and criteria for evaluating the alternatives

• Outline the next steps in the study process

• Hear from you! Your input is very important.

Basement Flooding Remediation and Water Quality Improvement Master Plan Class EA: Study Area 34

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WELCOMEPURPOSE OF THIS STUDY

• Examine existing stormwater drainage and sanitary sewer systems and identify the causes of basement flooding and/or surface flooding (severe ponding on streets during extreme storms).

• Assess control measures to improve the quality of stormwater runoff as per the City’s Wet Weather Flow Master Plan.

• Make recommendations to:• Reduce the risk of future flooding• Improve the quality of stormwater runoff before it is

discharged to Taylor-Massey Creek and its tributaries


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AREAS OF RESPONSIBILITY


Watermain

Storm Lateral

Water Service

Roof Downspout

Catch Basin

Fire Hydrant

Rear-yard Catchbasin

Sanitary Lateral

Storm Lateral

City’s Responsibility:Public Lands – Any improvements to the sewer and storm drainage system to be made within the City’s property such as parks, roads, and sewer infrastructure.

Property Owner’s Responsibility:Private Property Improvements – Each homeowner is responsible for the operation and maintenance of drainage systems on private property which includes:

• Lot grading• Front and rear-yard or driveway

catchbasins• Foundation drains• Sump pumps and backwater valves• Private tree roots• What you put down the drain (fats, oils

grease, etc.)• Disconnecting downspouts

• The City of Toronto must follow the Municipal Class Environmental Assessment (EA) process to meet the requirements of Ontario’s EA Act for all infrastructure projects.

• The EA Act requires the “protection, conservation and wise management of the environment” while undergoing infrastructure enhancements.

• The EA process is also an opportunity for the public and agencies to provide input throughout the project.

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MUNICIPAL CLASS ENVIRONMENTAL ASSESSMENT (EA) PROCESS


Public Information Centre 1: Fall 2016

• Overview of Study• Problem Statement• Existing Conditions• Alternative Solutions• Evaluation Criteria• Next Steps

Identification of Problem or Opportunity

Evaluation of Alternative Solutions & Identification

of Recommended Solution

Selection of Preferred Solution Following

Consultation Activities

Master Plan is Filed and Posted for Public

Viewing: Winter 2017

Phase 1 Phase 2

Public Information Centre 2:

Summer/Fall 2017

• Evaluation of Alternative Solutions

• Identification of Preferred Solutions

• Next Steps

Notice of Study Commencement

Notice of Public Information

Centre 1

Notice of Public Information

Centre 2

Ongoing Public & Agency Consultation throughout the

Study

Notice of Study Completion

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We are here

Master Plans are conducted under the framework of the Municipal Engineers Association (MEA) Class EA process. They are long-range plans that identify infrastructure requirements for existing and future land use within a larger study area, through the application of EA principals.

MASTER PLAN PROCESS


• Collecting and reviewing background data on land use, population, soil conditions, sanitary sewer and storm drainage systems, flooding history, and operation/maintenance records.

• Conducting surveys to inventory the number of roof leaders disconnected; survey catchbasins, dual manholes, and CSO structures; identify low lying areas; and conduct an inventory of storm outfalls.

• Developing computer models to: - Analyze the causes of basement and surface flooding and predict flows under various weather conditions, and; - Assess the impacts of stormwater runoff on water quality in Taylor-Massey Creek.

• Developing and receiving feedback on potential measures to address the issue of basement and surface flooding in the study area and to improve stormwater runoff water quality before it is discharged to the environment (1st Public Information Centre).

• Presenting the recommended solution (at 2nd Public Information Centre) and finalizing the Master Plan based on input from the public and agencies.

We are here

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STUDY OVERVIEW


The many steps involved in the study before solutions can be recommended include:

Problem Statement• On August 19, 2005 the City of Toronto suffered from flooding of residents’

homes and damage to watercourses due to a large storm event.

• The City of Toronto has developed a work plan for an engineering review to address the basement flooding concerns across 67 areas within the city.

• Study Area 34 has been subject to basement and surface flooding incidents during major historical storm events, resulting in damage to properties, infrastructure, and natural features.

Objectives• Identify potential causes of basement and surface flooding as they relate to the City’s storm and sanitary drainage

infrastructure;• Identify flooding interactions between the sanitary and storm drainage systems;• Establish evaluation criteria;• Propose surface and basement flooding remediation and control alternatives;• Propose works to improve the quality of water discharged to the environment;• Identify and evaluate control alternatives to recommend a preferred solution; and,• Prepare an infrastructure implementation master plan.

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PROBLEM STATEMENT AND STUDY OBJECTIVE


• Urbanization has not only increased surface runoff and decreased infiltration into the ground, but has also increased the potential for the transport of pollutants via surface runoff from streets, parking lots and other hard surfaces.

• Stormwater runoff often contains heavy metals, bacteria, nitrates/sulfates, salt, sand, grit, oil/grease, trash, and other pollutants.

• Pollutants in the stormwater runoff adversely impact the water quality of the receiving watercourse, which affects fisheries, wildlife, recreational uses, visual aesthetics, etc.

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Taylor-Massey CreekPHOTO: Robert Taylor. Taylor Creek, Taylor Creek Park, Toronto_1176

STORMWATER RUNOFF QUALITY


• Area 34 is located in southwest Scarborough and is serviced by a combined sewer system, as well as separate storm and sanitary systems.

• This area has experienced basement and surface flooding incidents during severe storm events on May 12, 2000, August 19, 2005, July 31, 2012, May 28, 2013 and July 8, 2013.

Characteristics Study Area 34Study area size 1,354 hectaresNumber of properties 11,152

Sanitary trunkMassey Creek Relief Sanitary Trunk

Victoria Park Combined TrunkGodfrey-Fowler Combined Trunk

Major receiving watercourse Taylor-Massey CreekNumber of storm outfalls 46Number of combined sewer outfall (CSO) structures 41

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Study Area 34

Massey Creek

WELCOMESTUDY AREA 34


• Storm sewers (minor system) convey frequent, small storms. • Streets (major system) convey major storms that exceed the storm sewer capacity.• Temporary ponding on streets is expected during major rain storms.

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STORM DRAINAGE SYSTEM


Sanitary/Combined Sewer Storm sewer to

convey frequent, small storms

Street to convey stormwaterflows above storm sewer design capacity

Street right-of-way

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POTENTIAL CAUSES OF FLOODING


Under normal rainfall events, the storm, combined and sanitary sewer systems operate as designed. However, during extreme storms, the following takes place:

• Connected downspouts contribute to stormwater flows exceeding the storm, combined and sanitary sewer capacity and overloading the system.

• Water remains on the surface and flows along roads and creeks. Surface water may enter basements through basement doors, window sills, reverse-sloped driveways and through sewer connections.

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

• The ground becomes extremely wet and groundwater enters the sanitary/combined system through cracks in the pipes underground. This can also contribute to backup of the sanitary/combined sewers.

Other factors causing sewer backups:• Foundation drains connected to the sanitary/combined sewer system;• Cross-connections between the sanitary and storm sewer systems, and; • Oil/grease dumped into sanitary sewers causing blockages.

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POTENTIAL CAUSES OF FLOODING


General measures are presented. Detailed alternative measures will be developed on a case-by-case assessment of the City’s storm drainage and sanitary/combined sewer networks. This will take place at a later time in the Master Plan Class EA process and will be presented at the second Public Information Centre.

• Source ControlsMeasures involve managing stormwater where it originates (roofs, roads, driveways), before it enters the City’s storm and sanitary systems.

• Conveyance ControlsMeasures to control storm and sanitary flows travelling along the sewer systems (in pipes or along the road).

• End-of-Pipe ControlsMeasures to control storm and sanitary flows before discharging to the receiver (watercourse, trunk storm sewer or trunk sanitary sewer).

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MEASURES TO REDUCE BASEMENT AND SURFACE FLOODING RISKS AND IMPROVE STORMWATER RUNOFF QUALITY


Potential measures that will be considered to upgrade and expand the City’s existing storm drainage and sanitary/combined sewer networks include:

Maintaining front and rearyard drainage and

driveway catchbasins

Maintaining front and rearyard drainage and

driveway catchbasins

Installing and maintaining backwater valves and

sump pumps

Installing and maintaining backwater valves and

sump pumps Installing permeable

pavingInstalling permeable

pavingDisconnecting roof

downspoutsDisconnecting roof

downspouts

Naturalizing the property (rain gardens, green roofs)Naturalizing the property

(rain gardens, green roofs) Installing rain barrelsInstalling rain barrels

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POTENTIAL SOLUTIONS: PROPERTY OWNER


Residents can help reduce runoff – the water that flows from hard surfaces into the sewer system. Naturalizing your property can improve stormwater runoff quality and may reduce the risk of basement flooding.

Source control solutions that can be implemented by property owners include:

• Eliminating pesticide/fertilizer use

• Ensuring household chemicals such as paint, oil, grease, soap, etc. do notwash into the storm sewer

• Picking up pet waste

Surface Flow Path Diversion Surface drainage is directed away from low lying areas that have no direct outlet to reduce surface ponding depths. “Curb cuts” can be added to redirect overland flow to strategic locations.

Sealing Maintenance Hole Covers Maintenance hole covers with perforations in low lying and ponding areas are sealed to reduce the amount of stormwater runoff entering the sanitary/combined sewer system and reduce the risk of sanitary/combined sewer capacity overload.

These source control options help to:

reduce the risk of basement flooding

improve stormwaterrunoff quality

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POTENTIAL SOLUTIONS: SOURCE CONTROL


Replacement of Existing Storm and/or Sanitary SewersExisting storm and/or sanitary sewers with inadequate capacities to convey the required flows are replaced with larger pipes.

Construction of New Sewers Existing sewer pipes remain in place and a new sewer pipe is installed to provide additional flow capacity.

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These conveyance control options help to:



POTENTIAL SOLUTIONS: CONVEYANCE CONTROL


Oversized Storage PipesNew oversized pipes are constructed to temporarily store water and help relieve overloading of the storm sewer system.

Catchbasin Inlet Control Catchbasin inlet controls are installed to limit stormwaterrunoff entering the storm system.

Increasing CatchbasinCapacity For existing storm sewers having capacity, the number of catchbasins are increased to capture more flow from the surface.

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Infiltration/Exfiltration SystemsStormwater conveyed in storm sewers can be released underground via perforations (small holes) in the pipe to recharge the water table.

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Bioretention UnitsBioretention units are plant and soil based, and provide low impact treatment and infiltration, for treating stormwater runoff in developed areas.

BioswalesBioswales are landscape elements designed to remove silt and pollution from stormwater runoff. These are designed with specific soil mixtures, surface plantings and underdrain within open areas such as ditches, boulevards or parks.

Pervious PavementPervious pavement is designed to allow percolation or infiltration through the surface into the soil below where the water is naturally filtered and pollutants removed.

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Underground Storage Tanks/Shafts

Dry Ponds Temporary storage of flows can be provided underground using tanks/shafts (for storm and sanitary/combined systems), or above ground using dry ponds (storm drainage only). Once there are adequate flow capacities in the sewer systems, the flows from these storage facilities will be gradually released. Furthermore, underground storage tanks or shafts provide treatment for stormwater through settling.

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These end of pipe control options help to:



POTENTIAL SOLUTIONS: END-OF-PIPE CONTROLS


Wet Ponds/ Constructed WetlandsWet ponds and constructed wetlands are basins that have a permanent pool of water throughout the year to store runoff during and after storm events. They treat and filter stormwater runoff through settling and through nutrient uptake by plants and other aquatic organisms.

Oil/Grit SeparatorsAn oil/grit separator is an underground structure connected to the storm sewer to improve stormwater quality by removing contaminants such as grease, oil, mud, sand and trash.

Wet ponds/constructed wetlands help to:



Oil/grit separators help to:

improve stormwaterquality

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POTENTIAL SOLUTIONS: END-OF-PIPE CONTROLS

Natural EnvironmentPotential impacts on:• Terrestrial systems (vegetation,

trees, wildlife)• Aquatic systems (aquatic life

and vegetation)• Surface and groundwater• Soil and geology• Receiving water quality

Socio-Cultural• Land use impacts (parks, ravines,

open spaces)• Disruption to existing community

during construction (traffic, noise) and post-construction (visual impact, odour, safety)

• Potential impacts to archaeological and cultural resources

• Impacts to First Nations

Technical • Effectiveness in reducing surface

and basement flooding and improving stormwater runoff quality

• Feasibility of implementation (available space, accessibility, constructability, approvals)

• Potential impacts on upstream, downstream, and surrounding area infrastructure

• Impacts on operating and maintenance requirements

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EVALUATION CRITERIA


Economic• Capital cost• Operating and

maintenance costs

Alternative solutions will be evaluated based on their ability to address the Study’s purpose, stakeholder input, and their potential impacts.

Evaluation criteria being considered include:

Thank you for attending this Public Information Centre.

Next Steps• Please fill out a comment sheet.• The study team will review and consider your comments in the evaluation of alternative measures.• The recommended solution will be presented at the Public Information Centre #2 (Summer/Fall 2017).

Contact InformationIf you have additional questions or comments please contact:

Ms. Mae LeePublic Consultation Unit, City of Toronto Metro Hall, 19th Floor, 55 John Street Toronto, ON M5V 3C6Tel: 416-392-8210Fax: 416-392-2974TTY: 416-338-0889Email: [email protected]: http://www.toronto.ca/bfea

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