Area 38 pic 1 final presentation

Welcome!

Investigation of Basement Flooding and Stormwater

Runoff Quality Control Study Area 38

Master Plan Class EA

Public Information Centre #1

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

We’re hosting this meeting to provide you with information about Basement Flooding

Investigations for Area 38.

Here you will learn about:

• Project background, study scope and approach,

• Study Area,

• Potential causes of basement and surface flooding, including locations,

• Possible alternative solutions and evaluation criteria,

• Next steps.

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Background

• Large storm events in 2000, 2002,

2005 and 2006 caused basement

and surface flooding across the

City.

• Through the Basement Flooding

Protection Program, the City is

developing plans to reduce flooding

risk in certain areas.

Maintenance hole lid damage from Black Creek flooding Example of flooded basement

Example of ponding

Example of storm sewer surcharging

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Background

• Study Area 38, located in the Etobicoke Creek

area, has experienced basement and surface

flooding during past extreme storms in 2005,

2012 and 2013.

• The study area is based on local sewer

system and generally bounded by: • Rathburn Road – North

• Highway 407 – East

• Lakeshore Boulevard – South

• Etobicoke Creek – West

• The most recent flooding event was in July

2013 where 140 properties or 5% of all

properties in this study area reported flooding.

• Reports of flooding were predominantly

concentrated in residential neighbourhoods

north and south of Rathburn Road and Bloor

Street.

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Purpose of Study

• Determine the contributing factors for surface and basement flooding in Area 38.

• Address flooding by improving infrastructure and where feasible, improve the

quality of stormwater runoff before it goes to Etobicoke Creek and Renforth

Creek.

• Recommend solutions to improve the City’s storm and sanitary sewer systems

including overland drainage routes.

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What This Study Will and Will Not Cover

Will Cover: Public Lands - Any improvements to the sewer and drainage system to be

made within the City’s property such as parks, roads and sewer infrastructure.

Will Not Cover: 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

drainage catchbasins

• Foundation drains

• Sump pumps and backwater valves

• Private tree roots and what you put

down the drains (fats, oils, grease, etc)

• Disconnecting downspouts

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• Storm sewers (minor system) convey up to 1 in 2 year storms.

• Streets (major system) convey major storms that exceed the storm sewer capacity.

• Temporary ponding on streets is expected during major rain storms.

Design Standards:

• Water level in the storm & sanitary sewer is below basement elevation.

• Street flow depth should not exceed the street right-of-way limits.

Storm System Drainage

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Investigating Basement Flooding: Steps Involved

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Data Collection and Inventory of Existing Conditions

Preliminary Assessment Report

Identify Causes of Flooding and Potential Solutions

Identify & Recommended Solutions/Overall Strategy

Develop Conceptual Design for Preferred Solutions

Prepare & File EA Report

WE ARE HERE

PIC #2

PIC #1

Municipal Class EA Process

• The City must meet the

requirements of Ontario’s

Environmental Assessment (EA)

Act for infrastructure projects.

• The EA process is an opportunity

for the public and agencies to

provide input.

• This project requires completion of

Phases 1 and 2 of the Class EA

process. We are in the early stages

of Phase 2.

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PHASE 1

Identify and Describe the Problem or Opportunity

PHASE 2A

Complete Study Area Inventory, Identify

Alternative Solutions

Mandatory Review

Agency/Public

Notification

30 Day Review Period

Notice of Study

Commencement

Late in the Fall 2015

PHASE 5

Complete Drawings & Documents, Proceed to Construct, Operate and

Monitor Project

PHASE 2B

Evaluate Alternative Solutions & Establish the

Preferred Solutions Strategies

Mandatory Review

Agency/Public Consultation

PIC #2

Fall 2016

Mandatory Review

Agency/Public Consultation

PIC #1

May 18, 2016

Existing & Future Land Use / Natural Environment

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“The study area is

highly urbanized

with vegetation

communities

clustered around

Etobicoke Creek.”

Existing Land Use Future Land Use Natural Environment

Natural environment

features include Etobicoke

Creek, Renforth Creek and

vegetation communities

clustered around these

water courses. Natural

environment features

including species at risk

will be further defined

based on desk top and

field investigations

Typical Causes of Basement Flooding

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Area 38 Preliminary Causes of Flooding

Based on 2015/2016 field investigations and analysis,

potential causes of Area 38 flooding could be influenced in

part by the following:

• Road sags, private lot grading issues and low lying areas-

Lack of adequate overland flow routes could lead to

excessive ponding and flooding of adjacent properties.

• Maintenance hole covers with perforated lids are

potential source of inflow into the sanitary network.

• High levels of infiltration entering parts of the system in

some areas.

• Localized extreme storms that overwhelm the existing

sewer.

• High levels of inflow through perforated manholes

entering in creek valley

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Perforated maintenance hole lid

Road sag

Connected downspout

Inefficient ditching and driveway culverts

Private lot grading issues

Basement Flooding

by Cluster

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• Area 38 flooding problems are

generally confined to five

cluster areas.

• The study will also review non-

cluster areas to confirm if

adequate design standards are

in place.

Summary of Survey Results to date

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Majority of

homeowners who

responded live in

detached homes

with basements

Found areas of

flooding not

previously

identified

About 30% of

respondents

indicated sewage

like odour with

past flooding

About 60% of

respondents do

not have back-

water valves

Significant

percentage of

downspouts have

been disconnected

from the sewer

Public Feedback

What we heard from

you…….

About 50% of the

respondents have

experienced

basement flooding

• Of approximately 4400 properties, over 180 survey forms were received from home owners.

• This information was used to update flooding data bases and validate flooding areas – clusters.

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Homeowner Measures to Control Flooding - Isolating your

home’s plumbing from the City’s sewer systems

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Methods for Reducing Basement Flooding & Improving

Stormwater Runoff Quality

Source Controls:

• Source control measures involve managing stormwater

where it originates (roofs, roads, driveways), before it

enters the City’s sewer pipes.

Conveyance Controls:

• Conveyance control measures help to control stormwater

as it travels along the drainage system (in pipes or along

the road).

End of Pipe Controls:

• End-of-pipe control measures control stormwater just

before it is discharged to a watercourse (stream, river, or

lake).

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Potential Solutions – Source Controls

Residents can help reduce runoff – the water that flows from hard surfaces into the sewer system. Naturalizing

your property lowers the risk of basement flooding and contributes to improving stormwater runoff quality.

Rain Barrels Tree Planting Downspout

Disconnection

Reduce Toxins Permeable Paving

• Eliminate

pesticide/fertilizer use

• Do not let household

chemicals such as paint,

oil, grease, salt, soap, etc.

wash to the storm sewer

• Pick-up pet waste

Soakaway Pits Green Roofs

Rain Gardens

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Potential Solutions – Source Controls

Sealing

Maintenance

Hole Covers

Additional source control options:

• Sewer Maintenance and Rehabilitation

Involves:

• Sanitary Sewer: CCTV, smoke/dye tests, sewer cleaning, relining, and repair

• Storm System: Street sweeping, seasonal leaf pick-up, catchbasin vacuum

cleanouts

Surface Flow Path

Diversion Pervious Pavement

These measures can also help reduce the amount of runoff entering the sewer system.

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Potential Solutions – Conveyance Controls

Description

• A vegetated depression and underground

trench designed to filter stormwater runoff

to remove pollutants and promote

infiltration/evapotranspiration

What Does it Involve?

• Diversion of small overland or piped

drainage areas for small storm events

• Excavation of a trench with specific soil

mixture, surface plantings and underdrain

within an open area such as a boulevard

or park

Description

• Maintain/enhance existing ditches

and culverts which slow down

surface water and encourage

infiltration/filtration

• Retrofit existing concrete curb and

gutter streets with grassed

ditches/swales if opportunity exists


• Excavation of ditches and installation

of shallow culvert pipes where

appropriate

Road Cross-Section Retrofits (Ditches)

(Improve Stormwater Runoff Quality) Local Bioretention Filters

(Improve Stormwater Runoff Quality)

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Increase Number of Catchbasins

(Controls Basement Flooding)

Overland (Major System)

Control



• Addition of “speed bump” or “curb cut” to

redirect overland flow to strategic locations

• Interception of road or boulevard flows to

dedicated major system sewer with large inlet

grate or “curb drain”


• Minor street excavation for installation of

new catchbasin(s) and connection to

storm sewer

• Curb replacement and road restoration

Description

• The diversion of surface

drainage away from low

lying areas that have no

direct outlet to reduce

surface ponding depths

Description

• Where the storm

sewer has existing

capacity, add more

catchbasins to

capture more flow

from the surface

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Parking Lot Retrofit for Surface

Storage


Catchbasin Inlet Controls



• A plastic or metal plate / device installed

inside the catchbasin outlet (not visible from

surface)

• Minimal effort and time to install

• Keeps more water on the surface

Description

• Installation of ICDs in parking lots to

store stormwater on surface

• Installation of roof drain controls to store

stormwater on large flat roof areas


• Retrofit of City-Owned property (where

physically possible)

Description

• Installation of inlet control devices

(ICDs) on catchbasins to limit

release into the storm sewer

system to control back-up

(surcharge)

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Adding New Sewers (Twinning)


Replacement of Existing Storm

and/or Sanitary Sewers


Description

• Increase the size of the sewer pipe by

replacing the old sewer with a larger pipe


• Road excavation within City limits

• 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) and restoration of road

and boulevard

Description

• Increase the capacity of the sewer system by

adding another sewer pipe in addition to the

existing pipe


• Road excavation within City limits

• Replacement of old structures (manholes &

catchbasins) and reconnection of sewer

service line(s), if necessary

• Placement of new sewer, reconnection of

sewer service line(s) and restoration of road

and boulevard

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Potential Solutions – End of Pipe Controls

Wet Pond/Wetland

(Controls Basement Flooding and

Can Improve Runoff Quality)

Dry Pond


Description

• An engineered surface depression that controls

the quantity of inflowing stormwater through

storage and slow release to the receiving

system

• Typically fills with water during extreme storm

events and drains within 24 to 48 hours or less


• Excavation and shaping of a suitable open

space

• Addition of inlet/outlet structures

• Restoration and landscaping; signage

Description

• An engineered pond or wetland with a

permanent water surface that controls the

quantity and quality of inflowing stormwater

through storage and slow release to the

receiving system


• Excavation and shaping of a suitable open

space

• Addition of inlet/outlet structures

• Restoration and landscaping (aquatic and

side-slope)

• Infrequent maintenance (sediment removal)

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Potential Solutions – End of Pipe Controls

Oil & Grit Separator

(Improves Stormwater Runoff

Quality)

Underground Storage Tank

(Controls Basement Flooding & Can

Improve Stormwater Runoff Quality)

Description

• An underground tank or pipe that controls the

rate of inflowing sanitary or stormwater

through temporary detention and slow release

to the receiving sewer, reducing the potential

for flooding


• Excavation and construction of tank or pipe,

including inlet and outlet structures

• Infrequent maintenance (monitoring, clean-

out)


• Similar to a manhole, minor street

excavation for installation of structure

• Road restoration

• Annual maintenance (vacuum clean-

out)

Description

• An underground

separation tank that

takes the place of a

conventional manhole

and provides a measure

of treatment for small

drainage areas

Evaluation Criteria for Evaluating Potential Solutions

The following criteria will be used in evaluating alterative solutions and identifying the recommended

strategy:

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Criteria Description

Preferred Solutions

Natural Environment Impact on aquatic resources such as receiving

water quality, groundwater fisheries and

floodplain

Impact on terrestrial environment such as street

trees, parks and habitats including Species at

Risk

Soils and Geology

Technical Effectiveness in reducing Basement Flooding

Ease to implement - constructability

Upstream/downstream impacts

Operations and Maintenance Requirements

Social/Cultural Impacts on existing and future land use

Temporary impact to residents and businesses

during construction – access, noise, dust

Impact on archaeological and heritage features

Economic Capital cost

Operating/maintenance cost

Cost per benefiting home (value for money

spent)

Existing Storm Sewer and Sanitary Sewer System Existing Storm Sewer System Existing Sanitary Sewer System

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What Happens Next

For more information on this study, or to provide your comments, please contact:

Josie Franch, Senior Public Consultation Coordinator (Public Consultation Unit)

55 John Street, Metro Hall, 19th Floor

Toronto, ON M5V 3C6

Phone: 416-338-2859

Email: [email protected]

Website: www.toronto.ca/bfea

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Spring 2016

•See project website for a copy of the display materials

•Receive public comments by June 1, 2016

•Following this PIC Project Team will review and consider your comments in the evaluation of alternative solutions

Fall/Winter

2016

•PIC #2 will present the recommended solutions

•Prepare EA Report

2017

•File EA Report for 30-day public review period.

•Conceptual Design

•Detailed Design including approvals

mailto:[email protected]

Government & Nonprofit

Area 38 pic 1 final presentation