WelcomeBasement Flooding & WaterQuality Improvements Study Area 39Municipal Class Environmental Assessment StudyPublic Information Centre #1

Date: June 13, 2016Time: 6:00 pm to 8:00 pm

Meeting Overview

This Public Information Centre (PIC) focuses on:

• Background on the sanitary and stormwatersystems in Study Area 39

• The Class Environmental Assessment process

• Locations of and factors contributing to surface and basement flooding in Study Area 39

• Solutions being considered to reduce flooding in Study Area 39

• Draft evaluation criteria for assessing alternative solutions

Background and Purpose of the Study

Study Area 39, located in Etobicoke, has experienced basement and surface flooding under severe storms for several years. The most recent storm event in July 2013, had 144 properties report flooding (5% of the properties in Study Area 39).The purpose of this study is to identify the preferred solution to reduce the risks of basement and surface flooding in Area 39 as well as to help improve quality of stormwater runoff before it flows to Berry Creek.

The study will:• Confirm the problem by identifying where basement and surface

flooding occurs and the causes of the flooding

• Identify opportunities for improvement by assessing feasible alternative solutions

• Recommend the preferred solution (i.e. combination of projects) to improve the City’s storm and sanitary systems, including overland drainage routes

Study Area 39

Class Environmental Assessment Process

• To meet the requirements of Ontario’s Environmental Assessment (EA) Act, the City is undertaking a Master Plan in accordance with the Municipal Engineers Association’s Municipal Class EA.

• The Master Plan involves completion of Phases 1 and 2 of the Municipal Class EA.

• Identify the problemor opportunity

• Notice of Commencement Nov., 26, 2015

• Study Newsletter No. 1 December 2015

Phase 1

Weare

here

30 DayReview

Design and Construction

• Design, construct and monitor

• Incorporate Comments

• Complete the Master Plan, Fall 2017

Documentation

• Develop computer models to analyze causes of flooding and impact of surface runoff on water quality

• Develop and Evaluate alternative solutions

• Establish the Preferred Solution (combination of projects)

• Develop Conceptual Designs

• Study Newsletter No. 3 Spring 2017

• PIC #2 Spring 2017

• Collect and review background studies, information on existing conditions

• Conduct field surveys

• Identify flooding locations, and causes

• Develop draft evaluation criteria

• Study Newsletter No. 2 June 2016

• PIC #1 June 2016

Phase 2

• Urbanization has increased surface runoff and decreased infiltration into the ground. This increases the potential for the transport of pollutants in surface runoff from streets, parking lots and other hard surfaces.

• Stormwater collects pollutants (e.g., oil, dirt, debris) as it travels through the stormwater drainage system. The degraded water quality may impact:

• Fisheries and other aquatic life• Sediment quality and benthic invertebrates• Fish consumption advisories• Loss of aquatic habitat• Nutrient enrichment, including nuisance algal growth

• These potential impacts are not only a concern in Berry Creek, but also downstream where the local waterways discharge to Lake Ontario.

Stormwater Quality

Sanitary System Map

Storm System - Dual Drainage SystemMajor (streets) and Minor (sewer pipes)

• 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.

Storm Minor System Map

Storm Major System Map

Area 39 Historical Basement Flooding

Typical Causes of Basement Flooding

• Sewer system becomes overwhelmed with stormwater during severe storm events

• Poor lot grading or drainage • Water entering basements through doors,

window wells, cracks in the foundation, and reverse slope driveways

• Water accumulating in low-lying areas and entering the sanitary sewer system through manhole covers (backs-up the sanitary system)

• Fats, oils, grease buildup in sewers causing blockages

• Homes with downspouts, sump pumps and foundation drains connected to sanitary sewer contribute to excessive flow to the sanitary system

• High water table interacting with sewer system• Excess flow in the trunk sewer causing

surcharging in the local sewer system

Factors Contributing to Basement Flooding in Area 39

There are a number of reasons why surface and basement flooding can occur during large rain events. Some of the primary reasons include:

Reverse Slope Driveway with poor drainage

Reverse slope driveway with poor drainage

Water entering basement through back door

Factors Contributing to Basement Flooding in Area 39

• Customer service reports from the City’s database were reviewed, and causes of flooding were determined for each of the 246 flood reports within Area 39.

• Residents of the study area took part in an online survey to provide further input on past flooding.

Methods for Reducing Basement Flooding and Improving Stormwater Runoff Quality

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

Conveyance ControlsMeasures to control stormwater as it travels along the sewer system (in pipes or along the road).

End-of-Pipe ControlsMeasures to control stormwater just before it is discharged to the receiver (watercourse, trunk sanitary or storm sewer).

Watermain

Storm Lateral

Water Service

Roof Downspout

Catch Basin

Fire Hydrant

Rear-yard Catchbasin

Sanitary Lateral

Storm Lateral

Areas of Responsibility

CityAny improvements to the sewer and drainage system are to be made within the City’s property such as parks, roads and sewer infrastructure. Property OwnerEach homeowner is responsible for the operation and maintenance of drainage systems on private property including:

• 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

Property Owner - Potential Solutions

Disconnecting downspouts

Maintaining front and rear-yard drainage or driveway catchbasins

Using rain barrels

Installing permeable

paving

Open joint pavers Porous asphalt

Pervious concrete Turf grid

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

Lot grading

Installing backwater

valve

Disconnecting foundation drains

from sanitary sewer and installing /

maintaining sump pumps

Potential Solutions – Source Control

Source control solutions being considered for the City sewer system include:

Surface flow path diversion

Sealing or replacing sanitary manhole

covers

Catchbasinmodification -

add catchbasins / change catchbasin

type / use inlet control devices

Local Bioretention Filters (Improves Stormwater Runoff Quality )DescriptionA 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

Potential Solutions – Conveyance Control

Overland Flow Control (Controls Basement Flooding)DescriptionThe diversion of surface drainage away from low lying areas that have no direct outlet to reduce surface ponding depths.

What Does it Involve?• 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”

Potential Solutions – Conveyance Control

Rehabilitating Sewer Systems(Controls Basement Flooding)

DescriptionRepair defects (cracks, joints) in the sewer system to reduce groundwater infiltration and stormwater inflow.

What Does it Involve?• Access through existing manholes • Slip lining and point repairs

Replacement/Addition of Storm and/or Sanitary Sewers (Controls Basement Flooding)DescriptionIncrease the capacity of the sewer system by replacing the old pipe with a larger pipe or adding additional sewer pipes.

What Does it Involve?• Road excavation within City limits• Removal of old sewers and structures (manholes &

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

line(s) and restoration of road and boulevard

Potential Solutions – End-of-Pipe Control

Wet Pond/Wetland (Controls Basement Flooding and Improve Stormwater Runoff Quality)DescriptionAn 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.

What Does it Involve?• Excavation and shaping of a suitable open space• Addition of inlet/outlet structures• Restoration and landscaping (aquatic and side-slope) • Infrequent maintenance (sediment removal)

Underground Storage Tanks and Pipes (Controls Basement Flooding and Improves Runoff Quality)

DescriptionAn 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.

What Does it Involve?• Excavation and construction of tank

or pipe, including inlet and outlet structures

• Infrequent maintenance (monitoring, clean-out)

Potential Solutions – End-of-Pipe Control

Dry Pond (Controls Basement Flooding)DescriptionAn engineered surface depression that provides storage for inflowing stormwater and slow release to the receiving system. Typically fills with water during extreme storm events and drains within 24 to 48 hours or less.What Does it Involve?• Excavation and shaping of a suitable open space• Addition of inlet/outlet structures• Restoration and landscaping

Oil and Grit Separators (Improves Runoff Quality)DescriptionA structure that consists of one or more chambers that remove sediment, screen debris, and separate oil from stormwater. Oil and grit separators are installed underground as part of the storm sewer system.What Does it Involve?• Excavation and installation of oil and grit separator, including

inlet and outlet structures• Infrequent maintenance (monitoring, clean-out)

Draft Evaluation Criteria for Alternative Solutions:

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:

Economics Capital cost Operating and

maintenance costs

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

Socio-Cultural Land use impacts (parks,

ravines, open spaces) Disruption to existing

community during construction (traffic, noise)

Disruption to existing community post construction (visual impact, odour, safety)

Potential impacts to archaeological and cultural resources

Impacts to First Nations

Natural EnvironmentPotential impacts on: Terrestrial systems

(vegetation, trees, wildlife)

Aquatic systems (aquatic life and vegetation)

Surface and groundwater

Soil and geology Receiving water quality

Next Steps

After today’s meeting:• Review comments received today• Develop and evaluate alternative solutions and recommend the preferred

solution• Present alternatives evaluation and preferred solution at Public Information

Centre #2 in the Spring of 2017 for feedbackWe welcome your feedback. Please fill out the comment sheet provided.

Josie FranchPublic Consultation UnitCity of Toronto55 John Street, Metro Hall 19th Floor, Toronto, ON M5V 3C6Phone: 416-338-2859 Fax: 416-392-2974 TTY: 416-338-0889Email: jfranch@toronto.caVisit: toronto.ca/bfea