Date: April 7, 2014 By: Peter Loukes Environmental Service - - PowerPoint PPT Presentation

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date april 7 2014 by peter loukes environmental service
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Date: April 7, 2014 By: Peter Loukes Environmental Service - - PowerPoint PPT Presentation

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Date: April 7, 2014 By: Peter Loukes Environmental Service Department . . 1 Background Program focus on wastewater system flooding risk reduction: - sources of water on municipal land entering collection system; - sources of water from

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Date: April 7, 2014 By: Peter Loukes Environmental Service Department

. 1 .

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Background

Program focus on wastewater system

flooding risk reduction:

  • sources of water on municipal land entering

collection system;

  • sources of water from private property entering

collection system e.g. Downspouts connect to sanitary system;

Monday , April 7, 2014 2 Presented by Peter Loukes

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Sources of Water to Sanitary System – Municipal Land

Monday , April 7, 2014 3 Presented by Peter Loukes

Element component Strategy & Status Sanitary Manholes Roads Seal manholes & design standards (ongoing & changed) Rear yard easements Surveying for needed repairs (ongoing) Water courses and valley lands Surveying for needed repairs (ongoing) Areas on road prone to water ponding Install manhole plugs in lid or install dishes / tubs under manhole lid (changed) Cracks in Sewer or lateral Main Line & Laterals TV camera work and spot repairs (ongoing)

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Sources of Water to Sanitary System – Private Property

Monday , April 7, 2014 4 Presented by Peter Loukes

Element Strategy & Status Commercial areas parking lots Change in design standards (changed) Seal manholes (changed) Lateral connections and leaks TV work and repairs (ongoing, requires customer participation) e.g. Grandview area pilot lateral lining Other Connections to laterals: Downspouts Driveway catch basins Sump pumps Smoke and water testing confirmation

  • Sanitary System Downspouts Disconnection Program
  • may require disconnection by Property Owner
  • May require redirecting by Property Owner
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Environmental Service Department

Monday , April 7, 2014 5 Presented by Peter Loukes

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Downspout Disconnection Program Overview

 Background  Pilot Sanitary System Downspout Disconnection

Program Findings

 City-wide Sanitary System Downspout Disconnection

Program

 Phase 1 Program update  I/I Initiatives/Programs Recap  Preventive Measures for Future Development  Conclusion  Questions

Monday , April 7, 2014 6 Presented by Peter Loukes

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Background

 Older areas within City (built before 1980’s) may have home roof

downspouts incorrectly connected to sanitary sewer system.

 Problems with these direct connections:

  • Increase the risk of basement flooding;
  • Major source of extraneous sanitary inflow;
  • Currently illegal (Prohibited under By-Law).

 To resolve the issues, City of Markham approved Pilot Sanitary

System Downspout Disconnection Program in Grandview Area

  • f Thornhill, April 29, 2008. The program was completed in 2012

including one year of post flow monitoring.

Monday , April 7, 2014 7 Presented by Peter Loukes

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Background con’t

 Goals of the Sanitary System Downspout

Disconnection Program:

  • Reduce risk of wastewater based basement

flooding.

  • Protect sanitary sewer system by reducing

extraneous inflows.

  • Enforce existing City of Markham Sewer By-Law

#436-86

Monday , April 7, 2014 8 Presented by Peter Loukes

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Pilot Program - Results

  • 766 homes.
  • 45 homes (6%) identified with downspouts

connected to sanitary sewer system.

  • achieved 100% disconnection compliance.
  • 40-50% reduction in peak inflow &

infiltration (I/I) rates (pre to post disconnection) within local sanitary sewers.

Monday , April 7, 2014 9 Presented by Peter Loukes

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City-wide Program

 Base on pilot findings & success, City-wide Sanitary

System Downspout Disconnection Program approved by Council Mar 19, 2013.

 City-wide Program focusing on risk reduction in areas

with elevated risk of wastewater based basement

  • flooding. (based on modelling)

 Multi-phases

[Estimated to have seven phases implemented over ten year period (2013-2023)]

Monday , April 7, 2014 10 Presented by Peter Loukes

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City-wide Program con’t

 Phasing & priority base on :

  • Flow modelling data
  • Flow monitoring data
  • Past flooding records
  • All on-going programs/initiatives within Markham

 Overall program implementation timing subject to

change based on annual risk evaluation & annual Council Reports.

Monday , April 7, 2014 11 Presented by Peter Loukes

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Monday , April 7, 2014 12 Presented by Peter Loukes

Areas of Interest

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City-wide Program Components

Monday , April 7, 2014 13

  • I. Public Communication
  • II. Site Investigation
  • III. Disconnection of identified

downspouts

  • IV. Financial Assistant Package
  • V. Post Flow monitoring & Reduction

Verification

Presented by Peter Loukes

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  • I. Public Communication

Monday , April 7, 2014 14

City of Markham web page

Testing Stage:

  • Notification Letter
  • Brochure on investigation & testing works

Disconnection Stage:

  • Notice of Disconnection letter to affected residence
  • Brochure detailing methods of disconnecting the

downspout & Financial Assistant Package.

  • Additional website information on how to disconnect

the downspout

Presented by Peter Loukes

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  • II. Site Investigation

Monday , April 7, 2014 15

Preliminary Property Investigation (Lot Survey)

Smoke Testing (Sanitary and Storm Sewer System)

Presented by Peter Loukes

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  • II. Site Investigation

Monday , April 7, 2014 16 Presented by Peter Loukes

Water Testing (Inconclusive downspouts from smoke testing)

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  • III. Disconnection of Identified Downspouts

Monday , April 7, 2014 17

Notifications mailed to specific properties advising of disconnection needs

Brochure will be distributed to affected residents detailing disconnection methods

Financial Assistant Package (FAP) will be provided.

Presented by Peter Loukes

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  • IV. Financial Assistant Package (FAP)

Monday , April 7, 2014 18

City will reimburse 80% of cost for completing downspout disconnection where connected to Sanitary Sewer System, up to a maximum of $500;

The City will reimburse 100% of cost for a rain barrel purchased by home owners who are asked to disconnect, up to a maximum of $150.

Presented by Peter Loukes

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  • V. Post Flow Monitoring

Monday , April 7, 2014 19

Flow monitoring for one year period

Evaluate the effectiveness of disconnection program.

Basis for risk analysis to identify & prioritize future initiatives for that area.

Presented by Peter Loukes

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Monday , April 7, 2014 20 Presented by Peter Loukes

Location: Thornhill

  • No. of Properties: 2,256 properties

Program Period: 2013-2016

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Phase 1 Program –Investigation Findings

Monday , April 7, 2014 21

16 homes with downspouts connected to Sanitary Sewer System

51 other sources of extraneous flow found

Presented by Peter Loukes

  • 1. Road CB connect to sanitary sewer

4

  • 2. Sanitary MH Defects (cracks, hole, improper

cover lid) 5

  • 3. Uncapped lateral clean out

17

  • 4. Driveway drains, private CB, side drains, stairwell

drains, and rear drains connection to sanitary sewer 13

  • 5. Potential sump pump connections

3

  • 6. Weeping tile connections

2

  • 7. Disconnected DS not properly capped

2

  • 8. Others

5

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Phase 1 results

 Water testing provided minimal benefits for locations

found inconclusive with smoke testing

 Based on results we are looking at removing the water

testing part of program.

 This will reduce the total program forecast by $0.38M

from $2.56M to $2.18M

Phase 1

$0.81M

Future Phases

$1.37M

Total Program Forecast$2.18M

 Funding for future phases will be considered as part of

the annual capital budget process

Monday , April 7, 2014 22 Presented by Peter Loukes

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Phase 1 results (continued)

 This will permit larger areas to be tested each year  Program will be reduced from seven phases to five

phases

 Now implemented over eight year period (2013-2020)

instead of ten year period (2013-2023)

Monday , April 7, 2014 23 Presented by Peter Loukes

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I/I Initiatives/Programs Recap

Monday , April 7, 2014 24

I/I Risk Reduction Initiatives/Programs:

  • i. Sanitary System Downspouts Disconnection

Program

  • ii. Pursue repairing any other sources of I/I public or

private

  • iii. Sanitary MH inspections
  • Focus on MH within valley, watercourse, backyard

easement & road sag.

  • Evaluate condition & needs for plugging MH

covers

  • iv. Manhole sealing during roads reconstruction
  • v. Service lateral lining and repair

Presented by Peter Loukes

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Preventive Measures for Future Development

Monday , April 7, 2014 25

Design Standard Update

  • Locate private sanitary MH at high ground areas or islands.
  • MH should locate outside Regional Flood Plain or elevated

to min. 100 yr water level within flood plain.

  • Seal MH cover at low point of R.O.W.
  • Bituminous seal tape around MH rings & section joints
  • Clay/collar plug in bedding of sewers below groundwater

table.

  • Rubber apron to grip pipe & MH interface.

Areas undergoing reconstruction:

  • Follow updated Design Standard
  • Fix existing defects

Presented by Peter Loukes

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Conclusion

Monday , April 7, 2014 26

Sanitary System Downspout Disconnection Program is part of Basement Flooding Risk Reduction Strategy

Looking at removing I/I sources that provide the biggest benefit for least cost

Trying to reduce relative risk of wastewater based flooding throughout City

Area phasing to reduce level of perceived risk based on flow modeling & flow monitoring results

Presented by Peter Loukes

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Thank you for your attention.

Monday , April 7, 2014 27 Presented by Peter Loukes

Any Questions