Dain City Inflow and Infiltration Investigation and Remediation Action Plan

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In response to resent flooding events in the Dain City neighborhood, the City of Welland has introduced several initiatives to better understand the causes of flooding and to develop implementable solutions to reduce the risk of future flooding.

The City of Welland is embarking on a plan to locate and address sources of high Inflow and Infiltration, and further create a plan to mitigate issues to reduce stress on the wastewater systems, and reduce the volume of wastewater that Niagara Region treats.

Over the next few months, thorough investigations will take place in the affected Dain City areas to ultimately create and execute a Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

City staff and GM BluePlan are working on the following tasks this fall 2020:

        • Public Outreach and Resident Feedback
        • CCTV Sewer Inspection
        • Sanitary Sewer Flow Monitoring
        • Curbside Property and Neighbourhood Survey
        • Fog and Dye Testing


Research is KEY to a thorough PLAN. The following information describes key factors of the beginning stages of the Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

Public Outreach and Data Collection: Dain City residents in the affected areas are asked to provide information through a survey. Data collected from the survey is a key tool to preparing and executing a Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

Inflow and Infiltration Investigation: The Dain City Inflow and Infiltration Investigation and Remediation Action Plan investigation will identify unwanted sources of I&I entering into the city’s wastewater collection system. All residents in the I&I investigation areas will receive a letter of notification via mail if or when this procedure will occur. A thorough investigation will help develop appropriate and realistic remediation strategies to reducing and eliminate sources of I&I entering the system.

Fog and Dye Testing: Fog and Dye testing might be conducted in the affected Dain City areas. All residents in the Fog and Dye testing areas will receive a letter of notification in the main if or when this procedure will occur.

What is fog testing? The fog test consists of blowing a harmless coloured vapour into the sewer manholes and pipes and observing where the fog exits from the system. The fog is expected to exit primarily out of manholes on the street and the sewer plumbing stack at the top of your house. It is also possible for fog to exit stormwater catch basins and roof downspouts at the side of a house. The fog used in the test has no odour, isn’t harmful to your health, and will disappear after a few minutes.


In response to resent flooding events in the Dain City neighborhood, the City of Welland has introduced several initiatives to better understand the causes of flooding and to develop implementable solutions to reduce the risk of future flooding.

The City of Welland is embarking on a plan to locate and address sources of high Inflow and Infiltration, and further create a plan to mitigate issues to reduce stress on the wastewater systems, and reduce the volume of wastewater that Niagara Region treats.

Over the next few months, thorough investigations will take place in the affected Dain City areas to ultimately create and execute a Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

City staff and GM BluePlan are working on the following tasks this fall 2020:

        • Public Outreach and Resident Feedback
        • CCTV Sewer Inspection
        • Sanitary Sewer Flow Monitoring
        • Curbside Property and Neighbourhood Survey
        • Fog and Dye Testing


Research is KEY to a thorough PLAN. The following information describes key factors of the beginning stages of the Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

Public Outreach and Data Collection: Dain City residents in the affected areas are asked to provide information through a survey. Data collected from the survey is a key tool to preparing and executing a Dain City Inflow and Infiltration Investigation and Remediation Action Plan.

Inflow and Infiltration Investigation: The Dain City Inflow and Infiltration Investigation and Remediation Action Plan investigation will identify unwanted sources of I&I entering into the city’s wastewater collection system. All residents in the I&I investigation areas will receive a letter of notification via mail if or when this procedure will occur. A thorough investigation will help develop appropriate and realistic remediation strategies to reducing and eliminate sources of I&I entering the system.

Fog and Dye Testing: Fog and Dye testing might be conducted in the affected Dain City areas. All residents in the Fog and Dye testing areas will receive a letter of notification in the main if or when this procedure will occur.

What is fog testing? The fog test consists of blowing a harmless coloured vapour into the sewer manholes and pipes and observing where the fog exits from the system. The fog is expected to exit primarily out of manholes on the street and the sewer plumbing stack at the top of your house. It is also possible for fog to exit stormwater catch basins and roof downspouts at the side of a house. The fog used in the test has no odour, isn’t harmful to your health, and will disappear after a few minutes.


  • The City of Welland has retained GM BluePlan Engineering Ltd. to conduct an inflow and infiltration investigation and remediation action plan. This is one of many initiatives the city is undertaking to better understand the causes of flooding within the Dain City neighborhood and to develop implementable solutions to reduce the risk of future flooding. This plan was initiated due to basement flooding that is occurring in the Dain City neighborhood during large rain events. Please take a few minutes to complete this voluntary questionnaire, which will benefit the study and help us gain a better understanding of basement flooding issues in the area.

    Take Survey
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