Frequently Asked Questions about Third Line & Coronation Park - Mid Halton Outfall Pipe

What is under construction at Coronation Park?

Halton Region, with approval from the Town of Oakville, Ministry of the Environment and Climate Change, Ministry of Natural Resources, Conservation Halton and other agencies is constructing a 60-metre deep shaft at this location. This shaft is part of the construction of a new deep effluent outfall (underground tunnel) that will carry treated wastewater from the Mid Halton Wastewater Treatment Plant to Lake Ontario. The effluent outfall will be constructed below the road surface by tunnelling and will extend 2.1 km offshore.

The project was identified, through the Class Environmental Approval process to meet the requirements of the Ministry of the Environment and Climate Change and further to protect the quality of water in Lake Ontario. Extensive effort was made during the design process to minimize disruption to Coronation Park during construction. This included several consultations with the Town of Oakville and Conservation Halton.

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Why is a wooden fence necessary at Coronation Park?

Wooden hoarding (fencing) is standard for this type of construction activity to ensure safety of the general public and minimize disruption to park users and neighbouring residents.

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Why is the hoarding painted?

The hoarding (fencing) has been painted green to minimize visual impact and ensure it would fit into the local landscape.

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How long will the hoarding be up at the Park?

The project restoration is scheduled to be finished by the summer of 2017. The hoarding (fencing) will remain in place until this time to ensure the safety of the general public and to minimize disruption to park users. Following final restoration, the hoarding will be removed.

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Will Coronation Park be closed at any time?

Only the area within the hoarding (fencing) will be off limits during construction to ensure the safety of the general public. All other areas of Coronation Park will remain open, including the lakeside Waterfront Trail, splash pad and playground, and parking area adjacent to the hoarding.

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Will there be noise or vibration during construction?

Construction of the Coronation Park shaft is expected to create some noise and vibration. The contractor’s working hours at the Coronation Park site must comply with Town of Oakville regulations, including the Noise By-law. In general, work at the Coronation Park site will be restricted to between the hours of 7 a.m. and 7 p.m. Subsurface tunnelling activities will take place beyond these hours but should not impact park users or surrounding residents.

Solar-powered monitoring stations have been installed in Coronation Park and along Lakeshore Road and Third Line in order to monitor noise and vibration. The contractor was required to install these stations in order to determine both background (pre-construction) and construction-related levels of noise and vibration. Should noise and vibration exceed levels identified in the construction contract documents or the Town of Oakville Noise By-Law, the contractor will be required to modify their activities.

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What about dust, dirt and traffic control?

Strabag Inc. is the general contractor for this project. They are contractually obligated to ensure dust, dirt and traffic delays on Lakeshore Road (in the immediate vicinity of Coronation Park), Third Line and the North Service Road are kept to a minimum for the duration of the construction period. While there will be occasional lane restrictions or re-routing of traffic, these will be kept to a minimum and the public will be provided with notice of any potential traffic delays.

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What is the project schedule?

Date Project milestone
August 2014 to November 2014 Mid Halton Wastewater Treatment Plant shaft construction
October 2014 to January 2015 Coronation Park Shaft site
Summer 2015 to Winter 2016 Tunnelling Offshore
December 2015 Complete all tunnel mining
2015 and Spring 2017 Marine work
December 2015 to August 2016 Tunnel Lining Onshore
May 2016 to September 2016 Tunnel Lining Offshore
June 2016 Complete permanent shaft works at Mid Halton WWTP
December 2016 Complete permanent shaft works at Coronation Park
December 2016 to August 2017 Commissioning and restoration

How are you making the tunnel?

A rock tunnel boring machine will be used for tunnel construction.

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Will there be any access holes or trenches on the surface while you are tunnelling?

There will be several 600mm diameter access holes created for venting air and grout, and concrete delivery during construction. The holes will be drilled and lined with a steel liner. The holes will be filled in after construction and the surface restored to its current landscape. Venting/grout holes will not be installed in driveways or near tree driplines or under power lines.

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What impact will tunnelling have on the properties above?

There should be no impact to homes along Third Line or Lakeshore Road.

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Are tours available?

Unfortunately due to the nature of this construction activity, tours of the shaft construction area and tunnel are not available to the general public for safety reasons.

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When the project is complete will there be any new structures above ground along the tunnel route?

There will be no above ground permanent features along Third Line or Lakeshore Road. There will be an air vent system installed by the existing pumping station in Coronation Park. The Town and public will have full use of Coronation Park after construction is complete.

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Will my driveway be obstructed at any time during the project?

Halton is not anticipating any obstructions to driveways during the installation of the air/grout holes and during delivery of grout and concrete. We anticipate that trucks may line up along the roadway but driveways should not be blocked.

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Will my yard or property be disturbed by any construction activities, including excavations, changes to landscaping, or parking or storage of construction equipment?

Halton does not anticipate any disruption to driveways or parking during construction. The location of air/grout holes may disrupt some landscaping but it should be minimal and all landscaping will be restored to its current condition.

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What will the near shore water quality be like after the project?

Currently the Mid Halton and Oakville Southwest wastewater treatment plants share a combined effluent outfall which outlets to Lake Ontario at the Coronation Park location approximately 750m offshore. Following completion of this project, the effluent from these two treatment plants will be separated. The Mid Halton Wastewater Treatment Plant will have a new, dedicated effluent outfall which will extend further offshore than the existing outfall.

During the Environmental Assessment for the project, several design alternatives were evaluated with input from the Ministry of the Environment and Climate Change to identify the preferred outfall location, length and diffuser design. The proposed new effluent outfall has been designed to have a positive impact on the near shore water quality to ensure all Provincial Water Quality Objectives are met.

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What testing is done to ensure the water quality of the lake is preserved?

Currently, Halton Region regularly samples effluent from the Mid Halton and Oakville Southwest wastewater treatment plants to ensure that effluent is within approved limits as identified in the Ministry of Environment and Climate Change Environmental Certificate of Approval (ECA) and Provincial Water Quality Objectives are met. The results of this testing must be reported to the Ministry of the Environment and Climate Change on a regular basis. Once the new effluent outfall is commissioned, a similar testing and reporting protocol will be in effect to ensure the continued safety of the water.

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When the project is completed, what testing will be carried out in the area that discharges treated water into Lake Ontario?

Halton currently samples the effluent from the Mid Halton Wastewater Treatment Plant and Oakville Southwest Wastewater Treatment Plant and reports the results to the Ministry of Environment and Climate Change (MOECC). Halton will continue to sample regularly and report to the MOECC as required by the Environmental Compliance Approval.

Halton also continuously samples and monitors the beach water of Lake Ontario for quality.

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Will the discharge pipe cause any algae or odour in the area?

No, the discharge pipe will be submerged under 30 metres of water and will disperse into the lake.

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Why is there a barge (flat-bottomed freight boat) out on the lake as part of this project?

The barge is 2km offshore to help with the installation of risers and diffusers for the water returning to Lake Ontario.

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How long will the barge be out on the lake?

It is anticipated that the barge will be out on the water until the end of September 2015. It will return in spring of 2017 to open the diffusers for the commissioning and use of the outfall when the project is complete.

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How can I learn more about this project?

For more information:

  • Visit halton.ca/construction. Go to Regional construction projects, select Oakville and then Third Line & Coronation Park - Mid Halton Outfall Pipe.
  • Contact Brenda Kingsmill, Project Manager, Halton Region:

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