Outfall Pipe Assembly and Installation | Town of The Blue Mountains, ON

Dredging Progress

September 11, 2026 - Approximately 288 metres of the trench has been excavated to full depth, and an additional 40 metres has been excavated to partial depth. The final 100 metres of the trenched portion requires minimal digging. No dredging was completed on Thursday, September 10 due to weather conditions.

On this page:
1. Project Updates
2. Outfall Installation Details
3. Lora Bay Park Site Map
4. Staff Reports & Council Decisions
5. Public Consultation
6. Frequently Asked Questions

The Town is upgrading the Thornbury Wastewater Treatment Plant Outfall Pipe to allow the plant to meet its full capacity. This outfall will be installed off the north end of the Grey Street road allowance, and run 1.5 km into Georgian Bay. The pipes will be assembled in 200m lengths on the shore, and then floated until final assembly can be completed.

In 2024, Town Staff, along with the Town’s Consultant, Arcadis, did a wide-ranging search of potential staging sites for the outfall pipe. The sites were evaluated based on accessibility, space for storage, assembling and construction equipment/facilities, water depth, protected waters and site security. Through the evaluation process, Lora Bay Park was deemed the only suitable site. Although the public use of the park would be interrupted for the summer, using Town lands to construct the offshore pipe would eliminate the costs associated with a lease agreement of a private landowner, therefore reducing the overall cost of construction.

The shoreline of Georgian Bay has a restricted activity window for the protection of spawning fish that extends between September and July. This window provides approximately 2.5 months to conduct any work in Georgian Bay. Pre-construction preparation will be conducted before the window opens to ensure that work on the shoreline can be completed on time. Public access to Lora Bay Park will be prohibited during the pre-construction and construction window.

Why Now?
The Town needs to upgrade the Thornbury Wastewater Treatment Plant Outfall Pipe to allow the plant to meet its full capacity.

Project Updates

Construction Updates

September 11, 2026 - Implementation of night-shift dredging operations and extension of in-water work permit

The project contractor has recently implemented a three-barge operation to increase the rate of offshore trenching and dredging work. Despite these additional resources, challenging lakebed conditions, water conditions and machinery downtime continue to affect daily production rates.

To help advance the work, the contractor will be introducing night-shift dredging operations beginning Friday, September 11. The night shift will operate from 7:00 p.m. to 7:00 a.m. using the primary barge and excavator only. This approach will allow offshore trenching activities to operate on a near-continuous basis, subject to weather conditions and established safety requirements. Overnight work will begin approximately 290 metres offshore and will progress into deeper water over time. Work closer to the shoreline will be completed during daytime hours only. All work will continue to be carried out in accordance with applicable approvals and environmental protection measures.

The public may notice additional activity and lighting associated with the offshore work during overnight hours. The Town recognizes this may affect nearby residents and lake users and appreciates the community’s patience as the project team works to complete this critical infrastructure project.

The Town has also received approval from the Department of Fisheries and Oceans, Ministry of Natural Resources and Grey Sauble Conservation Authority to extend the in-water work permit until Wednesday, October 14, 2026.

September 4, 2026 - Dredging update and mobilization of second excavator
The Town's contractor has reported that they have completed 28 metres of dredging in the first four days of this week. A second barge and excavator is being delivered to the Grey Street road allowance, and is expected to be operational shortly. The second excavator will assist with the remaining dredging and the completion of backfilling following the pipe installation to ensure that production targets are met. Work will continue throughout the long weekend in accordance with the hours presented to and approved by Council for in-water and onshore work.
A new section has been added to the top of the project page to highlight dredging progress. This content will be updated on a daily basis, Monday to Friday, and a summary will be included in the weekly progress email.
August 28, 2026 - Weekend work plan for August 29-30
The Town's contractor has completed work on the valve chamber located in the Grey Street road allowance between Bay Street East and the shoreline. In line with the Staff Report presented on Tuesday, August 25, the contractor's in-water work hours will extend as late as 7 p.m. on Saturday, with the addition of 7 a.m. to 1 p.m. on Sunday. The weekend work plan calls for ballast preparation work at Lora Bay Park and the continuation of in-water dredging work off the shoreline of the Grey Street road allowance.
August 21, 2026 - Weekend work plan and lookahead schedule
The contractor again expects to work extended hours from 1 p.m. to 5 p.m. this Saturday to continue in-water dredging, weather and water conditions permitting. They also expect to be performing general site maintenance activities at Lora Bay Park. Looking ahead to next week, the primary areas of focus will be the continuation of dredging, with some material deliveries to Lora Bay Park and the Grey Street site expected later in the week.
August 14, 2026 - Weekend work plan and lookahead schedule
The contractor expects to work extended hours from 1 p.m. to 5 p.m. this Saturday to continue in-water dredging, weather and water conditions permitting. They also expect to be performing general site maintenance activities at Lora Bay Park. Looking ahead to next week, the primary areas of focus will be the continuation of dredging and the installation of concrete ballast weights.
August 12, 2026 - Transition to barge dredging underway
The Town's contractor has reached the stage of the dredging where they have begun to transition to excavating from a barge. A temporary in-water berm has been constructed from clear stone to serve as a work platform for the dredging up to this point. This berm has allowed the machinery to stay out of the water while completing the shallow dredging, minimizing contamination from grease and other foreign substances that might be present on the excavator. The contractor is currently completing the work associated with the temporary berm, and it is anticipated that the dredging operation will fully transition to the barge within the next week.
The clear stone used to construct the berm will be removed following completion of this portion of the work, and the recovered stone will be reused as part of the required pipe bedding. Additional material will be placed on top of the bedding to prevent it from washing up onto the shore. Following installation of the new outfall, the shoreline and work area will be restored in accordance with the project requirements.
August 7, 2026 - Dredging resumes along with stockpiling of clear stone
The Town's contractor has completed installation of the modified turbidity curtain layout, and has resumed dredging operations. They have also begun stockpiling clear stone and are using it to build a temporary in-water berm. The clear stone will be used for bedding and backfilling around the buried section of the new outfall pipe when it's installed. Clear stone deliveries are expected to continue until the beginning of September at both Lora Bay Park and the Grey Street North site.
The contractor expects to work extended hours from 1 p.m. to 5 p.m. this Saturday with site maintenance being completed at Lora Bay Park, and dredging continuing at the Grey Street North site, pending water and weather conditions.
July 31, 2026 - Limited weekend work plan
In accordance with Council's direction, the Town's contractor will be limiting working hours this weekend to those allowed by the Town's Noise By-law. They plan to work 8:00 a.m. to 1:00 p.m. on Saturday, August 1, and a full day 7:00 a.m. to 7:00 p.m. on Monday, August 4. Planned work activities for Saturday include pipe fusing and site maintenance at Lora Bay Park, and turbidity curtain installation off the Grey Street road allowance. In-water dredging is currently expected to resume on Monday, August 4, weather and water conditions permitting.
July 30, 2026 - Water sampling results and pipe sinking in Lora Bay
The Town has received analysis results of water samples taken on Monday, July 20 from two locations at the Grey Street North installation site. The analysis measures total suspended solids which is a standard gauge of turbidity and water quality. Measured quantities were 15 mg/L north of the dredging zone and 35 mg/L south of the dredging zone. The Town is working with an independent Environmental Consultant to provide the review and feedback of the analysis.
View Results
At Lora Bay Park, Deepsix has partially filled the staged pipe with water to position it just below the water surface. This is a planned measure designed to reduce the effects of wave action by allowing wave energy to pass over the pipe rather than be resisted by it. Additional visual markers and buoys are being installed to clearly identify the pipe's location for residents and recreational watercraft operating in the area.
July 30, 2026 - Approval of amended construction plan
The amended construction plan formulated by the Town's contractor has been reviewed and approved by the Town’s engineering consultant, the Ministry of Natural Resources, the Department of Fisheries and Oceans, and local Conservation Authorities.
The turbidity curtain will be redeployed in a modified configuration to support completion of the remaining dredging work. The revised configuration will place remaining, usable curtain sections along both sides of the dredging corridor. The offshore end will remain open to reduce pressure from wind and waves, improving the system’s resilience during changing lake conditions. The contractor plans to begin reinstalling the turbidity curtain system and resuming dredging as early as Thursday, July 30, pending suitable weather and water conditions.
Maintaining environmental and public health remains paramount in the amended plan. Continuous turbidity monitoring will remain in place during dredging. If the monitoring system detects turbidity levels in exceedance of approved thresholds, response actions will be implemented, up to and including temporary suspension of dredging. The Town has also engaged a third-party consultant to complete water quality testing periodically along the shoreline outside the dredging corridor.
More details can be found in the full media release linked below.
View Media Release
July 24, 2026 - Update on next steps and weekend work plan
Following the weather incident that occurred on the weekend of July 18, the Town continues to work with its contractors and engineering consultant to formulate a plan to resume installation of the new outfall without impacting the overall project deadline. The Town has been in contact with the Ministry of Natural Resources, Department of Fisheries and Oceans, Conservation Authorities and other agencies that will need to review and approve the amended plan. Details will be shared once the plan has been finalized and approved at all levels.
The contractor expects to work extended hours from 1 p.m. to 5 p.m. this Saturday to continue pipe fusing at Lora Bay Park and to perform general maintenance at the Grey Street North site. Water quality testing was completed at the Grey Street North site earlier this week. Results will be shared to the project page when available.
July 17, 2026 - Extended Saturday hours for shoreline dredging
The contractor expects to work extended hours from 1 p.m. to 5 p.m. this Saturday to continue shoreline dredging, weather and water conditions permitting. They currently have approximately 70 metres of the dredging completed. Pipe fusing is also expected to restart at Lora Bay Park next week following delivery of materials.
July 10, 2026 - Turbidity monitoring alert
Earlier today, the Town's contractor was alerted of excess turbidity in the water in the area around the dredging site. They inspected the turbidity curtains and identified a minor failure which was immediately secured. The turbidity curtain installation includes a monitoring system which will continue to alert staff of any future issues.
July 9, 2026 - Extended Saturday hours for shoreline dredging
The contractor expects to work extended hours from 1 p.m. to 5 p.m. this weekend to continue shoreline dredging from the Grey Street North road allowance, weather and water conditions permitting. In accordance with Council's direction, no work will be conducted on Sunday.
July 8, 2026 - Shoreline dredging to begin this week
Dredging for the installation of the offshore section of the new outfall pipe at the Grey Street North road allowance is expected to begin on Thursday, July 9. Turbidity curtains have been installed in the Bay to prevent sediment from drifting in the currents once dredging begins. A subcontractor was on site today completing fish rescues from within the curtained area. At Lora Bay Park, pipe fusing activity will temporarily pause as the contractor waits on delivery of additional materials.
July 2, 2026 - In-water Work Permit window opens and weekend work at Lora Bay Park
The Town's permitted window for in-water work has opened as of July 1, and the marine work contractor has begun placing anchors and equipment in the water off the north end of the Grey Street road allowance. The contractor has also informed the Town that they will be working extended hours from 1 p.m. to 5 p.m. at Lora Bay Park to complete pipe fusing on July 4, July 11 and July 18. No work will be conducted on Sundays over these weekends.
June 1, 2026 - Contractor mobilizing to Lora Bay Park
Clearway Construction has begun mobilizing to Lora Bay Park to start the assembly of the new outfall pipe for the Thornbury Wastewater Treatment Plant. They will be working this week to install security fencing and place equipment.

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Other Project Updates

August 18, 2026 - Upcoming Staff Report regarding working hours

A Staff Report is scheduled to be presented to Committee of the Whole on Tuesday, August 25. Details can be found in the Staff Reports section of this page.

View Staff Reports

The Town has scheduled a Community Information Sessions to provide an overview and update on the installation of the new treated effluent outfall pipe for the Thornbury Wastewater Treatment Plant. The Town’s engineering consultant, Arcadis, will be giving a presentation outlining the outfall installation process and the planned site restoration activities. Time will be held for a Question & Answer Session at the end of the meeting. The meeting will be recorded and posted to the project page for anyone unable to attend in person. If you are unable to attend the meeting in person, but have questions that you would like asked on your behalf during the Q&A, please email them to communications@thebluemountains.ca.
Date: Friday, August 28, 2026
Time: 1-2 p.m.
Location: Town Hall, 32 Mill Street, Thornbury
View Notice
The Town has awarded the construction contract for the assembly and installation of the offshore portion of the new outfall to Clearway Construction Inc. Unfortunately, the Town faced unexpected delays in the pre-qualification and tendering process. These delays made it impossible to complete the in-water work within the timeframe allotted for 2025 by the Ministry of Natural Resources. The Town plans to proceed with the work in 2026.
The construction tender for the assembly and installation of the new Thornbury Wastewater Treatment Plant outfall pipe is now open on the Town's Bids and Tenders website. Three contractors were identified through the pre-qualification process, and final bids will be accepted until Thursday, July 3, 2025. Once a contractor is retained, they will provide a more detailed schedule for the work and the Town will send out a construction newsletter. Ongoing updates will be posted to the project web page as information becomes available.

Outfall Installation Details

A new outfall is to be constructed to accommodate the approved increased capacity to the Thornbury Wastewater Treatment Plant. The new outfall alignment extends from the Treatment Plant to the shoreline of Georgian Bay, following within the existing Grey Street road allowance. The outfall alignment includes the crossings of King Street East (MTO Highway 26 at Grey Street) and at Bay Street.

The outfall extends 1500 m to the north from the shoreline into Georgian Bay. Approximately the first 600 m of the outfall pipe from the shoreline will be dredged, and the remaining segment will lay on the lakebed in the deeper water. Due to fisheries windows, the marine portion of the outfall will need to begin no earlier than July 1, and be completed no later than September 30.

Turbidity curtains have been instilled to minimize the spread of suspended sediment. Due to the nature of the lakebed (hard clay) and the fact that the curtain does allow for some water movement, discolouration of the water on the outside of the curtain cannot be avoided. The contractor has real-time turbidity monitoring buoys set up on the east and west side of the dredging site. As the dredging progresses offshore into the sand and gravel lakebed, turbidity is expected to be reduced.

Map showing general location of outfall installation off the shoreline of Georgian Bay — Approximate extents of in-water construction work

Lora Bay Park Site Map

Staff Reports & Council Decisions

Staff Report OPS.26.047 was presented to Committee of the Whole on Tuesday, August 25. The report is being presented to inform Council that the contractor will be working extended hours offshore, beyond the Town's municipal boundary. The Town’s Noise By-law cannot regulate offshore activities solely because noise generated by those activities may be audible from Thornbury. The contractor has previously been approved to work extended hours on Saturdays from 1:00 p.m. to 5:00 p.m. Despite this extension, there remains a risk that the work may not be able to be completed within the permitted timeframe.
The contractor has submitted a request for additional working hours including Monday to Friday from 7:00 a.m. to 9:00 p.m., Saturdays from 7:00 a.m. to 7:00 p.m. and Sundays from 7:00 a.m. to 1:00 p.m. The intent is to use these additional hours primarily for less disruptive construction activities. The extended work period would be dedicated to offshore operations occurring a considerable distance from the shoreline, minimizing potential impacts to nearby residents.
Presentation of the report begins at the 4:21:15 mark of the meeting recording.
View Meeting Recording
Staff Report OPS.26.041 was presented at a Special Meeting of Council on Wednesday, July 8. The report is an update to a previous request of Council to grant relief from the Town's Noise By-law to complete work on the assembly and installation of the new treated effluent outfall pipe for the Thornbury Wastewater Treatment Plant.
Council previously approved relief from the By-Law for a total of three weekends, excluding long weekends, during the summer construction period. Since that approval, the contractor has requested that the Town reconsider the relief granted. The Contractor has advised that they would prefer to have the flexibility to work full days on Saturdays as needed, from 8:00 a.m. to 5:00 p.m. This would improve construction efficiency and help maintain the project schedule. While the Noise By-Law currently permits construction only until 1:00 p.m. on Saturdays, this report seeks Council's approval to extend the permitted construction hours from 1:00 p.m. to 5:00 p.m. on Saturdays for the duration of the project. In turn, the contractor could avoid work on Sundays for the duration of the project.
Council heard the report and voted in favour of the following motion:
THAT Council receive Staff Report OPS.26.041, entitled “Outfall Noise By-Law Relief”;
AND THAT Council grant relief from Noise By-Law 2002-09 from July 11, 2026, to September 30th, 2026, for Saturdays from 1:00 p.m. to 5:00 p.m., excluding long weekends, for work related to the construction of the Effluent Outfall;
AND THAT Council direct Staff to continue to communicate real time updates with Residents on the work being completed;
AND THAT approval of this request be subject to construction works not occurring on Sundays.
Presentation of the report begins at the 12:40 mark of the meeting recording.
View Meeting Recording
Staff Report OPS.26.024 was presented to Committee of the Whole on Tuesday, April 28. The report provides an update on the status of the Outfall Assembly and Installation project, and requests that Council grant relief from the Town's Noise By-law to allow for work to be completed on weekends as required to remain within the in-water construction window allowed by the MNRF. Committee heard the report and passed a motion that will allow for work to be completed on a maximum of three weekends over the exemption period between May 15 and September 31. The Town will be utilizing the project email lists for this page and the Bay Street East Reconstruction project to notify the public of the specific weekends when additional work will be occurring.
Presentation of the report begins at the 1:42:40 mark of the meeting recording. The Committee motions were adopted by Council at their meeting on Monday, May 11.
View Meeting Recording
Staff Report OPS.25.015 was presented to Committee of the Whole on Tuesday, March 18. The report provided an update on the staging site for the construction of the new Thornbury Wastewater Treatment Plant Outfall pipe. Given multiple factors, staff have identified Lora Bay Park as the location for the assembly of the new outfall, and Council has approved this location. The outfall will be assembled at Lora Bay Park in segments, and then towed across Georgian Bay for installation north of the Grey Street road allowance in Thornbury. The report includes a communications plan, along with a set of Frequently Asked Questions covering how Lora Bay Park was selected and what the impacts to the public will be. Committee voted in favour of the staff recommendations, and this direction was adopted by Council at their meeting on Monday, March 24.
Presentation of the report begins at the 1:24:10 mark of the Committee meeting recording.
View Meeting Recording
Contractors are expected to be on site at Lora Bay Park on Tuesday, March 18 to begin topographical surveying. This information will be used to assist with the development of a site plan for the future construction work.
Staff Report CSOPS.22.025 was presented at a Special Committee of the Whole meeting on May 3, 2022. The report provided an update on the Thornbury Wastewater Treatment Plant Expansion project, and requested Council approval for an increase to the project budget and for the design of the new outfall line to be awarded to IBI Group. Committee of the Whole voted 4-2 in favour of the recommendations. This was adopted by Council at their meeting on May 24, 2022.
Committee discussion of the Staff Report begins at the 4:07:00 mark of the meeting recording.
View Meeting Recording

Public Consultation

Community Information Session - August 28, 2026

A Community Information Session was held on Friday, August 28, 2026 at Town Hall to provide an overview and update on the installation of the new treated eflluent outfall pipe for the Thornbury Wastewater Treatment Plant. The Town’s engineering consultant, Arcadis, gave a presentation outlining the outfall installation process and the planned site restoration activities. A Question & Answer Session was conducted at the end of the meeting.

View Meeting Recording

View Presentation Deck

View Notice

Lora Bay Park Restoration

Consistent with Council direction, a Staff Report is expected to be brought forward later this year to consider an approach to park revitalization. This could lead to an opportunity to make improvements as restoration works occur, or folding engagement and visioning through the development of the Parks, Open Spaces and Trails Master Plan that will be commencing this year. To be notified of any future public consultation opportunities regarding the project, please subscribe to the project email list.

Frequently Asked Questions

The outfall is part of the greater Thornbury Wastewater Treatment Plant Expansion. The expansion is replacing end-of-life equipment and ensuring that the plant is capable of providing reliable service in line with the forecasted growth of the community.
The current outfall has a maximum diameter of 406mm, which does not meet the capacity requirements for the Thornbury Wastewater Treatment Plant following its expansion. A minimum piping size of 500mm will be required. The new outfall also provides an opportunity to remove the current outfall from the Beaver River, a cold-water fishery, to a more suitable location further offshore, and in deeper water.
No, there will be no permanent installation at Lora Bay Park. The new effluent outfall will extend from the Thornbury Wastewater Treatment Plant north on Grey Street, to the shoreline located on the unopened section of Grey Street, then proceed an additional 1.5 km offshore into Georgian Bay. Lora Bay Park will only be used as a temporary staging site for the construction of the pipe required for the outfall.
Any work in Georgian Bay must be completed between July 1 and September 30. The shoreline has a restricted activity window for the protection of spawning fish. Pre-construction preparation will be conducted before July 1 to ensure that work on the shoreline can be completed on time. Additional work may be conducted upon completion of the outfall for park revitalization. Town staff plan to present a report to Council asking for a noise by-law exemption to allow for construction to take place seven days a week.