Lynn Valley trunk sewer upgrade

 

We are replacing the trunk sewer on Mountain Highway between East 24th Street and East 18th Street.

Built in 1964, the aging sewer has reached the end of its service life. The new sewer will be constructed with larger pipe to increase capacity to meet current and future demands. This significant piece of infrastructure is responsible for carrying sanitary waste for approximately 21,000 area residents.

Construction is scheduled to begin in fall 2022 and will take approximately one year to complete.  

Crews will use micro-tunnel construction to excavate an underground tunnel without disturbing the road above. This method will have less impact on traffic than traditional excavation methods. See the 'micro-tunnelling' tab below for more.

Progress report 

We will provide regular updates on the progress of the underground tunnelling and pipe laying for duration of this project.

A graphic of a road with vehicles on the surface of a road demonstrating progress on the underground tunnel between East 18th Street and East 24th Street. Currently the progress is at 5%.

Current status: Boring is scheduled to start in mid-March.

News & updates

March 7, 2023 — Completion of launch shaft at East 20th

The launch shaft construction will soon be complete, and we anticipate the delivery of the tunnel boring machine in the coming weeks. Shortly after, tunnel excavation work will begin underground along Mountain Highway, starting in the southbound direction toward E 18th Street. 

January 23, 2023 — Construction begins

Construction of the launch shaft for the micro-tunneling boring machine has started at the intersection of Mountain Highway and 20th Street. Here, a large circular shaft will be excavated to a depth of 10 metres.

Over the next month, once the shaft is completed and the boring equipment is in place, tunneling underneath Mountain Highway will first begin in a southward direction, towards 18th Street, where an exit shaft will be constructed. The intersection at 18th will remain open, however traffic will be one lane in each direction. In the coming weeks, a facility will be installed on the west side of Mountain Highway to separate the rocks, soil, and water left behind by the tunneling process. 

Yellow excavators begin digging a hole for a trunk sewer project.

December 19, 2022 — East 20th closure extended due to weather

Winter weather conditions are preventing the patch and repave of the intersection following watermain relocation. Unfortunately, this means that the closure of East 20th Street at Mountain Highway will not be able to reopen over the Christmas break, as previously planned. The closure will now remain in place for the duration of the project. 

December 5, 2022 — Work rescheduled

Watermain relocation work and related street closures that were postponed this week have been rescheduled to start Monday, December 12 and finish by December 21, 2022. This work requires the closure of East 20th Street at Mountain Highway. In addition, traffic on Mountain Highway will be reduced to one lane northbound at East 20th.

After the watermain work is complete, East 20th Street will reopen for the Christmas break on December 22 and close again on January 9, 2023 for the remainder of the project. 

December 2, 2022 — Closure postponed

The watermain work and related closures that were scheduled to start on Monday, December 5 have been postponed. We will provide an update as soon as this work is rescheduled. 

November 29, 2022 — Closure of East 20th Street

Starting Monday, December 5, East 20th Street at Mountain Highway will be closed to all traffic for the duration of the Lynn Valley trunk sewer project through summer 2023.

Also starting Monday, traffic on Mountain Highway at East 20th St. will be reduced to one lane northbound for approximately two weeks to relocate a watermain in preparation for the micro-tunnelling. One lane will remain for southbound traffic. Following this phase of work, all traffic lanes will be restored temporarily until January 2023, when the micro-tunnelling work will begin.

One lane in each direction will be maintained on Mountain Highway for the duration of the project.

October 27, 2022 — Site preparations 

The contractor will be setting up on site starting next week, and beginning preparations for the micro-tunnelling work to follow. 

Map of construction area

Construction area

This map shows the sewer trunk construction area along Mountain Highway. One lane of traffic will be maintained in each direction on Mountain Highway.

East 20th Street will be closed at Mountain Highway to all vehicle traffic for the duration of the project, starting December 5, 2022. Starting later this spring, East 24th Street will also be closed to traffic at Mountain Highway until the project is completed in fall 2023. Pedestrian access will be maintained at all times. For your safety, please obey all traffic signage and flaggers in the area. 

A map showing construction areas and road closures for the Lynn Valley Trunk Sewer Project, between E 24th St and E 20th St. Later this spring E 24th closed to vehicles at Mountain Hwy. E 20th closed to vehicles at Mountain Hwy.

Construction timeline

Southbound boring begins Spring 2023

We expect tunnel boring work will begin underground along Mountain Highway in late March or early April, starting first in the southbound direction. As the tunnel works its way towards its destination at East 18th Street, sections of the new sewer pipe will be installed along the way. Construction will begin shortly at East 18th Street to build the reception shaft and manholes where we will ultimately connect the new pipe sections to the existing sewer.

Heading north 

Once the new sewer between East 20th Street and East 18th Street is installed, the tunnel boring machine will be returned to the shaft at East 20th Street and relaunched in the northbound direction to East 24th Street. Construction of the reception shaft at East 24th Street will begin later this spring and will require the closure of East 24th Street at Mountain Highway for the remainder of the project. 

*Timeline at glance:

  • March – Tunnel equipment installation and setup
  • March to April – Tunnelling from East 20th St to East 18th St
  • Early April – Set up construction at East 18th St
  • May to June – Tunneling from East 20th St to East 24th St
  • Mid-May – Set up construction at East 24th St

*Please note, this timeline is subject to change. 

Micro-tunnelling: what to expect

Micro-tunnelling: A less disruptive method of construction

Traditional construction methods would require trenching the entire stretch of Mountain Highway to complete this project.

Instead, we will use micro-tunnelling methods that utilize a boring machine to excavate an underground tunnel. This method will only require three excavations along the entire sewer route: one for the entrance at East 20th Street, and two exits, at East 18th Street and East 24th Street. At the exit shafts, traditional excavation methods will be used to connect the new trunk sewer to existing sanitary drainage.  

Recent projects completed by Metro Vancouver have shown micro-tunnelling to be less disruptive and a less expensive way to replace large-diameter sewer mains compared to traditional excavation methods. 

Traffic impacts

While the micro-tunnel construction method of sewer replacement significantly minimizes impacts on traffic, there will be some disruptions and delays. We expect to maintain a minimum of one lane in each direction at all times through all affected areas on Mountain Highway, with the exception of vehicle access to and from East 20th Street via Mountain Highway, which will be closed for the duration of construction. The intersection at East 24th will also require full closure for a period of time, likely in spring 2023. 

Safe pedestrian routes will be maintained at all times.

Noise impacts

Micro-tunnelling requires the temporary set up of a separation plant close to the work site to sort the materials (dirt, rocks, etc.) pulled from the tunnel. This separation plant will be located in the BC Hydro right-of-way, off Mountain Highway, and is expected to produce noise and vibration.

Depending on ground conditions, 24-hour work may be required during tunnelling work. 

We will make every effort to manage these impacts where possible by implementing noise and vibration reduction best practices and conducting noise monitoring and measurement throughout the project.

Background

The trunk sewer section between East 24th and East 18th Street on Mountain Highway is nearing the end of its expected service life and is undersized to meet additional demands. 

With several Lynn Valley Town Centre projects nearing completion and occupancy, demand on the existing sewer trunk is expected to increase. In addition, during wet weather, this section of sewer is known to run above capacity as rainwater leaks into defects of the aging infrastructure. Due to climate change, the increasing frequency of significant rainfall events will further the strain. 

The new sewer with upsized pipe will be capable of handling increased capacity demand now and in the future and is expected to have an 80- to 100-year lifespan. 

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