West Vaughan Sewage Servicing Project

The West Vaughan Sewage Servicing Project will accommodate future growth sewage servicing demands and continue to provide sustainable wastewater servicing for surrounding communities.

map of project area

Tunnel

The work includes construction of the tunnel (phase one), trunk sewer and related shafts. The sewer will be approximately 11 kilometres long with a 3 metre internal diameter. The sewer conveyance tunnel in the City of Vaughan will run along Highway 27, Highway 7 and terminate at the York Region Humber Sewage Pumping Station off Steeles Avenue. The shafts and tunnel will convey sanitary flow from connections at Huntington Road and other local connections to the upgraded Humber Sewage Pumping Station.

The sewer alignment is divided into three segments: South, Central, and West. Tunnel boring machines (TBMs) will be used for excavation with an internal diameter of 3 metres and precast concrete segments for tunnel liners.

Scope

The tunnel (phase one) work contract will be preceded by the Humber Sewage Pumping Station advanced contract (Contract A) where a new pump station will be built and commissioned. Construction of the launch shaft (7L) will be part of Contract A scope handed over to the tunnel contractor to be used as the launching point for the South segment drive. The tunnel contractor is to supply two TBMs to execute the 3 metre tunnel (internal diameter) and the 250 millimetre thickness precast concrete segments (PCTL) necessary for tunnel lining.

Cost and Schedule

The overall capital cost of the tunnel (phase one) trunk sewer has been estimated at approximately $315 million.

The anticipated start date for construction is expected in Q1 2023 with a projected commissioning by Q1 2028 and completion by Q3 2028.

Request for Tender documents are planned to be released in Q3 2022.

Contract Key Features

  • Construction Start: Q1 2023

  • Commissioning: Q1 2028

  • 11.3 kilometre tunnel length

  • 3 metre internal diameter

  • 2 new tunnel boring machines (TBMs); 4 tunnel drives

  • 8 construction compounds

  • 3 launching shafts

  • 3 extraction shafts

  • 3 maintenance shafts

Shafts

In addition to the shaft (7L) constructed as part of the pumping station contract, seven shafts will be required for the sewer tunnel work. These shafts are to be constructed as part of the scope of the tunnel contract as follows:

  • 2 new launching shafts (2L, 5L)
  • 3 maintenance shafts (4MS, 5MS and 7MS) to be located between four suggested TBM drives for inspection and maintenance access
  • 3 extraction shafts (2L-reused for extraction, 3E and 6E)

The contractor will implement necessary means and methods to maintain dry excavation within all shafts without dewatering. The shafts range in depth from approximately 17 metres to 51 metres, with final internal diameters from 6 metres to 20 metres and will be lined with cast-in-place concrete for permanent structural support.

Geotechnical Overview

The site lies on the border of the physiographic region of Southern Ontario known as the Peel Plain and South Slope, delineated in the Physiography of Southern Ontario. The surficial soils of these physiographic regions are generally comprised of calcareous clay till with lacustrine clay and silt reworked by glaciers, with numerous scattered drumlins and deep valley cuts caused by flowing steams towards Lake Ontario.

The recent sand, silt, clay and uppermost till deposits in this area overlie and are interbedded with stratified deposits of sand, silt and clay. The area which contains zones of Peel Ponds is comprised of localized deposits of loose sand and silt and/or soft clay overlying this till sheet. The Peel Ponds represent relatively recent deposits formed in small glacial meltwater ponds scattered throughout the South Slope and Peel Plains and tend to be concentrated near river valleys.

The bedrock encountered down to the tunnel horizon comprises the Georgian Bay Formation, which is dominantly grey shale with frequent but thin limestone and siltstone interbeds. The bedrock surface exhibits topographic variation with bedrock valleys and hills occurring along the alignment.

 

View full size topographical maps (shown below).

Contractor Request for Pre-qualification (RFPQ)

A Request for Pre-Qualification (RFPQ) will be released at the end of Q1 2022 for contractors who wish to be pre-qualified as a general contractor to undertake the construction of the proposed works.

Interested contractors are encouraged to download the RFPQ when it becomes available from York Region’s Bids and Tenders website at no charge.

Contractor Information Session

A non-mandatory information session will be scheduled in 2022 with a detailed presentation/overview of the project. The session will be followed by a general project area site tour the same day. Details of the non-mandatory information session and site visit schedule will be included in the RFPQ document on the Region’s Bids and Tenders website.

Virtual Contractor Information Session

A non-mandatory presentation/overview of the project for prospective bidders unable to attend the information session will be held.

Details of the webinar will be included in the RFPQ document on the Region’s Bids and Tenders website.

For more information please contact:

Susan Hope
Supervisor Procurement Operations
Procurement Office
The Regional Municipality of York
1-877-464-9675 ext. 71695
@email (preferred method)