Sydney Western Harbour link procurement 03 Sep 2020

Fig 1. New Western Harbour and Beaches Link western bypass route

A second highway crossing of Sydney Harbour, to the west of the famous bridge and its existing capacity adding immersed tube crossing, is presented to the industry for expressions for a potential development partner to assist with procurement and delivery. The crossing is part of the wider Northern Beaches extension which is proposed to be a new tunnel from the northern beaches of Sydney, under Middle Harbour and connecting to Gore Hill Freeway and the Warringah Freeway (Fig 1). Transport for NSW expects to have more details on the Beaches Link project later in 2020 as part of the project’s environmental impact statement.

Unlike other highway projects in Sydney that have or are being delivered by a toll road operator, the Western Harbour crossing and its Northern Beaches Link are New South Wales State Government led projects. After engagement with industry, the NSW Government decided on a State-led procurement and delivery process and announced that through the expressions of interest, “we will be seeking to leverage private sector expertise such as innovative ideas and approaches to procurement and delivery”.

The Western Harbour link is proposed by NSW Transport in its reference design as an immersed tube crossing with mined tunnels at the landfalls (Fig 2). To the south, the underground harbour crossing will link to the underground Rozelle interchange and WestConnex highway routes and M6 underground Stage 1 alignment. To the north there will be a connection to the North Beaches extension and its tunnel crossing of Middle Harbour and also to an upgrade of the Warringah Freeway that links to the Harbour Bridge and Tunnel crossing (Fig 3).

The Warringah Freeway is one of the busiest roads of the city and its upgrade is designed by NSW Transport to increase safety for motorists and deliver better active transport links along the 4km upgrade stretch, and provide seamless connections to the Western Harbour Tunnel and Beaches Link. Procurement of the 4km Warringah Freeway upgrade is a separate call for expressions of interest process with NSW Transport.

The current call for expressions of interest for the Western Harbour project stated that “the potential involvement of a development partner will focus on procurement and delivery structures and not the financing of the project. Project costs will be finalised when construction contracts have been awarded.”

Warringah Freeway leading from north to the Harbour Bridge and Tunnel crossing, one of the busiest traffic routes in Sydney

Vertical alignments of existing and planned highway tunnels in Sydney

In creating a western bypass of the Sydney city centre, the Western Harbour Tunnel is designated as a nationally significant project to transform the way motorists move around the city and deliver faster and more reliable journeys under the harbour. NSW Transport in an email stated that: “In presenting their delivery partner proposals, tenderers will be able to propose their preferred tunnelling approach, ensuring the work delivers benefits including value for money and programme, performance and environmental outcomes – in construction and operation.”

Preliminary planning for a western crossing of Sydney Harbour began in 2015 with an initial design completed in March 2017 and the application for status of State Significant Infrastructure submitted in November 2017. Community engagement progressed from July to December 2018 and the project is currently completing its environmental impact assessments ahead of seeking planning approval. An indicative construction timeline of about six years, starting in 2021, has a potential opening date in 2026 or 2027.

Ahead of that, Sydney is:

• Preparing to open its NorthConnex underground highway;
• Has opened two parts of the underground WestConnex highway – the M4 and M5/M8 sections, and is progressing the WestConnex M4-M5 underground link and underground Rozelle interchange;
• Is evaluating proposals for the M6 Stage 1 underground highway project for award of a contract in early 2021 where TBMs may be the excavation method selected as opposed to the preference to date for roadheader excavation; and
• Is moving ahead with the Beaches Link highway with its underground crossing of Middle Harbour.

These projects add to existing underground roadways in Sydney including the existing Harbour immersed tube crossing, the Lane Cove project completed in the early 2000s and the Eastern Distributor double deck highway completed in the late 1990s.

They also add to the many kilometres of underground metro and rail projects completed in recent years and the many currently in planning.