Reflections on a Flawed Planning Process for the Western Harbour Tunnel, Sydney

The paper is based on three report submissions made by the author to the NSW State Government Parliamentary Inquiry in 2021 into the Sydney Western Harbour Tunnel (WHT) and Beaches Link Tunnel (BLT) URL (Inquiry into impact of the Western Harbour Tunnel and Beaches Link–Sub 437 (2021) [1]; Inquiry into impact of the Western Harbour Tunnel and Beaches Link–Sub 437a (2021) [2]; Inquiry into impact of the Western Harbour Tunnel and Beaches Link–Sub 437b (2021) [3]). The WHT includes twin 16-m diameter TBM bored tunnels under Sydney Harbour as opposed to the original immersed tube proposal. The BLT was politically pushed, had initially been delayed but has now recently been cancelled with the change in state government in 2023. No Business Case for the BLT bored tunnel was publicly available. Major construction works are currently well advanced in and adjacent to the Warringah Expressway in North Sydney. The author’s submission proposed an extension of the WHT to go under North Sydney and beyond Chatswood (extending the WHT tunnel by at least 5km north, following the Pacific Highway corridor) and for a new 7km long east–west tunnel from the Roseville Bridge, Forestville to Macquarie Park passing under Chatswood, to replace the BLT. As part of this proposal a major underground interchange, conceptually similar, but less complex than the Westconnex Rozelle Interchange on the south side of the harbour, would be constructed under Chatswood. It is acknowledged that the financial viability of Westconnex depends on the completion of the WHT. Some concept images of the proposals are included together with the advantages over the current WHT alignment and the now cancelled BLT project. Other planning issues include a lack of redundancy in the road network leading to accident-related significant traffic delays, ventilation stack air pollution issues, community impacts, construction programmes and costs.