The tunnel’s legacy will be permanent damage to the environment at its entrance and exit points.
At its entrance point, near the start of the Routeburn Track in Mount Aspiring National Park, there is native forest, rare birds, such as mohua, and bats. At its exit point, the remote and magical Hollyford valley in Fiordland National Park, there is a lush forest alive with kaka parrots and kiwis alongside the rushing Hollyford river.
These two areas will be transformed into transport hubs with noisy and polluting emissions from a steady stream of coaches, and an increase in air traffic at a larger air strip in the Hollyford Valley. On-going maintenance of such a lengthy tunnel and its road access and facilities will add to the disruption.
The permanent and intrinsic changes to the character of these special places will be immense.