The Ewingsdale Tunnel in the Cape Byron area

This case study demonstrates design principle four from the Beyond the Pavement urban design guide: Fitting with the landform.

The Ewingsdale Tunnel in the Cape Byron area

The Pacific Highway Urban Design Framework requires projects to flow with the landscape creating a seamless fit with the topography. Few projects do this as well as at the Ewingsdale ridge where a major feature of this 17km section of new motorway is its passing through the St Helena ridgeline in a short tunnel to avoid a deep cutting scarring the landscape (1).

The tunnel retains as much of the hillside topography as possible extending under the natural ridgeline, which forms a threshold between the elevated plateau and the coastal hinterland and Byron Bay, The hillside has been re-created to fill the original landform, and the portals and approaches have been designed to integrate the structure with the natural landform (2).

North of the tunnel a clear noise wall (3) allows views of Cape Byron and the Pacific Ocean. South of the tunnel the highway takes a flowing alignment through the topography and agricultural lands. It has a series of simple refined bridges and is characterised by rounded cuttings and native planting. Its fit into the valley and undulating setting, with a rich continuous landscape and integration with farmlands, creates a memorable visual experience.

The white tunnel portal collars contrast and highlight the landscape and landform around. They divert storm water and provide a maintenance safety parapet. The landform wrapped around the portals and laid back to natural grades is a long term safe earthworks solution which avoids walls, their maintenance and graffiti.

The view from the tunnel portal heading north frames the view of Cape Byron.

The tunnel control centre was set into the ground below the ridge line ensuring open views to Cape Byron.