For major road development projects, the big ideas that shape our overall approach to sustainability can be challenging to implement at a project level.

The duplication of the Hume Highway in south western NSW from Woomargama to Table Top shows how sustainability can be incorporated into a major road infrastructure project. Key considerations included traffic and transport efficiency, biodiversity, heritage, water management, community impacts and long-term and cumulative impacts.

To deliver the project successfully, the NSW Roads and Traffic Authority (RTA) decided to use an alliance – Hume Highway Southern Alliance – comprising of the RTA, Abigroup and Sinclair Knight Merz (SKM).

A sustainability workshop early in the project identified outcomes and objectives that would leave a legacy to the community, improve the sustainability of delivery methods for the project, and involved RTA personnel outside the Alliance in the development of the project, as well as other key stakeholders.

Due to the project's large scale, significant volumes of water are required. Preliminary hydrological investigations undertaken as part of the environmental assessment indicated there was a severe shortage of reliable water available in close proximity to the project.

Norske Skog Paper Mill (approximately 10 km south west of the project) was identified in this analysis as having a significant surplus of treated effluent and cooling water used in its paper milling process.

Working in conjunction with Norske Skog, the Hume Southern Alliance connected a pipeline from the irrigation system to the project alignment, transferring water to a series of interlinked storage dams. By using Norske Skog's existing pumps and pressure within the irrigation system, minimal energy is required to transfer water to the construction site.

The recycled water from the Norske Skog facility is providing approximately 50 per cent of construction water, significantly reducing the reliance on Lake Hume. The partnership with Norske Skog has also extended beyond the use of wastewater, with the use of bio solid materials.

These materials are a byproduct of the paper milling process. This paper mulch-like product is being used during revegetation and for erosion control.

Prior to construction, the Mullengandra tip was located under the new road alignment and contained burnt waste material and putrescible wastes that needed to be addressed.

The solution adopted included sorting material that could be recovered and recycled including metals and tyres, excavating and sieving the waste material to separate ash and soil for re-use in earthworks, with any remaining putrescible material then removed to the Albury landfill tip.

The outcome has eliminated the ongoing liability of a waste cell for the RTA, with an overall benefit to the local environment and the reduction of potential risks to the local surface and groundwater reserves.

There has been very effective collaboration between the environmental and design teams, along with the RTA environmental specialists to maximise the retention of Box Gum Woodland and minimise disturbance of heritage sites through alignment and cross section modifications.

Value engineering sessions identified drainage modifications to shorten the length of culverts that lowered cost and also reduced the length of underpass for fauna to cross through the corridor. - By Jo Moss