Fauna Overpass Bridge | Western Australia

An integral piece of the new extension of Western Australia’s road network has attracted a lot of attention from the media – the State’s first fully vegetated, dedicated, fauna overpass bridge.

The Federal and State Governments invested $1.02 billion towards the NorthLink WA project to cater for increased traffic surrounding population growth in Perth, estimated to reach 3.5 million. The project saw upgrades and extensions to the Tonkin Highway out to the regional centre at Muchea connecting through to Ellenbrook. The infrastructure was built through a joint venture between BGC Construction and Laing O’Rourke.

The project aimed to:

  • Improve freight capacity, efficiency and productivity,
  • Reduce urban congestion now and into the future,
  • Improve road safety in line with the State’s ‘Towards Zero’ strategy,
  • Maximise sustainability through economic, social and environmental responsibility whilst,
  • Improving amenity for road users.

Special projects need special attention to detail

HydroPlan were approached to undertake the detailed design and specification for an irrigation system to establish the landscape for a fauna overpass bridge. We could not be prouder to be a part of minimising the highway’s impact on the movements of local native animals over the dual carriage way.

The irrigation system runs off supplied water from a groundwater bore in the vicinity. Sustainable options were investigated to power the submersible bore pump, although it was ultimately the reliability of the main power grid that proved the critical factor.

Additionally, a drip irrigation system was favoured as there was a need to minimise any attraction to native animals looking for water and consequently potential for damage by native animals. This drip system posed its own challenges with limited space and depth of cover across the bridge, an artificially undulating landscape and a groundwater bore supplying the system.

The fauna bridge is the first of three being built in the Metroner Yanchep rail extension.

Footage: @seenbylexo