Constrained by a tropical climate and the client's operational needs, Ventia meticulously planned and staged the remediation of an extensive drainage network at an Air Force base in Australia's Northern Territory.

Located approximately 330km south of Darwin, the RAAF base at Tindal provides forward mounting air force capability and hosts international personnel for training and exercises.

From November to April each year (the wet season in tropical Australia), the base receives an average four metres of rain. To avoid flooding, the base is surrounded by a network of open drains.

Ventia was engaged to redefine, repair and assure the functionality of this open drainage network to protect airfield capability and improve base safety.

As drains can only be serviced outside of the wet season, a project of this size had to be carefully planned and split into stages.

Keeping the airfield running

The client's highest priority is maintaining the airfield's functionality and availability, so this was the focus of Stage 1, delivered from August to November 2019.

The issues were serious: drains that service the airfield were blocked with silt, vegetation and detritus. In several areas, drainage walls had collapsed and erosion had widened drains, causing impact to the integrity of hardstand areas and taxiways.

Moving on to less urgent work

Having prioritised the airfield, we conducted a detailed survey of the entire draining network in Stage 2, re-scaling against topography, and removing soil, silt and vegetation.

Early scoping for Stage 3 to include cleaning and clearing of the underground drainage work.

A challenging environment

As well as working around the wet season, we've had to make sure we don't get in the way of Department of Defence activities.

Other challenges for the project included:

  • security and access risks from working adjacent to the airfield
  • contamination including from PFAS, PFOA and asbestos
  • working with heat, dust and wildlife.


We worked in close collaboration with the base redevelopment and operational teams to identify priority works and guarantee continuity of Air Force capability.