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Adelaide River Off-Stream Water Storage


Water is one of our most precious resources and as the Territory grows, water security is critical – for people, agriculture and industry.

In the greater Darwin region, the majority of our water supply, around 85 percent, comes from the Darwin River Dam, which is operating at or above its sustainable supply level. The remaining 15 percent is provided through groundwater resources, which is also in limited supply.

In other words, the supply is operating at its sustainable capacity.

Funded by the Australian Government’s National Water Grid Fund, and in partnership with the Power and Water Corporation, the Northern Territory Government has completed a detailed business case to investigate options and identify a preferred solution for securing the Darwin region’s future water supply.

The detailed business case undertook a comprehensive assessment of a range of options, including desalination, water recycling, in-stream dams, such as the Upper Adelaide River Dam and Manton Dam, and the Adelaide River Off-stream Water Storage (AROWS) project. 

The detailed business case identified Manton Dam Return to Service (RTS) and the AROWS project as the recommended infrastructure solution, to be developed in two stages:

Stage 1– returning Manton Dam to service; a short-term solution with a development timeframe of three to four years

Stage 2 – AROWS; long-term water supply, with a development time frame of seven to 10 years

Returning Manton Dam to service and delivering AROWS will provide access to an additional 67,000 megalitres of water per year – around double the water supply capacity of Darwin River Dam.

As the Territory grows, water security is ever more important and beneficial to Territorians, business and agriculture. For instance, it will help unlock new agribusiness regions in the Top End as part of the push to boost national production from $65 billion today to $100 billion.

Department of Industry, Tourism and Trade chief executive, Shaun Drabsch, says: “The detailed business case found that this staged infrastructure program has a positive benefit cost ratio, demonstrating this is an economically viable project and providing a robust justification for investment.”

For the past decade, Power and Water have been laying the groundwork for the Infrastructure Program having identified Manton Dam and AROWS as the preferred short and long-term water supply solutions in their Darwin Region Future Water Supply Strategy.

Power and Water Corporation chief executive Djuna Pollard says: “It is time that we diversify our water storage capability so that we can provide a secure water supply moving forward.”

Their technical specialists have undertaken a significant body of preliminary work to inform the design and delivery of both projects.

“We are looking forward to continuing to work closely with the NT and Australian governments to progress the next stages of planning for both AROWS and the Manton Dam Return to Service projects,” says Ms Pollard.

Detailed designs for the refurbishment of the intake tower, a new pumping station and the new Strauss water treatment plant are well advanced for the Manton Dam RTS project.

Environmental studies, including species habitat surveys, and a heritage management plan for Manton Dam’s original infrastructure are also underway.

Building on the work completed by Power and Water to date, the NT Government will shortly commence a range of activities to support the development of the AROWS project. This will include:

  • the development of a Water Allocation Plan for the Adelaide River Catchment;
  • undertaking a comprehensive environmental approval process;
  • wide-ranging stakeholder engagement and community consultation.

With a seven to 10 year development timeframe, the NT Government will work with the community to inform the important decisions that need to be made to progress this Infrastructure Program.

The $1.5 billion Infrastructure Program is a nationally significant water infrastructure initiative, which will provide water security in the Darwin region for the next 50 plus years, and underpin economic growth in northern Australia.

It will be the largest public infrastructure project in the Territory since the completion of the Adelaide-to-Darwin railway 20 years ago.

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  • No dam infrastructure that restricts the flow of the Adelaide River
  • Development timeframe seven to 10 years
  • Could supply an additional 60,200 ML per year, which is around x2 the supply capacity of Darwin River Dam
  • Economically viable
  • Ensures long-term water security for the Darwin region
  • Unlocks sustainable, long-term economic development
  • Innovative approach that provides complementary outcomes of water availability and environmental sustainability