Power and Water provides water supply services to around 135,000 people across the Darwin region, managing everything from how our water is sourced, stored and treated through to the infrastructure that delivers it to homes and businesses.
Its passionate experts are committed to providing sustainable, high-quality drinking water to all Territorians now and into the future.
A big part of their role is to make sure there is enough water to support the growth and prosperity of the Territory for decades to come and meet the NT Government’s target of a $40 billion economy by 2030.
Eighty five percent of the region’s water supply comes from Darwin River Dam, with the rest sourced from the McMinns and Howard East borefields.
That water is then pumped to the Darwin region where it is used at the rate of about 43,000 megalitres per year.
The rate of water use is above the sustainable yield of our water supply system – even when factoring in upgrades by Power and Water over the past decade to maximise the operating capacity of infrastructure.
With demand for water in the greater Darwin region expected to more than double to almost 100 gigalitres per year by 2050, and water storage levels in the Darwin River Dam becoming increasingly affected by climate change and evaporation, it’s clear a plan is needed to secure water supply in the longer term.
Power and Water and the Northern Territory Government have collaborated to develop the Darwin Region Water Supply Infrastructure Program, which will roll out in two stages to deliver an extra 67,500 megalitres of water a year into our water supply system.
Stage one – Manton Dam Return to Service Built in the 1940s, Manton Dam was Darwin’s primary source of water until the Darwin River Dam was commissioned in 1972. Manton Dam was opened to recreation by the NT Government in the late 1980s and has been maintained since then as a potential future water supply.
Work is now underway to return Manton Dam to service, including installing additional treatment measures to ensure it meets stringent drinking water quality standards while also remaining an important recreational resource for the community.
Infrastructure investment of $190 million is required, including a refurbished intake tower, a new pumping station and pipeline, and a water treatment plant.
The project will take three-four years to complete. Once returned to service, Manton Dam will provide 7300 megalitres a year of water into the Darwin region water supply system.
Liam Early, the Lead Project Manager for the Manton Dam Return to Service project, is excited to lead the interesting and challenging project.
“Upgrading an 80-year-old asset is challenging,” he says.
“It is testimony to the original design and construction teams that the asset still has considerable life in the inlet structure and dam wall. The upgrades will extend the operational life of the assets by another 50 years.
“While 130 years may appear a long time for the life of such infrastructure, the Lower Stony Creek Dam built in 1872 in Victoria provided water supply to Geelong for 125 years and is the world’s third oldest concrete dam.”
Stage two – Adelaide River Off-stream Water Storage
The Adelaide River Off-stream Water Storage (AROWS) project will be an all-new water supply scheme with a yield of around 60,000 megalitres.
AROWS will take advantage of a natural geological basin in the Marrakai region south-east of Darwin and will be filled with water pumped from the Adelaide River during the wet season.
There is no infrastructure that will restrict the flow of the Adelaide River, meaning this is a far more environmentally friendly solution than a traditional instream dam. This large-scale project will take seven-10 years to develop and deliver and will be a vital enabler of future economic growth in the NT.
Both these initiatives are being supported by the Australian Government through the National Water Grid Fund, which will add significantly to our water security, ensuring we have enough supply to keep pace with projected demand.
Trevor Durling, Power and Water Senior Headworks Engineer, has been working on the development of the AROWS project for more than a decade and identified it as a water source option in the 2013 Darwin Region Water Supply Strategy.
“The AROWS project is an exciting, innovative project that will sustainably harness a proportion of the Territory’s water resources to enable growth and provide water security for generations to come.
“The work we’ve done with the Northern Territory Government to build a detailed business case has demonstrated that investment in Darwin’s water security is a sound proposition, and the timing is right.”
Connecting new supplies of water is one part of securing Darwin’s water future. The other is about continuing to manage demand.
Together as a community, we’ve made some important progress in cutting back on our water use over the past 10 years.
But our annual water demand is still above the sustainable yield of our supply network and well above the national average.
The Living Water Smart program has been a pivotal part of Power and Water’s efforts to manage demand, particularly in the Darwin region, helping lower residential consumption by about 20 percent over the past 10 years.
We all have a role to play in ensuring we have enough water for Darwin’s future.
The Darwin Region Water Supply Infrastructure Program is jointly funded by the Australian and Northern Territory governments, delivered in partnership with Power and Water.