A detailed business case recommended two projects as the best solutions to ensure water security for the Darwin region amid growing concerns over water supply.
- Darwin’s long-term water supply has faced increasing pressure due to population growth and climate change
- An analysis by PriceWaterhouseCoopers identified two projects as the best solutions
- The Northern Territories government supports the projects, but says federal funding is needed
The AROWS (Adelaide River Off-Stream Water Storage) and Manton Dam Return to Service (RTS) projects are expected to provide 67 billion liters of water per year at full capacity for the Darwin region, and construction is expected to cost 1.45 billion of dollars.
The AROWS project has long been promoted as a solution to Darwin’s water security needs, diverting floodwater from the Adelaide River – about 80 kilometers south of Darwin – to an off-stream basin during the season. rains.
Now, both projects have won the backing of a new business case led by professional services firm PriceWaterhouseCoopers.
Speaking to reporters on Tuesday, Power and Water Corporation chief executive Djuna Pollard said that “traditionally we basically had one main water source.”
“It is really time that we diversify our water supply so that we can provide a safe source of water in the future,” she said.
NT Water Safety Minister Eva Lawler said the projects would take a lot of work to get up and running.
“But the first and most important thing is to continue working with the Australian government around the funding of this project,” she said.
A solution for the next 50 years
Most of Darwin’s drinking water comes from the Darwin River Dam, built in 1972.
Before that, it was the Manton Dam, built in the early 1940s.
But an expanded population, a string of below-average rainy seasons in recent years and the growing effects of climate change have put increasing pressure on water levels at the Darwin River facility.
Two years ago, water levels plunged to their lowest since 2006, falling to 52% of peak capacity.
Water demand at the dam is already slightly above capacity.
By 2050, an additional 11 million liters are expected to be needed each year to meet population growth.
The Manton Dam RTS project is proposed as a short-term solution to this problem, with development work expected to take between three and four years.
Ms Lawler said the government was keen to start work as soon as possible in 2022.
“The work around the Manton Dam is environmental impact work, it’s around the design work that needs to be done…there is a new pipeline that will need to be installed as well,” he said. she declared.
The AROWS project is expected to last between seven and ten years, with work to include a water allocation plan for the Adelaide River, environmental impact assessments and consultation with landowners.
“This project will be the largest project undertaken by the Northern Territory Government, by Power and Water, since the railway was built a number of years ago,” Ms Lawler said.
“Don’t dam the Adelaide River”
Although the Manton Dam has not been used for drinking water for decades, it is now popular for swimming, water skiing and fishing, as one of the few sources of (mostly) free water. crocodile in the Northern Territories.
Ms Lawler said recreational use would continue for now with a decision to be made this year, but said it could continue to be used for both.
“There would be a cost around that, but there is an infrastructure solution around water treatment to ensure Manton Dam can continue to be used for recreational purposes,” she said. declared.
She also reassured Territorians that the AROWS project would not build a dam on the Adelaide River.
Amateur Fishermen’s Association chief executive David Ciaravolo told the NT Country Hour that the off-river storage system was preferable to damming the Adelaide River, but said the design should be “well balanced”.
“We need to ensure that the drawdown from the Adelaide River arrives at the right time and only in the quantities that are ecologically appropriate,” Mr Ciaravolo said.
“And of course the other thing that we have to be sure of is that when they take that water, there’s proper filtering from those pumps.
“There are estimates that millions upon millions of fish are killed every year in the Murray-Darling system due to water pumping and we need to make sure that doesn’t happen here.”