Sydney Desalination26 August 2008
Dr Gareth Evans looks at how Australia is calling on the seas to ease the threat of drought in the sunburned country.
Australia – naturally one of the driest inhabited lands on the planet – has never enjoyed a great abundance of water, but in recent years the situation has taken a significant downturn as the country has been forced to endure a prolonged drought of almost epic proportions. May 2008 was Australia’s driest month since records began and came against a decade-long background of rainfall deficit and record high temperatures that have seen the nation’s water reserves put under severe stress, particularly in the east and southwest of the country.
The three-month period from March to May 2008 bore witness to severe rainfall deficiencies across large parts of Australia, exacerbated by an early end to the northern wet season, a poor start to the southern rains and the fourth driest autumn on record across the Murray-Darling Basin. With little rainfall in recent months, large areas of deficiency have developed throughout central and southern parts of Australia, while the combination of record-breaking heat and widespread drought in the past five to ten years is unprecedented in southern and eastern Australian history.
The ramifications of this for the country are enormous. According to the Australian Conservation Foundation (ACF), Australians are some of the world’s highest water users on a per-capita basis, but it is not simply a question of domestic consumption.
Australia is the third-biggest wheat exporter after the US and Canada, but the present Big Dry has led to disappointing crops and empty grain silos, which have made their own contribution to world shortages and rising global food prices.
Unsurprisingly, easing the effects of drought and safeguarding the future has assumed enormous practical and political importance.
Solutions for Sydney
In early 2007, a Commonwealth Scientific and Industrial Research Organisation (CSIRO) report painted a disturbing picture of the future for Sydney. The study into the effects of climate change on Australia – described as "a doomsday scenario" by the NSW Premier Morris Iemma – calls for water consumption to be cut by more than half in the next 20 years to avoid the city being faced with an almost permanent state of drought.
Sydney has not been slow to address these issues. The city’s desalination project – intended to produce up to 250 million litres of water a day, with a future option to scale up to twice that amount – is one of the key elements in the New South Wales (NSW) Government’s Metropolitan Water Plan.
Scheduled for completion in 2009, the plant is being built at Kurnell in Southern Sydney and will use wind energy substantially for its operation. A new pipeline will carry product water across Botany Bay from the Kurnell site, connecting with the city’s main water supply tunnel at the inner city suburb of Erskineville.
Desalination is not the only initiative being implemented to secure the city’s long-term water supply. Sydney Water is also aiming for a more than three-fold increase in water recycling – from the present annual 22 billion litres to 70 billion by 2015 – and has a yearly budget of AU$100 million to minimise losses from its network of pipes.
Although Sydney’s leakage is low by industry standards, this allows more than 18,000km of pipelines to be inspected each year to ensure it stays that way.
The rising tide of desalination
Desalination is looking increasingly attractive in the water-scarce regions of the country, such as the NSW central coast – currently experiencing the most severe drought on record. Developing solutions to mitigate the shortages and avoid serious reduction in the available supplies to both businesses and homes has led a number of councils to examine the benefits of seawater desalination, alongside less radical contingency measures.
The Gosford and Wyong Councils’ Water Authority, for instance, has explored the potential of initiatives to reduce primary demand, additional groundwater sourcing, effluent recycling and connecting to the neighbouring Hunter Water Corporation supply.
However, a feasibility study by consultants MWH for a 7,000 million litres a year desalination plant has led the councils to consider the option as a solution of last resort to their burgeoning water shortages.
To the north, on the Queensland/NSW border, at Tugun on the Gold Coast, a desalination plant is being built that will yield 125 ML/day. It could potentially feed into a regional water grid – a concept being developed by the Queensland Government with South-East Queensland Water and local government.
The state’s 50-year plan – published in 2007 – suggests building five more plants for: Queensland’s Sunshine Coast as well as plants on Bribie, North Stradbroke and South Stradbroke islands after 2028.
This move towards desalination is already underway; in November 2006, Western Australia became the first state in the country to use seawater reverse osmosis (SWRO) – a separation process that, by the use of pressure, forces a solution through a membrane allowing only pure solvent to pass through. The logic is compelling; seawater desalination is essentially climate-proof and, with all eyes focused on the looming threat of anthropogenic climate change, the advantages of an approach that can produce at full capacity in the face of dwindling rainfall are clear.
At a time when reservoirs are shrinking, groundwater is not replenished and rivers dry up, desalination offers what many see as the perfect counter to the increasingly hostile shift in Australian weather. However, critics argue that the process could make future droughts worse – the heavy energy demand of desalination plants itself contributing to further climate change.
Despite its obvious appeal, desalination is unlikely to offer the complete answer. Water reclamation initiatives, such as the reverse osmosis plant at Kwinana, Western Australia and the Western Corridor Recycled Water Project in Queensland, could make a significant contribution to easing the country’s problems.
However, perhaps the most ambitious – and potentially controversial – approach to emerge is to move water from the less populated north to the drier urban south. In April 2008 Australian Water Resources Minister Malcolm Turnbull published a report suggesting that piping water from rivers in NSW to south-east Queensland would be cost-effective.
Nevertheless, in the same month, the whole idea suffered a major setback when the Queensland Government abandoned plans to pipe water from the Burdekin Dam, Queensland to the drought stricken south-east after a Government-funded study estimated costs at AU$14 billion. According to Craig Wallace, the State Natural Resources Minister, going ahead with the project would effectively quadruple the price of water to consumers.
This cost issue surfaced again at the Charles Darwin University water symposium in June. Based on trials in Western Australia, environmental and ecological economist Adam Drucker indicated that desalination would be five times cheaper than shipping water from the Northern Territory’s Top End to meet the needs of southern states. Moreover, as he pointed out, the water that was present in the state was already key to much of the region’s economy.
However, as Professor Will Steffen, a climate change expert from the Australian National University, explained: "The future of water in the Top End is topical and is likely to remain so." For the moment at least, the idea is liable to continue to be viewed as one possible solution to Australia’s water worries.
In January 2008, David Jones, head of climate analysis at Australia’s Bureau of Meteorology warned that it might be time to stop viewing the south east of the country as drought-stricken and accept the extreme dryness as a permanent feature of the nation’s new climate. With the announcement six months later that the situation – particularly in the Murray-Darling river system, which drains one-seventh of Australia’s land mass in the eastern states – is worsening as prospects fade of the cooler months bringing drought-breaking rains, his words have begun to look distinctly prophetic.
Easing the situation calls for innovative thinking, and fortunately Australians are nothing if not resourceful.