The Times Australia
The Times World News

.
The Times Real Estate

.

Sydney's dams may be almost full – but don't relax, because drought will come again

  • Written by Ian Wright, Senior Lecturer in Environmental Science, Western Sydney University
water spills from dam

Dams serving capital cities such as Canberra, Hobart and Sydney are near full[1] after two years of widespread rainfall[2]. But these wet conditions won’t last.

Under climate change, droughts in Australia will become more frequent and severe[3]. Our drinking water supplies, and water crucial for irrigation and the environment, will dwindle again.

Sydney, Australia’s most populous city, is among those that must prepare for the next drought. The NSW government is developing[4] the Greater Sydney Water Strategy, to guide water management in coming decades.

Among the plan’s more contentious proposals are increased use of Sydney’s existing desalination plant and expanding the use of recycled water (highly treated sewage), including for drinking water. So let’s examine whether such measures are enough to secure Sydney’s water future.

water spills from dam
Water has been spilling from Warragamba Dam, but dry conditions will eventually return. WaterNSW

A city of water scarcity

During the most recent drought from 2017 to 2020, Sydney’s water storage levels dropped by 50% of full dam capacity in two years – a much faster depletion than in previous droughts.

Inflows into Sydney’s dams have dropped over the past 30 years. From 1991 to 2020, inflows averaged 770 million litres a year – 45% less than the long-term average.

The news isn’t all bad. Sydney used less water in 2019-20 than it did in 1990, despite its population growing from 3.8 million to 5.4 million.

But as the Greater Sydney Water Strategy states[5], increasing climate variability means that, without action, the city could face a shortage of drinking water as periods of severe drought become longer and more frequent.

delighted boy holds hose
Sydney must prepare for a drier future. Brendan Esposito/AAP

Desalination for the nation?

The strategy raises the prospect of increased use of Sydney’s existing desalination plant, and building a second plant in the Illawarra region south of Sydney.

Desalination removes salt from sea water to create drinking water. The Millenium drought – from the late 1990s until 2010 – prompted several major Australian cities, including Sydney, to build desalination plants[6].

The technology can revolutionise water supply. For example, in 2020-21, Perth’s two desalination plants supplied 47% of the city’s water. But desalination plants can also face limitations and challenges.

The plants are expensive to build and to operate – and can sit idle for years, as the Kurnell plant did between 2012 and 2019. This can make them politically unpopular and see them criticised[7] as “white elephants”.

Even at full production, the Kurnell plant produces only 15%[8] of Sydney’s daily demand. And while an additional plant in the Illawarra will extend desalinated supply to more households, the technology can’t supply water to all parts of Sydney due to the city’s complex distribution infrastructure.

As I discuss below, expanded use of recycled water is a better option for Sydney than more desalination.

Read more: Melbourne's desalination plant is just one part of drought-proofing water supply[9]

Ocean wave with land in background
Desalination removes salt from seawater. Nick Bothma/EPA

Can we stomach recycled water?

Many Australian cities, including Sydney, already use recycled water – sewage that has been heavily treated – in applications such as watering golf courses and parks, flushing toilets and fighting fires.

The draft plan raises the prospect of also adding recycled water to drinking supplies, which has long been a vexed issue in Australia. Some people oppose it on health grounds, while others just can’t get over the “yuck” factor.

The concept of recycled water has a lot going for it. For example, analysis[10] suggests it would be far cheaper and use much less energy than desalination.

Making better use of recycled water would also reduce the environmental impact of disposing of wastewater in rivers and oceans. And the potential supply of recycled water will only increase as populations grow.

Finally, good recycled water projects are used continuously, not just at times of water stress. The Rouse Hill recycled water scheme in Sydney, which supplies[11] 32,000 properties for non-drinking water uses, is a great model.

The draft plan says recycled water would not be added to drinking supplies without public support, but past history suggests this may be hard to achieve. In 2006, for example, Toowoomba residents rejected a plan[12] to drink recycled water, despite the town facing a grave water shortage.

However, as urban water supplies become ever more scarce, Australians may have to get used to the idea of drinking recycled water – and authorities will have to find new and better ways of selling the concept to the public.

The Sydney water plan recognises this. It emphasises the need for public consultation, and raises the prospect of investing in a recycled water demonstration plant to “highlight the safety of demonstrated and proven technology”.

Read more: When water is scarce, we can't afford to neglect the alternatives to desalination[13]

man leans towards water in front of Sydney Harbour Bridge
Better use of recycled water would reduce wastewater flows to Sydney’s beaches and rivers. CSIRO

A major omission

The plan shows how Sydney’s growing population could sustainably adapt to to a drier future. But it ignores one important measure for reducing water use - charging[14] customers a penalty for excessive water use.

Under the measure, also known as an “inclining block tariff[15]”, the rate per unit of water increases as the volume of consumption increases.

Research has shown[16] water pricing can be an effective way to manage water scarcity, as well as helping water utilities recover the costs of their services. Australian cities such as Melbourne, Canberra and Brisbane apply inclining block tariffs to water, but Sydney does not.

Sydney Water’s price regulator, IPART, has argued against[17] charging high water users more, saying it would provide less incentive for smaller households to conserve water and impose unfair costs on larger households.

Granted, water pricing is a complex[18] issue and may require protections[19] for lower-income users and the environment.

But under worsening climate change, our major cities cannot eschew any opportunity to ease pressure on water supplies.

References

  1. ^ near full (www.bom.gov.au)
  2. ^ widespread rainfall (theconversation.com)
  3. ^ frequent and severe (www.theguardian.com)
  4. ^ developing (www.industry.nsw.gov.au)
  5. ^ states (www.industry.nsw.gov.au)
  6. ^ desalination plants (theconversation.com)
  7. ^ criticised (www.abc.net.au)
  8. ^ only 15% (www.water-technology.net)
  9. ^ Melbourne's desalination plant is just one part of drought-proofing water supply (theconversation.com)
  10. ^ analysis (www.smh.com.au)
  11. ^ supplies (www.sydneywater.com.au)
  12. ^ rejected a plan (www.theguardian.com)
  13. ^ When water is scarce, we can't afford to neglect the alternatives to desalination (theconversation.com)
  14. ^ charging (www.infrastructureaustralia.gov.au)
  15. ^ inclining block tariff (press-files.anu.edu.au)
  16. ^ Research has shown (www.sciencedaily.com)
  17. ^ argued against (www.ipart.nsw.gov.au)
  18. ^ complex (academic.oup.com)
  19. ^ protections (www.sciencedirect.com)

Read more https://theconversation.com/sydneys-dams-may-be-almost-full-but-dont-relax-because-drought-will-come-again-170523

The Times Features

Why Regional Small Businesses in Bendigo Deserve Better Access to Finance in 2025

In the heart of regional Victoria, Bendigo has long stood as a beacon of innovation, resilience and community spirit. As we step further into 2025, the importance of nurturing sm...

Is It Time for a Deep Cleaning? Signs You Shouldn’t Ignore

Most people know they should visit the dentist for a regular check-up and cleaning every six months. But sometimes, a standard cleaning isn’t enough. When plaque and tartar build...

The Hidden Meaning Behind Popular Engagement Ring Cuts

When it comes to engagement rings, the cut of the diamond is not just about aesthetics. Each shape carries its own symbolism and significance, making it an important decision for...

Annual Health Exams in the Office: How They Can Reduce Sick Days and Healthcare Costs

Regular health check-ups, especially annual health exams in the office, can significantly impact the overall well-being of your workforce. A proactive approach to employee health...

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping