As of March 2017, water levels in Sydney and Melbourne dipped to 85.9% and 67.3% of capacity respectively. Last decade’s Millennium Drought brought those numbers to a critically low 32% and 25.5% before the skies opened up.

An extra million people – or two or three – in a similar scenario, combined with increasing temperatures, has the potential to spell disaster.

In the works

Fortunately, double the people doesn’t equate to double the water usage. “Demand from our water supply system is projected to rise from around 530 billion litres per year to 740 billion litres per year by 2064,” said Sydney Water’s Principal Analyst Marcia Dawson.

“For comparison purposes, total water demand in 1990-91 was 665 billion litres a year, and there were around 1.2 million fewer people in Sydney than now.”

This reduction is due to a range of factors, including more apartment living, improved appliance efficiency, requirements for water-efficient housing, changes to industry, increased recycling and the ongoing success of education campaigns since the Millennium Drought.

For example, Melbourne Water reintroduced a voluntary water efficiency program called Target 155 just last year.

“The average water consumption in Australia is around 200 litres per day per person,” said Sandra Dodds, chief executive of urban infrastructure for Broadspectrum.

“But where there have been challenges around water, we’ve seen that we can reduce that to 100 litres a day through innovative water-saving solutions, or reviewing usage patterns and influencing a better usage approach.”

However, educating the public is far from a silver bullet.

"As populations continue to increase, more investment will be needed, particularly in ‘manufactured’ water sources such as recycled water and desalination, to supplement supply,” Dawson said.

Push to start

How else will authorities and utilities in Sydney and Melbourne keep up with their population booms? Through a mix of new technologies, smarter water recycling systems and a dose of right place, right time strategic planning.

“The location and timing of growth is important,” Dawson explained.

“Infill-type development in systems already at capacity, or new development in areas with tough terrains, are more expensive for us to provide services to.”

Meanwhile, Melbourne Water is implementing a range of strategies, including working with customers to harvest stormwater, reusing treatment plant effluent and increasing connectivity across its water supply system.

Infrastructure is taking a central role. Sydney Water’s total infrastructure budget for 2016-2020 is $2.2 billion. Projects include commencing construction of a $27 million project at Oran Park to create a new wastewater pumping station, and 8km of pipelines that will cater for 7000 new dwellings.

They’re also working with the City of Sydney on a $100 million project to construct a 2.4km underground stormwater drain servicing 40,000 residents moving into Green Square.

Melbourne Water, on the other hand, delivered $83 million in capital works over the past 12 months to sustain its water supply system, according to Chris Williams, general manager of integrated planning.

This included renewing ageing water transfer assets, the largest being the Essendon-to-Footscray pipeline
($16.8 million), as well as investments to meet population growth predictions, particularly the St Albans-to-Werribee pipeline ($11.2 million).

But fears persist that the industry as a whole is leaving its run a little too late.

“In broad terms, there are areas where I don’t think we are keeping pace in Australia,” said Scott Rudram, director at Atlas Engineering Group.

One reason is a hesitation to invest in emerging technologies that do not have a locally proven track record.

“People rarely want to be on version 1.0. They want somebody else to go through the hard yards and then jump on board for version 1.3 or 1.5,” Rudram said.

Razor’s edge

Population growth is far from an isolated challenge, according to Manager of City Shaping at Sydney Water Paul Mulley.

An ageing asset base, environmental standards, rising energy prices and climate change will put pressure on prices for water, wastewater and stormwater services over the long term.

Then there are challenges associated with increased runoff from densification.

“With more impervious surfaces such as roads and roofs, higher temperatures and runoffs are expected,” Mulley said.

“We’ll need to provide infrastructure solutions for flooding, such as we did at Sydney’s Green Square.”

It’s also important the environment isn’t overlooked.

Professor Jurg Keller, chief research officer at the CRC for Water Sensitive Cities, said liveability and sustainability issues are severely underrated factors when planning for a community’s future.

That’s because planning decisions are often made on economic principles. But how do you appraise a single tree? Is it in the cool shade it offers, the community meeting area it creates or the runoff water it soaks up?

“Turning all that into a single dollar value is a key challenge,” Keller said.

He added that another challenge in growing cities will be the increased pollutant concentration in wastewater.

“Sewer lines will run slower and have longer runs, which means they will smell more and have more corrosion issues.”

And there are budgets to consider, which have dropped in recent years.

“The trend is for asset owners to extend the life of existing water plants and facilities by investing in upgrades as opposed to building new assets,” said Broadspectrum’s Dodds.

Known unknowns

Where challenges beckon, opportunity knocks. For example, changes to urban landscapes mean more alternative water resources such as stormwater, said Melbourne Water’s Williams.

We will start to see more and more of this way of thinking, added Keller.

“With new developments we’re starting to think ‘hang on, do we need to supply potable water for everything we do?’. You can’t take that approach in existing developments because it’s just too expensive,” Keller said.

“Take a look at the electricity sector,” added Dodds.

“People are now generating their own power and selling it back to the grid. We need to look at ways to empower the consumer to become more self-sufficient, such as using rainwater for flushing the toilet instead of using potable water,” she said.

In the short term, public education will remain the industry’s main hedge. This is partly because it’s not time for panic stations and, as Rudram pointed out, we truly don’t know what the future holds.

“Over the past 15 years, there’s been such a proliferation of new technology that to plan accurately for the next 15 years is really difficult,” Rudram said.

“So the strategy has to be adequately agile and have enough insurance built into it that it can adapt as technology develops and as opportunities present themselves.”

First published in Current magazine May 2017.