What Can Australia Teach California About Drought?

As California enters its fifth year of drought, finding fresh water and more efficient ways to use it has become more important than ever. Even if El Niño brings some relief to southern California this winter, as is currently expected, people in the state have realized that they need to prepare for a drier future. Much of California relies on Rocky Mountain snowmelt for water—and scientists have predicted that source will dwindle over the coming decades.

Increasingly, California is turning to Australia for solutions. Australia, an already dry country, has suffered through similar circumstances. The southeast portion of the continent experienced the “Millennium Drought,” receiving less-than-average precipitation for more than a decade from 1997 to 2009. And the far western city of Perth is quickly becoming one of the driest in the world. 

“The precipitation now doesn’t fall in the right place, it doesn’t fall at the right time,” says Anas Ghadouani, executive director of the Cooperative Research Centre for Water Sensitive Cities and an environmental engineer at the University of Western Australia.

Transferring the lessons of Australia to California isn’t as simple as copying a list of technologies used on the southern continent and applying them to the Golden State, Ghadouani says. “You can’t just have a house with everything in it; it will be cluttered.” The trick is to find which combination of solutions will work in each city and town. “That’s what the challenge is,” he says. “What is the right solution for you?” Here are a few of Australia's water-management methods that might help the parched state:

Drinking Saltwater

By the end of 2016, the people of San Diego may be drinking water drawn from the Pacific Ocean. The desalination plant slated to come online at that time in southern California has proven controversial because the technology is expensive, requires a huge input of energy to turn seawater into freshwater, kills ocean organisms sucked into the plant and releases a salty brine back into the ocean that could destabilize the ecosystem.

Then there’s the rocky history of desalination in Australia. The people of Melbourne are paying for a desalination plant that has never delivered a drop of water. Construction on the plant began during the Millennium Drought, but by the time it was turned on in 2012, rains had returned and reservoirs had refilled.

“It’s a sizable chunk [of the utility budget], and it’s just sitting there. A lot of people … rightly feel like they were cheated,” says Stanley Grant, an environmental engineer at the University of California, Irvine, who has studied how Melbourne dealt with the drought. But with the Melbourne region expected to add a million residents or more in the coming years, the plant will probably be needed in the future, he says.

And the technology has proven its worth in Perth. The city now has two desalination plants, the first of which went online in 2006, and they supply about 45 percent of the city’s drinking water. “What we’re seeing is maybe a new epic in human history where we’re now beginning to look for lower-quality sources of water,” such as seawater, runoff and even wastewater, says Grant.

Recycling Wastewater

After you flush your toilet, wash your clothes or run the dishwater, the water flows out of your home and to a wastewater treatment plant, where solids are removed and the water is cleaned of contaminants. Traditionally, these treatment plants release their water into a river or the ocean where it is diluted, but in Western Australia, some of that water is now recycled. It irrigates golf courses and crop fields, flows through toilets or is used in industrial processes.

The Water Corporation of Western Australia, which manages Perth’s water and wastewater, has set a goal of recycling at least 30 percent of wastewater by 2030. And in coming decades, some of that water could even end up as drinking water. Following a successful trial, treated wastewater will soon be pumped into Perth aquifers, replenishing what humans have removed. “We want to return every bit of water that we can to the ground and then eventually be able to use it later on,” says Ghadouani.

“Recharging water is something that happens naturally,” he notes. Groundwater recharge has the potential to increase water supplies at less cost than either building desalination plants or expanding reservoirs, scientists have found. The method is now gathering fans in California, where the drought has badly drained underground aquifers. And the Sanitation Districts of Los Angeles County has authorized a small demonstration project to test the technology.

Reusing Water

In Australia, “people have become really creative” about water, says Ghadouani. Greywater—the water that has been used for showers, baths and washing machines—doesn’t even need to leave the house to be reused. Diversion devices can take greywater directly to the yard or toilet. And for uses that require cleaner water, such as washing machines, homeowners can install treatment systems that filter and disinfect greywater. The water that washed your clothes last week can be cleaned in your home and used to wash your clothes the week after.

Graywater reuse is now coming to California. Changes to the plumbing code were required before anyone could divert water from their sink to their lawn, and it’s still only allowed if the water pipes discharge below soil or mulch (sprinklers are a no-no, but drip irrigation would work). And companies are beginning to market greywater recycling systems to Californian homeowners. The Nexus eWater system even extracts heat from greywater to warm a home’s hot water tank.

Green Infrastructure

Many American cities have embraced green infrastructure—networks of water systems and green spaces that work to clean water and provide a healthier, often more beautiful, urban environment. But water laws sometimes work against best efforts in the United States. In Colorado, for instance, it is illegal to capture rainwater, something that became legal in California only in 2012.

Australians have worked to integrate green infrastructure and connect projects, Ghadouani says. Developers are now required to not only put in green space, for instance, but that space also provides specific services, such as cleaning water. During Melbourne’s drought, the city “definitely innovated in that area,” Grant says, and low-tech options proved popular. Rain barrel use, for instance, nearly doubled from 16.7 percent of households in 2007 to 29.6 percent in 2010, Grant and his team reported in WIRES Water earlier this year.

Changing Behaviors

Technology, both simple and complex, has proven useful in Australia. “But honestly I think the biggest story is a behavioral story—somehow the utilities managed to mobilize people around this idea that if they didn’t change their water use behavior the city would run out of water,” Grant says. “Technology definitely helped, but it was almost marginal in terms of getting through the drought.”

In Melbourne, people started taking shorter showers, and some people even began taking a bucket into the shower with them to collect water for reuse. Many of these behavioral changes stuck; even five years after the end of the drought, people were using less water than before, Grant and his team found. And when homes are built in Western Australia, builders and designers often consider how to build in systems to use less water and energy.

Californians will need to change how they relate to water, similar to how Australians have dealt with their declining supplies, Grant says. But drought can be an opportunity to make changes that make cities and countries more resilient to droughts of the future. Droughts, he says, can be “the beginning of something that’s much more profound.”

Sarah Zielinski | | READ MORE

Sarah Zielinski is an award-winning science writer and editor. She is a contributing writer in science for Smithsonian.com and blogs at Wild Things, which appears on Science News.