With the issue of water supply reaching crisis point, its connection to climate change needs to spur urgent action.
Commentators have predicted we may see wars over water as the world’s potable water supplies shrink and the number of people needing water grows. What is often missing from the water discussions, though, is the degree to which managing our water resources more intelligently might also help win the battle against climate change.
There are a number of reasons why this is the case – for a start, the opportunities for decarbonising the “energy-water nexus”, a term that describes the energy footprint required to supply, purify and manage water resources.
The water supply system includes potable supply systems, urban water and waste water management and treatment systems. According to the Australian Water Association, this currently directly or indirectly influences around eight per cent of our national annual greenhouse emissions. Addressing the energy-water nexus is a key strategy for reducing this footprint, according to chair of Melbourne Water’s Board of Directors, John Thwaites.
Another way in which conserving water can be a climate ally is through the valuing of forest areas in catchment areas as both carbon sinks and water supply enhancers. A recent article in the Australian Water Association journal, for example, highlighted the need to stop logging in Melbourne’s largest water catchment to protect future supplies.
The missing link in terms of supporting this work, though, is a carbon price that balances the business case for trees as productive assets in-situ rather than their current valuation approach as extractable resources.
Yet another opportunity for financing the necessary measures is the inclusion of sustainability initiatives around water in green bonds, climate bonds and green loan investment vehicles.
Whatever motivation and set of benefits we pursue, approaching water from a stewardship perspective is vital. As Jacques Cousteau has observed, people tend to forget that the water cycle is actually the life cycle. There literally is no replacement for water in terms of maintaining the lives of humans and the entire biosphere we dwell within.
Sounding the alarm bells at UNSW
It is a paradox that even as our fresh water supplies are shrinking, climate change is generating more intense rain. A study released today [Thursday] led by Professor Ashish Sharma at the University of New South Wales has found an explanation for this.
The researchers found that part of the cause is the dryness of soils due to the prolonged drought conditions that are the new normal in many regions, including Australia.
“This is something that has been missed,” said Sharma, an ARC Future Fellow at UNSW’s School of Civil and Environmental Engineering.
“We expected rainfall to increase, since warmer air stores more moisture – and that is what climate models predicted too. What we did not expect is that, despite all the extra rain everywhere in the world, is that the large rivers are drying out.
“We believe the cause is the drying of soils in our catchments. Where once these were moist before a storm event – allowing excess rainfall to run-off into rivers – they are now drier and soak up more of the rain, so less water makes it as flow.”
The study utilised data from 43,000 rainfall stations and 5300 river monitoring sites in 160 countries.
Less water into the rivers means less water for our cities and agricultural areas. Drier soils also increase the amount of water agriculture requires for irrigation and watering.
But just as the soils are sucking up proportionally more of the rain before it enters water catchments, the cities are discharging more of it due to heavy rainfall events in areas that lack permeable surfaces such as soil to absorb the water.
“It’s a double whammy,” said Sharma. “Less water is ending up where we can store it for later use. At the same time, more rain is overwhelming drainage infrastructure in towns and cities, leading to more urban flooding.”
Sharma said that one solution is to wait for international agreements to curb greenhouse gas emissions to have an effect. But that will take a long time.
“The other option is to be proactive, and re-engineer our water systems so we can better adapt and cope.”
That means a need for new policies, new infrastructure, new farming practices and more pathways for creating green cities that have the capacity to store or divert flood water.
“We need to adapt to this emerging reality,” said Sharma. “We’re going to need re-engineering on a massive scale in some places if we are to continue living in them.”
He pointed to places like Arizona and California as exemplars in managing to make liveable places using minimal rainfall.
“Or take the Snowy Mountain Scheme: it’s not just about hydroelectricity, it’s also a complex water supply scheme with 225 km of tunnels, pipelines and aqueducts.
“There are no silver bullets. Any large-scale re-engineering project will require significant investment, but the cost of inaction could be monstrous.”
Water, water everywhere, but less of it is drinkable
Another impact of a falling water table that made the news this week was the revelation that sea water is now contaminating the water table around Kwinana in Western Australia, up to 1km inland, rendering the bore water used by industry, agriculture and residential areas there unsuitable for use.
This contamination has been caused by a combination of low rainfall and other factors not recharging the aquifer and increased demands on the aquifer through withdrawals.
A similar situation has been on the radar for Perth itself, with strategies implemented around managed aquifer recharge to replenish an aquifer running low due to increased population and corresponding water consumption.
Managed Aquifer Recharge (MAR) is an area CSIRO has been undertaking research into, including looking at the success of existing MAR projects.
Examples of the technique either already in use, planned or proposed around the country include one of the best-kept non-secrets in Perth: the pumping of recycled water into the city’s aquifer to top it up. However, at the consumer end it is still perceived as the same tap water it always was.
Do you take sugar in your coffee-infused dinosaur pee?
Despite the fact that even the expensive and branded bottled water many of us drink was probably once upon a time dinosaur pee, many consumers still baulk at drinking post-treatment recycled water sourced from their own urban area’s waste water.
This aversion is an oddity, when the science of the hydrological cycle and the basic physics and chemistry involved has proven that all the water we have on earth right now is the same water we have always had, recycled endlessly from oceans to the sky to the rivers and streams, via living things and then back to the sky, oceans or rivers – all of it driven by solar power.
Respect the resource with IoT and smarter thinking
Former managing director of South East Water and principal of Valid Consulting, Kevin Hutchings, told The Fifth Estate that we have to treat water with “the greatest of respect”.
“We are only custodians of it for a very short period of time, and we have got to put it back into the environment in better condition than we found it.”
Not doing so not only raises the spectre of limited resources; as history has shown, poor quality water can also kill us.
The cholera epidemics of the UK back in the 1800s, for example, were the result of water being contaminated with human effluent. One of the greatest public health advances was the invention of sewerage systems, which in London were designed by engineer Joseph Bazalgette in the 1840s.
Hutchings points out that it was a case of political will emerging due to the “great stink” of the polluted Thames making being in the British House of Parliament literally untenable.
In the current day, one of the things that makes political will around water management a challenge is the complexity of who owns which part of the entire system.
Where Hutchings sees opportunities is at the micro-infrastructure level of individual buildings and suburbs.
“When we are building new homes, we have to think differently about how we build,” he says. “Water has been the poor cousin to energy, but it can be so easily fixed.”
SE Water put this idea into practice with the planning and development of Aquarevo in Cranbourne. Being built in partnership with Villawood, the estate comprises 450 homes that will use around 70 per cent of the average Melbournian’s water consumption per person.
It’s being achieved through a combination of smart sewer systems, smart rainwater systems and re-thinking the plumbing so the rainwater is used for solar hot water for laundries, showers and baths, and rainwater also for toilet flushing and garden watering.
The use of Internet of Things technologies is the link, Hutchings explains, enabling the system to ensure rain tanks are at a level that will enable them to harvest optimum rainfall. Waste water tanks for the properties will discharge via a pressure sewer system in a way that “flatlines” the input to the estate’s water treatment plant.
This means that the sewerage and stormwater infrastructure can be designed at a smaller size to cope with reduced peak flows, reducing the energy footprint associated with sending waste water and storm distances long distances for treatment at large plants, and lower volumes of potable mains water needing to be pumped to the estate.
The result is a carbon winner, a water winner and a bottom line winner for both consumers and the water authorities.
“The whole IoT space allows for command and control of the house,” Hutchings says.
For any new estate, where the rooflines of homes are “almost touching” and there is insufficient ground surface area for storm water to soak in, Hutchings says that all homes should be capturing and using the water rather than requiring the building of barrel drains.
He says sewerage infrastructure and waste water infrastructure are some of the “laziest” infrastructure in our cities, being sized for peak event volumes, which rarely occur.
“We need to move the regulations along with emerging technology,” he says.
In the inner-city, where thousands of new residents are placing demands on infrastructure not designed for that large 24/7 population, it is not possible to harvest sufficient rainwater within the building footprint to make much of a dent in demand or in stormwater outflows.
“There is no option other than upsizing the infrastructure,” Hutchings says.
That’s where developer contributions come in, and, much as they might be regarded as a bugbear by the developer contingent, good sewerage is pretty much an essential. Cholera returning is not a good look.
Hutchings points out that in terms of the demand side of the equation, if water can be saved through better managing thousands of suburban rooftops and household usage, the capacity should be there to keep the taps flowing in the city apartments without needing to build more massive reservoirs or invest further in desalination.
Another technology that can help manage demand better in the inner city is smart metering at the individual dwelling level. A smart meter that has an acoustic data stream can indicate when and where a leak exists, Hutchings explains. If a suspect noise exists only for one dwelling, the problem is in that dwelling. If it exists in a group of dwellings, it is in a part of that system.
Just addressing leaks more effectively could improve supply capacity, as Hutchings says currently around 10 per cent of potable water that goes into the supply system is lost to leaks somewhere within the system.
“Digital metering allows us to do so much, not just know the volume of water being consumed.”
“We need to treat water with the respect it deserves.”
Hutchings can also see potential for disruptive new businesses to emerge in the utilities space that can offer consumers a way of leveraging data from smart meters for electricity, water and gas.
“We have information we are not using.”
A final thought about renewable energy
The US-based Energy Information Administration also cares about water. In a recent article at DeSmog Blog, recent data is cited that shows renewable energy such as wind and solar uses vastly less water than thermoelectric [fossil fuel or uranium-driven] power generation.
In fact, solar and wind require almost zero water to operate. The data shows that thermoelectric power generation is currently the leading use of water in America – consuming a whopping 41 per cent of supplies, the majority of that through evaporation or “blowdown” during generation.