Tackling climate change is everyone’s responsibility and water utilities across the globe are responding by championing innovation to deliver sustainable water services and safeguard water security. SA Water’s pursuit of large-scale renewable energy generation to reduce emissions from its operations is leading the charge, and now the utility is exploring how the smart use of water can help combat the effect of our warming climate.
From the state’s major airport to suburban backyards, the South Australian water utility is proving the natural cooling power of water is flush with economic and social merit, creating more liveable cities.
A world-first trial at Adelaide Airport
The extensive hard surfaces and dry, open land at airports worldwide mean they can often become sources of increased heat, exacerbating the impact of extreme temperatures during summer.
SA Water’s world-first heat mitigation trial with Adelaide Airport, which has been underway for three years, has found smart watering to maintain soil moisture and cultivate green space can reduce average ambient temperatures by more than three degrees on warm days.
More than 40 temperature and humidity sensors monitored conditions in the irrigation area, and the cooling effect is the result of evaporation from the soil profile, along with the transpiration of moist air from vegetation.
The concept creator, SA Water Manager of Environmental Opportunities, Greg Ingleton, said the methodology could lead to a sustainable reduction of an airport’s carbon footprint.
“Jet engines work better in cooler, denser air, using less fuel during take-off and being better able to carry their optimal passenger and cargo loads,” Mr Ingleton said.
“In warmer, less dense air, planes must travel faster down the runway to produce the lift needed for take-off. When a runway lacks the distance required to reach these speeds, a plane’s weight must be lowered, or the aircraft needs to use more fuel, impacting commercial aspects of an airline.
“Two years ago, in Arizona in the US, 50 flights were cancelled in one day due to it being too hot for the planes to take off.
“We can reduce the risk of this happening at many airports in Australia and across the world, by employing irrigation to green buffer land around the runways.”
Adelaide Airport’s Sustainability Manager, Leigh Gapp, said the trial has the potential to benefit airline customers on hot days through reduced fuel burn, which in turn reduces the carbon emissions associated with take-off.
“Reducing the ambient temperature can also reduce terminal energy costs associated with cooling. We are continuing to explore both of these options,” Mr Gapp said.
Recycled water from SA Water’s nearby reuse scheme was applied to four hectares of lucerne 600m south of the airport’s runway, twice a week at night, to create the cooling effect, and also showed the space could produce revenue-generating food crops – evolving historical land management practices.
The trial opens the door to opportunities for conceptualising airport land as spaces that grow profitable crops to achieve cooling, create zones of cooler air that flow to surrounding suburbs, protect travellers from extreme temperatures and generate economic savings by buffering aircraft operations.
Taking flight to share airport cooling with the world
Demonstrating the potential for airports globally, the encouraging findings from SA Water and Adelaide Airport’s trial were shared with more than 1,000 delegates at the Airports Council International’s Airport Exchange 2019 – one of the aviation industry’s peak annual conferences – in Abu Dhabi.
Together with Adelaide Airport, the utility showcased their learnings with some of the world’s largest airports, including Dubai, London Heathrow and Munich.
Mr Ingleton said interest in their innovative approach to airport landscape irrigation was high among the industry.
“Hot and dry landscapes at airports can lead to several operational challenges and our concept has the ability to overcome these challenges, while cultivating broader economic and social value,” Mr Ingleton said.
“Our recent economic analysis, which was based on expanding the irrigation area to 200 hectares, suggests initiatives like this can provide a range of operational efficiencies and wider benefits for airports, such as visitor experience and environmental sustainability.
“We’re also investigating the ability to create carbon credits from growing the crops, demonstrating carbon sequestration whereby the plants absorb CO2 and use it as fuel for growth by locking it in the soil.
“Sharing our insights with a global audience encourages collaboration with airports worldwide – helping them benefit from our knowledge and capabilities, while generating opportunities for SA Water.
“Expanding our exposure and experience to diverse climates and landscapes will also enhance our capability right here in South Australia, and help implement heat mitigation in a range of other urban environments, such as schools and council parks, to improve liveability.
“By supporting green infrastructure and the intelligent use of water, we can cool urban areas and reduce the impact of heatwaves and climate change.”
SA Water’s pioneering concept turned heads in Abu Dhabi, prompting interest and knowledge sharing with airports across the Middle East, India and Australia since the conference.
Expanding the concept to the urban environment
As Australia’s summers become hotter due to our warming climate, keeping cool is more difficult and can be rather expensive, forcing people indoors where they perch themselves in front of the air conditioner.
The methodology underpinning SA Water’s trial at Adelaide Airport is easily transferable to all open spaces in urban areas, creating opportunities to improve the liveability of cities around the world.
“While at a large scale, the concept trialled at the airport can also apply in urban environments like backyards and local parks to help reduce the effect of our warming climate,” Mr Ingleton said.
“By applying the smart irrigation principles we have developed to maintain healthy lawns and vegetation at parks and playgrounds, we can easily show the positive impact on creating cool public spaces people can enjoy in hot temperatures.
“Earlier this year, we launched a new program with 19 South Australian councils which saw more than 200 air temperature sensors installed in the urban environment, helping the community track down their coolest local park or playground using real-time data.
“The sensors captured temperature differences of more than five degrees between green irrigated sites and non-irrigated spaces in the same suburb.
“Hot weather usually drives most people to stay inside under the air conditioner, so having more green cool spaces available will encourage families to still be active outdoors and kick a footy in the local park that’s coolest in their suburb.
“As well as community benefits, there are significant advantages for local councils needing to make cost-effective decisions about their irrigation practices, with more diverse and higher volume community activation driving increased value from the water already invested in maintaining green spaces like sporting ovals.
“Dry ground can be just as hot as bitumen and fake grass can be even hotter, so using water efficiently and in a cost-effective method can further reduce the creation of urban heat islands.”
Available at sawater.com.au, the data forms colour coded maps that show how each park stacks up as a cool outdoor space to take the kids to play or maintain daily exercise goals, even when the mercury rises.
SA Water is providing the data to councils to compare irrigation patterns to any temperature reductions achieved, and help make informed decisions on future park upgrades or investments.
Mr Ingleton said a relatively small amount of water could replicate the cooling effect at a domestic level.
“Targeting how water is applied by watering around a window or air conditioning unit, can greatly reduce the air temperature flowing into your house like a natural air conditioner and help reduce your carbon footprint,” Mr Ingleton said.
“We can further incorporate the effect into house and garden design by positioning windows on the south side of a house and growing a lawn or plants below them, reducing the energy required to power an air conditioner, and benefiting from growing a vegetable patch or fruit trees.
“An established green lawn or garden only needs enough water to maintain moisture levels, so that the cooling effect of the watering is felt for several days afterwards.
“South Australians are water savvy and our augmentation of diverse, climate-independent water sources has created the opportunity to use water in an intelligent way, unlocking the natural cooling effect that enables broader economic and environmental outcomes in the face of climate change.”
SA Water is working together with councils to implement a smart irrigation package of smart water meters, soil moisture probes and a commercial irrigation software program, enabling councils to significantly reduce water use while achieving the same cooling outcome from irrigated parks.
By finessing their irrigation program, it ensures councils are watering more efficiently and only using the exact amount required, subsequently making additional water available to increase green open spaces across their jurisdiction.