The benefits of carbon-friendly stormwater systems

Wednesday, 5 September 2018

Engineers at Griffith University have shown that carbon capture is a significant phase in the carbon footprint life cycle of vegetated stormwater systems, which can bring multiple benefits to the urban environment.

Led by civil and environmental engineering PhD candidate Emad Kavehei, the research involved Dr Graham Jenkins from the School of Engineering and Built Environment and Dr Fernanda Adame of the Australian Rivers Institute, both at Griffith, along with Professor Charles Lemckert from the University of Canberra’s Faculty of Science and Technology.

Much of what engineers and decision-makers understand about the carbon footprint is limited to the four phases of the life cycle assessment method, according to the research team. This includes the material production, construction, operation and maintenance, plus the end-of-life phases.

The researchers studied a wide range of vegetation-based stormwater infrastructure including green roofs, bio-retention basins, vegetated swales, rain gardens and stormwater ponds. Their findings showed that rain gardens and bio-retention systems had the potential to mitigate more than 70% of their total carbon footprint in their 30-year lifetime. 

The results of their research have been published in Renewable & Sustainable Energy Reviews.

“There are already many papers that talk about the benefits of stormwater basins that are vegetated, but in these systems there are also carbon sequestration potentials, and the studies have not examined these benefits and these potentials together,” Kavehei said.

He explained that the results are valuable for researchers, designers and policymakers when considering the carbon implications of any potential green stormwater infrastructure, and that they provide materials to estimate the net carbon footprint for vegetated stormwater basins. 

While a vegetated system requires more maintenance than a constructed pipeline does, according to Kavehei, vegetated systems have the “potential to sequester and reduce the carbon emissions and footprint through the whole-service years-of-life cycle” in stormwater infrastructure. 

“What is important for policymakers and councils is that they can claim these basins are carbon-friendly,” he explained.

“If they know they can build more of these sites they can claim for carbon reductions, so it would be win-win. They would have a system that treats stormwater and adds environmental benefits to Australia’s goal of reducing carbon emissions.” 

And from an ecological view, Kavehei emphasised, having more of these systems would add to the biodiversity of neighbourhoods - so having more vegetated stormwater systems would increase birds and wildlife in these areas.

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