Australian Farm Dams
Farm dams are the highest greenhouse gas (GHG) emitters of all freshwater ecosystems, producing the equivalent to 385,000 cars each day in Victoria alone. The Australian Government currently lacks the capacity to monitor farm dams due to their small size and remoteness, and hence tackle their GHG footprint. Our team is working to develop satellite tools to monitor Australia’s farm dams and their contributions to greenhouse gas emissions.
Background
Farm dams are artificial ponds that are used in agriculture to secure water for irrigation, stock, and domestic purposes. But their unique properties make them a hotspot for methane (CH4) emissions – a greenhouse gas 34 times more potent than carbon dioxide (CO2).
First, farm dams are rich in nutrients from fertilizer or manure run-off. Second, their shallow nature promotes microbial respiration, (CO2) build-up, and ideal conditions for methanotrophic bacteria. Third, they warm up rapidly, boosting metabolic rates and bacterial accumulation.
We are currently leading interdisciplinary research across IT, Engineering, and Environmental Sciences to develop satellite tools to monitor Australia’s farm dams and their contributions to greenhouse gas emissions. The goal of this project is to explore new management strategies and engage with stakeholders to discuss incentives for greener practices.
AusDams.org
To facilitate sharing information with the Government, scientists, managers, and the local community, we developed AusDams.org: a free interactive portal to visualise the distribution of farm dams and generate statistics for any area of Australia.
AusDams.org
AusDams.org
Greenhouse gas emissions (GHG)
Carbon dioxide (CO2) and methane (CH4) emissions from reservoirs and natural ponds have been well studied, however, the GHG emissions of highly abundant, small‐scale (<0.01 km2) agricultural dams are still unknown. We measured the diffusive CO2 and CH4 flux of 77 small agricultural dams within south‐east Australia. Results showed:
Farm dams had one of the highest emissions per m2 of all freshwater ecosystems.
GHG emissions amounted to 11.12 ± 2.59 g CO2‐equivalent m2/day, a value 3.43 times higher than temperate reservoir emission.
CO2 and CH4 emission are positively correlated with dissolved nitrate concentrations, and significantly higher in livestock rearing farm dams than in cropping farm dams.
By reducing nitrate nutrient levels by 25% - through activities like minimising excess fertilisation and containing animal effluent - we may be able to reduce the emissions of some farm dams by up to half.
Selected Media & Publications
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Malerba ME, Wright N, Macreadie PI (pre-print). A continental-scale assessment of density, size, distribution, and historical trends of Australian farm dams
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Ollivier QR, Maher DT, Pitfield C, Macreadie PI (2019) Winter emissions of CO2, CH4 and N2O from temperate agricultural dams: fluxes, sources and processes. Ecosphere. https://doi.org/10.1002/ecs2.2914
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Ollivier QR, Maher DT, Pitfield C, Macreadie PI (2018) Punching above their weight: Large release of greenhouse gases from small agricultural dams. Global Change Biology. DOI: 10.1111/gcb.14477
- Farm’s dam good place to cut carbon emissions: World-first study (Deakin Media Release, Australia | Nov 2018)
- Farm dams ‘hotspots’ for greenhouse gases, but so are traffic jams (ABC News, Australia | Nov 2018)
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Dam gases equivalent to a car (The Weekly Times, Australia | Nov 2018)
Funding & Program Partners
This work has been led by Dr Martino Malerba from and Dr Quinn Ollivier from Deakin University’s Blue Carbon Lab.
Project partners include Corangamite Catchment Management Authority; Southern Cross University; Australian Govt – Dept. of Industry, Science, Energy and Resources; Govt of Western Australia – Department of Primary Industries and Regional Development, Sustainability and Biosecurity.
Progress
