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.
We are seeking PhD candidates, interns and research assistants to join an ARC Discovery Early Career Research Award on this project! See our Opportunities page to learn more.
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.
Remote sensing
Farm dams are hard to monitor: too many, too small, and located in remote private properties. Improving current satellite methods is a necessary step to understanding the role of farm dams in the environment, with important economic and social benefits. The Blue Carbon Lab leads collaborations with Dept. Primary Industries and Regional Development, Dept. of Environment and Energy, and Deakin School of IT and Engineering to develop new tools to detect and monitor small water reservoirs. For example, we can use high-definition satellite images and deep-learning convolutional neural networks to analyse farm dam water surface, maximum surface area, surrounding catchment area, and vegetation type and cover (ref1, ref2).
We aim to maintain our database on an interactive website to engage farmers, stakeholders, and the general community on the importance of managing farm dams.
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 publications
- Malerba, M. E., Lindenmayer, D. B., Scheele, B. C., Waryszak, P., Yilmaz, I. N., Schuster, L., & Macreadie, P. I. (2022). Fencing farm dams to exclude livestock halves methane emissions and improves water quality. Global Change Biology. https://doi.org/10.1111/gcb.16237
- Malerba, M.E.; Wright, N.; Macreadie, P.I. Australian farm dams are becoming less reliable water sources under climate change. Science of the Total Environment 2022, vol 829. https://doi.org/10.1016/j.scitotenv.2022.154360
- Malerba, M.E.; Wright, N.; Macreadie, P.I. A Continental-Scale Assessment of Density, Size, Distribution and Historical Trends of Farm Dams Using Deep Learning Convolutional Neural Networks. Remote Sens. 2021, 13, 319. https://doi.org/10.3390/rs13020319
- Ollivier QR, Maher DT, Pitfield C, Macreadie PI. Winter emissions of CO2, CH4 and N2O from temperate agricultural dams: fluxes, sources and processes. Ecosphere 2019. https://doi.org/10.1002/ecs2.2914
- Ollivier QR, Maher DT, Pitfield C, Macreadie PI. Punching above their weight: Large release of greenhouse gases from small agricultural dams. Global Change Biology 2018. DOI: 10.1111/gcb.14477
Selected Media and Outreach
- Healthy dams mean healthy farms (Country News, September 2022)
- Webinar for ACT NRM Landcare & Waterwatch on managing farm dams to reduce carbon emissions, improving biodiversity & water security (Youtube, September 2022)
- Presentation at the South Gippsland Landcare Network on reducing greenhouse gas emissions from farm dams (Vimeo, June 2022)
- Aussie farm dams help cut greenhouse gases (7 News, Australia | January 2022)
- Presentation at Zero Emissions Farming Conference 2021 (Youtube | November 2021)
- Presentation for Deakin Centre for Integrative Ecology on Farm Dams (Youtube | November 2021)
- Farm dams hold secret of carbon capture (The Weekly Times, Australia | December 2021)
- 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)
- Dam gases equivalent to a car (The Weekly Times, Australia | Nov 2018)
Funding & Program Partners
This program is run by Dr Martino Malerba from Deakin University’s Blue Carbon Lab.
The Australian Research Council funded this project through a DECRA fellowship awarded to Dr Malerba. Other 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; Australian National University and Sustainable Farms.
