Turning rain into food – the benefits and performance of vegetable raingardens
(2011 – current)
Runoff from impervious surfaces such as roofs is a primary contributor to flooding and water quality problems in urban catchments. Raingardens (aka biofilters) are systems engineered to both filter pollutants from urban runoff and regulate runoff rates, with significant benefits for the condition of urban waterways. Raingardens also have considerable value as rainwater harvesting devices, reducing the demand for treated water. As such, the construction of raingardens has been actively promoted in several of the world’s cities, including Melbourne, where Melbourne Water has introduced a 10,000 Raingardens initiative.
With a view to further expanding the functionality and public acceptance of raingardens, we are investigating whether the functions of a standard raingarden can be combined with those of a traditional vegetable garden, in a “vegetable raingarden”.
This project aims to test and demonstrate the idea of a vegetable raingarden in relation to (i) its impacts on the quantity and quality of stormwater runoff; (ii) the growth and productivity of its vegetables; and (iii) the risk of contamination of the soil and vegetables. Four experimental gardens have been built at the University of Melbourne’s Burnley campus, and monitoring of these gardens will be supplemented by laboratory and greenhouse based experiments.
This project supports two postgraduate research projects. The first, undertaken by Minna Tom (Roof-harvested rainwater irrigation of vegetables – is there a risk to human health?) aims to investigate whether microbiological and chemical contaminant concentrations in vegetables irrigated with roof-harvested rainwater are significantly greater than vegetables irrigated with potable mains water. It will also assess whether any contamination present poses a short or long term risk to human health. The second, undertaken by Paul Richards from the University of Melbourne, investigates the hydrology of a vegetable raingarden and the implications for vegetable growth.
Dr David McCarthy, Prof Tim Fletcher (University of Melbourne), Dr Claire Farrell (University of Melbourne), Dr Nick Williams (University of Melbourne), Peter Poelsma, Paul Richards (University of Melbourne) and Minna Tom.
Associated Postgraduate Projects:
- Roof-harvested rainwater irrigation of vegetables – is there a risk to human health? (Masters) – Minna Tom
- Hydrology of a vegetable raingarden and implications for vegetable growth (Masters – University of Melbourne) – Paul Richards