Growing food and stopping floods with rain gardens

Posted on October 4, 2017

Drainage pipes flowing directly from bathroom to river. Photo: Hadi Susilo Arifin

Small urban ‘rain gardens’ are popping up all around Australia and Indonesia to keep waterways free from pollutants, stop flooding and erosion, and to grow food.

Although they may look similar to a normal garden, beneath the surface, rain gardens are a sandwich of layers of sand, gravel, roots and microbes through which polluted water passes and clean water exits, which can then be used for irrigation or washing.

“Rain gardens not only keep our precious waterways free from contamination, they are beautiful to look at, provide habitat to local wildlife, use very minimal energy and are easy-to-maintain,” says Associate Professor David McCarthy, from Monash University’s Environmental and Public Health Microbiology Laboratory.

David, supported by The Australia-Indonesia Centre, is working with Professor Hadi Susilo Arifin of Bogor Agricultural University to bring rain garden technologies to communities in Bogor, Indonesia.

Known as Indonesia’s rainy city, Bogor receives 3,000 mm of rain per year. Colonial era irrigation channels transport runoff to rice fields that encircled the small city. But with houses now replacing most of the city’s agriculture, the runoff has no option but to run downstream and flood nearby metropolis Jakarta.

“Our water infrastructure was built for irrigation, not drainage,” Hadi says.

“So we are looking at creative ways to irrigate urban areas.”

Hadi and his team are working with three communities in Bogor to adapt Melbourne’s rain garden technology. He also hopes to educate villagers about water hygiene.

“Most communities in Indonesia have low levels of environmental education so they treat rivers as garbage bins. Perhaps when they are filtering water themselves and using it to grow cash crops that make them income, they will appreciate clean water more,” Hadi says.

“As our water is more polluted than Melbourne, this will affect how we design the filtration system and what plant species are chosen as filters.”

He also hopes that villagers will self-organise to use the better quality water in creative ways.

“My dream is to see zero runoff because the community and government are seeing water as part of the urban landscape and are using it sensitively.”