Rare native birds have joined well-established birdlife at the Urrbrae Wetland, little more than a year after it was created in the heart of suburban Adelaide.

A group of black-tailed native hens - a cock and three hens - has taken up temporary residence even before the 4.5 hectare wetland has properly established its vegetation. The highly nomadic, jungle fowl-like birds are normally found among reed margins and lignum swamps of the River Murray -- not in metropolitan Australia.

The success in attracting rare birdlife, as well as 21 other bird species, to Urrbrae coincides with plans to harvest wetland-filtered stormwater for use by surrounding learning institutions such as Urrbrae Agricultural High School.

Initial drilling and analysis of ground water by Mines & Energy SA indicates that some 30,000 kilolitres of recyclable water may be available each year to irrigate ovals and recreation areas.

"We'd have achieved an even better result if we hadn't come across lignite", says CSIRO principal research engineer Dr Peter Dillon.

"The Urrbrae Wetland sits above an old swamp that generated the lignite,which is a precursor to coal. The compressed and rotted vegetation which forms lignite is interspersed with sand and clogs the screens of the well - a bit like tea leaves blocking a strainer," says Dr Dillon.

"We used the best technique available, but the first rule of drilling is never to expect anything to go smoothly". Further testing, by pulsing with increased water pressure, to break up and flush out lignite in the vicinity of the well, may be carried out to try to maximise the amount of recyclable water. As Dr Dillon puts it: "Quantity is the primary problem, not the quality."

It is ultimately proposed that during winter months stormwater from the Urrbrae Wetland will be injected down a well for storage in the deep aquifer and recovered in summer for irrigation.

CSIRO's partners in the recycling plan are the University of Adelaide, SARDI, Urrbrae and Unley high schools, the City of Mitcham and the Patawalonga Catchment Board which believes the wetland will help clean-up the Patawalonga system.

The 375 hectare catchment area is bordered by Brown Hill Creek, Springfield, the Waite Research Institute and Cross Road and its runoff enters the Urrbrae Wetland at two separate inlets fitted with trash racks to remove large debris and silt.

Wetland co-ordinator, Dr Allin Hodson, has cautioned the public not to overestimate the Urrbrae scheme's capacity to clean up the environment.

"There still exists among some people the mentality that once they tip something down the drain, it's gone - it's not their problem," says Dr Hodson. "The fact is that liquid waste which goes down the drains passes straight through the trash racks and can destroy the life of the wetland."

Dr Hodson says the Urrbrae Wetland has already become a valuable and popular educational facility, with more than a thousand students having visited the Learning Centre, and will become even more so as the project matures.

More information:
Dr Peter Dillon, CSIRO Land & Water (08) 8303 8714 (o) (08) 8271 2775 (h)
Dr Allin Hodson, Urrbrae Agricultural High School (08) 8272 6955 (o) mob. 018 855 254