Porous pavement to harvest city stormwater


A team of researchers at Melbourne’s Monash University is already on the case, reports The Australian (19 July 2006 p27). Academics at the Institute for Sustainable Water Resources have won a $90,000 Australian Research Council linkage grant, for joint university-industry projects, to study the efficacy of porous pavement for city surfaces.

Aussie product: They will study an Australian product, PermaPave. ISWR deputy director Aria Deletic told the HES that low-use areas, such as car parks, residential streets and pedestrian areas, were most suitable.

Already in UK: Porous paving, used widely in Britain, is made in modular blocks laid with gaps in between or as a monolithic, a bound aggregate such as porous asphalt.

Clogging tests: “In Australia, porous pavements are rarely used, mainly due to perceptions that they are prone to clogging,” Dr Deletic said. “Assessing whether clogging is a problem, as well as the treatment efficiency of PermaPave, is the [focus] of our research.”

Acts as litter filter: Rain that falls on impervious surfaces runs into streams, stormwater channels, bays and the ocean, picking up litter and other pollutants. But Dr Deletic said rain that fell on porous surfaces would percolate through to pipes laid underneath for harvesting and treatment. “Only in the case of extremely large storms will it run off the pavement,” she said.

Choices available for harvested water: “While going through porous pavements, water gets treated to some extent. The water then could be either treated further, stored and reused or discharged.”

Urban run-off roughly equivalent to urban use: It was impossible to replace all impervious paving with porous surfaces, Dr Deletic said. A 1999 study showed that the average annual volume of urban stormwater run-off in Australian cities was almost equal to the average annual urban water use.

Minimal stormwater harvesting currently practised in Aust: But harvesting of stormwater was minimal in one of the driest countries. “It is still not widely practised in Australia. Stormwater is particularly neglected; only 8 per cent of rainwater is used,” Dr Deletic said, quoting CSIRO figures from 2003, although in Melbourne, “recycling of waste water is now very high on the agenda”.

Melbourne on the trail of overseas greenfield projects: “Melbourne Water recycles 11.3 per cent of its treated waste water,” Dr Deletic said. Porous paving was “one of the most popular water-sensitive urban drainage measures in retrofit and greenfield developments in the UK, Sweden, Japan and the US”, Dr Deletic said.

The Australian, 19/7/2006, p. 27

Source: Erisk Net  

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