High country water run-off to fall

High country water run-off to fall

2 December 2008

published by www.weeklytimesnow.com.au

Australia — RUN-OFF into water catchments from the high country will plummet by a massive 30 per cent in the coming decades.

Less rainfall, increased evaporation and more bushfires are the triggers and will leave Melbourne, Canberra and Adelaide in dire straits for water, along with farmers and communities who rely on the catchments.

That was the message last week from Prof Mark Adams, dean of theFaculty of Agriculture, Food and Natural Resources at the University of Sydney.

Speaking at a bushfire meeting at Omeo last week, Prof Adams said the estimate of 30 per cent was based on extensive research and modelling over many years in the high country.

He said the research showed plant transpiration – the water plants take from the soil and send back to the atmosphere – was the single most important component of the catchment water balance. Severe bushfires completely changed that component.

“The fires of 2002-03 and 2006-07 – we haven’t even begun to see the effects of those in reduced run-off and water yield, but they will, over coming decades, have a very severe effect,” Prof Adams said.

Questioned about Gippsland’s Macalister Irrigation District, which had its catchment devastated by fire in 2006-07, Prof Adams said a massive reduction in water was inevitable.

“Given what I know of the area burnt, we could easily be seeing a 20 per cent reduction in the Macalister and it could go as high as 30 per cent,” he said.

Prof Adams said that rather than spend billions of dollars on desalination plants and the distribution of water in the Murray-Darling, money should be spent on improved forest management and ensuring every drop of water got into catchments.

A senior researcher at Monash University’s School of Geography and Environmental Science, David Packham, said at least 10 per cent of the state needed to be burnt in prescribed burns each year, but not even half of that was achieved.

Department of Sustainability and Environment fire officer David Tainsh said while all parties agreed more fuel reduction burning was necessary, public safety, occupational health and safety concerns and litigation were a hindrance.

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