The NCCARF Water Resources and Freshwater Biodiversity Network has released its 2011 'report card', entitled Climate Change Impacts and Adaptation Strategies for Western Australian Aquatic Ecosystems.
“This report card is a wonderful accomplishment, representing input from about 150 people involved in wetland, rivers, estuaries or subterranean ecosystems research, management and conservation across the State,” says Network WA Regional Leader, Dr Jane Chambers from Murdoch University.
“From the beginnings in July last year at the symposium Climate Change and Western Australian Aquatic Ecosystems, to now, we have accumulated an enormous amount of information.”
While the Report Card looks at conditions, predictions and knowledge gaps across the State, its focus is on the South West, one of the most vulnerable regions in the world to the effects of climate change.
Highlighted is rainfall, which has reduced by 50mm per decade since 1970. Researchers predict further losses of between two and 14 per cent by 2030.
This is likely to impact stream flow into dams by anywhere between ten and 42 per cent, exacerbating the 50 per cent drop in flow levels from 1975 to 2010.
Perth’s most vital source for drinking water, the Gnangara Mound is pegged as a cause for concern. Its level declined by six metres from 1979 to 2005, four metres of which is attributed to reduced rainfall.
The Report Card predicts extraction yields for groundwater in the South West to decline by a further third to half by 2030.
This spells trouble for the Gnangara Mound, as water levels in more than half of its 30 monitoring wells fell below acceptable levels according to an as-yet unreleased 2009 State Government report.
But while fresh water declines, rising ocean levels will also impact waterways.
In Fremantle, sea levels have risen by an average of 5mm per year over the past decade as compared to an average of 1.54mm per year over the previous 100 years.
Median future climate scenarios predict a 100mm increase from 1990 to 2030.
The Report Card also outlines a wealth of adaptation options. While these include the obvious steps of evaluating and prioritising areas for conservation, they also include strategies such as retrofitting existing drainage structures to supplement river flows, promoting connectivity between waterways (e.g. fish ladders), revegetation and translocation.
As for Northern WA and the rest of the State, the Report Card recommends further data collection and modelling.
For more information http://www.nccarf.edu.au/water/node/29
