Scientists are warning the water industry about risks posed by a changing climate.

CSIRO’s Goyder Institute for Water Research says climate change modelling for South Australia paints a bleak picture for water supplies.

Models for the Mount Bold reservoir – SA’s largest water catchment – shows a big reduction in inflow is on the way. 

Goyder Institute director Michele Akeroyd says the Onkaparinga catchment, which feeds Mount Bold reservoir, will be affected by hotter weather and less rainfall predicted for the end of the century.

“The worst-case scenario indicates a halving of inflows into the Onkaparinga catchment over the century. That is against the high emissions scenario, and if you look at the IPCC (Intergovernmental Panel on Climate Change) data, we are actually tracking on that scenario at the moment,” she said.

Even if carbon emissions were maintained at current levels, the inflow to Mount Bold reservoir will still drop by one-third by the end of the century.

South Australia’s Goyder Line - a rainfall boundary beyond which land is deemed unsuitable for agriculture – is set to move further south.

Meanwhile, Victorian farmers’ group Agribusiness Gippsland has warned about similar CSIRO predictions of rising sea levels, hotter days and 30 per cent less rainfall in coming decades.

Spokesperson Sue Webster told the ABC this week that farmers are already well ahead of the Federal Government in their attitudes to changing weather patterns.

“We know that there are now pasture breeds coming through for water use efficiency, we actually know that there are farm stock that are coming through the livestock realm because they've got better use efficiency in their own systems,” she said.

The group is pushing for measures like extending the Macalister Irrigation District and building the Tinamba Phase Two Project to help farmers adapt.

“This is really important, we've got to start using the technology smarts at hand to overcome the problems that we're going to be facing with climate change,” Ms Webster said.