The annual flow coming down the Darling River has reduced by 70% over the past century, creating water quality issues such as high salinity and algal blooms and critical water shortages.
That was just one of the insights to come out of the Exploring for the Future 2020 Showcase held on Wednesday by Geoscience Australia.
Hydrogeologist Sarah Buckerfield presented research on the Darling River system at the three-day event.
Ms Buckerfield’s surveys of the river, north of Bourke to south of Wilcannia, showed that some areas discharged saline groundwater into the river system, which has consequences for salinity and salt loads.
Other areas near Tilpa, Wilcannia and White Cliffs recharged the river’s groundwater system with fresher water because bedrock made these areas more resistant to saline.
The showcase brings scientists, industry and invested communities together to discuss how Australia’s resources will support a more sustainable Australia, said Federal Minister for Resources and Northern Australia, Madeleine King.
Ms Buckerfield examined what exactly controls the groundwater and surface flow paths, and the distribution of potable water sources in the Darling River.
Scientists attribute the reduction in water flow to extraction, drought, and increases in temperature driven by climate change.
Recent comparative data from the Southern Oscillation Index (SOI), which measures atmospheric pressures, show El Nino and La Nina events influence river flow.
The primary water source flowing down the Darling River is rainfall from the high precipitation catchment areas.
Ms Buckerfield’s research showed that the alluvium areas in the river basin have a shallow fresher surface water system (less saline) and a deeper saline groundwater system.
Ms Buckerfield said the next step in the research is to identify and map the areas along the river basin that discharge salinity into the river system and identify parts of the basin that recharge fresher water into the river.
These insights into the river system’s hydrology will help improve the overall management of potable water along the river system.