Understanding the groundwaters of the Murray-Darling Basin
While groundwater forms 15 to 20 per cent of the current extraction in the Murray-Darling Basin (MDB), its use varies around the Basin, and is of much greater significance in the Darling Basin.
During drier periods, its relative importance becomes greater especially in regional economies.
Outside of major groundwater use areas groundwater is often more saline or difficult to access and for many of these areas there is no groundwater plan or administration.
Better information and tools are required to assess the impacts of groundwater extraction to ensure improved water management.
CSIRO scientists have developed groundwater models for many of the data-rich areas in the Basin.
Most of the groundwater models enable an analysis of the impacts of groundwater extraction on groundwater levels, stream flow, and groundwater movement from saline areas to fresher areas.
The research has focused on developing techniques for measuring groundwater levels and movement such as:
- groundwater and surface water exchanges
- groundwater residence time
- characterisation of aquifers using geophysics and isotopic water tracers.
These techniques have been applied to many areas of the MDB.
CSIRO and consultants Sinclair Knight Merz have also provided technical information to the Murray-Darling Basin Authority which is setting sustainable diversion limits for groundwater and surface water across the whole of the MDB.
The technical information relates to three areas of work:
- the setting of planning boundaries, given that much of the Basin previously had no formal administration units
- recharge risk assessment method applicable to the whole of the Basin which assesses risks to groundwater-dependent ecological assets, baseflow, and the groundwater resource itself
- numerical groundwater modelling for priority areas to enable refined risk assessment.
For more information download the groundwater fact sheet on page eight.