River system modelling

The department has developed and continues to maintain and use models to understand and assess the behaviour of a series of river systems in NSW, including rivers in the Murray Darling Basin. The models are used to help predict the impacts of current and future water management policy on water users and the environment. These models are tools that support policy development and by running a series of scenarios to understand the impacts the optimum solutions can be identified. Outputs from the models also are used to support the environmental and economic assessment of water management options.

Major regulated river systems

The major regulated rivers in NSW are the Border Rivers (jointly managed by New South Wales and Queensland), Gwydir River, Namoi River, Macquarie River, Lachlan River, Murrumbidgee River and the Hunter River.

In 2009 the NSW Government published information on water reliability for NSW river valleys in the Murray-Darling Basin.

Since the 2009 report was published, there has been interest in the data used to generate the reliability plots, particularly with regards to inter-annual variability in water availability. We have now published, in an annual time-series format, the data that was used to generate the summary information in the 2009 report.

Major unregulated river systems

The department has planning models for the Barwon/Darling River, Richmond River, Clarence River, Macleay River and Bemboka River systems. The major processes that are simulated in the planning models include:

  • Flow routing in rivers, and irrigation channels, including branches, loops and tributaries
  • Reservoir operation
  • Irrigation
  • Urban water supply and other consumptive uses
  • Wetland and environmental flow requirements
  • Water use accounting systems
  • Groundwater/surface water interaction.