Water Management
River systems
The Department of Water and Energy (DWE) has developed and continues to maintain and use models to understand and assess the behaviour of a series of river systems in NSW. The models are used to help predict the impacts of current and future water management policy on the environment and water users across the state. The models are tools that support DWE policy development and by running a series of scenarios to understand the impacts of each the most optimum solutions can be identified. Outputs from the models also are used to support environmental and economic assessment of water management options.
The main river system model used by the Department for water sharing and management is the Integrated Quantity and Quality Model (IQQM). IQQM has been developed to assess the impacts of different management strategies on all water users. The models have been developed to simulate the major hydrological processes in river valleys, along with relevant management rules, and have been calibrated to match observed reservoir levels, diversions and flows over the calibration periods. The models are set up in such a way as to reproduce average long term behaviour of the river system for planning purposes and not specifically to reproduce individual daily flow behaviour in any particular year or forecast any future year.
IQQM models have been developed for most inland river basins and some coastal river valleys. The models can be utilised to obtain a range of information on simulated river system behaviour ranging from average summary statistics to specific event or sequence details. These models are used in NSW water sharing plans, for auditing NSW compliance with the Murray-Darling Ministerial Council Cap, for estimating baseline salinity condition of NSW rivers in the Murray-Darling Basin, together with a range of strategic and operational hydrologic matters.
The impacts of climate variability and climate change have been a particular focus of the department and we have utilised a range of climate and hydrological modelling approaches to help translate estimates of rainfall and evaporation changes from climate change scenarios into impacts on the surface water regimes of river basins across NSW. DWE models also link with Queensland and Murray-Darling Basin Authority models where water management responsibilities overlap.
Major regulated river systems modelled by DWE are:
Border Rivers (jointly managed by New South Wales and Queensland), Gwydir River, Namoi River, Macquarie River, Lachlan River, Murrumbidgee River and the Hunter River.
View the report on Water availability in NSW Murray–Darling Basin regulated rivers (PDF 656 KB). This report provides information on current water reliability for NSW river valleys in the Murray–Darling Basin.
Major unregulated river systems modelled by DWE are:
Barwon/Darling River, Richmond River, Clarence River, Macleay River and Bemboka River.
The major processes that are simulated 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.