Surface & groundwater models overview

Surface water models

The surface water models used for water sharing and management use either the Integrated Quantity and Quality Model (IQQM) software, or eWater‘s Source software. IQQM and Source planning models were developed to assess the impacts of different management strategies on all water users, including the river environment, and to simulate the major hydrological processes in river valleys along with relevant management rules. These models were calibrated to match reservoir levels, diversions and flows over the calibration periods. The models are set up in such a way as to reproduce the 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 to forecast any future year.

Planning models weredeveloped for most inland river basins and some coastal river valleys. The models can be used 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 different water management areas such as:

  • Water Resource and Water Sharing Plans (PDF, 479.75 KB)
  • Auditing NSW compliance with the Murray-Darling Ministerial Council Cap, and the future the sustainable diversion limit
  • Estimating the baseline salinity condition of NSW rivers in the Murray-Darling Basin
  • Strategic and operational hydrologic matters.

Groundwater models

The groundwater models used for water sharing and management use versions of MODFLOW, developed by the United States Geological Survey (USGS). Groundwater planning models were developed to enable simulation and predictions based on water sources, diversions and losses in groundwater systems. Responses to changes in these sources, diversions and losses are modelled as changes in groundwater levels and groundwater quality in space and time.

Groundwater models were developed for major inland alluviums and selected coastal aquifers. The models are used to investigate, audit and derive sustainable yield estimates for the state's groundwater systems.

These models are used in different water management areas such as: