Mapping and modelling
A range of data sets and mapping products have been produced that are relevant to salinity management, including maps of:
- Native vegetation
- Land use
- Recharge and run-off
- Potential discharge areas
- Salt outbreak areas, and
- Groundwater flow systems
These maps are derived using direct field observations and data modelling techniques.
The vegetation maps and accompanying scientific reports are available on-line. Other information can be accessed from the Community Access to Natural Resources Information (CANRI) website, which aims to bring together key environmental information from NSW Government agencies and other organisations.
Modelling is used to fill information gaps where data is limited or to add value to data by combining it in ways that represent processes that are otherwise not directly mappable. For example, it is not possible to directly map the extent of salinisation in 2050, but by using a model that represents the processes of dryland salinisation, it is possible to extrapolate from existing spatial data to make predictions about future condition.
To manage salinity in a catchment we need to know:
- Where and how much salt is stored in the landscape,
- How salt and water moves in the landscape,
- How the geology and structure of the landscape contributes to the problem,
- What affects the rate of movement of salt, and
- How changing something in one location affects the rest of the catchment or basin.
Computer based modelling tools also support natural resource management by enabling different management options to be explored and evaluated, or to allow data to be extrapolated in time and space when limited data is available.
A suite of models make it possible to:
- evaluate where salinity is currently occurring in the landscape and where it might occur in the future,
- predict the impacts of land use changes on run-off, salt loads and salinities from catchments to streams, and
- evaluate the contributions of these changes to meeting within valley and end-of-valley targets.
The models provide information needed by Catchment Management Authorities to develop target-based management strategies. They provide practical scientific and technical support on biophysical aspects of salinity management for property and catchment planning. This includes providing scientific and technical support to the setting, reviewing and auditing of end-of-valley and within valley targets, and to the development and accreditation of Catchment Action Plans, and associated market-based solutions to salinity.
The models will collectively provide information at the three scales relevant to implementing salinity management in NSW, which are:
- The property or farm scale,
- The scale of catchments up to about 2,000 km2 in area, and
- The river basin scale.
At the property scale the main modelling tool being adopted is PERFECT, which is a well established tool for modelling recharge and the impacts of vegetation changes on recharge, at a given location.
The catchment scale-modelling tool is CATSALT. CATSALT is the only modelling tool currently available in Australia that can predict the effects of land-use changes on streamflows, in-stream salinities and salt loads at catchment scale. It is an "umbrella" model in that it uses outputs from other models such as FLAG and SMAR to produce its results.
Results from CATSALT are then used as input to other models, such as IQQM, to evaluate cumulative impacts from multiple catchments and contributions to meeting within-valley and end-of-valley targets. IQQM was developed to manage water access and water sharing arrangements within catchments, but is currently being further developed to estimate the impacts of land use changes on end-of-valley targets.
Collaborative links have been formed with other agencies and organisations such as the CRC for Catchment Hydrology and CSIRO to improve integration and communication between models, as well as expand the scope of the models. The testing and validation of DNR models has involved peer review by scientists from other organisations and international research institutes.
References and resources
- Dr Mark Littleboy, Professor Rob Vertessy and Dr Paul Lawrence. An overview of modelling techniques and decision support systems and their application for managing salinity in Australia.
- N. Herron and P. Peterson. A Simplified GIS-Based Approach to Prioritise Salinity Investment at the Property-Scale.
- M. Littleboy, N. Herron and P. Barnett. Applying unsaturated zone modelling to develop recharge maps for the Murray-Darling Basin in New South Wales, Australia.
- Narendra Kumar Tuteja, Geoffrey Beale , Warrick Dawes, Jai Vaze, Brian Murphy, Paul Barnett, Aleksandra Rancic, Ray Evans, Guy Geeves, Daud W. Rassam and Michelle Miller. Predicting the effects of landuse change on water and salt balance - a case study of a catchment affected by dryland salinity in NSW, Australia.
- Jai Vaze, Paul Barnett, Geoffrey Beale, Warrick Dawes, Ray Evans, Narendra Kumar Tuteja, Brian Murphy, Guy Geeves, Michelle Miller. Modeling the effects of landuse change on water and salt delivery from a catchment affected by dryland salinity.
- Brian Murphy, Guy Geeves, Michelle Miller Greg Summerell, Paul Southwell and Madeleine Rankina. The Application of Pedotransfer Functions with Existing Soil Maps to Predict Soil Hydraulic Properties for Catchment-scale Hydrologic and Salinity Modelling.
- D. Rassam and M. Littleboy. Identifying the Lateral Component of Drainage Flux in Hill Slopes.
- G.K. Summerell, J. Vaze, N.K. Tuteja, R.B. Grayson, and T.I. Dowling. Development of an objective terrain analysis based method for delineating the major landforms of catchments.
- N.K. Tuteja, J. Vaze, G.T.H. Beale, G. Summerell and M.Miller. Spatial disaggregation of catchment scale fluxes.
- J. Vaze, G.T.H. Beale, Paul Barnett and N.K. Tuteja. Predicting the spatial and temporal effects of landuse change using the CATSALT modelling framework.
Page last updated: 26 February 2011