The Desertification in Australia's Murray-Darling Basin



In the process, the data chosen were annual mean precipitation, annual mean temperature, annual amount of sun, 1992 and 2005 land use, annual mean evaporation, and relative humidity at 3pm. Relative humidity had a choice of 9am and 3pm. The afternoon was chosen because it is the hottest part of the day and will have greater humidity.


The followinng Cartographic Model was created using IDRISI's Macro Modeler. It shows a visual representation of the processes and algorithms that occured prior to the Multi-criteria Evaluation (MCE) analysis. To achieve the steps prior to the MCE analysis, the imported data had to be resampled to achieve the correct sample size. The Australia_Polygon.rst was used as a base for the resampling. Australia_landuse.rst had to be reclassed and assigned to only show particular landuses including: Nature Conservation, Managed Resource Protection, Grazing Modified Pastures, Livestock Grazing, Plantation Forestry, Production Forestry, Cropping, and Other Minimal Uses.



The data prepared was then placed to be weighted in IDRISI's Decision Wizard. The following table shows the constraints and factors used in the MCE analysis.

Data Collection Factors Weight (Out of 1) Reason of Choice
Australia Polygon Constraint 0.5 Wanted to see what how much the basin will shrink with the applied factors.
Evaporation Monotonically Decreasing; Linear 0.13 Areas that have less evaporation are optimal for present water
Precipitation Monotonically Decreasing; Sigmoidal 0.15 Areas that have more precipitation will likely contain water.
Relative Humidity Monotonically Increasing; Linear 0.03 Areas that are more humid show there is moisture in the area. The moisture is a source of body water.
Landuse Monotonically Increasing; Linear 0.07 Land that contains an abundance of vegetation will show proper soil. Soil is able to retain water and indicates there is groundwater.
Temperature Monotonically Increasing; Sigmoidal 0.05 Conditions of Low temperature will be optimal for water to be present. Higher temperatures in Australia are dry.
Amount of Sun out Monotonically Decreasing; J-Shaped 0.07 Areas that do not have a lot of sunshine will mean there is cloud or a form of precipitation in the area. This is optimal for a body of water to be present.



After performing the MCE, the darker colours shown above indicate the areas of the Murray Darling Basin that will exisit with the current factors Australia is currently facing. The area highlighted in purple is what is predicated to be gone in the future if the conditions remain.



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