Predicting the spatial and temporal effects of landuse change using the CATSALT modelling framework

A system of water quality targets including salinity benchmarked at the outlet of each major river of the Murray Darling Basin has been adopted (DLWC, 2000; MDBMC, 2001). The CATSALT modelling framework (Tuteja et al., in press; Vaze et al., in press) has been developed to quantify the spatial and temporal effects of landuse changes on water and salt export from a catchment. Water balance is distributed within a catchment by taking into account the effects of topography, landuse and soils and temporal variability of the climate on runoff and recharge. The distributed water balance is then linked with the salt transport to predict salt export from the catchment. Landuse change scenarios are designed to: (a) increase the perennial content of the pastures and crop rotations and (b) increase the current remnant native woody vegetation with additional tree cover. These scenarios are investigated to determine the level of intervention required to develop ameliorative strategies. Implementation of the CATSALT model is demonstrated on the Boorowa River catchment located in the Lachlan Basin, New South Wales. Likely downstream impacts of the reduction in water flow and salt export are also estimated.