Biophysical modelling of catchment-scale surface water and groundwater response to land-use change Original Research Article

The effect of land-use change on salt and water-balances of catchments in Australia has been significant. Impacts of these changes are often masked by large time lags between the changes and their subsequent expression. Successful management relies on information that allows these changes to be understood and predicted. In the absence of detailed hydrogeological and hydrographic data, a simple approach is required. A logistic function model is introduced, which weights changes in recharge to changes in discharge according to a characteristic time-scale and a rate of change. This response function approach is used to estimate the time lags for individual groundwater flow systems (GFS), which can be aggregated to estimate whole catchment behaviour. Using this model, the predicted future effect of a range of afforestation strategies on catchment salt load has been simulated for sub-catchments of the mid-Macquarie (New South Wales, Australia).