A combined groundwater and solute transport model (MODFLOW and MT3D) was constructed of the Loxton Irrigation Area to determine the future impacts on groundwater levels and salt loads to the river and floodplain for a range of local irrigation practice management options. This six layer model generally confirmed the groundwater flow rates estimated by the previous PIRSA two layer model. The solute transport modelling results for the latest model run period 1947 to 1997 have been combined with flow data to produce estimates of salt loads to the river, which confirm a lag of 13 years between the beginning of maximum irrigation applications and the resultant maximum salt loads to the river. Salt loads for the various management options have also been computed: these are presented with the reservation that the floodplain component of salt load is likely to be in error until a model with more realistic initial conditions is established. Serious reservations now exist regarding the value of predictions of groundwater flow in the floodplains estimated by either of the PIRSA models, due to non-consideration of flooding events in the setting up of initial conditions. This is particularly true in the case of solute transport modelling, which requires either the input of results from field investigation on the floodplains, or else the running of a transient model incorporating several flood events, in order to establish meaningful initial conditions.