The United States Geological Survey software package MODFLOW was used to construct a three-layer predictive simulation model of the groundwater flow underlying Emu Springs, an area in the southern Mallee region of South Australia near Tintinara. The purpose of the model was to assess the hydraulic impacts of extracting a hitherto unprecedented volume of groundwater to irrigate a proposed 1600 hectare plantation of olive trees. Based on assumed aquifer parameters and recharge rates, the results indicate that there is likely to be an impact on existing potentiometric heads in the area, subject to whatever will be the respective levels of use from each of these aquifers. This may impact on other groundwater users in the area of drawdown for each aquifer. Pumping of groundwater from the proposed 16 new wells to be completed in the unconfined aquifer shows a long-term decline in heads. A new state of equilibrium will not be attained until 25 years after the commencement of extraction. For the case where the irrigation extractions will come from both the unconfined and confined aquifers, the likely cone of drawdown in the confined aquifer is spatially more extensive than that for the unconfined aquifer. The likely cone of drawdown in the unconfined aquifer is reduced under such an extraction scenario. It is possible that some adverse groundwater quality impacts may also be experienced, particularly in the case of the unconfined aquifer, due to increased salt accessions to the aquifer resulting from the irrigation activity. This aspect requires further investigation, and is of particular relevance to the developer if he is to maintain the groundwater quality at a suitable level for sustaining the irrigation enterprise in the long term.