South Australian investigations have concentrated on defining the nature of the Tertiary limestone aquifer and determining aquifer recharge rates in Zones 3A-7A, to enable a reassessment of groundwater resources for Zones 2A-8A. An examination of the significance of localised recharge from drainage wells, swamps and runaway holes is continuing. Victorian investigations resulted in the establishment of a network of bores to monitor water quality and aquifer pressures. Eight wells were used for aquifer tests to determine the bulk hydraulic conductivity of the limestone aquifer and coefficients of storage. Other studies are assessing the distribution of both diffuse and point recharge within the Mallee and Wimmera regions.