The Loxton-Noora area is underlain by 3 aquifer systems - the Pliocene Sands water table aquifer, the confined Murray Group limestone and the deepest, the confined Renmark Group aquifer. Both confined aquifers contain groundwater of 20-25 000 mg/L which is flowing westward under low gradients. Discharge by upward leakage also occurs from both confined aquifers. The water table aquifer contains groundwater of over 35 000 mg/L which is flowing in a northwesterly direction under low gradients. Discharge occurs by evaporation on the River Murray floodplain or by seepage into the river. Discharge is supplemented by drainage water from irrigation areas at Loxton and Bookpurnong. Evaporative concentration beneath low-lying groundwater discharge areas in the Noora-Yamba area have resulted in salinities of up to 90 000 mg/L and downward leakage into the underlying confined limestone aquifer due to density effects. Disposal of irrigation drainage water since 1982 in the Noora Disposal Basin has led to localized water table rises of up to 0.5 metres. Regionally, the water table is rising at 1 cm/year probably as a result of land clearance.