Lake Victoria is an off-river water storage in western N.S.W. and the Rufus River is its outfall channel to the River Murray. Very saline groundwater seeps into the Rufus River and hence enters the River Murray system. A groundwater pumping scheme is being designed to reduce the salt input to the Rufus River. To calibrate the computer model being used for this design an aquifer test was conducted to obtain a value of Transmissivity and Storage Coefficient for the Loxton Sands aquifer. A pump well and 11 piezometers were installed for the testing. The aquifer is a semi-confined (leaky) aquifer with the Rufus River acting as a recharge boundary. Appropriate steady state and non-steady state analyses of the pumping test data yield an average value of Transmissivity of 100 m /day/m and Storage Coefficient of 5 x 10 , but higher values recorded in several of the shallower piezometers indicate that variations in aquifer parameters occur. The average salinity of the pumped groundwater was 59 000 milligrams perlitre with the NaCl ion-pair dominant.