Three groundwater observation wells have been drilled at locations north-west of Murray Bridge to determine the effect of increased stream flows down the Rocky Gully and Preamimma Creeks. Rocky Gully Creek will be capable of accepting about 10 000 m /day and any further volumes will continue as surface flow, directly to the River Murray. Subsurface flow would displace saline groundwater, causing an increase in River Murray salinity of about 150 tonnes of salt/day in the initial 60 years. Consequently, alternative methods for disposal of runoff should be investigated. The Murray Bridge Irrigation Area will riot be affected by increased flows down Rocky Gully Creek, except that increased pumping will be necessary from the saline drainage channel. Relatively minor increases in flow are expected down Preamimma Creek, and this will result in a negligible increase in River Murray salinity.