Potential dangers of serious saltwater intrusion exist for any unconfined, coastal aquifer from which significant volumes of water are extracted. Under quasi-steady conditions, the extent of saltwater intrusion can be estimated satisfactorily from regular field measurements of water table levels and the Ghyben-Herzberg approximation.
If water table levels fall temporarily, e.g. during a drought, this approach yields an overestimate of the extent of saltwater intrusion and an improved method is needed if realistic estimates are to be made. Such conditions occurred in the Bribie Island aquifer in the summer of 1983. This report describes a subsequent study into the dynamic response of the salt-fresh interface for that aquifer.