Groundwater discharge is associated with salinity and pollution problems. The widespread presence of millions of saline lakes in North America, Africa and Australia, shows that across the geological record, most salinity and desertification problems have been caused by saline groundwater discharge. In recent times, dryland salinity has spread widely in southern Australia, resulting in the loss of more than 50% of the fresh streams in Western Australia and causing major salinity problems in the Murray River in South Australia.