This project has mapped the occurrence of Acid Sulfate Soils (ASS) in the lower Hunter River floodplain using Light Detection and Ranging (LiDAR) data. The map provides information that will assist land management and rehabilitation. In their natural state, these soils are submerged but when exposed or drained, they become oxidised and sulfuric acid is produced. This reduces soil fertility, kills vegetation and reduces fish populations. The identification of the location and extent of potential acid sulfate soils (PASS) is the essential first step in managing this problem.