The review determined that only a small proportion of the sediment that has been eroded from the watershed makes it to the mid and outer reefs. The sediment transported > 1 km offshore is generally the clay to fine silt (< 4-16 渭m) fraction, yet there is considerable potential for other terrestrially derived sediment fractions (< 63 渭m) to be stored in the near-shore zone and remobilised during wind and tide driven re-suspension. The specific source of the fine clay sediments is still under investigation; however, the Bowen, Upper Burdekin and Lower Burdekin sub-watersheds appear to be the dominant source of the clay and fine silt fractions. Sub-surface erosion is the dominant process responsible for the fine sediment exported from these watersheds in recent times, although further work on the particle size of this material is required. Maintaining average minimum ground cover > 75% will likely be required to reduce runoff and prevent sub-soil erosion; however, it is not known whether ground cover management alone will reduce sediment supply to ecologically acceptable levels.