Catchment run-off
The Reef receives run-off from 35 major catchments that drain 424,000 square kilometres of coastal Queensland. Most sediment entering the Great Barrier Reef comes from catchments in major pastoral areas such as the Burdekin, Herbert and Fitzroy rivers.
The catchments that deliver water in the Great Barrier Reef can be divided into:
coastal catchments that provide a continuous flow of freshwater to the Reef from small catchments supporting intensive farming, for example Tully River and Pioneers River
large catchments that drain large inland grazing areas and ten