Evaluation of sediment transport in the lower part of the Fitzroy River, Queensland

Comprehensive sediment sampling carried out by the Queensland Department of Natural Resources and Mines (DNRM) at the Laurel Banks site located about 76 km upstream of the Fitzroy River mouth during four flood events in the period 1994-1999 allowed the evaluation of 14 different sediment transport formulae. The bed material load was accurately predicted by the formula of Bagnold and by the formula of Pacheco-Ceballos. Finally the authors have developed a sediment transport formula best suited to the Fitzroy River conditions. By applying acceptable formulae to hydrograph data for 35 years it was confirmed that approximately 20 million tons of sediment might be eroded from the catchment during the most severe flood events. The mean annual total sediment discharge has been computed to be more than 5 million tons, and the mean bed material discharge sums up to about 260,000 tons.