Extensive flooding during the wet season created a need for an adequate crossing. It was because of this that the town of Fitzroy Crossing was founded. When it floods the Fitzroy River is an awesome sight. In 1935, the Fitzroy got its first bridge - a low level concrete structure, which was built up into a wider structure in 1958. This bridge could be closed for several months at a time during the wet weather and travellers were then forced to use a flying fox, which operated about 200 metres south of the crossing. When a new bridge was erected in 1974, the focus of the town grew away from its original site. The current town of Fitzroy Crossing is one of the fastest growing in the Kimberley region.

Record floods occurred in 1983, 1986 and 2002 [1] with approximately 13 metres of water over the old concrete crossing. The flow rate down the 15 kilometre wide flood plain at Fitzroy Crossing was estimated to be 30,000 cubic metres per second. In flood, it is probably the largest river in Australia.
From the web at; http://en.wikipedia.org/wiki/Fitzroy_River_(Western_Australia)