The Parramatta River is actually an arm of Sydney Harbour, and it is tidal/salt all the way up to a weir in Parramatta Park. In times gone by, it was a polluted disgrace -- we used to take launches up there to kill the marine growths on the hull. Now the fish and the birds are returning . . .
The Parramatta River will be in everybody's gaze in four years' time, because Homebush Bay, where the Sydney Olympics will be held, is an arm of the Parramatta River.