Thanks for the link.
The good news is I wasn't going potty; there is no Gladstone River!
The bad news is Peel Holdings.
It seems they are going to keep the dredgers busy; checking on a chart just now I saw that a line joining the entrance to the Gladstone Lock to the corner of the Royal Seaforth riverside wall will leave a bottom of between 2m and 6m until some distance from the wall where it drops to 12m, although I suppose it is possible that putting a wall there will cause the river to scour the bottom itself as the water goes rather quickly through that patch.
Cheers
Kelvin