AERIAL photographs are purported to show sediment and plumes coming from a North Fremantle basin to where port dredging waste is being pumped.
Other Fremantle Port Authority (FPA) images are said to show a Swan River mouth two weeks ago reached beyond predictions on which the public could comment last year.
Swanbourne Coastal Alliance spokesman Jean-Paul Orsini said the Rous Head photographs indicated plume material could spread potential contaminants, and rubble may wash up on Port Beach, ruining summer swimming.
He said the January 29 pictures, taken in easterly winds, show a plume or disturbed sediment about halfway along the dredge’s partially floating pipe pumping dredgings into the 27ha Rous Head basin that is part of the $250m project to deepen the port for 16.5m-draft ships,
Another broad plume supposedly emerges from about 300m of the basin’s west seawall, after Transport Minister Simon O’Brien told State Parliament in October a seawall liner would prevent fine particles escaping.
Mr Orsini said other photographs taken the same day show a river mouth plume reaching about 5km offshore, over sensitive seagrass beds.
Thirteen months ago, the Sinclair Knight Mertz-authored Public Environmental Review, for public comment on the proposed dredging, had said the plumes would not extend far along the coast and would be in the immediate area off Rous Head.
Last week, an FPA spokeswoman said discoloured water near the pipe was from manoeuvring the dredge and a support vessel in shallow water to connect the floating pipeline.
Local plumes, similar to those during the seawall’s first stage construction, are expected from during current work raising the wall’s height to the existing North Mole’s level, she said.
“Water quality monitoring has occurred inside the reclamation area, and outside the seawall, and the results confirm that potential contaminants remain well below the applicable environmental and health guidelines at both locations,” the spokeswoman said.
The plumes were within Environmental Impact Assessment modelling for the project’s approval process, she said.
A Federal Environment Department spokeswoman said a sea dumping permit was still being assessed and there was no deadline.
Any plume’s seabed material were to be investigated by State-based authorities as national laws were triggered only by a likely impact on nationally protected species, she said.