The Department of Defence proposes to undertake maintenance dredging of accumulated sediments alongside its marine infrastructure on the eastern side of Garden Island, in Cockburn Sound, to return naval waters to navigable depths. Approximately 1,900 cubic metres (m3) of material is to be excavated from four locations in Careening Bay and 5,480m3 of material from the Armaments Wharf in Sulphur Bay.
The proposed dredging method is to use a long reach excavator with a bucket fitted with a cutter suction pump connected to floating pipeline. This will allow dredged material to be discharged direct to the seafloor via downpipe thereby minimising generation of turbidity in the water column. The material to be dredged is predominantly fine sand and has been tested by the proponent and considered suitable for unconfined disposal into deeper Naval waters within Cockburn Sound.