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Dredging

What is maintenance dredging?  (download fact sheet)

Maintenance dredging removes sand, silt, mud and rock from underwater channels and berths where it has collected through natural processes such as wind or wave action. Maintenance dredging is required to keep the channel and the harbour at an acceptable depth to allow safe access for commercial, cruise and military ships.

Are are the maintenance dredging works needed in the Port of Townsville?

The Port of Townsville is currently linked to national shipping routes by a 14 kilometre long and 92 metre wide channel in Cleveland Bay. This channel is maintained to a depth of 11.7 metres to enable ships up to 238 metres to safely enter the Port. To keep the channel open to shipping, the Port of Townsville has been carrying out maintenance dredging since 1883.

The Port of Townsville is required to maintain a safe shipping channel and harbour to provide an efficient port which services the North Queensland community. The Port of Townsville also maintains appropriate depths so that commercial vessels (such as ferries, barges and fishing vessels) and private boats can continue to access Ross Creek, Ross River and the Marine Precinct.

Maintenance dredging is usually undertaken once a year for around 4-5 weeks, depending on the amount of sediment building up in the channel and harbour.

How do we know when maintenance dredging works are needed?

The Port’s Hydrographic Surveyors use specialist equipment and carry out detailed surveying four times per year. They measure the depth of the water around the port and monitor the volume of sediment accumulating in the channel. The survey results are measured against the navigational target depths for the port, anticipated shipping trends, projects or developments that may affect navigational requirements. The port works closely with the Maritime Safety Queensland Regional Harbour Master to determine if and when dredging is required.

PORT OF TOWNSVILLE - Capital Dredging Works 1993 Environmental Monitoring Program