Cullen Bay Dredging

The Northern Territory Government is undertaking crucial maintenance dredging in the Cullen Bay outer harbour to ensure the continuation of ferry service to Mandorah and the Tiwi Islands.


Once complete, the maintenance dredging works will eliminate the need to cancel ferry services during the low tidal periods.


Maintenance dredging of the harbour occurs every 5 to 7 years and includes the removal of approximately 91,000 cubic metres of sediment build up and relocating it to a new area.

Consultation with the Northern Territory Environment Protection Authority has been undertaken to identify a suitable location to dispose of the dredged sediment. A dredging line has been constructed in a north westerly direction and held in place along the seabed by concrete weights.  Approximately 600 meters from the Cullen Bay Ferry Terminal, the pipeline may become visible where it crosses a sandbank, depending on tide levels. To alert mariners to the location of the pipeline, yellow buoys with quick flashing lights will be positioned every 25 metres.

Access in and out of the marina will be maintained at all times. Boat users will need to exercise caution around the dredging equipment and maintain a safe distance.

Dredging activities will be conducted in accordance with industry best practice and statutory requirements. Regular monitoring of the water quality will be conducted throughout the project to ensure that it remains within the agreed limits of the Dredging License.

The image below illustrates the dredging area:

cullen bay dredging diabram

Possible Changes to Ferry Travel Time

On occasion, the current ferry route will be slightly altered to navigate around dredging machinery, travelling north east of Cullen Bay before docking in the Cullen Bay terminal. This change in route may add up to 4 minutes in travel time in each direction. To minimise disruptions, public bus schedules will be reviewed on a case by case basis to ensure services are still available to disembarking ferry passages. Ferry departure times will not change and will remain as per the existing schedule.

Project Timeline

Dredging operations are underway and will continue through to the first week of June 2018, weather permitting.

Additional information

May 2018Fact sheet  (289.7 kb)Community update
February 2018Stakeholder notice  (1.9 mb)Works commencing

The Stakeholder notice - February 2018 update (1.9 mb) is now available to download.


If you would like further information or would like to raise any concerns, please contact the Department of Infrastructure, Planning and Logistics Manager Projects, Sumesh Dhir via email to or phone 8999 4864.

Last updated: 29 May 2018