Dredging initiatives in Queensland
Maritime Safety Queensland is committed to maintaining navigable access in high-use waterways for recreational boating. With the rapid increase in recreational boating activity on our waterways, the need for dredging is always high. Waterways are often a complex network of naturally shallow areas and channels and many of these areas constantly shift through natural processes. This sometimes results in shallow waterways in places which can pose difficulties for vessel operators. Potential new dredging projects are identified through the Maritime Safety Queensland-managed Boating Infrastructure Capital and Maintenance Program.
What is dredging?
Dredging is an excavation activity that artificially deepens and widens harbours and waterway channels. The process of dredging involves using machinery to gather up bottom sediments such as sand, silt or mud. In some locations in Queensland, such as the Gold Coast and southern Moreton Bay, sediment is generally clean sand that can be used for land fill or nourishing beaches.
Dredging keeps waterway channels navigable for recreational boat users and also has significant flood mitigation benefits in rivers.
Recently completed dredging projects:
- South Channel, Gold Coast Broadwater – maintenance dredging (completed early March 2011)
- North Channel, Gold Coast Broadwater – maintenance dredging (completed February 2011)
- West Crab Island Channel – maintenance dredging (completed December 2010)
- One Mile Entrance Channel – bed levelling works (completed October 2010)
- Mooloolah River entrance – dredging and beach nourishment, joint project with Sunshine Coast Regional Council (completed August 2010)
- Cabbage Tree Creek Boat Harbour – bed levelling works (completed August 2010)
Current projects:
- Cabbage Tree Creek Boat Harbour entrance channel (estimated completion April 2011)
- Gold Coast Seaway entrance – dredging, a joint initiative with Gold Coast City Council (estimated to commence in April 2011)
- Jacobs Well Channel – dredging (estimated completion August 2011)
Gold Coast dredging
Boating activity on the Gold Coast waterways is growing steadily and 11.5% of Queensland's recreational boats are now located in the Gold Coast region. In the past five years there has been a 6% increase in registered recreational vessels on the Gold Coast. Based on the latest figures, there are now more than 26 800 recreational boats and about 900 commercial vessels registered in the Gold Coast area.
In the past five years the Queensland Government has invested A$12 million in maintaining the Gold Coast waterways channel network on dredging projects and the Gold Coast Seaway sand-bypassing system.
Maritime Safety Queensland and the Gold Coast City Council have together made a commitment to provide A$2.5 million annually towards Gold Coast dredging initiatives on an ongoing basis. These funds are administered by the Gold Coast Waterways Steering Committee, a group formed to oversee waterway development including dredging in the Gold Coast and southern Moreton Bay area. The committee, comprising representatives from the state government, Gold Coast City Council and Marine Queensland, have already undertaken several dredging projects as listed above.
History of the Gold Coast Seaway
Before the construction of the Gold Coast Seaway in 1986, the Nerang River entrance to the Pacific Ocean (locally known as the Southport Bar) had a history of instability. Predominant south-easterly winds, the significant northerly littoral drift and wave climate combined to move an estimated 500,000 cubic metres of sand along the south-east Queensland coast each year. Over time the Nerang River mouth also moved northward by up to 60 metres each year, causing land erosion and changing sandbanks at the bar and adjoining Broadwater.
In the early 1800s the Nerang River entered the Pacific Ocean where Jupiters Casino is now located. In 1930 the entrance was where Seaworld stands today. It was estimated that by 2050, the entrance would be opposite Runaway Bay if no action was taken, and the township of Currigee on South Stradbroke Island would be in danger.
The Queensland Government took action to stabilise the river mouth, with construction of the Gold Coast Seaway taking place between 1984 and 1986. The sand bypass system was provided for in the design of the Gold Coast Seaway as it was recognised that the breakwaters would not be effective for long without a solution to the littoral drift problem. The large-capacity fixed-sand bypassing system is an integral part of the design of the seaway.
This series of historical photos shows that, since the installation of the Gold Coast Seaway, navigability in the Broadwater has improved. A larger version of this map (JPG, 114 KB) is available for viewing in a seperate window.
Have your say
Contact Boating Infrastucture and Waterways Management Branch via:
- Email: goldcoastdredging@tmr.qld.gov.au
- Telephone: +61 7 3120 7198z
- Mail: Gold Coast dredging initiatives
Maritime Safety Queensland
GPO Box 2595
Brisbane Queensland 4001
zLocal call – higher rates may apply outside local area or from mobile phones.
