Dredging for recreational access
We maintain channels for recreational boating in high-use waterways for access to facilities owned by the department when it is financially and environmentally feasible to do so. With the continuing growth in recreational boating, the expectation for dredging is always high.
Potential new dredging projects are identified through proposals received from councils and port authorities, information provided by boating organisations and individual boat users, plus an extensive ongoing program of hydrographic surveys to monitor changes in channel depths.
Waterways are often a complex network of naturally shallow areas and deeper channels with many of these constantly changing in response to natural processes. This sometimes results in shoaling that poses difficulties for some boat owners.
Dredging is an excavation activity that artificially deepens or widens waterways to improve navigational safety or to maintain particular design depths. The process of dredging involves using machinery to gather up bottom sediments such as sand, silt or mud. In some locations sediment is clean sand that can be used for land fill or nourishing beaches. In other locations an environmentally responsible method of disposing of dredged material needs to be found for each dredging project. This is particularly the case where sediments are contaminated.
Dredging we undertake
Due to the natural movement of material, it is not always cost effective or environmentally responsible to dredge in all locations that may be desired by boat owners. Capital cost, potential future maintenance dredging costs and environmental considerations are key factors considered when assessing potential dredging projects.
We focus our limited dredging funds, drawn largely from recreational boat registration fees, on providing access to all-tide facilities in state boat harbours plus selected high-use channels elsewhere. Examples of high-use channels outside state boat harbours that we dredge include the approach to the public boat ramp at Gatakers Landing (near Urangan), Molongle Creek (north of Bowen), the One Mile entrance at Dunwich on North Stradbroke Island, and the Endeavour River entrance to Cooktown. These sites are high-use waterways that provide access to facilities owned by us.
Dredging we do not undertake
Dredging intended mainly to benefit commercial vessel operations or within privately leased areas is not usually funded from the Marine Infrastructure Investment Program.
The dredging of coastal creeks and rivers is not normally feasible unless the waterway is within a major trading port, where the funding is provided by the port authority from shipping and commercial vessel levies. In such cases the port authority usually carries out the dredging.
The dredging of channels through bars at the entrances of coastal creeks and rivers to provide access to public boat launching and landing facilities is a low priority for funding allocation. Similarly, channels within coastal creeks and rivers are a low priority.
This is because:
- benefits gained in the short term are usually soon lost through siltation and shifting banks
- the costs of initial capital dredging and ongoing maintenance dredging are prohibitive
- there may be unacceptable environmental impacts on upstream waterway ecology – such as salinity penetrating further inland – meaning that environmental dredging approvals (and supply of suitable environmental offsets) are extremely difficult to arrange.
We do not dredge privately owned or managed channels or resort complexes, for instance One Mile Creek, Cardwell (known as Port Hinchinbrook) or Laguna Quays (north of Mackay).
Councils and other entities may undertake dredging for any purpose including boating projects that do not meet requirements for funding by the state government. This includes approaches to boat ramps and entrances to creeks and rivers. Aside from boating access, council dredging campaigns are often associated with flood mitigation, beach nourishment, and foreshore stability.