AMID all the controversy, do residents actually know how many dredges are operating on Gladstone Harbour?
We hear about dredging in Gladstone almost every day, especially during the past 18 months while the Western Basin Dredging and Disposal Project has been underway.
However, most of us have no idea how many dredges are operating on the harbour and it is worth asking why.
If you are relying on the Dredge Index on page 2 of The Observer every day, here is a little newsflash: that index was designed to tell you how many dredges are operating for the WBDDP, which is by far the biggest project in the harbour.
It has boosted transparency around WBDDP, but it does not tell you there are another three dredging projects underway on the harbour.
The WBDDP, conducted by Gladstone Ports Corporation, has come under intense scrutiny from the media, but most people are probably unaware there are four other dredges operating on the harbour.
The next biggest dredging project is for the Wiggins Island Coal Export Terminal.
The terminal project is dredging about 2.4 million cubic metres of material from the harbour floor - less than one tenth the size of the WBDDP, but still a significant amount.
Here are some details about all the projects:
- The Western Basin Dredging and Disposal Project will remove about 26 million cubic metres of material from Gladstone Harbour over about two and a half years.
- Gladstone Ports Corporation is carrying out the project to allow LNG ships to berth at Curtis Island.
- Currently there are two dredges on this project, although that number varies.
- About 20 million cubic metres of material will be dumped in a reclamation area at Fisherman's Landing. The remainder will be dumped at a location just outside the harbour
- GPC says its project is about 38% complete
- There is one cutter suction dredge undertaking stage one works associated with the berth pocket and swing basin that will provide access for vessels to the completed terminal (about 2.4 million cubic metres).
- A second, small cutter suction dredge is undertaking a minor amount of dredging for the barge wharf (about 10,000 cubic metres).
- A cutter suction dredge "vacuums" material from the seabed, thereby minimising turbidity when compared to other dredging methods.
- The dredged material from WICET is relocated onshore into a reclamation bund and will be utilised for landfill.
- The first phase of stage one dredging began in May this year, continuing for six weeks. The second phase of stage one began in September and is expected to be completed in early 2013.
- About 40% of dredging is complete.
- Dredge management approvals for WICET are aligned with those of the Western Basin Dredging Project.
QCLNG/APLNG - The Narrows
- Dredging began in late August for the 2.3km Narrows crossing of the QCLNG and APLNG gas pipelines.
- The dredging involves a small backhoe dredge mounted on a barge, two tug boats, a survey vessel and a support crew vessel, and is expected to be completed in the next few months.
- After the pipelines are laid in the same trench, they will be covered with rock for protection from shipping.
- The dredging is covered by 21 environmental management plans, 20 permits and more than 600 environmental conditions under state and federal legislation, and is being done by Danish company Rohde Nielsen.
- QGC expects only a minor impact on water quality, turbidity and salinity, and light readings on seagrass are being taken across 16 sites every 15 minutes so work can be stopped if limits are exceeded.
- QGC's seagrass monitoring covers the availability of sunlight, a more environmentally valid indicator to determine impact because seagrass relies on light for growth.
GPC tug base
- A small cutter section dredge is being used at RG Tanna Coal Terminal to prepare a tug base.
- The project will dredge about 250,000 cubic metres of material. About 150,000 has been dredged so far.