Saturday, 9 February 2013

Dredging resumed at the height of Gladstone's record flood

This article was published in today's Queensland Telegraph. Fair minded people might question how dredging at the height of a record flood which left a plume photographed by an astronaut in space days later, could be reconciled with claimed environmental safeguards.

 Above: The fast Dutch dredge Rotterdam sails past Tannum Sands on return from the spoil dumping grounds off Facing Island. Photos taken four days after dredging resumed On January 27, the day the Boyne River peaked at 8.3metres over the Awoonga Dam spillway.
This vessel was washed away from its mooring and foundered near the Boyne mouth. Photo taken the morning that Gladstone Ports Corporation resumed its major dredging project. Apparently turbidity readings showed it was safe to dredge.

Photos and article by John Mikkelsen

GLADSTONE Ports Corporation resumed its controversial  major harbour dredging  at the height of the Australia Day weekend floods, after a brief halt.

This was revealed by a GPC spokesperson in response to questions by The Queensland Telegraph following the re-appearance of the dredges Rotterdam and Al Mahar in harbour waters, which still appeared to be visibly murky from flood waters.

The Rotterdam is a fast, self-propelled trailing suction hopper dredge which dumps spoil at East Banks, off shore near Facing Island. It featured recently in a French TV Planet Hope news feature which focussed on the port developments at Gladstone and Abbot Point. Al Mahaar is a non self-propelled suction cutter dredge.

According to the GPC spokesperson, the dredges resumed operating at 6 am on Sunday, January 27, which was several hours before the Awoonga Dam spillway reached a record overflow height of 8.3 metres and houses downstream at Benaraby and low-lying sections of Boyne/ Tannum were inundated. More than 200 people sought refuge at emergency centres set up at Tanyalla in Tannum Sands and the PCYC in Gladstone. The overflow was about twice the height of the 2010 – 2011 event.

These are facts which we present without comment as historical context. Our questions and replies by the GPC spokesperson on Monday (February 4) are also presented without embellishment below.

“Q. What is the current status of dredging and turbidity? 
A. Dredging stopped when harbour was closed by MSQ at 6pm Thursday 24 January and recommenced when harbour was opened with all dredges operating at 6am on Sunday 27 January.   The initial response to the recent flood event in the Western Basin was extremely high turbidity (300+ NTU). Since the flows have slowed down the harbour is now a mixture of sea water and freshwater. The brackish water leads to the ‘flocculation’ of suspended particles and this causes suspended material that causes turbidity to reduce. This is most pronounced at the surface of the water column and is likely to be the reason for the low turbidity currently being observed in the basin. During our routine monthly monitoring last week we observed very high turbidity in the lower water column, further supporting the process previously described (Jan 2013 WQ report will be related in late Feb on In the medium term this material will settle to the seabed, but if a high energy event occurs (i.e. storm event with strong wind) this material is likely to be resuspended into the water column. This process is not new to the western basin, or any other nearshore marine environment, and has been observed in the past.  Turbidity and Light graphs are updated daily on the Western Basin Port Project website.

Q. Are there any other dredges operating and when did the Rotterdam actually re-commence dredging?  
A. As above.  (There is currently two dredges working on the WBDDP, the Rotterdam and the Al Mahaar.  However, the Castor works periodically on the WBDDP.  All this information is available on the website.

Q. Is it too early to tell how the floods have impacted the shipping channels here (and at Burnett Heads and Port Alma?)
A. At this time surveys are taking place to determine if the floods have impacted shipping channels. Once complete for Gladstone, Port Alma and Bundaberg will be done when safe to do so”.

Meanwhile, an environmental group has questioned how an astronaut saw and photographed the flood plumes on Tuesday, February 29 as published in last Saturday’s Telegraph while harbour monitors apparently showed no problems with turbidity.

Save the Reef said the dramatic pictures of the Queensland flood plume taken by astronauts showed a brown muddy harbour from outer space, “yet Gladstone Ports Corporation’s  water quality monitoring program says it is safe to dredge the inner harbour.

“If Gladstone Ports Corporation’s light monitors say conditions are OK in a flood plume, there must be a problem,” according to spokesperson Dr Libby Connors.

She said Environment Minister Andrew Powell had expressed his concern that the plume would deposit sediment on seagrass meadows, severely damaging them.

‘Despite high turbidity, the light monitoring continues to indicate there is no problem but any lay person can see from the flood plume photos that light cannot reach the harbour floor and the seagrass will struggle to survive, “ she claimed.

“Save the Reef says that these events provide more data for UNESCO to question the capacity of the Queensland and Australian Governments to manage the Great Barrier Reef World Heritage Area.”

(The Federal Government  reported to UNESCO on the management of the Great Barrier Reef World Heritage Area as requested on Friday, February 1. If UNESCO rejects the report, the Great Barrier Reef may be placed on the "In Danger" list).


  1. This time we had a much bigger flood (twice the height over the dam spillway) as in 2011 but so far, much fewer dead fish from the initial flooding. Rockhampton, on the other hand, has had a smaller flood by thousands of dead fish line the river banks. Much controversy over the release of excess water from mine pits during the flooding there.
    Time will tell what the longer term effects are.

  2. The seagrass beds in the inner harbour had not recovered well prior to the Australia Day weekend flood so compounding flood damage with further dredging does not seem to be a good environmental move.

  3. Coincidentally, the employment contract of the GPC,s CEO Mr Leo Zussino will not be renewed when it runs out in August.Mr Zussino had offered to remain longer but the board and Premier Campbell Newman said it was time for a change.

  4. In todays Gladstone Observer the Beaches remain closed
    "Council conducted a third round of testing early this week by sampling recreational waters at Gladstone, Boyne Island, Tannum Sands, Seventeen Seventy and Agnes Water with results assessed under the national guidelines for managing risks for recreational water use.

    Testing showed a variation in results for microbiological parameters with decreases at some beaches and increases at others"

    What other beaches remain closed up and down the coastline following the flood?

  5. I haven't heard of any, Dale. Obviously they are being more cautious here this time which is good, but also in today's Observer there is an article quoting the soon to be departed CEO saying thhere is nothing wrong with the water now or in 2011 when the harbour was closed to fishing for three weeks. He is dirty on the (former Labor government) for approving the closure.
    Will post an article and pics on the QGC pipeline from todays Queensland Telegraph.


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