Dredging through the Great Barrier Reef debate
The Great Barrier Reef has been a hot topic in the media due to a dredging saga that some claim is the beginning of the end for one of our greatest national treasures and tourist attractions. Depending on who you listen to, this claim is bang on the money or a merely unfounded exaggeration.
This divisive issue is the result of nine mega coalmines planned for the Galilee Basin in western Queensland which, if approved, would single-handedly double Australia's coal output. Mining magnates Gina Rinehart and Clive Palmer – surprise surprise! – both have a stake. Where there's smoke there's fire, and where there's money to be mined there's probably Gina and Clive (coming soon to Netflix).
Just as important as mining the coal, however, is the infrastructure required to export it, which includes ports. And guess which coastline is closest to the Galilee Basin? This is where the Great Barrier Reef comes in. It’s unfortunately geographically caught between Australia's next mining venture and the ravenous global resource market.
The major port of interest is at Abbot Point, which is right next to the Great Barrier Reef World Heritage Area. There’s already one terminal at Abbot Point but in December federal Environment Minister Greg Hunt approved the addition of three extra terminals. This will increase the number of ship berths from two to eight to accommodate all the extra coal output from the Galilee Basin.
The most obvious environmental impact of the port’s expansion is the increased shipping traffic that it will lead to through this world heritage area. Yet an even more controversial side-effect is the dredging required to construct the new terminals.
What even is dredging?
It’s hard to deny the negative and emotive connotations of the word ‘dredging’. At first glance, it’s an ugly word that jumps out from headlines and conjures up thoughts of the industrial and the dirty. The word dredging is hardly an activity that many want associated with one of the seven natural wonders of the world. But what exactly does it mean?
Dredging is the removal of sediment from the bottom of bodies of water to maintain or increase the depth of channels or berthing areas for ships. In the Great Barrier Reef, dredging will remove debris from the seabed to create a suitable depth for coal ships to approach the shore and berth at the Abbot Point port, so they can pick up their precious cargo.
Removing the sediment isn't really the issue: the debate really centres on where it should be disposed. As a major shock to many environmentalists in January, the Great Barrier Reef Marine Park Authority (GBRMPA) approved the dumping of this dredge soil in the boundaries of the protected marine park.
This approval is contingent on 47 strict conditions, including confining the disposal to an area free of coral and seagrass beds around 40km from the nearest offshore reef. Disposal will also be restricted to a four-month window outside of any coral spawning and seagrass growth periods, and can be halted at any time if unexpected oceanic conditions cause adverse effects.
GBRMPA Chairman Russell Reichelt recently defended the authority’s decision in The Conversation and tried to act all Mythbusters on comments that it will lead to toxic sludge or slag waste. “The reality is that disposal of dredge material of this type in the Marine Park is not new. It has occurred off nearly all major regional centres along the reef’s coastline before now,” says Reichelt.
“The material itself in Abbot Bay is about 60 per cent sand and 40 per cent silt and clay, which is similar to what you would see if you dug up the site where the material is to be relocated. In addition, testing by accredited laboratories shows the material is not toxic, and is therefore suitable for ocean disposal," he says.
Unsurprisingly, Reichelt and the GBRMPA’s decision is still sparking outrage from environmentalists both domestically and abroad. In late January, 233 scientists lobbied the GBRMPA to reject the proposal by co-writing a letter to Riechelt that clearly stated their objection to threatening the reef with dredge disposal.
“The best available science makes it very clear that expansion of the port at Abbot Point will have detrimental effects on the Great Barrier Reef. Sediment from dredging can smother corals and seagrasses and expose them to poisons and elevated nutrients,” reads the letter.
One of the letter’s signatories, University of Queensland scientist Selina Ward, told 3AW that 3D modelling and recent research of Gladstone Harbour show that dredging soil is a threat to ecosystems outside of its immediate vicinity. “When you place a large amount of sediment in the water like this, it's not going to sit still. It's very likely that it will move considerable distances,” she said. According to Greenpeace spokeswoman Loiuse Matthieson, these “muddy plumes” can spread as far as 80km from the original dumping site.
Remarkably, this was the same concern raised by the GBRMPA last year in documents obtained by an FOI request by Greenpeace. The uncovered executive draft assessment indicates substantial internal concern that dredging disposal would be a major threat to the fragile reef.
“The GBRMPA believes that the proposal in its current form should be refused a Great Barrier Reef Marine Park permit…The proposal to dredge and dispose of up to 1.6 million cubic metres of sediment per year…has the potential to cause long-term, irreversible harm,” reads the draft assessment.
In particular, the GBRMPA highlighted the “sub-standard and possibly under representative modelling” used to predict the area affected by suspended sediments. In their eyes (at least at the time) there was a gross underestimate on the dredging’s effects that failed to take into account the degree to which suspended sediment might disperse. According to Reichelt, these views were only a working draft that did not take into the “strictest conditions that we have ever imposed on such a project”, without which the project would have most likely been declined.
Interestingly, the draft assessment also proposed an alternative to dredging: lengthening the port’s trestles. This would basically make the pier longer so ships can berth further out to sea, where the water level is already naturally deeper and thus the reef requires minimal dredging or none at all.
Jon Brodie, a Senior Principal Research Officer at James Cook University, supports disposing the sediment behind a retaining barrier called a ‘bund wall’. Even Greg Hunt, in his initial announcement of the Abbot Point expansion, highlighted the importance of using the material not for dumping but land infill and land reclamation disposal although, following the GBRMPA’s approval, the government jumped on board.
The disposal of dredging soil in the GBR may damage the ecosystem or it may have no effect at all. The science is, at best, debatable. What is outrageous is that an authority would experiment with risky industrial processes with unforeseeable impacts that may irreparably damage a reef that it’s supposed to protect… especially when there are known alternatives available.
Until the science is clear, a line needs to be drawn on the sands of the coral sea in Queensland. Don't mess with our reef.
Ben Latham goes to Australian National University and is studying a Bachelor of Science/Arts.
Image: Wikipedia Commons