Reef Madness
Courtesy of Taso Viglas/Flickr
Late last year, the Australian
government approved a plan to expand a coal terminal at Abbot Point in
Queensland, one of five major ports along the Great Barrier Reef
coastline.
The project involves dredging approximately 5 million tons of
sediment from the seabed to deepen the port. The resulting material will
be dumped 25 kilometers out to sea, inside the boundaries of the Great
Barrier Reef Marine Park. The park authority claims that the approval is
subject to 47 strict environmental conditions that will protect the
reef from damage.
Environmentalists, not surprisingly, are up in arms. Some claim that
the dredge material is toxic and that it will be dumped directly on to
the reef. Neither claim is true—the material is just sand, silt, and
clay, and will be dumped on to bare seabed. But that doesn’t mean that
the project won’t damage the reef. Far from it.
The Great Barrier Reef is a World Heritage Site but has been in
severe decline for decades. For many species and ecosystems—corals,
seagrass, dugongs, turtles, and fish including sharks—the situation is
dire.
The causes of decline are well known: pollution from coastal
development and agricultural run-off, coral diseases, ocean
acidification, coral bleaching, and increasingly severe storms.
Water pollution is a particularly serious threat. Suspended sediment
makes the water murkier, which can deprive sunlight-dependent organisms
such as coral and seagrass of food. Farm run-off also increases the
population of crown-of-thorns starfish, which prey on coral.
At present, the only measure in place to reduce pollution is an
agricultural run-off scheme, which is quite successful but also quite
limited. There is nothing to specifically manage sediment from port
development.
Nonetheless, the Australian government claims that the Abbot Point
project will not affect water quality. In fact, when environment
minister Greg Hunt announced the plan,
he said it would improve water quality. The government expects to
achieve this with an “offset” program that will stop farm run-off from
entering the Coral Sea.
If that sounds too good to be true, that’s because it is. Such improvements to water quality are likely to be impossible.
To offset Abbot Point’s 5 million tons of dredge spoil will require
an equivalent reduction in agricultural sediment over the approximately
five years that the project will run. Given that the total sediment
reaching the Great Barrier Reef from human activities on land is only 6
million tons a year, that is a tall order.
In addition, the rules require that the offset must come from the
watersheds of just two rivers, the Burdekin and Don, which together
contribute less than 3 million tons of sediment a year. Reducing their
discharge by 5 million tons over five years implies restoring them to
almost pristine conditions, requiring the removal of most
agriculture—obviously an impossible and undesirable situation.
Photo by NASA
A further complication is that the offset sediment must consist only
of particles smaller than 15 micrometers across. Given our limited
knowledge of particle size distribution in agricultural run-off, this
creates immense technical hurdles.
Finally, based on the cost of the existing farm run-off scheme, the
overall cost may be as much as $1 billion Australian. The minister’s
statement only mentioned funding of $89 million Australian.
If that weren’t bad enough, three other large Queensland
ports—Cairns, Townsville, and Hay Point—are also planning major
expansions over the next decade. Another, Gladstone, has been undergoing
expansion since 2010.
From the public documents available, I estimate
that these projects will generate a total of up to 150 million tons of
dredge spoil at a rate of 15 million tons a year. To offset the impacts
of all these port developments is even less achievable.
Even more port expansion is likely in the future. The recent approval
of a large coal mine near Alpha, Queensland, will require further
dredging at Abbot Point that is not accounted for in the current
project.
If dredging is not managed well, I expect severe degradation of the
reef as a result. Seagrass beds, the dugongs and turtles that rely on
them, and inshore coral reefs will be severely damaged.
There are a few encouraging signs of improvement, however. Hunt has
ordered that in the future, Gladstone’s spoil will have to be dumped
behind bund walls rather than offshore. Spoil from the expansion of the
port of Cairns may be dumped on land.
Nonetheless, it is clear that under the current regime, management of
port development is not compatible with the Great Barrier Reef’s World
Heritage values.
On top of that, neither the Australian nor Queensland governments
have effective climate policies that would help protect the reef; the
Queensland government rejects the scientific evidence of climate change,
and the position of the Australian government is ambivalent.
So of the three big threats to the Great Barrier Reef—climate change,
coastal development, and agricultural pollution—only the final problem
is being managed on the basis of good science, and then only to some
extent.
There is another way. At Abbot Point, dredging could be avoided
altogether by building a long jetty into deeper water. If dredging must
happen, the spoil could be dumped behind container walls. It is
inexcusable that these options have been rejected: The decision has
clearly been made to expedite the project at the least cost to the
developer but maximum cost to the environment.
This article originally appeared in New Scientist.
Jon Brodie is the chief research scientist at the Centre for Tropical Water & Aquatic Ecosystem Research at James Cook University in Townsville, Australia.
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