The impact of dredging and dumping sediment on the Great Barrier Reef has been far greater than the mining industry has claimed, with nearly 150m tonnes of new dredging set to take place in the reef’s waters, a study shows.



The report collated by the Australian Marine Conservation Society states that the reef is under “unprecedented” threat from the proposed expansion of coastal ports and industrial development.

Planned expansion of ports, or the creation of new ones, at sites including Gladstone, the Fitzroy Delta, Abbot Point and Townsville, would involve dredging 149m tonnes of seabed to allow large ships to access ports.

The society’s report warns that the dredging process is dangerous to marine life. Worse, should this sediment be dumped within the Great Barrier Reef world heritage area, corals and seagrasses would be damaged, impacting animals such as dugongs and sea turtles.



The amount of damage caused to the reef by coastal development and dredging has proved highly contentious after the government’s decision to approve five million tonnes of sediment being dumped within the reef’s marine park, as part of the expansion of Abbot Point, near Bowen.

The mining industry has pointed to research showing the degradation of the reef is down to cyclones, bleaching and coral-eating starfish, rather than dredging. The Queensland Resource Council has branded groups such as WWF as dishonest, launching a series of TV ads to argue its case.

But in an assessment of the health of the Great Barrier Reef released last week, Unesco said it had “concern” over the dredging program, querying why work on ports had begun before a long-term strategic plan was in place.

The society’s report states that previous dredging, such as at Hay Point in 2006, damaged corals, contrary to industry claims.

“The evaluation of the impacts at Hay Point dredging stated that most of the coral colonies were healthy and that more than 95% of corals were undamaged,” the report said. “However, the way that health and damage of corals was recorded at Hay Point clouds this interpretation.

“Corals that had dead patches, but that were believed to be recovering because of new growth, were grouped together with corals that had no damage at all. Recording damage in this way has obscured the fact that these corals were damaged and underestimated the impacts of the dredging.”

Dr Selina Ward, a coral scientist at the University of Queensland, said the monitoring of projects such as Hay Point was problematic.

“We know some corals had up to 60% coverage by sediment which would have been damaging for them,” she said.

“How did they cope into the future? We don’t know because the monitoring stopped six months after the dredging.

“There are many methods for measuring coral health that weren’t used in the monitoring, and as a scientist I question the results.”

Felicity Wishart, campaign director at the conservation society, said the planned increase in dredging could have a significant impact upon the reef.

“This report highlights that the industrialisation of the reef’s coast through expanded ports will continue to cause environmental damage to the reef if it goes ahead,” she said.

North Queensland Bulk Ports Corporation, which will oversee the expansion of Abbot Point, said it would never propose any plan which would adversely impact the reef.

Brad Fish, chief executive of NQBP, said Unesco had overlooked scientific work which showed it would be unlikely that the development would degrade the reef.

“For Unesco to suggest that other options to develop and dispose of dredged material have not been fully investigated is not supported by the work that has been undertaken over the last 24 months and is an overly simplistic assessment of the range of issues at Abbot Point,” he said.