Published 14 years ago, updated 6 years ago

Tue, 11 Jan 2011

Queensland’s Great Barrier Reef is being flushed with toxic, pesticide-laden sediment that environmental experts fear could devastate fragile corals and marine life, damage that may require as long as a century to repair.

Hydrologists estimate the equivalent of three Sydney Harbours of floodwater is flowing out to sea through nearby Rockhampton and into the Great Barrier Reef, likely to kill the reef and its inhabitants.

The flood plume stretches 2300km along the coast from Cooktown to Grafton and about 120km out into the Coral Sea. The Great Barrier Reef contributes A$5.4 billion to the Australian economy each year from fishing, recreational use and tourism.

It is the world’s largest reef system, composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres (1,600 mi) over an area of approximately 344,400 square kilometres (133,000 sq mi).

The worst floods Australia has experienced in 50 years, affecting an area the size of France and Germany, have impacted on the state’s tourism, farming, mining and other industries.

The World Wild Life Fund released a statement today stating that the water pollution from flooded farms and towns along the Queensland coast will have a disastrous impact on the Great Barrier Reefs corals and will likely have a significant impact on dugongs, turtles and other marine life.

”In addition to the terrible costs to farmers and communities in Queensland, we will also see a major and extremely harmful decline in water quality on the Great Barrier Reef,” added WWF spokesman Nick Heath.

He said damage to the Great Barrier Reef will be exacerbated because the floods are “bigger, dirtier and more dangerous due to excessive tree clearing, overgrazing and soil compaction”.

Experts expect the reef to recover, but depending on the coral resilience, it could take between 15 and 100 years. The WWF does concede a few species will thrive in the conditions, with Barramundi and prawns relying on the freshwater flood runoff. Large areas of the coast and Reef to the north of flood-affected areas of Queensland are still largely unaffected.

The WWF is blaming farm practices and poor management for some of the runoff. “As devastating and tragic as these floods are, they also provide a chance to introduce newer and better technologies that will reduce pollution and increase profits,” said Heath.

”Better management and design of our farms can reduce the risks to people, livelihoods and wildlife and also lead to greater profits further down the track by increasing deep infiltration and soil moisture, improved topsoil retention and therefore productivity.”

”While the current floods would still have occurred, trees and wetlands slow flood waters down and absorb water, lessening the impact of the flood. We can better prepare for future floods by bringing trees back into previously cleared catchment areas.”

Climate change is likely to deepen the cycle of drought and floods, with further loss of topsoil followed by bigger rainfall events, and therefore increase the damage caused by floods.

Over the past 150 years sediment inflow onto the Great Barrier Reef has increased four to five times, and five to 10 fold for some catchments, while inorganic nitrogen and phosphorous continue to enter the Great Barrier Reef at enhanced levels, according to the Australian Government’s Outlook Report.

by Jeni Bone

From Sail-World.com