The dam was proposed to stretch from the Traveston Crossing Bridge near Amamoor, 160 kilometres (99 miles) north of Brisbane, south and affect the areas surrounding Bergins Pocket and Kandanga.

The dam would have affected major transport arteries through the area, including the North Coast Railway Line and the Bruce Highway.

It was alleged that reduced fresh water flows to the Great Sandy Strait would have affected the growth of seagrass, the Dugong's primary food source.

Professor Jean Joss of Macquarie University stated, in a submission to the Senate Inquiry 2007: "The Mary River dam would almost certainly push the lungfish to 'Critically Endangered,' and in the long term will lead to its extinction in the wild."

Chairman of the Greater Mary Association, Darryl Stewart, stated: "Estimated annual economic downturn in the downstream communities could be around A$500 million, especially affecting agriculture, fishing and tourism.

[4] The proposed dam aroused opposition from many groups and organisations, from local farmers and fisherman to environmentalists and politicians (both nationally and internationally).

Fraser Island Defenders Organisation, John Sinclair, stated, "The dramatic reduction and almost total blockage of environmental flow into this most significant estuary will heavily impact on these very sensitive aspects of marine ecology.

But not only that, a number of threatened species could be wiped out.”[9] Greens Senator Bob Brown said, "the dam should be opposed because it would flood thousands of hectares of prime food-producing land near Brisbane, Aboriginal heritage sites and the main nursery for the world famous Australian Lungfish.

Fiona Simpson stated, "this strategy and the Water Commissioner’s comments left no doubt that the Traveston Dam was a political decision and desalination was a better and more reliable option.

[13] The independent expert Associate Professor Keith Walker says that the mitigation and offset strategies such as the Freshwater Species Conservation Centre were inadequate, risky and ill-defined and that the proposed fish and turtle ladders were unproven.

The Great Sandy Strait lies between the western fringes of World Heritage Listed Fraser Island and the south-east Queensland coast.