(Image: Torsten Blackwood/AFP/Getty)

Flood waters in Brisbane reached a 4.46-metre peak at 5.30 am local time today – lower than the 5.2-metre peak predicted earlier this week. By noon, the Bureau of Meteorology reportedthat the Brisbane river was at 3.91 metres and steady.

But with an offshore cyclone now forecast, Reuters reports that further floods are feared – and Brisbane already faces a clean-up operation that may last for months, according to the Sydney Morning Herald.

As things stand, 15 people are now confirmed dead, and a further 61 people remain missing,reports Australia’s Broadcasting Corporation. The environmental implications of the floods are also likely to be profound.

A week ago, fears of a plague of crocodiles and snakes – including venomous taipans, brown snakes and red-bellied blacks – in the Queensland area made the news.

NASA’s Aqua satellite captured this image of the Queensland coast on 4 January. It shows a thick plume of sediment emerging from the Burdekin river mouth and heading for the Great Barrier Reef (Image: Norman Kuring/Ocean Color Web/NASA)

This week there are reports that the Great Barrier Reef is threatened as plumes of dirty flood water from the Burdekin, Fitzroy and Burnett rivers expand into the ocean (see photo above). Underwater visibility has dropped from 50 metres to 1 metre in affected areas, according to theNew Zealand Herald. The inundation of silt threatens to clog the delicate corals, while the drop in salinity may also be problematic for the stenohaline organisms.

But the greatest source of coral mortality may come from an explosion in the coral-eatingcrown-of-thorns starfish population, Katharina Fabricius at the Australian Institute of Marine Science told the New Zealand Herald.

Ominously, three previously observed outbreaks of crown-of-thorns starfish have coincided with large floods in the Burdekin river, Fabricius said.