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Queensland: Beautiful one day, a brown stain the next

Related Stories Map: Brisbane 4000

Earth image Recent storms across south eastern Queensland filled waterways with sediments flowing down the Brisbane River and staining the usually beautiful blue Moreton Bay a muddy brown.

The deadly storm on May 1 was caused by an east coast low.

The storm dropped more than 360 millimetres of rain in just three hours, sparking flash flooding and causing distinct river plumes to form along the Queensland coastline.

On May 3, after the storm had passed, the Operational Land Imager on the Landsat 8 satellite acquired this view of a brown plume from the Brisbane River entering Moreton Bay.

Flood waters usually contain elevated levels of sediment and coloured dissolved organic matter.

Sediment tends to scatter red light, and coloured dissolved organic matter absorbs blue light.

As a result, a brown colour is visible at the river's mouth where these two optical phenomena work in concert.

However, as you move farther away from the river mouth, the coarser sediments tend to settle to the bottom but the coloured dissolved organic matter still hangs around in the water column absorbing blue light.

Scientists think the elevated levels of coloured dissolved organic matter cause the yellow-green patches in Moreton Bay.

It was the second time in as many weeks, the nation's east coast was hit by severe storms and devastating flooding caused by east coast lows.

In late April a similar tempest brought destructive winds, heavy rains and floods to the New South Wales coast.

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