Rain is concentrated on Queensland’s eastern seaboard.

Rainwater rushes down the slopes of the East Australian Cordillera and into the Murray-Darling river system.

Australia’s longest river system, the Darling crosses 3,000 km of outback and reaches the ocean on the south coast near Adelaide.

The river basin is relatively flat, with an average gradient of just 16 mm per kilometre.

The floodwaters will take one to two months to reach the ocean.

On 8 January 2011, SPOT 5 acquires a series of images of the Darling River system south of St George, a town near the border between Queensland and New South Wales.

These images show the front end of the floodwaters. The reddish-coloured muddy waters stretch across a 40 km wide area in this irrigated agricultural ecosystem.

The waters stretch back towards the north-east over a distance of almost 300 km.

SIS, an Astrium subsidiary in Australia, re-tasks the SPOT constellation to monitor the floods, in response to requests from Queensland’s civil defence services and Geoscience Australia.

The satellite programming plans are duly optimized to match emergency response operations on the ground.

Forecasts of how the floods will evolve will also be modelled.

This service based on satellite imagery is a valuable aid for civil defence services as they plan operations.