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Land Reclamation at Yellow River

USGS; Link:

The Huang He (or Yellow River) in China is the river with the highest amount of sediment worldwide. Over time, fortified settlements and industrial facilities have been built on sediment that had been deposited in the river delta. In the middle of the nineteenth century, dams and levees were set up in order to protect the new infrastructure against floods. Since the 1970s, the river levels in the delta have been falling continually due to the increased demand for water. These two satellite images give you an idea of the modifications the delta underwent within twenty years.


Great Barrier Reef


Containing 2900 single reefs and 71 coral islands, the Great Barrier Reef off the coast of Australia is the largest reef system in the world. In this satellite image, the Great Barrier Reef contrasts with the dark sea water due to the strong reflections of the reef material, which is rich in carbonate. Right off the coast, you can see how sediment flows into the ocean while, once it enters the open sea, its colour can no longer be distinguished from the sea water due to vortices.


Location: Australia
Picture taken on August 6, 2004
Sensor: Terra MODIS

Floods in Australia

NASA/GSFC (Jesse Allen); Link:

Heavy rainfall in Queensland, Australia, caused the flooding of Fitzroy River in January 2011. Large parts of the city of Rockhampton were flooded as well. This false-colour image highlights the contrast between the brown water of the river, which is rich in sediment, and its surroundings. The light-reflecting surfaces of the buildings and of the clouds framing this scene are pearly-white. When the floods started to retreat at the end of January 2011, it left a mixture of mud, water and destroyed infrastructure behind.


Susitna Glacier in Alaska

NASA/GSFC (Jesse Allen, Robert Simmon)

In this false colour image, the Susitna Glacier in Alaska seems like a river fed by its influent streams and flowing towards the valley. Due to the depiction in false colour, the vegetation in this picture is bright red, the pure surface of the ice is light blue and white, ice covered with sediment (medial and lateral moraines) is brown and water is dark blue. The dynamics of the glacier are most striking in the middle of the picture where you can see a tributary glacier pushing its ice masses sideways into the trunk glacier.


Location: Alaska