Imprint GTC Data Protection
The river Loisach (dark water) meets the river Isar (bright water) in the Pupplinger Au, a floodplain forest in Southern Germany.

Flood Generates Colour

By Angelika Jung-Hüttl

What's new? | September 2017

It reminds a bit of the Brazilian rain forest - at the famous location where the dark waters of Rio Negro river meets the bright waters of Amazonas. But it is a landscape in Southern Germany, a floodplain forest at the northern rim of the Alps, called Pupplinger Au - very small, totally only 7 kilometres long and 2 kilometres wide. There the rivers Loisach (dark water) and Isar (bright water) meet. After heavy rainfalls in the Alps the water rises in the river beds. They change from very calm to wild and turbid - and they get intensive colours.

Where does the intensive colours come from? Heavy rainfalls wash a lot of soil, sand and loose stone into the rivers and make them murky. Calcarous rock particles and a bed of light-coloured gravel make the Isar water milky and bright. The river Loisach flows through a huge marsh where it absorbes a lot of soil and humic acids before it reaches the floodplain forest. This makes it dark brown and muddy.

The different loads cause different concentrations. So the waters cannot mix at once at the confluence.  For some hundred metres the two river waters flow side by side in one bed creating spectacular swirls.

Heavy and clouded with diffent loads the two rivers create a band of swirls when they come together.

No comments

Write a comment
Your personal data will be processed by us for the publication of your blog post in accordance with our data protection declaration.
This website uses cookies to make your visit more efficient and to offer you more user-friendliness. more informationsclose