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Monday 26 May 2014

Braided rivers in Iceland

I came across these amazing photos of braided stream patterns near the south coast of Iceland.  Absolutely beautiful -- this is where I found them:

Photographer -- Andre Ermolaev.

These features are among the most ephemeral in the world of glacial geomorphology.  Quite literally, they change by the minute, so there is no real point in trying to map the stream courses.  By the time you get your map finished, the patterns are quite different.....


Steve said...

Beautiful! Thanks for posting & crediting the pics.
As a geomorphologist, how would you define a braided river - as opposed to an anastomising stream?

Steve M

BRIAN JOHN said...

Steve -- my understanding is that braided rivers and streams carry very high sediments loads -- often of boulders and cobbles -- and maintain quite steep gradients. Often there will be virtually no vegetation on a braided river plain because everything keeps on changing -- channels shift position all the time, blocked up with sediments. Then the very turbulent meltwater spils over and finds somewhere else to go.

Anastomosing rivers or streams are multi-channeled, with many intersections and splits, as on estuaries close to sea-level. So gradients are much lower. Sediments may be much finer, and individual channels may be quite long-lived. So there may be a good vegetation cover of grassland, scrub or even forest.

All clear?

Steve said...

Great explanation - thanks.