Orbital View: Braids of Water

Editor’s Note: This article previously appeared in a different format as part of The Atlantic’s Notes section, retired in 2021.

Cutting through the countryside of southern New Zealand:

The braided Rakaia River carries glacial runoff from #NewZealand’s Southern Alps to the Pacific Ocean.

A photo posted by Planet Labs (@planetlabs) on

A similar view of the braided Rakaia was voted the most popular satellite image among DigitalGlobe fans. So what’s a braided river exactly?

It has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars or, in British usage, aits or eyots. Braided streams occur in rivers with high slope and/or large sediment load. Braided channels are also typical of environments that dramatically decrease channel depth, and consequently channel velocity, such as river deltas, alluvial fans and peneplains. Braided rivers, as distinct from meandering rivers, occur when a threshold level of sediment load or slope is reached.

(See all Orbital Views here)