Most rivers flow in one broad channel of water, but some rivers split into lots of small channels that continually split and join each other to give a braided appearance. These are called braided rivers.

Braided rivers are usually wide but shallow. They typically form on fairly steep slopes and carry large amount of coarse-grained sediments. When the river’s flow decreases, these sediments get deposited on the river bed leaving behind small temporary islands of sands that cause the river’s channel to split. Aside from a steep gradient and abundance of sediments, a variable water discharge rate is essential to their formation. Consequently, braided rivers exist near mountainous regions, especially those with glaciers. Braided channels are also found in environments that dramatically decrease channel depth, and hence channel velocity, such as river deltas, alluvial fans and peneplains.

A braided river in Iceland. Photo credit: Andre Ermolaev/500px