BRAIDING

A multichannel or multithread form of channel pattern, where the flow divides around active, low-relief channel bars. Braiding is associated with high and variable discharges, high bedload transport rates, active bank erosion and steep channel slopes. It is found in high-energy river systems, especially in proglacial and semi-arid environments. Occasional extreme floods are needed to maintain this inherently unstable channel pattern, as braiding tends to be reduced by smaller but still competent events in intervening periods. Increased braiding is seen as a likely consequence in some rivers of increases in extreme rainstorms and flood magnitude-frequency changes that are widely predicted to accompany global warming. Changes have also been recorded with climatic changes during the Late Quaternary in tropical Australia.

[See alsoequilibrium concepts in geomorphological and landscape contexts]