Ledge

Position: In-channel

 

Form

Distinctly stepped, flat-topped, elongate, bank-attached unit. Has a straight to gently curved planform, flanking one or both banks. Composed of the same materials as the basal floodplain (i.e. sediments are laterally continuous from the ledge to the floodplain).

 

Process description

Formed by channel expansion processes where flows selectively erode the upper units of the floodplain as the channel incises and expands. Unpaired ledges reflect lateral shift during incision, whereas paired ledges indicate incision only.