Island

Position: In-channel

 

Form

Vegetated mid-channel bar. Can be emergent at bankfull stage. Generally compound forms, comprising an array of smaller-scale geomorphic units. They are commonly elongate in form, aligned with flow direction scaling to one or more channel widths in length.

 

Process description

Generally form around a bar core that has been stabilised by vegetation. This induces further sedimentation on the island. Islands are differentiated from bar forms by their greater size and persistence, reflecting their relative stability and capacity to store instream sediments. The pattern of smaller-scale geomorphic units reflects the history of flood events and processes which form and rework the island.