Key Terms - Bankfull Characteristics

This image shows the Bankfull features etched onto the photograph.

Bankfull discharge (Qbkf ):

Bankfull Discharge: Volumetric flow that fills the Bankfull channel, beyond which the flow spills onto the Floodplain. Bankfull is the discharge at which channel maintenance is the most effective at forming the river. It is important to note that despite the relative effective power of Bankfull flow, channels are formed by the integration of all flows up through Bankfull.

Bankfull depth (dbkf):

Bankfull Depth: Vertical distance from river bottom Datum to point of incipient flooding or Floodplain encroachment. It is often a depth relative to the river Thalweg, and is often noted on point bars. In cut-away banks, opposite point bars, localized scour may place the Bankfull Depth below Floodplain. In some entire Reaches of a river, the Bankfull Depth may be within the channel, and the Floodplain abandoned due to incision.

Bankfull width (Wbkf):

Bankfull Width: Shortest horizontal distance between left and right Bankfull Depth. The width is often taken, and distinguished, at riffles and pools.

Original image courtesy of NCSU