An established river stage/elevation at a given location along a river which is intended to represent the maximum safe water level that will not overflow the river banks or cause any significant damage within the river reach.

the maximum height of the river before it overflows its banks. Being above bankfull does not necessarily mean that it causes damage (it depends on the particular river and what development exists along it).

This stage is delineated by the Elevation point of incipient flooding, indicated by deposits of sand or silt at the active scour mark, break in Stream bank slope, perennial vegetation limit, rock discoloration, and root hair exposure