rating curve

(1) A graphic representation of a Rating Table (see below). (2) A curve showing the relation between Gage Height and discharge of a stream or conduit at a given Gaging Station. (3) A curve showing the relation between the discharge of a gage, meter, or other hydraulic structure or instrument and the pertinent hydraulic conditions affecting the discharge, such as pressure, hydrostatic head, and velocity of approach. If more than one condition affects discharge, a family of curves is needed to represent the rating.