The relationship between stage and discharge is called a rating curve.

A rating curve is the functional relation between stage and discharge.

The development of a rating curve involves two steps.

Rating curves can also be used to evaluate the benefits of various restoration measures on the entire fish community.

After measurements are made for several different levels, a rating table or rating curve may be developed.

In those instances where only a stage measurement is used as the surrogate, a rating curve must be constructed.

An additional rating curve is constructed that relates stage of the stream to cross-sectional area.

This stage-storage relationship is different from stage - discharge relationship (also known as the rating curve).

The relationship between the discharge in the stream at a given cross-section and the level of the stream is described by a rating curve.

Additional algorithms are used to model total building damage costs for each grid cell based on water-depth and speed-depth rating curves.

The rating curve is usually plotted as stage on x-axis versus discharge on y-axis.

Once the rating curve is established, it can be used in conjunction with stage measurements to determine the volumetric streamflow discharge.

Once rated, the discharge in the stream may be determined by measuring the level, and determining the corresponding discharge from the rating curve.

Looped rating curve modification (Jones method)

A rating curve, similar to that used for stage-discharge determinations, is constructed using the mean velocity and the index velocity from the permanently mounted meter.

Rating curves represent the changes in relative area of suitable habitat in response to flow and allow for the determination of habitat quantity at any given flow within the range of surveys.

In combination with hydrologic time series, rating curves are used to create Continuous Under Threshold (CUT) curves for the analysis of frequency, magnitude and duration of significant habitat events.

The technicians and hydrologists responsible for determining the rating curve visit the site routinely, with special trips to measure the hydrologic extremes (floods and droughts), and make a discharge measurement by following an explicit set of instructions.

In hydrology, a Rating curve is a graph of discharge versus stage for a given point on a stream, usually at gauging stations, where the stream discharge is measured across the stream channel with a flow meter.

These rating curves can be developed for river units of any size allowing conclusions to be drawn about the suitability of channel patterns or habitat structures for various species of fish for specific sections as well as for the entire river.