- For channels, the stage-discharge curve is called a rating curve (Fig. 10).
- Such a curve is generated for all stream gauging stations (e.g. USGS stations).
- The form of the curve can be approximated in various ways, usually termed the Convex Method (i.e. to approximate the typical shape of rating curves)
- One approximation, the kinematic wave method assumes
shallow overland flow (also applicable for wide channels)
- assume discharge depends only on flow depth (stage)

- plotting the rating curve on log-log paper gives an approximately straight line
- using this diagram, is the intercept (i.e. the logarithm of the discharge at area = 1.0), and is the slope of the line

- assume discharge depends only on flow depth (stage)
- This is the simplest channel routing method used in WMS
- When a rating curve is unavailable, one can be estimated using Manning's Equation

Dr. T. Brikowski, UTD. All rights reserved.