Hydrology Corner Blog: Stage-Discharge

International Rating Curve Standards

Rating Curves Workshop – International Best Practices Explored in New Zealand

Stage-discharge rating curves define a unique relation between water level and discharge, enabling continuous derivation of streamflow from water level record. This is important because water level (which is relatively easy to monitor) is only locally relevant whereas discharge (which is relatively difficult to measure directly) is the integral of all runoff processes upstream of the gauge. The vast majority of all streamflow data that has ever been produced is a derived result of a rating curve. In other words, almost everything that we know (or rather that we think we know) about hydrology is a result of rating curves.