USGS Storm Words: Rating

The USGS has many missions before, during and after a major storm. Here is an explanation of a word we commonly use with our science.

Is the relationship between river stage and discharge. For many rivers, as stage rises so does the discharge, therefore, ratings are necessary because USGS scientists cannot always be at the 8,200+ nationwide streamgages to measure water discharge. By using ratings, USGS can compute the discharge from variables that are collected without someone on site. It is important to keep ratings up-to-date, so USGS scientists will frequently measure a river or stream’s discharge during or after an intense rain event by physically going to that location and performing a direct measurement.