Stream Discharge Measurement Quality The reference table containing the codes, names, and descriptions of the valid stream discharge measurement quality qualifiers. United States Geological Survey, Surface Water User Group UNSP 1 true unspecified The accuracy of the discharge measurement was not rated. EXCL 2 true excellent (2%) The discharge measurement was rated excellent and it should be within 2% of the actual flow. GOOD 3 true good (5%) The discharge measurement was rated as good and should be within 5% of the actual flow. FAIR 4 true fair (8%) The discharge measurement was rated fair and should be within 8% of the actual flow. POOR 5 true poor (more than 8%) The discharge measurement was rated as poor and should be more than 8% of the actual flow.