BS 3680-3C(1983) : 1983

National foreword
Cooperating organizations
1 Scope and field of application
2 References
3 Definitions and symbols
4 Units of measurement
5 Principles of the stage-discharge relation
6 Calibration of a gauging station
7 Methods of testing stage-discharge curves
8 Uncertainty in the stage-discharge relation and in a
    continuous measurement of discharge
Annexes
A Stage-discharge curve
B Hysteresis in the stage-discharge relation
C Twin gauge station fall-discharge method
D Extrapolation of stage-discharge relation
E Correction for discharge in unsteady flow
Tables
1 Typical manual computation of the stage-discharge
    relation by the method of least squares
2 Tabulation of calculation to determine points for
    plotting stage-discharge curve and constructing
    rating table (manual)
3 Tabulated values required to calculate Se and Smr
4 Typical computation for the uncertainty in the daily
    mean discharge using hourly values of discharge
5 Student's "t" test of check gauging for bias
6 Values of Student's "t" at the 95 % confidence level
Figures
1 Computation of discharge and mean water-level for
    variations of water-level
2 Segment of stage-discharge curve
3 Determination of a - Gauge reading for zero
    discharge
4 Testing of stage-discharge curves
5 Relationship Qn = f(z0) for unit fall Hn = 0,300 m
6 Relationship between Q/Qn and H/Hn
7 Relation of stage to adjusted discharge for
    reference fall (0,300 m)
8 Normal-fall method - Simple rating-curve
9 Relation between normal fall and height
10 Measured discharge-fall relation

Lays down methods of determining the stage-discharge relation for a gauging station. Stable and unstable channels are considered, including those subject to ice conditions, but considerable care must be taken if this is applied to flow conditions which suddenly or rapidly vary. An analysis is included of the uncertainties involved in the preparation and the use of the stage-discharge relation. Covers references, definitions and symbols, units of measurement, calibration of a gauging station, methods of testing stage-discharge curves and uncertainty in the stage-discharge relation and in a continuous measurement of discharge.