BS ISO 1088:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Symbols and abbreviated terms
4 Types of errors and procedure for estimating the
  uncertainties in flow measurement
  4.1 Principle
  4.2 Occurrence of error
  4.3 Sources of error
  4.4 Determination of the individual components of
      the uncertainty
  4.5 Total uncertainty in discharge
5 Collection and processing of data for the investigation
  of component uncertainties - type A evaluation of
  uncertainties
  5.1 Data on the local point velocity
  5.2 Data on the average velocity
  5.3 Data on the velocity-area method
  5.4 Integration method
  5.5 Calibration curves
  5.6 Distance measurements
  5.7 Depth measurements
6 Data processing
  6.1 General
  6.2 Error-type i
  6.3 Error-type ii - Approximation of mean velocity in
      the vertical
  6.4 Error-type iii - Limited number of verticals
Annex A (informative) Characteristics of rivers from which
        data were collected
Annex B (normative) Effect of increasing measuring time
        on uncertainty
Annex C (normative) Local point velocity measurements - Report
        form
Annex D (normative) Average velocity measurements - Report
        form
Annex E (normative) Velocity-area method - Report form
Annex F (informative) Examination of Error Types i, ii, and iii
Annex G (informative) Uncertainties in velocity-area measurement
        components
Annex H (informative) Calculation of the uncertainty in a
        current-meter gauging
Bibliography

Provides a standard basis for the collection and processing of data for the determination of the uncertainties in measurements of discharge in open channels by velocity-area methods using current-meters.

This International Standard provides a standard basis for the collection and processing of data for the determination of the uncertainties in measurements of discharge in open channels by velocity-area methods using current-meters.

To determine the discharge in open channels by the velocity-area method, components of the flow (velocity, depth and breadth) need to be measured. The component measurements are combined to compute the total discharge. The total uncertainty in the computed discharge is a combination of the uncertainties in the measured components.

Clause4 of this International Standard deals with the types of errors and uncertainties involved. Clauses5 and 6 present a standard procedure to estimate the component uncertainties by the collection and processing of the necessary data.

This International Standard is intended to be applied to velocity-area methods that involve measurement of point velocities at a relatively small number of discrete depths and transverse positions in the flow cross-section, as described in ISO748. This International Standard is not intended to be applied to measurements made by Acoustic Doppler Velocity Profilers (ADVP) or other instruments that produce essentially continuous velocity profiles of the flow field.