AS 3778.4.2-1991

1 - AS 3778.4.2-1991 MEASUREMENT OF WATER FLOW IN OPEN CHANNELS - MEASUREMENT USING FLOW GAUGING STRUCTURES - RECTANGULAR BROAD-C
4 - PREFACE
6 - 1 Scope and field of application
6 - 2 References
6 - 3 Definitions
6 - 4 Installation
6 - 4.1 Selection of site
7 - 4.2 Installation conditions
7 - 4.2.1 General requirements
7 - 4.2.2 The approach channel
7 - 4.2.3 The measuring structure
7 - 4.2.4 Downstream of the structure
8 - 5 Maintenance - General requirements
8 - 6 Measurement of head(s)
8 - 6.1 General requirements
8 - 6.2 Stilling or float well
8 - 6.3 Zero setting
8 - 7 Rectangular broad-crested weirs
8 - 7.1 Specification for the standard weir
8 - 7.2 Location of the head gauge section
9 - 7.3 Provision for modular flow
9 - 8 Discharge relationships
9 - 8.1 Discharge equation
9 - 8.2 Discharge coefficient
11 - 8.3 Limitations
11 - 8.4 Accuracy
11 - 9 Uncertainties in flow measurement
11 - 9.1 General
12 - 9.2 Sources of error
12 - 9.3 Types of error
12 - 9.4 Uncertainties in coefficient values
12 - 9.5 Uncertainties in measurements made by the user
13 - 9.6 Combination of uncertainties
13 - 9.7 Presentation of results
13 - 10 Example
15 - Annex A - Nomenclature
16 - Annex B - Submerged flow
17 - Annex C - Gauged head discharge coefficient and total head discharge coefficient

Specifies the requirements for the use of rectangular broad-crested weirs for the measurement of water flow in open channels under free flow conditions. It is technically identical with and reproduced from ISO 3846:1989.

This International Standard lays downrequirements for the use of rectangular broad-crested weirs for the measurement of flow of clear water in open channels under free flow conditions.Annexes A, B and C form an integral part of this International Standard.

First published as AS 3778.4.2-1991.