BS ISO 1070:2018
$167.15
Hydrometry. Slope-area method
| Published By | Publication Date | Number of Pages |
| BSI | 2018 | 36 |
This document specifies a method of determining discharge in open channels from observations of the surface slope and cross-sectional area of the channel.
It is applicable to use under special conditions when direct measurement of discharge by typically more accurate methods, such as the velocity-area method, is not possible. Generally, the method can be used to determine discharge
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for a peak flow that left high-water marks along the stream banks,
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for a peak flow that left marks on a series of water-level gauges or where peak stages were recorded by that series of gauges, and
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for flow observed at the time of determining gauge heights from a series of gauges.
The method is commonly used to undertake the extension of stage–discharge relationships above the highest gauged flows.
It does not apply to determining discharges in tidal reaches.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 7 | Foreword |
| 8 | Introduction |
| 9 | 1 Scope 2 Normative references 3 Terms and definitions 4 Principle of the method of measurement |
| 11 | 5 Selection and demarcation of site 5.1 Initial survey of site 5.2 Selection of site 5.3 Demarcation of site |
| 12 | 6 Measurement of slope 6.1 High-water marks 6.2 Crest-stage gauges 6.3 Pressure transmitters 6.4 Reference gauge 7 Determination of slope |
| 13 | 8 Cross sections of a stream 8.1 Number and location of cross sections 8.2 Measurement of cross-sectional profiles 9 Computation of discharge 9.1 General 9.2 Uniform cross sections 9.2.1 General |
| 14 | 9.2.2 Determination of the mean cross-sectional area and mean wetted perimeter of the reach 9.2.3 Determination of hydraulic radius |
| 15 | 9.2.4 Determination of the mean velocity in the reach |
| 16 | 9.3 Non-uniform cross sections (2-cross-section formulation) 9.3.1 General 9.3.2 Computation of conveyance 9.3.3 Evaluation of the friction slope |
| 19 | 9.4 Composite cross sections |
| 20 | 9.5 Computation of discharge using three or more cross sections |
| 21 | 9.6 State of flow 10 Alternative methods to estimate conveyance 10.1 General 10.2 Divided channel method 10.3 Conveyance estimation system 11 Uncertainty in flow measurement 11.1 Definition of uncertainty |
| 22 | 11.2 Sources of uncertainty for a uniform reach 11.2.1 General considerations 11.2.2 Uncertainty of the mean cross-sectional area |
| 23 | 11.2.3 Uncertainty in the calculation of the mean wetted perimeter 11.2.4 Uncertainties in determination of the friction slope 11.2.5 Uncertainty due to the choice of the rugosity coefficient |
| 24 | 11.2.6 Overall uncertainty in the measurement of discharge |
| 25 | Annex A (informative) Approximate value of coefficients n and C for open channels |
| 28 | Annex B (informative) Approximate value of Strickler-coefficients kSt for natural streams |
| 30 | Annex C (informative) US Soil Conservation Service method of estimating Manning’s n |
| 32 | Annex D (informative) Conveyance estimation system |
| 34 | Bibliography |
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