BS ISO 9825-2005 Hydrometry - Field measurement of discharge in large rivers and rivers in flood《水文测量 大河和洪水流量的野外测量》.pdf

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1、BRITISH STANDARD BS ISO 9825:2005 Incorporating amendment no. 1 Hydrometry Field measurement of discharge in large rivers and rivers in flood ICS 17.120.20 BS ISO 9825:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 3 October 2005 BSI 20

2、07 ISBN 978 0 580 60493 5 National foreword This British Standard is the UK implementation of ISO 9825:2005. It supersedes BS 3680-3M:1990, which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee CPI/113, Hydrometry, to Subcommittee CPI/113/1, Velocity area m

3、ethods. A list of organizations represented on this subcommittee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer i

4、mmunity from legal obligations. Amendments issued since publication Amd. No. Date Comments 17445 31 October 2007 Addition of supersession details Reference number ISO 9825:2005(E)INTERNATIONAL STANDARD ISO 9825 Second edition 2005-05-15 Hydrometry Field measurement of discharge in large rivers and r

5、ivers in flood Hydromtrie Mesurage in situ du dbit des grandes rivires et des dbits de crue BS ISO 9825:2005ii BS ISO 9825:2005iiiContents Page Foreword iv 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 2 4 Units of measurement 2 5 Appropriate techniques 2 6 Nature of difficulties lik

6、ely to be encountered . 2 6.1 Measured parameters . 2 6.2 Logistical problems 3 7 Measurement of discharge in large rivers 3 7.1 Problems of scale . 3 7.2 Current-meter method 3 7.3 Moving-boat technique. 4 7.4 Acoustic Doppler method 4 7.5 Other methods. 4 8 Measurement of flood flows up to bankful

7、l stage . 5 8.1 Problems of flood-flow measurement. 5 8.2 Use of floats. 5 8.3 Moving-boat technique. 6 8.4 Acoustic Doppler method 6 8.5 Radar 6 8.6 Weirs. 6 8.7 Tracer dilution methods . 6 8.8 Indirect methods . 7 9 Measurement of flood flows above bankfull stage 7 Bibliography . 9 BS ISO 9825:200

8、5 iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for whic

9、h a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all ma

10、tters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circ

11、ulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held respons

12、ible for identifying any or all such patent rights. ISO 9825 was prepared by Technical Committee ISO/TC 113, Hydrometry. This second edition cancels and replaces the first edition (ISO 9825:1994), which has been technically revised. 1Hydrometry Field measurement of discharge in large rivers and rive

13、rs in flood 1 Scope This International Standard deals specifically with the measurement of discharge in large rivers and the measurement of rivers in flood. It also describes the relevant field measurements when it becomes necessary to use indirect methods of estimating discharge. 2 Normative refere

14、nces The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 748, Measurement of liquid flow in open

15、channels Velocity-area methods ISO 772, Hydrometric determinations Vocabulary and symbols ISO 772, Amendment 1:2002 ISO 1070, Liquid flow measurement in open channels Slope-area method ISO 1438-1, Water flow measurement in open channels using weirs and Venturi flumes Part 1: Thin-plate weirs ISO 384

16、6, Liquid flow measurement in open channels by weirs and flumes Rectangular broad-crested weirs ISO 3847, Liquid flow measurement in open channels by weirs and flumes End-depth method for estimation of flow in rectangular channels with a free overfall ISO 4359, Liquid flow measurement in open channe

17、ls Rectangular, trapezoidal and U-shaped flumes ISO 4360, Liquid flow measurement in open channels by weirs and flumes Triangular profile weirs ISO 4369, Measurement of liquid flow in open channels Moving-boat method ISO 4371, Measurement of liquid flow in open channels by weirs and flumes End depth

18、 method for estimation of flow in non-rectangular channels with a free overfall (approximate method) ISO 4374, Liquid flow measurement in open channels Round-nose horizontal broad-crested weirs ISO 4377, Hydrometric determinations Flow measurement in open channels using structures Flat-V weirs ISO 6

19、416, Hydrometry Measurement of discharge by the ultrasonic (acoustic) method ISO 6420, Liquid flow measurement in open channels Position fixing equipment for hydrometric boats BS ISO 9825:20052 ISO 8333, Liquid flow measurement in open channels by weirs and flumes V-shaped broad-crested weirs ISO 92

20、13, Measurement of total discharge in open channels Electromagnetic method using a full-channel- width coil ISO 9555-1, Measurement of liquid flow in open channels Tracer dilution methods for the measurement of steady flow Part 1: General ISO 9555-2, Measurement of liquid flow in open channels Trace

21、r dilution methods for the measurement of steady flow Part 2: Radioactive tracers ISO 9555-3, Measurement of liquid flow in open channels Tracer dilution methods for the measurement of steady flow Part 3: Chemical tracers ISO 9555-4, Measurement of liquid flow in open channels Tracer dilution method

22、s for the measurement of steady flow Part 4: Fluorescent tracer 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 772 and Amendment 1 apply. 4 Units of measurement The units of measurement used in this International Standard are SI units. 5 Appropriate

23、 techniques Due to the dimensions of large rivers and the hazards associated with measuring flood flows, some of the techniques available for discharge measurement on smaller rivers under normal flow conditions may not be appropriate, or may need modification if used. River dimensions, stream condit

24、ions, feasibility of measurements, measuring instruments and equipment, purpose and available funds will, in a general sense, dictate the choice of methodology. In many instances, the choice of technique will be decided upon by the physical conditions at the site. Hazards discussed in this Internati

25、onal Standard are confined to those peculiar to the measurement of discharge of large rivers and rivers in flood. Those techniques that may be partially or entirely appropriate within certain limitations imposed by degree of difficulty of operation are the following: a) velocity-area methods in acco

26、rdance with ISO 748, ISO 4369, ISO 6416, ISO 6420, ISO 9213. b) Tracer dilution methods in accordance with ISO 9555, Parts 1 to 4. c) Weirs and flumes in accordance with ISO 1438-1, ISO 3846, ISO 3847, ISO 4359, ISO 4360, ISO 4371, ISO 4374, ISO 4377, ISO 8333. d) Indirect methods in accordance with

27、 ISO 1070. 6 Nature of difficulties likely to be encountered 6.1 Measured parameters When any of the three parameters used to determine discharge (width, depth and velocity) is abnormally large, it may cause problems that are not usually encountered. BS ISO 9825:2005 3Great width may pose problems f

28、or position fixing in the horizontal, and for measurement of velocity on any overbank spill portion. Great depth may create difficulty in locating a measuring device at the desired depth. High velocities cause problems with regard to maintaining station, position fixing and location of measurements

29、in both the horizontal and vertical. The current meter is required to be calibrated to cover a high range of velocities, for which facilities are generally not readily available. These difficulties are accentuated by problems caused by floating debris, high turbulence and vortices, and movement of l

30、arge bed forms. 6.2 Logistical problems The basic problems in the measurement of discharge of large rivers and rivers in flood are logistic, associated either with the time required for measurement or with the need for special resources to be employed. However, flood measurements may be accompanied

31、by significant additional hazards to personnel and equipment. An additional logistical problem is access to the flood measurement site, both in being able to reach the site and getting to the site in time to measure a high flow. Because of this, indirect measurements assume great importance in the c

32、ase of rivers in flood. 7 Measurement of discharge in large rivers 7.1 Problems of scale The problems relating to measurement of discharge in large rivers are essentially those of the following scales. 7.1.1 Great width For most methods, great width presents difficulties in ascertaining the location

33、 of the measurement with respect to the cross-section, since the orthodox means using tag-lines and optical survey instruments, depending upon the actual dimensions, may preclude accurate results. More sophisticated position-fixing equipment may be needed to overcome this problem, in accordance with

34、 ISO 6420. 7.1.2 Great depth Great depth may call for a greater number of points on the vertical to be measured to sample mean velocity, particularly if the vertical velocity distribution is not uniform due to the section being non-uniform. 7.1.3 High velocity In many cases, high velocity creates di

35、fficulties, both with regard to locating a measuring platform at the desired position on the horizontal and in maintaining that position, as well as enabling the desired point on the vertical to be sampled. The turbulence, which usually accompanies high velocity, both compounds the problems of sampl

36、ing and reduces the accuracy of the measurement. In addition, high velocities require the use of heavy sounding weights, which are difficult to use and increase the risk of injury to field personnel. When using current meters, wet-line distortions lead to time-consuming corrections, and even then th

37、e measurement point may well deviate from the cross-sectional line with which it is meant to conform. 7.2 Current-meter method The standard method for measuring the discharge of large rivers is the velocity-area method using a current meter, from a bridge, cableway, or powerboat or motor launch fitt

38、ed with an echo-sounder. During high velocity, fixing of position and other parameters may be made by cableway with a trolley for rivers up to 500 m wide. From river widths of 500 m up to 1 km, a boat may be moved across the river with the help of a BS ISO 9825:20054 cableway. For river widths great

39、er than 1 km, the use of cableways is excluded. Stationary boats anchored with great care and using conventional survey methods can be located for rivers up to 2 km wide, but for greater widths more sophisticated position-fixing equipment may become necessary. The care required in such operations, c

40、oupled with the need for an adequate number of verticals to be measured, inevitably results in a single measurement becoming a very lengthy procedure. This can be partially reduced by the use of several teams with several boats and current meters. Similarly, advance notice of likely river-stage beha

41、viour enables measurements to be planned to take advantage of stable stage conditions, to counter the problem of lengthy measuring periods. Significant river traffic may cause further delay. 7.3 Moving-boat technique The moving-boat technique is a modification of the current-meter method that reduce

42、s the time required to make a measurement of manageable proportions. Nevertheless, the problem of tracking the boat becomes greater with increasing river width. The fixed depth of the current meter presents problems of uncertainty in determining the mean velocity if the river section varies in depth

43、. It may become necessary to define a number of uniform sections, each of which shall be calibrated by a stationary boat at varying stages. 7.4 Acoustic Doppler method An alternative method is the use of acoustic Doppler meters or profilers for making velocity-area measurements for computation of di

44、scharge. The Doppler profiler is deployed from a powerboat and includes software that computes the river discharge as the boat traverses the river. The Doppler profilers have 3 or 4 transmitter/receiver nodes that transmit acoustic beams through the water column, usually at a 20 angle from vertical.

45、 One beam is used to measure depth and the other beams measure the components of velocity. The Doppler profilers also have an internal compass and bottom-tracking software for measuring distance. The processing software produces a discharge measurement that is similar to velocity-area measurements t

46、hat are made with current meters or the moving-boat technique. The output includes a cross-section profile, area, continuous velocity profiles, and discharge. The Doppler profilers are ideal for measuring wide and deep rivers, because measurements can be made quickly with a 2-person crew of a boat o

47、perator and a technician experienced with Doppler profilers. A typical discharge measurement made using a current profiler will consist of two or more traverses of the powerboat. The discharges derived from each traverse are averaged to obtain the discharge of the measurement. 7.5 Other methods The

48、remaining techniques tend to be less appropriate, largely because of various difficulties when the river is very large. 7.5.1 Floats Floats generally are not used for measuring large rivers because of the difficulty in releasing the floats at the correct location and observing their movement. Howeve

49、r, by stationing observation boats across the observation sections at some convenient interval, it might be possible to overcome the difficulty of large width of rivers. The increase in logistical and procedural problems might be considered tolerable if equipment for the acoustic Doppler, stationary-boat , or moving- boat techniques are not available. 7.5.2 Tracer-dilution techniques Generally, tracer-dilution techniques are not appropriate