1、 ISO 2016 Hydrometry Low cost baffle solution to aid fish passage at triangular profile weirs that conform to ISO 4360 Hydromtrie Projet de chicane faible cot pour faciliter le passage des poissons au niveau des dversoirs profil triangulaire conformes lISO 4360 TECHNICAL REPORT ISO/TR 19234 Referenc
2、e number ISO/TR 19234:2016(E) First edition 2016-12-15 ISO/TR 19234:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
3、or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet
4、 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO/TR 19234:2016(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Symbols 2 5 Principles . 3 6 Installation . 4 6.1 Site selection an
5、d application 4 6.1.1 Restriction . 4 6.1.2 Background. 4 6.1.3 Preliminary survey . 4 6.1.4 Limitations 6 6.2 General arrangement . 6 6.3 Suitability for fish species 8 6.4 Location of the first baffle . 9 6.5 Baffle dimensions 10 6.6 Baffle material and construction 10 7 Maintenance considerations
6、 .11 Bibliography .13 ISO 2016 All rights reserved iii Contents Page ISO/TR 19234:2016(E) 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 ou
7、t through ISO technical committees. Each member body interested in a subject for which 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 co
8、llaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different app
9、roval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the
10、 subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any
11、 trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherence to the World Trade Organi
12、zation (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html The committee responsible for this document is Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 2, Flow measurement structures. iv ISO 2016 All rights reserved ISO/TR 1923
13、4:2016(E) Introduction Flow gauging structures are commonly used for the measurement of open channel flows. To operate satisfactorily, these structures require a head difference to be generated between the upstream and downstream water levels. At structures designed to operate in the modular flow ra
14、nge, an upstream head measurement is used to interpret flow rates. At structures designed to operate in both the modular and drowned flow ranges, the upstream head measurement is augmented by a second measurement which senses tailwater conditions. The former type tends to require higher head losses
15、over the structure. In recent years, greater emphasis has been placed on environmental issues, including the free migration of fish in watercourses. It is acknowledged that flow measurement structures, with their requirement for a head loss between upstream and downstream conditions, may inhibit the
16、 movement of fish. It has become important, therefore, to consider ways of aiding fish migration without seriously affecting flow measurement accuracy. ISO 2016 All rights reserved v Hydrometry Low cost baffle solution to aid fish passage at triangular profile weirs that conform to ISO 4360 1 Scope
17、This document specifies the requirements for the integration of baffles on the downstream face of triangular profile flow measurement structures to aid the passage of fish. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content cons
18、titutes requirements 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 772, Hydrometry Vocabulary and symbols 3 Terms and definitions For the purposes of this document,
19、 the terms and definitions given in ISO 772 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: ISO Online browsing platform: available at http:/ /www.iso.org/obp IEC Electropedia: available at http:/ /www.electropedia.org/ 3.
20、1 diadromous fish fish that migrate between fresh water and sea water to complete their life cycle 3.2 potamodromous fish fish that migrate wholly within fresh water to complete their life cycle 3.3 baffle wall or block attached to the downstream face of the structure to aid fish passage 3.4 aerobic
21、 swimmingsustainable swimming using red muscles, which incur no oxygen debt 3.5 anaerobic swimmingtime limited swimming using white muscles, which incur oxygen debt 3.6 riverine species fish species typically found in and adapted to a flowing water environment TECHNICAL REPORT ISO/TR 19234:2016(E) I
22、SO 2016 All rights reserved 1 ISO/TR 19234:2016(E) 3.7 structural head difference SHD difference in elevation between the crest of the triangular profile weir and the downstream water level at a flow equivalent to Q 95exceedance Note 1 to entry: Q 95 is the flow that is exceeded for 95 % of the time
23、. Note 2 to entry: See Figure 2. 3.8 streaming flow flow which occurs when H 2 /H 1 0,60, whereH 2 is the head on the downstream side of the baffle;H 1 is the head on the upstream side of the baffle 3.9 plunging flow flow which occurs when H 2 /H 1is less than 0,50, whereH 2 is the head on the downs
24、tream side of the baffle;H 1 is the head on the upstream side of the baffle Note 1 to entry: Values between 0,50 and 0,60 can be in hysteresis. 4 Symbols Symbol Term Unit b Breadth of the weir crest perpendicular to the flow direction m h Gauged head relative to the crest (upstream head is inferred
25、if no sub- script is used) m H Total head relative to the crest level m H 1 Head on the upstream side of the baffle m H 2 Head on the downstream side of the baffle m L Distance from the crest to the front of the first baffle m L 1 Distance from the crest to the centre of the first baffle m L 2 Round
26、ed up value of L 1 m L a Maximum apron length m Q 95 Flow that is exceeded for 95 % of the time m 3 s 1 T Height of the first baffle m Ts Height of subsequent baffles m c Slot offset distance immediately downstream from the reflection m d Distance between baffles, centre to centre m p Height of the
27、weir crest above the upstream bed level m q Slot width m aA spreadsheet tool associated with this document is used to design the layout of the baffles in accordance with this document. A link to the spreadsheet is given. http:/ /standards.iso.org/iso/tr/19234 When opening the spreadsheet, be sure to
28、 click on the “Enable Macros “dialogue box.2 ISO 2016 All rights reserved ISO/TR 19234:2016(E) Symbol Term Unit f Offset distance between the position of slots in successive baffles m SHD Crest level above Q 95downstream water level m zL Intermediate variable used in the spreadsheet ato determine lo
29、cal coordinates (left hand side) for determining the slot location zR Intermediate variable used in the spreadsheet ato determine local coor- dinates (right hand side) for determining the slot location dL Intermediate variable used in the spreadsheet afor calculating cutting lengths for the baffles
30、left hand side baffle dR Intermediate variable used in spreadsheet afor calculating cutting lengths for the baffles right hand side baffle aA spreadsheet tool associated with this document is used to design the layout of the baffles in accordance with this document. A link to the spreadsheet is give
31、n. http:/ /standards.iso.org/iso/tr/19234 When opening the spreadsheet, be sure to click on the “Enable Macros “dialogue box. 5 Principles Baffles are placed in parallel rows on the downstream sloping face of a triangular profile weir. There is a slot in each row of baffles that runs at an angle pro
32、gressively across and down the weir face. This oblique channel can be reflected from side to side in narrower channels forming a V-shaped pattern in plan view, see Figures 1 and 3. The baffles retard flow, maintain a consistent depth of water, and prevent water velocities increasing down the weir. T
33、he oblique channel formed by the slots provides a passage route with greater flow depth and lower velocities than over the baffles. The baffles also break the often significant hydraulic jump that typically occurs down the face of weir and moves it further up the weir face where its intensity is gre
34、atly reduced. The solution creates conditions that fish are able to exploit to find passage over a wide range of flows. Fish may exploit the low velocity channel or, when flow tops the baffles, they may swim straight up the slope, taking advantage of the retarded velocity flows created by the baffle
35、s. The difference in elevation between the invert of the weir crest and the top of the first baffle downstream is of critical importance. The dimensions and location should be determined in such a manner that it does not affect the coefficient of discharge of the triangular profile weir by more than
36、 1 %. The range of level measurement of the gauge will determine the distance of the first baffle downstream from the crest. However if the range is set too high, the first baffle will be set so far downstream that fish will not be able to pass over the final section of low depth and high velocity f
37、low. The solution was tested in the laboratory with structures that operate up to a maximum head of 0,49 m at field scale. It is recommended that the first baffle should not be set any further downstream than a distance equivalent to a maximum head of 0,49 m. ISO 2016 All rights reserved 3 ISO/TR 19
38、234:2016(E) a) Baffles installed on a weir shown under dry conditions b) Flow condition on a weir with baffles under running condition Figure 1 Examples of baffle installations on triangular profile weirs 6 Installation 6.1 Site selection and application 6.1.1 Restriction The baffle application is r
39、estricted to the use on two dimensional triangular profile flow gauging weirs as set out in ISO 4360; on weirs with a downslope 1:5 (Vertical: Horizontal) (20 % gradient in percentage or 11,31 degrees slope with horizontal). 6.1.2 Background The technique was originally developed to improve fish pas
40、sage on triangular profile gauging weirs but also addressed gradients up to 1:4 (25 %, 14 degrees) Baffles can be fitted to both single and compound triangular profile weirs. In the case of compound structures, the baffles are normally fitted to the lowest weir structure. Where there are two lower w
41、eir structures at the same level, consideration should be given to using the structure that has better access for maintenance and/or is least likely to be affected by debris. 6.1.3 Preliminary survey A preliminary survey should be made of the physical and hydraulic features of the site, to check tha
42、t it conforms (or can be made to conform) to the requirements necessary for baffle installation. Particular attention should be paid to the following features for gauging weirs. a) The downstream slope is confirmed as being nominally a 1:5 slope. b) The concrete face of the slope should be smooth an
43、d in good condition without signs of spalling, cracking or leaks. c) Knowledge of the location and depth of reinforcement bars in the concrete, if present, is advantageous.4 ISO 2016 All rights reserved ISO/TR 19234:2016(E) d) The mean approach velocity in the downstream stilling basin or natural ri
44、ver channel should be no more than those given in Table 1 at Q 10for migratory salmonids; Q 20for brown trout, grayling, and coarse fish; and Q 70for eels. e) Where present, the tailwater stilling basin should be a minimum of 3,0 m in length downstream from any truncation, or from the bottom of the
45、weir slope. f) Where present, the stilling basin should have a minimum depth of 0,3 m below tail river bed level. g) Where no stilling basin is present, there should be a minimum depth of 0,3 m for 3 m distance immediately downstream from any truncation, or from the bottom of the weir slope and the
46、water velocities should not exceed those given in (d) above. h) Where the downstream face is truncated and forms a vertical drop to the downstream stilling basin or river bed, additional works may be required to extend the downstream slope to achieve the appropriate baffle layout see (i) below. i) A
47、 truncated weir (for hydrometric purposes) may be used downstream of the last baffle where salmonids are the only species present. Where other species are present, the downslope should continue to the floor from the stilling basin, but may be at a maximum slope of 1:2 beyond the last baffle. j) The
48、water level on the downstream side of the most downstream low cost baffle should be such that streaming flow occurs in the free slot (for 0,2 m baffles this means 0,12 m of water, i.e. H 2 /H 1 0,60) at Q 95exceedance. Table 1 Maximum acceptable mean approach velocities in the stilling basin for dif
49、ferent fish species Migratory salmonids Brown trout and graylings Coarse fish Eels Mean approach velocity in stilling basin, m/s 1,0 0,7 0,5 0,3 If the site does not possess the characteristics necessary for satisfactory installation, the site should be rejected unless suitable improvements are practicable to achieve those characteristics. Key 1 downstream water level at Q 95 2 downstream bed level 3 stilling basin Figure 2 Sketch illustrating the definition of structural head difference (SHD) ISO 2016 All rig
