ASTM_D_3858_-_95_2014.pdf

Designation:D385895(Reapproved 2014)Standard Test Method forOpen-Channel Flow Measurement of Water by Velocity-AreaMethod1This standard is issued under the fixed designation D3858;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of the volumerate of flow of water in open channels by determining the flowvelocity and cross-sectional area and computing the dischargetherefrom(Refs(1-7).21.2 The procedures described in this test method are widelyused by those responsible for the collection of streamflow data,for example,the U.S.Geological Survey,Bureau ofReclamation,U.S.Army Corps of Engineers,U.S.Departmentof Agriculture,Water Survey Canada,and many state andprovincial agencies.The procedures are generally from internaldocuments of the above listed agencies,which have becomethe defacto standards as used in North America.1.3 This test method covers the use of current meters tomeasure flow velocities.Discharge measurements may bemade to establish isolated single values,or may be made in setsor in a series at various stages or water-level elevations toestablish a stage-discharge relation at a site.In either case,thesame test method is followed for obtaining field data andcomputation of discharge.1.4 Measurements for the purpose of determining the dis-charge in efficiency tests of hydraulic turbines are specified inInternational Electrotechnical Commission Publication 413forthe field acceptance tests of hydraulic turbines,and are notincluded in this test method.1.5 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:4D1129 Terminology Relating to WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD4409 Test Method for Velocity Measurements of Water inOpen Channels with Rotating Element Current MetersD5089 Test Method for Velocity Measurements of Water inOpen Channels with Electromagnetic Current Meters2.2 ISO Standard:5ISO 3455(1976)Calibration of Rotating-Element CurrentMeters in Straight Open Tanks3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 current meteran instrument used to measure,at apoint,velocity of flowing water.3.2.2 dischargethe volume of flow of water through across section in a unit of time,including any sediment or othersolids that may be dissolved in or mixed with the water.3.2.3 floata buoyant article capable of staying suspendedin or resting on the surface of a fluid;often used to mark thethread or trace of a flow line in a stream and to measure themagnitude of the flow velocity along that line.3.2.4 stagethe height of a water surface above an estab-lished(or arbitrary)datum plane;also termed gage height.4.Summary of Test Method4.1 The principal of this test method consists in effectivelyand accurately measuring the flow velocity and cross-sectional1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.07 on Sediments,Geomorphology,and Open-Channel Flow.Current edition approved Jan.1,2014.Published January 2014.Originallyapproved in 1979.Last previous edition approved in 2008 as D3858 95(2008).DOI:10.1520/D3858-95R14.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3Available from International Electrotechnical Commission(IEC),3,rue deVaremb,P.O.Box 131,CH-1211 Geneva 20,Switzerland,http:/www.iec.ch.4For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.5Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 area of an open channel or stream.The total flow or dischargemeasurement is the summation of the products of partial areasof the flow cross section and their respective average veloci-ties.The equation representing the computation is:Q 5(av!where:Q=total discharge,a=individual partial cross-sectiona