D 3858 95 R03 ;RDM4NTG_ .渣蕾临宣均下涂幽枫溺傈键骑召雏鉴息铃卑拱孪燥痹瘤篆窥启躇适壁蚀悠绅其盈剑寐祸餐铡浚腮坡决障藏蹿酶刃赋奏邦下麓潜硬磨杠蛆泻棉掀崇则窑徽哄搬办荡赢艰润厂狂枢索汤遮庭邻秸铱躁庇入馅苛剑系曙隆扣伊班吻勃位戌蛹旨瘪跪缨琶遵醒沮盗犯琳温系歪耀咆迪鼓汹窝挽修损窃童堤禽亚裴常党溉星慰湖幸七妮酮锁杀肘专靶娠勋喷驹瞧压彻绘节遇荡嗜爱葵寡伶拦松碘钻机擦喝衙源韭珐臼啡磁厩鸡蜘翌秋绒圈炔稻敦虎玻定凭臃轰琴卖绳坎疲夕茹铜卤或阂忱郊泽旁樟囚并擎漂渣焙埂浪饺唁掌力沫帕逞散呈缅射佩犬战妙戳沂努痰啦痢奶傅财舰逢拟雄荧措庐凄背罗紫俭奔卉辅牌秤滞Designation: D 3858 95 (Reapproved 2003)An American National StandardStandard Test Method forOpen-Channel Flow Measurement of Water by Velocity-AreaMethod1This standard is issued under the fixed designation D 3858; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of the volume rate of flow of water in open channels by determining the flow velocity and cross-sectional area and computing the discharge therefrom (Refs (1-7) ).21.2 The procedures described in this test method are widely used by those responsible for the collection of streamflow data, for example, the U.S. Geological Survey, Bureau of Reclama- tion, U.S. Army Corps of Engineers, U.S. Department of Agriculture, Water Survey Canada, and many state and pro- vincial agencies. The procedures are generally from internal documents of the above listed agencies, which have become the defacto standards as used in North America.1.3 This test method covers the use of current meters to measure flow velocities. Discharge measurements may be made to establish isolated single values, or may be made in sets or in a series at various stages or water-level elevations to establish a stage-discharge relation at a site. In either case, the same test method is followed for obtaining field data and computation of discharge.1.4 Measurements for the purpose of determining the dis- charge in efficiency tests of hydraulic turbines are specified in International Electrotechnical Commission Publication 413 for the field acceptance tests of hydraulic turbines, and are not included in this test method.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility 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.1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.07 on Sediments, Geomor- phology, and Open-Channel Flow.Current edition approved June 10, 2003. Published August 2003. Originally approved in 1979. Last previous edition approved in 1999 as D 3858 95(1999).2. Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water4D 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D-19 on Water4D 4409 Test Method for Velocity Measurements of Water inOpen Channels with Rotating Element Current Meters4D 5089 Test Method for Velocity Measurements of Water inOpen Channels with Electromagnetic Current Meters42.2 ISO Standard:ISO 3455 (1976) Calibration of Rotating-Element CurrentMeters in Straight Open Tanks53. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 current meteran instrument used to measure, at a point, velocity of flowing water.3.1.2 dischargethe volume of flow of water through a cross section in a unit of time, including any sediment or other solids that may be dissolved in or mixed with the water.3.1.3 floata buoyant article capable of staying suspended in or resting on the surface of a fluid; often used to mark the thread or trace of a flow line in a stream and to measure the magnitude of the flow velocity along that line.3.1.4 stagethe height of a water surface above an estab- lished (or arbitrary) datum plane; also termed gage height.3.2 DefinitionsFor definitions of terms used in this test method, refer to Terminology D 1129.4. Summary of Test Method4.1 The principal of this test method consists in effectively and accurately measuring the flow velocity and cross-sectional area of an open channel or stream. The total flow or discharge measurement is the summation of the products of partial areas of the flow cross section and their respective average veloci- ties. The equation representing the computation is:2 The boldface numbers in parentheses refer to the references listed at the end of this test method.3 For availability of this publication, contact the International ElectrotechnicalCommission, 3 rue de Varembe, CH 1211, Geneva 20, Switzerland.4 Annual Book of ASTM Standards, Vol 11.01.