1.1 本规程涵盖了将水位（高程）与流量相关的曲线的制定。已记录了测量流量和测量水位的标准试验方法（见规程 D3858 ，和测试方法 D5129 , D5130 , D5243 , D5388 和 D5413 ). 本规程采用每种测试方法确定的流量和阶段，并使用曲线显示它们之间的关系。这条曲线被称为水位流量关系或额定值曲线。 1.2 本规程中描述的程序通常由负责流量调查的人员使用，例如美国。 美国地质调查局、陆军工程兵团、垦务局和美国农业研究局。这些程序大多改编自美国地质调查局的报告。 2. , 3. 1.3 本规程中描述的程序仅适用于简单自由流动的明渠流。没有描述使用多级输入的极低坡度渠道、受人为调节影响的渠道或潮汐条件的复杂水力条件的额定值。脚注2和脚注3中列出的文件详细描述了这些类型的评级。 2. , 3. 1.4 该实践使用电流表放电测量或间接放电测量的结果以及相应的测量阶段来定义尽可能多的阶段-放电关系曲线。针对整个水位和流量范围开发了一条理论曲线，以形成曲线。 1.5 以英寸磅为单位的数值应视为标准。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 这种做法对于在测量站或重复需要流量信息的位置确定流量特别有用。 5.2 本规程仅适用于明渠水流条件，其中明渠水力学允许水位和流量之间存在稳定关系。

1.1 This practice covers the development of a curve relating stage (elevation) to discharge. Standard test methods have been documented for measuring discharge and for measuring stage (see Practice D3858 , and Test Methods D5129 , D5130 , D5243 , D5388 , and D5413 ). This practice takes the discharge and stage determined by each respective test method and shows a relation between them using a curved line. This curved line is called a stage-discharge relation or rating curve. 1.2 The procedures described in this practice are used commonly by those responsible for investigations of streamflow, for example, the U.S. Geological Survey, Army Corps of Engineers, Bureau of Reclamation, and U.S Agriculture Research Service. For the most part, these procedures are adapted from reports of the U.S. Geological Survey. 2 , 3 1.3 The procedures described in this practice apply only to simple freely flowing open-channel flow. Ratings for complex hydraulic conditions of extremely low slope channels using multiple-stage inputs, channels affected by man-induced regulation, or tidal conditions are not described. These types of ratings are described in detail in the documents listed in Footnotes 2 and 3. 2 , 3 1.4 This practice uses the results of current-meter discharge measurements or indirect discharge measurements and the corresponding measured stage to define as much of the stage-discharge relation curve as possible. A theoretical curve is developed for the full range of stage and discharge to shape the curve. 1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.6 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This practice is particularly useful for determining the discharge at a gauging station or a location where discharge information is repeatedly needed. 5.2 This practice is applicable only for open-channel flow conditions where channel hydraulics permit a stable relation between stage and discharge.