Significance and Use
This test method is particularly useful for determining the discharge when it cannot be measured directly by some type of current meter to obtain velocities and with sounding weights to determine the cross section.
Even under optimum conditions, the personnel available cannot cover all points of interest during a major flood. Field personnel cannot always obtain reliable results by direct methods if the stage is rising or falling very rapidly, if flowing ice or debris interferes with depth or velocity measurements.
Under the worst conditions, access roads are blocked, cableways and bridges may be washed out, and knowledge of the flood frequently comes too late to obtain direct measurements of flow. Therefore, some type of indirect measurement is necessary. The slope-area method is a commonly used method.
1.1 This test method covers the computation of discharge (the volume rate of flow) of water in open channels or streams using representative cross-sectional characteristics, the water-surface slope, and coefficient of channel roughness as input to gradually-varied flow computations.
1.2 This test method produces an indirect measurement of the maximum discharge for one flow event, usually a specific flood. The computed discharge may be used to help define the high-water segment of a stage-discharge relation.
1.3 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.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1129 Terminology Relating to Water
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
D3858 Test Method for Open-Channel Flow Measurement of Water by Velocity-Area Method
ISO1070 Liquid Flow Measurements in Open Channels--Slope-Area Method
flood; open channel flow; water discharge; Bridge studies; Channel roughness; Cross section data/analysis--water; Discharge measurement; Field testing--water; Floods; Indirect flow/discharge measurement; Open channel flow--water; Slope-area method; Transit-stadia survey; Water analysis; Water discharge/velocity; Water-surface profiles
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Citing ASTM Standards
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