ASTM D1941-91(2013)

Standard Test Method for Open Channel Flow Measurement of Water with the Parshall Flume

SIGNIFICANCE AND USE
5.1 Flume designs are available for throat sizes of 1 in. (2.54 cm) to 50 ft (15.2 m) which cover maximum flows of 0.2 to 3000 ft3/s (0.0057 to 85 m3/s) (1) and (2)4. They can therefore be applied to a wide range of flows, with head losses that are moderate.  
5.2 The flume is self-cleansing for moderate solids transport and therefore is suited for wastewater and flows with sediment.
SCOPE
1.1 This test method covers measurement of the volumetric flowrate of water and wastewater in open channels with the Parshall flume.  
1.1.1 Information related to this test method can be found in ISO 1438 and ISO 4359.  
1.2 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-2012
• ICS: 13.060.30 - Sewage water
• Technical Committee: D19 - Water
• Drafting Committee: D19.07 - Sediments, Geomorphology, and Open-Channel Flow

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D1941 −91 (Reapproved 2013)
Standard Test Method for
Open Channel Flow Measurement of Water with the Parshall
1
Flume
This standard is issued under the fixed designation D1941; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ISO 4359 Liquid Flow Measurement in Open Channels—
Rectangular Trapezoidal and U-shaped Flumes
1.1 This test method covers measurement of the volumetric
flowrate of water and wastewater in open channels with the
3. Terminology
Parshall flume.
3.1 Definitions—For definitions of terms used in this test
1.1.1 Information related to this test method can be found in
method, refer to Terminology D1129.
ISO 1438 and ISO 4359.
1.2 This standard does not purport to address all of the 3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the 3.2.1 free flow—a condition where the flowrate is governed
by the state of flow at the crest overfall and hence can be
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- determined from a single upstream depth measurement.
mine the applicability of regulatory limitations prior to use.
3.2.2 head—the height of a liquid above a specified point;
1.3 This international standard was developed in accor-
that is, the flume crest.
dance with internationally recognized principles on standard-
3.2.3 hydraulic jump—an abrupt transition from supercriti-
ization established in the Decision on Principles for the
caltosubcriticalflow,accompaniedbyconsiderableturbulence
Development of International Standards, Guides and Recom-
or gravity waves, or both.
mendations issued by the World Trade Organization Technical
3.2.4 normal depth—the uniform depth of flow for a given
Barriers to Trade (TBT) Committee.
flowrate in a long open channel of specific shape, roughness,
2. Referenced Documents and slope.
2
3.2.5 primary instrument—the device (in this case, the
2.1 ASTM Standards:
flume) that creates a hydrodynamic condition that can be
D1129 Terminology Relating to Water
sensed by the secondary instrument.
D2777 Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
3.2.6 scow float—an in-stream flat for depth sensing usually
D3858 Test Method for Open-Channel Flow Measurement
mounted on a hinged cantilever.
of Water by Velocity-Area Method
3.2.7 secondary instrument—in this case, a device which
3
2.2 ISO Standards:
measures the depth of flow at an appropriate location in the
ISO 555 Liquid Flow Measurements in Open Channels—
flume. The secondary instrument may also convert the mea-
Dilution Methods for Measurement of Steady Flow—
sured depth to an indicated flow rate.
Constant Rate Injection Method
3.2.8 stilling well—a small reservoir connected through a
ISO 1438 Liquid Flow Measurement in Open Channels
constricted passage to the main channel, that is, the flume, so
Using Thin-Plate Weirs and Venturi Flumes
that a depth measurement can be made under quiescent
conditions.
1
This test method is under the jurisdiction of ASTM Committee D19 on Water
3.2.9 subcritical flow—open channel flow at a velocity less
and is the direct responsibility of Subcommittee D19.07 on Sediments,
than the velocity of gravity waves in the same depth of water.
Geomorphology, and Open-Channel Flow.
Current edition approved Jan. 1, 2013. Published January 2013. Originally Subcritical flow is affected by downstream conditions, since
approved in 1962. Last previous edition approved in 2007 as D1941 – 91 (2007).
disturbances are able to travel upstream.
DOI: 10.1520/D1941-91R13.
2
3.2.10 submerged flow—a condition where the water stage
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
downstream of the flume is sufficiently high to affect the flow
Standards volume information, refer to the standard’s Document Summary page on
over the flume crest and hence the free-flow depth-discharge
the ASTM website.
3
relation no longer applies and discharge depends on two head
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. measurements.
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D1941−91 (2013)
3.2.11 supercritical flow—open channel flow at a velocity
greater than that of gravity waves in the same depth, so
disturbances cannot travel upstream, and
...