ASTM D5716/D5716M-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D5716/D5716M − 15 D5716/D5716M − 20
Standard Test Method for
Measuring the Rate of Well Discharge by Circular Orifice
Weir
This standard is issued under the fixed designation D5716/D5716M; 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*
1.1 This test method covers construction and operation of a circular orifice weir for measuring the discharge from a well. This
test method is a part of a series of standards prepared on the in situ determination of hydraulic properties of aquifer systems by
single- or multiple-well tests. Selection of a well discharge measurement test method is described in Guide D5737D5737M.
1.2 The discharge rate determined by this test method is commonly used for a number of aquifer test methods and to provide
information for the evaluation of well and pump performance.
1.3 Limitations—This test method is limited to the description of a method common to hydraulic engineering for the purpose
of groundwater discharge measurement in temporary or test conditions.
1.4 Much of the information presented in this test method is based on work performed by the Civil Engineering Department
of Purdue University during the late 1940s. The essentials of that work have been presented in a pamphlet prepared by
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Layne-Bowler, Inc. and updated by Layne Western Company, Inc.
1.5 All observed and calculated values shall be conform to the guidelines for significant digits and rounding established in
Practice D6026.
1.5.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry
standard. In addition they are representative of the significant digits that should generally be retained. The procedures used do not
consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives;
and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations.
It is beyond the scope of this document to consider significant digits sused analysis methods for engineering design.
1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated
in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values
from the two systems may result in non-conformance with the standard. Reporting of test results in units other than SI shall not
be regarded as nonconformance with this standard.
1.7 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.8 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.
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and Vadose
Zone Investigations.
Current edition approved Nov. 1, 2015June 1, 2020. Published December 2015June 2020. Originally approved in 1995. Last previous edition approved in 20062015 as
D5716–95(2006)D5716, which was withdrawn July 2015 and reinstated in November 2015. DOI: 10.1520/D5716-15.–15. DOI: 10.1520/D5716_D5716M-20.
Measurement of Water Flow Through Pipe Orifice With Free Discharge, Bulletin 501, Layne-Bowler, Inc., Mission, KS, 1958.
Measurement of Water Flow Through Pipe Orifice With Free Discharge, Layne-Western Company, Inc., Mission, KS, 1988.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5716/D5716M − 20
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D5737D5737M Guide for Methods for Measuring Well Discharge
D6026 Practice for Using Significant Digits in Geotechnical Data
2.2 Other Documents:
GWPD 10 Estimating discharge from a pumping well by use of a circular orifice weir, United States Geological Survey
3. Terminology
3.1 Definitions:
3.1.1 For definitions of common technical terms used in this standard, refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 circular orifice weir—a circular restriction in a pipe that causes back pressure that can be measured in a piezometer tube.
3.2.1.1 Discussion—
Also called orifice tube and orifice meter.
3.3 Symbols and Dimensions Used in this Standard:
3.3.1 A—orifice plate open area [ L ].
3.3.2 C—coefficient of discharge for the orifice [nd].
−2
3.3.3 g—acceleration due to gravity [ LT ].
3.3.4 h—head in manometer [ L].
3 −1
3.3.5 Q—control well discharge [ L T ].
3.3.6 o—orifice diameter [ L].
3.3.7 d—pipe inside diameter [ L].
4. Summary of Test Method
4.1 This test method involves pumping a control well at a constant or variable rate through a circular orifice weir for a given
period of time. Discharge is through an orifice weir that allows determination of the discharge rate.
4.2
5. Significance and Use
5.1 This test method provides design information for construction of an orifice weir. It also describes setup, operation,
inspection, calculation of discharge, and reporting. The accuracy of a circular weir decreases at low flows. The use of a circular
orifice weir requires a constant flow velocity over the period of measurement. The results may be affected by the piezometers
distance from the orifice plate. This equipment may not be appropriate for measuring flows on small wells, or wells with limited
recharge.
5.2 Aquifer testing has been conducted for the purposes of production and pressure relief well design and water resource
assessment. Production wells are used for public and industrial water supplies, hydraulic controls, and groundwater capture.
Pressure relief wells are for hydraulic controls. Test wells are for the purpose of water resource assessment.
5.3 Discharge must also be known for certain methods to evaluate well and pump performance.
NOTE 1—Practice D3740 provides evaluation factors for the activities in this standard. The quality of the result produced by this standard is dependent
on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740
are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with
Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some
of those factors.
6. Apparatus
6.1 Construction of a Circular Orifice Weir—A construction diagram of a circular orifice weir is presented in Fig. 1. The
circular orifice is a hole located in the center of a plate attached to a straight horizontal length of discharge pipe. The pipe is at
least 1.8 m [6 ft] in length. Approximately 600 mm [24 in.] from the end plate and at least 1.2 m [4 ft] from the other end of the
discharge pipe, a piezometer is attached to the discharge pipe so that the head in the discharge pipe can be measured.
6.1.1 Orifice Plate—The orifice is a round hole with clean, square edges in the center of a circular steel plate. The plate must
be a minimum of 1.6 mm [ ⁄16 in.] thick around the circumference of the hole. The remaining thickness of the orifice should be
chamfered to 45° and with the chamfered edge down stream.
Driscoll, F. G., Ground Water and Wells, Johnson Division, St. Paul, MN, 1986, pp. 537–541.
D5716/D5716M − 20
FIG. 1 Construction of a Circular Orifice Weir
6.1.2 Discharge Pipe—The discharge pipe must be straight and level for a distance of at least 1.8 m [6 ft] before the water
reaches the orifice plate. This approach channel should be longer if possible. The end of the pipe must be cut squarely so the plate
will be vertical. The bore of the pipe should be smooth and free of any obstruction that might cause abnormal turbulence.
1 1
6.1.3 Piezometer—The discharge pipe wall is tapped midway between the top and bottom with a 3 mm [ ⁄8-in.] or 6 mm [ ⁄4-in.]
hole exactly 600 mm [24 in.] from the orifice plate. The manometer should be a distance of at least ten discharge pipe diameters
from the gate valve used to control pipe flow. Any burrs inside the pipe resulting from the drilling or tapping of the hole should
be filed off. A nipple is screwed into the tapped hole. The nipple must not protrude inside the discharge pipe. A clear plastic tube
1.2 to 1.5 m [4 or 5 ft] long is connected at one end to the nipple. A scale is fastened to a support so that the vertical distance from
the center of the discharge pipe up to the water level in the manometer can be measured. Alternately, a u-tube manometer or
pressure transducer may be used. During a test the manometer must be free of air bubbles.
6.2 The diameter of the orifice should be less than 80 % of the inside diameter of the approach channel pipe.
7. Procedure
7.1 Set up the apparatus as shown in Fig. 1 and Fig. 2. The apparatus should be set up so that the orifice pipe is horizontal and
the discharge is unimpeded. Use a combination of pipe and orifice diameter so that the anticipated head will be at least three times
the diameter of the orifice. The orifice plate must be vertical and centered in the discharge pipe.
7.2 Equipment should be inspected to minimize the pote
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