ASTM D5786-95(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D5786 − 95(Reapproved 2006)
Standard Practice for
(Field Procedure) for Constant Drawdown Tests in Flowing
Wells for Determining Hydraulic Properties of Aquifer
Systems
This standard is issued under the fixed designation D5786; 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 D653 Terminology Relating to Soil, Rock, and Contained
Fluids
1.1 This practice covers the methods for controlling draw-
D4043 Guide for Selection of Aquifer Test Method in
down and measuring discharge rates and head to analyze the
Determining Hydraulic Properties by Well Techniques
hydraulic properties of an aquifer or aquifers.
D4750 Test Method for Determining Subsurface Liquid
1.2 This practice is used in conjunction with analytical
Levels in a Borehole or Monitoring Well (Observation
procedures such as those of Jacob and Lohman (1)/(2), and 4
Well) (Withdrawn 2010)
Hantush (3)/(4).
3. Terminology
1.3 The appropriate field and analytical procedures for
determining hydraulic properties of aquifer systems are se-
3.1 Definitions—For definitions of terms used in this
lected as described in Guide D4043.
practice, see Terminology D653.
1.4 This standard does not purport to address all of the
4. Summary of Practice
safety concerns, if any, associated with its use. It is the
4.1 This practice describes the field procedures for conduct-
responsibility of the user of this standard to establish appro-
ing an aquifer test on a well that is flowing, that is, the head in
priate safety and health practices and determine the applica-
the well remains above the top of the well casing. This method
bility of regulatory limitations prior to use.
involves inducing a constant drawdown and measuring the
1.5 This practice offers a set of instructions for performing
varying discharge rate from the control well.
one or more specific operations. This document cannot replace
education or experience and should be used in conjunction
5. Significance and Use
withprofessionaljudgment.Notallaspectsofthispracticemay
be applicable in all circumstances. This ASTM standard is not
5.1 Constant drawdown test procedures are used with ap-
intended to represent or replace the standard of care by which
propriate analytical procedures to determine transmissivity,
the adequacy of a given professional service must be judged, hydraulic conductivity, and storage coefficient of aquifers.
nor should this document be applied without consideration of
6. Apparatus
a project’s many unique aspects. The word “Standard” in the
title of this document means only that the document has been
6.1 Various types of equipment can be used to measure the
approved through the ASTM consensus process.
flow rate of the well. The equipment shall be sized so that it
does not constrict the flow rate from the well.
2. Referenced Documents
6.2 An apparatus shall be placed on the control well
2.1 ASTM Standards:
discharge line such that the well can be shut in to prevent flow
prior to conducting this field procedure and so that the
apparatus will not constrict flow from the well when it is
This practice is under the jurisdiction of ASTM Committee D18 on Soil and
Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and
allowed to flow.
Vadose Zone Investigations.
6.3 Head measurements can be made using one of the
Current edition approved July 1, 2006. Published July 2006. Originally approved
in 1995. Last previous edition approved in 2000 as D5786 – 95 (2000). DOI:
following apparatuses:
10.1520/D5786-95R06.
6.3.1 Standpipe—A pipe or piece of well casing may be
The boldface numbers in parentheses refer to a list of references at the end of
installed to extend above the elevation of the discharge. This
this standard.
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 last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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D5786 − 95 (2006)
standpipe will also extend above the elevation of the head in wells are flowing, measure their response in a manner similar
the control well. This standpipe will allow for direct measure- to that described for the control well. Redevelop wells or
ment of the water level following methods described in Test piezometers with unusually sluggish response.
Method D4750. 7.1.6 Measure the pressure head in the shut-in control well
6.3.2 Pressure Measurement—A pressure gauge (mechani- and observation wells (if any) to determine the trend of water
cal gage, manometer, or pressure transducer) may be installed levelsbeforethecommencementofthetest.Thisperiodshould
below the shut-in mechanism in the control well. Determine be at least equal to the length of the flowing portion of the test.
theheadelevationbyaddingthepressurereading(expressedin
7.2 Test Procedure:
the height of the water) to the elevation of the sensor of the
7.2.1 Based on pretesting results and the conceptual model
pressure gage.
of the site (see Guide D4043), select the duration of the test.
6.4 Control Well—This practice requires that water flow 7.2.2 Shut in the Control Well—Completely stop flow from
from a single well. This well, known as the control well, shall the control well prior to conducting the test for a period at least
be drilled and completed such that it transmits water from the as long as the anticipated duration of the flowing portion of the
aquifer (usually the entire thickness of the aquifer) as effi- test.
ciently as possible to reduce head loss between the aquifer and 7.2.3 Discharge from Control Well—Allow the control well
to flow at a variable rate. The flow rate will vary naturally to
the well. Well development should be as complete as possible
to eliminate additional production of sediments (aquifer par- maintain a constant drawdown at the control well.
7.2.4 Measure Discharge Rate—Measure and record the
ticles or drill cuttings) and consequent changes in well effi-
ciency during the test. discharge rate frequently during the early phase of discharge;
increase the interval between measurements in a logarithmic
7. Procedure manner as pumping continues.
7.1 Pretest Procedures: NOTE 1—Table 1 presents a suggested frequency of discharge measure-
ments.
7.1.1 Select Aquifer Test Method—Develop a con
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