ASTM D5850-95(2012)
(Test Method)Standard Test Method for (Analytical Procedure) Determining Transmissivity, Storage Coefficient, and Anisotropy Ratio from a Network of Partially Penetrating Wells
Standard Test Method for (Analytical Procedure) Determining Transmissivity, Storage Coefficient, and Anisotropy Ratio from a Network of Partially Penetrating Wells
SIGNIFICANCE AND USE
5.1 This test method is one of several available for determining vertical anisotropy ratio. Among other available methods are Weeks ((5); see Test Method D5473), that relies on distance-drawdown data, and Way and McKee (6), that utilizes time-drawdown data. An important restriction of the Weeks distance-drawdown method is that the observation wells must have identical construction (screened intervals) and two or more of the observation wells must be located at a distance from the pumped well beyond the effects of partial penetration. The procedure described in this test method general distance-drawdown method, in that it works in theory for any observation well configuration incorporating three or more wells, provided some of the wells are within the zone where flow is affected by partial penetration.
5.2 Assumptions:
5.2.1 Control well discharges at a constant rate, Q.
5.2.2 Control well is of infinitesimal diameter and partially penetrates the aquifer.
5.2.3 Data are obtained from a number of partially penetrating observation wells, some screened at elevations similar to that in the pumped well and some screened at different elevations.
5.2.4 The aquifer is confined, homogeneous and areally extensive. The aquifer may be anisotropic, and, if so, the directions of maximum and minimum hydraulic conductivity are horizontal and vertical, respectively.
5.2.5 Discharge from the well is derived exclusively from storage in the aquifer.
5.3 Calculation Requirements—Application of this method is computationally intensive. The function, fs, shown in (Eq 4) must be evaluated numerous times using arbitrary input parameters. It is not practical to use existing, somewhat limited, tables of values for fs and, because this equation is rather formidable, it is not readily tractable by hand. Because of this, it is assumed the practitioner using this test method will have available a computerized procedure for evaluating the function fs. This can be accomplished ...
SCOPE
1.1 This test method covers an analytical procedure for determining the transmissivity, storage coefficient, and ratio of vertical to horizontal hydraulic conductivity of a confined aquifer using observation well drawdown measurements from a constant-rate pumping test. This test method uses data from a minimum of four partially penetrating, properly positioned observation wells around a partially penetrating control well.
1.2 The analytical procedure is used in conjunction with the field procedure in Test Method D4050.
1.3 Limitations—The limitations of the technique for determination of the horizontal and vertical hydraulic conductivity of aquifers are primarily related to the correspondence between the field situation and the simplifying assumption of this test method.
1.4 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.5 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
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Standards Content (Sample)
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Designation: D5850 − 95 (Reapproved 2012)
Standard Test Method for (Analytical Procedure)
Determining Transmissivity, Storage Coefficient, and
Anisotropy Ratio from a Network of Partially Penetrating
1
Wells
This standard is issued under the fixed designation D5850; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Properties of Aquifer Systems
D5473Test Method for (Analytical Procedure for) Analyz-
1.1 This test method covers an analytical procedure for
ing the Effects of Partial Penetration of Control Well and
determining the transmissivity, storage coefficient, and ratio of
Determining the Horizontal and Vertical Hydraulic Con-
vertical to horizontal hydraulic conductivity of a confined
ductivity in a Nonleaky Confined Aquifer
aquifer using observation well drawdown measurements from
a constant-rate pumping test. This test method uses data from
3. Terminology
a minimum of four partially penetrating, properly positioned
observation wells around a partially penetrating control well.
3.1 Definitions:
3.1.1 aquifer, confined—an aquifer bounded above and be-
1.2 Theanalyticalprocedureisusedinconjunctionwiththe
lowbyconfiningbedsandinwhichthestaticheadisabovethe
field procedure in Test Method D4050.
top of the aquifer.
1.3 Limitations—The limitations of the technique for deter-
3.1.2 confining bed—ahydrogeologicunitoflesspermeable
mination of the horizontal and vertical hydraulic conductivity
material bounding one or more aquifers.
ofaquifersareprimarilyrelatedtothecorrespondencebetween
the field situation and the simplifying assumption of this test
3.1.3 control well—well by which the head and flow in the
method.
aquifer is changed, for example, by pumping, injection, or
imposing a constant change of head.
1.4 The values stated in inch-pound units are to be regarded
as the standard. The SI units given in parentheses are for
3.1.4 drawdown—vertical distance the static head is low-
information only.
ered due to the removal of water.
1.5 This standard does not purport to address all of the
3.1.5 hydraulic conductivity—(fieldaquifertest)thevolume
safety concerns, if any, associated with its use. It is the
of water at the existing kinematic viscosity that will move in a
responsibility of the user of this standard to establish appro-
unit time under a unit hydraulic gradient through a unit area
priate safety and health practices and determine the applica-
measured at right angles to the direction of flow.
bility of regulatory limitations prior to use.
3.1.6 observation well—a well open to all or part of an
2. Referenced Documents aquifer.
2
2.1 ASTM Standards: 3.1.7 piezometer—a device so constructed and sealed as to
D653Terminology Relating to Soil, Rock, and Contained measure hydraulic head at a point in the subsurface.
Fluids
3.1.8 storage coeffıcient—the volume of water an aquifer
D4050Test Method for (Field Procedure) for Withdrawal
releases from or takes into storage per unit surface area of the
and Injection Well Testing for Determining Hydraulic
aquifer per unit change in head.
3.1.9 transmissivity—the volume of water at the existing
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
kinematic viscosity that will move in a unit time under a unit
Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and
hydraulic gradient through a unit width of the aquifer.
Vadose Zone Investigations.
Current edition approved May 1, 2012. Published December 2012. Originally
3.1.10 For definitions of other terms used in this test
approved in 1995. Last previous edition approved in 2006 as D5850–95 (2006).
method, see Terminology D653.
DOI: 10.1520/D5850-95R12.
2 3.2 Symbols and Dimensions:
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
3.2.1 A—K /K , anisotropy ratio [nd].
z r
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.2.2 b—thickness of aquifer [L].
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D5850 − 95 (2012)
1/2
3.2.3 C —drawdown correction factor, equal to the ratio of gible at a distance of about 1.5b/(K /K ) . This test method
f z r
the drawdown for a fully penetrating well network to the relies on obtaining drawdown measurements at a minimum of
drawdown for a partially penetrating well network (W(u)/ two locations within this distance of the pumped well and at
(W(u) + f )). each location obtaining
...
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