ASTM D4050-96(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4050–96 (Reapproved 2002)
Standard Test Method
(Field Procedure) for Withdrawal and Injection Well Tests for
Determining Hydraulic Properties of Aquifer Systems
This standard is issued under the fixed designation D 4050; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 4750 Test Method for Determining Subsurface Liquid
Levels in a Borehole or Monitoring Well (Observation
1.1 This test method describes the field procedure for
Well)
selecting well locations, controlling discharge or injection
rates, and measuring water levels used to analyze the hydraulic
3. Terminology
properties of an aquifer or aquifers and adjacent confining
3.1 Definitions:
beds.
3.1.1 aquifer, confined—an aquifer bounded above and
1.2 This test method is used in conjunction with an analyti-
below by confining beds and in which the static head is above
cal procedure such as Test Methods D 4105 or D 4106 to
the top of the aquifer.
determine aquifer properties.
3.1.2 confining bed—a hydrogeologic unit of less perme-
1.3 The appropriate field and analytical procedures are
able material bounding one or more aquifers.
selected as described in Guide D 4043.
3.1.3 control well—well by which the head and flow in the
1.4 The values stated in SI units are to be regarded as
aquifer is changed, for example, by pumping, injection, or
standard.
change of head.
1.5 This standard does not purport to address all of the
3.1.4 hydraulic conductivity (field aquifer tests)—the vol-
safety concerns, if any, associated with its use. It is the
ume of water at the existing kinematic viscosity that will move
responsibility of the user of this standard to establish appro-
in a unit time under a unit hydraulic gradient through a unit
priate safety and health practices and determine the applica-
area measured at right angles to the direction of flow.
bility of regulatory limitations prior to use.
3.1.5 observation well—a well open to all or part of an
2. Referenced Documents aquifer.
3.1.6 piezometer—a device used to measure hydraulic head
2.1 ASTM Standards:
at a point in the subsurface.
D 653 Terminology Relating to Soil, Rock, and Contained
3.1.7 specific storage—the volume of water released from
Fluids
ortakenintostorageperunitvolumeoftheporousmediumper
D 2488 Practice for Description and Identification of Soils
unit change in head.
(Visual-Manual Procedure)
3.1.8 storage coeffıcient —the volume of water an aquifer
D 4043 Guide for Selection of Aquifer-Test Method in
releases from or takes into storage per unit surface area of the
Determining Hydraulic Properties by Well Techniques
aquifer per unit change in head. For a confined aquifer, the
D 4105 Test Method (Analytical Procedure) for Determin-
storagecoefficientisequaltotheproductofthespecificstorage
ing Transmissivity and Storage Coefficient of Nonleaky
and aquifer thickness. For an unconfined aquifer, the storage
Confined Aquifers by the Modified Theis Nonequilibrium
coefficient is approximately equal to the specific yield.
Method
3.1.9 transmissivity—the volume of water at the existing
D 4106 Test Method (Analytical Procedure) for Determin-
kinematic viscosity that will move in a unit time under a unit
ing Transmissivity and Storage Coefficient of Nonleaky
hydraulic gradient through a unit width of the aquifer.
Confined Aquifers by the Theis Nonequilibrium Method
3.1.10 For definitions of other terms used in this test
method, see Terminology D 653.
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
4. Summary of Test Method
Rock and is the direct responsibility of Subcommittee D18.21 on GroundWater and
Vadose Zone Investigations.
4.1 This test method describes the field practices in con-
Current edition approved Oct. 10, 1996. Published February 1997. Originally
ducting withdrawal and injection well tests. These methods
published as D 4050 – 91.
Annual Book of ASTM Standards, Vol 04.08. involve withdrawal of water from or injection of water to an
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4050
aquifer through a control well and measurement of the water- 6.5 Many aquifer tests are made at “sites of opportunity,”
level response in the aquifer. The analysis of the data from this that is, using existing production wells as the control well and
field practice is described in standards such as Test Methods using other existing wells for observation of water level. In
D 4105 and D 4106. such cases the locations and screened intervals of the wells
should be compatible with the requirements of the method of
5. Significance and Use test analysis.
6.6 Water-Level Measurement Equipment—Manual mea-
5.1 Withdrawal and injection well test field procedures are
surements can be made with a steel tape or electric tape as
used with appropriate analytical procedures in appropriate
described in Test Method D 4750, with a mechanical recorder
hydrogeological sites to determine transmissivity and storage
linked to a float, or combination of pressure transducer and
coefficient of aquifers and hydraulic conductivity of confining
electronic data logger.
beds.
6.6.1 Mechanical Recorders—Mechanical recorders em-
ploy a float in the well to produce a graphic record of water
6. Apparatus
levelchanges.Earlyinthetest,itmaybedifficulttodistinguish
6.1 Various types of equipment can be used to withdraw or
small increments of time on the recorder chart, therefore the
inject water into the control well, measure withdrawal and
recorder should be supplemented with additional early time
injection rates, and measure water levels. The test procedure
measurements or by marking the trace of an automatic water-
may be conducted with different types of equipment to achieve
level recorder chart and recording the time by the mark. Check
similar results. The objectives to be achieved by the use of the
the mechanical recorder periodically throughout the test using
equipment are given in this section and in Sections 7 and 8.
the steel tape.
6.2 Control Well—Discharge or injection well test methods
6.6.2 Pressure Transducers and Electronic Data
require that water be withdrawn from or injected into a single
Loggers—A combination of a pressure transducer and elec-
well. This well, known as the control well, must be drilled and
tronic data logger can provide rapid measurements of water-
completed such that it transmits water to or from the aquifer
level change, and can be programmed to sample at reduced
(usually the entire thickness of the aquifer) at rates such that a
frequency late in the test. Select the pressure transducer to
measurable water level change will occur at observation wells.
measure pressure changes equivalent to the range of expected
Thecontrolwellshouldbeasefficientaspossible,toreducethe
water level changes. Check the transducer in the field by
head loss between the aquifer and the well. Well development
raising and lowering the transducer a measured distance in the
should be as complete as possible to eliminate additional
well. Also check the transducer readings periodically with a
production of sand or silt and consequent changes in well
steel tape.
efficiency and pumping water levels during the test. The
cuttings from the control well should be described and re-
7. Conditioning
corded according to Practice D 2488. The analytical method
7.1 Pre-Test Procedures:
selectedforanalysisofthedatamayspecifycertaindimensions
7.1.1 Selecting Aquifer-Test Method—Develop a conceptual
of the control well such as screen length and depth of screen
model of the site hydrogeology and select the appropriate
placement. Specific requirements for control wells may be
given in standards for specific analytical methods (see, for aquifer test method according to Guide D 4043. Observe the
requirements of the selected test method with regard to
example, Test Methods D 4105 and D 4106).
specifications for the control well and observations wells.
6.3 Observation Wells or Piezometers—Numbers of obser-
vation wells and their distance from the control well and their 7.1.2 Field Reconnaissance—Make a field reconnaissance
screened interval may be dependent upon the test method to be of the site before conducting the test to include as much detail
employed. Refer to the analytical test method to be used for as possible on depth, continuity, extent, and preliminary
specifications of observation wells (see, for example, Test estimates of the hydrologic properties of the aquifers and
Methods D 4105 and D 4106). confining beds. Note the location of existing wells and water-
6.4 Control Well Pump—A pump capable of withdrawal of holding or conveying structures that might interfere with the
test. The control should be equipped with a pipeline or
a constant or predetermined variable rate of water from the
control well. The pump and motor should be adequately sized conveyancestructureadequatetotransmitthewaterawayfrom
the test site, so that recharge is not induced near the site. Make
for the designed pumping rate and lift. The pump or motor
arrangements to ensure that nearby wells are turned off well
mustbeequippedwithacontrolmechanismtoadjustdischarge
before the test, and automatic pump controls are disabled
rate. In the case of diesel-, gasoline-, or natural-gas-fueled
throughout the anticipated test period. Alternately, it may be
engines, throttle settings should allow for small adjustments in
necessary to pump some wells throughout the test. If so, they
pumping rates. Pumps equipped with electric motors are
should be pumped at a constant rate, and not started and
usually con
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