Significance and Use
5.1 Assumptions—Leaky Aquifer:
5.1.1 Drawdown (sW) in the control well is constant,
5.1.2 Well is infinitesimal diameter and fully penetrates aquifer,
5.1.3 The aquifer is homogeneous, isotropic, and areally extensive, and
5.1.4 The control well is 100 % efficient.
5.2 Assumptions—Nonleaky Aquifer:
5.2.1 Drawdown (sW) in the control well is constant,
5.2.2 Well is infinitesimal diameter and fully penetrates aquifer,
5.2.3 The aquifer is homogeneous, isotropic, and areally extensive,
5.2.4 Discharge from the well is derived exclusively from storage in the nonleaky aquifer, and
5.2.5 The control well is 100 % efficient.
5.3 Implications of Assumptions:
5.3.1 The assumptions are applicable to confined aquifers and fully penetrating control wells. However, this test method may be applied to partially penetrating wells where the method may provide an estimate of hydraulic conductivity for the aquifer adjacent to the open interval of the well if the horizontal hydraulic conductivity is significantly greater than the vertical hydraulic conductivity.
5.3.2 Values obtained for storage coefficient are less reliable than the values calculated for transmissivity. Storage coefficient values calculated from control well data are not reliable.
1.1 This test method covers an analytical solution for determining transmissivity and storage coefficient of a leaky or nonleaky confined aquifer. It is used to analyze data on the flow rate from a control well while a constant head is maintained in the well.
1.2 This analytical procedure is used in conjunction with the field procedure in Practice D5786.
1.3 Limitations—The limitations of this technique for the determination of hydraulic properties of aquifers are primarily related to the correspondence between field situation and the simplifying assumption of the solution.
1.4 Units—The values stated in either SI Units or inch-pound units are to be regarded separately as standard. The values 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 test method.
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.6 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D4043 Guide for Selection of Aquifer Test Method in Determining Hydraulic Properties by Well Techniques
D5786 Practice for (Field Procedure) for Constant Drawdown Tests in Flowing Wells for Determining Hydraulic Properties of Aquifer Systems
D6026 Practice for Using Significant Digits in Geotechnical Data
aquifers; aquifer tests; control wells; groundwater; observation wells; storage coefficient; transmissivity;
ICS Number Code 13.060.10 (Water of natural resources)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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