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ASTM D6170-97(2010)

(Guide)

Standard Guide for Selecting a Groundwater Modeling Code

Standard Guide for Selecting a Groundwater Modeling Code

SIGNIFICANCE AND USE
Groundwater modeling has become an important methodology in support of the planning and decision-making processes involved in groundwater management. Groundwater models provide an analytical framework for obtaining an understanding of the mechanisms and controls of groundwater systems and the processes that influence their quality, especially those caused by human intervention in such systems. Increasingly, models are an integral part of water resources assessment, protection, and restoration studies, and provide essential and cost-effective support for planning and screening of alternative policies, regulations, and engineering designs affecting groundwater.  
Many different groundwater modeling codes are available, each with their own capabilities, operational characteristics and limitations. Furthermore, each groundwater project has its own requirements with respect to modeling. Therefore, it is important that the most appropriate code is selected for a particular project. This is even more important for projects that require extensive modeling, or where costly decisions are based, in part, on the outcome of modeling-based analysis.
Systematic and comprehensive description of project requirements and code features provides the necessary basis for efficient selection of a groundwater modeling code. This standard guide is intended to encourage comprehensive and consistent description of code capabilities and code requirements in the code selection process, as well as thorough documentation of the code selection process.
SCOPE
1.1 This guide covers a systematic approach to the determination of the requirements for and the selection of computer codes used in a groundwater modeling project. Due to the complex nature of fluid flow and biotic and chemical transport in the subsurface, many different groundwater modeling codes exist, each having specific capabilities and limitations. Furthermore, a wide variety of situations may be encountered in projects where groundwater models are used. Determining the most appropriate code for a particular application requires a thorough analysis of the problem at hand and the required and available resources, as well as detailed description of the functionality of candidate codes.
1.2 The code selection process described in this guide consists of systematic analysis of project requirements and careful evaluation of the match between project needs and the capabilities of candidate codes. Insufficiently documented capabilities of candidate codes may require additional analysis of code functionality as part of the code selection process. Fig. 1 is provided to assist with the determination of project needs in terms of code capabilities, and, if necessary, to determine code capabilities.
1.3 This guide is one of a series of guides on groundwater modeling codes and their applications, such as Guides D5447, D5490, D5609, D5610, D5611, D5718, and D6025 .
1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide cannot replace education or experience and should be used in conjunction with professional judgement. Not all aspects of this guide may be applicable in all circumstances. This guide is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this guide be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.  
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.
FIG. 1 Checklist for Groundwater Modeling Nee...

General Information

Status
Historical
Publication Date
30-Jun-2010
ICS
13.060.10 - Water of natural resources
Technical Committee
D18 - Soil and Rock
Drafting Committee
D18.21 - Groundwater and Vadose Zone Investigations
Current Stage
Ref Project

Relations

Replaces
ASTM D6170-97(2004) - Standard Guide for Selecting a Ground-Water Modeling Code
Effective Date
01-Jul-2010
Replaced By
ASTM D6170-17 - Standard Guide for Selecting a Groundwater Modeling Code
Effective Date
01-Jan-2017

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ASTM D6170-97(2010) - Standard Guide for Selecting a Groundwater Modeling CodeASTM D6170-97(2010) - Standard Guide for Selecting a Groundwater Modeling Code
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ASTM D6170-97(2010) - Standard Guide for Selecting a Groundwater Modeling Code
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6170 − 97 (Reapproved 2010)
Standard Guide for
1
Selecting a Groundwater Modeling Code
This standard is issued under the fixed designation D6170; 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 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This guide covers a systematic approach to the determi-
responsibility of the user of this standard to establish appro-
nation of the requirements for and the selection of computer
priate safety and health practices and determine the applica-
codes used in a groundwater modeling project. Due to the
bility of regulatory limitations prior to use.
complex nature of fluid flow and biotic and chemical transport
in the subsurface, many different groundwater modeling codes
2. Referenced Documents
exist, each having specific capabilities and limitations.
2
2.1 ASTM Standards:
Furthermore, a wide variety of situations may be encountered
D653 Terminology Relating to Soil, Rock, and Contained
in projects where groundwater models are used. Determining
Fluids
the most appropriate code for a particular application requires
D5447 Guide forApplication of a Groundwater Flow Model
athoroughanalysisoftheproblemathandandtherequiredand
to a Site-Specific Problem
available resources, as well as detailed description of the
D5490 Guide for Comparing Groundwater Flow Model
functionality of candidate codes.
Simulations to Site-Specific Information
1.2 The code selection process described in this guide
D5609 Guide for Defining Boundary Conditions in Ground-
consists of systematic analysis of project requirements and
water Flow Modeling
careful evaluation of the match between project needs and the
D5610 GuideforDefiningInitialConditionsinGroundwater
capabilities of candidate codes. Insufficiently documented
Flow Modeling
capabilities of candidate codes may require additional analysis
D5611 Guide for Conducting a Sensitivity Analysis for a
of code functionality as part of the code selection process. Fig.
Groundwater Flow Model Application
1 is provided to assist with the determination of project needs
D5718 Guide for Documenting a Groundwater Flow Model
in terms of code capabilities, and, if necessary, to determine
Application
code capabilities.
D6025 Guide for Developing and Evaluating Groundwater
1.3 This guide is one of a series of guides on groundwater
Modeling Codes
modeling codes and their applications, such as Guides D5447,
D5490, D5609, D5610, D5611, D5718, and D6025.
3. Terminology
1.4 This guide offers an organized collection of information
3.1 Definitions of Terms Specific to This Standard:
or a series of options and does not recommend a specific
3.1.1 analytical model—in groundwater modeling, a model
course of action. This guide cannot replace education or
that uses closed form solutions to the governing equations
experience and should be used in conjunction with professional
applicable to groundwater flow and transport processes.
judgement. Not all aspects of this guide may be applicable in
3.1.2 code selection—the process of choosing the appropri-
all circumstances. This guide is not intended to represent or
ate computer code, algorithm, or other analysis technique
replace the standard of care by which the adequacy of a given
capable of simulating those characteristics of the physical
professional service must be judged, nor should this guide be
system required to fulfill the modeling project’s objective(s).
applied without consideration of a project’s many unique
3.1.3 computer code (computer program)—assembly of nu-
aspects. The word “Standard” in the title of this document
merical techniques, bookkeeping, and control language that
means only that the document has been approved through the
represents the model from acceptance of input data and
ASTM consensus process.
instructions to delivery of output.
1
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock
and is the direct responsibility of Subcommittee D18.21 on Groundwater and
2
Vadose Zone Investigations. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2010. Published September 2010. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2004 as D6170 – 97 (2004). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D6170-97R10. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
...

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ASTM D6452-18(2023)(Guide)
Standard Guide for Purging Methods for Wells Used for Ground Water Quality Investigations

SIGNIFICANCE AND USE
4.1 Purging is done for a variety of reasons and the purging method may depend on the hydrogeologic setting, condition of the well, or the contaminants of interest and well production rates. well hydrological conditions, condition of the well, or the contaminants of interest, and well production rates. This guide presents an approach for selecting an appropriate purging method if purging is to be performed., Water above the screened interval or open borehole may not accurately reflect ambient ground water chemistry.
Note 1: Some sampling methods, such as passive sampling, do not require the practice of purging prior to sample collection (1,2).3  
4.2 There are various methods for purging. Each purging method may have a different volume of influence within the aquifer or screened interval. Therefore, a sample collected after purging by any one method is not necessarily equivalent to samples collected after purging by the other methods. The selection of the appropriate method will be dependent on several factors, which should be defined during the development of the sampling and analysis plan. This guide describes the methods available and defines the circumstances under which each method may be appropriate.
SCOPE
1.1 This guide covers methods for purging wells used for ground water quality investigations and monitoring programs. These methods could be used for other types of programs but are not addressed in this guide.  
1.2 This guide applies only to wells sampled at the wellhead.  
1.3 This standard describes seven methods (A-G) for the selection of purging methods.
Method A—Fixed Volume Purging,
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Method C—Purging Based on Stabilization of Target Analytes,
Method D—Purging Based on Fixed Volume Combined with Indicator Parameter Stabilization,
Method E—Low Flow/Low Volume (Minimal Drawdown) Purging,
Method F—Well Evacuation Purging, and
Method G—Use of Packers in Purging.  
1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this guide means only that the document has been approved through the ASTM consensus process.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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ASTM D6517-18(2023)(Guide)
Standard Guide for Field Preservation of Ground Water Samples

SIGNIFICANCE AND USE
4.1 Ground water samples are subject to chemical, physical, and biological change relative to in- situ conditions at the ground surfaces as a result of exposure to ambient conditions during sample collection (for example, pressure, temperature, ultraviolet radiation, atmospheric oxygen, and contaminants) (1) (2).6 Physical and chemical preservation of samples minimize further changes in sample chemistry that can occur from the moment the ground water sample is retrieved, to the time it is removed from the sample container for extraction or analysis, or both. Measures also should be taken to preserve the physical integrity of the sample container.  
4.2 The need for sample preservation for specific analytes should be defined prior to the sampling event and documented in the site-specific sampling and analysis plan in accordance with Guide D5903. The decision to preserve a sample should be made on a parameter-specific basis as defined by individual analytical methods.  
4.3 This guide includes examples from government documents in the United States. When work is in other countries or regions, the local governing or regulating agencies should be consulted.  
Note 1: 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.
SCOPE
1.1 This guide covers methods for field preservation of ground water samples from the point of sampling through receipt at the laboratory. Laboratory preservation methods are not described in this guide. Purging and sampling techniques are not addressed in this standard but are addressed in Guides D6564/D6564M, D6634/D6634M, D7929, and Practice D6771.  
1.2 Ground water samples are subject to chemical, physical, and biological change relative to in situ conditions at the ground surfaces due to exposure to ambient conditions during sample collection. Physical and chemical preservation of samples minimize further changes in sample chemistry that can occur from the moment the ground water sample is retrieved, to the time it is removed from the sample container for extraction or analysis.  
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word“ Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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ASTM D6089-19(2023)(Guide)
Standard Guide for Documenting a Groundwater Sampling Event

ABSTRACT
This guide covers what and how information should be recorded in the field when sampling a ground-water monitoring well. This guide is limited to written documentation of a ground-water sampling event. When sampling ground-water monitoring wells, it is very important to thoroughly document all field activities. It is important to record procedures used and measurements immediately after they have been accomplished and are fresh in the memory. The format of the documentation is discretionary, but should be consistent from well to well and in accordance with regulatory requirements.
SIGNIFICANCE AND USE
4.1 When sampling groundwater monitoring wells, it is very important to thoroughly document all field activities. Sufficient field data should be retained to allow one to reconstruct the procedures and conditions that may have affected the integrity of a sample. The field data generated are vital to the interpretation of the chemical data obtained from laboratory analyses of samples. Field data and observations may also be useful to analytical laboratory personnel.  
4.2 Due to the changing nature of regulations and other information, users are advised to thoroughly research requirements related to packaging and shipping prior to initiating a sampling event.
Note 1: The sampling of an individual groundwater monitoring well should be repeated as closely as possible each time the monitoring well is sampled. This reduces the variability of the chemical parameters due to sampling variability which is the desired result. The intent is to detect the change in chemistry by repeating the sampling protocol at each individual well. This does not mean that all the wells are sampled the same way, nor does it prohibit changes in the sampling protocol, provided they are planned and documented.
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1.1 This guide covers what and how information should be recorded in the field when sampling a groundwater monitoring well. Following these recommendations will provide adequate documentation in most monitoring programs. In some situations, it may be necessary to record additional or different information, or both, to thoroughly document the sampling event. In other cases, it may not be necessary to record all of the information recommended in this guide. The level of documentation will be based on site-specific conditions and regulatory requirements.  
1.2 This guide is limited to written documentation of a groundwater sampling event. Other methods of documentation (that is, electronic and audiovisual) can be used but are not addressed in this guide. The specific activities addressed in this guide include documentation of static water level measurement, monitoring well purging, monitoring well sampling, field measurements, groundwater sample preparation, and groundwater sample shipment.  
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ASTM D5903-96(2023)(Guide)
Standard Guide for Planning and Preparing for a Groundwater Sampling Event

SIGNIFICANCE AND USE
3.1 The success of a sampling event is influenced by adequate planning and preparation. Use of this guide will help the groundwater sampler to methodically execute the planning and preparation.  
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ASTM D6771-21(Practice)
Standard Practice for Low-Flow Purging and Sampling Used for Groundwater Monitoring

SIGNIFICANCE AND USE
5.1 Method Considerations—The objective of most groundwater sampling programs is to obtain samples that are similar in composition to that of the formation water near the well screen. The low-flow purging and sampling method uses the stabilization of indicator parameters to determine when the pump discharge is considered to represent a flow-weighted average of the formation water. Measurements of operational parameters are used to determine potential sampling bias (for example, artifactual turbidity and increased temperature) that may have been introduced by pumping operations and to ensure that the sample is representative of formation water. The low-flow purge rate minimizes lowering of the ambient groundwater level and thereby minimizes potential entrainment of blank-riser pipe (and potentially stagnant) water above or below the screen into the screened-zone of the well. This sampling method assumes that the well has been properly designed and constructed as described in Practices D5092/D5092M and D6725/D6725M, adequately developed as described in Guide D5521/D5521M, and has received proper well maintenance and rehabilitation as described in Guide D5978/D5978M (see Note 1).
Note 1: This Standard is not intended to replace or supersede any regulatory requirements, standard operating procedure (SOP), quality assurance project plan (QAPP), ground water sampling and analysis plan (GWSAP) or site-specific regulatory permit requirements. The procedures described in this Standard may be used in conjunction with regulatory requirements, SOPs, QAPPs, GWSAPs or permits where allowed by the authority with jurisdiction.  
5.2 Applicability—Low-flow purging and sampling may be used in a monitoring well that can be pumped at a constant low-flow rate without continuously increasing drawdown in the well (2). If a well cannot be purged without continuously increasing drawdown even at very low pumping rates (for example, 50 – 100 mL/min), the well should not be sampled using th...
SCOPE
1.1 This practice describes the method of low-flow purging and sampling used to collect groundwater samples from wells to assess groundwater quality.  
1.2 The purpose of this procedure is to collect groundwater samples that represent a flow-weighted average of solute and colloid concentrations transported through the formation near the well screen under ambient conditions. Samples collected using this method can be analyzed for groundwater contaminants and/or naturally occurring analytes.  
1.3 This practice is generally not suitable for use in wells with very low-yields and cannot be conducted using grab sampling or inertial lift devices. This practice is not suitable for use in wells with non-aqueous phase liquids.  
1.4 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are approximate mathematical conversions to inch-pound units that are provided for information only and are not considered standard.  
1.5 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “standard” in the title means only that the document has been approved through the ASTM consensus process.  
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ASTM D6001/D6001M-20(Guide)
Standard Guide for Direct-Push Groundwater Sampling for Environmental Site Characterization

SIGNIFICANCE AND USE
5.1 Direct-push groundwater sampling and profiling are economical methods for obtaining discrete interval groundwater quality samples in many soils and unconsolidated formations without the expense of permanent monitoring well installation (1-10).4 Many of these devices can be used to profile groundwater quality or contamination and/or hydraulic conductivity with depth by performing repetitive sampling and testing events. DP groundwater sampling is often used in expedited site characterization (Practice D6235) and as a means to accomplish high resolution site characterization (HRSC) (11, 12). The formation to be sampled should be sufficiently permeable to allow filling of the sampler in a relatively short time. The zone to be sampled and/or slug tested can be isolated by matching sampler screen length to obtain discrete samples of thin saturated, permeable layers. Use of these sampling and hydraulic testing techniques will result in more detailed characterization of sites containing multiple aquifers. The field conditions, sampler design and data quality objectives should be reviewed to determine if development (Guide D5521/D5521M) of the screened formation is appropriate. The samplers do not have a filter pack designed to retain fines like conventional wells, but only a slotted screen or wire-mesh covered ports. So, obtaining low turbidity samples may be difficult or even impossible in formations with a significant proportion of fine-grained materials. With most systems turbidity will always be high so consult Guide D6564/D6564M if field filtration of samples is required. Discrete water sampling, combined with knowledge of location and thickness of target aquifers, may better define conditions in thin multiple aquifers than monitoring wells with long screened intervals that can intersect and allow for intercommunication of multiple aquifers (4, 6, 11-15). DP sampling performed without knowledge of the location and thickness of target aquifers can result in sampling...
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1.1 This guide covers a review of methods for sampling groundwater at discrete points or in increments by insertion of groundwater sampling devices using Direct Push Methods (D6286/D6286M, see 3.3.2). By directly pushing the sampler, the soil is displaced and helps to form an annular seal above the sampling zone. Direct-push water sampling can be one time, or multiple sampling events. Knowledge of site specific geology and hydrogeologic conditions is necessary to successfully obtain groundwater samples with these devices.  
1.2 Direct-push methods of water sampling are used for groundwater quality and geohydrologic studies. Water quality and permeability may vary at different depths below the surface depending on geohydrologic conditions. Incremental sampling or sampling at discrete depths is used to determine the distribution of contaminants and to more completely characterize geohydrologic environments. These explorations are frequently advised in characterization of hazardous and toxic waste sites and for geohydrologic studies.  
1.3 This guide covers several types of groundwater samplers; sealed screen samplers, profiling samplers, dual tube sampling systems, and simple exposed screen samplers. In general, sealed screen samplers driven to discrete depth provide the highest quality water samples. Profiling samplers using an exposed screen(s) which are purged between sampling events allow for more rapid sample collection at multiple depths. Simple exposed screen samplers driven to a test zone with no purging prior to sampling may result in more questionable water quality if exposed to upper contaminated zones, and in that case, would be considered screening devices.  
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ASTM D6029/D6029M-20(Practice)
Standard Practice for (Analytical Procedures) Determining Hydraulic Properties of a Confined Aquifer and a Leaky Confining Bed with Negligible Storage by the Hantush-Jacob Method

SIGNIFICANCE AND USE
5.1 Assumptions:  
5.1.1 The control well discharges at a constant rate, Q.  
5.1.2 The control well is of infinitesimal diameter and fully penetrates the aquifer.  
5.1.3 The aquifer is homogeneous, isotropic, and areally extensive.
Note 2: Slug and pumping tests implicitly assume a porous medium. Fractured rock and carbonate settings may not provide meaningful data and information.  
5.1.4 The aquifer remains saturated (that is, water level does not decline below the top of the aquifer).  
5.1.5 The aquifer is overlain, or underlain, everywhere by a confining bed having a uniform hydraulic conductivity and thickness. It is assumed that there is no change of water storage in this confining bed and that the hydraulic gradient across this bed changes instantaneously with a change in head in the aquifer. This confining bed is bounded on the distal side by a uniform head source where the head does not change with time.  
5.1.6 The other confining bed is impermeable.  
5.1.7 Leakage into the aquifer is vertical and proportional to the drawdown, and flow in the aquifer is strictly horizontal.  
5.1.8 Flow in the aquifer is two-dimensional and radial in the horizontal plane.  
5.2 The geometry of the well and aquifer system is shown in Fig. 1.  
5.3 Implications of Assumptions:  
5.3.1 Paragraph 5.1.1 indicates that the discharge from the control well is at a constant rate. Section 8.1 of Test Method D4050 discusses the variation from a strictly constant rate that is acceptable. A continuous trend in the change of the discharge rate could result in misinterpretation of the water-level change data unless taken into consideration.  
5.3.2 The leaky confining bed problem considered by the Hantush-Jacob solution requires that the control well has an infinitesimal diameter and has no storage. Abdul Khader and Ramadurgaiah (5) developed graphs of a solution for the drawdowns in a large-diameter control well discharging at a constant rate from an aquifer confined...
SCOPE
1.1 This practice covers an analytical procedure for determining the transmissivity and storage coefficient of a confined aquifer and the leakance value of an overlying or underlying confining bed for the case where there is negligible change of water in storage in a confining bed. This practice is used to analyze water-level or head data collected from one or more observation wells or piezometers during the pumping of water from a control well at a constant rate. With appropriate changes in sign, this practice also can be used to analyze the effects of injecting water into a control well at a constant rate.  
1.2 This analytical procedure is used in conjunction with Test Method D4050.  
1.3 Limitations—The valid use of the Hantush-Jacob method is limited to the determination of hydraulic properties for aquifers in hydrogeologic settings with reasonable correspondence to the assumptions of the Theis nonequilibrium method (Practice D4106) with the exception that in this case the aquifer is overlain, or underlain, everywhere by a confining bed having a uniform hydraulic conductivity and thickness, and in which the gain or loss of water in storage is assumed to be negligible, and that bed, in turn, is bounded on the distal side by a zone in which the head remains constant. The hydraulic conductivity of the other bed confining the aquifer is so small that it is assumed to be impermeable (see Fig. 1).
FIG. 1 Cross Section Through a Discharging Well in a Leaky Aquifer (from Reed (1)3). The Confining and Impermeable Bed Locations Can Be Interchanged  
1.4 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 nonconformance with the standard. Reporting of results in units other than SI shall not...

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ASTM D4104/D4104M-20(Practice)
Standard Practice for (Analytical Procedures) Determining Transmissivity of Nonleaky Confined Aquifers by Overdamped Well Response to Instantaneous Change in Head (Slug Tests)

SIGNIFICANCE AND USE
5.1 Assumptions of Solution of Cooper et al (1):  
5.1.1 The head change in the control well is instantaneous at time t  = 0.  
5.1.2 Well is of finite diameter and fully penetrates the aquifer.  
5.1.3 Flow in the nonleaky aquifer is radial.
Note 2: The exact conservation equation of Richards (5)with the volumetric water content can be simplified to take the form used in the solution of (1)with the storage coefficient, which implies several assumptions including that of constant total stresses (6).  
5.2 Implications of Assumptions:  
5.2.1 The mathematical equations applied ignore inertial effects and assume the water level returns the static level in an approximate exponential manner. The geometric configuration of the well and aquifer are shown in Fig. 1.
FIG. 1 Cross Section Through a Well in Which a Slug of Water is Suddenly Injected  
5.2.2 Assumptions are applicable to artesian or confined conditions and fully penetrating wells. However, this practice is commonly applied to partially penetrating wells and in unconfined aquifers where it may provide estimates of hydraulic conductivity for the aquifer interval adjacent to the open interval of the well if the horizontal hydraulic conductivity is significantly greater than the vertical hydraulic conductivity.
Note 3: Slug and pumping tests implicitly assume a porous medium. Fractured rock and carbonate settings may not provide meaningful data and information.  
5.2.3 As pointed out by Cooper et al (1) the determination of storage coefficient by this practice has questionable reliability because of the similar shape of the curves, whereas, the determination of transmissivity is not as sensitive to choosing the correct curve. However, the curve selected should not imply a storage coefficient unrealistically large or small.
Note 4: 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 us...
SCOPE
1.1 This practice covers the determination of transmissivity from the measurement of force-free (overdamped) response of a well-aquifer system to a sudden change of water level in a well. Force-free response of water level in a well to a sudden change in water level is characterized by recovery to initial water level in an approximate exponential manner with negligible inertial effects.  
1.2 The analytical procedure in this practice is used in conjunction with the field procedure in Test Method D4044/D4044M for collection of test data.  
1.3 Limitations—Slug tests are considered to provide an estimate of transmissivity. Although the assumptions of this practice prescribe a fully penetrating well (a well open through the full thickness of the aquifer), the slug test is commonly conducted using a partially penetrating well. Such a practice may be acceptable for application under conditions in which the aquifer is stratified and horizontal hydraulic conductivity is much greater than vertical hydraulic conductivity. In such a case the test would be considered to be representative of the average hydraulic conductivity of the portion of the aquifer adjacent to the open interval of the well.  
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.  
1.4.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should 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 practice to consider significant digits use...

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ASTM
ASTM D5472/D5472M-20(Practice)
Standard Practice for Determining Specific Capacity and Estimating Transmissivity at the Control Well

SIGNIFICANCE AND USE
5.1 Assumptions of the Theis (1) equation affect specific capacity and transmissivity estimated from specific capacity. These assumptions are given below:  
5.1.1 Aquifer is homogeneous and isotropic.  
5.1.2 Aquifer is horizontal, of uniform thickness, and infinite in areal extent.  
5.1.3 Aquifer is confined by impermeable strata on its upper and lower boundaries.  
5.1.4 Density gradient in the flowing fluid must be negligible and the viscous resistance to flow must obey Darcy's Law.  
5.1.5 Control well penetrates and receives water equally from the entire thickness of the aquifer.  
5.1.6 Control well has an infinitesimal diameter.  
5.1.7 Control well discharges at a constant rate.  
5.1.8 Control well operates at 100 percent efficiency.  
5.1.9 Aquifer remains saturated throughout the duration of pumping.  
5.2 Implications of Assumptions and Limitations of Method.  
5.2.1 The simplifying assumptions necessary for solution of the Theis equation and application of the method are never fully met in a field situation. The satisfactory use of the method may depend upon the application of one or more empirical correction factors being applied to the field data.  
5.2.2 Generally the values of transmissivity derived from specific capacity vary from those values determined from aquifer tests utilizing observation wells. These differences may reflect 1) that specific-capacity represents the response of a small part of the aquifer near the well and may be greatly influenced by conditions near the well such as a gravel pack or graded material resulting from well development, and 2) effects of well efficiency and partial penetration.  
5.2.3 The values of transmissivity estimated from specific capacity data are considered less accurate than values obtained from analysis of drawdowns that are observed some distance from the pumped well.
Note 1: The quality of the result produced by this practice is dependent on the competence of the personnel performing it...
SCOPE
1.1 This practice describes a procedure for conducting a specific capacity test, computing the specific capacity of a control well, and estimating the transmissivity in the vicinity of the control well. Specific capacity is the well yield per unit drawdown at an identified time after pumping started.  
1.2 This practice is used in conjunction with Test Method D4050 for conducting withdrawal and injection well tests.  
1.3 The method of determining transmissivity from specific capacity is a variation of the nonequilibrium method of Theis  (1)2 for determining transmissivity and storage coefficient of an aquifer. The Theis nonequilibrium method is given in Practice D4106.  
1.4 Limitations—The limitations of the technique for determining transmissivity are primarily related to the correspondence between the field situation and the simplifying assumptions of the Theis method.  
1.5 The scope of this practice is limited by the capabilities of the apparatus.  
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.  
1.6.1 The procedures used to specify how data are collected/recorded and calculated in this practice 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 commensurate with these considerations. It is beyond the scope of this practice to consider significant digits used in analysis methods for engineering design.  
1.7 Units—The values stated in 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...

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ASTM
ASTM D5850-20(Practice)
Standard Practice for (Analytical Procedure) Determining Transmissivity, Storage Coefficient, and Anisotropy Ratio from a Network of Partially Penetrating Wells

SIGNIFICANCE AND USE
5.1 This practice is one of several available for determining vertical anisotropy ratio. Among other available methods are Weeks ((5); see Practice D5473/D5473M), 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 need to have identical construction (screened intervals) and two or more of the observation wells need to be located at a distance from the pumped well beyond the effects of partial penetration. The procedure described in this practice general distance-drawdown method, in that it works in theory for most observation well configurations 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) should 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 may not be easily tractable by hand. Because of this, it is assumed the practitioner using this will have available a computerized procedure for evaluating the function fs. This can be accomplished u...
SCOPE
1.1 This practice 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 practice uses data from a minimum of four partially penetrating, recommended to be 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 practice.  
1.4 Units—The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are mathematical conversions, which are provided for information purposes only and are not considered standard. The reporting of results in units other than inch-pound shall not be regarded as nonconformance with this standard.  
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this standard.  
1.6 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should 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 objective; and it is common practice to increase or reduce the significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis method or engineeri...

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