iTeh StandardsiTeh Standards
EURUSD
Your shopping cart is empty.
ASTM

ASTM D5611-94(2002)

(Guide)

Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model Application

Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model Application

SIGNIFICANCE AND USE
After a model has been calibrated and used to draw conclusions about a physical hydrogeologic system (for example, estimating the capture zone of a proposed extraction well), a sensitivity analysis can be performed to identify which model inputs have the most impact on the degree of calibration and on the conclusions of the modeling analysis.
If variations in some model inputs result in insignificant changes in the degree of calibration but cause significantly different conclusions, then the mere fact of having used a calibrated model does not mean that the conclusions of the modeling study are valid.
This guide is not meant to be an inflexible description of techniques of performing a sensitivity analysis; other techniques may be applied as appropriate and, after due consideration, some of the techniques herein may be omitted, altered, or enhanced.
SCOPE
1.1 This guide covers techniques that should be used to conduct a sensitivity analysis for a ground-water flow model. The sensitivity analysis results in quantitative relationships between model results and the input hydraulic properties or boundary conditions of the aquifers.
1.2 After a ground-water flow model has been calibrated, a sensitivity analysis may be performed. Examination of the sensitivity of calibration residuals and model conclusions to model inputs is a method for assessing the adequacy of the model with respect to its intended function.
1.3 After a model has been calibrated, a modeler may vary the value of some aspect of the conditions applying solely to the prediction simulations in order to satisfy some design criteria. For example, the number and locations of proposed pumping wells may be varied in order to minimize the required discharge. Insofar as these aspects are controllable, variation of these parameters is part of an optimization procedure, and, for the purposes of this guide, would not be considered to be a sensitivity analysis. On the other hand, estimates of future conditions that are not controllable, such as the recharge during a postulated drought of unknown duration and severity, would be considered as candidates for a sensitivity analysis.
1.4 This guide presents the simplest acceptable techniques for conducting a sensitivity analysis. Other techniques have been developed by researchers and could be used in lieu of the techniques in this guide.
1.5 This guide is written for performing sensitivity analyses for ground-water flow models. However, these techniques could be applied to other types of ground-water related models, such as analytical models, multi-phase flow models, non-continuum (karst or fracture flow) models, or mass transport models.
1.6 This guide is one of a series on ground-water modeling codes (software) and their applications, such as Guide D5447 and Guide D5490. Other standards have been prepared on environmental modeling, such as Practice E978.
1.7 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.8 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.  
1.9 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 judgement. Not all aspects of this guide may be applicalbe 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 unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process.

General Information

Status
Historical
Publication Date
14-Sep-1994
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 D5611-94e1 - Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model Application
Effective Date
15-Sep-1994
Replaced By
ASTM D5611-94(2008) - Standard Guide for Conducting a Sensitivity Analysis for a Groundwater Flow Model Application
Effective Date
15-Sep-2008
Referred By
ASTM D5981/D5981M-18 - Standard Guide for Calibrating a Groundwater Flow Model Application
Effective Date
15-Sep-1994
Referred By
ASTM D6170-17 - Standard Guide for Selecting a Groundwater Modeling Code
Effective Date
15-Sep-1994
Referred By
ASTM D6033-16 - Standard Guide for Describing the Functionality of a Groundwater Modeling Code
Effective Date
15-Sep-1994
Referred By
ASTM D5447-17 - Standard Guide for Application of a Numerical Groundwater Flow Model to a Site-Specific Problem
Effective Date
15-Sep-1994
Referred By
ASTM E2081-22 - Standard Guide for Risk-Based Corrective Action
Effective Date
15-Sep-1994

Buy Standard

ASTM D5611-94(2002) - Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model ApplicationASTM D5611-94(2002) - Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model Application
PreviousNext
Guide
ASTM D5611-94(2002) - Standard Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model Application
English language
5 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)

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:D5611–94 (Reapproved 2002)
Standard Guide for
Conducting a Sensitivity Analysis for a Ground-Water Flow
1
Model Application
This standard is issued under the fixed designation D5611; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 The values stated in inch-pound units are to be regarded
as the standard. The SI units given in parentheses are for
1.1 This guide covers techniques that should be used to
information only.
conduct a sensitivity analysis for a ground-water flow model.
1.8 This standard does not purport to address all of the
The sensitivity analysis results in quantitative relationships
safety concerns, if any, associated with its use. It is the
between model results and the input hydraulic properties or
responsibility of the user of this standard to establish appro-
boundary conditions of the aquifers.
priate safety and health practices and determine the applica-
1.2 After a ground-water flow model has been calibrated, a
bility of regulatory limitations prior to use.
sensitivity analysis may be performed. Examination of the
1.9 This guide offers an organized collection of information
sensitivity of calibration residuals and model conclusions to
or a series of options and does not recommend a specific
model inputs is a method for assessing the adequacy of the
course of action. This document cannot replace education or
model with respect to its intended function.
experience and should be used in conjunction with professional
1.3 After a model has been calibrated, a modeler may vary
judgment. Not all aspects of this guide may be applicable in all
the value of some aspect of the conditions applying solely to
circumstances. This ASTM standard is not intended to repre-
the prediction simulations in order to satisfy some design
sent or replace the standard of care by which the adequacy of
criteria. For example, the number and locations of proposed
a given professional service must be judged, nor should this
pumpingwellsmaybevariedinordertominimizetherequired
document be applied without consideration of a project’s many
discharge.Insofarastheseaspectsarecontrollable,variationof
unique aspects. The word “Standard” in the title of this
these parameters is part of an optimization procedure, and, for
document means only that the document has been approved
the purposes of this guide, would not be considered to be a
through the ASTM consensus process.
sensitivity analysis. On the other hand, estimates of future
conditionsthatarenotcontrollable,suchastherechargeduring
2. Referenced Documents
a postulated drought of unknown duration and severity, would
2.1 ASTM Standards:
be considered as candidates for a sensitivity analysis.
D653 Terminology Relating to Soil, Rock, and Contained
1.4 This guide presents the simplest acceptable techniques
2
Fluids
for conducting a sensitivity analysis. Other techniques have
D5447 Guide for Application of a Ground-Water Flow
been developed by researchers and could be used in lieu of the
2
Model to a Site-Specific Problem
techniques in this guide.
D5490 Guide for Comparing Ground-Water Flow Model
1.5 This guide is written for performing sensitivity analyses
2
Simulations to Site-Specific Information
for ground-water flow models. However, these techniques
E978 Practice for Evaluating Mathematical Models for the
couldbeappliedtoothertypesofground-waterrelatedmodels,
3
Environmental Fate of Chemicals
such as analytical models, multi-phase flow models, non-
continuum (karst or fracture flow) models, or mass transport
3. Terminology
models.
3.1 Definitions:
1.6 This guide is one of a series on ground-water modeling
3.1.1 boundary condition—a mathematical expression of a
codes (software) and their applications, such as Guide D5447
stateofthephysicalsystemthatconstrainstheequationsofthe
and Guide D5490. Other standards have been prepared on
mathematical model.
environmental modeling, such as Practice E978.
1
This guide is under the jurisdiction of ASTM Committee D18 on Soil and
Rockand is the direct responsibility of Subcommittee D18.21 on GroundWater and
2
Vadose Zone Investigations. Annual Book of ASTM Standards, Vol 04.08.
3
Current edition approved Sept. 15, 1994. Published October 1994. Annual Book of ASTM Standards, Vol 11.05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
D5611–94 (2002)
3.1.2 calibration—the process of refining the model repre- ample, estimating the capture zone of a proposed extraction
sentation of the hydrogeologi
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.

This May Also Interest You

ASTM
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,
Method B—Purging Based on Stabilization of Indicator Parameters,
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.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Guide
    6 pages
    English language
    sale 15% off
ASTM
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.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical ...

  • Guide
    6 pages
    English language
    sale 15% off
ASTM
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.
Note 2: The quality of the results produced by this standard is dependent on the competence of 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 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.  
1.3 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.  
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 appli...

  • Guide
    3 pages
    English language
    sale 15% off
ASTM
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.  
3.2 This guide should be used by a professional or technician that has training or experience in groundwater sampling.
SCOPE
1.1 This guide covers planning and preparing for a groundwater sampling event. It includes technical and administrative considerations and procedures. Example checklists are also provided as Appendices.  
1.2 This guide may not cover every consideration procedure, or both, that is necessary before all groundwater sampling projects. In karst or fractured rock terranes, it may be appropriate to collect groundwater samples from springs (see Guide D5717). This guide focuses on sampling of groundwater from monitoring wells; however, most of the guidance herein can apply to the sampling of springs as well.  
1.3 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.  
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 international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Guide
    5 pages
    English language
    sale 15% off
ASTM
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.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standar...

  • Standard
    8 pages
    English language
    sale 15% off
  • Standard
    8 pages
    English language
    sale 15% off
ASTM
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...
SCOPE
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.  
1.4 Methods for obtaining groundwater samples for water quality analysis and detection of contaminants are presented. These methods include use of related standards such as; selection of purging and sampling devices (Guide D6452 and D6634/D6634M), samp...

  • Guide
    22 pages
    English language
    sale 15% off
  • Guide
    22 pages
    English language
    sale 15% off
ASTM
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...

  • Standard
    11 pages
    English language
    sale 15% off
  • Standard
    11 pages
    English language
    sale 15% off
ASTM
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...

  • Standard
    5 pages
    English language
    sale 15% off
  • Standard
    5 pages
    English language
    sale 15% off
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...

  • Standard
    6 pages
    English language
    sale 15% off
  • Standard
    6 pages
    English language
    sale 15% off
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...

  • Standard
    13 pages
    English language
    sale 15% off
  • Standard
    13 pages
    English language
    sale 15% off