ASTM D5980-16(2024)

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.
Designation: D5980 − 16 (Reapproved 2024)
Standard Guide for
Selection and Documentation of Existing Wells for Use in
Environmental Site Characterization and Monitoring
This standard is issued under the fixed designation D5980; 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 aspects. The word “Standard” in the title of this document
means only that the document has been approved through the
1.1 This guide covers the use of existing wells for environ-
ASTM consensus process.
mental site characterization and monitoring. It covers the
1.8 This international standard was developed in accor-
following major topics: criteria for determining the suitability
dance with internationally recognized principles on standard-
of existing wells for hydrogeologic characterization and
ization established in the Decision on Principles for the
groundwater quality monitoring, types of data needed to
Development of International Standards, Guides and Recom-
document the suitability of an existing well, and the relative
mendations issued by the World Trade Organization Technical
advantages and disadvantages of existing large- and small-
Barriers to Trade (TBT) Committee.
capacity wells.
1.2 This guide should be used in conjunction with Guide
2. Referenced Documents
D5730, that provides a general approach for environmental site
2.1 Pertinent guides addressing specific information neces-
investigations.
sary to utilize existing wells for hydrologic and water-quality
1.3 This guide does not specifically address design and
data for environmental site characterization. A comprehensive
construction of new monitoring or supply wells. Refer to
list of guides, standards, methods, practices, and terminology is
Practices D5092/D5092M and D5787.
contained in Guide D5730. Other guidance documents cover-
1.4 This guide does not specifically address groundwater
ing procedures for environmental site investigations with
sampling procedures. Refer to Guide D5903.
specific objectives or in particular geographic settings may be
available from federal, state, and other agencies or organiza-
1.5 The values stated in SI units are to be regarded as
tions. The appropriate agency or organization should be
standard. No other units of measurement are included in this
contacted to determine the availability and most current edition
standard.
of such documents.
1.6 This standard does not purport to address all of the
2.2 ASTM Standards:
safety concerns, if any, associated with its use. It is the
D653 Terminology Relating to Soil, Rock, and Contained
responsibility of the user of this standard to establish appro-
Fluids
priate safety, health, and environmental practices and deter-
D5092/D5092M Practice for Design and Installation of
mine the applicability of regulatory limitations prior to use.
Groundwater Monitoring Wells
1.7 This guide offers an organized collection of information
D5254/D5254M Practice for Minimum Set of Data Ele-
or a series of options and does not recommend a specific
ments to Identify a Groundwater Site (Withdrawn 2019)
course of action. This guide cannot replace education or
D5408 Guide for Set of Data Elements to Describe a
experience and should be used in conjunction with professional
Groundwater Site; Part One—Additional Identification
judgment. Not all aspects of this guide may be applicable in all
Descriptors (Withdrawn 2019)
circumstances. This guide is not intended to represent or
D5409/D5409M Guide for Set of Data Elements to Describe
replace the standard of care by which the adequacy of a given
a Groundwater Site;Part Two—Physical Descriptors
professional service must be judged, nor should this guide be
(Withdrawn 2019)
applied without consideration of a project’s many unique
1 2
This guide is under the jurisdiction of ASTM Committee D18 on Soil and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Rockand is the direct responsibility of Subcommittee D18.21 on Groundwater and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Vadose Zone Investigations. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2024. Published January 2024. Originally the ASTM website.
approved in 1996. Last previous edition approved in 2016 as D5980–16. DOI: The last approved version of this historical standard is referenced on
10.1520/D5980-16R24. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5980 − 16 (2024)
D5410 Guide for Set of Data Elements to Describe a 5. General Considerations in Selection and Use of
Groundwater Site;Part Three—Usage Descriptors (With- Existing Wells
drawn 2016)
5.1 Selection and use of existing wells should take place in
D5521/D5521M Guide for Development of Groundwater
the context of a conceptual framework consisting of a descrip-
Monitoring Wells in Granular Aquifers
tion of the system, including, as necessary, physical and
D5730 Guide for Site Characterization for Environmental
cultural characteristics, such as climate, hydrology, ecology,
Purposes With Emphasis on Soil, Rock, the Vadose Zone
physiography, population, water use and land use, and hypoth-
and Groundwater (Withdrawn 2013)
eses about processes of interest that occur within that system.
D5753 Guide for Planning and Conducting Geotechnical
A step-wise approach for conceptualization and characteriza-
Borehole Geophysical Logging
tion is a direct approach to develop the framework for
D5787 Practice for Monitoring Well Protection At or Near 4
Hydrologic Systems as described in Kolm (1) , (see Guide
Land Surface
D5979). Conceptualization of hydrologic and regional ground-
D5903 Guide for Planning and Preparing for a Groundwater
water quality systems can be formulated using the methods
Sampling Event
outlined in Alley (2). The framework is reviewed and refined
D5979 Guide for Conceptualization and Characterization of
by an iterative process of data collection and analysis, testing
Groundwater Systems
hypotheses with data collected, and identifying data needs to
further revise the framework. Refinement must be made within
3. Terminology
the limits established by the accuracy, precision, and complete-
ness of the data. Methods for data collection are selected that
3.1 Definitions—For common definitions of technical terms
will provide data appropriate for testing hypotheses which
used in this standard, refer to Terminology D653.
evaluate the conceptual framework.
3.2 Definitions of Terms Specific to This Standard:
5.2 Well design and installation can greatly affect the quality
3.2.1 supply (production) well, n—well primarily installed
of groundwater monitoring. Such effects apply both to existing
for public supply, irrigation, and industrial use. Supply wells
wells and to wells specifically installed for a purpose. The
may be used as an observation well.
effects of well design and installation, therefore, need to be
considered regardless of whether existing wells are selected or
4. Significance and Use
if wells are specifically installed for a specific purpose. The
4.1 This guide describes a general approach for the use of
most common feature of an existing well that may render it
existing wells in environmental investigations with a primary
unsuitable for water level measurement or water-quality moni-
focus on the subsurface and major factors affecting the surface
toring is that the well is completed in multiple hydrogeologic
and subsurface environment.
units causing water levels and water-quality parameters to
reflect a mixing of multiple hydrogeologic units. Such data
4.2 Existing wells represent a valuable source of informa-
cannot be reliably compared with data from wells completed in
tion for subsurface environmental investigations. Specific uses
the individual hydrogeologic units.
of existing wells include:
4.2.1 Well driller logs provide information on subsurface 5.3 Major steps in the selection of existing wells for
lithology and major water-bearing units in an area. Existing
environmental investigations include: developing specific cri-
wells can also offer access for downhole geophysical logging teria for evaluating the suitability of existing wells in relation
for stratigraphic and aquifer interpretations. Examples include
to the objectives of the investigations (see Section 6), conduct-
natural gamma logs in cased wells and an entire suite of ing an inventory of existing wells in the area of interest (see
methods in uncased bedrock wells (see Guide D5753). This
8.1), documenting the characteristics of the wells identified in
information can assist in developing the preliminary concep- the inventory that are relevant to the selection criteria (see 8.2),
tual model of the site.
and identification of wells that satisfy the selection criteria (see
Section 9).
4.2.2 Well tests using existing wells may provide informa-
tion on the hydrologic characteristics of an aquifer.
6. Well-Selection Criteria
4.2.3 Monitoring of water levels in existing wells, provided
that they are cased in the aquifer of interest, allow development 6.1 Assessing the suitability of existing wells for hydrologi-
cal and groundwater quality studies requires development of
of potentiometric maps and interpretations of groundwater flow
directions and gradients. specific well-selection criteria. The criteria are based on
considerations of project objectives by defining the problem to
4.2.4 Existing wells are the primary means by which re-
be solved, the conceptual framework, and data-collection
gional drinking water quality is evaluated and monitored.
requirements.
4.2.5 Existing wells may assist in the mapping of contami-
nant plumes, and in ongoing monitoring of groundwater
6.2 Specific Well-Selection Criteria—Specific criteria will
quality changes at the site-specific level.
depend on the objectives of the investigation. The following
general criteria will apply to most situations:
4.3 Data from existing wells should only be used when
characteristics of the well have been sufficiently documented to
determine that they satisfy criteria for the purpose for which
The boldface numbers in parentheses refer to the list of references at the end of
the data are to be used. this standard.
D5980 − 16 (2024)
6.2.1 The well is suitably located for use in relation to the wells specially designed and installed to monitor hydrologic or
conceptual framework. water-quality studies, or both (see 7.4). Each type of well has
its own general advantages and disadvantages.
6.2.2 The well must be completed in the targeted hydrogeo-
logic unit or units.
7.2 Large-Capacity Supply Wells—Large-capacity supply
6.2.3 Well design and construction must not bias water level
wells are usually developed for drinking water systems that
measurements or water-quality sampling results (see Note 1).
supply multiple households, and for irrigation and industrial
Section 7 provides information on the general characteristics of
purposes.
major types of existing wells.
7.2.1 Advantages:
NOTE 1—Gillham et al. (3), provides information on the suitability of
7.2.1.1 Documentation of well construction commonly is
materials coming in contact with water samples and that table provides
good.
information on the compatibility of well casing materials with different
organic contaminants. 7.2.1.2 Large-capacity wells generally are well developed
and fully purged.
6.2.4 The well is accessible for measurements and sam-
7.2.1.3 Long-term access may be possible, particularly for
pling.
municipal wells.
6.2.5 The well’s maintenance condition may not compro-
7.2.1.4 Large-capacity wells generally provide a larger ver-
mise it as a sampling point; however, there are examples that
may compromise it as a sampling point, that is, a cracked tical mix of water in an aquifer or aquifer system than
small-capacity wells, and thus can provide a more integrated
casing allowing non-screened water into the well.
measure of regional groundwater quality than small-capacity
6.3 Examples of Well Selection Criteria—The following are
wells.
illustrative examples of criteria for specific investigation ob-
7.2.1.5 Much of the water produced for irrigation and
jectives (see Note 2).
municipal water is from large-capacity wells equipped with
NOTE 2—These are illustrative examples and should not be construed as
taps which allow a direct sample of the pumped water.
recommended criteria.
7.2.1.6 Long-term water-quality and quantity data may be
6.3.1 A project to determine the quality of potable ground-
available.
water might require the following selection criteria: wells
7.2.2 Disadvantages:
selected must be used for public water supply, must be
7.2.2.1 Large-capacity wells may not have flow-rate con-
geographically distributed over the entire aquifer of interest,
trols and a sampling point near the well head.
and must be able to be sampled prior to any water treatment.
7.2.2.2 High pumping rates may entrain artifacts, such as
6.3.2 All wells or a subset of wells down-gradient from a
colloids or suspended material, into the sample stream.
hazardous-waste site would be unsuitable to include in a
7.2.2.3 Pumping schedules could be irregular: for example,
network designed for a study to determine non-point source
irrigation wells generally are pumped seasonally, and could
groundwater quality.
lead to seasonal variations in water quality that actually are an
6.3.3 Choosing a well located down-gradient of a complex
artifact of the pumping regime.
mix of land uses would be inappropriate in a study designed to
7.2.2.4 Large capacity wells may have a long vertical gravel
assess the effects of specific land uses on groundwater quality.
pack, screened or open intervals might span more than one
6.3.4 A supply well screened over a long interval would not
aquifer or aquifer system, making them unsuitable for poten-
be appropriate for investigating small-scale vertical variations
tiometric mapping or water quality monitoring. For example,
in water quality down-gradient of a land
...