ASTM D5718-95(2012)
(Guide)Standard Guide for Documenting a Groundwater Flow Model Application
Standard Guide for Documenting a Groundwater Flow Model Application
SIGNIFICANCE AND USE
4.1 Groundwater flow models are tools frequently applied for the analysis of hydrogeologic systems. Due to the significance of many decisions based upon modeling results, quality assurance measures need to be applied to model applications. Complete model documentation is a mechanism to ensure the quality of the effort.
4.2 Several federal and state agencies have developed policies regarding model documentation. This guide provides consistency amongst current policies, and should be used as a framework for model documentation.
SCOPE
1.1 This guide covers suggested components to be included in documenting and archival of numerical groundwater flow model applications. Model documentation includes a written and graphical presentation of model assumptions and objectives, the conceptual model, code description, model construction, model calibration, predictive simulations, and conclusions. Model archival refers to a file or set of files (in both written and digital format) that contains logs of significant model simulations (that is, calibration, sensitivity and prediction simulations), supplemental calculations, model documentation, a copy of the model source code(s) or executable file(s) used, or both, and input and output data sets for significant model simulations.
1.2 This guide presents the major steps in preparing the documentation and archival for a groundwater flow model application. Additional information on groundwater model documentation can be found in EPA-500-B-92-006.2
1.3 This guide is specifically written for saturated, isothermal, groundwater flow model applications. The elements presented for documentation and archival are relevant and applicable to a wide range of modeled processes (in and out of the realm of groundwater flow) and can be tailored for those applications.
1.4 This guide is not intended to be all inclusive. Each model application is unique and may require supplementary documentation and archival.
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.
1.6 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.
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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: D5718 − 95(Reapproved 2012)
Standard Guide for
Documenting a Groundwater Flow Model Application
This standard is issued under the fixed designation D5718; 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 1.6 This guide offers an organized collection of information
or a series of options and does not recommend a specific
1.1 This guide covers suggested components to be included
course of action. This document cannot replace education or
in documenting and archival of numerical groundwater flow
experienceandshouldbeusedinconjunctionwithprofessional
model applications. Model documentation includes a written
judgment. Not all aspects of this guide may be applicable in all
and graphical presentation of model assumptions and
circumstances. This ASTM standard is not intended to repre-
objectives, the conceptual model, code description, model
sent or replace the standard of care by which the adequacy of
construction, model calibration, predictive simulations, and
a given professional service must be judged, nor should this
conclusions. Model archival refers to a file or set of files (in
document be applied without consideration of a project’s many
bothwrittenanddigitalformat)thatcontainslogsofsignificant
unique aspects. The word “Standard” in the title of this
model simulations (that is, calibration, sensitivity and predic-
document means only that the document has been approved
tion simulations), supplemental calculations, model
through the ASTM consensus process.
documentation, a copy of the model source code(s) or execut-
able file(s) used, or both, and input and output data sets for
2. Referenced Documents
significant model simulations.
2.1 ASTM Standards:
1.2 This guide presents the major steps in preparing the
D653 Terminology Relating to Soil, Rock, and Contained
documentation and archival for a groundwater flow model
Fluids
application. Additional information on groundwater model
D5447 Guide forApplication of a Groundwater Flow Model
documentation can be found in EPA-500-B-92-006.
to a Site-Specific Problem
D5490 Guide for Comparing Ground-Water Flow Model
1.3 This guide is specifically written for saturated,
Simulations to Site-Specific Information
isothermal, groundwater flow model applications. The ele-
D5609 Guide for Defining Boundary Conditions in Ground-
ments presented for documentation and archival are relevant
water Flow Modeling
and applicable to a wide range of modeled processes (in and
D5610 GuideforDefiningInitialConditionsinGroundwater
out of the realm of groundwater flow) and can be tailored for
Flow Modeling
those applications.
D5611 Guide for Conducting a Sensitivity Analysis for a
1.4 This guide is not intended to be all inclusive. Each
Ground-Water Flow Model Application
model application is unique and may require supplementary
E978 Practice for Evaluating Mathematical Models for the
documentation and archival.
Environmental Fate of Chemicals (Withdrawn 2002)
1.5 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety and health practices and determine the applica-
3.1.1 application verification—using a set of parameter
bility of regulatory limitations prior to use.
values and boundary conditions from a calibrated model to
approximate acceptably a second set of field data measured
under similar hydrologic conditions.
1 3.1.1.1 Discussion—Application verification is to be distin-
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
guished from code verification, which refers to software
Vadose Zone Investigations.
Current edition approved May 1, 2012. Published December 2012. Originally
approved in 1995. Last previous edition approved in 2006 as D5718 – 95 (2006). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/D5718-95R12. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Ground-Water Modeling Compendium, USEPA, Office of Solid Waste and Standards volume information, refer to the standard’s Document Summary page on
Emergency Response, EPA-500-B-92-006, NTIS No. PB93207504. Available from the ASTM website.
the Superintendent of Documents, U.S. Government Printing Office, Washington, The last approved version of this historical standard is referenced on
DC, 20402. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5718 − 95 (2012)
testing, comparison to analytical solutions, and comparison model area. Identify the individuals involved with the model-
withothersimilarcodestodemonstratethatthecoderepresents ing effort and their roles.
its mathematical foundation.
5.2.1 Modeling Objectives—Clearly state the modeling
objectives, the purpose and goals of the study, and the
3.1.2 boundary condition—a mathematical expression of a
applicability of the model as part of the study. Discuss what
state of the physical system which constrains the equations of
types of predictions are to be made with the model.
the mathematical model.
5.2.2 Model Function—Describe how the model was used
3.1.3 calibration (model application)—the process of refin-
to satisfy the purpose and goals of the study.
ing the model representation of the hydrogeologic framework,
5.2.3 General Setting—Include a general setting of relevant
hydraulic properties, and boundary conditions to achieve a
information on the regional characteristics of topography,
desired degree of correspondence between the model simula-
geology, hydrology, and land use. Present a regional map with
tion and observations of the groundwater flow system.
the study area defined.
3.1.4 calibration targets—measured, observed calculated or
estimated hydraulic head or groundwater flow rates which the
5.3 Conceptual Model—Present the conceptual model as a
model must reproduce, at least approximately, to be considered site-specific interpretation (based on collected data) of the
calibrated.
characteristics and dynamics of the physical system being
studied. Include discussion on the aquifer system (both geo-
3.1.5 conceptual model—an interpretation or working de-
logic and hydrologic aspects), hydrologic boundaries, hydrau-
scription of the characteristics and dynamics of the physical
lic properties, sources and sinks, and a water budget. The level
system.
of detail in this interpretation should be consistent with the
3.1.6 computer code (computer program)—the assembly of
available data. Present and discuss data set origins, strengths,
numerical techniques, bookkeeping, and control language that
deficiencies and their effects on the conceptual model.
represents the model from acceptance of input data and
5.3.1 Aquifer System—Present an interpretation of the geo-
instructions to delivery of output.
logic and hydrologic characteristics of the aquifer system.
3.1.7 groundwater flow model—application of a mathemati-
Where appropriate, present hydrogeologic cross-sections and
cal model to represent a site-specific groundwater flow system.
structural contour and potentiometric surface maps to illustrate
data and interpretations.
3.1.8 mathematical model—( a) mathematical equations
expressing the physical system and including simplifying 5.3.2 Hydrologic Boundaries—Discuss the hydrologic
assumptions; (b) the representation of a physical system by boundaries that exist and their type(s) for the aquifer system.
mathematical expressions from which the behavior of the
5.3.3 Hydraulic Properties—Present known hydraulic prop-
system can be deduced with known accuracy.
erties of the aquifer system, such as hydraulic conductivity,
transmissivity, storativity, and porosity. If these parameters
3.1.9 simulation log—a log used to document (in terms of
vary spatially, present the interpretation in map form.
input data, code used, simulation purpose and results) of
individual model simulations. (See Appendix X1.)
5.3.4 Sources and Sinks—Present details on the location (if
a point source or sink), and the relative magnitude of the
3.2 For definitions of other terms used in this guide, see
source(s) or sink(s). If the source or sink is areal in extent,
Terminology D653.
present information as to the variability or distribution.
5.3.5 Water Budget—Present a water budget (either qualita-
4. Significance and Use
tive or quantitative, depending on the study objectives) that
4.1 Groundwater flow models are tools frequently applied
interprets how water is entering the aquifer system, how it
for the analysis of hydrogeologic systems. Due to the signifi-
moves through the aquifer system, and how it exits the aquifer
cance
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