ASTM D5718-95(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 2000)
Standard Guide for
Documenting a Ground-Water Flow Model Application
This standard is issued under the fixed designation D 5718; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope judgment. Not all aspects of this guide may be applicable in all
circumstances. This ASTM standard is not intended to repre-
1.1 This guide covers suggested components to be included
sent or replace the standard of care by which the adequacy of
in documenting and archival of numerical ground-water flow
a given professional service must be judged, nor should this
model applications. Model documentation includes a written
document be applied without consideration of a project’s many
and graphical presentation of model assumptions and objec-
unique aspects. The word “Standard” in the title of this
tives, the conceptual model, code description, model construc-
document means only that the document has been approved
tion, model calibration, predictive simulations, and conclu-
through the ASTM consensus process.
sions. Model archival refers to a file or set of files (in both
written and digital format) that contains logs of significant
2. Referenced Documents
model simulations (that is, calibration, sensitivity and predic-
2.1 ASTM Standards:
tion simulations), supplemental calculations, model documen-
D 653 Terminology Relating to Soil, Rock, and Contained
tation, a copy of the model source code(s) or executable file(s)
Fluids
used, or both, and input and output data sets for significant
D 5447 Guide for Application of a Ground-Water Flow
model simulations.
Model to a Site-Specific Problem
1.2 This guide presents the major steps in preparing the
D 5490 Guide for Comparing Ground-Water Flow Model
documentation and archival for a ground-water flow model
Simulations to Site-Specific Information
application. Additional information on ground-water model
D 5609 Guide for Defining Boundary Conditions in
documentation can be found in EPA-500-B-92-006.
Ground-Water Flow Modeling
1.3 This guide is specifically written for saturated, isother-
D 5610 Guide for Defining Initial Conditions in Ground-
mal, ground-water flow model applications. The elements
Water Flow Modeling
presented for documentation and archival are relevant and
D 5611 Guide for Conducting a Sensitivity Analysis for a
applicable to a wide range of modeled processes (in and out of
Ground-Water Flow Model Application
the realm of ground-water flow) and can be tailored for those
E 978 Practice for Evaluating Environmental Fate Models
applications.
of Chemicals
1.4 This guide is not intended to be all inclusive. Each
model application is unique and may require supplementary
3. Terminology
documentation and archival.
3.1 Definitions:
1.5 This standard does not purport to address all of the
3.1.1 application verification—using a set of parameter
safety concerns, if any, associated with its use. It is the
values and boundary conditions from a calibrated model to
responsibility of the user of this standard to establish appro-
approximate acceptably a second set of field data measured
priate safety and health practices and determine the applica-
under similar hydrologic conditions.
bility of regulatory limitations prior to use.
3.1.1.1 Discussion—Application verification is to be distin-
1.6 This guide offers an organized collection of information
guished from code verification, which refers to software
or a series of options and does not recommend a specific
testing, comparison to analytical solutions, and comparison
course of action. This document cannot replace education or
withothersimilarcodestodemonstratethatthecoderepresents
experience and should be used in conjunction with professional
its mathematical foundation.
3.1.2 boundary condition—a mathematical expression of a
state of the physical system which constrains the equations of
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock
the mathematical model.
and is the direct responsibility of Subcommittee D18.21 on Ground Water and
Vadose Investigations.
Current edition approved April 15, 1995. Published June 1995.
Ground-Water Modeling Compendium, USEPA, Office of Solid Waste and
Emergency Response, EPA-500-B-92-006, NTIS No. PB93207504. Available from Annual Book of ASTM Standards, Vol 04.08.
the Superintendent of Documents, U.S. Government Printing Office, Washington, Annual Book of ASTM Standards, Vol 04.09.
DC, 20402. Annual Book of ASTM Standards, Vol 11.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5718–95 (2000)
3.1.3 calibration (model application)—the process of refin- geology, hydrology, and land use. Present a regional map with
ing the model representation of the hydrogeologic framework, the study area defined.
hydraulic properties, and boundary conditions to achieve a
5.3 Conceptual Model—Present the conceptual model as a
desired degree of correspondence between the model simula- site-specific interpretation (based on collected data) of the
tion and observations of the ground-water flow system.
characteristics and dynamics of the physical system being
3.1.4 calibration targets—measured, observed calculated or studied. Include discussion on the aquifer system (both geo-
estimated hydraulic head or ground-water flow rates which the
logic and hydrologic aspects), hydrologic boundaries, hydrau-
model must reproduce, at least approximately, to be considered lic properties, sources and sinks, and a water budget. The level
calibrated.
of detail in this interpretation should be consistent with the
3.1.5 conceptual model—an interpretation or working de- available data. Present and discuss data set origins, strengths,
scription of the characteristics and dynamics of the physical
deficiencies and their effects on the conceptual model.
system.
5.3.1 Aquifer System—Present an interpretation of the geo-
3.1.6 computer code (computer program)—the assembly of
logic and hydrologic characteristics of the aquifer system.
numerical techniques, bookkeeping, and control language that
Where appropriate, present hydrogeologic cross-sections and
represents the model from acceptance of input data and
structural contour and potentiometric surface maps to illustrate
instructions to delivery of output.
data and interpretations.
3.1.7 ground-water flow model—application of a math-
5.3.2 Hydrologic Boundaries—Discuss the hydrologic
ematical model to represent a site-specific ground-water flow
boundaries that exist and their type(s) for the aquifer system.
system.
5.3.3 Hydraulic Properties—Presentknownhydraulicprop-
3.1.8 mathematical model—( a) mathematical equations
erties of the aquifer system, such as hydraulic conductivity,
expressing the physical system and including simplifying
transmissivity, storativity, and porosity. If these parameters
assumptions; (b) the representation of a physical system by
vary spatially, present the interpretation in map form.
mathematical expressions from which the behavior of the
5.3.4 Sources and Sinks—Present details on the location (if
system can be deduced with known accuracy.
a point source or sink), and the relative magnitude of the
3.1.9 simulation log—a log used to document (in terms of
source(s) or sink(s). If the source or sink is areal in extent,
input data, code used, simulation purpose and results) of
present information as to the variability or distribution.
individual model simulations. (See Appendix X1.)
5.3.5 Water Budget—Present a water budget (either quali-
3.2 For definitions of other terms used in this guide, see
tative or quantitative, depending on the study objectives) that
Terminology D 653.
interprets how water is entering the aquifer system, how it
moves through the aquifer system, and how it exits the aquifer
4. Significance and Use
system.
4.1 Ground-water flow models are tools frequently applied
5.4 Computer Code Description—Present a description of
for the analysis of hydrogeologic systems. Due to the signifi-
the code used and discuss the selection criteria for the code. If
cance of many decisions based upon modeling results, quality
a custom or altered code is used, list the vendor name, any
assurance measures need to be applied to model applications.
enhancements to the code, and how the code was tested.
Complete model documentation is a mechanism to ensure the
Present the simplifying assumptions inherent to the code, the
quality of the effort.
limitations to the code, and the governing equations that the
4.2 Several federal and state agencies have developed poli-
c
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