ASTM D6033-96(2008)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D6033 − 96(Reapproved 2008)
Standard Guide for
Describing the Functionality of a Groundwater Modeling
Code
This standard is issued under the fixed designation D6033; 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 1.4 Although groundwater modeling codes exist for simu-
lation of many different groundwater systems, one may en-
1.1 This guide presents a systematic approach to the classi-
counter situations in which no existing code is applicable. In
ficationanddescriptionofcomputercodesusedingroundwater
those cases, the systematic description of modeling needs may
modeling. Due to the complex nature of fluid flow and biotic
be based on the methodology presented in this guide.
and chemical transport in the subsurface, many different types
of groundwater modeling codes exist, each having specific 1.5 This guide is one of a series of guides on groundwater
capabilities and limitations. Determining the most appropriate modeling codes and their applications, such as Guides D5447,
codeforaparticularapplicationrequiresathoroughanalysisof D5490, D5609, D5610, D5611, and D5718.
the problem at hand and the required and available resources,
1.6 Complete adherence to this guide may not be feasible.
as well as a detailed description of the functionality of
For example, research developments may result in new types
potentially applicable codes.
of codes not yet described in this guide. In any case, code
1.2 Typically, groundwater modeling codes are nonparam- documentation should contain a section containing a complete
eterized mathematical descriptions of the causal relationships description of a code’s functions, features, and capabilities.
among selected components of the aqueous subsurface and the
1.7 This guide offers an organized collection of information
chemical and biological processes taking place in these sys-
or a series of options and does not recommend a specific
tems. Many of these codes focus on the presence and move-
course of action. This document cannot replace education or
ment of water, dissolved chemical species and biota, either
experience and should be used in conjunction with professional
under fully or partially saturated conditions, or a combination
judgment. Not all aspects of this guide may be applicable in all
of these conditions. Other codes handle the joint movement of
circumstances. This ASTM standard is not intended to repre-
water and other fluids, either as a gas or a nonaqueous phase
sent or replace the standard of care by which the adequacy of
liquid, or both, and the complex phase transfers that might take
a given professional service must be judged, nor should this
place between them. Some codes handle interactions between
document be applied without consideration of a project’s many
the aqueous subsurface (for example, a groundwater system)
unique aspects. The word “Standard” in the title of this
and other components of the hydrologic system or with
document means only that the document has been approved
nonaqueous components of the environment.
through the ASTM consensus process.
1.3 The classification protocol is based on an analysis of the
major function groups present in groundwater modeling codes. 2. Referenced Documents
Additional code functions and features may be identified in
2.1 ASTM Standards:
determiningthefunctionalityofacode.Acompletedescription
D653 Terminology Relating to Soil, Rock, and Contained
of a code’s functionality contains the details necessary to
Fluids
understand the capabilities and potential use of a groundwater
D5447 Guide for Application of a Ground-Water Flow
modeling code. Tables are provided with explanations and
Model to a Site-Specific Problem
examplesoffunctionsandfunctiongroupsforselectedtypesof
D5490 Guide for Comparing Ground-Water Flow Model
codes. Consistent use of the descriptions provided in the
Simulations to Site-Specific Information
classification protocol and elaborate functionality analysis
D5609 Guide for Defining Boundary Conditions in Ground-
form the basis for efficient code selection.
Water Flow Modeling
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
Vadose Zone Investigations. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 15, 2008. Published November 2008. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1996. Last previous edition approved in 2002 as D6033 – 96 (2002) Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D6033-96R08. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6033 − 96 (2008)
D5610 Guide for Defining Initial Conditions in Ground- 3.2.9 inverse model, n—an application of a mathematical
Water Flow Modeling model designed for evaluating groundwater system parameters
D5611 Guide for Conducting a Sensitivity Analysis for a and stresses by minimizing the differences between computed
Ground-Water Flow Model Application and observed system responses.
D5718 GuideforDocumentingaGround-WaterFlowModel 3.2.9.1 Discussion—The term inverse model refers in gen-
Application eral to a numerical code that incorporates a systematic,
automated procedure to minimize the differences between
3. Terminology
observed and computed system responses. This type of model
also is known as a parameter estimation model or parameter
3.1 Definitions—For definitions of terms used in this guide,
see Terminology D653. identification model. Typically, these models are based on
numerical simulation of the groundwater system. Aquifer test
3.2 Definitions of Terms Specific to This Standard:
and tracer test analysis software are often based on analytical
3.2.1 analytical model, n—a model that uses closed form
models of the groundwater system. Since they include auto-
solutions to the governing equations applicable to groundwater
mated procedures to estimate the system parameters, they can
flow and transport processes.
be considered inverse models.
3.2.2 backtracking model, n—an application of a math-
3.2.10 numerical model, n—a model that uses numerical
ematical model for determining groundwater system stresses
methods to solve the governing equations of the applicable
and boundary conditions when the system parameters are
problem.
known and the system responses are either known or bounded.
3.2.11 prediction model, n—an application of a mathemati-
3.2.3 finite difference model, n—a type of approximate,
cal model designed for predicting groundwater system re-
numerical model that uses a discrete technique for solving the
sponses, assuming the system parameters are known. These
governing partial differential equation (PDE) consisting of
modelsarebasedonaso-calledforwardordirectmathematical
replacing the continuous domain of interest by a finite number
formulation of the physical processes.
of regular-spaced mesh or grid points (that is, nodes) repre-
3.2.12 solute transport model, n—an application of a math-
sentingvolume-averagedsubdomainproperties,approximating
ematical model to represent the movement of chemical species
the derivatives of the PDE for each of these points using finite
dissolved in groundwater.
differences, and solving the resulting set of linear or nonlinear
algebraic equations using direct or iterative matrix solving
4. Significance and Use
techniques.
4.1 Groundwater modeling has become an important meth-
3.2.4 finite element model, n—a type of approximate, nu-
odology in support of the planning and decision-making
merical model that uses a discrete technique for solving the
processes involved in groundwater management. Groundwater
governing partial differential equation (PDE) wherein the
models provide an analytical framework for obtaining an
domain of interest is represented by a finite number of mesh or
understanding of the mechanisms and controls of groundwater
grid points (that is, nodes), and information between these
systems and the processes that influence their quality, espe-
points is obtained by interpolation using piecewise continuous
cially those caused by human intervention in such systems.
polynomials. The resulting set of linear or nonlinear algebraic
Increasingly, models are an integral part of water resources
equations is solved using direct or iterative matrix solving
assessment, protection and restoration studies, and provide
techniques.
essential and cost-effective support for planning and screening
3.2.5 functionality, n—of a groundwater modeling code, the
of alternative policies, regulations, and engineering designs
setoffunctionsandfeaturesthecodeofferstheuserintermsof 3
affecting groundwater.
model framework geometry, simulated processes, boundary
4.2 There are many different groundwater modeling codes
conditions, and analytical and operational capabilities.
available, each with their own capabilities, operational charac-
3.2.6 groundwater flow model, n—an application of a math-
teristics, and limitations. If modeling is considered for a
ematical model to represent a regional or site-specific ground-
project, it is important to determine if a particular code is
water flow system.
appropriate for that project, or if a code exists that can perform
3.2.7 groundwater modeling code, n—the nonparameterized
the simulations required in the project.
computer code used in groundwater modeling to represent a
4.3 In practice, it is often difficult to determine the capabili-
nonunique, simplified mathematical description of the physical
ties, operational characteristics, and limitations of a particular
framework, geometry, active processes, and boundary condi-
tions present in a reference subsurface hydrologic system.
National Research Council (NRC), Committee on Ground-Water Modeling
3.2.8 heat transport model, n—an application of a math-
Assessment, Water Science and Technology Board, “Ground-water Models: Scien-
ematical model to represent the movement of heat or energy in
tific and Regulatory Applications,” National Academy Press, Washington, DC,
a groundwater system. 1990.
D6033 − 96 (2008)
groundwater modeling code from the documentation, or even 5.2.3 The mathematical framework.
impossible without actual running the code for situations 5
5.3 Objective-Oriented Classification (see Table 1):
relevant to the project for which a code is to be selected due to
5.3.1 The purpose or objective of a groundwater modeling
incompleteness, poor organization, or incorrectness of a code’s
code can be defined in terms of the applicability of the code to
documentation.
certaintypesofgroundwatermanagementproblems,thecode’s
4.4 Systematic and comprehensive description of a code’s functional use, or its computational output.
features based on an informative classification provides the 5.3.2 Management objectives may include requirements,
necessary basis for efficient selection of a groundwater mod- such as type of problems which may be simulated, type of
eling code for a particular project or for the determination that calculations and level of resolution required, acceptable accu-
no such code exists. This guide is intended to encourage racy, representation of specific management strategies, and
correctness, consistency, and completeness in the description other technical, scientific, social, and economic objectives. In
of the functions, capabilities, and limitations of an existing general, however, it is not practical to develop a standard
groundwater modeling code through the formulation of a code classification and description system based on such manage-
classification system and the presentation of code description ment objectives, as these are taken more easily into account in
guidelines. the code selection process than in the code documentation
phase.
5. Classification of Groundwater Modeling Codes
5.3.3 By design, a code’s functional-use objectives may be
one or more of the following:
5.1 There are many groundwater modeling codes available
designed to simulate, describe, or analyze different types of 5.3.3.1 To enable evaluation of a new theory and related
hypotheses as part of research;
groundwater systems and problems. The descriptive informa-
tion of such software can be divided in three groups. 5.3.3.2 To be used as a tool in education and demonstration
of principles;
5.1.1 General Software Information , includes such items as
code name, version number, and release date of current 5.3.3.3 To be used as a generic tool for groundwater system
characterization;
version; development team; supported computer platform(s)
and requirements; software language(s) and requirements; 5.3.3.4 To be used as a generic tool for engineering design
(for example, well fields, excavations, remedial actions, and so
availability conditions and distributors; and software support
and maintenance; forth);
5.3.3.5 To be used as a site- or problem-dedicated tool
5.1.2 Simulation System Information , refers to descriptions
of the nature of the systems that can be simulated, the method (including site- or problem-specific data); and,
5.3.3.6 To be used as a generic or dedicated tool for policy
of simulation, the computed variables, and the required model
input; and, or management strategy screening.
5.3.4 A classification based on computational output in-
5.1.3 Performance Evaluation Information, including the
results of code verification, analysis of the sensitivity of the cludes the following categories:
dependentvariablefornaturalvariationsinsystemcontrolsand 5.3.4.1 Screening or Ranking Models—Facilitating qualita-
tive evaluation of relative merits and disadvantages of various
system parameters (that is, system input), and listing of
operational limitations. management or engineering alternatives;
5.3.4.2 Prediction Models—Predicting system responses,
5.2 To describe systematically the features of groundwater
assuming the system parameters (for example, hydraulic con-
modeling codes, a classification is used based on simulation
ductivity, storativity) and system stresses (for example, bound-
system information (see Table 1). Three primary categories of
5 ary conditions) are known (that is, independent field informa-
code features can be distinguished as follows:
tion); the most common variables computed by prediction
5.2.1 The (design) purpose(s) or objective(s) of the soft-
models are hydraulic head, draw
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