ASTM D6033-96(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 6033 – 96 (Reapproved 2002)
Standard Guide for
Describing the Functionality of a Ground-Water Modeling
Code
This standard is issued under the fixed designation D 6033; 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 encounter situations in which no existing code is applicable. In
those cases, the systematic description of modeling needs may
1.1 This guide presents a systematic approach to the classi-
be based on the methodology presented in this guide.
fication and description of computer codes used in ground-
1.5 This guide is one of a series of guides on ground-water
water modeling. Due to the complex nature of fluid flow and
modeling codes and their applications, such as Guides D 5447,
biotic and chemical transport in the subsurface, many different
D 5490, D 5609, D 5610, D 5611, and D 5718.
types of ground-water modeling codes exist, each having
1.6 Complete adherence to this guide may not be feasible.
specific capabilities and limitations. Determining the most
For example, research developments may result in new types
appropriate code for a particular application requires a thor-
of codes not yet described in this guide. In any case, code
ough analysis of the problem at hand and the required and
documentation should contain a section containing a complete
available resources, as well as a detailed description of the
description of a code’s functions, features, and capabilities.
functionality of potentially applicable codes.
1.7 This guide offers an organized collection of information
1.2 Typically, ground-water modeling codes are nonparam-
or a series of options and does not recommend a specific
eterized mathematical descriptions of the causal relationships
course of action. This document cannot replace education or
among selected components of the aqueous subsurface and the
experience and should be used in conjunction with professional
chemical and biological processes taking place in these sys-
judgment. Not all aspects of this guide may be applicable in all
tems. Many of these codes focus on the presence and move-
circumstances. This ASTM standard is not intended to repre-
ment of water, dissolved chemical species and biota, either
sent or replace the standard of care by which the adequacy of
under fully or partially saturated conditions, or a combination
a given professional service must be judged, nor should this
of these conditions. Other codes handle the joint movement of
document be applied without consideration of a project’s many
water and other fluids, either as a gas or a nonaqueous phase
unique aspects. The word “Standard” in the title of this
liquid, or both, and the complex phase transfers that might take
document means only that the document has been approved
place between them. Some codes handle interactions between
through the ASTM consensus process.
the aqueous subsurface (for example, a ground-water system)
and other components of the hydrologic system or with
2. Referenced Documents
nonaqueous components of the environment.
2.1 ASTM Standards:
1.3 The classification protocol is based on an analysis of the
D 653 Terminology Relating to Soil, Rock, and Contained
major function groups present in ground-water modeling
Fluids
codes.Additionalcodefunctionsandfeaturesmaybeidentified
D 5447 Guide for Application of a Ground-Water Flow
in determining the functionality of a code.Acomplete descrip-
Model to a Site-Specific Problem
tion of a code’s functionality contains the details necessary to
D 5490 Guide for Comparing Ground-Water Flow Model
understand the capabilities and potential use of a ground-water
Simulations to Site-Specific Information
modeling code. Tables are provided with explanations and
D 5609 Guide for Defining Boundary Conditions in
examplesoffunctionsandfunctiongroupsforselectedtypesof
Ground-Water Flow Modeling
codes. Consistent use of the descriptions provided in the
D 5610 Guide for Defining Initial Conditions in Ground-
classification protocol and elaborate functionality analysis
Water Flow Modeling
form the basis for efficient code selection.
D 5611 Guide for Conducting a Sensitivity Analysis for a
1.4 Although ground-water modeling codes exist for simu-
Ground-Water Flow Model Application
lation of many different ground-water systems, one may
D 5718 Guide for Documenting a Ground-Water Flow
Model Application
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock
and is the direct responsibility of Subcommittee D18.21 on Ground Water and
Vadose Zone Investigations.
Current edition approved Oct. 10, 1996. Published May 1997. Annual Book of ASTM Standards, Vol 04.08.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6033 – 96 (2002)
3. Terminology models of the ground-water system. Since they include auto-
mated procedures to estimate the system parameters, they can
3.1 Definitions—For definitions of terms used in this guide,
be considered inverse models.
see Terminology D 653.
3.2.10 numerical model, n—a model that uses numerical
3.2 Definitions of Terms Specific to This Standard:
methods to solve the governing equations of the applicable
3.2.1 analytical model, n—a model that uses closed form
problem.
solutions to the governing equations applicable to ground-
3.2.11 prediction model, n—an application of a mathemati-
water flow and transport processes.
cal model designed for predicting ground-water system re-
3.2.2 backtracking model, n—an application of a math-
sponses, assuming the system parameters are known. These
ematical model for determining ground-water system stresses
modelsarebasedonaso-calledforwardordirectmathematical
and boundary conditions when the system parameters are
formulation of the physical processes.
known and the system responses are either known or bounded.
3.2.12 solute transport model, n—an application of a math-
3.2.3 finite difference model, n—a type of approximate,
ematical model to represent the movement of chemical species
numerical model that uses a discrete technique for solving the
dissolved in ground water.
governing partial differential equation (PDE) consisting of
replacing the continuous domain of interest by a finite number
4. Significance and Use
of regular-spaced mesh or grid points (that is, nodes) repre-
sentingvolume-averagedsubdomainproperties,approximating
4.1 Ground-water modeling has become an important meth-
the derivatives of the PDE for each of these points using finite
odology in support of the planning and decision-making
differences, and solving the resulting set of linear or nonlinear
processes involved in ground-water management. Ground-
algebraic equations using direct or iterative matrix solving
water models provide an analytical framework for obtaining an
techniques.
understandingofthemechanismsandcontrolsofground-water
3.2.4 finite element model, n—a type of approximate, nu-
systems and the processes that influence their quality, espe-
merical model that uses a discrete technique for solving the
cially those caused by human intervention in such systems.
governing partial differential equation (PDE) wherein the
Increasingly, models are an integral part of water resources
domain of interest is represented by a finite number of mesh or
assessment, protection and restoration studies, and provide
grid points (that is, nodes), and information between these
essential and cost-effective support for planning and screening
points is obtained by interpolation using piecewise continuous
of alternative policies, regulations, and engineering designs
polynomials. The resulting set of linear or nonlinear algebraic
affecting ground water.
equations is solved using direct or iterative matrix solving
4.2 There are many different ground-water modeling codes
techniques.
available, each with their own capabilities, operational charac-
3.2.5 functionality, n—of a ground-water modeling code,
teristics, and limitations. If modeling is considered for a
the set of functions and features the code offers the user in
project, it is important to determine if a particular code is
terms of model framework geometry, simulated processes,
appropriate for that project, or if a code exists that can perform
boundary conditions, and analytical and operational capabili-
the simulations required in the project.
ties.
4.3 In practice, it is often difficult to determine the capabili-
3.2.6 ground-water flow model, n—an application of a
ties, operational characteristics, and limitations of a particular
mathematical model to represent a regional or site-specific
ground-water modeling code from the documentation, or even
ground-water flow system.
impossible without actual running the code for situations
3.2.7 ground-water modeling code, n—the nonparameter-
relevant to the project for which a code is to be selected due to
ized computer code used in ground-water modeling to repre-
incompleteness, poor organization, or incorrectness of a code’s
sent a nonunique, simplified mathematical description of the
documentation.
physical framework, geometry, active processes, and boundary
4.4 Systematic and comprehensive description of a code’s
conditionspresentinareferencesubsurfacehydrologicsystem.
features based on an informative classification provides the
3.2.8 heat transport model, n—an application of a math-
necessary basis for efficient selection of a ground-water mod-
ematical model to represent the movement of heat or energy in
eling code for a particular project or for the determination that
a ground-water system.
no such code exists. This guide is intended to encourage
3.2.9 inverse model, n—an application of a mathematical
correctness, consistency, and completeness in the description
model designed for evaluating ground-water system param- of the functions, capabilities, and limitations of an existing
eters and stresses by minimizing the differences between
computed and observed system responses.
3.2.9.1 Discussion—The term inverse model refers in gen-
National Research Council (NRC), Committee on Ground-Water Modeling
eral to a numerical code that incorporates a systematic,
Assessment, Water Science and Technology Board, “Ground-water Models: Scien-
automated procedure to minimize the differences between
tific and Regulatory Applications,” National Academy Press, Washington, DC,
observed and computed system responses. This type of model
1990.
van der Heijde, P. K. M., and Kanzer, D. A., “Ground-water Model Testing:
also is known as a parameter estimation model or parameter
Systematic Evaluation and Testing of Code Functionality, Performance, and
identification model. Typically, these models are based on
Applicability to Practical Problems,” EPA/600/R-97/007, R.S. Kerr Environmental
numerical simulation of the ground-water system. Aquifer test
Research Laboratory, U.S. Environmental Protection Agency, Ada, Oklahoma,
and tracer test analysis software are often based on analytical 1996.
D 6033 – 96 (2002)
ground-water modeling code through the formulation of a code 5.3.3.3 Tobeusedasagenerictoolforground-watersystem
classification system and the presentation of code description characterization;
guidelines. 5.3.3.4 To be used as a generic tool for engineering design
(for example, well fields, excavations, remedial actions, and so
5. Classification of Ground-Water Modeling Codes
forth);
5.1 There are many ground-water modeling codes available
5.3.3.5 To be used as a site- or problem-dedicated tool
designed to simulate, describe, or analyze different types of
(including site- or problem-specific data); and,
ground-water systems and problems. The descriptive informa-
5.3.3.6 To be used as a generic or dedicated tool for policy
tion of such software can be divided in three groups.
or management strategy screening.
5.1.1 General Software Information, includes such items as
5.3.4 A classification based on computational output in-
code name, version number, and release date of current
cludes the following categories:
version; development team; supported computer platform(s)
5.3.4.1 Screening or Ranking Models—Facilitating qualita-
and requirements; software language(s) and requirements;
tive evaluation of relative merits and disadvantages of various
availability conditions and distributors; and software support
management or engineering alternatives;
and maintenance;
5.3.4.2 Prediction Models—Predicting system responses,
5.1.2 Simulation System Information, refers to descriptions
assuming the system parameters (for example, hydraulic con-
of the nature of the systems that can be simulated, the method
ductivity, storativity) and system stresses (for example, bound-
of simulation, the computed variables, and the required model
ary conditions) are known (that is, independent field informa-
input; and,
tion); the most common variables computed by prediction
5.1.3 Performance Evaluation Information, including the
models are hydraulic head, drawdown, pressure, velocity
results of code verification, analysis of the sensitivity of the
(vector), fluid flux (vector), stream- or pathlines, isochrones,
dependentvariablefornaturalvariationsinsystemcontrolsand
contaminant fronts, contaminant concentration (in both liquid
system parameters (that is, system input), and listing of
and solid phase), solute flux (vector), temperature, enthalpy,
operational limitations.
heat flux (vector), location of (saltwater/freshwater) interface,
5.2 To describe systematically the features of ground-water
water balance, and chemical mass balance.
modeling codes, a classification is used based on simulation
5.3.4.3 Backtracking Models—Determining system stresses
system information (see Table 1). Three primary categories of
and boundary conditions when the system parameters are
code features can be distinguished as follows:
known (from observation) and the system responses are either
5.2.1 The (design) purpose(s) or objective(s) of the soft-
known or bounded, used to determine, among others, location
ware;
and duration of a contaminant release, to reconstruct well-field
5.2.2 The nature of the ground-water system that can be
pumping history, or to estimate aquifer recharge rates.
simulated with the software; and,
5.2.3 The mathematical framework.
TABLE 1 Classification Categories for Ground-Water Modeling
5 6
5.3 Objective-Oriented Classification (see Table 1): Software
5.3.1 The purpose or objective of a ground-water modeling
Code Design Objectives
code can be defined in terms of
...