EPA600/R-93-118
vvEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-93/118
May 1993
,-, /'' < _.
Compilation of
Ground-Water Models
ENVIRONMENTAL
PROTECTION
AGENCY
DALLAS, TEXAS
LIBRARY
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EPA/600/R-93/118
May 1993
COMPILATION OF GROUND-WATER MODELS
by
Paul K.M. van der Heijde
International Ground Water Modeling Center
Institute for Ground-Water Research and Education
Colorado School of Mines
Golden, Colorado 80401
and
Osman A. Elnawawy
Indiana University/Purdue University at Indianapolis
Indianapolis, Indiana 46204
for
Holcomb Research Institute
Butler University
Indianapolis, Indiana 46208
CR-815363
Project Officer
Joseph R. Williams
Extramural Activities and Assistance Division
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
/yS Printed on Recycled Paper
••-%-/
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DISCLAIMER NOTICE
The information in this document has been funded in part by the United States Environmental
Protection Agency under cooperative agreement # CR-815363 with the Holcomb Research Institute, Butler
University, Indianapolis, Indiana. It has been subjected to the Agency's peer and administrative review, and
it has been approved for publication as an EPA document. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
All research projects making conclusions or recommendations based on environmentally related
measurements and funded by the Environmental Protection Agency are required to participate in the Agency
Quality Assurance Program. This project did not involve environmentally related measurements and did not
involve a Quality Assurance Project Plan.
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FOREWORD
EPA is charged by Congress to protect the Nation's land, air, and water systems. Under a mandate
of national environmental laws focused on air and water quality, solid waste management and the control
of toxic substances, pesticides, noise and radiation, the Agency strives to formulate and implement actions
which lead to a compatible balance between human activities and the ability of natural systems to support
and nurture life.
The Robert S. Kerr Environmental Research Laboratory is the Agency's center of expertise for
investigation of the soil and subsurface environment. Personnel at the laboratory are responsible for
management of research programs to: (a) determine the fate, transport and transformation rates of
pollutants in the soil, unsaturated and the saturated zones of the subsurface environment; (b) define the
processes to be used in characterizing the soil and subsurface environment as a receptor of pollutants;
(c) develop techniques for predicting the effect of pollutants on ground water, soil and indigenous
organisms; and (d) define and demonstrate the applicability and limitations of using natural processes,
indigenous to the soil and subsurface environment, for the protection of this resource.
Ground-water modeling, as a computer-based methodology for mathematical analysis, is a tool for
investigating and managing the mechanisms and controls of ground-water systems. These modeling codes
are used for the evaluation of policies, actions, and designs that may affect such systems. Models are
playing an important role in the determination of the physical and economical effects of proposed ground-
water protection policy alternatives, and thus the protection of human and ecological health.
The model selection process for appropriate codes is a vital step to conducting these investigative
and management alternatives for ground-water systems. This report presents the methodology used by
the International Ground Water Modeling Center (IGWMC) to classify, evaluate and manage descriptive
information regarding ground-water modeling codes for the purpose of model selection. Furthermore, the
report provides an overview of available ground-water modeling codes and their major characteristics by
presenting the classification approach taken by the IGWMC, and discusses different types of models and
mathematical approaches invoked for developing the models. Separate sections discuss and review the
different categories of ground-water models: flow models, transport models, chemical reaction models,
stochastic models, models for fractured rock, and ground-water management models. The appendices
include a listing and description from the IGWMC MARS database of selected models from each category.
Clinton W. Hall
Director
Robert S. Kerr Environmental
Research Laboratory
in
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ABSTRACT
Ground-water modeling is a computer-based methodology for mathematical analysis of the
mechanisms and controls of ground-water systems, and for the evaluation of policies, actions, and designs
that may affect such systems. In addition to satisfying scientific interest in the workings of subsurface fluid
flow and fluid-related mass-transfer and transformation processes, models assist in analyzing the responses
of subsurface systems to variations in both existing and potential new stresses. Models play an increasingly
dominant role in the determination of the physical and economical effects of proposed ground-water
protection policy alternatives, and thus in the protection of human and ecological health. Furthermore,
computer models are essential tools in the screening of alternative remediation technologies and strategies
in cleaning up ground-water systems polluted in the (recent) past, in the sound design of ground-water
resource development schemes for water supply, and for other land use modifications affecting ground-water
systems.
To be able to select a computer code appropriate for the type of analysis to be performed, ground-
water modelers need to have an overview of available computer code - and their characteristics. This report
presents the methodology used by the International Ground Water Modeling Center to classify, evaluate and
manage descriptive information regarding ground-water modeling codes for the purpose of model selection.
Furthermore, the report provides an overview of available ground-water modeling codes and their major
characteristics.
The report includes a section that defines ground-water modeling, presents the classification
approach taken by the International Ground Water Modeling Center (IGWMC), and discusses different types
of models and the mathematical approaches invoked for developing the models. Separate sections discuss
and review the different categories of ground-water models: flow models, transport models, chemical
reaction models, stochastic models, models for fractured rock, and ground-water management models. The
appendices include a listing and description from the IGWMC MARS database of selected models from each
category.
iv
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BACKGROUND AND REPORT ORGANIZATION
In the mid-1970's, by request of the Scientific Committee on Problems of the Environment (SCOPE),
part of the International Council of Scientific Unions (ICSU), the Holcomb Research Institute (HRI) at Butler
University, Indianapolis, Indiana, carried out a ground-water modeling assessment. This international study,
funded in large part by the U.S. Environmental Protection Agency-(EPA) through its R.S. Kerr Environmental
Research Laboratory in Oklahoma, resulted in a report published by the American Geophysical Union (AGU)
in its series, Water Resources Monographs. In 1985 a second edition of this monograph (AGU Monograph
5) was published, based on information collected at HRI through its International Ground Water Modeling
Center (IGWMC) from its inception in 1978 until December 1983.
The Center was established at HRI as an international clearinghouse for ground-water models and
a technology transfer center in ground-water modeling. Since 1983 the Center has been linked to the TNO
Institute of Applied Geoscience, Delft, The Netherlands, which operates the European office of the IGWMC.
Due to the closing of Holcomb Research institute by Butler University in the Summer of 1991, the IGWMC
relocated its US office to the Colorado School of Mines (CSM), Golden, Colorado.
The Center operates a clearinghouse for ground-water modeling software, organizes and conducts
short courses and seminars, and carries out a research program to advance the quality of modeling in
ground-water management, in support of the Center's technology transfer functions. The Center's
International Technical Advisory Committee provides guidance and active support to its program.
The present report contains the result of research and information processing activities performed
by the IGWMC under a research and technology transfer cooperative agreement with the U.S. Environmental
Protection Agency, initiated in 1988. Three other reports have been prepared under this cooperative
agreement:" Modeling Multiphase Flow and Transport" by Aly I. El-Kadi, Osman A. Elnawawy, Pamela Kobe,
and Paul K.M. van der Heijde, submitted to EPA in May 1991 (IGWMC Report Number GWMI 91-04),
"Ground-Water Management Models", by Aly I. El-Kadi, Osman A. Elnawawy, and Paul K.M. van der Heijde,
submitted to EPA in December 1991 (IGWMC Report Number GWMI 91-05), and "Quality Assurance and
Quality Control in the Development and Application of Ground-Water Models" by Paul K.M. van der Heijde
and Osman A. Elnawawy, submitted to EPA in September 1992 (IGWMC Report Number GWMI 92-03). The
current report, together with the reports on management models and multiphase flow and transport, provides
an overview of the status of major types of ground-water models. These reports present an update of
Chapter 5 and the appendices of the report "Groundwater Modeling: An Overview and Status Report,"
prepared in 1988 under a previous cooperative agreement with the US EPA (Report EPA/600/2-89/028).
The review of models has been based on information gathered by the IGWMC through research and
interviews on an on-going basis since 1978. To manage the rapidly growing amount of information, IGWMC
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maintains a descriptive model information system, MARS (Model Annotation Search and Retrieval System).
Currently, this database is installed on a microcomputer operating under MS-DOS. Detailed information on
the reviewed models is presented in a series of tables, preceded by an introduction on model classification
and principal characteristics of the described models.
The authors are grateful to Aly I. El-Kadi, Stan A. Williams, Milovan S. Beljin, and P. Srinivasan for
their past contributions to the IGWMC model assessment studies; to Richard E. Rice for his contributions
on geochemical equilibrium models; to Deborah L Cave for her assistance in collecting model information
and reviewing hydrogeochemical modeling literature; to Michael Stibitz for his assistance in processing
model information; to David Dillon, Jeffrey Lewis and Manjit Trehan for database programming assistance;
to Mary Willis, Amy Maxwell and Mary Pigman for word processing; to James N. Rogers for manuscript
editing; and to Colleen Baker for graphics. Furthermore, authors wish to acknowledge the
administrative and technical support provided by the Colorado School of Mines in completing this report.
Paul K.M. van der Heijde
Golden, Colorado
VI
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CONTENTS
Foreword iii
Abstract iv
Background and Report Organization v
Figures x
Tables x
1. INTRODUCTION 1
1.1 Model Classification 3
1.1.1 Objective-Oriented Classification 5
1.1.2 Classification Based on the Nature of the Ground-Water System 6
1.1.3 Classification Based on Mathematical Approaches 10
1.2 Model Information System 11
1.2.1 Historic Development 12
1.2.2 Database Management 14
1.2.3 Identification and Annotation of Models 15
2. FLOW MODELS FOR POROUS MEDIA 17
2.1 Mathematical Formulation for Saturated Flow 18
2.2 Mathematical Formulation for Unsaturated Flow 18
2.3 Multiphase Row 19
2.3.1 Modeling Multiphase Flow 24
3. TRANSPORT MODELS FOR POROUS MEDIA 29
3.1 Solute Transport 29
3.1.1 Advection-Dispersion Equation 30
3.2 Heat Transport 37
3.2.1 Heat Transport Equation 38
3.3 Vapor Transport 40
3.3.1 Physicochemical and Biological Processes 40
3.3.2 Laboratory and Field Studies 41
3.3.3 Numerical Model Studies 42
4. HYDROGEOCHEMICAL MODELS 44
4.1 Gibbs Free Energy and Equilibrium Constants 45
4.2 Electrolytes and Activity Coefficients 46
4.3 Oxidation-Reduction Reactions 47
VII
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CONTENTS - continued
4.4 Limitations of Hydrochemical Models 48
4.5 Modeling Non-Dilute Solutions 49
4.6 Numerical Solution Methods 50
5. STOCHASTIC MODELS 51
6. MODELS FOR FRACTURED ROCK 53
7. GROUND-WATER MANAGEMENT 56
7.1 Solution Approaches 56
7.2 Ground-water Management Models 58
8. CONCLUSION AND DISCUSSION 60
9. REFERENCES 62
APPENDIX 85
A. Saturated Flow
A-1. Analytical Models
A-2. Numerical Models for Two-Dimensional Flow in Horizontal or Vertical Plane
A-3. Numerical Models for Three-Dimensional Flow
A-4. Analytical Inverse Models (Aquifer Test Models)
A-5. Numerical Inverse Models
A-6. Pathline Models
B. Variably Saturated Flow
B-1. Numerical Models
B-2. Parameter Estimation Models
C. Solute Transport
C-1. Analytical Models for Saturated Zone
C-2. Two-Dimensional Numerical Models for Saturated Zone
C-3. Three-Dimensional Numerical Models for Saturated Zone
C-4. Models for Unsaturated Zone
viii
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CONTENTS - continued
D. Heat Transport
E. Gas Flow and Vapor Transport
F. Row and Transport in Fractured Rock
G. Hydrogeochemical Models
H. Optimization Models for Ground-water Management
I. Multiphase Row
J. Cross-reference Table for Appendix A-l
IX
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FIGURES
Number Page
1. Schematic diagram of a chemical spill of a volume less than the retention capacity
of the partially saturated soil profile (from Schwille 1984) 20
2. Schematic diagram of a lighter-than-water chemical spill of a volume greater than
the retention capacity of the soil (from Schwille 1984) 21
3. Schematic diagram of a heavier-than-water chemical spill of a volume greater than
the retention capacity of the soil (from Schwille 1984) 22
4. Funicular zones for three immiscible fluids 23
5. Schematized vertical infiltration and horizontal spreading of the bulk of a low
density hydrocarbon atop the water table (after Dracos 1978) 25
6. Oil bulk zone and spreading of dissolved components in ground water from a field
experiment by Bartz and Kass (after Dracos 1978) 26
TABLES
Number Page
1. Ground-Water Model Categories 4
2. Important Processes In Ground-Water Modeling 9
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I. INTRODUCTION
Ground-water modeling is a computer-based methodology for mathematical analysis of the mechanisms
and controls of ground-water systems, and for the evaluation of policies, actions, and designs that may
affect such systems (van der Heijde et al. 1988). In addition to satisfying scientific interest in the workings
of subsurface fluid flow and fluid-related mass-transfer and transformation processes, models assist in
analyzing the responses of subsurface systems to variations in both existing and potential new stresses.
Models play an increasingly dominant role in the determination of the physical and economical effects of
proposed ground-water protection policy alternatives, and thus in the protection of human and ecological
health. Furthermore, computer models are essential tools in the screening of alternative remediation
technologies and strategies in cleaning up ground-water systems polluted in the (recent) past, in the sound
design of ground-water resource development schemes for water supply, and for other land use
modifications affecting ground-water systems.
Although a consensus may exist as to what ground-water modeling entails, the definition of a "model"
perse is somewhat nebulous. In hydrogeology, the term "ground-water model" has become synonymous
with conceptual ground-water models, mathematical ground-water models (including analytical and
numerical models), computer models, and simulation models. Furthermore, the term "ground-water model"
may apply to either a generic model or computer code (without site-specific data) or the representation of
a site-specific system using such a generic code. The International Ground Water Modeling Center defines
a model as a non-unique, simplified, mathematical description of an existing ground-water system, coded
in a programming language, together with a quantification of the ground-water system the code simulates
in the form of boundary conditions, system parameters, and system stresses. The generic computer code
used in this problem-specific system simulation is sometimes referred to as a (ground-water) simulation code
or a generic ground-water model. This use of the term "ground-water model" includes both the saturated
and unsaturated zones.
Ground-water models are generally intended to perform as practical, descriptive, and predictive
problem-solving tools. Most ground-water models are mathematical models in which the causal
relationships among various components of the ground-water system and between the system and its
environment are quantified and expressed in terms of mathematics and uncertainty of information.
Mathematical models range from rather simple, empirical expressions to complex mechanistic, multi-equation
formulations. As the problems encountered in protecting and remediating ground-water resources are highly
complex in nature, their study requires cooperation between many disciplines. Routinely, simulations of the
complex ground-water systems involved require characterization of hydrology, physical transport processes,
geochemistry, contaminant chemistry and biochemistry in the near-surface and deep underground.
Therefore, contemporary ground-water modeling is highly multidisciplinary in nature.
Models are useful tools for understanding the structure and dynamics of ground-water systems and
the processes that influence their composition. Modeling serves as a means to ensure orderly interpretation
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of the data describing a ground-water system, and to ensure that this interpretation is a consistent
representation of the system. It can also provide a quantitative indicator for efficient resource utilization
when additional field data collection is required and financial resources are limited. Finally, models can be
used in what is often called the predictive mode by analyzing the response a system is expected to show
when existing stresses vary and new ones are introduced, or by optimizing the response of the system by
varying the stresses in a systematic way. Increasingly, the objectives behind the ground-water modeling
efforts are protection and improvement of human health through providing good quality drinking water and
reducing the risks resulting from exposure to contaminated ground water.
Where precise aquifer and contaminant characteristics have been reasonably well established, ground-
water models may provide a viable, if not the only, method to predict contaminant transport and fate, locate
areas of potential environmental risk, identify pollution sources, and assess possible remedial actions. Some
examples in which mathematical models have assisted in the management of ground-water protection
programs are (van der Heijde et al. 1988):
• Determining or evaluating the need for regulation of specific waste disposal, agricultural, and
industrial practices
• Analyzing policy impacts, as in evaluating the consequences of setting regulatory standards and
rules
• Assessing exposure, hazard, damage, and health risks
• Evaluating reliability, technical feasibility and effectiveness, cost, operation and maintenance, and
other aspects of waste disposal facility designs and of alternative remedial actions
• Providing guidance in siting new facilities and in permit issuance and petitioning
• Developing aquifer or well head protection zones
• Assessing liabilities such as post-closure liability for waste disposal sites.
Computer-based ground-water modeling began in the mid 1960's and has gradually grown into a widely
accepted and applied decision-support tool. In the last few years, modeling has been made easier, faster
and "flashier" by rapidly evolving computer hardware and software technologies. The widespread availability
of powerful desktop microcomputers and user-oriented software interfaces has made running ground-water
computer codes a rather mundane task in hydrogeological assessments. The mechanics of entering data,
running simulations, and creating high-quality graphics have become less time-consuming and less complex
due to the availability of various, extensively supported window environments and expanded functionality,
easy-to-debug, programming languages. These high-powered software development systems integrate
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editing, compiling, and debugging functions with additional programming tools and libraries allowing efficient
development of flexible, menu-driven software while facilitating achievement of high quality-assurance goals.
Increased portability of the software due to the development of multi-platform operating systems such as
UNIX, and standardization of high-level programming languages (e.g., FORTRAN 90) and the subsequent
release of new compilers, makes it possible that software development groups are able to continue to
improve the simulation components of the software. Furthermore, the use of object-oriented programming
holds the promise of more flexibility regarding post-development expansion and maintenance, and in overall
reliability and portability of the software (Gibson 1990, Mackie 1991).
Recently, geographical information systems (GIS) have become prominent tools in model preparation
and evaluation of modeling results. Automatic allocation of model parameters is facilitated by overlaying
the spatially organized geological and hydrological parameters with a model-defined computational mesh.
The significance of the results of model simulations in the final decision-making process can be further
enhanced by importing the raster- or vector-based simulation results back into a GIS and combining these
with background maps of the area under study and other spatial information important for decision-making.
However, the reduction in time and effort in modeling due to new software developments does not
mean that modeling has become a simple task; in fact, modeling is becoming more challenging as ground-
water specialists are able to deal with increasingly complex mathematical descriptions of natural systems
and resource management problems. In addition, these problems can be studied in much more detail by
using high-order spatial and temporal resolution.
In-depth treatment of the theoretical basis of ground-water models can be found in NRC (1990), among
others. Extensive discussion on modeling methodology is given in van der Heijde et al. (1988) and NRC
(1990).
1.1 MODEL CLASSIFICATION
There are various kinds of ground-water models, designed to simulate different types of ground-water
systems, and able to compute different variables. To identify the main attributes of a particular model, a
classification system is needed. An early effort to classify ground-water models was published by Bachmat
et al. (1978). This classification approach has been used, modified and expanded by various researchers
(Mercer and Faust 1981, Simmons and Cole 1985, NRC 1990). The classification system presented here
has been developed to enable the International Ground Water Modeling Center to systematically describe
ground-water models in its computerized information system (see Table 1).
Ground-water models can be divided into various categories, depending on the purpose of the model,
the nature of the ground-water system and the mathematical method(s) employed.
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TABLE 1. GROUND-WATER MODEL CATEGORIES.
1. Objective-based model categories
• applicability of the model to certain
types of ground-water management
problems
• code development objective(s)
- research
- education/demonstration
- general use
calculated variables
- screening/ranking
- prediction
- backtracking
- inverse or parameter estimation
- optimization
2. Processed-based model categories
• flow
- saturated flow
- unsaturated flow
- vapor transport
- multi-phase flow (water/air or vapor;
water/NAPL; water/steam; salt
water/fresh water
• heat transport
• hydrogeochemica! speciation
3. Physical-system-characteristics-based model categories
• hydrogeological system
- water-saturated vs. partially saturated
- porous medium vs. fractured rock
- single, simple system vs.
multilayered system of aquifers
and aquitards or soils
- (leaky-) confined vs. phreatic aquifer
conditions
- heterogeneity, anisotropy
- site, local, regional scale
• flow conditions
- laminar vs. turbulent
- steady-state vs. time-varying
conditions
• fluid conditions
- type of fluid (water, NAPL, vapor,
steam)
solute transport and fate
- conservative
- nonconservative
- coupled with hydrogeochemistry
matrix deformation due to fluid injection
or withdrawal
coupling with external systems (e.g.,
surface water, plant uptake,
atmosphere)
- varying vs. constant fluid viscosity
- varying vs. constant fluid density
- compressible vs. non-compressible
fluid
boundary location and conditions
- type of boundary condition (1st, 2nd,
3rd; flow, transport)
- physical representation (recharge,
stream, lake, seepage face,
springs, point-.line-, or areal
contaminant/heat source, diffuse
source)
more
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Table 1 - continued
4. Mathematics
• general nature of equation
- empirical vs. mechanistic
- deterministic vs. stochastic
• dimensionality of equations
• solution method
- analytical
+ single solution
+ superposition
+ semi-analytical solution
solution method - continued
- numerical
+ spatial approximation (finite difference, finite
element, boundary element, method of
characteristics, random particle
movement)
+ time-stepping scheme
+ matrix solution technique
1.1.1 Objective-Oriented Classification
The purpose of a model can be defined in terms of the applicability of the model to certain types of
ground-water management problems, the code development objective(s), or in terms of the variables it
calculates. Examples of modeling objectives from the perspective of ground-water management are:
regional ground-water system characterization for resource development and protection planning
• optimal well-field design for water supply (effectiveness, impact)
protection of well-fields against pollution from within aquifer or through confining layers
construction site or mining site dewatering
• determination of contaminant movement from known source, such as a landfill, impoundment, or
leaky underground storage tank
design of waste storage facility
• exploring optimal design for hydraulic containment of a contaminant plume
design of a pump and treat remediation action
design of an in-situ biorestoration scheme
• design of a ground-water quality monitoring network
risk assessment at a contaminated site
• feasibility study and design of an aquifer thermal storage system (ATES)
assessment of impact of deep-well injection of waste
• screening or ranking of alternative policies, site-related risks, protection priority, engineering
designs, etc.
A classification system based on management objectives should include such aspects as level of
resolution required, accuracy acceptable, and other technical, scientific, social, and economic objectives.
However, in general it is not practical to develop a classification system based on such management
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objectives, as these are more easily taken into account in the code selection process than in model
characterization.
Another objective-based approach is to analyze the development objectives for the model code. One
can distinguish between three major development objectives: (1) to develop an educational tool (educational
model), (2) to study quantitatively the fundamental nature of a ground-water system (research codes), and
(3) to develop a code that can be applied routinely to various site-specific problems (general-use code).
Finally, an objective-based classification approach may be based on the variables which can be
computed with the model. In this case, the major model types are (van der Heijde et a/. 1985): (1)
prediction models designed to predict the system responses, assuming the system parameters and system
stresses are known; (2) backtracking models, determining system stresses when system parameters are
known and the system responses are either known or bounded; and (3) inverse or parameter estimation
models for the evaluation of system parameters when a history of stresses and responses are known. The
most common variables computed by prediction models are hydraulic head, drawdown, pressure, velocity
(vector), fluid flux (vector), stream- or pathlines, isochrones, contaminant fronts, contaminant concentration
(in both liquid and solid phase), solute flux (vector), temperature, enthalpy, heat flux (vector), optimum
location of sources and sinks, location of (saltwater/freshwater) interface, water balance, and chemical mass
balance. Backtracking models are used specifically to determine system stresses and boundary conditions
(e.g location and duration of contaminant source release, well-field pumping history, aquifer recharge rates).
Inverse models are designed to determine the most likely distribution of system and process parameters
(transmissivity, dispersivity, retardation coefficient).
1.1.2 Classification Based on the Nature of the Ground-Water System
The nature of the ground-water system is characterized by the system's hydrogeological characteristics
(i.e. hydrogeologic schematization and geometry, parameter variability in space and time, boundary locations
and conditions, and system stresses) and the physical, chemical, and biological processes that take place
(type of processes, their spatial and temporal characteristics, and their relative importance). Accordingly,
we distinguish between two classification types in describing the ability of models to represent the nature
of the ground-water (or soil-water) system: (1) hydrogeology-based model types, and (2) process-based
model types.
One way to distinguish between different types of ground-water models is based on the kind of
hydrogeologic features they can simulate (see Table 1). Among others, distinction may be made between
various kinds of hydrogeologic conceptualizations or zonings, e.g., saturated zone versus unsaturated zone,
a single aquifer system versus a multilayered system of aquifers and aquitards (see Table 1). Another
distinction is based on scale, e.g., site, local, or regional scale.
A classification based on processes distinguishes between flow, transport (solute and heat), fate of
chemical compounds, phase transfers and other processes (Table 2 lists important processes encountered
in ground-water systems. Flow models simulate the movement of one or more fluids in porous or fractured
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rock. One such fluid is water; the others, if present, can be air, methane, or other vapors (in soil) or
immiscible nonaqueous phase liquids (NAPLs) sometimes having a density distinct from water (LNAPLs,
DNAPLs). A special case of multi-fluid flow occurs when layers of water of distinct density are separated
by a relatively small transition zone, a situation often encountered when sea water intrusion occurs. Most
flow models are based on a mathematical formulation which considers the hydraulic system parameters as
independent field information and hydraulic head and flux as dependent variables. They are used to
calculate steady-state distribution or changes in time in the distribution of hydraulic head or fluid pressure,
drawdown, rate and direction of flow (e.g., determination of streamlines, particle pathways, velocities, and
fluxes), travel times, and the position of interfaces between immiscible fluids (Mercer and Faust 1981, Wang
and Anderson 1982, Kinzelbach 1986, Bear and Verruijt 1987). Inverse flow models simulate the flow field
to calculate the spatial distribution of unknown system parameters using field information on the dependent
variables such as hydraulic head and flux.
Two types of models can be used to evaluate the chemical quality of ground-water (e.g., Jennings ef
a/. 1982, Rubin 1983, Konikow and Grove 1984, Kincaid ef a/. 1984): (1) pollutant transformation and
degradation models, where the chemical and microbial processes are posed independent of the movement
of the pollutants; and (2) solute transport models simulating displacement of the pollutants only
(conservative transport), or including the effects of phase transfers, (bio-)chemical transformation and
degradation processes (transport and fate; non-conservative transport). In fact, one may argue a third type
exists, where a conservative solute transport model is coupled with a hydrogeochemical speciation model
(Hosteller era/. 1988; Kinzelbach era/. 1989; Yeh and Tripathi 1989).
Hydrogeochemical speciation models represent the first type, as they consist solely of a mathematical
description of equilibrium reactions or reaction kinetics (Jenne 1981, Rice 1986). These models, which are
general in nature and are used for both ground water and surface water, simulate chemical processes in
the liquid phase and sometimes between the liquid and solid phase (precipitation-dissolution; sorption) that
regulate the concentration of dissolved constituents. They can be used to identify the effects of temperature,
speciation, sorption, and solubility on the concentrations of dissolved constituents (Jenne 1981).
Solute transport models are used to predict movement and concentration of water-soluble constituents
and radionuclides. A solute transport model requires velocities for the calculation of advective displacement
and spreading by dispersion (Anderson 1984). If the velocity field is constant then it may be either
calculated once using a program module or read into the program as data. If the velocity field is dependent
on time or concentration, then calculation of velocities at each time step is required, either through an
internal flow simulation module or an external, coupled flow module.
The nonconservative solute transport models include some type of solute transformation, primarily
adsorption, radioactive decay, and simple (bio-)chemical transformations and decay (Cherry ef a/. 1984,
Grove and Stollenwerk 1987).
The inclusion of geochemistry in solute transport models is often based on the assumption that the
reaction proceeds instantaneously to equilibrium. Recently, various researchers have become interested
in the kinetic approach that incorporates chemical reactions in transport model. This inclusion of
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geochemistry has focused on single reaction such as ion-exchange or sorption for a small number of
reacting solutes (Rubin and James 1973, Valocchi et a/. 1981, Charbeneau 1981).
In some cases, comprehensive ground-water quality and risk assessment requires the simulation of
temperature variations and their effects on ground-water flow and pollutant transport and fate. In the past,
major heat transport model development focused on high-temperature geothermal systems. More recently,
models have been developed to analyze aquifer thermal energy storage and shallow heat pump systems.
A few highly specialized multipurpose prediction models can handle combinations of heat and solute
transport, or heat transport and rock matrix displacement or solute transport and rock matrix displacement.
Generally, these models solve the system of governing equations in a coupled fashion to provide for analysis
of complex interactions among the various physical, chemical, and biological processes involved.
There are three major types of heat transport models in the subsurface: (1) transport through the fluid
phase only, (2) transport through the solid phase only, and (3) transport through both the fluid and solid
phase of the subsurface. Ground-water modeling deals primarily with model types 1 and 3. Within each
of these two latter groups of models one may distinguish four more types of models: (1) low temperature,
single phase heat transport without phase change (e.g., to evaluate heat-pump efficiencies), (2) low
temperature, dual phase heat transport with two fluids (water and vapor, e.g., in soils), (3) low temperature,
dual phase heat transport with phase change (freezing/thawing, e.g., for studying frost front propagation
in soils), and (4) high-temperature, multi-phase (liquid/vapor) heat transport with phase change
(steam/water; e.g., for evaluation of geothermal exploration potential). Typical processes incorporated
include convection, dispersion, conduction, radiation, evaporation/condensation, and freezing/thawing.
Many models address the interaction between ground-water and the other components of the
hydrologic cycle. These models describe only the inputs and outputs at interfaces with other components
of the hydrologic cycle as dynamic stresses or boundary conditions. Increasingly, models are developed
that simulate the processes in each subsystem in detail (e.g., Morel-Seytoux and Restrepo 1985; Prudic
1989). Two types of models fit this latter category: watershed models and stream-aquifer models
(sometimes called conjunctive use models).
Watershed models customarily have been applied to surface water management of surface runoff,
stream runoff, and reservoir storage. Traditionally, these models did not treat ground-water flow in much
detail, in part because of the wide range of temporal scales involved. The subsurface components in these
models were limited to infiltration and to a lumped, transfer function approach to ground-water (El-Kadi 1983,
1986).
With the growing interest during the 1970s in the conjunctive use and coordinated management of
surface and subsurface water resources by responsible authorities, a new class of models was developed:
the stream-aquifer models, where the flow in both the surface water network and the aquifers present could
be studied in detail. Conjunctive use of water resources is aimed at reducing the effects of hydrologic
uncertainty about the availability of water. For example, artificially recharged aquifers can provide adequate
water supplies during sustained dry periods when surface water resources run out and nonrecharged
aquifers do not provide enough storage.
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TABLE 2. IMPORTANT PROCESSES IN GROUND-WATER MODELING
Flow: Fate:
• single fluid flow • hydrolysis/substitution
• multifluid flow • dissolution/precipitation
- multicomponent • reduction/oxidation
- multiphase • complexation
• laminar flow • radioactive decay
- linear/Darcian • microbial decay/biotransformation
- nonlinear/non-Darcian
• turbulent flow
Phase Transfers:
solid*—»gas: - (vapor) sorption
solid*-* liquid: - sorption
Transport: - ion exchange
• advection/convection • liquid*-»gas -volatilization
• conduction (heat) - condensation
• mechanical dispersion - sublimation
• molecular diffusion
• radiation (heat) Phase Changes:
freezing/thawing
vaporization
(evaporation) /condensation
Conjunctive use models simulate more processes than those included in watershed models.
Important processes include canal seepage, deep percolation from irrigated lands, aquifer withdrawal by
pumping, ground-water inflow to or outflow from adjacent aquifers, evapotranspiration, artificial recharge,
bank storage effects, and deep-well injection (El-Kadi 1986). The inclusion of detailed ground-water flow
processes in watershed models increases significantly the complexity of model computations. Differences
in temporal scale between surface and subsurface processes add to the complexities.
Recently, increased interest in such multi-system modeling has been motivated by the need to
simulate the flow and chemical transport in systems with complex interaction between the surface water and
subsurface water. This includes wetland systems, watersheds subject to nonpoint pollution from the use
of agricultural chemicals, and regional systems where local soil and ground-water pollution contribute to the
quality of surface water bodies. To model this type of problem, transport and fate processes are added to
the multi-system flow models.
The flow and solute transport models may be embedded in a management model. The hydrologic
system is described in terms of objective function(s) and constraints. For example in ground-water hydraulic
management problems, the objective function is aimed at managing ground-water stresses such as pumping
and recharge and the discretized ground-water flow equations are treated as part of the constraint set. The
resulting equations are solved through an optimization technique such as linear and quadratic programming
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(Gorelick 1983, Gorelick et a/. 1983, Kaunas and Haimes 1985, Wagner and Gorelick 1987).
1.1.3. Classification Based on Mathematical Approaches
The classification scheme used by the IGWMC distinguishes three different classes in mathematical
approaches: (1) the general nature of the governing equations; (2) the dimensionality in the space and time
domain (for variables, parameters, and boundary conditions); and (3) the solution method employed.
In terms of spatial dimensionality, models may be capable of simulating systems in one, two, or three
dimensions. In the time domain, they may handle either transient or steady-state simulations or both.
Another distinction in the way models handle parameters spatially is whether the parameter distribution is
lumped or distributed. Lumped parameter models assume that a system may be defined with a single value
for the primary system variables, and the system's input-response function does not necessarily reflect
known physical laws. In distributed-parameter models, the system variables often reflect detailed
understanding of the physical relationships in the system and may be described with a spatial distribution.
System responses may be determined at various locations.
Until recently, most ground-water modeling studies were conducted using deterministic models based
on precise descriptions of cause-and-effect or input-response relationships. Increasingly, however, models
used in ground-water protection programs reflect the probabilistic or stochastic nature of a ground-water
system to allow for spatial and temporal variability of relevant geologic, hydrologic, and chemical
characteristics (US EPA 1986a, El-Kadi 1987, Dagan 1989, NRG 1990).
Most mathematical models used in ground-water management are distributed-parameter models,
either deterministic or stochastic. Their mathematical framework consists of one or more partial differential
equations called field or governing equations, as well as initial and boundary conditions and solution
procedures. Most models used in the field are based on a deterministic description of the processes
governing flow and transport. Other models assume that the processes active in the system are stochastic
in nature and hence the variables may be described by probability distributions. Consequently, system
responses are characterized by statistical distributions estimated by solving the governing equation.
The governing equations for ground-water systems are usually solved either analytically or numerically.
Analytical models contain a closed-form or analytical solution of the field equations subject to specified initial
and boundary conditions. The analytical solution is continuous in space and time. Because of the complex
nature of ground-water problems, the analytical solutions generally are available for problems that entail a
simplifying nature of the ground-water system, its geometry, and external stresses (Walton 1984, van
Genuchten and Alvas 1982).
In numerical models, a discrete solution is obtained in both the space and time domains by using
numerical approximations of the governing partial differential equation. As a result of these approximations,
the conservation of mass is not always assured (because of truncation and round off errors) and needs to
be verified for each application. Spatial and temporal resolution in applying such models is a function of
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study objectives and availability of data. If the governing equations are nonlinear, linearization often
precedes the matrix solution (Remson et al. 1971, Huyakorn and Finder 1983); sometimes solution is
achieved using nonlinear matrix methods such as predictor-corrector or Gauss-Newton (Gorelick 1985).
Various numerical solution techniques are used in ground-water models. They include finite-difference
methods (FD), integral finite-difference methods (IFDM), Galerkin and variational finite-element methods (FE),
collocation methods, boundary (integral) element methods (BIEM or BEM), particle mass tracking methods
(e.g., random walk method [RW]), and the method of characteristics (MOC) (Huyakorn and Finder 1983,
Kinzelbach 1986). Among the most used approaches are finite-difference and finite-element techniques.
In the finite-difference approach a solution is obtained by approximating the derivatives of the PDE. In the
finite-element approach an integral equation is formulated first, followed by the numerical evaluation of the
integrals over the discretized flow or transport domain. The formulation of the solution in each approach
results in a set of algebraic equations which are then solved using direct or iterative matrix methods.
In semi-analytical models, complex analytical solutions are approximated by numerical techniques,
resulting in a discrete solution in either time or space. Models based on a closed-form solution for either
the space or time domain, and which contain additional numerical approximations for the other domain, are
also considered semi-analytical models. An example of the semi-analytic approach is in the use of numerical
integration to solve analytical expressions for streamlines in either space or time (Javandel ef a/. 1984).
Recently, models have been developed for study of two- and three-dimensional regional ground-water
flow under steady-state conditions in which an approximate analytic solution is derived by superposition of
various exact or approximate analytic functions, each representing a particular feature of the aquifer
(Haitjema 1985, Strack 1988, Rumbaugh 1991).
No universal model can solve all kinds of ground-water problems; different types of models are
appropriate for solving different types of problems. It is important to realize that comprehensiveness and
complexity in a simulation do not necessarily equate with accuracy.
1.2 MODEL INFORMATION SYSTEM
This section summarizes the development and operational design of the ground-water model referral
database or computerized data directory MARS (Model Annotation Search and Retrieval System). Also
discussed are the MARS database objectives, database design criteria, and database maintenance and
updating procedures.
One of the IGWMC's primary objectives is assembling, organizing, analyzing, and disseminating
information related to the development and use of computer-based simulation methodology (i.e.,
mathematical models) in response to changing water resources management demands and benefiting from
computer technology development (van der Heijde 1987). Development of information sources, processing
procedures and user feedback, together with an efficient computer-based system for information
management and dissemination is crucial for such a facility to be successful.
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In order to manage efficiently information concerning the rapidly increasing number of models, a
standardized descriptive reporting system has been developed. Each model is described in an uniform way
by a set of annotations describing its purpose, major hydrological, mathematical and operational
characteristics, input requirements, simulative capabilities, level of documentation, availability, and
applicability. A complete model annotation includes comments made by the model author and IGWMC staff
concerning its development, testing, quality assurance and use, as well as names and addresses of users
of the model, and model references.
1.2.1. Historic Development
In 1979, the Center established its first annotated database of information on ground-water models
MARS (Version 1.0). The original descriptors resulted from the evaluation of a list of keywords used in a
ground-water model review study conducted by the Holcomb Research Institute in 1975-1978 under
auspices of SCOPE (Scientific Committee on Problems of the Environment [Bachmat et at. 1978]). The
database was initially implemented on a UNIVAC 90/30 mainframe computer using software specially written
for this purpose in the COBOL language. The information was stored in binary code [(0,1) = (no.yes) using
a list of more than 200 descriptors, and as text fields (van der Heijde and Williams 1989). The data entered
were based on an update of the results of a survey performed during the earlier study (Bachmat et a/. 1978).
In 1982 this database was transferred to a DEC VAX 11/780 minicomputer and implemented with the
VAX-based database management system DATATRIEVE-11. Although the data record structure was
maintained, this conversion was used to add to and improve the list of model descriptors and to review the
database contents resulting in MARS, Version 2.0. Since then, IGWMC staff has continually maintained,
updated, and used the annotation system for storage of new information on ground-water models (covering
all aspects of the aquatic subsurface including unsaturated and multiphase systems), and for retrieval of
information for internal research and in response to external requests.
In the mid-1980s developments in modeling and computer technology led the IGWMC staff to review
the annotation and software system then in use. The identified problem areas included:
various types of models or model capabilities that were not adequately described;
sluggish system behavior, especially when the database was searched;
user interfaces were not intuitive and informative (not user-friendly);
software was difficult to maintain, requiring expertise not always available at IGWMC or its host
organizations;
the system was only transferable to other DEC/VAX systems with DATATRIEVE resident under
the DEC/VMS operating system;
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the software did not allow for decentralized updating of the database contents.
Rapid expansion of the kind of models the Center was asked to provide information on, and the increasing
complexity of the models involved, required the descriptors to be expanded, regrouped, and hierarchically
organized.
Modifications implemented included increasing the level of detail in the description of models for heat
transport, transport of reactive solutes, transport in deformable and fractured rock and soils,
biotransformation in subsurface transport, and optimal conjunctive use of ground-water and surface water.
Categories to be added included hydrogeochemical models, ground-water parameter identification, and
integral modeling of quantitative and qualitative aspects of ground-water and surface water systems.
The new system then would cover all subsurface flow and transport models including multiphase flow
and vapor transport, and models simulating surface water/ground-water interaction and movement of water
and dissolved chemicals between the subsurface and the atmosphere.
Furthermore, the Center needed a performance evaluation system to document usability and reliability
of the models.
Because current users only indirectly access the Center's modeling information databases, the need
to improve access has been recognized. One way to meet this need would be to make the database
available in the microcomputer environment. However, the Center's experience has been that many current
users of its model information service are primarily interested in selecting a model for a particular
application. Often, these users are not familiar with the variety of available models or with the selection
process, thus requiring IGWMC staff to provide additional assistance in analyzing the model requirements.
In the design of the new version of the model information management system, procedures have been
developed to facilitate such assistance, either provided directly by the Center's staff, or indirectly through
implementation of new technologies, i.e. an experimental knowledge-based advisory system.
The new system has been implemented on a microcomputer operating under MS-DOS in the form
of a relational database programmed in TurboPascal™ version 5.0 from Borland (van der Heijde and Williams
1989).
Based on the analysis of the needs for information on ground-water models, five types of potential
model use have been identified:
application to field problems in support of policy-making and resource management decisions,
analyzing field and laboratory experiments as part of a research program;
as basis for new model formulations and software development;
in education regarding modeling principles and in training in the use of models;
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verification of and comparison with other models.
The content and structure of the database is thus a consequence of its primary objective: identification
of models for any of the above uses. Furthermore, the following design criteria were formulated:
assure completeness of data
obtain a balance of information stored
allow intuitive operation
facilitate optimal user-computer interaction (e.g., effective screen layout, command structure,
and command execution)
permit efficient, useful, and "neat" reporting
facilitate efficient searches
facilitate efficient, multilocation updating of database content
realize efficient internal data storage in terms of computer core memory use and mass storage
facilitate fast operation (e.g., efficient CPU-mass storage device interaction)
allow portability within the hardware-software environment in which the database is developed
The design criteria for the model referral database MARS are discussed in detail in van der Heijde and
Williams (1989).
1.2.2 Database Management
Computer database management procedures emphasize data integrity and security, whether for
referral information or actual data sets. This is accomplished by developing and enforcing strict data
processing procedures that include authorization rules specifying that certain tasks be performed only by
a specified group of users. External users, for example, are not allowed to write, modify, or delete data from
the master database. Another important procedure requires routine data backup, thus allowing recovery
of the database files in the event that their content is corrupted, destroyed, or lost.
At the IGWMC, the referral databases are backed up automatically when their contents are updated.
In addition, the master database is backed up daily as part of institutional computer network backup
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procedures. The daily backups are stored for at least one week, while once a week a backup is made to
be stored for at least a month, etc.
To prevent program alteration, additional measures have been taken, including separation of program
source codes from the user-accessible environment, using only executable images of the software. In
addition, the operational software (both database management software and application programs) may be
reloaded from backup in the event of data corruption.
As the MARS referral database might be distributed off-site, complete with search and report-
generating software, procedures have been adopted to prevent data corruption off-site while maintaining the
integrity of database content. To protect this content, only compiled versions of the search and report-
generating software will be widely distributed, and database users will be provided periodically with updated
data files and application programs to replace their previous versions.
1.2.3 Identification and Annotation of Models
The IGWMC staff continuously collects and analyzes information on models related to subsurface flow
and transport phenomena. The initial information may come from open literature or from presentations and
discussions at conferences, workshops, and other meetings, or may be obtained directly from researchers.
Once a model of interest is located, additional information is collected from the research team that
developed the model, and from pertinent literature, to enable the Center's staff to include the model in the
MARS database. In selecting a model for inclusion in the referral database, special attention is given to the
importance of the model with respect to the kind of questions raised in model-based problem solving, and
to the development status of the model (e.g., research instrument or deliverable versus generally applicable,
well-tested and documented routine tool).
To assure consistency in the evaluation of the model information and in the data entered in the referral
database, a standardized form, the MARS data entry form, has been designed (van der Heijde and Williams
1989). A complete data set annotation includes comments made by the original development team and the
IGWMC staff, as well as bibliographic references regarding its development, theoretical foundation, updating,
and use. After detailed evaluation of the model documentation by the Center's staff, the data is entered into
MARS.
To ensure that the model description is correct and complete, a full report of the stored information
is verified with the model author or custodian, if identified.
Once all the information describing a model is entered in the referral database, the information is
checked for completeness and data entry errors.
Evaluation and verification of the information contained in the databases is a continuing process. In
order to fulfill the growing and changing information needs of users, comprehensive and flexible procedures
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for maintaining, updating, and expanding the databases have been adopted. Every few years the database
structure (programs and record structure) and contents are reviewed and revised.
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2. FLOW MODELS FOR POROUS MEDIA
Ground-water flow models simulate the movement of one or more fluids in porous or fractured rock
systems. One fluid is always water and the other may be an immiscible liquid such as a nonaqueous phase
liquid (NAPL). Most existing ground-water models consider only the flow of water in saturated or variably
saturated porous systems. Increasingly, research is concerned with multiphase flow of immiscible liquids
and water and with flow and transport in fractured media.
The mathematical model for ground-water flow is derived by applying principles of mass conservation
(resulting in the continuity equation) and conservation of momentum (resulting in the equation of motion;
Bear 1972, 1979). The equation of motion generally applicable in ground-water flow is Darcy's linear law
for laminar flow, which originated in the mid-nineteenth century as an empirical relationship. Later, a
mechanistic approach related this equation to the basic laws of fluid dynamics (Bear 1972). Some models
use a nonlinear equation of motion to describe flow around well bores in large fissures and in very low
permeable rocks (non-Darcian flow; Hannoura and Barends 1981, Huyakorn and Pinder 1983).
In order to solve the transient flow equation, both initial and boundary conditions are necessary
(Franke ef a/. 1984). Initial conditions for saturated flow systems consist of given values for the piezometric
head throughout the model domain. Initial conditions for variably saturated flow models are usually
expressed in terms of pressure head. For most models, inclusion of initial conditions is only needed when
transient simulations are performed. Boundary conditions for flow simulation may be any of three types:
specified head (Dirichlet or first type), specified flux (Neumann type or second type), and head-dependent
flux (Cauchy, mixed or third type) conditions. Boundary conditions are specified on the periphery of the
modeled domain, either at the border of the modeled area or at locations within the system where system
responses are fixed (e.g., connections with aquifer penetrating surface water bodies, or fluxes in/out of the
system such as through wells).
Models exist for simulating flow under saturated or partially saturated (i.e., unsaturated) conditions.
Models designed for saturated systems are not able to deal with unsaturated systems. Most of the models
designed for partially saturated systems can handle variable saturation conditions, sometimes over a wide
range from saturated or nearly-saturated to highly unsaturated conditions. The latter type of models use
a single set of equations, generally based on the Richards equation or a variant of it (DeJong 1981, El-Kadi
1983). Models that have separate formulations for simulation of flow in the saturated zone and unsaturated
zone are sometimes called coupled saturated-unsaturated zone models. Complex liquid wastes often
consist of multiple miscible and immiscible chemical components of varying density and viscosity. Saltwater
intrusion is another density-driven flow phenomenon that impairs parts of many coastal aquifers and,
increasingly, deep continental freshwater aquifers. An evaluation of methods for analysis of saltwater
intrusion is presented in Jousma ef a/. (1988). An overview of existing models for the latter type of use is
given by van der Heijde and Beljin (1985).
IGWMC has compiled a comprehensive descriptive listing of models that address saturated,
unsaturated, and multiphase flow. Appendix A of this report covers saturated flow models; Appendix B
covers models for variably saturated flow; multiphase flow models are listed in Appendix I. The listings have
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been compiled from the Center's MARS model referral database, and have been limited to those models that
are documented and available for third-party use.
2.1. MATHEMATICAL FORMULATION FOR SATURATED FLOW
The flow of a fluid through a saturated porous medium can be derived by combining the mass
conservation principle with Darcy's law resulting in (Bear 1979):
V • (KVh) - W = S, — (1)
in which h is the hydraulic head, t is time, K is the hydraulic conductivity tensor, Vf is the source/sink term
expressed as a volume flow rate per unit volume with positive sign for outflow and negative for inflow, and
S, is the specific storage that is defined as
S, = Pg(a + A?p) . (2)
where p , a are the fluid density and compressibility, respectively, n, p are the aquifer porosity, and
compressibility, respectively, and g is the gravitional acceleration.
Equation (1) can be written in a matrix form as
- ,
dx, ( " dxj) ' dt v '
where x, are the spatial coordinates, f is time, h=h(x,, t) is the hydraulic head, Kfisthe hydraulic conductivity
tensor. An overview of saturated flow models is presented in Appendix A.
2.2. MATHEMATICAL FORMULATION FOR UNSATURATED FLOW
Because air and water are immiscible fluids, when they coexist a discontinuity takes place between
the two phases. The difference in pressure between the two fluids, called capillary pressure (Pc ), is a
measure of the tendency of the partially saturated medium to suck in water or to repel air. The negative
value of the capillary pressure is called suction or tension. The capillary pressure head ($) is defined by
(DeJong 1981):
t - -^ (4)
99
The hydraulic head is given by
h = 2 - i|r (5)
in which z is elevation above an arbitrary datum.
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The governing equation for unsaturated flow is derived by combining the mass balance principle with
Darcy's law, ignoring compressibility of matrix, fluid, and air effects. The resulting equation, known as
Richards' equation, is (DeJong 1981, El-Kadi 1983)
V-(/CV/7) = F-|J (6)
where K = K (6) is the hydraulic conductivity, Q is volumetric water content, h is total head, t is time, and
F is moisture capacity defined as
F - 42- - - — (7)
h~ dh d* ()
The mathematical formulation and solution of the flow problem in the unsaturated zone require
describing the hydraulic properties of soil, preferably in functional forms. The soil-water characteristic
functions, t(0) and K(6), in which 0 is the volumetric water content, is included in these properties.
Hysteresis usually prevails in the relationship f(0), i.e., a different wetting and drying curve. Soil air
entrapment causes separation of the boundary drying and wetting curves at zero pressure. In fine-grained
soils, subsidence or shrinking may cause the same effects. In general, simulation under hysteresis is difficult
due to the existence of an infinite number of scanning, drying, and wetting curves, depending on the
wetting-drying history of the soil. Examples of the generalized algebraic equations representing the
moisture-characteristic curve with no hysteresis are given by Brooks and Corey (1964), Gardner (1958),
Haverkampefa/. (1977), and van Genuchten (1978). An overview of variably saturated flow models is given
in Appendix B.
2.3. MULTIPHASE FLOW
Fluids that migrate in the subsurface environment can be grouped with regard to their migration
behavior as either miscible (mixes) with water or immiscible (does not mix) with water (Morel-Seytoux 1973,
Parker ef a/. 1987). Miscible fluids form a single phase, while immiscible fluids form two or more fluid
phases (a fluid is either a liquid or a gas). Such a grouping of fluids is essential for discussion purposes
because the movement of two or more immiscible fluids is distinctly different from the simultaneous
movement of miscible fluids. The flow of immiscible fluids gives rise to two-phase or multiphase flow and
transport; miscible fluids give rise to single-phase flow and transport. The following discussion is based
primarily on Kincaid and Mitchell (1986).
Migration patterns associated with immiscible fluids introduced at the soil surface (e.g., as a chemical
spill) are schematically described by Schwille (1984). The extent and character of migration depends on
the chemical characteristics, the source volume, the area covered by the source, the infiltration rate, and
the retention capacity of the porous medium. Retention capacity is a measure of the volume of immiscible
liquid or nonaqueous-phase liquid (NAPL) that can be held in the porous medium without appreciable
movement. This volume is analogous to the volume of water prevented by the capillary force from draining
because of the gravity force.
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When the retention of the partially saturated soil column is not exceeded, the bulk of the liquid
chemical contaminant will be retained in the soil column. Migration of the contaminant away from the spill
site may occur as a result of its dissolution in water; it may also move in the gas phase. Contaminated soil
water arriving at the water table will be carried down-gradient in the unconfined aquifer and in the capillary
fringe. Figure 1 shows the ability of heterogeneous sediments within the partially saturated zone to laterally
spread or broaden the contaminant plume with increasing depth. To estimate the retention capacity of the
partially saturated soil column, the soil profile and moisture content must be known.
Ground Surface
Chemical
Vapor Phase
Partially Saturated Zone
Figure 1.
Schematic diagram of a chemical spill of a volume less than the retention
capacity of the partially saturated soil profile (from Schwille 1984)
When the bulk volume of the chemical entering the soil exceeds the retention capacity of the partially
saturated soil profile, the chemical will reach the water table in its liquid phase. Chemicals that are less
dense than and immiscible in water (Light Nonaqueous Phase Liquids, LNAPLs) will remain in the capillary
fringe of the partially saturated zone and near the water table in the saturated zone, as indicated in Figure
2. Examples of this type of pollutant are gasoline, jet fuel, and oil. Immediately beneath the spill, chemicals
can be forced below the water table level and into the saturated zone by the pressure of the overlying liquid
chemical mound (comparable to ground-water mounding in a phreatic aquifer resulting from recharge)
replacing the water present. As the plume migrates down-gradient, the overlying pressure decreases and
buoyant forces bring the lighter-than-water chemical up to the water table. The contamination will spread
as a distinct liquid chemical phase at the water table, and if the chemical's solubility allows, partially as a
dissolved constituent in the ground water. If the contaminant is volatile, it could also spread as chemical
vapor phase. It should be noted that some fraction of the chemical will be held in the porous medium by
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the retention capacity mechanism. Release of this fraction, as a dissolved constituent in soil water and
ground water, will be a long-term process.
Ground Surface
I
Chemical
Vapor Phase :
J I
Infiltration Rate
Partially Saturated Zone
Chemical
Spill
Capillary Fringe
Water Table-'
sSSSSft¥iS5¥Chemical Dissolved
^HSSg:;:;: In Water SwSS
Saturated Zone
Impermeable Medium
Figure 2. Schematic diagram of a lighter-than-water chemical spill of a volume greater than the retention
capacity of the soil (from Schwille 1984)
As a substantial part of bulk volume of a heavier-than-water immiscible liquid (e.g., TCE) reaches the
water table, the chemical will continue to move downward by displacing the ground water. These liquids are
called Dense Nonaqueous phase Liquids (DNAPLs). Depending on the physical/chemical properties of the
chemical with respect to the impermeable formation, the chemical may continue its downward migration or
form a mound above the impermeable bottom of the aquifer. Chemicals lying on the aquifer bottom will
migrate by following the relief of the bedrock or may enter the fractures in the bedrock. These various
aspects of the migration of the heavier-than-water chemical are shown in Figure 3.
As occurred in the partially saturated zone, heterogeneity within the saturated zone will cause the
contaminant to spread laterally as it migrates vertically. Note that the slope of the bottom topography (i.e.,
relief of the bedrock) may not coincide with the ground-water gradient; the chemical is driven by its own
hydraulic gradient not the hydraulic gradient of the ground water, and, hence, the migration of the solvent
phase may actually be in a direction opposite to ground-water flow.
The existence of distinct fluid phases competing for the same pore space is governed by mass and
momentum balance equations and data that uniquely specify the balance between the fluids in the soil
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environment. The wetting fluid is usually water; examples of a non-wetting fluid are mineral oil,
chlorohydrocarbons, and soil air (Parker et a/. 1987). Flow of each fluid is proportional to its potential
gradient, the permeability of the medium, the fluid density and viscosity, and the portion of pore space (i.e.,
cross-sectional area) that the fluid occupies.
Ground Surface
t I
Infiltration Rate
Chemical
Spill
Chemical
Vapor Phase
Partially Saturated Zone
Capillary Fringe
Water Table
Saturated Zone
Impermeable Medium
Figure 3. Schematic diagram of a heavier-than-water chemical spill of a volume greater than the retention
capacity of the soil (from Schwille 1984)
A fluid mass balance and Darcy's equation can be written for each of the fluids (Bear and Bachmat
1990). When the detailed-flow phenomena in each fluid phase are of interest, as is the case with two liquids,
the mass and momentum balance equations for each fluid should be solved. Consistent sets of saturation
and potential for each fluid are obtained from such an analysis. However, when flow phenomena for only
one of the two fluid phases are of interest, as is commonly the case with moisture movement in the partially
saturated zone, the saturation and potential of the fluid of interest should be solved. The saturation of the
second fluid can then be simply calculated given the porosity of the medium (i.e., given that it occupies the
remaining pore space).
The relative permeability of the wetting and non-wetting fluids depends strongly on the degree of
saturation (Dracos 1978, Parker et al. 1987). The curves describing ihe permeability of the fluids show the
nonlinear behavior of fluids in a partially saturated environment. Unique curves exist for different fluids and
media. In general, each fluid must reach a minimum saturation before it will flow. In the case of water and
air, the minimum saturation for water is called the irreducible saturation. For moisture movement in the
22
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vadose zone, soil physicists have found that irreducible saturation is actually a .function of the suction
pressure applied and the length of time one is willing to wait for the soil column to respond. Thus,
irreducible saturation may not necessarily be single-valued. The wetting or non-wetting fluid must exceed
its residual saturation before it will flow. Residual saturation is the measure of the ability of a soil to retain
moisture and consequently the bulk of a chemical spill.
One of the more complex migration patterns that may occur involves three phases (Kuppussamy ef
a/. 1987). Water and chemical would exist as liquid phases and soil air would exist as a gaseous phase.
The flow process is more complicated than the two-phase situation, although the same principles of mass
and momentum balance apply. The individual fluids are immobile over relatively large areas of the saturation
triangle, as shown in Figure 4; a relatively small central region exists over which all three phases are
simultaneously mobile.
Water
100%
100%
Figure 4. Funicular zones for three immiscible fluids
At low organic fluid saturations, a continuous organic phase may not exist and the organic fluid might
be present as isolated globules surrounded by water. Such continuity is an essential assumption in virtually
all existing models. In the current generation of models, discontinuity in a phase means that the relative
permeability of the fluid goes to zero and that the model predicts no flow (Parker ef a/. 1987). In reality,
however, migration of these isolated parcels of organic fluid can occur, resulting in a process termed "blob
flow." This process is well known in tertiary oil recovery where the aim is to mobilize such "blobs," using
injected surfactants and gases (e.g., Gardner and Ypma 1984). Existing mathematical models and codes
cannot handle transport by way of globule migration.
23
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2.3.1. Modeling Multiphase Flow
Models and codes for organic chemical migration are commonly categorized as (1) those for which
fluid physics of immiscible organic liquids are emphasized, and (2) those for which organics appear as
miscible constituents in which chemical/microbiological reactions for dilute levels of contamination are
emphasized. Existing models and codes can be used to model selected phases to the extent that vapor
phase exchange and transport, geochemical reactions, and microbiological degradation can be incorporated
in existing codes (i.e., insofar as the mathematical equations are unchanged by the addition of these
processes and reactions). These models are based on the assumption that for each phase continuous flow
paths exist throughout the porous medium (Streile and Simmons 1986). A simplified version of such an
approach is presented by Dracos (1978). The proposed model consists of vertical one-dimensional flow in
the unsaturated zone through a column of radius R, under the source (Figure 5) and a two-dimensional
horizontal model for the low density liquid atop the water table. For the miscible component in the plume
a common two-dimensional solute transport model is used, taking the source term from the one-dimensional
vertical column model. That it is not easy to make simplified modeling approaches work successfully for
real-world phenomena is demonstrated by the Bartz and Kass experiment (Figure 6) in which the bulk oil
continues to advance slowly after 120 days, but the outmost boundary of detectable solutes is retreating,
resulting in a 120-day contour being located outside the 360-day contour (Dracos 1978).
Experimental models for more complex systems, documented recently, include finite-element
formulations by Abriola and Pinder (1985a, 1985b) and Kuppusamy ef a/. (1987) and a finite-difference
formulation by Faust (1985).
Models available for simulating NAPL contamination can be grouped into (1) sharp interface models,
(2) capillarity models, and (3) interphase partitioning models. In the first category, it is assumed that sharp
interfaces exist between various fluid phases. These models develop analytical and semi-analytical
expressions for time versus infiltration and subsequent spreading of hydrocarbons. The second category
of models solve numerically the partial differential equation describing the flow of the hydrocarbon coupled
with functional relationships describing saturation and permeability. The third category includes the
interphase partitioning of organics between the nonaqueous and water or vapor phases.
NAPL transport has been studied experimentally and modeled by a number of researchers; recent
reviews have been introduced by Mackayefa/. (1985), Abriola (1988), Parker (1989), and Mercer and Cohen
(1990). Relevant studies include the work by van Dam (1967), Schwille (1971a,b,c, 1981, 1988), and
Albertsen et a/. (1986). These publications dealt mainly with analyzing the processes involved in the
infiltration and subsequent spreading of light or heavy hydrocarbons. Modeling efforts include the work by
van Dam (1967), Mull (1969, 1971, 1978), Dracos (1978), and Schiegg (1977), all of whom assumed sharp
interfaces between various fluid phases. The studies by Mull, Dracos, and Schiegg developed analytical and
semi-analytical expressions for time versus both infiltration and subsequent spreading of light hydrocarbons.
El-Kadi (1991) adopted some of these formulations and examined the accuracy of the infiltration phase by
comparing the results to those obtained by the numerical model of Kaluarachchi and Parker (1989) which
included capillarity effects. As expected, the model is most accurate for NAPL infiltration into soil with a
deep water table where pressure changes in soil-water are minimum. Corapcioglu and Hossain (1986) also
24
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Ground surface
Groundwater flow
Water table
Figure 5. Schematized vertical infiltration and horizontal spreading of the bulk of a low density hydrocarbon
atop the water table (after Dracos 1978).
25
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adopted the sharp interface assumption to estimate infiltration of hydrocarbons and solved numerically a
two-dimensional equation describing the dissolved phase.
360
Oil bulk zone
Zone of dissolved components
m®&
^^^^^^^^^^^^^^^^^^•^^^^low direction
Oil infiltration
source
ow.c
ire<
?.*!
„ 120 days
;;N
\-
-f-
0 10
-i
50 m
Figure 6. Oil bulk zone and spreading of dissolved components in ground water from a field experiment
by Bartz and Kass (after Dracos 1978)
Models that include capillarity effects have been also introduced to reduce the limitations of the sharp
interface approach. This category includes the work of Arthur D. Little (1983), Faust (1985), Osborne and
Sykes (1986), Kuppusamy et a/. (1987), and Kaluarachchi and Parker (1988). These models solve
numerically a partial differential equation describing the flow of the hydrocarbon (i.e., mass balance
combined with Darcy's law) coupled with functional relationships describing saturation and permeability.
A more refined category of NAPL models includes the interphase partitioning of organics between the
nonaqueous and water or vapor phases (Corapcioglu and Baehr 1987, Baehr and Corapcioglu 1987, Baehr
1987, Allan 1986, and Abriola and Finder 1985a,b,c). The formulations adopted usually result in a system
of highly nonlinear partial differential equations that require an iterative numerical technique.
In the sharp interface approach, the migration process is divided into four phases: (1) infiltration, (2)
intrusion and initial spreading, (3) final spreading, and (4) dissolved material migration (Figure 2). As Dracos
(1978) indicated, such division is justified due to the difference in the time scale of each phase of the
transport. The infiltration phase is fast and can be measured in hours. The early spreading, which depends
26
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on pressure buildup, is one order of magnitude slower and thus can be measured in days. The last two
phases are much slower and can be measured in months or even years. The sharp interface approach
develops a time-distance profile for various stages from Darcy's law. The following assumptions are
included in the formulation:
1. The NAPL gas phase is assumed to be at constant pressure, so only the liquid phase is
modeled. Such an assumption is not generally valid due to the volatile nature of NAPL.
However, ignoring the gas movement is likely to produce a more conservative estimate
to travel times.
2. A sharp transition between NAPL-saturated and dry conditions is assumed; hence, the
saturation-capillary relation is idealized as a rectangle, indicating that the pore system is
either dry or saturated with the fluid. This assumption is generally acceptable for coarser
material.
3. Only air is displaced by the infiltrating NAPL in the unsaturated zone. Air is also assumed
to move freely under constant pressure, and water to be immobile. These conditions are
generally acceptable in soils near dry conditions.
4. The displacement of fluids is assumed as piston flow; one fluid replaces the other, and
hence only one mobile fluid exists in a given location. This type of flow is expected to be
most accurate for coarse-textured soils or in situations where gravity or pressure
predominates over capillarity.
5. Lateral spreading is ignored, i.e., the flow is assumed to be strictly vertical. Such an
assumption is acceptable if the spill area is relatively large.
6. The water table is assumed to be too deep to have an influence on NAPL transport. This
could be a serious limitation in some cases due to the large pressure gradient in water,
which may affect NAPL movement.
7. Compressibility effects of matrix and fluids are ignored, which is a common assumption
in the general treatment of transport in the unsaturated zone.
Interphase flow and transport models include the interphase partitioning of organics between the
nonaqueous and water or vapor phases. The equations are derived from mass conservation principles by
the application of volume-averaging techniques and the incorporation of various constitutive relations and
approximations (Abriola and Pinder I985a). Effects of matrix and fluid compressibilities, gravity, phase
composition, interphase mass exchange, capillarity, diffusion, and dispersion are considered. The
assumption of equilibrium leads to some simplification in the system of governing equations. Although this
approach is more realistic in representing the physical phenomena of flow and transport in NAPL-air-water
systems, its application is hindered by difficulties in solutions and by the data requirement. The governing
equations are not given here because the system of governing equations is very involved.
27
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A more detailed discussion of the mathematical formulations encountered in multiphase flow modeling
is given in an earlier report by El-Kadi etal. (1991). Appendix I provides an overview of multiphase models.
28
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3. TRANSPORT MODELS FOR POROUS MEDIA
3.1. SOLUTE TRANSPORT
The ground-water transport of dissolved chemicals and biota (e.g., bacteria and viruses) is directly
related to the flow of water in the subsurface. Many of the constituents occurring in ground-water can
interact physically and chemically with the solid phase (soil particles), and with various dissolved chemicals.
As a consequence, their displacement is both a function of mechanical transport processes such as
advection and dispersion, and of physicochemical interactions such as adsorption/desorption, ion-exchange,
dissolution/precipitation, reduction/oxidation, complexation, and radioactive decay (Luckner and
Schestakow 1991). Biotransformations taking place during transport can alter the composition of the
ground-water significantly (Ward ef a/. 1985).
In modeling the transport of dissolved chemicals, the principle of mass conservation is applied to each
of the chemical constituents of interest. The resulting equations include physical and chemical interactions,
as between the dissolved constituents and the solid subsurface matrix, and among the various solutes
themselves (Konikowand Grove 1984, Reilly ef a/. 1987, Bear and Bachmat 1990, Luckner and Schestakow
1991). These equations might include the effects of biotic processes (Molz ef a/. 1986, Borden and Bedient
1986, Srinivasan and Mercer 1988). To complete the mathematical formulation of a solute transport
problem, equations are added describing ground-water flow and chemical interactions, as between the
dissolved constituents and the solid subsurface matrix, and among the various solutes themselves. In some
cases equations of state are added to describe the influence of temperature variations and the changing
concentrations on the fluid flow through the effect of these variations on density and viscosity.
Under certain conditions such as low concentrations of contaminants and negligible difference in
specific weight between contaminant and the resident water, changes in concentrations do not affect the
flow pattern (homogeneous fluid). In such cases a mass transport model can be considered as containing
two submodels, a flow submodel and a quality submodel. The flow model computes the piezometric heads.
The quality submodel then uses the head data to generate velocities for advective displacement of the
contaminant and spreading through dispersion. Transformations by chemical and microbial reactions may
also be included. The final results are computed concentrations and solute mass balances. In cases of high
contaminant concentrations in waste water or saline water, changes in concentrations affect the flow
patterns through changes in density and viscosity, which affect the movement and spreading of the
contaminant. To solve such problems through modeling, simultaneous solution of flow and solute transport
equations or iterative solution between the flow and quality submodels is required (Huyakorn and Pinder
1983, Voss 1984, Kipp 1987).
Mass transport models which handle both advective and dispersive transport processes are
sometimes called miscible transport models. Models that only simulate advective and dispersive
displacements are called conservative models. Nonconservative models simulate both displacements and
transformations of contaminants. Nonconservative solute transport models are often based on the
assumption that the reactions proceed instantaneously to equilibrium. In general, the reaction rates depend
29
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on the residence time for the contaminant. Recently, various researchers have become interested in the
kinetic approach that incorporates chemical reactions in transport models (e.g., Brusseau et al. 1989,
Valocchi 1989, Sardin ef al. 1991).
The inclusion of geochemistry in solute transport models has focused on single reaction such as ion-
exchange or sorption for a small number of reacting solutes. Because multicomponent solutions are
involved in most contamination cases, there is a need for models that incorporate the significant chemical
interactions and processes that influence the transport and fate of the contaminating chemicals. There are
two approaches for modeling multicomponent solutions. In the first approach, the interaction chemistry may
be posed independently of the mass transport equations. The most widely used form of this approach is the
coupling of the transport equation with an equilibrium or kinetic phase exchange reaction such as the
Langmuir or Freundlich isotherm (Jennings et al. 1982). The second approach is to insert all of the
interaction chemistry directly into the transport equations (Jennings 1987).
Several difficulties impair both the credibility and the efficient use of mass transport models. One such
difficulty is "numerical dispersion" in which the actual physical dispersion mechanism of the contaminant
transport cannot be distinguished from the front-smearing effects of the computational scheme (Huyakorn
and Finder 1983). Another numerical problem influencing the results of solute transport modeling takes the
form of spatial oscillations (overshoot and undershoot) near a concentration front, especially for advection-
dominated transport, sometimes resulting in negative concentrations. A problem inherent to all numerical
techniques, although of a different order of magnitude, is numerical inaccuracy. Numerical problems can
often be mitigated by grid refinement or, in some cases, selection of an alternative method (Huyakorn and
Pinder 1983). For particle-in-a-cell methods (e.g., random walk method and method of characteristics),
higher accuracies can be obtained by increasing the number of particles in the system (Uffink 1983,
Kinzelbach 1986).
Another issue is model dimensionality. Although a pollution problem is typically three-dimensional,
vertical averaging is frequently used, resulting in the utilization of a two-dimensional, horizontal mass
transport model that is generally connected with a hydraulic flow model. Such models tend to
underestimate peak values and thus may fail to predict dangerous concentration levels and critical arrival
times of pollutants in wells that become polluted by surface or near-surface sources.
It should be noted that multi-phase petroleum reservoir models do not appear to be readily applicable
to organic transport analyses. These codes address only fluid flow phenomena and neglect entirely
transport and attenuation phenomena. Petroleum reservoir simulators are useful in regard to the theory and
numerical methods embodied for simulating multiphase, immiscible-fluid flow.
Appendix C presents an overview of available solute transport models.
30
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3.1.1. Advection-Dispersion Equation
Processes that control the migration of solute include advection, hydrodynamic dispersion,
geochemical and biochemical reactions and radioactive decay.
In the case of a conservative solute, no reactions occur between the solute and the solid phase. The
rate of transport is equal to the seepage velocity. If the transport of solute is due only to advection, a sharp
interface will separate the flow domain that contains the solute and the native ground-water. However, this
interface does not remain sharp because hydrodynamic dispersion causes the solute spreading over a
greater volume of aquifer than would be predicted by advection alone. This means that the travel time from
the source to the point of observation for part of a pollutant release will be less than derived from
calculations focussed on the center of the plume or based on a sharp front approach.
Advection-
Advection is the solute movement with the bulk flow of the fluid (water). Estimation of advection is
based on fluid flow characteristics, flow paths, and velocity. Numerical models are often used as a
substitute for field measurements to identify the flow field.
Dispersion-
Dispersion is considered to be caused by both microscopic and macroscopic effects (Dagan 1986).
However, most studies of flow through porous media are conducted on a macroscopic scale where Darcy's
law is valid. Hydrodynamic dispersion refers to the spreading of a solute at the macroscopic (Darcy) level
by the combined action of mechanical dispersion and molecular diffusion (Bear 1972, 1979; Bear and
Bachmat 1990; Battacharya and Gupta 1990; Moltyaner 1990). Mechanical dispersion is caused by the
changes in the magnitude and direction of velocity across any pore cross-section at the microscopic level.
Pores differ in size and shape, also causing variation in the maximum velocity within individual pores, in
addition to velocity fluctuations in space with respect to the mean direction of flow. This results in a
complex spatial distribution of the flow velocity. Molecular diffusion results from variation of solute
concentration within the liquid phase and causes the solute to move from regions of higher concentration
to regions of lower concentration.
In general, flux, Qc, due to mechanical dispersion is estimated by analogy to Pick's law, i.e., flux is
proportional to concentration gradient (Bear 1979). Combining expressions of both the diffusion and
mechanical dispersion result in the equation
Qc = -D'VC (8)
in which D1 is the coefficient of hydrodynamic dispersion. D' is estimated as the sum of the coefficients
of mechanical dispersion, D, and molecular diffusion, Dm. D is a tensor usually having longitudinal and
transverse components. Dm is expressed generally as a function of the molecular diffusion coefficient of a
chemical species in pure water and a tortuosity factor accounting for the pore system and the degree of
saturation (Bresler and Dagan 1981, Gupta and Battacharya 1986), namely,
(9)
31
-------
in which TJ, is the tortuosity factor, 6 is volumetric water content and D'm is the diffusion coefficient in
pure water. One model for TJ, is
(10)
where n is porosity. Equation (10) is similar to that concerning air diffusion, as proposed by Millington and
Quirk (1961). Written in tensor form, the coefficient of hydrodynamic dispersion can be expressed as
D',j= D,r Dm6l/ (11)
where Df is the coefficient of mechanical dispersion, Dm is the coefficient of molecular diffusion, and 6/y is
the unit tensor.
The contribution of molecular diffusion to hydrodynamic dispersion is small when compared to
mechanical dispersion and for any practical purpose may be neglected. However, its effects cannot be
neglected for underground injection of hazardous wastes where the injection rates are in the order of
centimeters per year for very fine soils (e.g., clays).
The coefficient of mechanical dispersion is usually expressed as a function of the velocity of ground-
water and to the fourth order tensor,
-------
Dispersivity is influenced by vertical and horizontal permeability, permeability variations, and degree
of stratification (Guven etal. 1984, Black and Freyberg 1987; Moltyaner 1990; Molz etal. 1990). Because
large solute plumes encounter more permeability variations than small plumes, dispersivity tends to increase
and approach some maximum asymptotic value (Gelhar ef a/. 1979). The difference between dispersivity
values measured in the laboratory and evaluated in the field may be attributed to the effects of heterogeneity
and anisotropy (Pickens and Grisak 1981a,b, Neuman etal. 1987). The values obtained from tracer tests
are equivalent dispersivities that represent dispersion between the measuring point and the injection point
(Anderson 1984).
Because of the difficulties in measuring dispersivity, both longitudinal and lateral dispersivities are
often determined during calibration of the model. The common assumption is that the medium is isotropic
with respect to dispersivity, which implies isotropy with respect to hydraulic conductivity. In practice, this
is acceptable because most models used for solving field problems are two-dimensional with vertically
averaged hydraulic properties and because generally the horizontal hydraulic conductivity is much larger
than the vertical hydraulic conductivity. It should be noted that increasingly stochastic formulations are used
to describe the dispersion process (Gelhar 1986, Smith and Schwartz 1980, Uffink 1983, Dagan 1989,
Neuman etal. 1990).
The partial differential equation for solute transport, including dispersion, convection, and a
sink/source term may be expressed as (e.g., Anderson 1984)
. 3C
n at (15)
[dispersion] [convection] [sinkfsource]
where C is concentration of solute, C1 concentration of solute in the source or sink fluid, D^ coefficient of
dispersion, and v, seepage or pore velocity. The seepage velocity is calculated as
v, = - J& |* = - 9. (16)
' n dXj n v '
The hydraulic head, h, is obtained by solving equation (1) or (6).
Adsorption--
Chemicals may partition between volatilized, adsorbed, and dissolved phases. An adsorbed chemical
will migrate away from the source of pollution at a different rate than a nonsorbed chemical.
If adsorption/desorption between solid and liquid phase is considered, equilibrium-controlled equation
(15) may be expressed as (Konikow and Grove 1984):
__ +
dx, dx, dx, n dt( n
where ph is the dry bulk density of the solid and S is the concentration of solute adsorbed on the solid
surface.
33
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The relationship between adsorbed concentration (S) and liquid concentration at equilibrium (C) is
called the adsorption isotherm:
S = S(C) (18)
This relationship is obtained in laboratory experiments where the temperature is kept constant and the
reactions are allowed to reach equilibrium. Several types of models for adsorption or ion exchange
isotherms exist. Most frequently used isotherms are
Linear S = /C,C + Kz (19)
K C
Langmuir S = - — 1— - (20)
I + AjC/
Freundlich S = K,CK* (21)
where K, and K2 are empirically derived constants. The simplest isotherm is given as
5 = KdC (22)
where Kd is the distribution coefficient:
_ mass of solute on the solid phase per unit of solid phase
" concentration of solute in solution
Distribution coefficients for reactive nonconservative solutes range from values near zero to 103 ml/g or
greater (Mercer et al. 1982b). All adsorption models represent reversible adsorption reactions. Generally
two or more transport equations have to be solved for multi-ion transport problems.
By incorporating equation (22) into equation (17), the advection-dispersion equation takes the form:
"
dx, dx,) dx, n dt
where fl, the retardation coefficient, is given by
v '
R = 1 + - Kd (24)
n
As a result of sorption, solute transport is retarded with respect to transport by advection and
dispersion alone. Sorption reduces the apparent migration velocity of the center of a plume or a solute
front (vt) relative to the average ground-water flow velocity (vgw) , or
/? » -!jK>1 (25)
V,
For Kd values that are orders of magnitude larger than 1 , the solute is essentially immobile. Sorption
capacity of geologic deposits is generally given in this order: gravel < sands < silts < clays < organic
material (Mercer ef al. 1982b). If no sorption occurs, the retardation factor is equal to 1.
Transformation/Degradation--
Transformation processes determine the fate and persistence of chemicals in the environment. The
key processes include biotransformation, hydrolysis, and oxidation/reduction. The transformation processes
34
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are generally lumped as a reaction term in the solute transport equation. Reactions are usually represented
by an effective rate coefficient which depends on a number of variables such as organic matter content,
water content, and temperature. For simplification purposes, however, a first-order constant rate is usually
employed in the analysis. For decay it is written as (Konikow and Grove 1984)
= - v-C (26)
9t
in which p is the rate constant.
The solute (tracer) may undergo radioactive or biological decay
= - AC (27)
where A. is the decay constant and can be calculated if the half-life of the tracer (t1/4) is known:
X = M . (28)
'1/2
Including decay and retardation and assuming decay rates are the same for sorbed and mobile
species, equation (23) becomes
_.n _ J_ - _ _ _ XRC __ R
dx " dx\ dx * /; n dt v
Biodegradation-
Biodegradation in ground-water refers to chemical changes in solute or substrate due to microbial
activity. Reactions can occur in the presence of oxygen (aerobic) or in its absence (anaerobic). Research
related to biodegradation include the work of Troutman etal. (1984), Borden etal. (1984, 1986), Borden and
Bedient (1987), and Barker and Patrick (1985). Modeling efforts include the work of Sykes et al. (1982),
Borden ef al. (1984), Borden and Bedient (1986), Bouwer and McCarty (1984), Molz ef al. (1986), and
Srinivasan and Mercer (1988).
Studies indicate that the number of electrons must be conserved in all biochemical reactions
(Srinivasan and Mercer 1988). In such reactions, a reduced product (called electron acceptor) exists
whenever a product has carbon atoms in a higher oxidized state due to the loss of electrons. For example,
in aerobic reactions oxygen is the electron acceptor and is reduced to water. In anaerobic systems N03
is the electron acceptor and is reduced to NO~2, NO2, or N2.
Modeling approaches can be divided roughly into: (1) an approach that uses the biofilm concept to
simulate the removal of organics by attached organisms (Molz ef al. 1986), and (2) an approach that
assumes that microbial population and growth kinetics have little effect on the contaminant distribution
(Borden ef al. 1984, Srinivasan and Mercer 1988). Both approaches apply Monod kinetics or a modified
form of them, to reduce the required number of equations.
35
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Application of the first approach results in a set of five coupled nonlinear equations that need to be
solved simultaneously to calculate (Molz et al. 1986): (1) concentration of substrate; (2) concentration of
oxygen; (3) substrate concentration within the colony; (4) oxygen concentration within the colony; and (5)
number of organism colonies per unit volume of aquifer. Three of the five equations are partial differential
equations and two are algebraic equations. Micro-colony kinetic parameters are needed for the analysis.
The authors applied their approach to a one-dimensional problem for illustration purposes and performed
a sensitivity analysis.
Application of the second approach by Borden and Bedient (1984) and Borden ef al. (1986) has
resulted in a two-dimensional model based on three partial differential equations describing contaminant
concentration, oxygen concentration, and concentration of microbes in the solution.
Volatilization-
Volatilization is defined as the loss of a chemical in vapor from soil, water and plant surfaces. This
process is controlled by the availability of vapor at the soil surface and the rate at which this vapor is carried
to the atmosphere. In addition to the saturated vapor pressure of the chemical under consideration, a
number of factors affect the actual volatilization rate from the soil surface, including soil and atmosphere
characteristics, and management practices. Interaction among these components is also an important
factor.
Generally, chemicals can partition into adsorbed, dissolved, and vapor phases. Under equilibrium
conditions, the vapor pressure of a solute above its aqueous solution, CG, is related linearly to the
concentration in solution, C, by Henry's law (Fetter 1993)
CG = KHC (30)
where KH is Henry's constant. A similar relationship was described earlier regarding partitioning into
adsorbed and dissolved chemicals.
Vapor movement from the soil to the atmosphere is usually modeled by applying Pick's Law of
diffusion (Hern et al. 1986). Chemical movement in gaseous form through soil is described by an extension
of the same law. The vapor flux is related to concentration gradient by
qv = - nz(a)DGVCQ
in which r\2 is a tortuosity factor and DQ is the dispersion coefficient in air. Millington and Quirk (1961)
defined r\z empirically, by
a 10/3
<32>
IT
in which a is air content and n is soil porosity. Equation (31) can be added to the genera! solute transport
equation as a sink term.
36
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Plant Processes--
Vegetation is an integral part of the terrestrial ecosystem. Chemicals applied to land surfaces may
be intercepted by plant leaves where volatilization, photolysis, or biodegradation occur in addition to
absorption by the plant. At a later time, chemicals initially intercepted may be washed off by rain or
irrigation water and contribute to solute transport in the soil. Plant roots also affect the transport phenomena
by uptaking the chemicals into the plant where they can accumulate in different parts of the plant.
Chemicals may move to the leaves where they are subject to transformation and degradation processes.
The remaining chemicals may return to the soil following plant death or leaf fall.
Additional modeling difficulties result from the dynamic nature of plants, caused by changes in their
condition from the time of planting until harvesting. Also, stem and root penetration can influence the
transport phenomena by changing the hydraulic properties of soil.
Plant models have been introduced by plant and soil scientists (see Thornley 1976, Tillotson et al.
1980, Campbell 1985). Molz (1981) compiled a list of extraction functions used by various researchers to
represent water uptake by plant roots. An exponential depth function adequately describes the extraction
patterns for a number of crops under relatively stable conditions, such as a fully developed crop under high
frequency irrigation (Feddes ef al. 1974). Models including relationships for plant uptake of dissolved
chemicals are often based on the rates established for water uptake.
3.2. HEAT TRANSPORT
Analysis of heat transport in soils and ground-water aquifers is an important area of research and has
many practical applications. Heat transport affects other transport processes directly and indirectly, e.g.,
contaminant transport. Conversely, heat transport might be affected significantly by other physical and
chemical processes. Overlooking such interactive effects may lead to unacceptable errors. Direct effects
on pollutant transport are attributed to, for example, changes in the soil/ground-water flow field due to
freezing/thawing on the chemical transformation rates due to temperature changes. The indirect effects are
due to the fact that some parameters are to a certain extent heat dependent (e.g., hydraulic conductivity).
Major research activities of heat transport processes took place in the 1970's and early 1980's,
stimulated by the public interest in high temperature geothermal systems for energy production.
Accordingly, attention has been paid to models for simulation of complex systems such as water-steam-rock
(Grant ef al. 1982). Further applications of research relevant to heat transport in the subsurface include
aquifer thermal energy storage (Mercer ef al. 1982a). There, warm waste water from cooling systems is
injected into a confined aquifer during the warm season. During the cold season, warm water is recovered
and utilized for heating purposes. The resulting cold water is reinjected far enough from the recovery well
to prevent accelerating the cooling process of the warm water. An efficiency of heat recovery of up to 60%
has been reported in the literature (Molz ef al. 1978).
Another area of growing interest related to heat transport concerns modeling flow and solute transport
under freezing/thawing soil conditions. Difficulties in mathematical formulation, in solution approaches, and
37
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in parameter estimation are currently major hurdles toward the development of practical solutions to this
complex problem.
Mathematical formulation of the general heat transport problem in the subsurface involves a coupled
system of equations describing the flow of water and heat. The governing partial differential equations are
nonlinear, because some parameters are a function of at least one dependent variable (temperature)
interrelated by equation of state. In such a case, only numerical techniques might provide a solution. To
solve the general equations analytically, a simplified subset of the general equations is required, resulting
in separate, non-coupled solutions for flow and heat transport (Mercer ef al. 1982a). The analytical solutions
for flow assume isothermal conditions. The analytical solutions for heat transport assume a very simple and
known flow field.
Numerical methods used in heat transport models were reviewed by Finder (1979), Lunardini (1981), Mercer
et al. (1982a), and Huyakorn and Finder (1983); in more general terms, heat transport models were
described in Bachmat et al. (1978), van der Heijde ef al. (1985), and El-Kadi ef al. (1988).
This section reviews briefly the theory of flow of water and solute in the subsurface under
nonisothermal conditions. Details of the formulations may be found elsewhere (e.g., Lunardini 1981 and
Farouki 1986). A list of available models is provided in Appendix D.
3.2.1. Heat Transport Equation
Ground-water may appear as ice, liquid, or steam, interacting with an aquifer. The heat transport
equation is derived by applying the energy balance principles concerning the transport, storage, and external
sources/sinks of heat. Dependent variables in this equation may be temperature or enthalpy. In general,
a state of thermodynamic equilibrium is assumed, i.e., the temperature in different constituents (solids and
fluids) is equal within the representative elementary volume for which the equations are derived. The
processes that contribute to heat transport include conduction, convection, dispersion, radiation,
evaporation/condensation, and freezing/thawing. Heat conduction occurs in all soil constituents, i.e., solids,
water in different phases, and air. In air and vapor, heat conduction is caused by collision between
molecules that increases their mean kinetic energy as heat moves from warmer to cooler regions. In liquid
water, the same process occurs in addition to energy transfer by breaking and forming of hydrogen bonds,
In crystalline solids, e.g., quartz, increased atomic vibration at one end will cause the neighboring atoms in
the lattice to follow suit. Heat flux due to conduction is given by
(33)
in which T is temperature and K0 is the thermal conductivity of the porous medium (water plus solid),
defined as the rate which heat energy flows across a unit area of the soil due to a unit heat gradient in a
porous matrix (Bird 1960).
Free or forced heat convection contributes to heat transfer. Free convection develops due to the
existence of a temperature gradient resulting in density changes. On the other hand, forced convection is
38
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due to currents of fluids that move through pores of soils as a result of head gradients. For a fluid with
velocity vw the convective flux is given by
Qcn = vwPwC*T (34)
in which pw and C,,, are density and specific heat of the fluid, respectively.
Dispersion, sometimes referred to as lateral mixing or turbulent diffusion, is caused by mixing in the
pore system. Dispersive heat flux is given by
(35)
in which 5 is the heat dispersion coefficient
* = PIVJ (36)
where p is heat dispersivity analogous to solute dispersivity, field observations indicate in the same aquifer
that their magnitudes may differ (de Marsily 1986).
Radiation, usually an unimportant process in heat transport in soils, is the emission of heat from
bodies that have temperatures above absolute zero. Heat energy is emitted in the form of electromagnetic
waves and travels across a vacuum as well as gases, liquids, or solids. The flow of heat depends mainly
on the temperature of the radiating body, namely,
QR = oeA(T-T0)* (37)
which is known as the Stefan-Boltzmann law. In equation (37), A is the surface area, o is a constant,
and e the emissivity of the surface (0
-------
where Cs, C^ and Cf- are specific heat of solids, water, and ice, respectively, 6, is the total moisture
content, 6U is the unfrozen moisture content, and L is the latent heat of freezing water. The expression
in equation (39) is based on the assumption that the specific heat of unfrozen water is the same as that for
water under standard conditions (20°C, 0,1 MPa).
Ignoring air movement, the general heat transport equation can thus be derived by applying the mass
balance principal to yield
v-{Qc, + QD + Qon] = j-f {£ ie/Pcyr} + sh (40a)
or
vr + vwPcwr} = j-f {£ le^r} + sh (4ob)
in which Sh is a source/sink term that includes radiation, evaporation/condensation, or freezing/thawing
effects. The subscript/ in equation (40) refers to unfrozen water and ice (i.e., /= w for water and /=/ for ice).
Simplified versions of equation (40b) have been utilized in the analysis, especially in the absence of phase
change processes. For example, for a fully saturated aquifer, if heat conduction and density changes are
neglected, and if heat capacity was taken as constant, the equation becomes
* ^r)l = «*IF + s» (41)
in which a „ is the heat capacity of the aquifer.
3.3. VAPOR TRANSPORT
Soil Vacuum Extraction (SVE), or soil venting technology has recently received increasing attention
as a relatively inexpensive method for cleaning up hazardous waste sites contaminated with volatile organic
compounds (VOCs). This new technology is based on inducing an air flow through the soil, using a vacuum
pump or blower, hence stripping and volatilizing the volatile organics from the soil matrix into the air stream
(HMCRI 1991, Grower a/. 1985, NWWA 1991).
In addition to remediating soils via volatilization, soil vacuum extraction has the potential for enhancing
abiotic or biotic degradation of contaminants because it can circulate air or other gases such as ozone at
different depths.
In order to evaluate, utilize, and enhance the performance of soil vacuum extraction technology, it is
important to understand the physical, chemical, and biological processes that control the transport and fate
of volatile contaminants in the subsurface. These processes include multiphase flow (i.e., flow of air, water,
and organic compounds), diffusion, dissolution, volatilization, etc. Because of the complex nature of the
interactions among these processes, a need exists for laboratory and field studies in addition to
mathematical model studies.
40
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3.3.1. Phvsicochemical and Biological Processes
A number of studies have been documented as attempts to improve the understanding of the complex
physicochemical and biological processes involved in soil venting. The processes involved in gas migration
through the unsaturated zone are similar to those involved in contaminant transport in the subsurface.
Gases are transported in soil by convection due to a pressure gradient, by diffusion due to a concentration
gradient, and by compressibility and temperature effects. The governing equations describing contaminant
transport in ground-water are adapted for describing gas movement in soil; however, they are usually
formulated in terms of molar averaged quantities rather than mass averaged quantities (Mohsen ef a/. 1980,
Metcalfe and Farquhar 1987). Metcalfe (1982) provided additional terms to account for the dissolution of the
contaminant gas in the soil moisture and the movement of the dissolved phase of the gas due to downward-
percolating rainwater, but these terms have not been validated with field data.
Soil characteristics influence the sorption behavior of organic vapors and thus affect the efficiency of
vacuum extraction processes. As a result of using dry air for vacuum extraction, a dehydrated soil becomes
a powerful adsorbent for organic vapors and hence reduces the efficiency of vacuum extraction processes.
On the other hand, when water exists, it displaces the organic compound from the mineral surface and
decreases the soil air conductivity. Therefore, humidified air can be used in a way to optimize the SVE
processes and keep the soil permeability at a certain level (see Chiou and Shoup 1985).
3.3.2. Laboratory and Field Studies
Laboratory studies can provide quantitative information on individual processes (e.g., diffusion).
However, the movement of the immiscible phase of an organic compound (e.g., gasoline) in the subsurface,
and the effectiveness with which pools of the compound can be removed by venting, cannot be evaluated
on a laboratory scale. Large physical models coupled with numerical modeling can be useful in examining
the product movement, dissolution, volatilization, and weathering.
An example of laboratory studies was that performed by Houston ef a/. (1989). They developed a
batch-type testing method for determining the adsorptive characteristics and equilibrium adsorption
coefficients for gaseous chemical species on partially saturated soils. The effects of both water content and
surface area on the adsorptive capacity of partially saturated soils for a gaseous component were
investigated; equilibrium was reached in all tests. Houston ef a/. (1989) found that for a given soil, due to
the decrease in the surface area of soil, the sorbed mass decreased with increasing water content, provided
the solubility of the gas in water was low. They reported that other factors, such as the initial and final
concentration of the gaseous pollutant, soil mineralogy, organic content, and degree of monolayer versus
multi-layer adsorption, may be overshadowed by the available surface area for gas adsorption. Volatilization
is shown to be a significant long-term transport mechanism, and biodegradation results in the escape of
appreciable contamination to the atmosphere. Ostendorf and Kampbell (1989) have derived and field-
calibrated a model of coupled hydrocarbon and oxygen transport in a microbiologically active vadose zone
with a shallow water table.
41
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Soil venting may be used to increase biodegradation (Hinchee 1989); based upon preliminary field
work it appears that utilizing soil venting to deliver oxygen to contaminated vadose zone soils is feasible and
the system becomes less oxygen-limited. Further work has been initiated by Hinchee (1991) to maximize
biodegradation rates and minimize volatilization rates, with the objective of minimizing volatile hydrocarbon
emissions.
3.3.3. Numerical Model Studies
Mathematical models can provide valuable assistance in assessing the migration of hazardous vapors
in soil from spills of volatile chemicals, just as they have been helpful in solving the analogous problem of
contaminant transport in ground-water. Mohsen etal. (1980) and Metcalfe and Farquhar (1987) developed
mathematical models for simulating gas transport in porous media based on the continuum approach
presented by Bear (1972) for contaminant transport in ground-water. The problem is formulated, however,
in terms of molar averaged quantities rather than mass averaged quantities. Mohsen's model was applied
to select an appropriate landfill size in a given plot of land; the results indicated that the depth of the landfill
may serve as a first estimate of the trench depth. Metcalfe and Farquhar (1987) demonstrated that the
reduction of the model from three to two dimensions, assuming uniformity along the landfill boundary, is
applicable because the length of the waste disposal site boundary often exceeds gas excursion distances
by an order of magnitude.
Sleep and Sykes (1989) have developed a model that simulates water phase flow and transport, and
density-dependent gas flow and transport. The model incorporated rate expressions for dissolution,
volatilization, and gas-liquid partitioning. The authors investigated the importance of including volatilization,
gas-liquid partitioning, and advection in the gas phase for accurate determination of the fate of volatile
organic compounds in variably saturated media. They reported that volatilization and gas-liquid partitioning,
in combination with diffusion of organic vapors from the soil gas to the atmosphere, may be more important
than dissolution in dissipating residual amounts of volatile organics immobilized in the unsaturated zone.
They recommended laboratory and field studies on various fate processes for better understanding and for
model verification and validation.
Johnson era/. (1990) developed a mathematical model that can be used as a screening tool to help
determine if in situ soil venting will be a viable remediation option at any hazardous waste site. Three factors
have been shown to have significant effect on the efficiency of any soil venting operation: vapor flow-rate,
contaminant composition, and vapor flow-path relative to the contaminant location. The study presented
equations that can be used as predictive tools to estimate the behavior of various aspects of the venting
operation, such as vapor flow-rates as a function of well vacuum, or the change in residual composition with
time. Examples of model predictions are presented, and the advantages and limitations of this remediation
tool are illustrated. Thorstenson and Pollock (1989) noted the importance of including the Knudsen (1909)
diffusion, the molecular and nonequimolar components of diffusive flux, and viscous flux in studying the
multicomponent gas transport in unsaturated zones. They also discuss the adequacy of applying Fick's law
to estimate the total fluxes of stagnant gas (e.g., nitrogen) versus non-stagnant gas. They demonstrated
42
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that the error associated with estimating the total fluxes of nonstagnant relative to stagnant gases can vary
from a few percent to orders of magnitude.
Other recently developed models include those by Lin and Kinzelbach (1990), Cho (1991), and
Sabadell etal. (1991). The aforementioned studies and others demonstrate the mobility of volatile organic
constituents in the unsaturated zone, a characteristic that can be exploited by the soil venting technology.
The International Ground Water Modeling Center has compiled information regarding models that simulate
the gaseous transport of volatile compounds in the unsaturated zone (Appendix E). These models can be
invoked to assess the use of the venting technology in soil remediation.
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4. HYDROGEOCHEMICAL MODELS
Hydrogeochemical models are used to analyze chemistry of subsurface aquatic systems independent
of physical mass transport processes. The models can simulate chemical processes that regulate dissolved
species concentrations, including mixing, adsorption, ion-exchange, oxidation-reduction reactions,
complexation, and dissolution/precipitation reactions.
Hydrogeochemical codes may be used to determine what elements are expected to be mobile under
given conditions of pH, oxidizing or reducing environment, and in the presence of mineral formations
(Kincaid et al. 1984). When coupled with a transport code, they facilitate the simulation of the movement
of metals from the surface (e.g. solid and liquid waste disposal facilities) through soil formations into or
toward the ground water below. Their input requirements include one or more of the following information:
initial concentration in the aqueous (dissolved) and solid (soil-matrix) phases, temperature, thermodynamics
data base, and kinetic data base (Kincaid etal. 1984).
Coupling hydrogeochemistry and transport processes can be realized through the source/sink term
in the transport equation for the chemical species under study. There are two processes that affect the
sink/source term directly (Kincaid etal. 1984): adsorption/desorption and precipitation/dissolution. Other
chemical processes may indirectly modify the source/sink term by affecting the processes mentioned above,
(e.g., aqueous speciation, reduction/oxidation, hydration and ion interaction, kinetics, generation of gases,
and isomorphic substitution).
The focus of this section is on thermodynamic models for systems at chemical equilibrium (though
EQ3NR/6 and PROTOCOL [listed in Appendix G] contain submodels that do not require equilibrium
assumptions). Equilibrium is rigorously defined for closed systems, (i.e., systems that cannot exchange
matter with their surroundings). Since all natural ground-water systems are open systems, the time-invariant
condition describing the chemical state of the ground-water system is steady-state, not equilibrium (Rice
1986). Therefore, application of thermodynamic equilibrium models to ground-water systems must be done
with care. Although chemical equilibrium in some ground-water environments may be assumed for time
scales of tens of hundreds of years (Morgan 1967), certain processes may not approach equilibrium for
much longer periods of time; additionally, some reactions may be near equilibrium, while others in the same
system are not.
Although a system may not be at equilibrium, the thermodynamic models may be used to indicate
how close or far a reaction is from equilibrium. Although equilibrium models do not indicate the rate at
which a reaction occurs, they do yield a description of the final state toward which the system is tending
(Rice 1986).
Equilibrium models can be valuable tools in predicting the behavior of complex hydrogeochemical
systems. They do have limitations, however, and only by understanding the conceptual as well as the
computational model can they be properly applied and interpreted. To predict reliable results they need a
complete complement of important aqueous complexes, accurate thermodynamic data bases and algorithms
44
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for predicting adsorption/desorption of specific aqueous species and the transfer of elements into immobile
mineral phases (Kincaid ef a/. 1984). The following discussion, based primarily on van der Heijde ef a/.
(1988), deals with the basis for the theoretical derivation of the thermodynamic equilibrium models and
limitations of those models. Nordstrom etal. (1979), Jenne (1981), Kincaid etal. (1984), and Nordstrom and
Ball (1984) review the actual models and computer codes. An overview of currently available computer
codes is included as Appendix G.
4.1. GIBBS FREE ENERGY AND EQUILIBRIUM CONSTANTS
In any system, a process is determined to be at equilibrium when the energy function is at a minimum.
For a closed system at constant temperature T and pressure P, the energy associated with a
hydrogeochemical process is described by the Gibbs free energy function (Denbigh 1 971 , Lewis and Randall
1961, Moore 1972), which is defined as the total Gibbs free energy of the products (final state) minus that
of the reactants (initial state)
AG = cGc + dGD - aGA - bGB (42)
for the general chemical reaction
aA + bB < — > cC + dD (43)
where upper case letters represent the species, and lower case letters the appropriate stoichiometric
coefficients.
The Gibbs molar free energy for any individual species is related to the activity a, of the species by
the expression
G, = G° + RT tn a, (44)
where Gf represents the free energy of the species in a standard state condition, and fl is the gas
constant.
The expression for A G in equation (42) can be rewritten in terms of equation (44) as
ac a"
A G = A G° + RT tn -?—2 (45)
At equilibrium, the ratio of activities raised to the power of the respective stoichiometric coefficients
is equal to the equilibrium constant, K (law of mass action), and the change in total free energy, A G , is
zero; therefore
45
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-RTtn K (46)
4.2. ELECTROLYTES AND ACTIVITY COEFFICIENTS
Because equilibrium constants are defined in terms of activities, or effective solute concentrations,
it is necessary to relate these quantities to experimentally measurable concentrations. The relationship
(Moore 1972)
a, = y/m, (47)
where y, is the activity coefficient and my the concentration of a component / considered to be the solute,
is based on a standard state that obeys Henry's Law. The solution becomes ideal (y, = 1) at low solute
concentrations:
£0 3 = 1 (48)
If there are more than one solute in solution, all solutes must simultaneously conform to the limit in equation
(48).
If the expression for activity in equation (47) is substituted into equation (44), the result may be written
G, = G," + RTtn m, + RTtn y, (49)
where the terms G" + RT tn m, represent the free energy of component / in an ideal solution, i.e., one
that follows Henry's Law over the entire range of concentrations. Thus the term involving the activity
coefficient is a measure of the real solution's deviation from ideality.
It is possible to calculate single-ion activity coefficients from only electrostatic considerations. This
was first done successfully with the Debye-Huckel theory, which manages to provide surprisingly good
results despite several contradictory and physically incorrect assumptions (Bockris and Ready 1970).
Essentially, the Debye-Huckel theory ignores short-range interactions between ions of the same charge, and
thus predictions become less accurate with increasing solution concentrations. In such concentrated
solutions ions with the same charge increasingly affect each other, and those with opposite charge form ion
pairs through electrostatic attraction (Robinson and Stokes 1959).
46
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Virtually all current computer models are based on the idea of ion pairing (Bjerrum 1926, Fuoss and
Kraus 1933, Fuoss 1958). With the inclusion of these short-range ionic interactions, the modified Debye-
Hiickel equation for species / is
(50)
in which A7 and B7 are the Debye-Hiickel constants that depend on dielectric constant and temperature
and to a lesser extent pressure. z; is the ionic charge, a; an ion size parameter, and / the solution's ionic
strength, defined by the expression
/ = M2^m,zf (51)
In equation (50) the numerator accounts for long-range coulombic interactions, the denominator for short-
range interactions that arise from treating the ions as hard, finite-sized spheres. As a correction for short-
range ion-solvent interactions as well as short-range ion-ion interactions that are not accounted for by the
hard-sphere model, a linear term is often added empirically to equation (50). The extended Debye-Huckel
equation which incorporates the linear term, is given by
A z?/1/2
= ^ +
where bt is an ion-dependent empirical constant. The Davies equation (Davies 1967), a modified form of
the extended Debye-Huckel equation, given by
A z?/1/2
- - -
(53)
is frequently used to determine y, , since it is supposedly applicable to solutions of ionic strength up to
0.5M (Stumm and Morgan 1981). The Debye-Huckel equation is valid only up to about 0.1M. Thus
computer models that calculate activity coefficients by either (or both) of these equations are restricted to
fairly dilute ground water.
4.3. OXIDATION-REDUCTION REACTIONS
Of all the reactions included in any computer model, only a small fraction consists of oxidation-reduction
reactions (redox reactions). The model REDEQL-UMD (Harriss etal. 1984), for example lists only twenty-two
redox couples, and the authors caution that the kinetics of many oxidation-reduction reactions may be slow.
The emf or Nernst potential Efor any reaction involving electron transfer can be determined from the
expression (Moore 1972)
47
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where n is the number of electrons transferred, F is the faraday, and the chemical notation refers to the
general reaction in equation (43). The term E° is the standard emf of the redox reaction and can be
calculated from the standard electrode potentials of the half reactions that sum to the overall reaction
(Latimer 1952).
Because oxidation-reduction reactions can be characterized electrochemically in this manner, a
ground-water system's "redox state" can be described in terms of a single parameter, either an overall
Nernst potential, usually designated Eh (Freeze and Cherry 1979), or the negative logarithm of the electron
activity designated pe (Truesdell 1968) in analogy with Ph. The representation of the entire system by a
single parameter like pe or Eh is based on the assumption that all the oxidation-reduction reactions
occurring in the system are at equilibrium. Although this is not true (Morris and Stumm 1967, Jenne 1981,
Wolery 1983), a particular redox couple may be used as an overall indicator of the redox state of the system
(Llssetal. 1973, Cherry era/. 1979).
Lindberg and Runnells (1984) have quantitatively demonstrated the inaccuracy inherent in
characterizing an entire ground-water system by a single redox parameter. The field-measured Eh value for
each of approximately 600 water analyses was compared with the Nernst potential calculated from the data
on ten different redox couples by means of the computer model WATEQFC (Runnels and Lindberg 1981).
As these same authors (Lindberg and Runnels 1984) state: 'The profound lack of agreement between the
data points and the dashed line [which represents equilibrium points] shows that internal equilibrium is not
achieved. Further, the computed Nernstian Eh values do not agree with each other. ... If any measured
Eh is used as input for equilibrium calculations, the burden rests with the investigator to demonstrate the
reversibility of the system."
Because many of the important oxidation-reduction reactions are very slow and some are even
irreversible, it is virtually impossible that any natural-water system can reach equilibrium with respect to all
of its redox couples. Improvements in this area of computer modeling will require the inclusion of
experimental data for each of the major redox couples in the water system under study.
4.4. LIMITATIONS OF HYDROGEOCHEMICAL MODELS
Each reaction in the set listed for a particular model must be characterized by an equilibrium constant.
In any geological environment there is an extremely large number of possible reactions, and this is reflected
by the databases of many of the models, some of which consist of several hundred reactions. These include
not only reactions occurring solely in the aqueous phase, but also heterogeneous reactions between
dissolved species and solid phases, such as precipitation/dissolution and ion exchange, as well as
oxidation/reduction and degradation reactions that may be catalyzed by microorganisms in the soil.
48
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At least three fundamental problems are associated with such tabulations of thermodynamic data.
A particular species may simply be omitted from the database, so even though it is present in the physical
system being modeled, it will obviously not appear in the final speciation results nor will its effect on the
speciation of other elements. The program WATEQ3 (Ball et al. 1981), for example, is an extension of
WATEQ2 (Ball ef al. 1979) through the addition of several uranium species, but the expanded database does
not include vanadium, which frequently occurs naturally with uranium. Thus the influence of minerals
containing both elements cannot be taken into account.
Even when the database does contain particular minerals, thermochemical data for them may not be
known with very great accuracy. This problem is frequently compounded by other uncertainties, i.e., non-
stoichiometry, solution-dependent composition with respect to replaceable cations, meta-stable forms, and
variation in free energy and solubility with the degree of crystallinity (Stumm and Morgan 1981).
Only a few models include thermodynamic data which have been checked for internal consistency.
Because the data for a particular reaction may come from more than one source, there is no guarantee that
all calculations were made with consistent values of the necessary auxiliary quantities or that the data
satisfies the appropriate thermodynamic relationships. In a study done by Kerrisk (1981), experimental
solubilities of CaCO3, CaSO4, and BaSO4 in 0-4M NaCI solutions were compared to those calculated using
four different computer models: WATEQF (Plummer ef al. 1976), REDEQLEPA (Ingle ef al. 1978),
GEOCHEM (Sposito and Mattigod 1980), and SENECA2, a modification of the earlier SENECA (Ma and
Shipman 1972). Although the ionic strengths exceeded the limitations of the modified Debye-Huckel and
Davies equations, the study indicated that results for the four models frequently differed even at low ionic
concentrations. Calculations on CaCO3 by GEOCHEM differed markedly from experimental observations
even below 0.5M; one possible explanation for this is the inclusion of an equilibrium constant of about 4 for
the formation of the ion pair CaCI"1". This particular ion pair is omitted from the other three computer
models, and Garrels and Christ (1965) note that at ordinary temperatures chloride forms no significant ion
pairs with any major cation of natural waters. This clearly points to some of the dangers inherent in the ion-
air method employed in equilibrium models, and indicates another potential problem associated with the
thermodynamic databases selected for the different hydrogeochemical models.
4.5. MODELING NON-DILUTE SOLUTIONS
A different approach to the problem of ionic interactions in solution is the specific-interaction model
(Pitzer 1973), which has been applied to seawater (Whitefield 1975, Eugster ef al. 1980) and hydrothermal
brines (Weare 1981, Barta and Bradley 1985). It has been long assumed that results from the Debye-Huckel
theory could be extended by the addition of power-series corrections (Weare ef a/. 1982):
/oov- = loa Y, -t- ^ B-, (\\rn- + ^ ^ C,.^m,m^ CE&\
'9 If 'try If ^ • L*ij \' /''Ij • • ljk J k V***l
I I "
49
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where yf is the Debye-Huckel activity coefficient and B^l) and Ciik are the second and third virial
coefficients respectively (Lewis and Randall 1961), the latter of which is required only for solutions of ionic
strength greater than 3M. Pitzer (1973) has succeeded in modeling the second virial coefficient By as a
function of ionic strength and has also developed a Debye-Huckel term of the form
l°9 Y/°H = - ^=7^ + £ I" (1 + */"2) (56)
which fits experimental data better than the extended Debye-Huckel term given by equation (52).
Although the specific-interaction model is more complex mathematically, it has the distinct advantage
of not explicitly including ion pairs for ions that are only weakly associated, such as Ca2"1" and Cl". Instead,
the second virial coefficient accounts for these weak associations through dependence on the ionic strength
(Weare ef a/. 1982). Weare and his coworkers (Harvie and Weare 1980, Eugster et a/. 1980, Harvie ef a/.
1982, Harvie ef a/. 1984) have begun applying this model to simple electrolyte systems. The most
complicated thus far is one containing only 11 different ionic species, but the preliminary results appear to
be a significant improvement over calculations based on ion pairing. There is still considerable work to be
done before the specific-interaction model can be applied to ground water in general, but it clearly has the
advantage of being able to treat more concentrated solutions than ion-pair theory. Pitzer's equations have
already been or are currently being incorporated into at least three hydrogeochemical models: EQ3NR
(Wolery 1983), SOLMNEQ (Kharaka and Barnes 1973), and PHREEQE (Parkhurst ef a/. 1980).
4.6. NUMERICAL SOLUTION METHODS
Most of the existing hydrogeochemical speciation codes are based on a highly non-linear system of
equations which do not include spatial or temporal dependence (Kincaid ef a/. 1984). Solving these sets
of equations generally require two steps: reduction of the number of unknowns and solving the resulting set
of simultaneous equations. The techniques for solving the systems of equations can be grouped into four
categories: (1) iteration by simple back substitution; (2) predictive back-substitution; (3) mathematical
minimalization techniques; and (4) integration of ordinary differential equations. A more detailed discussion
of applicable solution methods can be found in Kincaid ef a/. (1984, Volume 1).
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5. STOCHASTIC MODELS
Uncertainty due to the lack of information about the system or to the variable nature in space and
time of certain properties or processes is increasingly incorporated in the analysis of ground-water systems.
Incorporating information uncertainty in stochastic analysis can produce a best estimate of output (the
mean) and a measure of the uncertainty of the estimate (the variance). On the other hand, if intrinsic
uncertainty is included, the model results can describe head (for example) as a stochastic process resulting
from an input (e.g., hydraulic conductivity) represented by a stochastic process. In other words, head is
represented, as is the case with hydraulic conductivity, as a mean trend with superimposed fluctuations
described by the covariance structure. Rather than a single answer that results from a deterministic model,
the stochastic model provides a range of answers that can be expressed through a probability distribution
function (PDF) or a number of the distribution moments. In addition, questions regarding spatial structure,
statistical homogeneity, and ergodicity of the system (see, e.g., Bakr ef a/. 1978) need to be addressed if
intrinsic uncertainty is incorporated.
Review of the stochastic approach to analyze uncertainty due to intrinsic heterogeneity have been
presented by Neuman (1982), El-Kadi (1984), and Freeze era/. (1989), among others. Deterministic models
fail because correct parameter values needed for models are not known at all locations other than those few
available measurements. Research in stochastic analysis can be divided into (1) a geostatistical approach
to estimate uncertainty in input parameters (e.g., Hoeksema and Kitanidis 1985), and (2) a simulation
approach to assess the impact of uncertainty of these parameters on model results (e.g., Bakr ef a/. 1978).
In addition, the stochastic analysis has been used to study the physics of flow and transport in fractured and
porous media. For example, it can be used to illustrate how heterogeneities affect flow patterns (Smith ef
a/. 1989), to analyze the impact of spatial variability on macroscopic dispersion (e.g., Gelhar and Axness
1983, Smith and Schwartz 1984), and to estimate effective parameters that allow the representation of the
true heterogeneous media by an equivalent homogeneous one (e.g., El-Kadi and Brutsaert 1985).
Two issues stand central in the stochastic approach. The first issue is describing the spatial
variability in probabilistic terms. In general, statistical distributions of model parameters can be estimated
through the use of the geostatistical approach to analyze available data (e.g., Hoeksema and Kitanidis 1985).
Given a set of data points located at random in space, the geostatistical approach (also known as kriging)
offers a best linear unbiased estimation of a regionalized variable (e.g., hydraulic conductivity) at various
locations. A spatial structure is used in the analysis, through the variogram which indicates the degree of
correlation between values of the variable as a function of distance. In general, an assumed distribution of
the variable (e.g., normal or log-normal) is employed and the first few moments of that distribution are used
as input to the stochastic simulation model. These moments include the expected value, the variance, and
covariance of the variable.
The second issue involves mathematical techniques to solve the stochastic equation. The available
approaches can be divided into analytical, quasi-analytical, and numerical. The analytical techniques include
derived distributions that provide an explicit expression of the PDF of the output variable (e.g., hydraulic
head) as a function of the PDF for the input variable (e.g., hydraulic conductivity). This approach also
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includes the spectral analysis technique (Bakr ef a/. 1978, Gelhar and Axness 1983) that estimates the
expected value and covariance of output parameters.
The quasi-analytical techniques include finite-order (first- or second-order) or perturbation analyses
(Sagar 1978, Dettinger and Wilson 1981). They also provide expressions for the first few moments within
a finite-element or a finite-difference framework.
The numerical approach employs the Monte-Carlo technique, i.e., the repetitive solution of the
deterministic problem for a large number of realizations, each with a set of parameters that is an equally
probable representation of the actual set of parameters. The final product is a set of answers that can be
analyzed to estimate the PDF or the first few moments of the distribution of the output variable. Example
applications of the technique are presented by Smith and Freeze (1979) and El-Kadi and Brutsaert (1985).
A decision-theory framework based on the probabilistic structure of the measured variables can be
used to assess the worth of data (Massman and Freeze 1987). An objective function that includes benefits,
costs, and risks is optimized, allowing for assessment of the economic consequences of either planning
alternative measurement strategies for a new site, or adding new measurements to an existing data
collection strategy. When additional costs are no longer balanced by the risk reduction, additional
measurements are not justified. This probabilistic modeling framework can also be used to make decisions
regarding alternative actions, such as selecting between alternative sites for waste disposal or between
alternative engineering designs for a specific site.
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6. MODELS FOR FRACTURED ROCK
Fractured rocks can be classified according to the fracture system. Metamorphic and igneous rock
are characterized by very low matrix porosities and permeability. Sedimentary rocks are characterized by
a low- to high-porosity matrix with low or high permeability, depending on rock type. Understanding
mechanisms of flow and mass transport in fractured rocks is critical, especially to the evaluation of the
suitability of waste disposal sites in geologic media.
Flow in the fractured rocks is often characterized in a complex manner by the presence of
discontinuities in the rock. These discontinuities can consist of cracks, fissures, fractures, joints, and shear
zones occurring usually in sets with similar geometries (Witherspoon era/. 1987). Flow in such systems may
take place through a channel network of interconnected fractures (Streile and Simmons 1986). Flow may
also occur simultaneously through the porous component of the media, if present. In the latter case, the
flow system is often referred to as a dual porosity system with matrix porosity as primary porosity and
fracture porosity as secondary porosity.
In porous media, the size, shape, and degree of interconnection of the pores regulate the flow rate.
The scale of these pores is small and for most purposes the medium may be treated as a continuum in
which macroscopic flow properties are considered without regard to the actual flow paths of the individual
fluid particles. In fractured rock, however, the scale of the pores (e.g., fracture space) can be large enough
that the continuum approach is not always appropriate. In such cases, the network of individual fractures
must be analyzed to understand macroscopic flow and transport properties (Endo and Witherspoon 1985).
Depending on the nature of the fracture system and the scale of analysis, Bear and Berkowitz (1987)
distinguish four different conceptual models for flow (and transport) in fractured media:
Zone 1, the very near field, where flow can be assumed to occur in a single fracture with possible
storage in the porous rock matrix block, if present;
Zone 2, the near field, where flow is assumed to occur in a well-defined set of fractures, with possible
storage in the porous block, if present;
Zone 3, the far field, where flow (and storage) in two overlapping continua are considered: a network
of fractures and porous blocks with exchange between them; and
Zone 4, the very far field, where the domain can be considered as a single continuum representing
the properties of both the fractures and porous blocks.
Considering this classification, Zones 1 and 2 can be represented mathematically by a discrete fracture
network model, Zone 3 by a double porosity (or dual-porosity) continuum model, and Zone 4 by a single
porosity continuum model (i.e., equivalent porous medium approach).
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The major issues in analyzing fluid flow through a network of fractures, where the rock matrix is
essentially impermeable, are determining the permeability of the fracture system and establishing whether
or not such networks behave more or less as a porous medium. It is often observed in the field that rock
masses contain sets of discontinuous fractures of finite size within a single plane. As a result, the degree
of interconnection between the assemblage of discontinuous fracture planes has a major influence on the
hydraulic conductivity of the total system (Witherspoon ef a/. 1987). The density, or number of fractures per
unit volume of rock, is another important feature. Finally, the orientation will determine those directions
along which the fluids may flow within the rock mass.
Flow in relatively large fissures requires a discrete fracture conceptualization where the flow within
individual fractures is modeled directly as flow in an interconnected network of channels. The lack of precise
information on the line configuration of fractures often leads to the need for stochastic representation of
fracture geometry and distribution (Streile and Simmons 1986).
Contaminant and heat transport in fractured rock formations is governed by the same processes as
in granular media: advection, mechanical dispersion, molecular diffusion, and chemical and biochemical
reactions and in the case of heat transport, conduction. However, there are some differences in the effects
that fractured media can have on these processes due to the need for a detailed description of the fluid
velocities, the sparseness of the flow channels, their unequal distribution through the rock media, and in
fractured porous rock the interaction between the fluid in the fractures and in the rock matrix. These effects
are especially noticeable in observing dispersion and diffusion processes (Schwartz ef a/. 1983, Sudicky ef
a/. 1985).
Although for the study of head distribution in a fractured system the calculation of fluxes is sufficient,
for the simulation of solute and heat transport the velocity distribution needs to be known in detail. The
velocities are determined by the active porosity (that part of the pore space in which the fluid movement
takes place), which is often much smaller than the total porosity.
Mechanical dispersion in a single fracture consists of longitudinal dispersion only. Fracture width is
generally too small to show any significant variation in the distribution of mass across the fracture. A major
contributor to macroscopic dispersion in fractured media is the geometry of the network of interconnected
fractures of limited extent (Smith and Schwartz 1984). The geometry directly determines the variability of
the fluid velocity and the average path length through the interconnecting fractures. In general, the
velocities in fractured rock are not normally distributed, precluding the use of a Gaussian dispersion model.
Macroscopic dispersion is further complicated by local mixing at the connection between fractures.
Recent advances in laboratory and field studies along with simulation models of fluid flow and solute
transport in fractured rocks have been documented in the literature. For example, Cacas et a/. (1990)
carried a large-scale experiment to investigate the flow and transport in fractured rocks. Haldeman ef a/.
(1991) conducted a laboratory experiment to determine the flow and transport properties of a fractured
porous tuff block. Rasmussen (1991) presented a laboratory flow experiment to demonstrate the interface
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concept in unsaturated fractures. Cvetkovic (1991) studied the transport of reactive solute in individual
fractures.
Mathematical models of flow in fracture systems have been based on the concept of a dual porosity
medium (Grisak and Pickens 1981, Huyakorn ef a/. 1987). A few mathematical models exist for modeling
flow and transport in saturated fractured and dual porosity media. Various analytical solutions for solute
transport in simple fractured systems are brought together in the CRACK package (Sudicky 1986). These
solutions include transport in a single fracture with matrix diffusion (but without dispersion along fracture
axis), transport in a system of parallel fractures including matrix diffusion, and transport in a single fracture
with matrix diffusion and radial diverging flow. A typical numerical model for flow and transport of heat and
nonconservative solutes in fractured rock is the TRAFRAP-WT code developed for the International Ground
Water Modeling Center (Huyakorn et al. 1987) This code is a two-dimensional finite-element code capable
of treating both confined and water table aquifers. Fractured rock can be modeled as a system of discrete
fractures or as a double porosity system by overlaying the two-dimensional element grid for the porous
medium with one-dimensional line elements representing discrete fractures. This approach requires that the
geometry of the fracture system be defined on an appropriate scale.
An example of a finite-difference model designed to handle solute and heat transport in fractured
porous media is the FRASCL code (Fractured Media - Advanced Continuous Simulation Language)
developed at the Idaho National Engineering Laboratory (Miller 1983, Clemo and Hull 1986). This code
simulates the fractured system as discrete parallel-sided channels in the porous matrix. As with the
TRAFRAP model this code allows for diffusion of chemical compounds from the liquid in the fractures into
the matrix blocks. The porous aquifer is defined by a rectangular finite-difference grid of unit thickness.
Fracture segments connect any two adjacent nodes (connectivity criterion), vertically, horizontally or
diagonally, with a maximum of eight fracture segments converging at a single node. As in TRAFRAP,
fractures can have any configuration of length, angle, and start and termination location, constrained only
by the connectivity criterion. Aperture is constant in the individual fracture segments between two directly
connected nodes, but may change in the fracture's continuation between the next set of nodes.
Recent review of approaches to modeling flow and transport in fractured rock is documented in van
der Heijde era/. (1988). Additional information regarding the theory and mathematical formulations can be
found in Bear and Berkowitz (1987), Chen (1989), Huyakorn and Pinder (1983), Evans and Nicholson (1987).
The International Ground Water Modeling Center has compiled a descriptive listing of available models for
flow and transport in fractured rocks (Appendix F).
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7. GROUND-WATER MANAGEMENT
The management of ground-water resources is concerned with their efficient use in response to
current and future demands, while protecting the integrity of the resources to sustain general environmental
needs. Resource development may include determining the location, spacing, and sizing of wells, well fields,
or other exploitation schemes, and time schedules for their operation. A successful well field project should
consider, for example, excessive pumping that may reduce natural discharge of ground water to streams
(baseflow) or capillary uptake in shallow aquifers, or that may cause land subsidence. Lowering the water
table may increase the cost of pumping and reduce the economic benefit of a project. Quality-related issues
may concern siting waste disposal facilities so that exposure, hazard, damage, and health risks are reduced
while simultaneously minimizing costs. Another example involves the cleanup of hazardous chemicals in
the subsurface within reasonable costs. In any of these examples, a decision made and implemented may
have a profound and lasting effect both economically and environmentally. Various methods exist for
evaluating alternative scenarios or designs which comprise solution strategies. Most commonly used are
ranking and screening procedures based on absolute or relative criteria. Less common, at least in ground-
water management, are optimization-based mathematical models. Among others, environmental objectives
(e.g., those concerning water quantity and quality) and economic objectives (e.g., those concerning net
benefits of a policy or engineering design) are expressed in mathematical terms, and the resulting
mathematical models are used to make design or operational decisions.
Ground-water management problems can be formulated mathematically as one or more objective
functions (e.g., environmental or economic objectives) that need to be optimized in order to estimate the
values of decision variables (e.g., pumping rates, number and location of wells) subject to a set of
constraints (e.g., maximum allowable pumping rates, minimum quality standards, limit on drawdown values,
etc.). The resulting solution is optimal only with respect to the chosen mathematical models which represent
an approximation of the real problem.
7.1. SOLUTION APPROACHES
Within the context of mathematical optimization the solution for an optimal strategy can be obtained
by (1) a simulation approach which includes sampling and search procedures, or (2) a formal optimization
approach which combines mathematical optimization with simulation.
In the simulation approach ground-water simulation models are used to evaluate alternative strategies
through an iterative procedure. The values of decision variables are specified and the resulting objective
functions are evaluated. The solution is repeated with all feasible values of decision variables. The main
advantage of the simulation approach is the ability to handle highly nonlinear objective functions and
constraints that might not be otherwise dealt with through the formal optimization approach. However, this
approach may require a large number of model runs to account for all allowable values of the decision
variables without the guarantee that an absolute optimal policy will be identified. The efficiency of the
simulation approach may be enhanced through the use of a carefully designed computational scenario or
through the solution of a simplified optimization problem in a preliminary screening phase.
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An application of the simulation approach is the allocation problem as it pertains to ground-water
(Loucks et al. 1983). It includes identifying a number of decision variables denoting pumping rates that
should be assigned to water users, in order to maximize the net benefits. To eliminate the problem of
overdrafting, the total drawdown at a specified time and location should not exceed a certain value.
For large-scale problems, systematic sampling and search procedures (Loucks etal. 1983) are used
to identify an optimal solution by examining the system performance. Either a uniform grid or random
sampling approach can be employed in evaluating the sensitivity surface. The uniform grid approach
requires evaluating the objective function at uniformly spaced values of the decision variables (in the range
of feasible values), a process that may require many simulations. On the other hand, the random approach
consists of randomly choosing feasible values of the decision variables and requires sequential search
procedures. Previous simulation results are utilized in the process to improve the performance as defined
by the value of the objective function. The simplest approach is using trial-and-error; however, its success
and efficiency depends on the modeler's understanding of the problem in adjusting the values of the
decision variables in the right direction. A formal sequential search would include calculating the rate of
increase of the objective function for a specified change in the value of the decision variables.
The mathematically formulated ground-water management problem, as an optimization problem, can
be solved using a number of techniques including Lagrange multipliers, linear programming, mixed integer
programming, dynamic programming, and quadratic programming. Details of these techniques may be
found in Hillier and Lieberman (1980) and Loucks et al. (1983). An overview of these techniques is
presented by El-Kadi ef al. (1991). The Lagrange multipliers technique can be used directly in solving the
optimization problem as formulated. Dynamic programming is suitable for allocation problems, capacity
extension, and reservoir operation. Linear programming is an efficient technique that is suitable for solving
optimization problems characterized by a linear objective function and linear constraints.
Other techniques used in ground-water applications include mixed integer programming and quadratic
programming. Mixed integer programming deals with optimization problems which include decision
variables that must assume integer values. For ground-water problems, such variables may include the
number of wells needed to satisfy certain demands. Solution of the mixed integer problem is possible
through a branch-and-bound algorithm (Dakin 1965, Hillier and Lieberman 1980). For a maximization
problem, assuming that the lower bound on the optimal objective function is known, the technique involves
trial and error that may be summarized as follows: (1) the set of all feasible solutions is partitioned into
several subsets; (2) for each subset the upper bound on the objective function is obtained; (3) the subsets
whose upper limit is smaller than the current lower bound on the objective function is excluded from further
consideration; and (4) the process is repeated within each subset and for all remaining subsets until a
feasible solution is obtained that identifies the overall optimal value of the objective function.
The quadratic programming term refers to the optimization of a quadratic objective function that is
subjected to linear constraints. The quadratic programming problem can be solved by formulating the Kuhn-
Tucker conditions (Kuhn and Tucker 1951). The problem reduces to finding a feasible solution to these
conditions, provided that the objective function is concave. The problem reduces to a linear programming
problem, which can be solved by using the modified simplex method (Sunday 1984, Kinzelbach 1986).
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For a more in-depth discussion of solution techniques used in management models, see El-Kadi et
a/. (1991).
7.2. GROUND-WATER MANAGEMENT MODELS
As described by Gorelick (1983) and Datta and Orlob (1988), based on the purpose of the analysis,
ground-water management models can be divided into water quantity or water quality models. Each group
of models can deal with ground-water management only or with the integrated use of surface and ground-
water resources. When the model aims at managing ground-water stresses, it is classified as a hydraulic
management model. Ground-water policy evaluation and allocation models, on the other hand, include a
significant economic component such as optimizing the net economic benefits, or optimizing the conjunctive
use of surface and ground-water resources.
Based on the way hydrogeologic parameters (such as hydraulic head) are represented, ground-water
management models can be classified into either lumped- or distributed-parameter models. In the lumped-
parameter approach, the management problem is formulated by including explicit solutions of the ground-
water problem (e.g., expressions relating head values to pumping rates) in the objective function or in the
set of constraints. The distributed-parameter approach is based on the representation of the hydraulic
processes through the use of the governing partial differential equations (PDEs). In general the planning
formulation consists of a solution technique for the ground-water problem combined with an optimization
scheme. A numerical solution technique is usually employed in the solution of the governing PDEs.
Although their development and use may include certain difficulties due to complexity of the analysis, the
distributed-parameter models have some advantages over lumped-parameter models insofar as they can
handle realistic situations, as when parameter spatial variability exists.
Hydraulic models can be solved either by applying the embedding method or the response matrix
method. In the first technique, numerical approximations of the governing PDEs are treated as constraints
with decision variables, such as hydraulic head, and are estimated at nodes of the discretized flow domain.
The optimization problem is generally formulated as a linear programming problem. The use of the
embedding matrix technique usually defines the decision variables at all nodes; some of them may not be
needed in the decision making. The technique is thus more suitable for relatively small aquifers where many
nodes and wells are constrained.
In the response matrix approach, the simulation model is solved to estimate the unit response of the
aquifer (e.g., for a unit pumping or recharge). Next, an assemblage of unit responses (called a response
matrix) is formulated and incorporated in the management model. The problem can be formulated as linear,
mixed integer, or quadratic programming. Constraint equations need to be formulated only for locations
and times of interest; hence, the technique is superior to the embedding matrix approach in dealing with
large-scale transient problems.
Policy evaluation and allocation models can be solved via a hydraulic-economic response approach,
which is a direct extension of the response matrix approach. A second approach involves the use of linked
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simulation-optimization, where the results of an external simulation model are used as an input to a series
of subarea economic optimization models. The third method adopts a hierarchical approach that treats
large systems as a series of independent systems with multiple objective functions.
Examples illustrating applications of the lumped- and distributed- parameter approaches to ground-
water management problems are presented in El-Kadi era/.. An overview of available management models
is presented in Appendix H.
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8. CONCLUSION AND DISCUSSION
This report presents an overview of currently available computer-based simulation models for ground-
water flow, solute and heat transport, and hydrogeochemistry in both porous media and fractured rock.
Separate sections address multiphase flow and related chemical species transport, and ground-water
management models. This report reflects the on-going ground-water modeling information collection and
processing activities at the International Ground Water Modeling Center (IGWMC).
Systematically analyzing, evaluating and characterizing the capabilities and performance of
mathematical models for studying such a complex system as encountered in managing and protecting
ground-water resources is a highly challenging activity. In recent years the amount of information resulting
from research in the many different disciplines involved has grown rapidly. Moreover, the character of the
information available and searched for by the users of this information has changed and expanded. The
IGWMC has responded to this challenge by focussing its research on code performance evaluation and the
improvement of its information systems. Currently, a microcomputer-based database containing descriptions
of more than 450 ground-water modeling codes is being tested. Plans are under development to bring this
information system in a graphic microcomputer-based environment.
In the meantime, ground-water modeling continues to evolve. A wide range of flow characterizations
are now possible. Many of the flow models include options for various types of time-varying boundary
conditions, have the ability to handle a wide variety of hydrologic processes such as evapotranspiration,
stream-aquifer exchanges, spatial and temporal variations in areal recharge and pumping or recharging
wells. Some models have options to change the field parameters during the simulation runs, thus
recognizing the potential influence of contaminants on the hydraulic parameters. Due to significant
improvements in the mathematical formulation of the soil hydraulic characteristics, the treatment of boundary
conditions and the numerical solution methods employed, models for simulating flow in the unsaturated zone
have become more accurate, realistic and reliable.
However, it may be argued that the progress in understanding the transport and fate of contaminants
has not yet resulted in a significant increase in the applicability of models to contamination problems. As
the complexity of the physics and chemistry involved in the interaction between water, soil/rock matrix and
the multi-component (sometimes immiscible) contaminant mixtures has not yet been resolved, models are
lacking to adequately simulate many of the contaminant problems encountered in the field.
The same conclusion might be drawn for modeling flow and transport in fractured rock systems.
Improved site characterization and stochastic analysis of fracture geometry, together with an improved
capability to describe the interactions of chemicals between the active and passive fluid phases and the rock
matrix, have facilitated increasingly realistic simulation of real-world fractured rock systems. However, lack
of practical field characterization methods still impedes the routine use of such models in support of
management's decision-making.
Finally, developments most promising for practical application may be found in the area of parameter
estimation. Various geostatistic and stochastic approaches have become available together with new or
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updated parameter estimation models and are increasingly used in the field, specifically in determining the
distribution of hydraulic parameters.
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APPENDICES A through J
The following appendices contain descriptive listings of selected models from the IGWMC model
information database. The models listed are considered by the authors to be relevant, available, and
current. Additional information on the models is available from the IGWMC at the Colorado School of
Mines, Golden, Colorado 80401. Model categories are: saturated ground-water flow (A), variable saturated
flow (B), solute transport (C), heat transport (D), gas flow and vapor transport in the unsaturated zone (E),
flow and transport in fractured rock (F), hydrogeochemical speciation (G), optimization for ground-water
management (H), and multiphase flow of water and non-aqueous phase liquids (I). Some of the appendices
are further divided based on dimensionality and mathematical method. Each appendix has two parts: a
table with information for evaluating a model's usability and reliability and a summary of the model's
characteristics and its contact address. Appendix J provides a cross-reference to all appendices.
The date listed for each model indicates the release date of the latest version of the code (either
released by the original author or by a code custodian) for which information has been provided to IGWMC.
Where possible the code custodian is listed as contact address; for some codes the distribution address
is listed. Contact IGWMC for information on code distribution sources.
An important aspect of a model's use is its efficiency, which is determined by the human and
computer resources required for its proper operation. A model's efficiency can be described by its usability,
availability, modifiability, portability, and economy of computer use (van der Heijde et al. 1988). Another
important issue is the model's reliability. In the appendices, usability and reliability are qualified by the
following descriptors.
USABILITY
Pre- and Postprocessors
The presence of textual or graphic pre- and postprocessing software for the simulation code is rated
as: not present [N], present [Y], or status unknown [U].
Documentation
As part of assessing the adequacy of the documentation, the presence of an adequate description
of user's instructions and example datasets is indicated by yes [Y] or no [N]. Models having no published
description of their theoretical basis are not listed in these appendices.
Support
Software support and maintenance is rated as: none [N], some available [Y], and unknown [U].
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Hardware Dependency
In this report a modeling code's hardware and/or software dependency is indicated as present [Y]
or not [N]. Hardware dependency may be due to the size of the source code, the way it has been designed
and compiled, the use of specific peripherals, and graphics calls in the program. In addition, programs may
be software-dependent, requiring specific program purchases to reside on the user's computer (e.g.,
graphics or mathematical routines).
RELIABILITY
Review
This report identifies peer-review of theory and coding. For each category the rating is: peer-reviewed
[Y}, not peer-reviewed [N], and unknown [U]. A model is considered to be peer-reviewed if theory and
code has been subject to a formal review process such as established by certain agencies (eg., U.S. EPA,
U.S. Geological Survey). In addition, a model's theory is considered to be peer-reviewed if it has been
published in a peer-reviewed publication.
Verification
A code's verification status is rated as: 1) code has been subject to extensive verification [E], e.g.
tested for most of its functions and features, and verification results are available; 2) code has been subject
to partial verification, e.g. tested for selected functions and features, or only selected verification tests are
available [L - limited]; 3) code verification results (if performed) are not available [N]; 4) IGWMC has no
information regarding the code's verification [U]. It should be noted that most models have been verified
only with respect to segments of their coding or for only a part of the tasks for which they were designed,
and thus have been subject to only partial or limited verification.
Field Testing
In this report, model field testing, the application of codes to site-specific conditions for which
extensive datasets are available, is rated as performed, either extensively or in a limited fashion [Y], not
performed [N], or unknown [U].
Extent of Model Use
This report evaluates the extent of a model's use in four classes: many [M, >10], few [1-10], none
[N], and unknown [U]. The evaluation is used on IGWMC's information regarding published reports, journal
and proceedings papers, conference presentations, and non-published case history summaries provided
by model authors and users.
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AVAILABILITY
The programs listed are either general-use codes, or relatively easy-to-obtain research codes. Many
of the codes are in the public domain, some are proprietary. In most case, the contact address listed is that
of the code custodian or principal distributor.
For USGS software contact:
National Water Information System, Water Resources Division, U.S. Geological Survey, 437
National Center, 12201 Sunrise Valley Drive, Reston, VA 22092.
For EPA software contact:
Center for Subsurface Modeling Support (CSMoS), R.S. Kerr Environmental Research Lab., U.S.
Environmental Protection Agency, P.O. Box 1198, Ada, OK 74820.
Center for Exposure Assessment Modeling (CEAM), Environmental Research Lab., U.S.
Environmental Protection Agency, Athens, Georgia 30613-0801.
Many public domain and proprietary programs (including ready-to-run USGS and EPA software) are
distributed by:
International Ground Water Modeling Center (IGWMC), Colorado School of Mines, Golden,
Colorado 80401.
Another major source for groundwater software is:
Scientific Software Group, P.O. Box 23041, Washington, D.C. 20026-3041
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Appendix A.I: Saturated Flow; Analytical Models, Part 1: Model Description
IGWMC Key: 683 Model Name: IMAGEW-I Released: 1973
Author: White, W.A.
IMAGEW-I is an analytical well-field drawdown model for steady-state and time-varying pumping. The wells
may be located in either a confined (Theis equation; no recharge) or an unconfined aquifer (Jacob's
water-table correction for the non-steady-state Theis equation or Walton's modified steady-state solution for
a water table aquifer with recharge). The model assumes that the aquifer is homogeneous and isotropic
with respect to its parameters, and infinite in areal extent. Image well theory is used to simulate the effects
of hydrogeologic boundaries.
Contact Address: Texas Dept. of Water Resources, P.O. Box 13087, Austin, TX 78758
IGWMC Key 1791 Model Name: SLAEM/SLW/SLWL/SYLENS Released: 1992
Author: Strack, O.D.L
SLAEM and its predecessor SYLENS are models for analysis of two- and three-dimensional steady-state and
transient groundwater flow in single or multi-layered aquifer systems based on the Analytical Element
Method. SLAEM is an highly interactive graphic oriented program including many of the analytical elements
available. The program includes transient wells, areal inhomogeneities, leaky or draining objects, variable
infiltration (e.g. from rivers, lakes, and ponds). It allows analysis of flow in two aquifers separated by a thin
confining layer. The model is especially suited to analyze flow in regional double aquifer systems with local
interconnections. SLW and SLWL are scaled-down, educational versions of the SLAEM program.
Contact address: O.D.L Strack, Univ. of Minnesota, Dept. of Civil Eng., Minneapolis, MN 55455
IGWMC Key: 1820 Model Name: FLOP/FLOP-LIESTE/FLOP-Z1/FLOP-ZN Released: 1820
Authors: Van den Akker, C., R. Lieste, and E.J.M. Veling.
The FLOP models are semi-analytical models for calculation of pathlines and residence times in groundwater
systems. FLOP-LI ESTE is designed for single (semi-) confined aquifers; FLOP-Z1 for a quasi
three-dimensional semi-confined aquifer system; and FLOP-ZN for a multi-layered homogeneous aquifer
system.
Contact Address: RIVM - National Institute for Health and Environment, P.O. Box 1, 3720 AB
Bilthoven, The Netherlands
IGWMC Key: 1822 Model Name: FRONT Released: 1981
Author: Van den Akker, C.
FRONT is a semi-analytical model for calculation of pathlines and residence times in a confined, isotropic,
heterogeneous aquifer with steady-state or transient flow. The integration along the streamlines is performed
with Runge-Kutta, restricting the maximum time step size with a user-provided error-criterion.
Contact Address: RIVM - Nat. Inst. for Health and Environment, P.O. Box 1, 3720 BA Bilthoven, The
Netherlands
A. 1-1-1
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 2120 Model Name: PATHS Released: 1980
Author: Nelson, R.W.
The PATHS program is an idealized hybrid analytical/numerical model for simulation of steady-state or
transient, two-dimensional, saturated groundwater flow and single component transport. It includes an
analytical solution of the flow equation and the Runge-Kutta solution for the pathline equations and the
effects of equilibrium ion-exchange and linear adsorption. The model calculates pathlines, location/arrival
time distribution, and location/outflow quantity distribution in a confined stratum of uniform vertical
thickness. It assumes a uniform lateral flow gradient and superimposed leakage from a vertical, cylindrical
fully penetrating pond or cavern and handles up to 35 fully penetrating wells or vertical line sources.
Contact address: Battelle Pacific NW Laboratories, P.O. Box 999, Richland, WA 99352
IGWMC Key: 2770 Model Name: CONFLOW Released: 1981
Author: Hertel Jr., E.S.
The computer code CONFLOW describes fluid flow between two wells in a confined homogeneous, isotropic
region. The code uses superposition to solve Laplace's equation with impermeable boundaries and can
assist in the design of flow experiments in geologic media. CONFLOW's output is a plot of the theoretical
streamlines, the ratio between the time of first arrival for the confined region and the time of first arrival for
unconfined two-well flow, and a value for the pressure drop function.
Contact address: E.S. Hertel Jr., Sandia National Laboratories, Albuquerque, NM 87185
IGWMC Key: 2791 Model Name: CRREL (Flow Lines Program) Released: 1984
Author: Daly, C.J.
CCREL is an analytical model to calculate and plot streamlines for flow in anisotropic, heterogeneous
aquifers based on known head distribution.
Contact Address: R. Reynolds, U.S. Army Corps of Engineers, Cold Regions Research & Engineering
Lab., Hanover, NH 03755
IGWMC Key: 3940 Model Name: RESSQ Released: 1985
Authors: Javandel, I., C. Doughty and C-F. Tsang
RESSQ is a semi-analytical model of 2-dimensional contaminant transport that calculates the streamline
pattern in an aquifer, the location of contaminant fronts around sources at specified times, and concentration
versus time at sinks. RESSQ assumes a homogeneous, isotropic confined aquifer of uniform thickness and
a steady-state regional flow field. It can handle advection and linear equilibrium adsorption. Sources are
represented by fully penetrating recharge wells and ponds, and sinks are represented by fully penetrating
pumping wells.
Contact address: I. Javandel, Lawrence Berkeley Lab., Earth Sc. Div., Berkeley, CA 94720, or Internal.
Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
A. 1-1-2
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 3943 Model Name: WHPA Released: 1992
Authors: Blandford T.N., and P.S. Huyakorn
WHPA is an integrated program of analytical and semi-analytical solutions for the groundwater flow equation
coupled with pathline tracking. It is designed to assist technical staff with delineation of wellhead protection
areas. Developed for the U.S. EPA's Office of Groundwater Protection, the package includes modules for
capture zone delineation in a homogeneous aquifer with 2-dimensional steady-state flow with options for
multiple pumping/injection wells and barrier or stream boundary conditions. Also included are modules for
Monte Carlo analysis of uncertainty and a particle-tracking postprocessor for numerical flow models such
as MODFLOW and PLASM, using a two-dimensional rectangular grid.
Contact address: P. Berger, U.S. Environmental Protection Agency, Office of Groundwater Protection,
Washington, D.C., or Internal. Ground Water Modeling Ctr., Colorado Sch. of
Mines, Golden, CO 80401.
IGWMC Key: 4670 Model Name: DREAM Released: 1990
Authors: Bonn, B.A., and S.A. Rounds
DREAM is a menu-driven, user-interactive series of analytical programs for the calculation of drawdowns,
water level elevations, steady-state velocities and streamlines in homogeneous and isotropic aquifers. The
program uses a commercial contouring package for graphic display of results.
Contact address: Lewis Publishers, Inc. 2000 Corporate Blvd. N.W., Boca Raton, FL 33431
IGWMC Key: 4730 Model Name: GW-UN/DTCD Released: 1991
Authors: Karanjac, J. and D. Braticevic
The UN/DTCD Ground Water Software Series, currently, includes the following ten programs for general
groundwater evaluation: 1) hydraulic conductivity calculations and conversions from grain size distributions,
permeameters and pumping tests; 2) chemistry data base; 3) aquifer tests (Theis, Jacob, Hantush, recovery,
Rushton's dug well test); 4) well construction and hydraulics (including well functions and step-drawdown
test); 5) finite difference model for a confined aquifer; 6) a finite difference model for unconfined/confined
aquifer; 7) water level data base and hydrograph presentation; 8) preprocessor for USGS 3D Flow Model
for 2-layer system; 9) numerical model of a small island with salt-water/freshwater interface; and 10) lithology
database and graphic display.
Contact address: Uri Golani, U.N., Dept. of Techn. Coop, for Developm., Water Resources Branch,
United Nations Building DC-1, Room 745, New York, NY 10017
IGWMC Key: 5003 Model Name: MLU (Multi-Layer Unsteady-state model) Released: 1986
Author: Hemker, C.J.
MLU is a program for drawdown calculations and inverse modeling (aquifer tests) of transient flow in layered
(up to 9 aquifers) and fissured (double porosity aquifer systems of (semi-)confined and unconfined
conditions. The model is based on a series of analytical solutions.
Contact Address: Hemker, C.J., Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
A. 1-1-3
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 5004 Model Name: MFLOP (FLOw Pattern) Released: 1989
Author: Hemker, C.J.
MFLOP is a simple microcomputer program for the immediate generation of streamlines of well fields with
superimposed uniform flow under confined conditions.
Contact address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands.
IGWMC Key: 5100 Model Name: ANALYTICAL MODELS Released: -
Authors: --
The modular program ANALYTICAL MODELS can handle confined, unconfined, and leaky conditions.
Module 1 creates time-drawdown data for observation wells. Aquifer parameters can be varied and graphed
on the same chart. Module 2 graphs profiles along lines drawn on a map. Pumping wells and observation
wells are shown. Module 3 creates contour and 3D maps of grids, up to 100x100, with 50 wells.
Contact address: Earthware of California, 30100 Town Center Drive, Laguna Niguel, CA 92677
IGWMC Key: 5130 Model Name: FINITE Released: --
Author: Koch, D.H.
FINITE is a program for simulation of the inflow to mines, dewatering schemes, the impact of excavations
on groundwater levels, and any other hydrogeologic situation involving finite length lines of recharge or
discharge. The program is based on the analytical solution by Muskat for steady-state flow to a finite length
line sink in an infinite homogeneous confined or unconfined aquifer. The menu-driven program extends the
Muskat algorithm to transient problems using the method of successive states, assuming that the
potentiometric surface has a steady-state curvature at all points in time. Both constant head or constant
flow sources or sinks may be simulated. This program handles up to 40 finite length line sources or.
Contact Address: Koch and Associates, 2921 Greenway Drive, Ellicot City, MD 21043
IGWMC Key: 5131 Model Name: LEAKY Released: -
Author: Koch, D.H.
LEAKY - Leaky Aquifer Analysis is a menu-driven, interactive program that uses the leaky well function
developed by Hantush and Jacob to simulate the drawdowns from multiple wells in a leaky aquifer.
Although this algorithm assumes infinite storage in the overlying bed, it is a useful approximation of the
performance of an aquifer. By using the theory of superposition, one can simulate variable discharging
wells, boundary conditions, and injection wells. The program permits the user to simulate up to 100 wells.
Contact Address: Koch and Associates, 2921 Greenway Drive, Ellicot City, MD 21403
A.1-1-4
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 5140 Model Name: GLOVER Released: -
Author: Spinks, M.P.
GLOVER is an analytical model based on the Glover-Balmer equation for simulation of the depletion from
or accretion to surface water due to pumping or recharging wells. The model is valid for a homogeneous,
isotropic, twodimensional aquifer. Boundary conditions are either constant-head (e.g. fully penetrating rivers)
or no-flux (e.g. impermeable boundary). The software provides various graphic input/output options.
Contact address: Microcode, Inc., 2473 Camino Capitan, Santa Fe, NM 87501
IGWMC Key: 5150 Model Name: HYDROPAL Released: --
Authors: --
HYDROPAL is an interactive, menu-driven set of analytical and numerical solutions of groundwater flow and
contaminant transport problems. The numerical models are adaptations of the PLASM and RANDOM WALK
models. The program creates ASCII output for postprocessing in a graphical package.
Contact address: Watershed Research Inc., 4779 126th St. N, White Bear Lake, MN 55110.
IGWMC Key: 5171 Model Name: THEIS Released: -
Author: Spinks, M.P.
THEIS is an analytical model for simulation of potentiometric surface drawdown or buildup effects due to
pumping or injecting wells in a homogeneous, isotropic, twodimensional aquifer. Boundary conditions are
either constant head or no-flux. User can specify grid for areal calculation of potentiometric surface changes.
Contact address: Microcode, Inc., 2473 Camino Capitan, Santa Fe, NM 87501
IGWMC Key: 5172 Model Name: THEIS2 Released:-
Authors: Koch, D.H.
THEIS2 is an aquifer analysis program which simulates up to 100 wells in a confined aquifer using the Theis
equation. With a modification developed by Jacob, the equation can be used for unconfined aquifers. By
using the theory of superposition, one can simulate variable discharging wells, boundary conditions, and
injection wells. The program calculates drawdown at a particular time for an array of locations, or for a
single location drawdown versus time.
Contact address: Koch and Associates, 2921 Greenway Drive, Ellicot City, MD 21043
IGWMC Key: 5176 Model Name: STREAMLINE Released: -
Authors: Koch, D.H.
This program computes and plots groundwater flow streamlines in a homogeneous, isotropic, and confined
aquifer under influence of pumping wells and a uniform regional gradient. Travel times along a streamline
or path line may also be computed.
Contact address: Koch and Associates, 2921 Greenway Drive, Ellicot City, MD 21043
A. 1-1-5
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 5300 Model Name: QUICKFLOW Released: 1991
Authors: -
QUICKFLOW is an interactive analytical model that simulates two-dimensional steady-state and transient
ground-water flow. The steady-state module simulates flow in a horizontal plane using analytical functions
developed by Strack (1989), including wells, uniform recharge, circular recharge/discharge areas, and line
sources or sinks in confined and unconfined aquifers. The model generates streamlines, particle traces and
head contours. The transient module calculates heads using equations developed by Theis (1935) and by
Hantush and Jacob (1955) for confined and leaky confined aquifers, respectively, and includes a particle
tracking option. Each module uses the principle of superposition to evaluate the effects of multiple wells
in a uniform regional flow field.
Contact address: Geraghty & Miller, Inc., 10700 Park Ridge Blvd., Suite 600, Reston, VA 22091
IGWMC Key: 5391 Model Name: CSUPAW Released: 1985
Author: Sunada, S.K.
The interactive program CSUPAW (Colorado State University Pit And Well)allows the user to predict the
response of a water-table to discharge from wells or artificial recharge of water from rectangular basins in
a homogeneous aquifer of infinite areal extent, in a homogeneous stream-aquifer system, or in an aquifer
having a vertical impermeable boundary. The model calculates discharge (recharge) to the stream in a
stream-aquifer system at times specified by the user. Utilization of graphics allow visual evaluation of results.
The program is based on Glover's (1960) analytical solution for recharge from a rectangular basin.
Contact Address: O.K. Sunada, Dept. of Civil Eng., Colorado State Univ., Fort Collins, CO 80523
IGWMC Key: 5570 Model Name: FLSTAT Released: 1988
Authors: Lieste, R., E.J.M. Veling, and C. van den Akker.
FLSTAT (FLow STATionary) is a program for forwards and backwards calculation of streamlines and
residence times, given the two-dimensional areal distribution of hydraulic heads is known (from field
measurements or flow model). It assumes a rectangular model domain with a grid of rectangular elements,
which can be refined locally. The model requires as input the hydraulic conductivity in x- and y-direction
and the porosity per element. The coupled differential equations are solved explicitly. The model includes
an automatic time-step control routine. The streamlines are calculated from user-specified starting points.
The program can provide plot output for hydraulic head contours, streamlines and isochrones.
Contact Address: R. Lieste, Nat. Inst. for Public Health and Environm. Protect., P.O. Box 1, 3720 BA
Bilthoven, The Netherlands
A.1-1-6
-------
Appendix A. 1, part 1 (continued)
IGWMC Key: 5710 Model Name: AQMODEL Released: 1992
Author: O'Neill, G.T.
AQMODEL calculates drawdown, equipotentials (according to the Thiem formula) and stream functions
(following McWhorter and Sunada) for a steady, uniform flow field, and drawdowns and equipotentials for
unsteady flow fields with the Theis equation. The interactive program handles over 500 wells and can be
used to determine capture zones and well head protection areas. The user can plot flow nets, contour maps
of heads and other custom graphics using SURFER for IBM compatibles and or Spyglass Transform
software for Macintosh.
Contact Address: WellWare, 3160 Woods Circle, Davis, CA 95616
IGWMC Key: 5790 Model Name: MAP (Multiple Aquifer Flow) Released: 1984
Authors: Roelse, A., and K. Maas.
The MAF program includes a number of analytical solutions for ground-water flow in systems comprising
of multiple aquifers. The functions were derived through application of matrix functions in the superposition
of linear closed-form solutions. Among others, the program includes generalized functions of De Glee,
Mazure, Bosch, Theis, Hantush and Edelman for n-layer systems.
Contact Address: K. Maas, Provincial Dept. of Water Management Zeeland, P.O. Box 165, 4330 AD
Middelburg, The Netherlands
IGWMC Key: 5920 Model Name: TIM1/TIM2 Released: 1987
Authors: Jiin-Shuh, J., and D.I. Leap
TIM1 and TIM2 use the trajectory image method (TIM), a modeling technique based on image theory, to
calculate heads, gradients, velocities, and flow directions. TIM is based on the concept that particles emitted
by sources or absorbed by sinks may be reflected by impermeable boundaries, or they may be partially
absorbed, reflected, and partially transmitted by boundaries of differing hydraulic conductivities. Particles
move till their changes in head become negligible. The total head and gradients at each observation point
are found by superposing heads and gradients of particle trajectories that pass through or close to the
observation point. Combination of TIM with a boundary integral equation method (BIEM), resulting in
TIMBIE, reduces computational requirements.
Contact Address: D.I. Leap, Dept. of Earth and Atmospheric Sciences, Purdue University, West
Lafayette, IN 47907.
IGWMC Key: 6022 Model Name: THWELLS Released:!992
Author: van der Heijde, P.K.M.
THWELLS is an analytical model for transient groundwater flow in an isotropic homogeneous nonleaky
confined aquifer with multiple pumping and injection wells using superposition of Theis solutions. Boundary
effects can be included through use of image wells. The program includes a correction for a water table
aquifer and superposition of local drawdown on a regional, sloping, stationary piezometric surface.
Contact address: Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
A. 1-1-7
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 6023 Model Name: GWFLOW 1990
Author: van der Heijde, P.K.M.
GWFLOW is a menu-driven series of seven simple programs, each containing an analytical solution to a
groundwater flow problem. The program contains solutions for transient drawdown in confined and
semi-confined aquifers, including the effects of partially penetrating wells; circular recharge of a water table
aquifer; and stream depletion resulting from pumping an aquifer.
Contact address: Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6350 Model Name: WALTON35 Released: 1985
Author: Walton, W.C.
WALTON35 is a package containing a series of simple BASIC programs for simulating flow, solute transport,
and heat transport in various types of aquifers. The programs are based on analytical and numerical
solutions of the governing equations. Included are various analytical solutions for non-conservative solute
transport in a homogeneous aquifer. The programs are interactive, simple to use, and easy to modify.
Contact address: Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6351 Model Name: WELFUN/WELLFLO/CONMIG Released: 1989
Author: Walton, W.C.
The programs WELFUN, WELFLO and CONMIG calculate common well function values and simulate a wide
range of ground-water flow and contaminant migration situations based on analytical solutions. The
program options include: (1) drawdown or recovery due to multiple production and/or injection wells with
variable discharge or recharge rates, drains, and mines; (2) confined, leaky confined, and water table
conditions with barrier and/or recharge boundaries and discontinuities; and (3) development of localized
contaminant plumes from slug or continuous source areas of various shape and sizes due to advection,
dispersion, retardation caused by linear adsorption, and radioactive decay.
Contact address: Lewis Publ. Inc., 2000 Corporate Blvd., N.W. Boca Raton, FL 33431
IGWMC Key: 6352 Model Name: GWPT Released: 1987
Author: Walton, W.C.
GWPT is a series of analytical groundwater flow programs for use in aquifer test analysis. It includes models
for pumping test design, semilog time-drawdown or distance-drawdown analysis, storativity analysis near
a stream, stream depletion analysis and drawdown beneath a streambed. Furthermore, the package
includes programs for calculation of the (confined aquifer) Well function, the partial penetration well function,
the leaky aquifer well function, the well loss coefficient and other equations.
Contact address: Lewis Publishers, Inc., 2000 Corporate Blvd. N.W., Boca Raton, FL 33431
A.1-1-8
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 6383 Model Name: HWELL Released: 1991
Author: Beljin, M.S.
HWELL is an interactive analytical model, developed to simulate steady-state or transient groundwater flow
towards a horizontal well in a confined aquifer. The model can handle different vertical and horizontal
hydraulic conductivities (anisotropy), and includes options for skinfactor and eccentricity of the well. The
program also computes drawdown and specific capacity of a fully penetrating vertical well in the same
aquifer. Performance of the two wells is compared by computing the specific capacity ratio as a function
of screen length, hydraulic conductivity contrast, aquifer thickness, and other parameters. The program
includes windows, mouse support and graphic output.
Contact address: M.S. Beljin, Univ. of Cincinnati, Dept. of Civil & Env. Eng., Cincinnati, OH 45221
IGWMC Key: 6570 Model Name: OPTP/PTEST Released: 1986
Authors: Paudyal, G.N., and A. Das Gupta
OPTP/PTEST is a fully interactive package consisting of two programs for determining optimal well
discharge. PTEST computes the coefficients and exponent of the nonlinear drawdown equation using data
from a step-drawdown test. OPTP computes the optimal discharge using a single-variable constrained
nonlinear programming algorithm.
Contact address: A. Das Gupta, Asian Inst. of Technology, Div. of Water, P.O. Box 2754, Bangkok
10501, Thailand, or Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401.
IGWMC Key: 6590 Model Name: BEAVERSOFT Released: 1987
Authors: Bear, J. and A. Verruijt
BEAVERSOFT is a package of analytical and numerical solutions for groundwater flow and solute transport.
It includes programs for steady and non-steady state two-dimensional flow in heterogeneous aquifers, for
flow through dams, for transport of pollutants by advection and dispersion and for saltwater intrusion
problems.
Contact address: Internat. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6604 Model Name: PAT Released: 1990
Authors: Kinzelbach, W. and R. Rausch
PAT is an analytical model for the computation and graphical representation of pathlines and travel times
of groundwater in an infinite or semi-infinite, homogeneous and isotropic confined aquifer or in an infinite
strip of such an aquifer. The computed steady-state flow field might include arbitrary pumping or injection
wells superposed on a natural uniform regional flow. The model is screen-oriented and fully interactive.
Contact address: W. Kinzelbach, Geasamthochschule Kassel - Universitat, Moritzstrasze 21, D-3500,
Kassel, Germany, or Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401.
A. 1-1-9
-------
Appendix A.1, part 1 (continued)
IGWMC Key: 6681 Model Name: AQUIX Released: 1992
Authors: -
AQUIX is a series of programs for the interactive, forward and inverse modeling of pumping test data. It
provides drawdowns in terms of aquifer storativity, transmissivity, leakage, anisotropy, and specific yield,
depending on the model selected. A least squares, nonlinear curve fitting method is used to determine the
best fit model parameters to the observed data. AQUIX include programs for partial penetrating wells, and
for confined, leaky confined and unconfined aquifers. The models are based on Theis (1935), Hantush
(1960,1965), and Neuman (1975). The model comes with a sophisticated textual and graphic user-interface.
Contact address: R.S. Bell, Interpex Ltd., 715 14th Street, Golden, CO 80401
A.1-1-10
-------
Appendix A.1: Saturated Flow; Analytical Models, Part 2: Usability and Reliability
IGWMC
Key
683
1791
1820
1822
2120
2770
2791
3940
3943
4670
4730
5003
5004
5100
5130
5131
5140
5150
5171
5172
Model
IMAGEW-1
SLAEM/SLW/
SLWL/SYLENS
FLOP/
FLOP-LIESTE/
FLOP-Z1/
FLOP-ZN
FRONT
PATHS
CONFLOW
CRREL
RESSQ
WHPA
DREAM
GW-UN/DTCD
MLU
MFLOP
ANALYTICAL
MODELS
FINITE
LEAKY
GLOVER
HYDROPAL
THEIS
THEIS2
Usability
w
O
:
u
s.
a.
£
N
Y
Y
Y
Y
U
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
o
8
2
Sf
s
a
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
o
a.
a.
(0
N
Y
Y
Y
N
Y
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
U
U
U
U
U
Y
Peer Reviewed Coding
N
Y
U
U
Y
U
U
Y
Y
N
N
U
U
U
U
U
U
U
U
U
Verified
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
U
Y
U
U
Field Tested
N
Y
Y
Y
Y
U
U
Y
Y
N
Y
Y
U
U
U
U
U
U
U
U
£
i
1
u
M
M
M
F
U
U
M
M
M
M
U
M
M
U
U
U
U
U
U
KEY: Y = YES N = NO M = MANY F = FEW U = UNKNOWN
A. 1-2-1
-------
Appendix A.1, part 2 (continued)
IGWMC
Key
5176
5300
5391
5570
5710
5790
5920
6022
6023
6350
6351
6352
6383
6570
6590
6604
6681
Model
STREAMLINE
QUICKFLOW
CSUPAW
FLSTAT
AQMODEL
MAP
TIM1/TIM2
THWELLS
GWFLOW
WALTON35
WELFUN/
WELLFLO/
CONMIG
GWPT
HWELL
OPTP/PTEST
BEAVERSOFT
PAT
AQUIX
Usability
Preprocessor
Y
Y
Y
Y
Y
N
N
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Postprocessor
Y
Y
Y
Y
Y
N
N
Y
N
N
N
Y
N
U
N
Y
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
imple Problems
(0
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
grdware Dependency
X
Y
Y
Y
Y
Y
N
N
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
r
o
Q.
a.
(0
Y
Y
Y
Y
Y
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A. 1-2-2
-------
Appendix A.2: Saturated Flow; Numerical Models For Two-Dimensional Flow in Horizontal or
Vertical Plane, Part 1: Model Description
IGWMC Key: 322 Model Name: PLASM Released: 1990
Authors: Prickett, T.A., and C.G. Lonnquist
PLASM (Prickett Lonnquist Aquifer Simulation Model) is a finite difference model for simulation of transient,
two-dimensional or quasi-three-dimensional flow in a single or multi-layered, heterogeneous, anisotropic
aquifer system. The original model of 1971 consisted of a series of separate programs for various
combinations of simulation options. Later versions combined most of the options in a single code, including
variable pumping rates, leaky confined aquifer conditions, induced infiltration from a shallow aquifer or a
stream, storage coefficient conversion between confined and watertable conditions, and evapotranspiration
as a function of depth to watertable. The model uses the iterative alternating implicit method (IADI) to solve
the matrix equation.
Contact Address: T.A. Prickett and Assoc., Inc., 6 G.H. Baker Drive, Urbana, IL 61801, or Internal.
Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 514 Model Name: AQUIFEM Released: 1979
Authors: Pinder, G.F., and C.I. Voss
AQUIFEM is a two-dimensional finite element model for the simulation of transient, areal saturated
groundwater flow in an isotropic, heterogeneous, confined, leaky-confined, or water table aquifer with areal
recharge and distributed wells. It incorporates steady-state or transient leakage through confining layers.
The model is based on ISOQUAD (1971); a water-balance calculation was added in 1974. This version,
called AQUIFEM, includes groundwater velocity calculations and other modifications.
Contact Address: C.I. Voss, U.S. Geol. Survey, Water Resources Div., M.S. 431, Reston, VA 22092
IGWMC Key: 681 Model Name: GWSIM Released: 1974
Author: Knowles, T.R.
GWSIM (GroundWater SIMulation program) is a finite difference model for simulation of transient,
two-dimensional, horizontal flow in a heterogeneous, anisotropic, single-layer aquifer. The program allows
simulating flow in a confined, unconfined, or leaky confined aquifer. It uses an iterative alternating direction
implicit procedure to solve the matrix equations.
Contact Address: Texas Dept. of Water Resources, P.O. Box 13087, Austin, TX 78758
IGWMC Key: 741 Model Name: USGS FRONT-TRACKING Released: 1983
Authors: Garabedian, S.P., and LF. Konikow
USGS FRONT-TRACKING is a finite difference model for simulation of advective transport of a conservative
tracer dissolved in groundwater under steady or transient flow conditions. The model calculates heads,
velocities and tracer particle positions.
Contact Address: LF. Konikow, U.S. Geological Survey, Water Resourc. Div., 431 National Center,
Reston, VA 22092
A.2-1-1
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 771 Model Name: USGS-2D-FLOW Released: 1976
Authors: Trescott, P.C., G.F. Pinder, and S.P. Larson.
USGS-2D-FLOW is finite difference model to simulate transient, two-dimensional horizontal flow in an
anisotropic and heterogeneous, confined, leaky-confined or water-table aquifer. It uses the iterative
alternating-direction implicit approximation of the ground-water flow equation.
Contact Address: L.J. Torak, U.S. Geological Survey, Branch of Groundwater, M.S. 411 National
Center, Reston, VA. 22092
IGWMC Key: 772 Model Name: SSIM3D Released: 1987
Authors: Trescott, P.C., S.P. Larson, and D.B. Sapik
SSIM3D is a modification of the USGS three-dimensional flow model developed by Trescott and Pinder
(1975) to simulate steady flow of fresh water in a multiple aquifer system containing fresh water and static
salt water. The two fluids are assumed immiscible, with constant densities and separated by a sharp
interface. In addition to heads, boundary fluxes and global water balance, the finite difference model
calculates the location of the interface.
Contact Address: District Chief, U.S. Geological Survey, 1201 Pacific Avenue - Suite 600, Tacoma,
WA 98402
IGWMC Key: 1230 Model Name: AQU-1 Released: 1979
Authors: Rushton, K.R., and LM. Tomlinson
AQU-1 is a simple finite difference model for simulation of transient, two-dimensional horizontal groundwater
flow in a heterogeneous, anisotropic confined or leaky-confined aquifer.
Contact address: Rushton, K.R., University of Birmingham, Dept. of Civil Engineering, P.O. Box 363,
Birmingham, BIS 2TT, United Kingdom
IGWMC Key: 1852 Model Name: SWIFT Released: 1982
Authors: Verruijt, A., and J.B.S. Gan.
SWIFT (Salt Water Interface by Finite element Technique) is a transient, cross-sectional finite element model
to simulate flow of fresh and salt water in a confined, semi-confined or water-table aquifer of homogeneous
permeability and porosity. The purpose of the model is the computation of the upconing of a sharp interface
between the fresh and salt water.
Contact Address: Verruijt, A., Delft Technical University, Dept. Civil Engineering, Stevinweg 1, 2628
CN Delft, The Netherlands
A.2-1-2
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 2091 Model Name: VTTSS2 Released: 1979
Authors: Reisenauer, A.E., and C.R. Cole.
VTTSS2 is a finite difference model to predict steady-state hydraulic head in confined aquifer systems up
to five layers. The solution is achieved by the Newton method for non-linear equations followed by direct
Gaussian elimination. The model can handle cell-by-cell water budget computations and provides
streamlines and traveltimes.
Contact Address: Cole, C.R., Battelle Pacific NW Laboratories, Water and Land Resources Division,
P.O. Box 999, Richland, WA 99352
IGWMC Key: 2092 Model Name: VTT Released: 1979
Authors: Reisenauer, A.E., and C.R. Cole.
VTT (Variable Thickness Transient Groundwater Flow Model) is a finite difference model to calculate transient
hydraulic head in confined or unconfined isotropic, heterogeneous, multi-layered aquifer systems. The
model can calculate cell-by-cell water budgets and can generate stream-lines and travel times. Boundary
conditions and aquifer stresses may be time-varying. The transient model is solved with the line successive
over-relaxation method (LSOR).
Contact Address: Cole, C.R., Battelle Pacific NW Laboratories, Water and Land Resources Division,
P.O. Box 999, Richland, WA 99352
IGWMC Key: 2140 Model Name: SWSOR Released: 1980
Authors: Mercer, J.W., and C.R. Faust
SWSOR is a finite difference model for simulation of two-dimensional area), unsteady flow of saltwater and
freshwater separated by a sharp interface in an anisotropic heterogeneous aquifer. There are two separate
differential equations for flow of fresh water and of salt water. The model can handle water-table conditions
or confined conditions with steady-state leakage of fresh water.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 2510 Model Name: Quasi 3-D Multiaquifer Model Released: 1978
Author: Weeks, J.R.
This is an IADIP finite difference model to simulate transient or steady-state groundwater flow in isotropic,
heterogeneous multi-aquifer systems using a quasi-three dimensional approach. Uniform recharge to each
layer and distributed discharge can be simulated. Specified head boundaries can be simulated in the
uppermost aquifer. Outflows to the specified head boundaries are computed for each time period and as
cumulative volume of water.
Contact address: Weeks, J.R., U.S. Geological Survey, Box 25046, MS 412 Denver Federal Center,
Lakewood, CO 80225
A.2-1-3
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 2630 Model Name: AQUIFEM-1/AQUIFEM-N Released: 1989
Authors: Townley, L.R., J.L Wilson, and A.S. Da Costa.
AQUIFEM-1 /AQUIFEM-N is a finite-element model for transient, two-dimensional or quasi-three-dimensional
groundwater flow in confined, leaky-confined, or unconfined single or multi-layered aquifers. Later versions
allow for a wide variety of aquifer and boundary conditions and facilitate two-dimensional cross-sectional
simulation, and simulation of groundwater discharge into streams, simulation of springs, partial penetrating
wells and drains, and simulation of aquifer or aquitard pinch-outs. AQUIFEM-N is a multilayered version of
AQUIFEM-1, developed by L Townley at CSIRO, Australia. It includes grid generation and node
renumbering programs, and allows plotting of grids, contours, flow lines, time series and cross-sections.
Contact Address: Ralph M. Parsons Lab. for Water Resources & Hydrodyn., Massachusetts Inst. of
Technology, Cambridge, MA 02139 (single-layer version); CSIRO Division of Water
Resources, Private Bag, PO Wembley, W.A. 6014, Australia (multi-layer version)
IGWMC Key: 2631 Model Name: SWIM Released: 1979
Authors: Sa da Costa, A.G., and J.L Wilson
SWIM (Salt Water Intrusion Model) is a versatile finite element model for simulation of transient, horizontal
flow of fresh and salt water separated by a sharp interface. The model can handle various aquifer conditions
and boundary conditions.
Contact Address: Ralph M. Parsons Lab. for Water Resources and Hydrodynamics Dept. of Civil
Engineering, Mass. Inst. of Technology, Cambridge, MA 02139
IGWMC Key: 2640 Model Name: TRIAG Released: 1979
Authors: Mallory, M.J., and T.J. Durbin
TRIAG is a Galerkin finite element model for simulation of steady and nonsteady-state ground-water flow in
an isotropic, heterogeneous, two-aquifer system with leakage through the separating confining layer. The
area! extent of the two aquifers do not have to coincide. Discharge and recharge can be varied spatially
and with time. Evapotranspiration is treated as a linear function of depth to water. The model uses a
backwards finite difference approximation for time.
Contact Address: Mallory, M.J., U.S. Geological Survey, Water Resources Division, 345 Middlefield
Rd., Menlo Park, CA 94025
IGWMC Key: 2720 Model Name: INTERFACE Released: 1979
Author: Page, R.H.
INTERFACE is a finite element model to simulate transient flow of fresh and saline water as immiscible fluids
separated by a sharp interface in an isotropic, heterogeneous, water table aquifer. The model can handle
both confined and unconfined aquifers. The flow equations for the two fluids are coupled by assuming
equality of pressures on either side of the interface.
Contact Address: Water Resources Program, Dept. of Civil Engineering, Princeton University,
Princeton, NJ 08540
A.2-1-4
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 2800 Model Name: SGMP Released: 1981
Authors: Boonstra, J., and N.A. De Bidder
SGMP is a polygon-based, integrated finite difference model for simulating steady-state or transient,
two-dimensional, horizontal flow in a saturated, anisotropic and heterogeneous, confined, semi-confined or
phreatic aquifer.
Contact Address: J. Boonstra, Internal. Inst. for Land Reclam. and Improvement, P.O. Box 45,
Wageningen, The Netherlands
IGWMC Key: 2870 Model Name: DISIFLAQ Released: 1980
Author: Berney, O.
DISIFLAQ (Digital Simulation of FLow through a 2-layer AQuifer system) is a polygon-based finite difference
model for steady-state or transient simulation of two-dimensional, horizontal groundwater flow in a one- or
two-layer, isotropic, heterogeneous aquifer system. The model computes the position of the piezometric
surface of the aquifer(s), the distribution of flux rates within the aquifers and across the leaky confining layer
between or above the aquifers, the flux rates across the boundaries (springs, streams, etc.), and the
distribution of storage changes in the aquifer(s). Also, the program computes the piezometric head
variations in time for any point and aquifer.
Contact Address: Land and Water Developm. DK/., U.N. F.A.O., Via Delle Terme Di Caracalla,
00100-Rome, Italy
IGWMC Key: 3101 Model Name: GWFLOW/GWMESH/GWPLOT Released: 1991
Authors: Warner, J.W., and D.D. Walker
GWFLOW is a two-dimensional finite element flow model, based on a solution of the linearized Boussinesq
equation using triangular elements and linear shape functions. The model has a choice of two solvers: a
banded Gauss algorithm and a preconditioned conjugate gradient solver. A preprocessor, GWMESH, helps
the user interactively design the mesh, organize the input data, interpolate non-uniform aquifer properties,
and edit input for the GWFLOW model. The package also includes GWPLOT, a postprocessor and graphics
program to view the mesh and provide for contouring of the simulation results.
Contact Address: J.W. Walker, Colorado State University, Ground Water Program, Engineering
Research Center, Fort Collins, CO 80523
IGWMC Key: 3237 Model Name: PORSTAT/PORMC Released: 1983
Authors: Sagar, B., and P.M. Clifton
PORSTAT is a numerical model solving the two-dimensional stochastic groundwater flow equation, optionally
coupled with the deterministic heat transfer and mass transfer equations using integrated finite differences
coupled to a direct equation solver. The stochastic groundwater modeling is achieved by means of a
second-order uncertainty analysis (using sensitivity coefficients), based on a Taylor series expansion of the
state variables of interest (hydraulic heads and Darcian velocities) about the expected values of the model
parameters. Uncertain variables which can be considered are hydraulic conductivities, specific storage,
(continued )
A.2-1-5
-------
Appendix A.2, part 1 (continued)
PORSTAT/PORMC - continued
boundary conditions, and initial conditions. To assess the accuracy of PORSTAT, a Monte Carlo
groundwater flow program (PORMC) was developed.
Contact Address: Rockwell Hanford Operations, Basalt Waste Isolation Project, P.O. Box 800,
Richland, WA 99352
IGWMC Key: 3240 Model Name: GM5 (Groundwater Model 5) Released: 1982
Author: Liggett, J.A.
GM5 is a model using the boundary integral equation method (BIEM) for simulation of steady state or
unsteady quasi-three-dimensional saturated groundwater flow in an anisotropic, heterogeneous, regional
multi-aquifer system. The aquifers may be confined or unconfined. Boundary conditions include specified
head and specified flux. The model has options for distributed recharge and point-specific pumping or
injection wells.
Contact Address: Liggett, J.A., School of Civil and Environmental Engineering, Hollister Hall, Cornell
University, Ithaca, NY 14853
IGWMC Key: 3241 Model Name: Seawater Intrusion with BIEM Released: 1983
Authors: Taigbenu, A.E., J.A. Liggett, and A.H-D. Cheng.
The purpose of this model is to simulate sea-water intrusion under transient confined and steady-state
unconfined aquifer conditions using the Boundary Integral Equation Method.
Contact Address: Liggett, J.A., School of Civil and Environmental Engineering, Hollister Hall, Cornell
University, Ithaca, NY 14853
IGWMC Key: 3350 Model Name: FEMSAT Released: 1978
Author: Van Bakel, P.J.T.
FEMSAT is a finite element model for simulation of transient two-dimensional horizontal flow in a saturated
heterogeneous, anisotropic multi-layered aquifer system.
Contact Address: Van Bakel, P. J.T., Institute for Land and Water Management Research, P.O. Box 35,
6700 AA Wageningen, The Netherlands
IGWMC Key: 3372 Model Name: AQUIFLOW Released: 1984
Authors: Yeh, G.T., and C.W. Francis
AQUIFLOW is a two-dimensional finite element model to simulate transient flow in horizontal, anisotropic,
heterogeneous aquifers under confined, leaky or unconfined conditions.
Contact Address: Yeh, G.T., Penn State University, Dept. of Civil Eng., 225 Sackett Building,
University Park, PA 16802
A.2-1-6
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 3373 Model Name: FEWA Released: 1983
Authors: Yeh, G.T., and D.D. Huff
FEWA (Finite Element model of Water flow through Aquifers) is a two-dimensional finite element model to
simulate transient vertically averaged flow in confined, leaky confined, or water table aquifers. The fluid flow
is a function of pressure gradient and gravity. The model incorporates infiltration and evapotranspiration,
leakage, and artificial injection and withdrawal. The aquifer may be partially confined and partially
unconfined. The grid may include both quadrilateral and triangular elements. The resulting matrix equations
are solved using a pointwise iteration solution strategy as optional alternatives to the direct solution method.
Contact Address: Yeh, G.T., Penn State University, Dept. of Civil Eng., 225 Sackett Building,
University Park, PA 16802.
IGWMC Key: 3600 Model Name: SWIGS2D Released: 1982
Author: Contractor, D.N.
SWIGS2D is a two-dimensional finite element model to simulate transient, horizontal salt and fresh water flow
separated by a sharp interface in an anisotropic, heterogeneous, confined, semi-confined or water table
aquifer. The model solves the depth-averaged equations for continuity for fresh water and salt water
simultaneously using linear, triangular elements. Boundary conditions of the Dirichlet and/or Neumann type
can be applied. Pumping rates, recharge rates, and boundary conditions can be specified as function of
time. The program can track the location of salt water toes and the fresh water toes (where the phreatic
surface touches the impervious base). The program can provide the magnitude and direction of fresh and
salt water velocities in each element.
Contact Address: Contractor, D.N., University of Arizona, Dept. of Civil Eng. & Mech. Eng., Tuscon,
AZ 85721
IGWMC Key: 3640 Model Name: SEAWTR/SEACONF Released: 1980
Author: Allayla, R.I.
SEAWTR/SEACONF is a two-dimensional finite difference model for simulation of simultaneous horizontal
flow of salt and fresh water separated by a sharp interface in a confined or water table aquifer with
anisotropic and heterogeneous properties, including effects of capillary flow.
Contact Address: Colorado State University, Civil Engineering Department, Fort Collins, CO 80523
IGWMC Key: 3881 Model Name: 2-D Finite Element Galerkin Model Released: 1984
Author: Tracy, J.V.
This Galerkin finite element model simulates steady and transient two-dimensional ground-water flow in an
irregularly shaped confined or unconfined aquifer. The aquifer's transmissive and storage properties may
be heterogeneous. The model accounts for gains and losses from the river flow in each reach based on
the incoming river and tributary flows and the gain/loss of the aquifer in each reach. With an estimate of
river discharge, the river stage is computed for each reach using an input stage-discharge relationship.
(continued )
A.2-1-7
-------
Appendix A.2, part 1 (continued)
2D Finite Element Galerkin Model - continued
The river-aquifer gains/losses are calculated as a function of streambed area, riverbed leakance values, and
the head gradient between river and aquifer. Well discharge can vary and evapotranspiration is calculated
monthly. BCs include specified flux and head.
Contact Address: U.S. Geol. Survey, WATSTORE Program Off., 437 Nat. Center, Reston, VA 22092
IGWMC Key: 4100 Model Name: MODFE Released: 1992
Authors: Torak, L.J., and R.L Codey
MODFE is a modular finite element model to solve two-dimensional steady-state or transient groundwater
flow in (leaky) confined or unconfined, heterogeneous and anisotropic aquifers. The program uses triangular
elements with linear basis functions and the extended Galerkin method of weighted residuals. Boundary
conditions may be specified as a point, line, or areally distributed sources or sinks, depending on the nature
of the field problem. Fluxes from these boundaries may be specified, or may be computed as a function
of hydraulic head during the simulation (third type b.c.). Spatially distributed parameters may be specified
for individual elements or for zones of elements. The discretized equations are solved using a modified
incomplete-Cholesky, conjugate gradient method.
Contact Address: Torak, L.J., U.S. Geological Survey, Branch of Groundwater, M. S. 411 National
Center, Reston, VA 22092, or WATSTORE Program Office, 437 National Center,
Reston, VA 22092
IGWMC Key: 4160 Model Name: ST2D Released: 1985
Author: El-Kadi, A.I.
ST2D is a two-dimensional stochastic model to solve gravity drainage into adjoining streams using the Monte
Carlo technique. The program consists of three sections: a generator for hydraulic conductivity realization,
a deterministic finite element groundwater flow simulator, and a statistical analysis routine. The flow
simulation is based on the two-dimensional Boussinesq equation with linearized hydraulic conductivity.
Contact Address: Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, CO 80401
IGWMC Key: 4530 Model Name: MAQWF Released: 1986
Authors: Contractor, D.N., S.M.A. El Didy, and A.S. Ansary.
MAQWF is a finite element model for simulation of transient two-dimensional horizontal flow in a multiple
aquifer system with time-varying boundary conditions. The program handles both confined and unconfined
aquifer conditions and allows local confined/unconfined conversion during the simulation. The model
provides velocities to be used as input for a transport model.
Contact Address: Contractor, D.N., University of Arizona, Department of Civil Eng. and Mech. Eng.,
Tuscon, AZ 85721
A.2-1-8
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 4640 Model Name: RAQSIM Released: 1985
Authors: Cady, R.E., and J.M. Peckenpaugh
RAQSIM (Regional AQutfer SIMulation) is a two-dimensional finite element model for transient regional
aquifer simulation with support programs for evapotranspiration using the Jensen-Haise method, for
infiltration, storage, and removal of water from the soil zone using climatic data, evapotranspiration data and
soil characteristics, and for computing recharge and discharge from the groundwater system, including
stream-aquifer flux.
Contact Address: District Chief, U.S. Geological Survey, 406 Federal Building, 100 Centennial Mall
North, Lincoln, NE 68508
IGWMC Key: 4753 Model Name: AQ-FEM Released: 1989
Authors: Leijnse, A., and K. Kovar.
AQ-FEM is a finite element model for computation of the head distribution in a multi-layered, anisotropic
heterogeneous aquifer-aquitard system. The model handles both steady-state and transient flow conditions.
The program package consists of 3 modules: (1) AQ-EG is a finite element grid generator, (2) AQ-DD is used
to allocate spatially variable data to the FEM grid, and (3) AQ-EP is the finite element simulator. The
program is menu-driven and has extensive error checking, help features and graphic post-processing.
Contact Address: Nat. Inst. of Public Health and Environm. Protection, P.O. Box 1, 3720 Bilthoven,
The Netherlands
IGWMC Key: 4754 Model Name: AQ-EF Released: 1989
Authors: Leijnse, A., and K. Kovar
AQ-EF is a menu-driven, interactive computer program package for calculation of ground-water streamlines
and isochrones in multi-layered, anisotropic heterogeneous aquifer-aquitard systems with steady-state or
transient flow conditions. The program handles forward or backward particle tracking using the head
distribution values computed by the program AQ-FEM. The package includes a module for plotting of the
results.
Contact Address: Nat. Inst. of Public Health and Environm. Prot., P.O. Box 1, 3720 BA Bilthoven, The
Netherlands
IGWMC Key: 4900 Model Name: SLAM Released: 1990
Author: Aral, M.M.
SLAM (Steady Layered Aquifer Model) is a finite element groundwater model for simulation of steady-state
flow in multilayered aquifers. The model can handle a system of up to five (leaky-)confined aquifers with
the top aquifer either confined or unconfined.
Contact Address: Lewis Publishers, Inc. c/o CRC Publishers, Inc., 2000 Corporate Blvd., N.W., Boca
Raton, FL 33431
A.2-1-9
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 4901 Model Name: UNSTEADY FLOW Released: 1990
Author: Aral, M.M.
UNSTEADY FLOW is a finite element model for simulation of unsteady flow in multilayered aquifers. The
model can handle up to 5 layers and allows for confined, semi-confined and water-table conditions.
Contact Address: Lewis Publishers, Inc. c/o CRC Publishers, Inc., 2000 Corporate Blvd., N.W., Boca
Raton, FL 33431
IGWMC Key: 4920 Model Name: FLOWPATH Released: 1992
Authors: Franz, T., and N. Guiguer.
FLOWPATH is an easy-to-use program for the analysis of two-dimensional steady- state groundwater flow
problems. The program calculates hydraulic head distributions, groundwater velocities, pathlines, travel
times, capture zones, and wellhead protection areas in confined, leaky-confined or unconfined, anisotropic,
heterogeneous aquifers. Pathlines are computed with a particle tracking method. The finite difference
model can handle up to 10,000 nodes in an irregular grid, over 100 wells, and over 100 zones of different
aquifer properties. The program has extensive and sophisticated post-processing capabilities.
Contact Address: Waterloo Hydrogeologic Software, 113-106 Seagram Drive, Waterloo, Ontario,
Canada N2L 3B8
IGWMC Key: 5000 Model Name: MICROFEM Released: 1989
Authors: Hemker, C.J., and H. van Elburg
MICROFEM is a user-friendly series of programs to create and analyze a wide range of multi-layer
steady-state groundwater flow problems using the finite element technique. The simulation technique is
embedded in an elaborate, partially graphic, user-interface for data entry and editing; triangular element grid
generation and optimization; and display of grid, contoured simulation results, flow-vectors, and flowlines.
The model also calculates waterbalances and traveltimes. The program consists of three main programs
and two optional utilities to plot graphics on a HP-plotter and to compile a new model data set by overlaying
an existing model with a new network.
Contact Address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
IGWMC Key: 5001 Model Name: FLOWNET Released: 1989
Authors: Van Elburg, H., C.J. Hemker, and G.B. Engelen
FLOWNET is used for interactive modeling of two-dimensional steady-state flow in an heterogeneous and
anisotropic cross-section of the saturated zone. It generates a flownet, composed of flow lines and
equipotential lines, obtained by a five-point finite difference approximation to calculate heads and linear
interpolation to determine equipotential lines. The matrix equation is solved using the conjugate gradient
method. The streamlines are determined from the flow function which in turn is determined using the adjoint
function of the potential function. The model handles hydraulic head boundary conditions variable along
the boundary. It has options for waterbalance calculations and HP-plotter output.
Contact Address: C.J. Hemker, Elandsgracht 83, 1016TR Amsterdam, The Netherlands
A.2-1-10
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 5030 Model Name: NUSEEP Released: 1990
Authors: -
NUSEEP is a collection of four IBM-PC compatible programs designed to allow for the rapid solution of
steady-state groundwater flow problems in two dimensions using the boundary element method. The
software computes piezometric head and boundary fluxes. The soil is presumed non-deformable,
homogeneous and saturated. The solution of a groundwater flow problem begins with the construction of
a boundary mesh and the specification of boundary conditions (boundary flux if heads are to be calculated,
or heads if boundary flux is unknown). The software includes graphics post processing to create
piezometric head contours and boundary configuration.
Contact Address: Northwestern Univ., Dept. of Civil Eng., 2145 Sheridan Road, Evanston, IL 60208
IGWMC Key: 5110 Model Name: AQUIFER Released:--
Authors: -
AQUIFER is a quasi three-dimensional finite difference groundwater flow model. It accepts real geologic
columns in geologic terms at each node, using formation names for which the user defines the
hydrogeologic parameters. Up to 12 pumping wells can be simulated with variable flow rates. The program
handles rivers, lakes and other boundary conditions. The model switches automatically between confined
and unconfined conditions at each node, dependent on the head and the geologic column.
Contact Address: J.C. Hall, Island Design, 518 Town Hill Road, New Hartford, CT 06057
IGWMC Key: 5160 Model Name: INTERSAT Released: -
Author: Voorhees, M.
INTERSAT is an interactive finite difference groundwater flow program for transient, quasi-three dimensional
simulation of complex aquifers systems and boundary conditions. The program includes pre- and
postprocessing as well as contour graphics. It has optional SIP and ADI solvers, calculates water budgets,
and computes velocity distributions for use in a solute transport model.
Contact Address: ESE/Hydrosoft, 63 Sarasota Center Boulevard, #107, Sarasota, FL 34240
IGWMC Key: 5200 Model Name: FLOWNS Released: 1989
Authors: Bramlett, W., and R.C. Borden.
FLOWNS is a simple-to-use program for generating two dimensional flow nets for steady-state flow in any
saturated rectangular domain with any combination of constant head or constant flux (including zero flux)
boundary conditions. The domain might be either horizontally (areal) or vertically (cross-section) oriented.
The program approximates with discrete values the continuous distributions of potential and stream function
using finite difference approximations of the Laplace equation. The hydraulic conductivity distribution may
be anisotropic and/or heterogeneous. A contouring program is required to generate the final stream and
equipotential lines.
Contact Address: R.C. Borden, North Carolina State University, Civil Engineering Department, Box
7908, Rayleigh, NC 27695
A.2-1-11
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 5230 Model Name: GEOFLOW Released: -
Authors: -
GEOFLOW is a computer program to solve two-dimensional, cross-sectional steady-state seepage problems.
It can simulate confined and unconfined systems. The plotting option plots the finite element mesh, the top
flow line, and specified equipotentials on the screen, printer and plotter. GEOFLOW is based on the finite
element program FEDAR, originally developed at the University of California at Berkeley. Modifications
provide solutions for flow, gradients, and heads. For unconfined flow the program modifies the position of
the phreatic surface iteratively. The program includes an automatic mesh generator.
Contact Address: GEOCOMP Corporation, 66 Commonwealth Avenue, Concord, Mass. 01742
IGWMC Key: 5240 Model Name: CGAQUFEM Released: -
Authors: -
CGAQUFEM is a Galerkin finite element model for simulating 2-dimensional, transient groundwater flow in
plan view. It computes the distribution of heads and groundwater velocities in a confined, unconfined or
mixed aquifer. It can handle area! recharge when unconfined (or leakage through an aquitard from a water
table aquifer if confined). Aquifer and aquitard thickness and hydraulic conductivity, initial head, recharge
and pumping (injection) rates are node-wise variable. The matrix solution is provided by incomplete
Cholesky decomposition and a conjugate gradient solver. The latter reduces core storage requirements
significantly for large problems when compared to conventional solvers.
Contact Address: Waterloo Centre for Groundwater Research, University of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5241 Model Name: FLONETS Released: -
Authors: -
FLONETS is 2-dimensional Galerkin finite element model for simulating steady-state groundwater flow in
cross-section. It computes the distribution of heads, stream functions and groundwater velocities. It
includes a mesh generation option for rectangular grids (it can seek the water table in this case). It can also
read a manually generated grid. Vertical and horizontal hydraulic conductivity, porosity and principal
direction angle are element-wise variable. Matrix solution is by the Cholesky decomposition method.
Contact Address: Waterloo Centre for Groundwater Research, University of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5392 Model Name: CSUFDM Released: 1986
Authors: Close, B., J. Warner, G. Sunada, and O.K. Sunada
CSUFDM (Colorado State University Finite Difference Model) is a finite difference model for steady-state or
transient two-dimensional areal flow in a single-layer heterogeneous, anisotropic confined, semi-confined,
or unconfined aquifer. The model uses an implicit, central finite difference formulation for which is solved
using Gauss elimination. The model employs a dynamic core allocation. The user can specify impermeable
(no-flow), constant head, and underflow boundary conditions. The model calculates at any time interval
(continued )
A.2-1-12
-------
Appendix A.2, part 1 (continued)
CSUFDM - continued
head distribution, discharge rates between grid cell, discharge to and from streams, mass balance, and
difference in head between initial head and current head. The model has an interactive input and (graphic)
output processor.
Contact Address: O.K. Sunada, Groundwater Program, Dept. of Civil Eng., Colorado State Univ., Fort
Collins, CO 80523
IGWMC Key: 5540 Model Name: FRESAL Released: 1980
Author: Kovar, K.
FRESAL is a finite element model for calculation of the steady-state interface between salt and fresh water
in the subsurface. The program can be used for problems dealing with a single aquifer, completely or
partially overlain by a semi-permeable layer, or two aquifers separated by a semi-permeable layer. In the
latter case, the saline-fresh water interface is situated in the lower aquifer, with only fresh water in the upper
aquifer. The model assumes flow in the fresh water section to be horizontal and in the semi-permeable layer
to be vertical. Saline groundwater flow is ignored. Density effects are introduced by using the saline
groundwater potential.
Contact Address: National Inst. for Health and Environm. Prot., P.O. Box 1, 3720 BA Bilthoven, The
Netherlands
IGWMC Key: 5720 Model Name: JDB2D/3D Released: 1991
Author: Bredehoeft, J.D.
JDB2D/3D consists of two fairly simple, easy modifiable general-use computer programs for solving the 2D
and quasi-3D formulation of the transient ground-water flow equation for (leaky-)confined aquifers. The
governing equations are approximated using central finite differences for the spatial derivatives together with
a block-centered formulation. Intercell transmissivities are taken as the harmonic mean of adjacent cell
transmissivities. The FD equations are solved using the Strongly Implicit Procedure (SIP). The model requires
a no-flow boundary around the area of computational interest, and assumes a leaky confining layer, an
inactive source layer above the confining unit and pumping for every cell of interest. Source functions are
used to approximate bc's other than no-flow.
Contact Address: J.D. Bredehoeft, U.S. Geol. Survey, Branch of Research, Menlo Park, CA 94025
IGWMC Key: 5730 Model Name: AQUAMOD Released: -
Authors: van Tender, G., and H. van Rensburg.
AQUAMOD is a triangular 2-D finite element confined flow model. Abstraction rates may be changed at any
time. Recharge is input by either supplying a constant value over the whole of the aquifer or a different
recharge rate at each node. Dirichlet and Neumann boundary conditions can be handled. Output includes
heads at each time step together with Darcian velocities. The program comes with a number of utilities: 1)
GENDRIEH, which generates a simple triangular finite element mesh with rectangular sides; 2) TFEM, which
generates a triangular finite element mesh from any given set of points using Delaney triangufarization; KRIG,
(continued )
A.2-1-13
-------
Appendix A.2, part 1 (continued)
AQUAMOD - continued
which uses ordinary or universal kriging to interpolate T and S values and water levels; and $) Bayes, for
Bayes interpolation of water levels.
Contact Address: van Rensburg, H.J., Dept. of Water Affairs, Private Bag X313, Pretoria, South Africa
IGWMC Key: 5750 Model Name: SHARP Released: -
Author: Essaid, H.I.
SHARP is a quasi-three-dimensional finite difference model for simulating freshwater and saltwater flow
separated by a sharp interface in layered coastal aquifer systems. The interface tip and toe positions are
tracked within each layer. The model accommodates multiple aquifers separated by confining layers, with
spatially variable porous media properties. The uppermost aquifer can be confined, unconfined, or
semi-confined with areally distributed recharge. Temporal variations in recharge and pumping are accounted
for by multiple pumping periods. The boundary conditions which can be simulated include prescribed flux
boundaries, constant freshwater head and/or constant saltwater head boundaries, and head-dependent flux
boundaries in the upper-aquifer. Fresh water and salt water mass balances are calculated for each layer.
The equations are solved using the strongly implicit procedure. The model is verified against experimental
and analytical solutions.
Contact Address: H.I. Essaid, U.S. Geol. Surv., 345 Middlefield Road, MS 421, Menlo Park, CA 94025
IGWMC Key: 5810 Model Name: 2D Steady-State FE model Released: 1989
Author: Kuniansky, E.L
This model program is a simple finite element model for simulation of two-dimensional steady-state
ground-water flow in heterogeneous, anisotropic, confined aquifers. Constant head, constant flux, and
head-dependent flux boundary conditions an be specified. The model uses triangular elements.
Contact Address: E.L. Kuniansky, Water Resources Div., U.S. Geological Survey, 8011 Cameron
Road, Bldg. 1, Austin, TX 78753
IGWMC Key: 6030 Model Name: AQ/BASIC GWF Released: 1989
Author: Verruijt, A.
BASIC GWF is a simple finite element model for analysis of plane steady- or unsteady-state groundwater
flow in an isotropic, heterogeneous, confined or unconfined aquifer. AQ is an updated version facilitating
user-friendly interactive data entry and editing and graphic display of simulation results.
Contact Address: A. Verruijt, Technical University Delft, Dept. of Civil Eng., Stevinweg 1, 2628 CN
Delft, The Netherlands
A.2-1-14
-------
Appendix A.2, part 1 (continued)
IGWMC Key: 6353 Model Name: GWFL3D Released: 1989
Author: Walton, W.C.
GWFL3D is a finite difference model for simulation of transient groundwater flow in multilayered confined,
leaky confined and water-table aquifer systems. The model allows for partially penetrating wells, well storage
capacity, multi-aquifer production wells, flowing wells, mine excavations, induced infiltration from streams,
subsurface drains, aquitard storativity and delayed gravity yield.
Contact Address: Lewis Publishers, Inc. c/o CRC Publishers, Inc., 2000 Corporate Blvd. N.W., Boca
Raton, FL 33431
IGWMC Key: 6650 Model Name: GWPATH Released: 1990
Author: Shafer, J.M.
GWPATH is an interactive microcomputer-based software package for estimating horizontal or vertical fluid
pathlines and traveltimes in fully saturated ground-water flow domains. The model is applicable to
two-dimensional heterogeneous, anisotropic flow systems, and features forward and reverse pathline
tracking, time-related capture zone analysis, and multiple pathline capture detection mechanisms. It requires
as input a regular, cell-based distribution of observed or computed hydraulic heads.
Contact Address: J.M. Shafer, 1013 Devonshire Drive, Champaign, Illinois 61821
Note: See also Appendix C.2; many 2-D solute transport models include a flow simulation module.
A.2-1-15
-------
Appendix A.2: Saturated Flow; Numerical Models For Two-Dimensional Flow in Horizontal or
Vertical Plane, Part 2: Usability and Reliability
IGWMC
Key
322
514
681
741
771
772
1230
1852
2091
2092
2140
2510
2630
2631
2640
2720
2800
2870
3101
Model
PLASM
AQUIFEM
GWSIM
USGS FRONT-
TRACKING
USGS-2D-FLOW
SSIM3D
AQU-1
SWIFT
VTTSS2
VTT
SWSOR
Quasi-3-D
Multiaquifer
Mode!
AQUIFEM-1/
AQUIFEM-N
SWIM
TRIAG
INTERFACE
SGMP
DISIFLAQ
GWFLOW/
GWMESH/
GWPLOT
Usability
Preprocessor
Y
N
N
N
Y
N
N
Y
U
Y
N
N
Y
N
N
N
N
N
Y
Postprocessor
Y
N
N
N
Y
N
N
Y
U
Y
N
N
Y
N
N
N
N
N
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
N
Y
U
N
Y
U
U
N
N
Y
N
N
N
Y
Y
Y
4M
*
a
&
10
Y
N
N
Y
N
U
N
Y
N
N
N
N
Y
N
N
N
N
N
U
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
Y
U
U
U
U
U
N
U
U
U
U
U
U
U
U
Verified
E
E
L
L
E
L
L
L
L
L
L
L
E
L
L
L
L
L
L
Field Tested
Y
U
Y
U
Y
U
U
U
U
U
U
U
U
U
U
U
U
U
U
8
1
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F
F
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U
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F
M
F
U
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U
U
U
M
M
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
A.2-2-1
-------
Appendix A.2, part 2 (continued)
IGWMC
Key
3237
3240
3241
3350
3372
3373
3600
3640
3881
4100
4160
4530
4640
4753
4754
4900
4901
Model
PORSTAT/
PORMC
GM5
Seawater
Intrusion with
BIEM
FEMSAT
AQUIFLOW
FEWA
SWIGS2D
SEAWTR/
SEACONF
2-D Finite
Element Galerkin
Model
MODFE
ST2D
MAQWF
RAQSIM
AQ-FEM
AQ-EF
SLAM
UNSTEADY
FLOW
Usability
Preprocessor
N
N
N
N
N
N
N
N
N
Y
N
N
N
Y
Y
N
N
5
8
o
o
s
a-
§
Q.
N
N
N
N
N
N
N
N
N
Y
N
N
N
Y
Y
N
N
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
Y
U
U
U
Y
Y
N
N
N
Y
N
N
N
Y
Y
Y
Y
•*
o
a
a.
(0
U
N
N
U
N
N
N
N
N
N
N
N
N
Y
Y
Y
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
U
U
N
U
U
N
N
N
U
U
U
U
Verified
L
L
L
L
L
L
L
L
L
E
L
L
L
L
L
L
L
•o
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KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
A.2-2-2
-------
Appendix A.2, part 2 (continued)
IGWMC
Key
4920
5000
5001
5030
5110
5160
5200
5230
5240
5241
5392
5540
5720
5730
5750
5810
6030
6353
6650
Model
FLOWPATH
MICROFEM
FLOWNET
NUSEEP
AQUIFER
INTERSAT
FLOWNS
GEOFLOW
CGAQUFEM
FLONETS
CSUFDM
FRESAL
JDB2D/3D
AQUAMOD
SHARP
2D Steady State
FE Model
AQ/BASIC GWF
GWFL3D
GWPATH
Usability
j
^
a
a
Y
Y
Y
Y
U
Y
N
Y
U
U
Y
N
N
Y
N
N
Y
Y
N
5
«
a.
(0
o
a.
Y
Y
Y
Y
U
Y
N
Y
U
U
Y
N
N
Y
N
N
Y
Y
N
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Support
Y
Y
Y
Y
Y
Y
Y
Y
U
U
Y
N
Y
Y
N
N
Y
Y
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
u
u
N
U
N
N
N
N
N
U
N
U
U
U
U
Verified
E
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
•a
S
0
2
iL
Y
Y
Y
U
U
U
U
U
U
U
U
N
U
U
U
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U
U
U
£
CO
1
M
M
M
U
U
F
U
M
U
U
F
F
M
U
U
F
M
M
M
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
A.2-2-3
-------
Appendix A.3: Saturated Flow; Numerical Models for Three-Dimensional Flow, Part 1: Model
Description
IGWMC Key: 510 Model Name: ISOQUOD Released: 1982
Authors: Finder, G.F., and E.G. Frind
ISOQUOD is a finite element model to simulate transient three-dimensional groundwater flow in anisotropic
and heterogeneous, confined or unconfined aquifers.
Contact Address: Water Resources Program, Department of Civil Engineering, Princeton University,
Princeton, NJ 08540
IGWMC Key: 770 Model Name: USGS-3D-FLOW Released: 1982
Authors: Trescott, P.C., S.P. Larson, and LJ, Torak.
USGS-3D-FLOW is a widely used, general purpose finite difference model to simulate transient,
three-dimensional and quasi-three-dimensional, saturated flow in anisotropic, heterogeneous (layered)
groundwater systems. The flow system can be fully confined or the uppermost zone can be a water-table
aquifer. The model simulates well discharge/recharge from any layer and recharge to the uppermost layer.
The 1982 update extended the program to simulations involving leaky rivers, evapotranspiration as a linear
function of depth to water, and discharge to drains and springs. (Replaced by MODFLOW).
Contact Address: L Torak, U.S. Geological Survey, Branch of Groundwater, M.S. 411 National
Center, Reston, VA 22092
IGWMC Key: 2072 Model Name: FE3DGW Released: 1985
Authors: Gupta, S.K., C.R. Cole, and F.W. Bond.
FE3DGW is a finite element model for transient or steady state, fully or quasi-three-dimensional simulation
of flow in a large multi-layered groundwater basin. The code offers a wide choice of in specifying boundary
conditions like prescribed heads, nodal injection or withdrawal, constant or spatially varying infiltration rates,
and elemental sources or sinks. Support programs are included to plot the finite element grid, contour maps
of input and output parameters, and vertical cross-sections. Also, there are support programs available for
determining groundwater pathlines and travel times from a specified point. (Also distributed as part of
CFEST).
Contact Address: Nat. Energy Software Ctr., Argonne Nat. Lab., 9700 S. Cass Ave, Argonne, IL 60439
IGWMC Key: 2090 Model Name: VTTSS3 Released: 1979
Authors: Reisenauer, A.E., C.R. Cole.
VTTSS3 (Variable Thickness Transient/Steady-State 3D model) is a finite difference model to predict
steady-state hydraulic head in unconfined or (leaky-) confined, isotropic, heterogeneous, multi-layered
aquifer systems. It can generate streamlines and traveltimes and has a separate module for cell-by-cell
calculation of the water budget. Solving the steady-state equations is done with the Newton method and
direct Gaussian elimination.
Contact Address: Cole, C.R., Battelle Pacific NW Laboratories, Water and Land Resources Div., P.O. Box
999, Richland, WA 99532
A.3-1-1
-------
Appendix A.3, part 1 (continued)
IGWMC Key: 2663 Model Name: Variable Density Model Released: 1984
Author: Kuiper, LK.
Kuiper's model is an integrated finite difference model for the simulation of variable density, time dependant
groundwater flow in three dimensions. The governing equation is the three-dimensional transient flow
equation with fresh water head as dependent variable. The groundwater density, although variable in space,
is approximately constant in time and known. The IFDM grid elements are rectangular when viewed from
the vertical direction, but their top and bottom surfaces follow the curvature of the geologic strata. Solution
methods employed are the line successive over-relaxation method, the strongly implicit procedure, and a
conjugate gradient method.
Contact Address: Kuiper, L.K., U.S. Geological Survey, 211 East 7th Street, Austin, TX 78701
IGWMC Key: 2740 Model Name: NMFD-3D Released: 1980
Authors: Posson, D.R., G.A. Hearne, J.V. Tracy, and P.P. Frenzel
NMFD-3D (New Mexico Finite Difference 3-Dimensional Model) simulates non-steady state two-dimensional
horizontal or fully-three-dimensional groundwater flow in multi-layered heterogeneous, anisotropic aquifer
systems or three-dimensional saturated groundwater flow. The model includes an analytical-numerical
approximation for transient leakage from confining beds and allows for both confined and water table
conditions.
Contact Address: Posson, D.R., U.S. Geological Survey, P.O. Box 26659, Albuquerque, NM 87125
IGWMC Key: 2880 Model Name: GWHEAD Released: 1980
Authors: Beckmeyer, R.R., R.W. Root, and K.R. Routt
GWHEAD is a computer code for simulating transient three-dimensional groundwater flow in an anisotropic,
spatially heterogeneous aquifer. The model solves the finite difference approximations using the strongly
implicit solution procedure. The boundaries either may permit flow across them or may be impermeable.
The top boundary represents the water table and its location is a function of the dependent head variable.
Across this boundary the model allows vertical accretion (recharge). The code has been used to model
leaky confined groundwater conditions and spherical flow to a continuous point sink, both of which have
exact analytical solutions.
Contact Address: Code custodian, Waste Disposal Technology Division, E.I. du Pont de Nemours &
Co., Savannah River Lab., Aiken, SC 29808
IGWMC Key: 3863 Model Name: SEEP(VM)-3D Released: 1983
Author: Desai, C.S.
SEEP(VM)-3D simulates three-dimensional confined, and steady and transient free surface seepage in porous
bodies (dams, wells, slopes, drains, media with cracks) using a finite element technique with variable and
moving mesh.
Contact Address: Desai, C.S., Univ. of Arizona, Dept. of Civil Eng. and Mech. Eng., Tuscon, AZ 85721
A.3-1-2
-------
Appendix A.3, part 1 (continued)
IGWMC Key: 3980 Model Name: MODFLOW Released: 1988
Authors: McDonald, M.G., and A.W. Harbaugh.
MODFLOW is a widely-used, modular, block-centered finite difference model for the simulation of
two-dimensional and quasi- or fully-three-dimensional, transient groundwater flow in anisotropic,
heterogeneous, layered aquifer systems. It calculates piezometric head distributions, flow rates and water
balances. The model includes modules for flow towards wells, through riverbeds, and into drains. Other
modules handle evapotranspiration and recharge. Various textual and graphic pre- and postprocessors are
available. Additional simulation modules are made available by the authors and by third parties, including
PATH3D, MODPATH, MT3D, STR1, Interbed Storage Packkage, and ZONEBUDGET.
Contact Address: A.W. Harbaugh, U.S. Geological Survey, Groundwater Branch, WRD WGS - Mail
Stop 433, National Center, Reston, VA 22091
IGWMC Key: 3982 Model Name: PATH3D Released: 1990
Author: Zheng, C.
PATH3D is a general particle tracking program for calculating groundwater paths and travel times in transient
three-dimensional flow fields. The program includes two major segments: 1) a velocity interpolator which
converts hydraulic heads, as generated by the USGS three-dimensional modular flow model MODFLOW,
into a velocity field, and 2) a fourth-order Runge Kutta numerical solver with automatic time steps size
adjustment for tracking the movement of fluid particles.
Contact Address: C. Zheng, S.S. Papadopulos & Assoc., Inc., 7944 Wisconsin Avenue, Bethesda,
Maryland 20814
IGWMC Key: 4500 Model Name: FEM301 Released: 1985
Author: Kiraly, L.
FEM301 is a three-dimensional finite element model for simulation of steady state flow in an equivalent
anisotropic porous medium intersected by linear or planar discontinuities. These discontinuities may be thin
aquifers between aquitards or permeable shear zones. Such features are modeled with one- or
two-dimensional elements embedded in the three-dimensional network. Post-processing routines include
calculation and graphic display of pathlines and traveltimes within the three-dimensional network.
Contact Address: Hufschmied, P., Nat. Coop, for Storage of Radioactive Waste (NAGRA), Parkstrasse
23, CH-5401 Baden, Switzerland.
A.3-1-3
-------
Appendix A.3, part 1 (continued)
IGWMC Key: 4660 Model Name: FLOSA (FLOw Systems Analysis) Released: 1988
Authors: Zijl, W., and M. Nawalany
FLOSA is a series of finite element/finite difference models for simulation of two- and three-dimensional
steady-state groundwater flow in anisotropic, heterogeneous porous media. The models are based on the
use of flow velocity as dependent variable in the numerical solution. Separate programs exist for pathline
generation and travel times calculation.
Contact Address: W. Zijl, TNO Inst. for Applied Geoscience, P.O. Box 6012, 2600 JA Delft, The
Netherlands
IGWMC Key: 4940 Model Name: DYNFLOW Released: 1992
Authors: Riordan, P.J., R.P. Schreiber, and B.M. Harley.
DYNFLOW (DYNamic groundwater FLOW simulation model) is a Galerkin finite element model for the
simulation of transient and steady-state three-dimensional groundwater flow in multi-layered aquifer systems.
The model handles 2D area! and cross-sectional and fully-3D situations, induced infiltration from streams,
artificial and natural recharge or discharge, and heterogeneous, anisotropic aquifer hydraulic properties.
It solves both linear (confined) and nonlinear (unconfined) aquifer flow equations, including the transition
in time and/or space from confined to unconfined. The program has a "rising water" scheme to allow
drainage to local streams if the piezometric head in a phreatic aquifer rises to the elevation of the stream
bed. DYNFLOW has the following optional solvers: (1) gauss elimination, (2) successive overrelaxation with
or without preconditioning, and (3) conjugate gradient with preconditioning.
DYNFLOW is part of DYN-SYSTEM, an integrated set of ground-water modeling programs used within the
COM company. Other components of the system are: DYNSWIM: 3-D sea water intrusion model; DYNAPL:
3-D two-phase (sharp interface) model; DYNPOTS: 3-D potential flow theory model; DYNCON: 3-D finite
element mass transport model; DYN-EDM: environmental data manager. The DYN-SYSTEM includes various
support programs and a model parameter optimization program.
Contact Address: B.M. Harley, Camp Dresser & McKee Inc., One Cambridge Center, Cambridge, MA
02142
IGWMC Key: 5560 Model Name: 3-D Free Surface FE Model Released: 1985
Authors: Durbin, T.J., and C. Berenbroeck.
This model utilizes the Galerkin finite element method for solving the equation of three-dimensional
ground-water flow through a multi-aquifer system. The model handles deformation of the grid resulting
caused by geometric changes of the ground-water system resulting from vertical movement of the water
table during transient-state simulations. The three-dimensional grid is assembled from stacks of prismatic
elements in each of which three tetrahedrons are fitted. This allows, among others, for layer pinch-outs.
The model can handle a free-surface boundary at the top of the aquifer, prescribed hydraulic head and
(zero) flux boundaries.
Contact Address: T.J. Durbin, U.S. Geological Survey, Federal Building, Room W-2234, 2800 Cottage
Way, Sacramento, CA 95825
A.3-1-4
-------
Appendix A.3, part 1 (continued)
IGWMC Key: 5600 Model Name: STLINE Released: 1990
Authors: -
STLINE is a 3D particle tracking program using intercell flow rates computed by a finite difference model.
The specific discharge vectors are converted to average linear flow velocities. Particle movements within
the velocity field are computed by a linear interpolation scheme using a local coordinate system embedded
in the global coordinate system of the numerical model. Intracell-particle translations and traveltimes are
based on a linear variation in velocities in the cell. The trajectory of each particle is stored in memory as
a series of particle translations each with a specific and accumulated travel time within the global coordinate
system. Particle trajectories can be displayed in each of the three orthogonal planes of the Cartesian
coordinate system.
Contact Address: D. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite #100, Sterling, VA 22170
Note: See also Appendix C.3; some 3-D solute transport models include a sophisticated flow simulation
module.
A.3-1-5
-------
Appendix A.3: Saturated Flow; Numerical Models for Three-Dimensional Flow, Part 2: Usability and Reliability
IGWMC
Key
510
770
2072
2090
2663
2740
2880
3863
3980
3982
4500
4660
4990
5560
5600
Model
ISOQUAD
USGS-3D-FLOW
FE3DGW
VTTSS3
Variable Density
Model
NMFD-3D
GWHEAD
SEEP(VM)-3D
MODFLOW
PATH3D
FEM301
FLOSA
DYNFLOW
3-D Free Surface
FE Model
STLINE
Usability
5
o
10
a.
£
N
N
Y
N
N
N
N
N
Y
Y
Y
Y
Y
N
Y
Postprocessor
N
N
Y
N
N
N
N
N
Y
Y
Y
Y
Y
N
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
Y
N
N
N
N
U
Y
Y
Y
Y
Y
N
Y
Support
N
N
N
N
N
N
N
U
N
Y
N
Y
Y
N
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
Y
Y
U
U
U
U
U
Y
U
U
U
Y
U
U
Verified
U
E
E
L
L
L
L
L
E
L
L
L
E
L
L
Field Tested
U
Y
Y
U
U
U
U
U
Y
Y
Y
U
Y
U
U
£
a
^
•a
o
5
U
M
M
F
F
F
F
F
M
M
F
F
M
F
F
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
A.3-2-1
-------
Appendix A.4: Saturated Flow; Analytical Inverse Models (Aquifer Test Models), Part 1: Model
Description
IGWMC Key: 2801 Model Name: SATEM Released: 1989
Author: Boonstra, J.
SATEM (Selected Aquifer Test Evaluation Methods) is a set of four interactive microcomputer programs for
analysis of aquifer tests in unconsolidated, confined, leaky confined or phreatic aquifers. These programs
are: JACOB, HANTUSH, PARTIAL, and RECOVERY. For aquifers under fully confined or unconfined
conditions SATEM allows for partial penetrating wells. The program has been designed to provide quick
evaluation of the field data by using diagnostic plots, a method well-suited for sensitivity analysis. It can
evaluate the drawdown data observed during pumping and residual drawdown data observed during
recovery. The field data can be taken from observation and/or from the pumping well itself. SATEM
includes a program for inputting field data and a program to set up hypothetical single well aquifer test data
for instructional purposes.
Contact Address: J. Boonstra, Internal. Inst. for Land Reclamation and Improvement, P.O. Box 45,
6700 AA Wageningen, The Netherlands
IGWMC Key: 3150 Model Name: HVRLV1 Released: 1981
Authors: Weyer, K.U., and W.C. Horwood-Brown
HVRLV 1 is an interactive, user-oriented calculation of permeabilities from slug tests using Hvorslev's
formulae for filters in uniform soil.
Contact Address: K.U. Weyer, Nat. Hydrology Research Inst., Ground Water Division, 101-4616
Valiant Drive N.W., Calgary, Alberta Canada, T3A OXG
IGWMC Key: 4751 Model Name: AQ-AT Released: 1989
Authors: Kovar, K., and A. Leijnse
AQ-AT is a computer program package for aquifer test analysis due to pumpage in a homogeneous infinite
multi-layered aquifer-aquitard system. The menu-driven package includes modules for confined and
leaky-confined systems and provides the best estimate for aquifer and aquitard parameters and
corresponding uncertainty using least squares optimization. The program includes help screens and error
checking. It has options for joint graphic display of observed drawdowns (input) and computed drawdowns
using the estimated parameters.
Contact Address: K. Kovar, Inst. of Public Health and Environm. Protection, P.O. Box, 3720 BA
Bilthoven, The Netherlands
IGWMC Key: 5002 Model Name: MATE Released: 1985
Author: Hemker, C.J.
MATE (Microcomputer Aquifer Test Evaluation) is menu-driven, user-interactive program to evaluate aquifer
parameters (transmissivity, storage coefficient, leakance) from pumping test data using the least-squares
approach together with the Malquardt algorithm. The program can handle four types of aquifer parameter
evaluations including: 1) steady-state flow in semi-confined aquifers (De Glee); 2) unsteady-state flow in
(semi-)confined aquifers (Theis or Hantush well function); 3) recovery test in (semi-)confined aquifers (Theis
or Hantush well function); and steady-state flow in multiple aquifer systems (Hemker).
Contact Address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
A.4-1-1
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 5003 Model Name: MLU (Multi-Layer Unsteady-state model) Released: 1986
Author: Hemker, C.J.
MLU is a program for drawdown calculations and inverse modeling (aquifer tests) of transient flow in layered
(up to 9 aquifers) and fissured (double porosity aquifer systems) under (semi-)confined and unconfined
conditions. The model is based on a series of analytical solutions.
Contact Address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
IGWMC Key: 5040 Model Name: GWAP Released: 1989
Author: Dansby, D.A.
GWAP (Graphical Well Analysis Package) is a well test analysis package that provides a computer-based
method of performing graphical curve matching. Data from the well test are plotted on the computer screen
and then a type curve is selected, overlain, and matched to the data directly on the screen. GWAP supports
confined-leaky aquifer (Hantush, 1956), unconfined aquifer (Neuman, 1975), large diameter well
(Papadopulos and Cooper, 1967), and slug injection/withdrawal (Cooper et al., 1967) type curves.
Contact Address: Groundwater Graphics, 5209 Windmill Str., Oceanside, CA 92506
IGWMC Key: 5050 Model Name: HJ-MATCH Released: -
Author: Bump, A.C., and M.S. Ramesh
HJ-MATCH is an aquifer characterization program for fully penetrated, leaky, confined aquifers. HJ-MATCH
computes the best values of aquifer transmissivity (permeability), storage coefficient (porosity-compressibility
factor), aquitard hydraulic conductivity, and leakage factor in user-selected hydrology or petroleum
terminology. The best values are determined automatically by matching pumping test data with families of
type curves using non-linear relative least-squares matching. Completely automated, HJ-MATCH does not
require initial estimates of hydrologic parameters. The program uses the Papadopulos method when
drawdown data for at least three observation wells are available. The user-interactive program includes
graphic output to screen, plotter, or printer.
Contact Address: In-Situ, Inc., P.O. Box 1, Laramie, Wyoming 82070
IGWMC Key: 5051 Model Name: PAPADOP Released: -
Authors: -
PAPADOP is an aquifer characterization program that calculates directional transmissivities (permeabilities)
and frequency of direction of major transmissivity (permeability). The program uses multiwell test data to
obtain directional transmissivity and storage coefficient in hydrologic units or directional permeability and
porosity-compressibility factor in petroleum terminology. A method modified from the well-known
Papadopulos method is used. The directional properties are computed for all three observation well
combinations possible (up to 100 observation wells). The program can be used with almost any aquifer and
well conditions (leaky or non-leaky, unconfined or confined, fractured, partially or fully penetrated).
Contact Address: In-Situ, Inc., P.O. Box 1, Laramie, Wyoming 82070
A. 4-1-2
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 5052 Model Name: STEP-MATCH Released: -
Authors: Bumb, A.C., and M.S. Ramesh
STEP-MATCH automates the processing and analysis of data from slug tests. The program plots field data
in semilog form; calculates type curves representing various wellbore storage, skin and transmissivity values,
and determines the "best" match using non-linear least squares and Taylor series approximation. The
program includes a menu-driven, full screen editor environment and supports additional graphic programs
available from the same vendor.
Contact Address: In-Situ, Inc., P.O. Box 1, Laramie, Wyoming 82070
IGWMC Key: 5054 Model Name: TS-MATCH Released: ~
Authors: -
TS-MATCH is an aquifer characterization program for fully penetrated, non-leaky, confined aquifers. It
computes the best values for transmissivity and storage coefficient or permeability and
porosity-compressibility factor by matching the Theis exponential integral type curve with field pump test
data. TS-MATCH uses full type-curve and non-linear relative least-squares matching. The program can
compute directional transmissivities or permeabilities using the Papadopulos method when data from at least
three observation wells are available.
Contact Address: In-Situ, Inc., P.O. Box 1, Laramie, Wyoming 82070
IGWMC Key: 5060 Model Name: PTDPSI Released: -
Author: Blair, A.W.
PTDPS I is a pumping test data plotting software for use with confined aquifers. It performs the following
functions: (1) Cooper/Jacob confined aquifer trend, drawdown, and recovery graphs; (2) Thiem
test-distance/drawdown analysis and trend and drawdown graphs; (3) Theis equation match point method
trend and drawdown graphs; (4) step drawdown test trend and step drawdown graphs; (5) well and
formation losses; (6) transmissivity and storage coefficient calculations; and (7) least squares or manual
interactive graphic curve fitting.
Contact Address: A.W. Blair, IRRISCO, P.O. Box 5011, University Park, New Mexico 88003
IGWMC Key: 5061 Model Name: PTDPS II Released: --
Author: Blair, A.W.
PTDPS II is a pumping test data plotting software for use with unconfined/leaky aquifers with the following
functions: (1) Cooper/Jacob unconfined aquifer trend, drawdown graphs; (2) Hvorslev slug (falling head)
and bail (rising head) piezometer tests; (3) Hantush/Jacob leaky aquifer match point method trend and
drawdown graphs; (4) transmissivity and storage coefficient calculated using least squares or manual
interactive graphic curve fitting.
Contact Address: A.W. Blair, IRRISCO, P.O. Box 5011, University Park, New Mexico 88003
A.4-1-3
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 5062 Model Name: PTDPS III Released: --
Author: Blair, A.W.
PTDPS III is a pumping test data plotting software for confined, leaky confined and unconfined aquifers.
For confined aquifers the software performs the following functions: (1) Cooper/Jacob semilog method; (2)
Theis well function match point method; and (3) Thiem distance/drawdown method. With unconfined
aquifers the program handles the Cooper/Jacob semilog method. With leaky confined aquifers the program
includes the Hantush/Jacob method. The program also performs: (1) step drawdown well/formation loss
method; (2) Hvorslev's bail test method and slug test method; and (3) Bouwer and Rice piezometer
functions.
Contact Address: A.W. Blair, IRRISCO, P.O. Box 5011, University Park, New Mexico 68003
IGWMC Key: 5070 Model Name: PUMPING TEST PROGRAM Released: -
Authors: -
This is a pumping test program package for analysis of drawdown and recovery tests. Hydrographs and
site plans can be plotted and step tests analyzed. The programs will take the data from manual input or
data loggers and will correct them for partial penetration or water table conditions. The aquifer coefficients
can be calculated using straight line or least squares fit. It is possible to use only part of the graph for
analysis.
Contact Address: Earthware of California, 30100 Town Center Drive, #196, Laguna Niguel, CA 92677
IGWMC Key: 5080 Model Name: PUMP Released:-
Author: Ulrick, J.
The Theis method pumping test analysis program PUMP matches a Theis curve to selected aquifer
drawdown and recovery test data by Gauss-Newton non-linear regression. For a pumping well, corrections
may be made for casing storage, water-table conditions, and well loss. The program is menu, driven and
has full screen editing capabilities. Various options are available for graphic display and plotting of the
results.
Contact Address: Ulrick & Associates, 1400 Grandview Drive, Berkeley, CA 94705
IGWMC Key: 5090 Model Name: WHIP Released: -
Authors: -
WHIP (Well Hydraulics Interpretation Program) is a menu driven interactive program which allows the user
to design and interpret complex aquifer tests. The program handles simulation and analysis of aquifer tests
with multiple pumping wells, time-varying pumping rates, and realistic pumped well conditions. WHIP uses
numerical Laplace inversion techniques to solve the analytical equations of drawdown in homogeneous,
vertically anisotropic, or double porosity aquifers.
Contact Address: G. Walter, Hydro Geo Chem Inc., 1430 N. 6th Avenue, Tuscon, AZ 85705
A.4-1-4
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 5190 Model Name: PUMPING TEST PACKAGE Released:--
Authors: -
The PUMPING TEST PACKAGE calculates optimal values of aquifer parameters as transmissivity, storage
coefficient, leakage coefficient, and hydraulic resistance from pumping test data as observed on one or more
wells (up to 10 wells). The menu-driven program uses a non-linear regression technique and provides for
error checking in input.
Contact Address: Rockware, Inc., 4251 Kipling Street, #595, Wheatridge, CO 80033
IGWMC Key: 5460 Model Name: Groundwater Discharge Tests Released: 1988
Author: Clarke, D.
This software is a menu-driven series of programs for designing and analyzing aquifer tests, ft includes the
following modules: (1) DTDHA - Discharge Test Data Handling and Analysis; this module uses the modified
Sternberg and the Rorabaugh analysis for step-drawdown and recovery; (2) DRAWDOWN - drawdown in
bounded or unbounded (leaky) confined aquifers using the Theis well function or the leaky confined aquifer
well function; (3) NEUMAN - drawdown in an unconfined aquifer using Neuman's well function; (4) ANALYZE
- determining transmissivity and storage coefficient for a (leaky) confined aquifer using least squares; and
(5) various file manipulation and plotting utilities.
Contact Address: Clarke Computer Services, 20 Musgrave St., Crystal Brook, 5523, Australia
IGWMC Key: 6025 Model Name: THCVFIT Released: 1992
Author: van der Heijde, P.K.M.
THCVFIT is an interactive program to determine transmissivity and storage coefficient from pump test data.
This model replaces traditional curve-fitting by a graphics routine to match the Theis well function with field
drawdown data. Match point and resulting parameters are listed.
Contact Address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6080 Model Name: THEISFIT Released: 1991
Author: McElwee, C.D.
THEISFIT is a non-graphic, interactive program that calculates aquifer parameters by automatically fitting
type curve and pump test data from pumping an isotropic heterogeneous nonleaky confined aquifer using
a least squares method. The program has been designed to analyze data conforming to assumptions
implicit in the Theis equation.
Contact Address: C.D. McElwee, Kansas Geological Survey, 1930 Avenue A, Campus West, University
of Kansas, Lawrence, KS 66044, or Internat. Ground Water Modeling Ctr.
A.4-1-5
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 6081 Model Name: TSSLEAK Released: 1992
Authors: Cobb, P.M., C.D. McElwee, and M.A. Butt
TSSLEAK is an interactive program for automated analysis of pumping-test data for a leaky-confined aquifer
using a least-squares procedure for fitting the Hantush and Jacob equation to experimental time-drawdown
data to obtain estimates for storage coefficient, transmissivity, leakage coefficient, and aquitard permeability.
The program prompts for user-input and provides the results in ASCII text files.
Contact Address: C.D. McElwee, Kansas Geological Survey, 1930 Avenue A, Campus W, University
of Kansas, Lawrence, KS 66044, or Internal. Ground Water Modeling Ctr.
IGWMC Key: 6082 Model Name: VARQ Released: 1987
Authors: Butt, M.A., and C.D. McElwee
VARQ is an interactive program to calculate aquifer parameters by automatically fitting pump test data with
a Theis-type curve. It evaluates transmissivity and storage coefficient for a homogeneous, isotropic confined
aquifer using a least-squares procedure. The program allows for variable discharge rates during the test.
As a measure of error, the rms (root-mean-square) error in drawdown is calculated along with the correlation
coefficient between pumping-test data and theoretically generated data, using the converged values of
transmissivity and storage coefficient. Output is in tabular form.
Contact Address: C.D. McElwee, Kansas Geological Survey, 1930 Avenue A, Campus West, University
of Kansas, Lawrence, KS 66044, or Internat. Ground Water Modeling Ctr.
IGWMC Key: 6382 Model Name: PUMPTEST Released: 1992
Author: Beljin, M.S.
PUMPTEST is an interactive program designed to determine aquifer parameters by analyzing aquifer test
data using a least-squares fitting procedure. The package includes a program to evaluate transmissivity and
storage coefficient based on Jacob's straight line method, a program to estimate transmissivity and storage
coefficient from distance-drawdown data, and a program to estimate transmissivity from time-residual
drawdown aquifer test data. Results are presented graphically and in ASCII format.
Contact Address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6450 Model Name: TGUESS Released: 1985
Authors: Bradbury, K.R., and E.R. Rothchild
TGUESS is a simple interactive program for estimating transmissivity from specific capacity data. The
program corrects for partial penetration and well loss. Output is in ASCII format.
Contact Address: K.R. Bradbury, Wisconsin Geological Survey, 1815 University Ave., Madison, Wl
53705, or Internat. Ground Water Modeling Ctr.
A.4-1-6
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 6580 Model Name: TIME LAG Released: 1987
Author: Thompson, D.B.
TIMELAG is an interactive program for evaluating permeability from single well tests based on the rate of
water-level recovery after raising or lowering the water level in a well. Output is in ASCII format.
Contact Address: D. Thompson, SRW Associates, Inc., Robinson Plaza II, Suite 200, Pittsburgh, PA
15205, or Internal. Ground Water Modeling Ctr.
IGWMC Key: 6670 Model Name: AQTESOLV Released: 1992
Authors: --
AQTESOLV (AQuifer TEst SOLVer) is a user-friendly software package designed to assist in the analysis of
pumping tests and slug tests. It computes and plots type curves for a number of different analytical
solutions. The program allows the user to visually fit a type curve to time-drawdown data or provides
least-squares based automatic estimation of aquifer properties. The options for constant-rate pumping tests
include: (1) Theis, Cooper-Jacob and Theis recovery for confined aquifers; (2) Hantush for leaky aquifers;
(3) Neuman, Theis and Cooper-Jacob for unconfined aquifers; and (4) Moench for fractured aquifers. For
slug tests in confined aquifers the program provides the Cooper-Bredehoeft-Papadopulos method and for
unconfined aquifers the Bouwer-Rice method.
Contact Address: Geraghty & Miller Modeling Group, 10700 Park Ridge Blvd, Suite 600, Reston, VA
22091
IGWMC Key: 6680 Model Name: SLUGIX/AQUIX-S Released: 1992
Authors: -
SLUGIX or AQUIX-S is an interactive, forward and inverse modeling program for analyzing slug test data.
In the forward mode it provides the head response for a slug test for given aquifer storativity and
transmissivity or hydraulic conductivity. The solution method of the inverse model is based on a non-linear
least-squares fitting of the Cooper, Bredehoeft and Papadopulos model for a confined aquifer. The Bouwer
and Rice model for an unconfined fully or partially penetrated aquifer and the Hvorslev models for a well
point filter in uniform soil or at an impervious boundary use a real-time, interactive graphical curve fitting
approach. The model comes with a sophisticated textual and graphic user-interface and report facilities.
Contact Address: T. Gilmer, EnviroTools Ltd, 27203 Armadillo Way, Evergreen, CO 80439
IGWMC Key: 6681 Model Name: AQUIX-T/AQUIX-4 Released: 1992
Authors: -
AQUIX-4 is a series of programs for the interactive, forward and inverse modeling of pumping test data with
constant or variable flow rates and full recovery analysis. It provides drawdowns in terms of aquifer
storativity, transmissivity, leakage, anisotropy, and specific yield, depending on the model selected. A least
squares, nonlinear curve fitting method is used to determine the best fit model parameters to the observed
data. AQUIX include programs for partial penetrating wells, and for confined, leaky confined and unconfined
aquifers. The models are based on Theis (1935), Hantush (1960, 1965), and Neuman (1975). The model
comes with a sophisticated textual and graphic user-interface and report facilities. AQUIX-T includes only
the Theis varying rate recovery mode.
Contact Address: T. Gilmer, EnviroTools Ltd., 27203 Armadillo Way, Evergreen, CO 80439
A.4-1-7
-------
Appendix A.4, part 1 (continued)
IGWMC Key: 6730 Model Name: TENSOR2D Released: 1987
Authors: Maslia, M.L, and R.B. Randolph
TENSOR2D is a program for computing the components of the anisotropic transmissivity tensor of
two-dimensional groundwater flow. To determine the tensor components using one pumping well and three
observation wells, the type-curve and straight-line approximation methods are used. To determine the tensor
components using more than three observation wells a weighted least-squares optimization method is used.
Contact Address: U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box
25425, Denver, CO 80225
A.4-1-8
-------
Appendix A.4: Saturated Flow; Analytical Inverse Models (Aquifer Test Models), Part 2: Usability and
Reliability
IGWMC
Key
2801
3150
4751
5002
5003
5040
5050
5051
5052
5054
5060
5061
5062
5070
5080
5090
5190
5460
6025
6080
Model
SATEM
HVRLV 1
AQ-AT
MATE
MLU
GWAP
HJ-MATCH
PAPADOP
STEP-MATCH
TS-MATCH
PTDPS I
PTDPS II
PTDPS III
PUMPING TEST
PROGRAM
PUMP
WHIP
PUMPING TEST
PACKAGE
GROUND WATER
DISCHARGE
TESTS
THCVFIT
THEISFIT
Usability
Preprocessor
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Postprocessor
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Problems
0.
W
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
ire Dependency
4
X
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
o
a
a
(0
L
N
Y
L
L
Y
Y
Y
Y
Y
Y
Y
Y
Y
L
Y
Y
L
L
L
Reliability
viewed Theory
K
w
0
Q.
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
iviewed Coding
a.
«
Ot
N
N
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
N
N
•u
iS
•c
>
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
•o
e
-------
Appendix A.4, part 2 (continued)
IGWMC
Key
6081
6082
6382
6450
6580
6670
6680
6681
6730
Model
TSSLEAK
VARQ
PUMPTEST
TGUESS
TIMELAG
AQTESOLV
SLUGIX/AQUIX-S
AQUIX-T/
AQUIX-4
TENSOR2D
Usability
o
u
(0
u
0
Q.
01
CL
Y
Y
Y
Y
Y
Y
Y
Y
N
t
10
10
?,
o
0
a
N
N
Y
N
N
Y
Y
Y
N
a
O
"ft
U
c
(0
u
Y
Y
Y
Y
Y
Y
Y
Y
Y
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A.4-2-2
-------
Appendix A.5: Saturated Flow; Numerical Inverse Models, Part 1: Model Description
IGWMC Key: 195 Model Name: NON-LINEAR FE/FD REGRESSION Released: 1985
Authors: Cooley, R.L., and R.L Naff
An interactive, inverse groundwater flow model using non-linear regression and finite-element or (integrated)
finite-difference simulation. It estimates areally distributed discharge and recharge, boundary fluxes and
heads, vertical hydraulic conductance, and transmissivity distribution based on best fit hydraulic head
distribution for steady state, horizontal groundwater flow in an anisotropic, heterogeneous aquifer. The
regression is based on steady-state observed heads, prior estimates of the regression parameters and their
reliability, and known fluxes into or out of the aquifer. Various statistics associated with the regression
analysis are computed.
Contact Address: Cooley, R.L, U.S. Geol. Survey, m.s. 413, Federal Center, Denver, CO 80225
IGWMC Key: 3981 Model Name: MODINV Released: 1990
Authors: Doherty, J., R.E. Volker, and R.G. Pearson
MODINV (MODFLOW Parameter Optimization) is a parameter optimization program based on the USGS
three-dimensional modular flow model MODFLOW. it accepts a wide variety of MODFLOW parameters for
optimization, including recharge rates, hydraulic conductivity, transmissivity, EVT extinction depth, etc. The
program requires preliminary parameters zoning and is based on the matching of calculated and observed
heads according to a weighted least squares criterion. Optimization is achieved using the Gauss-Marquardt
method. The program comes with a forward simulation version of MODFLOW and pre- and postprocessors
including a mesh generation routine.
Contact Address: J. Doherty, Australian Centre for Tropical Freshwater Research, James Cook
University, Townsville, Old 4811, Australia
IGWMC Key: 3987 Model Name: MODFLOWP Released: 1992
Author: Hill, M.C.
MODFLOWP is a new version of the USGS modular, 3-D finite difference flow model MODFLOW
incorporating the new Parameter-Estimation Package. The model can be used to estimate various
MODFLOW parameters by nonlinear regression. Parameters are estimated by minimizing a weighted
least-squares objective function by the modified Gauss-Newton method or by a conjugate direction method.
Any spatial variation in parameters can be defined by the user. Data used to estimate parameters can
include existing independent estimates of parameter values, observed hydraulic heads or temporal changes
in heads, and observed gains and losses along head-dependent boundaries. The performance of the code
has been tested in models of both actual and hypothetical groundwater systems (see also remarks).
Contact Address: M.C. Hill, U.S. Geological Survey, Water Resources Division, Box 25046, M.S. 413,
Denver Federal Center, Denver, CO 80225
Note: There are many more codes written for parameter estimation using numerical approximation of the
governing equations and direct or indirect techniques to solve the inverse problem. Most of these
codes are experimental and considered "research codes." In general they are not readily available.
A.5-1-1
-------
Appendix A.5: Saturated Flow; Numerical Inverse Models, Part 2: Usability and Reliability
IGWMC
Key
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3981
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A.5-2-1
-------
Appendix A.6: Saturated Flow; Pathline Models, Part 1: Model Description
IGWMC Key: 741 Model Name: USGS FRONT-TRACKING Released: 1983
Authors: Garabedian, S.P., Konikow, LF.
USGS FRONT-TRACKING is a finite difference model for simulation of advective transport of a conservative
tracer dissolved in groundwater under steady or transient flow conditions. The model calculates heads,
velocities and tracer particle positions.
Contact Address: LF. Konikow, U.S. Geological Survey, Water Resourc. Div., 431 National Center,
Reston, VA 22092
IGWMC Key: 1791 Model Name: SLAEM/SLW/SLWL/SYLENS Release: 1992
Author: Strack, O.D.L., et al.
SLAEM and its predecessor SYLENS are models for analysis of two- and three-dimensional steady-state and
transient groundwater flow in single or multi-layered aquifer systems based on the Analytical Element
Method. SLAEM is an highly interactive graphic oriented program including many of the analytical elements
available. The program includes transient wells, areal inhomogeneities, leaky or draining objects, variable
infiltration (e.g. from rivers, lakes, and ponds). It allows analysis of flow in two aquifers separated by a thin
confining layer. The model is especially suited to analyze flow in regional double aquifer systems with local
interconnections. SLW and SLWL are scaled-down, educational versions of the SLAEM program.
Contact Address: O.D.L Strack, Univ. of Minnesota, Dept. of Civil Eng., 122 CME Building,
Minneapolis, MN 55455
IGWMC Key: 1820 Model Name: FLOP/FLOP-LIESTE/FLOP-Z1/FLOP-2N Released: 1988
Authors: Akker, C. Van Den, Lieste, R., Veling, E.J.M.
The FLOP models are semi-analytical models for calculation of pathlines and residence times in groundwater
systems. FLOP-LIESTE is designed for single (semi-) confined aquifers; FLOP-21 for a quasi
three-dimensional semi-confined aquifer system; and FLOP-ZN for a multi-layered homogeneous aquifer
system.
Contact Address: RIVM - National Institute for Health and Environment, P.O. Box 1, 3720 AB
Bilthoven, The Netherlands
IGWMC Key: 1822 Model Name: FRONT Released: 1981
Author: Akker, C. Van Den
FRONT is a semi-analytical model for calculation of pathlines and residence times in a confined, isotropic,
heterogeneous aquifer with steady-state or transient flow. The integration along the streamlines is performed
with Runge-Kutta, restricting the maximum time step size with a user-provided error-criterion.
Contact Address: RIVM - Nat. Inst. for Health and Environment, P.O. Box 1, 3720 BA Bilthoven, The
Netherlands
A.6-1-1
-------
Appendix A.6, part 1 (continued)
IGWMC Key: 2072 Model Name: FE3DGW Released: 1983
Authors: Gupta, S.K., Cole, C.R., Bond, F.W.
FE3DGW is a finite element model for transient or steady state, fully or quasi-three-dimensional simulation
of flow in a large multi-layered groundwater basin. The code offers a wide choice of in specifying boundary
conditions like prescribed heads, nodal injection or withdrawal, constant or spatially varying infiltration rates,
and elemental sources or sinks. Support programs are included to plot the finite element grid, contour maps
of input and output parameters, and vertical cross-sections. Also, there are support programs available for
determining groundwater pathlines and travel times from a specified point.
Contact Address: Nat. Energy Software Ctr./US DOE, Argonne Nat. Lab., 9700 S. Cass Ave, Argonne,
IL 60439 (also included in CFEST code)
IGWMC Key: 2092 Model Name: VTT Released: 1979
Authors: Reisenauer, A.E., Cole, C.R.
VTT (Variable Thickness Transient Groundwater Flow Model) is a finite difference model to calculate transient
hydraulic head in confined or unconfined isotropic, heterogeneous, multi-layered aquifer systems. The
model can calculate cell-by-cell water budgets and can generate stream-lines and travel times. Boundary
conditions and aquifer stresses may be time-varying. The transient model is solved with the line successive
over-relaxation method (LSOR).
Contact Address: Cole, C.R., Battelle Pacific NW Lab., Water and Land Resources Division, P.O. Box
999. Richland, WA 99352
IGWMC Key: 2120 Model Name: PATHS Released: 1980
Authors: Nelson, R.W., Schur, J.A.
The PATHS program is an idealized hybrid analytical/numerical model for simulation of steady-state or
transient, two-dimensional, saturated groundwater flow and transport processes of advection, sorption and
ion exchange. It includes an analytical solution of the flow equation and the Runge-Kutta solution for the
pathline equations and the effects of equilibrium ion-exchange and linear adsorption. The model calculates
pathlines, location/arrival time distribution, and location/outflow quantity distribution in a confined stratum
that is isotropic and homogeneous. It assumes a uniform lateral flow gradient and superimposed leakage
from a vertical, cylindrical fully penetrating pond or cavern. The model can handle up to 35 fully penetrating
wells or vertical line sources.
Contact Address: Battelle Pacific NW Laboratories, Land and Water Resources Div., P.O. Box 999,
Richland. WA 99352
IGWMC Key: 2770 Model Name: CONFLOW Released: 1981
Author: Hertel, E.S., Jr.
CONFLOW describes fluid flow between two wells in a confined homogeneous, isotropic region. The code
uses superposition to solve Laplace's equation with impermeable boundaries and can assist in the design
of flow experiments in geologic media. CONFLOW's output is a plot of the theoretical streamlines, the ratio
between the time of first arrival for the confined region and the time of first arrival for unconfined two-well
flow, and a value for the pressure drop function.
Contact Address: Hertel, E.S., Jr., Sandia Nat. Lab., Albuquerque, NM 87185
A.6-1-2
-------
Appendix A.6, part 1 (continued)
IGWMC Key: 3940 Model Name: RESSQ Released: 1985
Authors: Javandel, I., Doughty, C., Tsang, C.F.
RESSQ is a semi-analytical model of 2-dimensional contaminant transport that calculates the streamline
pattern in an aquifer, the location of contaminant fronts around sources at specified times, and concentration
versus time at sinks. RESSQ assumes a homogeneous, isotropic confined aquifer of uniform thickness and
a steady-state regional flow field. It can handle advection and linear equilibrium adsorption. Sources are
represented by fully penetrating recharge wells and ponds, and sinks are represented by fully penetrating
pumping wells.
Contact Address: Javandel, I., Lawrence Berkeley Lab., Earth Sciences Div., Univ. of California,
Berkeley. CA 94720
IGWMC Key: 3943 Model Name: WHPA Released: 1992
Authors: Blandford, T.N., Huyakorn, P.S.
WHPA (Well Head Protection Area delineation model) is an integrated program of analytical and
semi-analytical solutions for the groundwater flow equation coupled with pathline tracking. It is designed
to assist technical staff with delineation of wellhead protection areas. Developed for the U.S. EPA's Office
of Groundwater Protection, the package includes modules for capture zone delineation in a homogeneous
aquifer with 2-dimensional steady-state flow with options for multiple pumping/injection wells and barrier or
stream boundary conditions. Also included are modules for Monte Carlo analysis of uncertainty and a
particle-tracking postprocessor for numerical flow models such as MODFLOW and PLASM, using a
two-dimensional rectangular grid.
Contact Address: U.S. EPA, Off. of Groundwater Protection, Washington, D.C., or Internat. Ground
Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 3982 Model Name: PATH3D Released: 1990
Author: Zheng, C.
PATH3D is a general particle tracking program for calculating groundwater paths and travel times in transient
three-dimensional flow fields. The program includes two major segments: 1) a velocity interpolator which
converts hydraulic heads, as generated by the USGS three-dimensional modular flow model MODFLOW,
into a velocity field, and 2) a fourth-order Runge Kutta numerical solver with automatic time steps size
adjustment for tracking the movement of fluid particles.
Contact Address: C. Zheng, S.S. Papadopulos & Assoc., Inc., 7944 Wisconsin Ave, Bethesda, MD
20814
IGWMC Key: 3984 Model Name: MODPATH Released: 1988
Author: Pollock, D.W.
MODPATH is a post-processing package to compute three-dimensional path lines based on the output from
steady-state simulations obtained with the USGS MODFLOW groundwater flow model. The package
consists of two FORTRAN 77 computer programs: 1) MODPATH, which calculates pathlines, and 2)
MODPATH-PLOT, which presents results graphically. MODPATH uses a semi-analytical particle tracking
scheme, based on the assumption that each directional velocity component varies linearly within a grid cell
in its own coordinate direction. Data is input to MODPATH through a combination of files and interactive
dialogue.
continued
A.6-1-3
-------
Appendix A.6, part 1 (continued)
MODPATH - continued
The MODPATH-PLOT program comes in two versions, one for use with the DISSPLA graphics routines
library, and one that uses the Graphical Kernel System (GKS).
Contact Address: U.S. Geological Survey, Water Resources Division, 411 National Center, Reston, VA
22092; Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO
80401; or Scientific Software, Washington, D.C.
IGWMC Key: 4591 Model Name: MAGNUM-3D Released: 1985
Authors: Estey, S.A., Arnett, R.C., Aichele, D.R.
MAGNUM-3D is a three-dimensional finite element code for simulation of steady-state and transient
groundwater flow. The model can handle complex anisotropic, heterogeneous hydrologic systems.
Quadratic elements allow the user to model irregular boundaries and hydrogeologic structures in detail.
Layer pinch-outs can be modeled using three-dimensional prism elements. Stress may be applied in the
form of surface recharge due to precipitation or irrigation well discharge.
Contact Address: Sandra Estay or Deborah Aichele, BCS Richland, Inc., Richland, Washington 99352
IGWMC Key: 4660 Model Name: FLOSA Released: 1988
Authors: Zijl, W., Nawalany, M.
FLOSA (FLOw Systems Analysis) is a series of finite element/finite difference models for simulation of two-
and three-dimensional steady-state groundwater flow in anisotropic, heterogeneous porous media. The
models are based on the use of flow velocity as dependent variable in the numerical solution. Separate
programs exist for pathline generation and travel times calculation.
Contact Address: W. Zijl, TNO Inst. for Applied Geoscience, P.O. Box 6012, 2600 JA Delft, The
Netherlands
IGWMC Key: 4752/54 Model Name: AQ-AS/AQ-EF Released: 1989
Authors: Kovar, K., Leijnse, A.
AQ-AS is a computer program package for calculation of ground-water streamlines and isochrones due to
well pumpage and natural flow in homogeneous infinite multi-layered aquifer-aquitard systems. The program
is based on superposition of analytical solutions and includes both forward and backward particle tracking
using Runge-Kutta integration. The menu-driven interactive program computes and displays streamline
geometry, traveltimes, and isochrones. It includes help screens and error checking.
AQ-EF is a menu-driven, interactive computer program package for calculation of ground-water streamlines
and isochrones in multi-layered, anisotropic heterogeneous aquifer-aquitard systems with steady-state or
transient flow conditions. The program handles forward or backward particle tracking using the head
distribution values computed by the program AQ-FEM. The package includes a module for plotting of the
results.
Contact Address: K. Kovar, RIVM - Nat. Inst. of Public Health and Environm. Protection, P.O. Box 1,
3720 BA Bilthoven, The Netherlands
A.6-1-4
-------
Appendix A.6, part 1 (continued)
IGWMC Key: 4920 Model Name: FLOWPATH Released: 1992
Authors: Franz, T., Guiguer, N.
FLOWPATH is an easy-to-use program for the analysis of two-dimensional steady- state groundwater flow
problems. The program calculates hydraulic head distributions, groundwater velocities, pathlines, travel
times, capture zones, and wellhead protection areas in confined, leaky-confined or unconfined, anisotropic,
heterogeneous aquifers. Pathlines are computed with a particle tracking method. The finite difference
model can handle up to 10,000 nodes in an irregular grid, over 100 wells, and over 100 zones of different
aquifer properties. The program has extensive and sophisticated graphic pre- and post-processing
capabilities.
Contact Address: Waterloo Hydrogeologic Software, 113-106 Seagram Drive, Waterloo, Ontario,
Canada N2L 3B8
IGWMC Key: 4922 Model Name: FLONET Released: 1992
Authors: ~
FLONET is a two-dimensional cross-sectional steady-state ground water flow model. It computes potentials,
streamlines, and ground-water velocities in a vertical section through a confined or unconfined aquifer. The
model is based on the dual formulation of potentials and stream functions using a finite element method.
It can handle heterogeneous, anisotropic conditions. The principal direction of the hydraulic conductivity
tensor can vary in space. The model can account for spatially variable leakage characteristics of under- and
overlying aquitards. For unconfined aquifers, the model seeks the water-table iteratively. The model comes
with a user-friendly interface and extensive graphics (contours, velocity plots, streamlines and flow nets.
Contact Address: Waterloo Hydrogeologic Software, 113-106 Seagram Drive, Waterloo, Ontario,
Canada N2L 3B8
IGWMC Key: 5001 Model Name: FLOWNET Released: 1989
Authors: Van Elburg, H., Hemker, C.J., Engelen, G.B.
FLOWNET is used for interactive modeling of two-dimensional steady-state flow in an heterogeneous and
anisotropic cross-section of the saturated zone. It generates a flownet, composed of flow lines and
equipotential lines, obtained by a five-point finite difference approximation to calculate heads and linear
interpolation to determine equipotential lines. The matrix equation is solved using the conjugate gradient
method. The streamlines are determined from the flow function which in turn is determined using the adjoint
function of the potential function. The model handles hydraulic head boundary conditions variable along
the boundary- It has options for waterbalance calculations and HP-plotter output.
Contact Address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
IGWMC Key: 5004 Model Name: MFLOP (FLOw Pattern) Released: 1989
Authors: Hemker, C.J.
MFLOP is a simple microcomputer program for the immediate generation of streamlines of well fields with
superimposed uniform flow under confined conditions.
Contact Address: C.J. Hemker, Elandsgracht 83, 1016 TR Amsterdam, The Netherlands
A.6-1-5
-------
Appendix A.6, part 1 (continued)
IGWMC Key: 5200 Model Name: FLOWNS Released: 1989
Authors: Bramlett, W., Borden, B.C.
FLOWNS is a simple-to-use program for generating two dimensional flow nets for steady-state flow in any
saturated rectangular domain with any combination of constant head or constant flux (including zero flux)
boundary conditions. The domain might be either horizontally (areal) or vertically (cross-section) oriented.
The program approximates with discrete values the continuous distributions of potential and stream function
using finite difference approximations of the Laplace equation. The hydraulic conductivity distribution may
be anisotropic and/or heterogeneous. A contouring program is required to generate the final stream and
equipotential lines.
Contact Address: R.C. Borden, North Carolina St. Univ., Civil Eng. Dept, Rayleigh, NC 27695
IGWMC Key: 5300 Model Name: QUICKFLOW Released: 1991
Authors: --
QUICKFLOW is an interactive analytical model that simulates two-dimensional steady-state and transient
ground-water flow. The steady-state module simulates flow in a horizontal plane using analytical functions
developed by Strack (1989), including wells, uniform recharge, circular recharge/discharge areas, and line
sources or sinks in confined and unconfined aquifers. The model generates streamlines, particle traces and
head contours. The transient module calculates heads using equations developed by Theis (1935) and by
Hantush and Jacob (1955) for confined and leaky confined aquifers, respectively, and includes a particle
tracking option. Each module uses the principle of superposition to evaluate the effects of multiple wells
in a uniform regional flow field.
Contact Address: Geraghty & Miller, Inc., Modeling Group, 10700 Park Ridge Blvd., Suite 600, Reston,
VA 22091
IGWMC Key: 5340 Model Name: CTRAN/W (Contaminant Transport) Released: 1992
Authors: -
CTRAN/W is a finite element model for simulation of steady-state and transient movement of contaminants
through saturated/unsaturated soil. The model allows for advection, dispersion, adsorption and decay. It
handles transient concentration and mass-flux boundary conditions. The program runs under Microsoft
Windows 3.0. and uses a pull-down menu driven graphical interface with many graphical display and editing
functions. It is integrated with SEEP/W, a two-dimensional finite element flow simulator. CTRAN can model
contaminant movent by particle tracking from user-defined locations.
Contact Address: Geo-Slope International, #830, 633 - 6th Avenue S.W., Calgary, Alberta, Canada
T2P 2Y5
IGWMC Key: 5501 Model Name: GEOTRACK Released: 1991
Author: Srinivasan, P.
GEOTRACK is a graphics software program used to display pathlines generated by the USGS particle
tracking program , MODPATH, for ground-water flow simulations performed using the USGS
three-dimensional finite difference flow model MODFLOW or the three-dimensional finite difference flow and
transport model FTWORK. A simplified fence-diagram with hidden line removal can be constructed to be
displayed together with the calculated pathlines. The program allows for importing a surface feature map
showing buildings, trenches, roads, etc. The program allows the user to rotate the three-dimensional
diagram in real time.
continued
A.6-1-6
-------
Appendix A.6, part 1 (continued)
GEOTRACK -- continued
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza. Suite 100, Sterling, VA 22170
IGWMC Key: 5600 Model Name: STLINE Released: 1990
Authors: -
STLINE is a 3D particle tracking program using intercell flow rates computed by a finite difference model.
The specific discharge vectors are converted to average linear flow velocities. Particle movements within
the velocity field are computed by a linear interpolation scheme using a local coordinate system embedded
in the global coordinate system of the numerical model. Intracell-particle translations and traveltimes are
based on a linear variation in velocities in the cell. The trajectory of each particle is stored in memory as
a series of particle translations each with a specific and accumulated travel time within the global coordinate
system. Particle trajectories can be displayed in each of the three orthogonal planes of the Cartesian
coordinate system.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, Suite #100, Sterling, VA 22170
IGWMC Key: 5822 Model Name: SAFTAP Released: 1991
Authors: Huyakorn, P.S., Blandford, T.N.
SAFTAP (SAturated Flow and Transport And Particle tracking) simulates saturated groundwater flow and
solute transport in 3D. It is composed of two separate modules: the flow and transport module FTM, and
the particle tracking module PTM. FTM is a finite element code for multi-aquifer systems with a wide range
of aquifer conditions (e.g., confined, unconfined or partially confined with storage conversion). It analyses
3D unconfined flow using a saturated-pseudo unsaturated modeling approach, allowing the prediction of
the water table and flow rates without characterization of the unsaturated zone. Many types of steady-state
or time-dependent boundary conditions can be used. Transport mechanisms considered include advection,
dispersion, molecular diffusion, adsorption, and first-order degradation.
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 900. Herndon, VA 22070
IGWMC Key: 6590 Model Name: BEAVERSOFT Released: 1992
Authors: Bear, J., Verruijt, A.
BEAVERSOFT is a package of analytical and numerical solutions for groundwater flow and solute transport.
It includes programs for steady and non-steady state two-dimensional flow in heterogeneous aquifers, for
flow through dams, for transport of pollutants by advection and dispersion and for saltwater intrusion
problems.
Contact Address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6603 Model Name: ASM Released: 1991
Authors: Kinzelbach, W., Rausch, R.
ASM (Aquifer Simulation Model) is a menu-driven numerical model for steady-state or transient groundwater
flow and (uncoupled) solute transport. The two-dimensional block-centered finite difference equations for
(leaky-)confined or unconfined flow are solved using either the IADI or PCG method. Pathlines and
isochrones around pumping well are computed by point-tracking in the velocity filed using Euler integration.
continued
A.6-1-7
-------
Appendix A.6, part 1 (continued)
ASM - continued
Solute transport is simulated by the random walk method based on the Ito-Fokker-Planck theory. The model
can simulate variable well rates, constant flux and constant head boundaries, and constant or instantaneous
contaminant sources. It includes various graphic display option to view the simulation results.
Contact Address: W. Kinzelbach, Gesamthochschule Kassel- Universitat, FB 14, Moritzstr. 21, D-3500
Kassel, Germany; or Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401.
IGWMC Key: 6604 Model Name: PAT Released: 1990
Authors: Kinzelbach, W., Rausch, R.
PAT is an analytical model for the computation and graphical representation of pathlines and travel times
of groundwater in an infinite or semi-infinite, homogeneous and isotropic confined aquifer or in an infinite
strip of such an aquifer. The computed steady-state flow field might include arbitrary pumping or injection
wells superposed on a natural uniform regional flow. The model is screen-oriented and fully interactive.
Contact Address: W. Kinzelbach, Geasamthochschule Kassel - Universitat, Moritzstrasze 21, D-3500
Kassel, Germany; or Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401.
IGWMC Key: 6650 Model Name: GWPATH Released: 1990
Author: Shafer, J.M.
GWPATH is an interactive microcomputer-based software package for estimating horizontal or vertical fluid
pathlines and traveltimes in fully saturated ground-water flow domains. The model is applicable to
two-dimensional heterogeneous, anisotropic flow systems, and features forward and reverse pathline
tracking, time-related capture zone analysis, and multiple pathline capture detection mechanisms. It requires
as input a regular, cell-based distribution of observed or computed hydraulic heads.
Contact Address: J.M. Shafer, 1013 Devonshire Drive, Champaign, IL 61821
A.6-1-8
-------
Appendix A.6: Saturated Flow; Pathline Models, Part 2: Usability and Reliability
IGWMC
Key
741
1791
1820
1822
2072
2092
2120
2770
3940
3943
3982
3984
4591
4660
4752/54
4920
4922
5001
5004
5200
Model
USGS FRONT-
TRACKING
SLAEM/SLW/
SLWL/SYLENS
FLOP series
FRONT
FE3DGW
VTT
PATHS
CONFLOW
RESSQ
WHPA
PATH3D
MODPATH
MAGNUM-3D
FLOSA
AQ series
FLOWPATH
FLONET
FLOWNET
MFLOP
FLOWNS
Usability
Preprocessor
N
Y
Y
Y
N
N
U
U
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
U
U
Postprocessor
N
Y
Y
Y
N
N
U
U
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
U
U
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problem*
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
Y
Y
Y
N
N
U
U
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Y
U
Support
L
Y
Y
N
N
N
U
U
Y
Y
Y
Y
U
Y
Y
Y
Y
L
L
U
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
N
N
N
U
U
U
U
U
Y
U
U
U
U
U
U
U
U
U
U
U
Verified
L
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KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
A.6-2-1
-------
Appendix A.6, part 2 (continued)
IGWMC
Key
5300
5340
5501
5600
5822
6590
6603
6604
6650
Model
QUICKFLOW
CTRAN/W
GEOTRACK
STLINE
SAFTAP
BEAVERSOFT
ASM
PAT
GWPATH
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A.6-2-2
-------
Appendix B.1: Variably Saturated Flow; Numerical Models, Part 1: Model Description
IGWMC Key: 21 Model Name: UNSAT2 Released: 1979
Authors: Neuman, S.P., R. A. Feddes, and E. BresJer.
UNSAT2 is a two-dimensional finite element model for horizontal, vertical, or axisymmetric simulation of
transient flow in a variably saturated, nonuniform anisotropic porous medium. The governing equation is
the Richard's equation expressed in terms of pressure head. Boundary conditions included are Dirichlet and
Neumann, and seepage face. UNSAT2 is capable of simulating infiltration and evaporation as head-
dependent conditions, determined after the fluid pressure is calculated. Evapotranspiration is simulated
through user specified minimum allowed pressure head at the soil surface, maximum evaporation rate, and
soil surface geometric data. User supplied input for simulation of evapotranspiration includes root zone
geometric data, root effectiveness function, plant species wilting pressure, and maximum transpiration rate.
The code can use both quadrilateral and triangular elements. Unsaturated hydraulic properties must be
input in table form; internally, the code uses linear slopes between the data points for interpolation. UNSAT2
has a restart feature for simulating changing boundary conditions. The equation are solved with a band
solver; nonlinearities are handled by a Picard iteration scheme.
Contact Address: S.P. Neuman, Dept. of Hydrology and Water Resources, University of Arizona,
Tucson, AZ 85721
IGWMC Key: 120 Model Name: TRUST Released: 1984
Author: Narasimhan, T.N.
TRUST is an integrated finite difference simulator for computation of transient pressure head distributions
in multidimensional, heterogeneous, variably saturated, deformable porous media with complex geometry.
Deformation of the skeleton may be nonefastic. The polygon-based model considers pressure-dependent
density variations. The code calculates internally hydraulic conductivity and fluid mass capacity from
intrinsic permeability, fluid viscosity, fluid density, gravitational constants, void ratio, and compressibilities.
The model allows for hysteresis. The governing equations are solved by an mixed explicit-implicit scheme,
using a pointwise iterative solver. Optionally, a direct solver version is available form the author. This
scheme recognized that regions with small time constants might be weakly coupled, resulting in a highly
effective iterative solution algorithm. All boundaries of the flow domain are handled by a general head
boundary algorithm. Thus, any boundary condition is developed by manipulating a conductance term that
comprises the coefficient of the head differential between interior and exterior boundary node. In addition,
TRUST can handle seepage faces. The recent versions of TRUST allow both harmonic and geometric
means for the conductance term and includes an algorithm for automatically generating successive time step
durations.
Modifications were made to the code to simulate flow in fractured unsaturated porous media. These
modifications include additional characteristic curves and relative permeability curves, van Genuchten
formulae for matrix blocks, gamma distribution formulae for discrete fracture grid blocks, hyperbolic
characteristic curves of Pickens, and a new effective area factor. The new version of TRUST uses either the
existing efficient iterative solver or a new direct solution.
Contact Address: Narasimhan, T.N., Dept. of Materials Sc. and Mineral Eng., University of California,
Berkeley, CA 94720
B.1-1-1
-------
Appendix B.I, part 1 (continued)
IGWMC Key: 122 Model Name: FLUMP Released: 1981
Authors: Narasimhan, T.N., and S.P. Neuman
FLUMP is a finite element program for the computation of steady and nonsteady, two-dimensional areal or
cross-sectional pressure-head distribution in heterogeneous, anisotropic, variably saturated porous media
with complex geometry. FLUMP is especially suited for problems with moderate or high saturation. Some
stability problems may be encountered while applying code to desiccated soils.
Contact Address: Narasimhan, T.N., Dept. of Materials Sc. and Mineral Eng., University of California,
Berkeley, CA 94720
IGWMC Key: 1092 Model Name: FLO Released: 1985
Author: Vandenberg, A.
FLO simulates the elements of the hydrological cycle directly influenced by soil and surface drainage
improvements. Total discharge from a drained plot includes surface runoff, and drain discharge is estimated.
Detailed accounts of unsaturated flow is considered, including capillary forces and evapotranspiration.
Contact Address: Vandenberg, A., National Hydrology Research Institute, Inland Waters Directorate,
Ottawa, K1A OE7 Ontario, Canada
IGWMC Key: 1771 Model Name: MUST Released: -1985
Author: De Laat, P.J.M.
MUST (Model for Unsaturated flow above a Shallow water Table)is a finite difference model which simulates
one-dimensional vertical, unsaturated groundwater flow, evapotranspiration, plant uptake, and interception
of precipitation by plants.
Contact Address: De Laat, P.J.M, International Inst. for Hydraulic & Env. Eng., Oude Delft 95, Delft,
The Netherlands
IGWMC Key: 2071 Model Name: UNSAT1D Released: 1987
Authors: Gupta, S.K., C.S. Simmons, F.W. Bond, and C.R. Cole
UNSAT1D is a one-dimensional finite difference model for simulation of transient vertical unsaturated flow
in a wide variety of geologic environments and boundary conditions. The program simulates infiltration,
vertical seepage, and plant uptake by roots as function of the hydraulic properties of soil; soil layering; root
growth characteristics; evapotranspiration rates; and frequency, rate, and amount of precipitation and/or
irrigation.
Contact Address: Simmons, C.S., Battelle Pacific NW Laboratories, P.O. Box 999, Richiand, WA 99352
B.1-1-2
-------
Appendix B.1, part 1 (continued)
IGWMC Key: 2062 Model Name: SOILMOP Released: 1982
Authors: Ross, D.L, and H.J. Morel-Seytoux
SOILMOP is an analytical model to predict ponding time, infiltration rate and amount, and water content
profiles under variable rainfall conditions. The model solves a one-dimensional flow equation in a
homogeneous soil. Air phase is also included.
Contact Address: Morel-Seytoux, H.J., Colorado St. Univ.. Dept. of Civil Eng., Fort Collins, CO 80523
IGWMC Key: 2550 Model Name: SWACROP Released: 1983
Authors: Wesseling, J.G., P. Kabat, B.J. van den Broek, and R.A. Feddes
SWACROP (Soil WAter and CROP production model) is a transient one-dimensional finite difference model
for simulation of the unsaturated zone, which incorporates water uptake by roots. The soil profile is divided
into several layers (containing one or more compartments of variable thickness) having different physical
properties. The partial differential equation for flow in the unsaturated system is solved using a implicit finite
difference scheme. An explicit linearization of the hydraulic conductivity and soil water capacity is used.
Knowing the initial conditions (i.e. water content or pressure head distribution profile) and top and bottom
boundary conditions, the system of equations for all the compartments is solved for each (variable) timestep
by applying the so-called Thomas tri-diagonal algorithm. The iteration procedure within each timestep allows
calculation of all water balance terms for each time period selected.
For the top boundary condition data on rainfall, potential soil evaporation and potential transpiration are
required. When the soil system remains unsaturated, one of three bottom boundary conditions can be used:
pressure head, zero flux, or free drainage. When the lower part of the system remains saturated, one can
either give the ground-water level or the flux through the bottom of the system as input. In the latter case
the ground-water level is computed. The rate of vegetation growth, both potential and actual can be
simulated in the crop growth submodel linked to the main water model in a complex dynamic way.
However, both models can easily be run separately.
Contact Address: Winand Staring Centre, Dept. of Agrohydrology, Wageningen, The Netherlands
IGWMC Key: 2890 Model Name: SEEPV Released: 1980
Author: Davis, LA.
SEEPV is a transient finite difference model to simulate vertical seepage from a tailings impoundment in
variably saturated flow system; the program takes into consideration the interaction between an
impoundment liner and the underlying aquifer.
Contact Address: Water, Waste and Land. Inc., 1311 S. College Ave., Fort Collins, CO 80524
IGWMC Key: 2983 Model Name: SOMOF Released: 1982
Author: Wesseling, J.W.
SOMOF is a finite difference model for the simulation of transient unsaturated soil moisture flow in a vertical
profile. The model handles various processes, including infiltration from precipitation, capillary forces,
evapotranspiration, gravity drainage, ponding, and plant uptake.
Contact Address: Wesseling, J.W., Delft Hydraulics Laboratory, P.O. Box 152, 8300 AD Emmeloord,
The Netherlands
B.1-1-3
-------
Appendix B.I, part 1 (continued)
IGWMC Key: 3370 Model Name: FEMWATER/FECWATER Released: 1987
Authors: Yeh, G.T., and D.S. Ward
FEMWATER is a two-dimensional finite element model to simulate transient, cross-sectional flow in
saturated-unsaturated anisotropic, heterogeneous porous media. The model is designed to treat both point
sources/sinks and non-point sources/sinks, and to handle a wide variety of non-steady state boundary
conditions, including a moving water-table and seepage faces. It allows three alternative approximations for
the time derivative, has three options for estimating the non-linear matrix, and a direct and an iterative matrix
solution option. Furthermore, the program includes automatic time-step
adjustment and has an option to consider axisymmetric problems.
Contact Address: G.T. Yeh, Penn State University, Dept. of Civil Eng., 225 Sackett Bldg, University
Park. PA 16802
IGWMC Key: 3377 Model Name: 3DFEMWATER Released: 1987
Author: Yeh, G.T.
3DFEMWATER is a three-dimensional finite element model for simulation of water steady state and transient
flow through saturated-unsaturated media. The model is designed to handle anisotropic and heterogeneous
geologic media, time-varying distributed and point sources and sinks, a wide variety of boundary conditions,
including a moving water table and seepage faces. There are three options for estimating the nonlinear
matrix, two options for solving the linearized matrix equation, and it includes automatic time step adjustment.
Contact Address G.T. Yeh, Penn State University, Dept. of Civil Eng., 225 Sackett Bldg, University
Park, PA 16802
IGWMC Key: 3431 Model Name: UNSAT-1 Released: 1985
Author: Van Genuchten, M.Th.
UNSAT-1 is a Hermetian finite element solution to the Richards' equation for transient one-dimensional,
variably saturated flow in layered soils. The model can handle both abrupt layering and smoothly changing
profile properties.
Contact Address: Van Genuchten, M., USOA Salinity Laboratory, 4500 Glenwood Drive, Riverside, CA
92501, or Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden,
CO 80401.
IGWMC Key: 3570 Model Name: INFIL Released: 1987
Author: Vauclin, M.
INFIL is a finite difference model which solves for ponded infiltration into a deep homogeneous soil. The
model is based on the Philip series solution (1957) of a one-dimensional form of the Richards equation.
Output includes water content profile and amount and rate of infiltration at different simulation times. The
program, which requires the soil properties to be expressed in mathematical form, is designed to
accommodate three different sets of these functions. They include the four parameter function of Vauclin
(1979), the three parameter functions of Brutseart (1966 and 1967), and the two parameter function of
Brooks and Corey (1964). A modified version by A.I. El-Kadi also includes a van Genuchten function (1978).
Contact address: M. Vauclin, Institute de Mecanique de Grenoble, BP 68, 38402 St. Martin D'Heres
- Cedex France, or Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401.
B.1-1-4
-------
Appendix B.1, part 1 (continued)
IGWMC Key: 3660 Model Name: GRWATER Released: 1981
Authors: Kashkuli, H.A.
GRWATER is a finite difference model to predict the decline of ground water mounds developed under
recharge in an isotropic, heterogeneous water table aquifer. The model has two modules, one for transient
one-dimensional unsaturated flow above the water table which handles infiltration and evapotranspiration,
and one for transient two-dimensional horizontal saturated flow in the aquifer.
Contact Address: O.K. Sunada, Dept. of Civil Eng., Colorado State University. Fort Collins, CO 80523
IGWMC Key: 4340 Model Name: UNSAT-H Released: 1985
Authors: Payer, M.J., and G.W. Gee
UNSAT-H is a one-dimensional finite difference model for simulation of vertical unsaturated soil moisture
flow. It simulates infiltration, drainage, redistribution, surface evaporation and plant water uptake from soil.
The model's numerical technique is specially designed for arid zones characterized by very dry soils similar
to the Hanford site (Washington).
Contact Address: Payer, M.J., Battelle Pacific Northwest Lab., P.O. Box 999, Richland, WA 99352
IGWMC Key: 4380 Model Name: INFGR Released: 1985
Authors: Craig, P.M., and E.G. Davis
INFGR is one-dimensional model to estimate the infiltration rate using the Green and Ampt equation. The
compression method is used to estimate infiltration during low rainfall periods. The model works well for
determining infiltration but performs poorly in determining soil moisture content.
Contact Address: Davis, E.C., Oak Ridge National Lab., Environm. Sciences Div., Oak Ridge,
Tennessee 37830
IGWMC Key: 4390 Model Name: FLOWVEC Released: 1983
Authors: Li, R-M., K.G. Eggert, and K.Zachmann
FLOWVEC utilizes a vector processor for solving three-dimensional, variably saturated flow problems. The
model employs a finite difference technique in the formulation of the governing equations and a block
implicit scheme in the solution.
Contact Address: R.-M. Li, Simons, Li and Associates. Inc.. P.O. Box 1816, Fort Collins. CO 80522
IGWMC Key: 4400 Model Name: LANDFIL Released: 1984
Author: Korfiatis, G.P.
LANDFIL simulates the movement of moisture through the unsaturated zone using a finite difference solution
for the one-dimensional flow equation. Conditions simulated are pertinent to landfills. Precipitation,
evapotranspiration and redistribution are considered. Both lined and unlined landfills may be simulated.
Contact Address: G.P. Korfiatis, Stevens Inst. of Technology, Dept. of Civil Eng., Hoboken, NJ 07030
B.1-1-5
-------
Appendix B.1, part 1 (continued)
IGWMC Key: 4410 Model Name: HSSWDS Released: 1982
Authors: Perrier, E.R., and A.C. Gibson
HSSWDS is a one-dimensional, deterministic, water budget model to estimate the amount of moisture
percolation through different types of landfill. The model was adopted from CREAMS, the U.S. Department
of Agriculture hydrologic model. It includes recharge from precipitation including snowmelt, surface runoff
and evapotranspiration.
Contact Address: Water Resources Eng. Group, Env. Lab., U.S. Army Engineer Waterways
Experiment Station, Vicksburg, Mississippi 39185, or Municipal Env. Res. Lab.,
Solid and Hazardous Waste Res. Div., U.S. Env. Prot. Ag., Cincinnati, OH 45268
IGWMC Key: 4980 Model Name: PC-SEEP Released: 1992
Authors: Krahn, J., D.G. Fredlund, L Lam, and S.L Barbour
PC-SEEP is an interactive finite element program for simulating steady-state and transient groundwater flow
in both the saturated and unsaturated zones. It can simulate surface infiltration and evapotranspiration and
handle internal drains. PC-SEEP is designed to analyze seepage through earth dams, watertable location
and fluctuations, and mounding of the watertable underneath a leaking waste pond. The model computes
nodal pore-water pressures, hydraulic heads, velocities, flow directions and flow gradients. It includes
postprocessors for finite element mesh plots, head contours and velocity vector plots. PC-SEEP provides
options to use either an in-core or an out-of-core iterative solver for the nonlinear flow equations.
Contact Address: J. Krahn, Geo-Slope Programming Ltd., 7927 Silver Springs Road NW, Calgary,
Alberta, Canada T3B 4K4
IGWMC Key: 5010 Model Name: SIMGRO Released: 1987
Author: Querner, E.P.
SIMGRO (SIMulation of GROundwater flow and surface water levels) simulates flow in the saturated zone,
the unsaturated zone, and a surface water system. The saturated zone model consists of a
quasi-threedimensional finite element model with an implicit calculation scheme. The unsaturated zone is
modeled by means of two reservoirs, one for the root zone and one for the subsoil. The root zone is treated
using a water balance model and includes storage and resulting change in phreatic level, capillary rise,
percolation and evapotranspiration. The surface water system, representing a network of small channels,
is considered as a single reservoir with criteria for water supply, discharge, water level control, and
extraction for sprinkling.
Contact Address: E.P. Querner, Inst. for Land and Water Management Research (ICW), P.O. Box 35,
6700 AA Wageningen, The Netherlands
B.1-1-6
-------
Appendix B.1, part 1 (continued)
IGWMC Key: 5057 Model Name: VADOSE Released: -
Authors: -
VADOSE is a 3-dimensional analytical model for flow into an unsaturated anisotropic or isotropic porous
medium. It can predict the spread of a toxic solution seeping into the ground, or a lixiviant flowing in a heap
leach. The saturation and/or the flow velocity can be calculated as a function of space and time for the leak
configuration specified by the user. The leak configuration handled by the model can be a combination of
point sources or rectangular sites (ponds, land treatment sites, sewage lagoons, or similar sites). The effect
of each leak/flow is calculated and the final solution is obtained by superposition. Impermeable boundaries,
vertical or horizontal, can be included. The model computes saturation, suction tension (capillary pressure),
and velocities.
Contact Address: In Situ, Inc., P.O. Box 1, Laramie, WY 82070
IGWMC Key: 6400 Model Name: UNSAT Released: 1985
Authors: Khaleel, R., and T-C.J. Yeh
UNSAT is a Galerkin finite element model for solving the one-dimensional, transient flow equation in
unsaturated porous media. It estimates the rate of infiltration into soil as well as the moisture distribution
following infiltration. Both differential and cumulative mass balance errors are given to illustrate accuracy
of the numerical scheme.
Contact Address: Khaleel, R., New Mexico Inst. of Mining and Technology, Dept. of Geoscience,
Socorro, NM 87901
IGWMC Key: 6630 Model Name: WATERFLO Released: 1985
Author: Nofziger, D.L
The WATERFLO model is based on a finite difference solution of the one-dimensional nonlinear Richards
equation for simulation of water movement through homogeneous soils. The interactive microcomputer
program can accommodate finite and semi-finite soil systems. It provides for the following boundary
conditions at the soil surface: constant potential, constant flux density, rainfall or sprinkler infiltration rate,
and mixed type (flux and potential boundary condition).
Contact Address: IFAS - Software Support, Univ. of Florida, Building 664, Room 203, Gainesville, FL
32611
Note: See also Appendix C.3; most solute transport models include a flow simulation module.
B.1-1-7
-------
Appendix B.1: Variably Saturated Flow; Numerical Models, Part 2: Usability and Reliability
IGWMC
Key
21
120
122
1092
1771
2071
2062
2550
2890
2983
3370
3377
3431
3570
3660
4340
4380
4390
4400
4410
4980
Model
UNSAT2
TRUST
FLUMP
FLO
MUST
UNSAT1D
SOILMOP
SWACROP
SEEPV
SOMOF
FEMWATER/
FECWATER
3DFEMWATER
UNSAT-1
INFIL
GRWATER
UNSAT-H
INFGR
FLOWVEC
LANDFIL
HSSWDS
PC-SEEP
Usability
Preprocessor
N
Y
N
N
U
Y
N
Y
U
U
N
N
N
Y
N
U
U
U
U
U
Y
Postprocessor
N
Y
N
N
U
Y
N
Y
U
U
N
N
N
Y
N
U
U
U
U
U
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
N
N
Y
N
Y
U
U
N
N
N
Y
U
U
U
U
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N
Y
Support
L
L
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L
Y
N
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L
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Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
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Y
Y
Y
Y
Y
Y
Y
Y
U
U
Y
Y
Y
Y
Y
Y
Y
Y
U
U
U
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Y
Y
U
U
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U
N
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KEY: Y = YES N = NO L = LIMITED M = MANY F = FEW U = UNKNOWN
B.1-2-1
-------
Appendix B.1, part 2 (continued)
IGWMC
Key
5010
5057
6400
6630
Model
SIMGRO
VADOSE
UNSAT
WATERFLO
Usability
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B.I-2-2
-------
Appendix B.2: Variably Saturated Flow; Parameter Estimation Models, Part 1: Model
Description
IGWMC Key: 3433 Model Name: ONESTEP Released: 1985
Authors: Kool, J.B., J.C. Parker, and M.Th. Van Genuchten.
ONESTEP is a nonlinear parameter estimation model for evaluating soil hydraulic properties from one-step
outflow experiments in the one-dimensional flow. The program estimates parameters in the van Genuchten
soil hydraulic property model from measurements of cumulative outflow with time during one-step
experiments. The program combines non-linear optimization with a Galerkin finite element model.
Contact Address: J.C. Parker, Virginia Polytechnical Inst., Dept. Soil & Environmental Science,
Blacksburg, VA 24061, or Internal. Ground Water Modeling Ctr, Colorado Sch. of
Mines, Golden, CO 80401.
IGWMC Key: 5183 Model Name: SOILPROP Released: 1988
Authors: Mishra, S., J.C. Parker, and N. Singhal
SOILPROP is an interactive program to estimate soil hydraulic properties and their uncertainty from particle
size distribution data. Properties estimated by the program are the saturated hydraulic conductivity and
parameters in the van Genuchten and Brooks-Corey models which describe the relationship between soil
water content, capillary pressure and relative permeability. SOILPROP is based on the premise that the
soil-water retention function reflects a pore size distribution which in turn can be inferred from the grain size
distribution. The Arya-Paris procedure is used to compute theoretical water content versus capillary
pressure curve, which is then fitted to the two models. Covariances are estimated using a first-order error
analysis procedure. The saturated hydraulic conductivity in SOILPROP is estimated from the user-specified
porosity and grain-size distribution data using a Kozeny-Carmen type equation.
Contact Address: Environm. Systems & Technol., Inc., P.O. Box 10547, Blacksburg, VA 24062-0457
IGWMC Key: 5187 Model Name: FLOFIT Released: 1988
Authors: Kool, J.B., S. Mishra, and J.C. Parker
FLOFIT is a program to estimate unsaturated soil hydraulic properties and/or transport parameters from
1 -dimensional vertical flow/transport experiments. Three modes of operation are possible: 1) flow properties
may be estimated from transient flow data; 2) solute dispersion and linear adsorption parameters may be
estimated from steady flow transport data; or 3) flow and transport parameters may be estimated
simultaneously from transient unsaturated flow and tracer experiments. Hydraulic properties are described
by a hysteric van Genuchten model and dispersion by a scale-dependent function. Hydraulic and/or
transport parameters may differ between layers. Numerical inversion of governing equations is performed
using an efficient Levensberg-Marquardt algorithm.
Contact Address: Environm. Systems & Technol., Inc., P.O. Box 10457, Blacksburg, VA 24062-0457
B.2-1-1
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Appendix B.2, part 1 (continued)
IGWMCKey:6170 Model Name: FP Released: 1985
Authors: Su, C., and R.H. Brooks
FP is a program to determine the parameters of the retention function (the soil-water characteristic function)
from experimental data. Based upon the Pearson Type VIII distribution function, a general retention function
which relates the saturation to the capillary pressure in distributed soils has been formulated. This simple,
yet complete function has been shown to describe the imbibition as well as the drainage branch of the
retention curve. It is defined by four readily assessed parameters that either have physical significance
themselves or may be used to determine some hydraulic properties of the soil. Please see "Remarks" for
more information.
With the assumption that the Burdine integrals are adequate, a relative permeability function has been
derived through the substitution of the retention function for the integrands in the Burdine Integrals. The
permeability function is expressed in terms of the incomplete Beta function ration whose value may be
conveniently found in some mathematical tables.
A general pore-sized distribution function of soils has been obtained from the retention function. The
derivation of the pore-size distribution function enables more rigorous examination and further exploration
of the theories concerning water movement in partially saturated soils. In this respect, an explanation of the
phenomenon of air entrapment during imbibition has been offered through an energy concept based upon
the pore-size distribution function along with the retention function. Two criteria of affinity have been
established for porous media. Media are said to be affine if their corresponding pore-size distribution
parameters are identical. The scaling factor for the external dimension of the model has been chosen to
be the capillary pressure head at the inflection point of the retention curve, whose value is always finite. The
analysis of the effect of the pore-size distribution parameters upon the retention, permeability, and diffusivity
curves shows that the parameter governing the downward concavity of the retention curve is as important
as that governing the upward concavity when it comes to computing the permeability values from the
retention data.
Contact Address: Dept. of Agricultural Eng., Oregon State University, Corvallis, OR 97331, or Internal.
Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 6226 Model Name: SOHYP Released: 1986
Author: Van Genuchten, M. Th.
SOHYP is an analytical model for calculation of the unsaturated hydraulic conductivity function using soil
moisture retention data. The basis of SOHYP is a relatively simple equation for soil moisture
content-pressure head curve. The particular form of the equation enables one to derive closed-form
analytical expressions for the relative hydraulic conductivity, when substituted in the predictive conductivity
models of Burdine or Mualem. The resulting expressions for the hydraulic conductivity as function of the
pressure head contain three independent parameters which may be obtained by fitting the described soil
moisture retention model to experimental soil moisture retention data. The solution is based on automatic
curve-fitting using a nonlinear least squares method.
Contact Address: USOA Salinity Laboratory, 4500 Glenwood Drive, Riverside, CA 92501, or Internal.
Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
B.2-1-2
-------
Appendix B.2, part 1 (continued)
IGWMC Key: 6228 Model Name: RETC Released: 1991
Authors: Van Genuchten, M.Th., F.J. Leij, and S.R. Yates
RETC (Retention Curve Computer Code) uses theoretical methods to predict the soil water retention curve
and the hydraulic conductivity curve from measured soil water retention data. It uses several analytical
models to estimate water retention, unsaturated hydraulic conductivity or soil water diffusivity for a given soil.
It includes the parametric equations of Brooks-Corey and van Genuchten, which are used in conjunction
with the theoretical pore-size distribution models of Mualem and Burdine to predict unsaturated hydraulic
conductivity from observed soil water retention data. RTC can be used in a forward mode and in a
parameter fitting mode. In the forward mode it estimates the soil-water retention curve and hydraulic
conductivity; in the parameter fitting mode it determines the analytical model parameters.
Contact Address: U.S. Dept. of Agriculture, U.S. Salinity Lab., Agric. Res. Service, 4500 Glenwood
Drive, Riverside, Calif. 92501; Center for Subsurface Modeling Support (CSMOS),
R.S. Kerr Environmental Research Laboratory, U.S. Environmental Protection
Agency, P.O. Box 1198, Ada, OK 74820; or Internal. Ground Water Modeling Ctr,
Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 6330 Model Name: SOIL Released: 1987
Author: El-Kadi, A.I.
Using non-linear least-squares analysis, SOIL estimates soil-hydraulic properties. The code requires as input
pairs of measured water content and suction. The model includes the methods of Brooks and Corey (1964)
and Vauclin (1979) to estimate soil water characteristic function and the unsaturated hydraulic conductivity.
Contact Address: Internal. Ground Water Modeling Clr., Colorado Sch. of Mines, Golden, CO 80401
B.2-1-3
-------
Appendix B.2: Variably Saturated Flow; Parameter Estimation Models, Part 2: Usability and Reliability
IGWMC
Key
3433
5183
5187
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B.2-2-1
-------
Appendix C.1: Solute Transport; Analytical Models For Saturated Zone, Part 1: Model Description
IGWMC Key: 2037 Model Name: FRACSOL Released: 1981
Authors: G.E. Grisak and J.F. Pickens
FRACSOL is an analytical model for simulation of non-reactive advective-dispersive solute transport in planar
fractures with diffusion into adjacent matrix blocks. The solution solves for the transient concentration
distribution along the fracture as well as into the matrix.
Contact address: J.F. Pickens, Intera Technologies, Inc., 6850 Austin Center Blvd., #300, Austin, TX
78731
IGWMC Key: 2080 Model Name: GETOUT Released: 1983
Authors: H.C. Burkholder, M.O. Cloninger, W.V. Dernier, G. Jansen
GETOUT is a one-dimensional analytical model of advective-dispersive radionuclide transport in ground-
water subject to linear equilibrium sorption. The model handles radioactive decay for straight chains with
a maximum of three nuclides in one chain.
Contact address: National Energy Software Center (NESC), Argonne National Laboratory, 9700 South
Cass Avenue, Argonne, IL 60439
IGWMC Key: 2810 Model Name: WASTE Released: 1981
Authors: B. Ross and C.M. Koplik
WASTE is an analytical solution to compute one- or two-dimensional horizontal, or one-dimensional vertical,
steady or unsteady transport of radionuclides in confined or semi-confined, anisotropic, heterogeneous,
multi-aquifer systems. The model includes advection, dispersion, diffusion, linear adsorption, equilibrium ion
exchange and first-order radioactive decay. It is part of the NUTRAN package for calculation of doses to
humans from radionuclides carried out of deep geologic waste repositories by ground-water.
Contact address: Analytic Sciences Corporation, Energy & Environment Division, One Jacob Way,
Reading, MA 01867
IGWMC Key: 3380 Model Name: GRDFLX Released: 1982
Authors: R.B. Codell, K.T. Key, and G. Whelan
The program GRDFLX consists of two analytical models: (1) GRND calculates the vertically averaged
concentration at points in a uniform aquifer of finite thickness with constant physical transport properties;
and (2) FLUX calculates the flux of radioactive liquid effluent passing a plane perpendicular to the ground-
water flow direction. Both models assume a horizontal, limited area source. Radioactive decay is treated
separately from the transport computations to facilitate analysis of releases of long decay chains. The
models are based on Simpson's rule of integration. They include linear equilibrium adsorption (retardation)
and three-dimensional dispersion.
Contact address: R.B. Codell, U.S. Nuclear Regulatory Commission, Div. of Eng., Off. of Nuclear
Reactor Regulation, Washington, DC 20555.
C.1.-1-1
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 3432 Model Name: CXTFIT Released: 1984
Authors: J.C. Parker and M.Th. van Genuchten
The purpose of CXTFIT is to determine values for one-dimensional analytical solute transport parameters
using a nonlinear least-squares inversion method. The analytical model includes advection, dispersion,
diffusion, linear equilibrium sorption, first-order decay and zero-order production.
Contact address: J.C. Parker, Virginia Polytechn. Inst., Soil & Env. Sc. Dept., Blacksburg, VA 24061,
or International Ground Water Modeling Center, Colorado School of Mines, Golden,
CO 80401.
IGWMC Key: 4082 Model Name: LAYFLO Released: 1983
Authors: A.B. Gureghian and G. Jansen
LAYFLO is a one-dimensional, semi-analytical model for simulation of the migration of a three-member
radionuclide decay chain in a multi-layered geologic porous medium. The advective-dispersive transport
equation is solved using Laplace transformation. The model allows for two types of boundary conditions,
i.e. a continuous source as well as a band release mode, respectively. The solution of the non-dispersive
form of the mass transport equation can handle any number of layers, whereas for the general case the
number of layers is restricted to six. A graphics program using the DISPLA package is provided with
LAYFLO.
Contact address: Performance Assessment Dept., Off. of Nuclear Waste Isolation, Battelle Project
Management Division, 505 King Avenue, Columbus, OH 43201
IGWMC Key: 4620 Model Name: MASCOT Released: 1986
Author: A.B. Gureghian
MASCOT is a program providing analytical solutions for multi-dimensional transport of a four-member
radionuclide decay chain in an isotropic, homogeneous, confined ground-water system and includes linear
equilibrium sorption. It computes the two- and three-dimensional space-time dependent
convective-dispersive transport assuming steady-state, uniform ground-water flow. The model can handle
a single or multiple finite line source or a Gaussian distributed source in the 2D case, and a single or
multiple patch source or bivariate-normal distributed source in the 3D case.
Contact address: Battelle/OWTD, 7000 South Adams Str, Willowbrook, IL 60521
IGWMC Key: 4740 Model Name: SURMF Released: 1985
Authors: P.L Chambre, T.H. Pigford, W.W-L Lee, J. Ahn, et al.
SURMF is a series of analytical solutions for the dissolution and hydrogeologic near-field transport of
radionuclides from geologic repositories of nuclear waste. The models calculate the total surface mass flux
using the mass transfer theory from chemical engineering. The package includes models for advective-
(continued )
C.1.-1-2
-------
Appendix C.I, part 1 (continued)
SURMF - continued
dispersive radionuclide transport from various geometric waste forms through a backfill; transport through
a backfill using a non-linear sorption isotherm; transport through a backfill, where the solubility, diffusMty
and retardation coefficients are temperature dependent; a coupled near-field, far-field analysis where
dissolution rates and migration are temperature dependent; 3D transport from a point source; and a general
solution for the transport of radioactive chains.
Contact address: T.H. Pigford, Dept. of Nuclear Eng., Univ. of Calif., Berkeley, CA 94720
IGWMC Key: 4911 Model Name: OASIS Released: 1989
Authors: C.J. Newell, J.F. Haasbeek, LP. Hopkins, S.E. Alder-Schaller, et al.
OASIS is a graphical decision support system for ground-water contamination modeling developed for the
Macintosh II or SE personal computer using HyperCard software. OASIS is a collection of computer tools
including extensive computerized documentation, two chemical databases, a hydrogeologic database
derived from a survey of 400 sites across the US and DRASTIC aquifer vulnerability index system, a
numerical 2-dimensional solute transport and biodegradation model --BIOPLUMEII--, and an analytical solute
transport model --ODAST. It includes extensive graphical pre- and postprocessing for BIOPLUMEII. OASIS
provides graphical and analytical support to decision makers and technical support personnel.
Contact address: P.B. Bedient, Rice Univ., Dept. of Env. Sc. and Eng., Houston, TX 77251
IGWMC Key: 5024 Model Name: PATHRAE Released: 1986
Authors: R.A. Fjeld, A.W. Elzerman, T.J. Overcamp, N. Giannopoulos et al.
PATHRAE is a computer code for assessing human health risk associated with low level radioactive waste
disposal at municipal dumps and sanitary landfills. The code contains algorithms for analyzing ten different
pathways including the subsurface transport of contaminants to a stream and migration to a well. The risk
assessment procedure consists of: (1) specification of the source term, (2) analysis of environmental
transport, and (3) estimation of the risk of health effects. Contaminant transport in the unsaturated zone is
approximated by assuming plug flow resulting in a retarded contaminant entry in the saturated zone.
Transport in the saturated zone is modeled as an analytical solution to the advective-dispersive transport
equation including radioactive decay.
Contact address: R.Fjeld, Dept. of Env. Syst. Eng., Clemson Univ., Clemson, SC 29634-0919
IGWMC Key: 5055 Model Name: PLUME Released: -
Authors: -
PLUME is a two-dimensional analytical contaminant transport model. The dispersion of a contaminant in an
aquifer is calculated as a function of time, distance, and direction of the contaminant source. Plumes from
up to 50 rectangular sources can be modeled. Three types of contaminant sources can be considered: (1)
an instantaneous source, (2) a source with a constant rate of contamination, and (3) a source with an
exponentially declining rate of contamination. The concentration profile is given at a line of interest or at a
fixed point as a function of time. The model includes the effects of regional ground-water flow, dispersion,
linear adsorption, and radioactive decay, and conversion by first-order rate law. The output includes site
layout and concentration contours.
Contact address: In Situ Inc., P.O. Box 1, Laramie, WY 82070
C.1.-1-3
-------
Appendix C.1, part 1 (continued)
IGWMC Key. 5174 Model Name: FRACQUAL Released: -
Authors: -
FRACQUAL is a program that simulates the movement of a solute through a planar fracture in a fractured
rock aquifer, including molecular diffusion into the non-fractured rock. In the program, the effects of
advection, adsorption, decay, and diffusion into the rock matrix are simulated. The program uses the
analytical equation of Tang, Frind, and Sudicky. Time-varying sources of contamination may be simulated
using superposition.
Contact address: Koch and Assoc., 2921 Greenway Dr., Ellicot City, MD 21043
IGWMC Key: 5175 Model Name: POLLUT Released: -
Authors: -
POLLUT is an analytical model for two-dimensional simulation of a contaminant plume using the Wilson and
Miller equation of 1978. The program computes the concentration at any point in space due to the
continuous release of a solute at a point in an aquifer. The program includes the effects of advection (one
dimension), dispersion (two dimensions), decay and linear adsorption. Up to 100 different continuous
sources may be simulated using superposition for time-varying sources.
Contact address: Koch and Assoc., 2921 Greenway Dr., Ellicot City, MD 21043
IGWMC Key: 5210 Model Name: PULSE Released: -
Author: LS. Slotta
PULSE is a one-dimensional analytical model for solute transport in confined or unconfined aquifers,
calculating concentration distribution in space and time. It simulates the fate of a contaminant initially present
as a distributed rectangular pulse. The model assumes no contaminant sources or sinks present.
Longitudinal dispersion, adsorption and first-order loss (decay) is included. The model presents tabular
output of contaminant concentration values at various distances from origin of pulse and for various times.
Contact address: Slotta Engineering Assoc., Inc., P.O. Box 1376, Corvallis, OR 97339
IGWMC Key: 5211 Model Name: CXPMPM Released:-
Author: LS. Slotta
CXPMPM is an analytical model for simulation of solute transport in confined or unconfined homogeneous,
isotropic aquifers. It calculates concentration distributions in space and time due to one-dimensional
advection, longitudinal dispersion, linear adsorption, and first-order loss (decay) for up to 250 area!
contaminant sources. The inlet boundary is a time-dependent concentration flux (constant, exponentially
decreasing, skewed or bell shaped distributions). The model provides tabular and graphical output of results.
Contact address: Slotta Engineering Assoc., Inc., P.O. Box 1376, Corvallis, OR 97339
C.1.-1-4
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 5212 Model Name: TDPLUME/TWODPLME Released: -
Author: LS. Slotta
TDPLUME/TWODPLME are two-dimensional analytical solute transport models for confined or unconfined
aquifers, the contaminant being convected and dispersing in X (flow direction) and Y (orthogonal to the flow
direction in a horizontal plane) directions. Two scenarios can be considered: initial distribution of
contaminant as a number of up to 250 rectangles with specified concentration, or a number of constantly
emitting chemical sources (line sources: TDPLUME, or large rectangular sources: TWODPLME). The models
are based on one-dimensional stationary ground-water flow, and include lateral and transverse dispersion,
linear adsorption, and first-order loss (decay). Calculation of concentration distribution in time and space.
Contact address: Slotta Engineering Assoc., Inc., P.O. Box 1376, Corvallis, OR 97339
IGWMC Key: 5242 Model Name: BLOB3D Released: -
Authors: -
BLOB3D is an analytical model simulating 3-dimensional transient solute transport from a parallelepiped
source in a finite thickness medium. It assumes known constant, uniform ground-water velocity field. It
computes the concentration of the solute at any point in time and for any distance from the source. It can
handle source or solute decay and solute retardation.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5243 Model Name: CRAFLUSH Released: -
Authors: -
CRAFLUSH is an analytical model for simulating 2-dimensional, transient solute transport in a series of
parallel fractures. It can handle longitudinal dispersion and diffusion of solute into the rock matrix. It
computes concentration of the solute at any time and distance from source.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5245 Model Name: HPATCH3D Released: ~
Authors: -
HPATCH3D is an analytical model for 3-dimensional, transient advective-dispersive solute transport from a
horizontal patch source which can be located at any depth in an aquifer with finite thickness. The model
assumes constant, uniform ground-water velocities. It computes the concentration of the solute at any time
and distance from the source and handles both source and solute decay and solute retardation.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
C.1.-1-5
-------
Appendix C.I, part 1 (continued)
IGWMC Key: 5246 Model Name: LJNE2D Released: -
Authors: -
LJNE2D is an analytical model for simulating 2-dimensional, transient advective-dispersive solute transport
with a vertical line source at x=0 in a finite thickness aquifer. The model assumes constant, uniform ground-
water velocities. It computes the concentration of a solute at any time and distance from the source. It can
handle both source and solute decay and solute retardation.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada, N2L 3G1
IGWMC Key: 5247 Model Name: PATCH3D Released: --
Authors: -
PATCH30 is an analytical model for 3-dimensional, transient advective-dispersive solute transport from a
vertical patch source at x=0 in a finite thickness aquifer. The model assumes constant, uniform ground-
water velocities. It computes the concentration of the solute at any time and distance from the source. It
can handle both source or solute decay and solute retardation.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5248 Model Name: SUPER1D Released: -
Authors: -
SUPER1D is an analytical model for simulating one-dimensional, transient advective-dispersive solute
transport based on the Ogata-Banks solution with superposition. It computes the concentration and flux
of a solute at any time and distance from the source. The source strength may vary with time. The model
can handle solute retardation.
Contact address: R.G. McLaren, Waterloo Centre for Groundwater Res., Univ. of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5310 Model Name: PRZMAL Released: -
Authors: J. Wagner and C. Ruiz-Calzada
PRZMAL is an aquifer linkage model for US EPA's Pesticide Root Zone Model (PRZM). It connects PRZM
with the analytical three-dimensional advective-dispersive transport model PLUME 3D developed at
Oklahoma State University. This linkage allows the user to predict non-conservative contaminant movement
from the point of application, in a continuous manner, into and within the aquifer.
Contact address: J. Wagner, Oklahoma State Univ., School of Chem. Eng., Stillwater, OK 74074
C.1.-1-6
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 6011 Model Name: RWH Released: 1992
Author: P.K.M. van der Heijde
RWH simulates solute transport in homogeneous isotropic, confined aquifers. It accounts for regional
groundwater flow and the superposed effects of production and injection wells. The effects of wells is based
on the Theis equation. The transport equation is solved via the particle-in-a-cell technique for convection
and the random walk technique for dispersion. Options for retardation and first-order decay are included.
The program utilizes screen graphics as the primary output device. It can be used for both educational
purposes and initial definition of more complex problems.
Contact address: Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6020 Model Name: PLUME Released: 1991
Author: P.K.M. van der Heijde
PLUME is an analytical model to calculate two-dimensional vertically averaged or three-dimensional
concentration distribution in a homogeneous aquifer with a continuous solute injection in a one-dimensional
regional flow field. It includes the simulation of dispersion, retardation, and radioactive decay. The source
is either a line source at a specified depth in the three-dimensional version or a vertically averaged area
source of specified width in the two-dimensional version. The source strength may vary in time. The
program uses Simpson's rule of integration and includes a subroutine to calculate concentration values on
a user-defined grid base.
Contact address: Internet. Ground Water Modeling Ctr.. Colorado Sch. of Mines. Golden. CO 80401
IGWMC Key: 6024 Model Name: PLUME2D Released: 1986
Author: P.K.M. van der Heijde
PLUME2D provides an analytical solution to calculate concentration distribution in a homogeneous, nonleaky
confined aquifer with uniform regional flow. The model uses the well-function for convection and dispersion
of a solute in a system with continuous injecting, fully penetrating wells. The program based on the
corrected Wilson and Miller solution (1978), has an option for retardation and first-order decay.
Contact address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden. CO 80401
IGWMC Key: 6100 Model Name: GROUND Released: 1982
Authors: R.B. Codell, K.T. Key and G. Whelan
GROUND is an analytical model for calculation of the flux into a river and the concentration at points
downgradient of a source with a single radioactive contaminant released from a vertical plane. The model
is developed for the limiting case of unidirectional advective transport with three-dimensional dispersion in
an isotropic aquifer. Furthermore, the model includes first-order decay and linear equilibrium adsorption as
represented by the retardation coefficient. The point concentration model uses Simpson's rule quadrature
of an arbitrary pulse release into a confined aquifer.
Contact address: R.B. Codell, U.S. Nuclear Regulatory Commission, Div. of Eng., Off. of Nuclear
Reactor Regulation, Washington, DC 20555.
C.1.-1-7
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 6120 Model Name: AT123D Released: 1987
Author: G.T. Yeh
AT123D is a generalized analytical transient, one- two-, and/or three-dimensional computer code developed
for estimating the transport of chemicals in a homogeneous aquifer system with uniform flow. The model
handles various source configurations and release characteristics. The transport mechanisms include
advection, hydrodynamic dispersion, linear adsorption, first-order decay/degeneration, and chemical losses
to the atmosphere.
Contact address: G.T. Yeh, Dept. Civil Eng., Penn. State Univ., University Park, PA 16802, or Internal.
Ground Water Modeling Center, Colorado School of Mines, Golden, CO 80401.
IGWMC Key: 6220 Model Name: ONE-D Released: 1982
Authors: M.Th. van Genuchten and W.J. Alves
ONE-D is a package of five analytical solutions to the one-dimensional convective-dispersive solute transport
equation with linear equilibrium adsorption, zero-order production, and first-order decay in a semi-infinite
homogeneous aquifer with a uniform flow field. The five solutions are based on different governing
equations and boundary conditions.
Contact address: M.Th. van Genuchten, U.S. Salinity Lab., U.S. Dept. of Agriculture, 4500 Glenwood
Drive, Riverside, CA 92501, or International Ground Water Modeling Center,
Colorado School of Mines, Golden, CO 80401.
IGWMC Key: 6227 Model Name: CFITIM Released: 1981
Author: M.Th. van Genuchten
CFITIM is a program for the estimation of the parameters for one-dimensional non-equilibrium
convective-dispersive solute transport in saturated porous media from miscible displacement experiments
using least squares analysis.
Contact address: M.Th. van Genuchten, U.S. Salinity Lab., U.S. Dept. of Agriculture, 4500 Glenwood
Drive, Riverside, CA 92501, or International Ground Water Modeling Center,
Colorado School of Mines, Golden, CO 80401.
IGWMC Key: 6250 Model Name: WELL Released: 1982
Author: LW. Gelhar
WELL is a program to determine the tracer concentration evolving in a pumping-recharge well system when
an instantaneous pulse of conservative tracer is introduced in the recharge well. The program is based on
the numerical approximation of a closed-form solution of the governing convective-dispersive equation for
transport in a homogeneous aquifer.
Contact address: LW. Gelhar, Dept. of Civil Eng., Mass. Inst. of Techn., Cambridge, MA 012139, or
Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
C.1.-1-8
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 6310 Model Name: LTIRD Released: 1985
Authors: I. Javandel, C. Doughty and C.F. Tsang
LTIRD simulates advective-dispersive transport in a radial flow field, calculating the dimensionless
concentration of a particular solute, injected into an aquifer, as a function of dimensionless time for different
values of dimensionless radius. It assumes a fully penetrating injection well with constant injection rate and
concentration at source, a homogeneous and isotropic aquifer of uniform thickness, and zero background
concentration. The evaluation of the analytical solution is based on numerical inversion of the Laplace
transform.
Contact address: I. Javandel, Lawrence Berkeley Lab., Earth Sc. Div., Berkeley, CA 94720, or Internal.
Ground Water Modeling Center, Colorado School of Mines, Golden, CO 80401.
IGWMC Key: 6311 Model Name: TDAST Released: 1985
Authors: I. Javandel, C. Doughty and C.F. Tsang.
TDAST evaluates an analytical solution to the two-dimensional convective-dispersive solute transport
equation. The model includes decay (both at the source and in the aquifer), and linear equilibrium
adsorption. It calculates C/CO at any point downstream from a finite strip source (orthogonal to direction
of flow) at any specified time. It assumes a homogeneous, isotropic aquifer of uniform thickness, a uniform
flow field, and zero background concentration.
Contact address: I. Javandel, Lawrence Berkeley Lab., Earth Sc. Div., Univ. of Calif., Berkeley, CA
94720, or International Ground Water Modeling Center, Colorado School of Mines,
Golden, CO 80401.
IGWMC Key: 6312 Model Name: ODAST Released: 1985
Authors: I. Javandel, C. Doughty and C.F. Tsang.
ODAST is an analytical solution to the one-dimensional convective-dispersive transport of a nonconservative
solute in a homogeneous, isotropic aquifer with a uniform flow field. The model includes decay at the solute
source and in the aquifer, and linear equilibrium adsorption. It calculates C/CO at any point downstream
from the contaminant source at any specified time and assumes zero background concentration.
Contact address: I. Javandel, Lawrence Berkeley Lab., Earth Sc. Div., Berkeley, CA 94720, or Intern.
Ground Water Modeling Ctr, Col. Sch. of Mines, Golden, CO 80401.
IGWMC Key: 6350 Model Name: WALTON35 Released: 1985
Author: W.C. Walton
WALTON35 is a package containing a series of simple BASIC programs for simulating flow, solute transport,
and heat transport in various types of aquifers. The programs are based on analytical and numerical
solutions of the governing equations. Included are various analytical solutions for non-conservative solute
transport in a homogeneous aquifer. The programs are interactive, simple to use, and easy to modify.
Contact address: Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401
C.1.-1-9
-------
Appendix C.I, part 1 (continued)
IGWMC Key: 6351 Model Name: WELFUN/WELFLO/CONMIG Released: 1989
Author: W.C. Walton
The programs WELFUN, WELFLO and CONMIG calculate common well function values and simulate a wide
range of ground-water flow and contaminant migration situations based on analytical solutions. The
program options include: (1) drawdown or recovery due to multiple production and/or injection wells with
variable discharge or recharge rates, drains, and mines; (2) confined, leaky confined, and water table
conditions with barrier and/or recharge boundaries and discontinuities; and (3) development of localized
contaminant plumes from slug or continuous source areas of various shape and sizes due to advection,
dispersion, retardation caused by linear adsorption, and radioactive decay.
Contact address: Lewis Publ. Inc., 2000 Corporate Blvd., N.W. Boca Raton, FL 33431
IGWMC Key: 6380 Model Name: SOLUTE Released: 1991
Author: M.S. Beljin
SOLUTE is an interactive program of eight analytical solutions for conservative and non-conservative solute
transport in saturated ground-water systems. The solutions vary according to dimensionality, type of source
and initial and boundary conditions. The package includes screen graphics.
Contact address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6590 Model Name: BEAVERSOFT Released: 1987
Authors: J. Bear and A. Verruijt
BEAVERSOFT is a package of analytical and numerical solutions for ground-water flow and solute transport.
It includes programs for steady and non-steady state two-dimensional flow in heterogeneous aquifers, for
flow through dams and for conservative and non-conservative advective-dispersive transport of pollutants.
Contact address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 6600 Model Name: CATTI Released: 1988
Authors: J.P. Sauty and W. Kinzelbach
CATTI (Computer Aided Tracer Test Interpretation) is a program for the interpretation of tracer test data
based on an analytical solution of the nonconservative advective-dispersive solute transport equation. It
computes breakthrough curves based on instantaneous or continuous injection of tracer into a
homogeneous aquifer with either 1D-2D uniform flow or axisymmetric flow for 1 or 2 layers. CATTI allows
interactive modification of transport parameters and immediate visualization of breakthrough curves. The
program is also capable of automatic parameter identification by non-linear least-squares estimation
methods.
Contact address: Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401
C.1.-1-10
-------
Appendix C.1, part 1 (continued)
IGWMC Key: 6601 Model Name: EPA-VHS Released: 1989
Author: P.K.M. van der Heijde
EPA-VHS (Vertical-Horizontal Spread model) is an analytical solute transport model to predict maximum
concentration of a pollutant at a prescribed distance downstream from a continuous source (compliance
point). It is based on a solution for the transport of a conservative constituent in a homogeneous, isotropic
aquifer with one-dimensional, horizontal steady-state flow and dispersion perpendicular to the flow path.
The model assumes zero retardation, a continuous input at maximum extraction levels, and saturated soil
conditions. This program contains two versions: (1) the original VHS model as published by Domenico and
Palciauskas (1982), and (2) the modified EPA version as published in the Federal Register, Nov. 27, 1985.
Contact address: Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 6660 Model Name: CRACK Released: 1988
Author: E.A. Sudicky
The CRACK package contains 4 analytical models for mass transport in fractured porous media: (1)
transport in a single fracture including matrix diffusion with and without dispersion along fracture axis
(models CRACKD and CRACKDO, respectively); (2) transport in a system of parallel fractures including matrix
diffusion with no dispersion along fracture axis (PCRACKO); (3) and transport in a single fracture with matrix
diffusion and radial diverging flow (RCRACK). The package includes a plotting routine for concentration vs.
time at different locations or concentration vs. position for different times (PLOTC).
Contact address: Waterloo Center for Groundwater Research, Univ. of Waterloo, Waterloo, Ontario,
Canada N21 3G1
IGWMC Key: 6700 Model Name: MYGRT Released: 1989
Authors: K.V. Summers, S.A. Gherini, M.M. Lang, M.J. Ungs, et al.
MYGRT is an interactive, menu-driven microcomputer code to predict the migration of both inorganic and
organic solutes through the saturated ground-water zone, downgradient of sources such as waste disposal
sites or spills. The processes included are advection, dispersion, retardation and decay. The code is based
on analytical solutions and can simulate problems in one or two dimensions using either horizontal or
vertical views. The code includes various options for tabular and graphic display of the results.
Contact address: Electric Power Res. Inst., Software Center, 1930 Hi Line Drive, Dallas, TX 75207
C.1.-1-11
-------
Appendix C.1: Solute Transport; Analytical Models For Saturated Zone, Part 2: Usability and
Reliability
IGWMC
Key
2037
2080
2810
3380
3432
4082
4620
4740
4911
5024
5055
5174
5175
5210
5211
5212
5242
5243
5245
Model
FRACSOL
GETOUT
WASTE
GRDFLX
CXTFIT
LAYFLO
MASCOT
SURMF
OASIS
PATHRAE
PLUME
FRACQUAL
POLLUT
PULSE
CXPMPM
TDPLUME/
TWOPLME
BLOB3D
CRAFLUSH
HPATCH3D
Usability
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U
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Y
Y
Y
Y
Y
Y
Sample Problems
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
U
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N
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KEY: Y = YES N = NO L = LIMITED M = MANY F = FEW U = UNKNOWN
C.I-2-1
-------
Appendix C.1, part 2 (continued)
IGWMC
Key
5246
5247
5248
5310
6011
6020
6024
6100
6120
6220
6227
6250
6310
6311
6312
6350
6351
Model
LINE2D
PATCH3D
SUPER1D
PRZMAL
RWH
PLUME
PLUME2D
GROUND
AT123D
ONE-D
CFITIM
WELL
LTIRD
TDAST
ODAST
WALTON35
WELFUN/
WELFLO/
CONMIG
Usability
Preprocessor
U
U
U
U
Y
Y
Y
N
Y
N
N
N
N
N
N
Y
Y
Postprocessor
U
U
U
U
Y
Y
N
N
Y
N
N
N
N
N
N
N
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
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Problems
a
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Y
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U
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ire Dependency
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viewed Theory
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KEY: Y = YES N = NO L = LIMITED M = MANY F = FEW U = UNKNOWN
C.1-2-2
-------
Appendix C.1, part 2 (continued)
IGWMC
Key
6380
6590
6600
6601
6660
6700
Model
SOLUTE
BEAVERSOFT
CATTI
EPA-VHS
CRACK
MYGRT
Usability
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KEY: Y = YES N = NO L = LIMITED M = MANY F = FEW U = UNKNOWN
C.1-2-3
-------
Appendix C.2: Solute Transport; Two-Dimensional Numerical Models for Saturated Zone, Part 1:
Model Description
Note: Some two-dimensional models may also be used for simulation of one-dimensional systems or for
simulation of radial-symmetric problems; most models for dual porosity media may also be used
for simulation of regular porous media systems (see Appendix F); some transport models can
handle either solute transport or heat transport, or even both in a single simulation; there are some
one- and two-dimensional variably saturated models which may also be used for simulation of
systems under fully saturated conditions (see Appendix C.4).
IGWMC Key: 251 Model Name: WTQUAL1 Released: 1981
Authors: McWhorter, D.B., Sunada, O.K.
WTQUAL1 is a finite difference model for simulation of transient, two-dimensional horizontal flow and solute
transport in confined, semi-confined or water-table aquifers with water quality problems caused by mining
activities or natural contamination.
Contact Address: Sunada, O.K., Colorado State Univ., Dept. of Civil Eng., Fort Collins, CO 80523
IGWMC Key: 588 Model Name: SEFTRAN Released: 1986
Authors: Huyakorn, P.S., Ward, D.S., Rumbaugh, J.O., Broome, R.W.
SEFTRAN (Simple and Efficient Flow and TRANsport model) is a concise finite element model to simulate
transient two-dimensional fluid flow and transport of non-conservative contaminants or heat in isotropic,
heterogeneous aquifers. It can solve the flow and transport equations in an areal plane, a vertical
cross-section, or an axisymmetric configuration. Line elements may be used to simulate discrete fractures
or rivers.
Contact Address: D.S. Ward , GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 680 Model Name: GWSIM-II Released: 1981
Author: Knowles, T.R.
GWSIM-II is a finite difference model for simulation of steady-state or transient, two-dimensional groundwater
flow and conservative solute transport in an anisotropic, heterogeneous, (leaky) confined or unconfined
aquifer. The model can handle a combination of confined and unconfined conditions. The uncoupled finite
difference equations for flow and transport are solved using the iterative alternating direction implicit (IADI)
method, together with Gauss elimination.
Contact Address: Texas Dept. of Water Resources, Texas Natural Resources Information System,
P.O. Box 13087. Austin, TX 78711
IGWMC Key: 740 Model Name: USGS-2D-TRANSPORT/MOC/KONBRED Released: 1989
Authors: Konikow, L.F., Bredehoeft, J.D.
MOC is a two-dimensional model for the simulation of non-conservative solute transport in heterogeneous,
anisotropic aquifers. It computes changes in time in the spatial concentration distribution caused by
convective transport, hydrodynamic dispersion, mixing or dilution from recharge, and chemical reactions.
The chemical reactions include first-order irreversible rate reaction (e.g. radioactive decay),
(continued )
C.2-1-1
-------
Appendix C.2, part 1 (continued)
USGS-2D-TRANSPORT - continued
equilibrium-controlled sorption with linear, Freundlich or Langmuir isotherms, and monovalent and/or
divalent ion-exchange reactions. MOC solves the finite difference approximation of the groundwater flow
equation using iterative ADI and SIP. It uses the method of characteristics followed by an explicit procedure
to solve the transport equation.
Contact Address: LF. Konikow, U.S. Geological Survey, Groundwater Branch WRD, 431 National
Center, Reston, VA 22092; or Internat. Ground Water Modeling Ctr., Colorado Sen.
of Mines, Golden, CO 80401.
IGWMC Key: 742 Model Name: MOCDENSE Released: 1992
Authors: Sanford, W.E., Konikow, LF.
MOCDENSE is a numerical model to simulate conservative (non-reactive) convective-dispersive solute
transport one or two constituents in groundwater where there is two-dimensional, cross-sectional,
density-dependent flow. The model is a modified version of the USGS two-dimensional solute transport
model MOC by Konikow and Bredehoeft, which uses a combination of the finite difference method and the
method of characteristics to solve the flow and transport equations. It solves for fluid pressure and solute
concentration. Density is a function of concentration of one of the constituents. The model is applicable
to situations where in addition of the density controlling species movement and concentration of another
dissolved species needs to be predicted.
Contact Address: LF. Konikow, U.S. Geological Survey, National Center, Reston, Virginia; or Internat.
Ground Water Modeling Ctr., Colorado Sen, of Mines, Golden, CO 80401.
IGWMC Key: 1010 Model Name: GGWP Released: 1983
Authors: Miller, I., Marlon-Lambert, J.
GGCP (Golder Groundwater Computer Package) is an integrated suite of computer programs for
steady-state or transient finite element simulation of two-dimensional, vertical or axisymmetric and
quasi-three dimensional flow and transport of reactive solutes in anisotropic, heterogeneous, multi-layered
aquifer systems. Auxiliary computer programs are included for semi-automatic mesh generation, input
preparation, and presentation of model results (contour and vector plots). Confined, leaky-confined and
unconfined flow problems are simulated with the programs AFPM (Aquifer Flow in Porous Media) and FPM
(Flow in Porous Media). They can handle a moving phreatic surface, evaporation, and interaction with
surface flows. The transport program (SOLTR) includes convection, dispersion, dilution, sorption and
radioactive decay.
Contact Address: Golder Associates . Inc.. 4104 148th Ave. NE, Redmond, WA 98052
IGWMC Key: 2120 Model Name: PATHS Released: 1980
Authors: Nelson, R.W., Schur, J.A.
The PATHS program is an idealized hybrid analytical/numerical model for simulation of steady-state or
transient, two-dimensional, saturated groundwater flow and transport processes of advection, sorption and
ion exchange. It includes an analytical solution of the flow equation and the Runge-Kutta solution for the
pathline equations and the effects of equilibrium ion-exchange and linear adsorption. The model calculates
pathlines, location/arrival time distribution, and location/outflow quantity distribution in a confined stratum
(continued )
C.2-1-2
-------
Appendix C.2, part 1 (continued)
PATHS - continued
that is isotropic and homogeneous. It assumes a uniform lateral flow gradient and superimposed leakage
from a vertical, cylindrical fully penetrating pond or cavern. The model can handle up to 35 fully penetrating
wells or vertical line sources.
Contact Address: Water & Land Resources Div., Battelle Pacific NW Laboratories, P.O. Box 999,
Richland, WA 99352
IGWMC Key: 2690 Model Name: RANDOM WALK/TRANS Released: 1981
Authors: Prickett, T.A., Naymik, T.G., Lonnquist, C.G.
RANDOM WALK/TRANS is a numerical model to simulate two-dimensional steady or transient flow and
transport problems in heterogeneous anisotropic aquifers under water table and/or confined or leaky
confined conditions. The model calculates heads, velocities and concentrations for transport processes of
advection, dispersion, diffusion, sorption and decay. Flow is simulated using a finite difference approach
and the resulting set of equations is solved with the iterative alternating direction implicit method. Advective
transport is solved with a particle-in-a-cell method, while the dispersion is analyzed with the random walk
method.
Contact Address: Illinois State Water Survey, P.O. Box 5050, Sta. A, Urbana, IL 61820; or Internal.
Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 3084 Model Name: CHNTRNS Released: 1987
Authors: Noorishad, J., Carnahan, C.L., Benson, LV.
CHMTRNS is a temperature-dependent non-equilibrium reactive chemical transport code, based on the
CHEMTRN code (Miller and Benson) developed in the early 1980's. Equations solved include mass balance,
aqueous species transport, non-equilibrium reactions, transport of hydrogen and hydroxide ions, equilibrium
complexation, dissolution and precipitation, ion exchange, redox reactions, and heat transport. The code
is capable of simulating kinetic calcite and silicate dissolution, irreversible glass dissolution, oxidation and
reduction, and stable carbon isotope fractionation during transport. The code can handle Neumann and
Dirichlet boundary conditions and includes a mesh generation scheme. The 1 -D transport equation is solved
using a upstream weighted finite difference algorithm.
Contact Address: Noorishad, J., Lawrence Berkeley Laboratory, Earth Sciences Division, Univ. of
Calif.. Berkeley. CA 94720
IGWMC Key: 3220 Model Name: GEOFLOW Released: 1982
Authors: Haji-Djafari, S., Wells, T.C.
GEOFLOW is a Galerkin finite element model to simulate steady or non-steady, groundwater flow and solute
mass transport in two-dimensional groundwater systems. The aquifer can be confined, semiconfined (leaky),
or unconfined and its properties can be anisotropic and heterogeneous. Multiple wells with time-dependent
flow rates can be specified. The model includes geochemical reactions such as adsorption, acid
neutralization, and radioactive decay. The model comes with a graphical postprocessor to produce
contours, velocity vectors, and isopachs.
Contact Address: D'Appolinia Waste Management Services, Inc., 10 Duff Road, Pittsburg, PA 15235
C.2-1-3
-------
Appendix C.2, part 1 (continued)
IGWMC Key: 3233 Model Name: PORFLOW - II (2D) Released: 1988
Author: Runchal, A.K.
PORFLOW II (2D) is an integrated finite difference model for analysis of coupled, steady-state or transient,
2-dimensional horizontal, vertical or radial, density dependent flow and heat and/or mass transport in
anisotropic, heterogeneous, non-deformable saturated porous media with time dependent aquifer and fluid
properties. User interface is based on the FREEFORM language with simple English commands.
Contact Address: Analytic & Computational Research, Inc., 1931 Stradella Road, Bel Air, CA 90077
IGWMC Key: 3376 Model Name: FEMA Released: 1985
Authors: Yeh, G.T., Huff, D.D.
FEMA (Finite Element model of Material transport through Aquifers) is a two-dimensional finite element
model for simulation of solute transport in heterogeneous, anisotropic porous media. The
advective-dispersive transport model includes radioactive decay, sorption and biological and chemical
degradation, consolidation, and natural and artificial sources and/or sinks. The model grid may include both
quadrilateral and triangular elements. FEMA solves the solute transport equation only, requiring the velocity
field to be generated by the accompanying flow model FEWA.
Contact Address: Yeh, G.T. , Penn State University, Dept. of Civil Eng., 225 Sackett Building,
University Park, PA 16802.
IGWMC Key: 3378 Model Name: AQUITRAN Released: 1989
Authors: Yeh, G.T., Francis, C.W.,
AQUITRAN is a two-dimensional, vertically averaged solute transport model based on an
orthogonal-upstream weighing finite element scheme, which results in a matrix amenable to successive
over-relaxation (SOR) solution strategies. The model considers advection, dispersion, sources/sinks,
first-order decay, and linear equilibrium adsorption. The model needs a hydraulic head distribution as
generated by the complementary model AQUIFLOW by Yeh (1984). The set of weighing functions are
developed for line, quadrilateral and triangular elements. For large problems, when SOR iteration must be
employed to solve the matrix equation, the orthogonal-upstream weighing scheme provides the only scheme
resulting in convergent SOR computations for all Peclet numbers.
Contact Address: Oak Ridge National Laboratory, Environm. Sciences Div., Oak Ridge, TN 37831
IGWMC Key: 3610 Model Name: CHEMTRN/THCC Released: 1986
Authors: Miller, C.W., Benson, LV., Carnahan, C.L
CHEMTRN is a one-dimensional simulation of advective-drffusive-dispersive transport of a reactive chemical
in a saturated porous medium by simultaneously solving the mass action, transport and site constraint
equations. Sorption is modeled by ion exchange and surface complexation. The code allows precipitation
and dissolution processes. The activity coefficient is computed by Davies equation. THCC is a modified
version of CHEMTRN including redox reactions. THCC uses a one-step algorithm to incorporate chemical
reactions directly into the chemical transport equations and solve then simultaneously.
Contact Address: Lawrence Berkeley Laboratory, Earth Sciences Division, Berkeley, CA 94720
C.2-1-4
-------
Appendix C.2, part 1 (continued)
IGWMC Key: 3790 Model Name: PORFLO Released: 1985
Authors: Runchal, A.K., Sagar, B., Baca, R.G., Kline, N.W.
PORFLO is an integrated finite difference model for transient two-dimensional or axisymmetric simulation
of coupled buoyancy driven groundwater flow, heat transfer and radionuclide transport in layered geologic
systems. Heat transfer processes include storage, advection, conduction, dispersion and heat generation.
Fluid flow processes include storage, inflows and outflows, pore pressure buildup, buoyancy driving force
and temperature dependent hydraulic conductivity. Density is a function of concentration. Mass transport
processes can handle multi-phase conditions and include storage, advection, dispersion, diffusion, sorption,
retardation, dissolution, decay, and mass release.
Contact Address: N.W. Kline, Boeing Computer Services Richland, P.O Box 300, Richland, WA 99352
IGWMC Key: 3831 Model Name: SATRA-CHEM Released: 1986
Authors: Lewis, F.M., Voss, C.I., Rubin, J.
SATRA-CHEM is a hybrid Galerkin finite-element and integrated finite difference model for simulation of
horizontal or cross-sectional two-dimensional flow and multi-solute transport in fully saturated porous media.
The constant-density model is a modification of the USGS' SATRA model, which in itself is a simplified
version of SUTRA. SATRA-CHEM incorporates equilibrium controlled reactions: (1) linear sorption and up
to two aqueous complexations, and (2) binary ion-exchange and a single complexation reaction involving
one of the exchanging species. The time derivative is approximated using a backwards finite-difference
scheme.
Contact Address: U.S. Geological Survey, WATSTORE Program Office, 437 National Center, Reston,
VA 22092
IGWMC Key: 3868 Model Name: MAST-2D Released:-
Author: Desai, C.S.
MAST-20 is a finite element solution of the coupled two-dimensional transient seepage and
convective-dispersive mass transport equations for a saturated porous media. The coupling occurs through
changes in density of the liquid with time as a function of concentration. The model, applicable to
two-dimensional cross-sectional problems, uses quadrilateral 4-node elements with bilinear variation of
concentration, fluid pressure and two components of velocity. The assemblage equations are solved using
a Crank-Nicolson scheme. The model has been designed for analysis of density-varying transport problems
such as saltwater intrusion and pollutant transport.
Contact Address: Desai, C.S., University of Arizona, Department of Civil and Mechanical Engineering,
Tuscon, AZ 85721
IGWMC Key: 3940 Model Name: RESSQ Released: 1985
Authors: Javandel, I., Doughty, C., Tsang, C.F.
RESSQ is a semi-analytical model of 2-dimensional contaminant transport that calculates the streamline
pattern in an aquifer, the location of contaminant fronts around sources at specified times, and concentration
versus time at sinks. RESSQ assumes a homogeneous, isotropic confined equifer of uniform thickness and
(continued )
C.2-1-5
-------
Appendix C.2, part 1 (continued)
RESSQ - continued
a steady-state regional flow field. It can handle advection and linear equilibrium adsorption. Sources are
represented by fully penetrating recharge wells and ponds, and sinks are represented by fully penetrating
pumping wells.
Contact Address: Javandel, I., Lawrence Berkeley Laboratory, Earth Sciences Division, University of
California, Berkeley, CA 94720; or Internat. Ground Water ModelingCtr, Colorado
Sch. of Mines, Golden, CO 80401.
IGWMC Key: 4320 Model Name: SOTRAN Released: 1983
Authors: Nwaogazie, I.L
SOTRAN is a finite element solute transport model for two-dimensional unconfined aquifer systems using
linear or quadratic isoparametric quadrilateral elements and including linear equilibrium adsorption, first-order
biodegradation and radio-active decay.
Contact Address: Nwaogazie, I.L., University of Port Harcourt, Department of Civil Engineering, PMB
5323 Port Harcourt, Nigeria
IGWMC Key: 4360 Model Name: IONMIG Released: 1984
Authors: Russo, A.J.
IONMIG is a finite difference model to calculate two-dimensional far-field convective-diffusive transport of
decaying radionuclides through a saturated porous medium. Nuclide adsorption coefficient is a function
of concentration and temperature. Planar or axisymmetric two-dimensional geometries can be treated with
either explicit or implicit solvers. The model requires for input temperature and velocity distributions as
generated by the related code MARIAH.
Contact Address: Russo, A.J., Sandia National Laboratories, Fluid Mechanics and Heat Transfer Div.
1512, Albuquerque, NM 87185
IGWMC Key: 4450 Model Name: TRANQL/MICROQL Released: 1985
Authors: Cederberg, G.A., Street, R.L, Leckie, J.O.
TRANQL is a finite element transport model for simulation of multi-component solute transport with
equilibrium interaction chemistry coupled with one-dimensional advective-dispersive finite element transport.
Significant equilibrium reaction such as complexation, ion exchange, competitive adsorption, and
dissociation of water may be included. It includes to models for ion-exchange, the constant capacity model
and the triple-layer model. The model has been applied to cadmium, chloride, and bromide transport in a
one-dimensional column.
Contact Address: G.A. Cederberg, 2305 A 37th Street, Los Alamos, NM 87544
C.2-1-6
-------
Appendix C.2, part 1 (continued)
IGWMC Key: 4694 Model Name: SAFTMOD Released: 1988
Authors: Huyakorn, P.S., Buckley, J.E.
SAFTMOD is a finite element model for simulating flow and solute transport in the saturated zone of an
unconfined groundwater system. It performs two-dimensional simulations in either the X-Y or X-Z plane of
the porous medium. It also can perform axisymmetric simulations. Both single and leaky two-aquifer
systems can be handled with recharge from infiltration or precipitation and well pumping or injection.
Transport include hydrodynamic dispersion, advection, linear equilibrium sorption, and first-order decay.
Parent/daughter transformations are also simulated. Boundary conditions include prescribed head,
volumetric water flux, concentration, and solute mass flux.
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite #900, Herndon, VA 22070
IGWMC Key: 4910 Model Name: BIOPLUMEII Released: 1987
Authors: Rifai, H.S., Bedient, P.B., Bordon, R.C., Haasbeek, J.F.
BIOPLUME II is a two-dimensional solute transport model to compute changes in concentration over time
due to advection, dispersion, mixing, and retardation. The model simulates the transport of dissolved
hydrocarbons under influence of oxygen-limited biodegradation. It also simulates reaeration and anaerobic
biodegradation as a first order decay in hydrocarbon concentrations. BIOPLUME II is based on the USGS
2D solute transport model MOC (Konikow-Bredehoeft). It solves the transport equation twice: once for
hydrocarbon and once for oxygen. The model assumes an instantaneous reaction between oxygen and
hydrocarbon. It can simulate natural biodegradation processes, retarded plumes, and in-situ bioremediation
schemes.
Contact Address: H.S. Rifai, Rice University, Dept. of Environm. Sciences and Eng., P.O. Box 1892,
Houston, Texas 77251; EPA/CSMoS, or IGWMC.
IGWMC Key: 4911 Model Name: OASIS Released: 1989
Authors: Newell, C.J., Haasbeek, J.F., Hopkins, L.P., Alder-Schaller, S.E. et Al.
OASIS is a graphical decision support system for groundwater contamination modeling developed for the
Macintosh II or SE personal computer using HyperCard software. OASIS is a collection of computer tools
including extensive computerized documentation, two chemical databases, a hydrogeologic database
derived from a survey of 400 sites across the US and DRASTIC aquifer vulnerability index system, a
numerical 2-dimensional solute transport and biodegradation model -BIOPLUME II--, and an analytical solute
transport model -ODAST. It includes extensive graphical pre- and postprocessing for BIOPLUME II. OASIS
provides graphical and analytical support to decision makers and technical support personnel. See also
remarks.
Contact Address: P.B. Bedient, Rice University, Dept. of Environm. Sciences and Eng., P.O. Box
1892, Houston, Texas 77251-1892
IGWMC Key: 4930 Model Name: TARGET-2DH Released: 1985
Authors: Moreno, J.L, Asgian, M.I., Lympany, S.D., Pralong, P-J. et al.
TARGET-2DH is one of five models of the TARGET series (Transient Analyzer of Reacting Groundwater and
(continued )
C.2-1-7
-------
Appendix C.2, part 1 (continued)
TARGET-2DH - continued
Effluent Transport). It simulates two-dimensional, vertically averaged, confined and unconfined transient
groundwater flow and solute transport in a single heterogeneous, anisotropic aquifer using a hybrid finite
difference method. The transport is based on the solution of the advective-dispersive transport equation for
a single non-conservative contaminant with linear equilibrium adsorption (retardation). The solution method
used is based on an iterative alternating direction implicit method.
Contact Address: Dames & Moore, 1125 17th Str., #1200, Denver, CO 80202
IGWMC Key: 4932 Model Name: TARGET-2DM Released: 1985
Authors: Moreno, J.L, Asgian, M.I., Lympany, S.D., Pralong, P-J. et al.
TARGET-2DM is one of five models of the TARGET series (Transient Analyzer of Reacting Groundwater and
Effluent Transport). It simulates quasi-three dimensional, confined and unconfined transient groundwater
flow and solute transport in a multi-layered heterogeneous, anisotropic aquifer/aquitard system using a
hybrid finite difference method. The transport is based on the solution of the advective-dispersive transport
equation for a single non-conservative contaminant with linear equilibrium adsorption (retardation). The
solution method used is based on an iterative alternating direction implicit method.
Contact Address: Dames & Moore, 1125 17th. Str., #1200, Denver, Colorado 80202
IGWMC Key: 5018 Model Name: AQUA Released: 1991
Authors: Kjaran, S.P., Egilson, D., Sigurdson, S.Th.
AQUA is a program package developed for solving steady-state and transient two-dimensional ground-water
flow and transport problems using the finite element method. The model can be applied to either confined
or unconfined aquifers allowing for heterogeneity and anisotropy of aquifer hydraulic parameters and
time-varying infiltration and pumping. Processes included in the simulation of transport of heat and
dissolved chemicals are convection, decay, adsorption and velocity dependent dispersion. For heat
transport conduction is included. The AQUA package includes various graphic pre- and post processors
facilitating interactive grid design and data entry for area! and cross-sectional problems.
Contact Address: Vatnaskil Consulting Engineers, Armuli 11, IS-108 Reykjavik, Iceland; or Scientific
Software, Washington D.C.
IGWMC Key: 5120 Model Name: FEMSEEP Released: -
Author: Meiri, D.
FEMSEEP is a 2-D finite element flow and solute transport model, combined with particle tracking for solving
steady state and transient planar and cross-sectional groundwater flow in heterogeneous, anisotropic
aquifers. The aquifer can be under confined, unconfined or leaky confined conditions. The flow model can
be solved in terms of hydraulic head, drawdown, or stream function. Flow b.c.'s may include prescribed
head, prescribed flux, or mixed head-flux. The solute transport model accounts for advection, dispersion,
and retardation. Transport b.c.'s may have prescribed concentrations or mass flux. FEMSEEP supports
a movable grid for cross-sectional phreatic surface simulation and includes a preprocessor for grid design
and data preparation and a graphic postprocessor.
Contact Address: D. Meiri, Ebasco Environmental, 111 N. Canal Street, Chicago, IL 60606, or
Sceintific Software, Washington, D.C.
C.2-1-8
-------
Appendix C.2, part 1 (continued)
IGWMC Key: 5244 Model Name: CFEMTRAN Released: --
Authors: --
CFEMTRAN is a Galerkin finite element model for simulating 2-dimensional, transient solute transport in
cross-section. It computes solute concentration distribution by solving the advection-dispersion equation.
The program includes a mesh generation option for rectangular grids. It can also read manually generated
grid data. The groundwater velocities are element-wise variable and can be read directly from a FLONETS
output file. The model can handle solute decay and retardation. The matrix solution is by Cholesky
decomposition.
Contact Address: Waterloo Centre for Groundwater Research, University of Waterloo, Waterloo,
Ontario, Canada N2L 3G1
IGWMC Key: 5270 Model Name: MADPD Released: 1988
Authors: Syriopoulou, D., Koussis, A.O.
MADPD (Matched Artificial Dispersivrty - Principal Direction Method) is a two-dimensional finite difference
model for solute transport in saturated, steady groundwater flow systems with a known pore velocity
distribution. The model is tailored to advection-dominated conditions. The methodology combines the
Principal Directions of transport formulation with a fractional time stepping algorithm that incorporates a
highly efficient advection-dispersion step. The code can accommodate space-variable geohydrological
parameters, sources of time-varying strength distributed on entry boundaries, and solute undergoing
first-order decay and linear adsorption. The model can use one- or two-dimensional grids and cartesian or
curvilinear coordinates.
Contact Address: Koussis, A.D., Vanderbilt University, Dept. of Civil and Environm. Eng., Nashville,
TN 37235
IGWMC Key: 5330 Model Name: CANSAZ (EPACMS) Released: 1989
Authors: -
EPA's CANSAZ (Combined Analytical-Numerical Saturated Zone model) was developed to simulate the
migration of contaminants beneath surface impoundments where hydraulic mounding occurs. The model
combines an analytical solution for two-dimensional steady-state ground-water flow, coupled with both an
analytical and a numerical three-dimensional contaminant transport model. It includes the monte carlo
technique to account for uncertainty in parameter distribution. It was meant for use in the development of
national regulation under RCRA. It should not be used for site-specific application.
Contact Address: Z. Saleem, U.S. Environmental Protection Agency, Office of Solid Waste (OS-331),
401 M Str. S.W., Washington, D.C. 20460
IGWMC Key: 5530 Model Name: SANDWICH Released: 1985
Authors: P.S. Huyakorn et al.
SANDWICH is a 3D finite-element model for analyzing groundwater flow and contaminant transport in
(continued )
C.2-1-9
-------
Appendix C.2, part 1 (continued)
SANDWICH - continued
multi-layered confined/unconfined aquifer systems. The model is designed to simulate fluid flow and solute
transport in fully-saturated porous media. Matrix assembly is performed in a horizontal slice-by-slice manner
to improve efficiency. The model employs a combination of rectangular and triangular elements. Coupling
of aquifer and aquitards is handled using a convolution integral to evaluate leakage fluxes and incorporate
these fluxes into the matrix system. For aquifers comprised of several nodal sublayers, the matrix solution
for each aquifer is performed using a two-stage algorithm, the Alternate sublayer And Line Sweep (ALALS)
procedure.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza # 100, Sterling, VA 22170
IQWMC Key: 5732 Model Name: MASS Released: -
Authors: van Tender, G., van Rensburg, H.J.
MASS is a two-dimensional triangular finite element model which solves the groundwater flow equation for
a confined aquifer and the advective-dispersive solute transport equation for a conservative contaminant.
It includes the program GEMASS, a simple mesh generator program for MASS.
Contact Address: van Rensburg, H.J., Dept. of Water Affairs, Private Bag X313, Pretoria, South Africa
IGWMC Key: 5780 Model Name: POSSM/MCPOSSM Released: -
Authors: -
POSSM (PCB On-Site Spill Model) is a computer code representing the PCB Spill Exposure Assessment
Methodology, a quantitative framework for estimating general public exposure levels associated with spills
from electric utility equipment. POSSM is a chemical transport and fate model capable of considering such
processes as volatilization, leaching to ground water and chemical washoff from a land surface due to
runoff /erosion. On-site environmental concentrations can be estimated with POSSM; off-site concentrations
with simple transport and fate models, PTDIS (for air), RIVLAK (for surface water) and GROUND (for ground
water), all part of the methodology. MCPOSSM puts the POSSM model in a monte carlo framework to
estimate uncertainties of chemical levels associated with spills.
Contact Address: Electric Power Research Inst., Off. of Commercial and Business Developm., P.O.
Box 10412, Palo Alto, CA 94303
IGWMC Key: 5861 Model Name: TWODIMPL Released: 1988
Authors: Lindstrom, F.T., Boersma, L
TWODIMPL is a linear, two-dimensional quasi-analytical model for advective-dispersive transport of reactive
chemicals leaking into a rectangular-shaped confined aquifer from constant strength sources, emitting
uniformly across the finite vertical aquifer thickness. Linear equilibrium rates are assumed to apply to
reversible sorbing soil components made up of weakly sorbing and strongly sorbing fractions and organic
matter. First- or zero-order loss rates due to microbial or other irreversible loss processes are included.
Irregularly shaped sources are approximated by an assembly of maximum 25 constantly emitting rectangular
source regions. The equation is solved using Green's function approach, resulting in a time convolution
integral for the concentration distribution.
Contact Address: SEA, Inc., Corvallis, Oregon
C.2-1-10
-------
Appendix C.2, part 1 (continued)
IGWMC Key: 6354 Model Name: GWTR3D Released: 1989
Author: Walton, W.C.
GWT3D is a random walk model for simulation of contaminant transport in a heterogeneous, anisotropic
confined, leaky-confined, or water-table aquifer. It uses a particle-in-a-cell method to solve for advective
transport and the random walk technique for the dispersion mechanism. The model requires a
pre-calculated or measured head distribution. It can handle linear adsorption and single-component
radio-active decay. It allows for a wide variety of source types and source geometry.
Contact Address: Lewis Publishers, Inc. c/o CRC Publishers, Inc., 2000 Corporate Blvd. N.W., Boca
Raton, FL 33431
IGWMC Key: 6603 Model Name: ASM Released: 1991
Authors: Kinzelbach, W., Rausch, R.
ASM (Aquifer Simulation Model) is a menu-driven numerical model for steady-state or transient groundwater
flow and (uncoupled) solute transport. The two-dimensional block-centered finite difference equations for
(leaky-)confined or unconfined flow are solved using either the IADI or PCG method. Pathlines and
isochrones around pumping well are computed by point-tracking in the velocity filed using Euler integration.
Solute transport is simulated by the random walk method based on the Ito-Fokker-Planck theory. The model
can simulate variable well rates, constant flux and constant head boundaries, and constant or instantaneous
contaminant sources. It includes various graphic display option to view the simulation results.
Contact Address: W. Kinzelbach, Gesamthochschule Kassel-Universitat, FB 14, Morftzstr. 21, D-3500
Kassel, Germany; or Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines,
Golden, CO 80401.
IGWMC Key: 6770 Model Name: CUMOC/MIKERN Released: 1988
Authors: Illangasekare, T.H., Doll, P.
CUMOC/MIKERN is a two-dimensional solute transport model for water-table aquifers using a discrete kernel
approach for flow and a method-of-characteristics approach for solute transport. The MOC method has
been improved by using an influence area particle tracking scheme that avoids oscillations and step jumps
of breakthrough curves. The transport model includes advection, dispersion, linear equilibrium sorption and
the influence of immobile zones. The model is designed to simulate sources, sinks and the effects of varying
saturated thickness. Biodegradation and radioactive decay are described as first-order reactions. The
model handles sorption hysteresis and different rates for decay of solute and sorbed species.
Contact Address: T.H. Illangasekare, Dept. of Civil and Environm. Eng., Univ. of Colorado, Boulder,
CO 80309
C.2-1-11
-------
Appendix C.2: Solute Transport; Two-Dimensional Numerical Models For Saturated Zone, Part 2:
Usability and Reliability
IGWMC
Key
251
588
680
740
742
1010
2120
2690
3084
3220
3233
3376
3378
3610
3790
3831
3868
3940
4320
Model
WTQUAL1
SEFTRAN
GWSIM-II
USGS-2D-
TRANSPORT/
MOC/ KONBRED
MOCDENSE
GGWP
PATHS
RANDOM WALK/
TRANS
CHNTRNS
GEOFLOW
PORFLOW-II
FEMA
AQUITRAN
CHEMTRN/
THCC
PORFLO
SATRA-CHEM
MAST-2D
RESSQ
SOTRAN
Usability
Preprocessor
U
Y
N
Y
Y
Y
N
Y
U
Y
Y
N
N
N
Y
N
U
Y
U
Postprocessor
U
U
N
Y
N
Y
N
Y
U
Y
Y
N
N
N
Y
N
U
Y
U
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
U
N
N
N
N
Y
N
N
U
Y
Y
N
N
U
Y
N
U
N
N
o
a
a
CO
L
N
N
Y
L
L
N
L
U
U
Y
L
L
U
L
L
U
L
N
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Peer Reviewed Coding
U
U
U
Y
U
U
U
Y
U
U
U
U
U
U
U
U
U
Y
U
Verified
L
L
L
E
L
L
L
E
U
L
E
L
L
U
L
L
U
L
L
Field Tested
U
L
L
L
U
U
N
L
U
U
L
U
U
U
U
U
U
N
U
0
a
'o
•a
o
5
U
F
F
M
F
U
M
M
U
U
M
F
F
U
F
U
U
M
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.2-2-1
-------
Appendix C.2, part 2 (continued)
IGWMC
Key
4360
4450
4694
4910
4911
4930
4932
5018
5120
5244
5270
5330
5530
5732
5780
5861
6354
Model
IONMIG
TRANQL/
MICROQL
SAFTMOD
BIOPLUME II
OASIS
TARGET-2DH
TARGET-2DM
AQUA
FEMSEEP
CFEMTRAN
MADPD
CANSAZ (EPA-
CMS)
SANDWICH
MASS
POSSM/
MCPOSSM
TWODIMPL
GWTR3D
Usability
Preprocessor
U
U
Y
Y
Y
Y
Y
Y
Y
U
U
U
U
U
U
U
Y
Postprocessor
U
U
Y
Y
Y
Y
Y
Y
Y
U
U
U
U
U
U
U
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Hardware Dependency
U
U
Y
N
Y
Y
Y
Y
Y
U
U
U
N
Y
U
U
Y
r
o
Q.
Q.
w
U
U
L
L
L
Y
Y
Y
Y
U
U
U
N
L
U
U
L
Reliability
Peer Reviewed Theory
U
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Peer Reviewed Coding
U
U
U
u
N
N
N
U
U
N
U
U
U
U
U
U
Y
Verified
U
U
L
E
E
L
L
L
L
L
L
U
L
L
L
U
L
Field Tested
U
U
U
L
L
U
U
U
U
U
u
u
u
u
U
U
L
<5
»
i
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u
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u
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F
M
M
M
U
U
U
U
U
U
U
U
M
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.2-2-2
-------
Appendix C.2, part 2 (continued)
IGWMC
Key
6603
6770
Model
ASM
CUMOC/
MIKERN
Usability
S
»
u
1
Y
U
2
10
8
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Y
U
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a
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I
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1
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KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.2-2-3
-------
Appendix C.3: Solute Transport; Three-Dimensional Numerical Models for Saturated Zone, Part 1:
Model Description
Note: Many three-dimensional models may also be used for simulation of one- and two-dimensional
systems; most three-dimensional models for dual porosity media may also be used for simulation
of regular porous media systems (see Appendix F); there are some three-dimensional variably
saturated models which may also be used for simulation of systems with fully saturated conditions
(see Appendix C.4).
IGWMC Key: 515 Model Name: PTC Released: 1986
Authors: Babu, O.K. , Pinder, G.F., Niemi, A., Ahlfield, D.P.
PTC (Princeton Transport Code) is a three-dimensional model for simulation of uncoupled transient flow and
solute transport in confined or unconfined porous media. The model solves the advective-dispersive
transport equation for reactive and non-reactive solutes using a hybrid finite element Galerkin technique
coupled with a finite difference scheme. The FEM formulation is applied to the horizontal slices, and the
FDM to the cross-sections.
Contact Address: G.F. Pinder, University of Vermont, 101 Votey Building, Burlington, Vermont 05405
IGWMC Key: 582 Model Name: GREASE Released: 1982
Author: Huyakorn, P.S.
GREASE 2 is a multi-purpose finite element model to simulate transient, multi-dimensional, saturated
groundwaterflow, solute and /or energy transport in fractured and non-fractured, anisotropic, heterogeneous,
multilayered porous media. The analysis can be performed for confined, semiconfined, or unconfined
groundwater reservoir systems. Fluid leakage or heat transfer between the aquifer and its confining layer
can be taken into account. The model allows for analysis of areal flow, vertical cross-sectional flow or flow
in an axisymmetric configuration. Coupled thermal fluid flow capability, and density dependent flow and
solute transport capability area also available. Sorption and decay can be included in the solute transport
analysis.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 692 Model Name: SWIP/SWIPR/DWDM Released: 1985
Authors: INTERA Environm. Consult, Inc.
SWIP/SWIPR (Survey Waste Injection Program-Revised) or DWDM (Deep Well Disposal Model) is a finite
difference model to simulate unsteady, coupled three-dimensional groundwater flow, heat transport and
non-conservative contaminant transport in an anisotropic, heterogeneous aquifer. The model has been
superseded by HST3D, SWENT, and the SWIFT series.
Contact Address: K. Kipp, U.S. Geological Survey, Box 25046, Mail Stop 411, Denver Federal Center,
Lakewood, CO 80225
C.3-1-1
-------
Appendix C.3, part 1 (continued)
IGWMC Key: 697 Model Name: SWENT Released: 1983
Authors: Lantz, R.B., Pahwa, S.B., RamaRao, B.S.
SWENT (Simulator for Water, Energy, and Nuclide Transport) is a finite difference model for simulation of
transient, multidimensional transport of fluid, energy, a single inert chemical species, and any number of
radionuclides in straight or branched chains, through a heterogeneous, anisotropic confined aquifer. Flow
and transport are coupled through density and viscosity. Salt dissolution and leaching can be simulated.
Aquifer porosity is treated as function of pressure. Individual processes or a combination of the processes,
including well bore flow, may be simulated using a number of boundary conditions. The model permits the
choice of backward or central difference approximations and either direct or SOR iterative methods may be
used for solving the matrix equations.
Contact Address: National Energy Software Center, Argonne National Laboratory, 9700 S. Cass
Avenue, Argonne, IL 60439.
IGWMC Key: 2070 Model Name: CFEST Released: 1987
Authors: Gupta, S.K., Kincaid, C.T., Meyer, P.R., Cole, C.R.
CFEST (Coupled, Fluid, Energy and Solute Transport) is a three-dimensional finite element model for
simulation of steady-state or transient, single-phase Darcian flow, and energy and solute transport in
anisotropic, heterogeneous, multi-layered aquifers. The code has the capability to model discontinuous and
continuous layering and time-dependent and constant sources/sinks. The partial differential equations for
pressure, temperature, and solute concentration are coupled with fluid density and viscosity, and used in
a Galerkin FEM (linear elements), sequential solution. The relationship between porosity and pore-pressure
is also accounted for. The model comes with various programs for data input, gridding and post-processing
including streamline generation and contouring. It has a restart option and data error checking.
CFEST has undergone extensive verification testing, among others, as part of the international HYOROCOIN
project. Many of the test problems and the CFEST performance for the tests have been published.
Contact Address: Cole. C.R.. Battelle Pacific NW Laboratories, P.O. Box 999, Richland, WA 99352
IGWMC Key: 2691 Model Name: RAND30 Released: 1990
Authors: Prickett, T.A., and D.H. Koch
RAND3D is an interactive three-dimensional solute transport model utilizing the random-walk algorithm. The
model calculates horizontal advective transport based on a four point interpolation of the velocity vectors.
Calculation of vertical transport is based on linear interpolation between the input vertical velocity vectors
at the top and bottom of each layer. RAND3D includes first-order decay and linear, reversible adsorption
(retardation). It calculates concentration distributions and solute concentration exiting the model at a sink.
Transient flow simulations may be simulated by inputting a series of velocity files. A preprocessor,
PREMOD3D, is available to use the output of MODFLOW as input and to create velocity vectors for the
RAND3D model.
Contact Address: Koch and Assoc., 3458 Ellicott Center Drive. # 101, Ellicott City. MD 21043
IGWMC Key: 3840 Model Name: SWIFT Released: 1982
Authors: Dillon, R.T., Cranwell, R.M., Lantz, R.B., Pahwa, S.B.
SWIFT (Sandia Waste-Isolation Row and Transport) is a three-dimensional finite difference model for
(continued )
C.3-1-2
-------
Appendix C.3, part 1 (continued)
SWIFT - continued
simulation of coupled, transient, density-dependent flow and transport of heat, brine, tracers or radionuclides
in heterogeneous, anisotropic, fractured, aquifers. Transport processes include advection, dispersion,
diffusion, sorption, decay, and leaching. Two-line SOR iterative or direct-ordered solution methods may be
utilized.
The SWIFT code has been based on the SWIP/SWIPR code developed in 1976 for the U.S. Geological
Survey and modified in 1979. SWIFT has been superseded by SWIFT II from Sandia National Laboratories
and by SWIFT III and SWIFT 386 from GeoTrans, Inc.
Contact Address: R.M. Cranwell, Sandia National Laboratories, Albuquerque, NM 87185, or National
Energy Software Center, Argonne National Laboratory, 9700 S. Cass Avenue,
Argonne, IL 60439.
IGWMC Key: 3841 Model Name: SWIFT II Released: 1987
Authors: Reeves, M., Ward, D.S., Johns, J.D., Cranwell, R.M.
SWIFT II is a three-dimensional finite difference model for simulation of steady-state or transient flow and
transport of fluid, heat, brine, and radionuclide chains in confined or unconfined (fractured) porous media.
The equations for fluid, heat, and brine are coupled by fluid density, fluid viscosity, and porosity. Both
dual-porosity and discrete-fractures might be considered. Only one-dimensional migration is permitted in
the rock matrix. The model includes a salt dissolution mechanism and a waste leaching algorithm.
Moreover, SWIFT II has a well-bore submodel and handles both radial and cartesian coordinates. Among
the many boundary conditions which can be used is a free phreatic surface condition.
In 1986, under contract to the U.S. Nuclear Regulatory Commission, GeoTrans, Inc. extended the SWIFT
code of 1981 to include: fractured media, enhanced free water surface and extended boundary conditions.
SWIFT II has been superseded by SWIFT III and SWIFT 386.
Contact Address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 3842 Model Name: SWIFT HI/SWIFT 386 Released: 1992
Author: Ward, D.S.
SWIFT/386 is a transient, fully three-dimensional model which simulates the flow and transport of fluid, heat
(energy), brine, and radionuclide chains in porous and fractured geologic media. The primary equations
for fluid, heat, and brine are coupled by fluid density, fluid viscosity, and porosity. Both Cartesian and
cylindrical coordinate systems may be used. For the fracture zone the model allows both dual-porosity and
discrete fractures. Migration within the rock matrix is characterized as a one-dimensional process. Aquifer
hydraulic characteristics may be heterogeneous and anisotropic under confined or unconfined conditions.
The model includes linear and nonlinear (Freundlich) isothermal equilibrium adsorption, hydrodynamic
dispersion, and diffusion.
Discretization is performed by the finite-difference method using centered or backward weighing in the time
and space domains. Matrix solution is performed either by Gaussian elimination or by two-line successive
over-relaxation. SWIFT/386 incorporates a run-time monitor to display the actions and numerical behavior
of on-going transport simulations. The IBM PC version handles between 10,000 and 30,000 finite difference
blocks.
(continued )
C.3-1-3
-------
Appendix C.3, part 1 (continued)
SWIFT 111/386 - continued
SWIFT HI/386 handles a variety of boundary conditions and source terms for both the porous and fractured
media including prescribed pressure (head), temperature, and brine concentration; prescribed flux of fluid
(water), heat, brine, or (nuclide) mass; wellbore injection/production submodel subject to pumping
constraints; aquifer influence function (i.e. Carter-Tracy infinite reservoir); waste leach radionuclide submodel
for waste repository nuclides and heat; and free (phreatic) surface with recharge.
SWIFT HI/SWIFT 386 is an extension of SWIFT II (IGWMC Key # 3842), which in turn is an update and
extension of SWIFT (Sandia Waste-Isolation Row and Transport; IGWMC Key # 3841), released in 1981.
Originally, refinements in user options, mapping facilities and auxiliary files were included. A postprocessing
program UNSWIFT allows direct interfacing with the SURFER contouring package.
Contact Address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 4610 Model Name: HST3D Released: 1991
Author: Kipp, Jr., K.L
The Heat- and Solute-Transport Program HST3D simulates ground-water flow and associated heat and
solute transport in three dimensions. The three governing equations are coupled through the interstitial pore
velocity, the dependence of the fluid density on pressure, temperature, and solute mass fraction. The
solute-transport equation is for only a single, solute species with possible linear-equilibrium sorption and
linear decay. The finite difference model handles a variety of boundary conditions for confined and
unconfined aquifer conditions including an approximate free surface. The matrix equations are solved by
either direct (Gaussian) elimination or by an iterative solver, using two-line successive overrelaxation.
Two techniques are available for solution of the finite-difference matrix equations in HST3D. One technique
is a direct-elimination solver, using equations reordered by alternating diagonal planes. The other is an
iterative solver, using two-line successive overrelaxation. A re-start option is available for storing
intermediate results and restarting the simulation at an intermediate time with modified boundary conditions.
Data input and output in HST3D may be in metric (SI) units or inch-pound units. Output may include tables
of dependent variables and parameters, zoned-contour maps, and plots of the dependent variables versus
time. HST3D is a descendent of the Survey Waste Injection Program (SWIP) of the U.S. Geological Survey.
Contact Address: K.L Kipp, Jr., U.S. Geological Survey, MS 413, Box 25046, Denver Federal Center,
Denver, CO 80225; Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines,
Golden, CO 80401; or Scientific Software Group, Washington, D.C.
IGWMC Key: 4631 Model Name: SWICHA Released: 1991
Authors: Huyakom, P.S., Andersen, P.F., Mercer, J.W., White Jr., H.O.
SWICHA is a three-dimensional finite element model for analyzing seawater intrusion in coastal aquifers.
The model is designed to simulate coupled variable density fluid flow and solute transport in fully-saturated
porous media. The model which can also handle quasi-three-dimensional conditions and axisymmetric
geometries, includes linear equilibrium adsorption and first-order decay. Matrix assembly is performed in
a vertical slice-by-slice manner and solved with a SSOR scheme. The model computes spatial and temporal
variations of piezometric head, groundwater flow pattern, and flow rates across specified boundaries. It also
(continued )
C.3-1-4
-------
Appendix C.3, part 1 (continued)
SWICHA - continued
computes concentration distributions and velocities and includes a full fluid flow and solute transport mass
balance scheme.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170, or Internal.
Ground Water Modeling Ctr., Colorado School of Mines, Golden, CO 80401.
IGWMC Key: 4700 Model Name: DSTRAM Current Released: 1988
Author: Huyakorn, P.S.
DSTRAM (Density-dependent Subsurface TRansport Analysis Model) is a three-dimensional finite-element
model that simulates coupled, density-dependent single-phase fluid flow and solute or energy transport in
saturated porous media. This model can perform steady-state or transient simulations in a cross-section,
an axisymmetric configuration, or a fully-3D model. The contaminant transport equation includes advection,
hydrodynamic dispersion, linear equilibrium adsorption, and first-order degradation. For heat transport
simulation, additional processes of heat conduction and storage in the fluid and rock matrix can also be
included. Nonlinearity resulting from density differences is handled via a Picard algorithm. The transport
equation is solved using upstream weighted residual. A separate mesh generator MESHGN is available.
Boundary conditions in DSTRAM include prescribed nodal values of the equivalent fresh-water head or
prescribed integrated nodal values of fluid volumetric fluxes. Boundary conditions for solute transport
include prescribed nodal values of solute mass fluxes. Boundary conditions for heat transport include
prescribed temperature and prescribed integrated nodal values of heat fluxes. Output include nodal values
for hydraulic head, Darcy velocities and flow rates, and nodal concentrations and temperatures.
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 100, Herndon, VA 22070
IGWMC Key: 4933 Model Name: TARGET-3DS Released: 1985
Authors: Moreno, J.L, Asgian, M.I., Lympany, S.D., Pralong, P-J. et al.
TARGET-3DS is one of five models of the TARGET series (Transient Analyzer of Reacting Groundwater and
Effluent Transport). It simulates three-dimensional, saturated, density-coupled, transient groundwater flow
and solute transport using a hybrid (integrated) finite difference method. The transport is based on the
solution of the advective-dispersive transport equation for a single non-conservative contaminant with linear
equilibrium adsorption (retardation). The solution method used is based on an iterative alternating direction
implicit method. It includes an internal routine for selecting backward, forward, or central differencing
schemes, based on the value of the local Peclet number and direction of flow.
Contact Address: Dames & Moore, 1125 17th. Sir., #1200, Denver, Colorado 80202
IGWMC Key: 4941 Model Name: DYNTRACK Released: 1992
Authors: Riordan, P.J., Schroeder, D.J., Harley, B.M.
DYNTRACK is a computer program for simulation of three-dimensional transport. It uses the heads
computed with the companion code DYNFLOW. DYNTRACK uses the same finite element grid
representation of aquifer geometry, flow field, and stratigraphy used for a particular application for the
(continued )
C.3-1-5
-------
Appendix C.3, part 1 (continued)
DYNTRACK - continued
DYNFLOW model. DYNTRACK can perform either simple particle tracking or can model three-dimensional
advective dispersive transport of non-conservative contaminants. The contaminant transport is based on
the random walk method for a statistically significant number of particles, each particle having an associated
weight, decay rate, and retardation rate. Dispersion is simulated by imparting a random deflection to each
particle in each time step and can be scale-dependent. DYNTRACK includes the option to use backtracking
for source identification.
Contact Address: B.M. Harley, Camp Dresser & McKee Inc., One Cambridge Center, Cambridge, MA
02142
IGWMC Key: 4970 Model Name: MT3D Released: 1992
Author: Zheng, C.
MT3D (Modular Transport in 3 Dimensions) is a three-dimensional contaminant transport model using a
hybrid method of characteristics. Two numerical techniques are provided for the solution of the
advective-dispersive reactive solute transport equation: the method of characteristics (MOC) and the
modified method of characteristics (MMOC). The MMOC method overcomes many of the traditional
problems with MOC, especially in 3D simulations, by directly tracking nodal points backwards in time and
by using interpolation techniques. MT3D selectively uses the MOC or the MMOC technique dependent on
the problem at hand. The transport model is so structured that it can be used in conjunction with any
block-centered finite difference flow model such as the USGS' MODFLOW model.
The MT3D code is distributed together with a version of the USGS flow model MODFLOW, including the
PCG2 solver.
Contact Address: C. Zheng, S.S. Papadopulos & Assoc., Inc., 7944 Wisconsin Avenue, Bethesda,
Maryland 20814, USA.
IGWMC Key: 5161 Model Name: INTERTRANS Released: -
Author: Voorhees, M.
INTERTRANS is an interactive three-dimensional solute transport model for calculation of travel times,
pathlines and concentration distribution in heterogeneous, anisotropic groundwater systems. The transport
model is based on the random-walk method, incorporating three-dimensional scale-dependent dispersion.
The model includes an option for three-dimensional reverse pathline tracking. It requires a known flow field,
either measured, generated with the model INTERSAT by the same author, or by MODFLOW. INTERTRANS
includes on-line plan view and cross-sectional mapping and contouring of results, and real time particle
movement.
Contact Address: ESE/Hydrosoft, Inc., 63 Sarasota Center Boulevard, #107, Sarasota, FL 34240
IGWMC Key: 5520 Model Name: FTWORK Released: 19909
Authors: Faust, C.R., Sims, P.N., Spalding, C.P., Andersen, P.F.
FTWORK is a three-dimensional, block-centered finite difference model for simulation of steady-state or
(continued )
C.3-1-6
-------
Appendix C.3, part 1 (continued)
FTWORK - continued
transient, non-coupled groundwater flow and solute transport in fully saturated, multi-layered, confined or
unconfined, porous hydrogeologic systems. Transport mechanisms include advection, hydrodynamic
dispersion, linear equilibrium isotherm adsorption, and radioactive decay. It provides for parameter
estimation of the steady state flow applications using a least-squares procedure. The model allows variable
grid spacing and approximation of layers that have irregular thickness and/or are not horizontal by using
deformed coordinate approximations. Boundary conditions include prescribed head and flux, and
head-dependent flux. The model provides a cumulative mass balance.
The major limitations of the FTWORK code are: 1) water density is independent of concentration, thus
seawater intrusion and brines cannot be simulated; 2) for water-table conditions, the free surface must not
be steep and resaturation of dry grid blocks cannot occur; and 3) treatment of dispersive processes is based
on uniform longitudinal and transverse dispersivity concepts. The program includes a subroutine which
allows linkage with the particle tracking program MODPATH.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, #100, Sterling, VA22170, or Internal. Ground
Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 5650 Model Name: 3D-MADPD Released: 1989
Authors: Koussis, A.D., Syriopoulou, D., Ramanujam, G.
3D-MADPD is a suite of PC and mainframe models for simulating 2-0, 2 1/2D (quasi-3D) and 3D solute
transport in a steady flow field. The Principal Directions (PD) of the transport form of the mass balance
equation is discretized by finite difference approximations along the curvilinear PD coordinates. The
integration in each direction is carried out by a Locally One Dimensional (LOD) scheme during each step
of the fractional time stepping. Longitudinal transport is computed by the Matched Artificial Dispersivity
(MAD) method, limiting the integration to the area of actual plume extent. Grid design requires simultaneous
selection of Courant and grid Peclet numbers to meet accuracy constraints. The model has been compared
with the chloride plume observed at the Borden landfill, Ottawa, Canada.
Contact Address: A.D. Koussis, Dept. of Civil and Env. Eng., Vanderbilt Univ., Nashville, TN 37235
IGWMC Key: 5800 Model Name: MODMOC-3D Released: 1992
Authors: Williams, P.M.
MODMOC-3D adds a three-dimensional reactive, advective-dispersive solute transport module to the USGS
finite difference flow model MODFLOW. The solute transport module is based on the method of
characteristics and is compatible with a slightly modified version of the 3D multi-layered version of
MODFLOW. MODMOC-3D can be run in 2D or 3D as a flow model, a flow and solute transport model, or
as a solute transport model only. When run as a solute transport model, MODMOC-3D uses the starting
water levels and aquifer parameter data from the flow model input file to calculate velocities. The model
handles decay, linear, Freundlich or Langmuir sorption, monovalent or divalent exchange. It supports solute
transport subgrids. Output includes velocities, dispersion coefficients, and concentration distribution.
Contact Address: P.M. Williams, Aquifer Simulation Inc., 102 Chester Road, Fremont. NH 03044
C.3-1-7
-------
Appendix C.3, part 1 (continued)
IGWMC Key: 5822 Model Name: SAFTAP Released: 1991
Authors: Huyakorn, P.S., Blandford, T.N.
SAFTAP (SAturated Flow and Transport And Particle tracking) simulates saturated groundwater flow and
solute transport in 3D. It is composed of two separate modules: the flow and transport module FTM, and
the particle tracking module PTM. FTM is a finite element code for multi-aquifer systems with a wide range
of aquifer conditions (e.g., confined, unconfined or partially confined with storage conversion). It analyses
3D unconfined flow using a saturated-pseudo unsaturated modeling approach, allowing the prediction of
the water table and flow rates without characterization of the unsaturated zone. Many types of steady-state
or time-dependent boundary conditions can be used. Transport mechanisms considered include advection,
dispersion, molecular diffusion, adsorption, and first-order degradation.
FTM includes various matrix solvers: direct banded, layer successive over-relaxation,
preconditioned-conjugate gradient, and ORTHOMIN accelerated conjugate gradient solver. The most
efficient solver is automatically selected dependent on the dimensionality of the problem. The transport
equation is approximated using the upstream-weighted residual finite element method. Various types of
time-varying sources and observation points may be introduced.
PTM performs 1-D solute transport analysis along a pathline defined through input of head distribution and
interpolation of velocities. It uses the 1D upstream-weighted finite element method and include advection,
longitudinal dispersion, retardation and first-order degradation. PTM's output can be used by various
post-processing software, such as the GRAF module of the WHPA code for pathline generation..
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 900, Herndon, VA 22070
C.3-1-8
-------
Appendix C.3: Solute Transport; Three-Dimensional Numerical Models for Saturated Zone, Part 2:
Usability and Reliability
IGWMC
Key
515
582
692
697
2070
2691
3840
3841
3842
4610
4631
4700
4933
4941
4970
5161
5520
5650
5800
5822
Model
PTC
GREASE
SWIP/SWIPR/
DWDM
SWENT
CFEST
RAND3D
SWIFT
SWIFT II
SWIFT III/
SWIFT-386
HST3D
SWICHA
DSTRAM
TARGET-3DS
DYNTRACK
MT3D
INTERTRANS
FTWORK
3D-MADPD
MODMOC-3D
SAFTAP
Usability
Preprocessor
Y
U
N
N
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
U
Y
Y
Postprocessor
U
U
N
N
Y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
N
U
Y
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
Y
N
N
N
Y
Y
N
N
Y
N
Y
Y
Y
Y
Y
Y
N
U
Y
Y
c
o
a
a.
<0
L
L
N
N
Y
L
N
N
L
L
Y
Y
Y
Y
Y
Y
L
U
Y
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
U
Y
Peer Reviewed Coding
U
U
U
U
U
U
Y
Y
U
U
U
U
U
U
U
U
N
U
U
U
•o
•
*C
0
L
L
L
L
E
L
E
E
E
L
L
L
L
L
L
U
L
L
L
L
•Q
s
5
•o
1
L
L
L
L
E
U
E
E
E
U
U
U
U
U
L
U
L
U
U
L
£
3
~s
•o
o
M
F
M
F
M
F
M
M
M
M
F
U
U
M
M
U
F
U
U
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.3-2-1
-------
Appendix C.4: Solute Transport; Models for Unsaturated Zone, Part 1: Model Description
IGWMC Key: 583 Model Name: SATURN Released: 1985
Authors: Huyakorn, P.S., S.D. Thomas, J.W. Mercer, and B.H. Lester
SATURN (SATurated-Unsaturated flow and RadioNuclide transport) is a two-dimensional finite element model
to simulate transient, single phase fluid flow and advective-dispersive transport of radionuclides and other
contaminants in fully or partially saturated, anisotropic, heterogeneous porous media. The flow problem is
solved using the Galerkin method to approximate the governing equation, and either the Picard or
Newton-Raphson iterative techniques to treat material nonlinearities. It uses the upstream-weighted residual
method to treat the transport equation.
Contact Address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 2891 Model Name: GS2 Released: 1985
Authors: Davis, LA., and G. Segol
GS2 is a two-dimensional Galerkin finite element code for the analysis of flow and contaminant transport in
partially saturated media. Either vertical or horizontal plane simulation is possible. Mass transport analysis
includes convection, dispersion, radioactive decay and adsorption.
Contact Address: LA. Davis, Water, Waste and Land, Inc., 1311 S. College Avenue, Fort Collins, CO
80524
IGWMC Key: 2892 Model Name: GS3 Released: 1985
Authors: Davis, L.A., and G. Segol
GS3 is a three-dimensional Galerkin finite element code for analysis of fluid flow and contaminant transport
in partially saturated media. The code is particularly useful for simulation of anisotropic systems with strata
of varying thickness and continuity. This code contains many of the same features as UNSAT2 (IGWMC Key
# 0021) such as the ability to simulate mixed Dirichlet and Neuman boundary conditions for flow and mass
transport (concentration of waste leaving the system through evaporated water is zero) by specifying
minimum surface pressure and maximum infiltration rate, and seepage faces. However, it will not simulate
evapotranspiration by defining a root zone and corresponding plant species data. Unsaturated hydraulic
properties are input in table form. There is no restart feature.
Contact Address: LA. Davis, Water, Waste and Land, Inc., 1311 S. College Avenue, Fort Collins, CO
80524
IGWMC Key: 3234 Model Name: VADOSE Released: 1982
Author: Sagar, B.
VADOSE is an integrated finite difference model for analysis of steady or transient, two-dimensional areal,
cross-sectional or radial simulation of coupled density-dependent transport of moisture, heat and solutes
in variably-saturated, heterogeneous, anisotropic porous media.
Contact Address: B. Sagar, Southwest Research Inst., Div. 20,6220 Culebra Road, P.O. Drawer 0510,
San Antonio, TX 38510
C.4-1-1
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 3235 Model Name: FLOTRA Released: 1982
Author: Sagar, B.
FLOTRA is an integrated finite difference model for simulation of steady or transient, two-dimensional areal,
cross-sectional or radial, density- dependent flow, heat and mass transport in variably saturated, anisotropic,
heterogeneous, deformable porous media.
Contact Address: B. Sagar, Southwest Research Inst., Div. 20,6220 Culebra Road, P.O. Drawer 0510,
San Antonio, TX 38510
IGWMC Key: 3238 Model Name: PORFLOW-3D Released: 1992
Author: Runchal, A.K.
PORFLOW-3D is an integrated finite difference model to simulate coupled transient or steady-state,
multiphase, fluid flow, and heat, salinity, or chemical species transport in variably saturated porous or
fractured, anisotropic and heterogeneous media. The program facilitates arbitrary sources or sinks in
three-dimensional cartesian or axisymmetric (cylindrical) geometry. The user interface is based on the
FREEFORM language using simple English-like commands. The software includes the ARCPLOT graphic
post processor.
Contact Address: A. Runchal, 1931 Stradella Road, Bel Air, CA 90077
IGWMC Key: 3371 Model Name: FEMWASTE/FECWASTE Released: 1987
Authors: Yeh, G.T., and D.S. Ward
FEMWASTE/FECWASTE are two-dimensional finite element models for transient simulation of areal or
cross-sectional transport of dissolved non-conservative constituents for a given velocity field in an
anisotropic, heterogeneous saturated or unsaturated porous medium. The velocity field is generated by
the accompanying FEMWATER/FECWATER two-dimensional flow models.
Contact Address: G.T. Yeh, Penn State Univ., Dept. of Civil Eng., 225 Sackett Bldg, University Park,
PA 16802
IGWMC Key: 3411 Model Name: LEACHMP Released: 1992
Authors: Wagenet, R.J., and J.L Hutson
LEACHMP Leaching Estimation And Chemistry Model - Pesticides) simulates transport and fate of
non-volatile pesticides in the unsaturated zone. Finite difference techniques are used to calculate water and
solute movement. It models a multilayered soil profile under transient conditions and can incorporate linear
equilibrium adsorption and degradation of pesticides and plant uptake of water and pesticides. The model
can address multiple rainfall and evaporation cycles including ponding conditions. Pesticides can be applied
in wet or dry form to the soil surface. The program allows for oxidation and hydrolysis reactions of
pesticides, such as Aldicarb.
Contact Address: R.J. Wagenet, Dept. of Soil, Crop and Atmospheric Sc., Cornell Univ., Ithica, New
York 14853
C.4-1-2
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 3432 Model Name: QCTFIT Released: 1985
Authors: Parker, J.C., M.Th. Van Genuchten
The purpose of CXTFIT is to determine values for one-dimensional analytical solute transport parameters
using a nonlinear least-squares inversion method. The analytical model includes advection, dispersion,
diffusion, first-order decay and zero-order production.
Contact Address: J.C. Parker, Virginia Polytechnical Institute, Dept. Soil & Environmental Science,
Blacksburg, VA 24061; or Internal. Ground Water Modeling Ctr., Colorado Sch. of
Mines, Golden, CO 80401.
IGWMC Key: 3450/3451 Model Name: DISPEQ/DISPER/PISTON Released: 1983
Authors: Fluhler, H., and W.A. Jury
DISPEQ/DISPER/PISTON is a series of three finite difference research models to simulate one-dimensional
transport of reactive solute species through soil columns, including dispersion, instantaneous equilibrium
adsorption (DISPEQ) and rate dependent adsorption (DISPER). PISTON is based on piston type flow
without dispersion.
Contact Address: H.U. Fluhler, 240 Nick Davis Road, Madison, AL 35758
IGWMC Key: 3540 Model Name: CREAMS Released: 1982
Author: Knisel, W.G.
CREAMS (A field scale model for Chemicals, Runoff, and Erosion from Agricultural Management Systems)
is a general watershed model designed to evaluate non-point source pollution from alternate management
practices for field-size areas. It consists of three main components: hydrology, erosion/sedimentation and
chemistry. The hydrology model handles storm runoff, infiltration, soil water movement (providing amount
of seepage beneath root zone and initial soil water content before a storm), and soil/plant evapotranspiration
between storms. The chemistry model includes a nutrient (nitrogen and phosphorus) submodel and a
pesticide submodel. CREAMS was developed for evaluation of agricultural management systems and their
effects on non-point pollution potential. CREAMS is the predecessor of GLEAMS.
Contact Address: W.G. Knisel, USDA Agricultural Research Service, Southeast Watershed Research
Laboratory, P.O. Box 946, Tifton, GA 31793
IGWMC Key: 3541 Model Name: GLEAMS Released: 1990
Authors: Leonard, R.A., W.G. Knisel, and F.M. Davis
GLEAMS (Groundwater Loading Effects on Agricultural Management Systems) was developed as an
extension of an earlier USDA model, CREAMS. Both models simulate soil water balance and surface
transport of sediments and chemicals from agricultural field management units. GLEAMS, in addition,
simulates chemical transport in and through the plant root zone. Several other features were added such
as irrigation/chemigation options, pesticide metabolite tracking, and software to facilitate model
implementation and output data analysis. Input requirements for the model include daily rainfall volumes,
crop and management parameters; soil and physical parameters; pesticide property data such as solubility,
and expected half-life in soil and/or foliage.
Contact Address: USDA-ARS, P.O. Box 946, Tifton, GA 31793
C.4-1-3
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 3830 Model Name: SUTRA Released: 1990
Author: Voss, C.I.
SUTRA (Saturated-Unsaturated TRAnsport) simulates transient or steady-state, two-dimensional, variably
saturated, fluid density dependent ground water flow with transport of energy or chemically reactive species
solute transport. The model employs a hybrid finite-element and integrated-finite-difference method to
approximate the coupled equations. Solute transport include advection, dispersion, diffusion, equilibrium
adsorption on the porous matrix, and both first-order and zero-order decay or production. Energy transport
may take place in both the solid matrix and the liquid phase. SUTRA may be employed in both areal
(horizontal) and cross-sectional mode for saturated systems or in cross-sectional mode only for unsaturated
systems.
SUTRA provides, as preliminary calculated results, fluid pressures and either solute concentrations or
temperatures. Mesh construction is flexible for arbitrary geometries employing quadrilateral finite elements
in Cartesian or radial-cylindrical coordinates. The mesh might be coarsened through the use of pinch
nodes. Boundary conditions, sources and sinks may be time dependent. The model has a rest art option.
Options are also available to print fluid velocities, and fluid mass, and solute mass or energy budgets for
the system. SUTRA's numerical algorithms are not specifically applicable to non-linearities of unsaturated
flow. Therefor SUTRA, as distributed by the USGS, requires fine spatial and temporal discretization for
unsaturated flow. The user can replace the included function for unsaturated flow by others, and recompile
the code.
Contact Address: Voss, C.I., U.S. Geological Survey, 431 National Center, Reston, VA 22092;
Internal. Ground Water Modeling Ctr., Colorado Sen. of Mines, Golden, CO 80401;
or Scientific Software, Washington, D.C.
IGWMC Key: 4081 Model Name: TRIPM Released: 1983
Author: Gureghian, A.B.
TRIPM is a two-dimensional finite element model to predict the transport of radionuclides decay chain into
and in a phreatic aquifer. It simulates the simultaneous cross-sectional flow water and the transport of
reacting solutes through saturated and unsaturated porous media. The influence of soil-water pH on the
distribution coefficient is included. Boundary conditions include seepage faces.
Contact Address: Performance Assessment Dept., Office of Nuclear Waste Isolation, Battelle Project
Management Division, 505 King Avenue, Columbus, OH 43201
IGWMC Key: 4140 Model Name: MLSOIL/DFSOIL Released: 1984
Authors: Sjoreen, A.L., D.C. Kocher, G.G. Killough, and C.W. Miller.
MLSOIL (Multi-Layer SOIL model) calculates an effective ground surface concentration to be used in
computations of external doses. The program implements a five compartment linear-transfer model to
calculate the concentrations of radionuclides in the soil following deposition on the ground surface from the
atmosphere. The model considers leaching through the soil as well as radioactive decay and buildup.
DFSOIL calculates the dose in air per unit concentration at 1m above the ground from each of the five soil
layers used in MLSOIL and the dose per unit concentration from an infinite plane source. MLSOIL and
DFSOIL are part of the Computerized Radiological Risk Investigation System (CRRIS).
Contact Address: A.L Sjoreen, Oak Ridge Nat. Lab., Health and Safety Research Div., Oak Ridge,
Tennessee 37831
C.4-1-4
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Appendix C.4, part 1 (continued)
IGWMC Key: 4270 Model Name: TRACR3D Released: 1984
Author: Travis, B.J.
TRACR3D is a three-dimensional finite difference model for simulation of transient two-phase flow of water
and air and transport of non-conservative multi-component transport in deformable, heterogeneous,
water-saturated or variably-saturated, reactive porous and/or fractured media.
Contact Address: Travis, B.J., Los Alamos National Laboratory, MS-F665, Los Alamos, NM 87545
IGWMC Key: 4290 Model Name: CADIL/AGTEHM Released: 1984
Authors: Emerson, C.J., B. Thomas, R.J. Luxmoore, and D.M. Hetrick
CADIL (Chemical Adsorption and Degradation In Land) is a moisture and chemical species mass balance
model which simulates chemical transport through soils. It includes the processes of deposition, infiltration,
adsorption (Freundlich isotherm) and first-order (bio-)chemical degradation of chemicals. It also simulates
the effect of soil temperature on chemical degradation. Chemical transport in soil water may be either
vertical or lateral. Both macropore and matrix flows of chemicals in soil water are modeled. CADIL couples
to AGTEHM, which in turn calculates soil water transport through the bulk matrix and soil macro-pores.
AGTEHM simulates interception, throughfall, infiltration, soil evaporation, plant transpiration, and surface
runoff.
Contact Address: Emerson, C.J., Oak Ridge National Laboratory, Computer Sciences Department,
Oak Ridge, TN 37831
IGWMC Key: 4350 Model Name: FEMTRAN Released: 1984
Author: Martinez, M.J.
FEMTRAN is a two-dimensional finite element model to simulate cross-sectional advective radionuclide
transport in saturated/unsaturated porous media. The model considers chain-decay of the radionuclides.
It requires user prescribed heads.
Contact Address: M. Martinez, Sandia National Laboratories, Fluid Mechanics and Heat Transfer Div.,
Albuquerque, NM 87185
IGWMC Key: 4391 Model Name: SBIR Released: 1987
Author: Li, R-M.
SBIR is a three-dimensional finite difference model for simulation of flow and mass transport in a variable
saturated porous medium. A vector processor is used in the solution. Benchmark tests indicated the
relatively high efficiency of the code.
Contact Address: Li, Ruh-Ming, 3901 Westerly Place, Suite 101, Newport Beach, CA 92660
IGWMC Key: 4570 Model Name: VS2D/VS2DT Released: 1990
Authors: Lappala, E.G., R.W. Healy, and E.P. Weeks
VS2D is a two-dimensional finite difference simulator for cross-sectional or cylindrical variably saturated flow
in porous media. The model allows consideration of non-linear storage, conductance, and sink terms and
boundary conditions. Processes included are infiltration, evaporation and plant root uptake. The program
also handles seepage faces. VS2DT is a solute transport module to be used with VS2D. It is based on a
(continued )
C.4-1-5
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Appendix C.4, part 1 (continued)
VS2D/VS2DT - continued
finite difference approximation of the advection-dispersion equation for a single species. Program options
include first-order decay, equilibrium adsorption described by Freundlich or Langmuir isotherms, and
ion-exchange. Nonlinear storage terms are linearized by an implicit Newton-Raphson method.
Nonlinear conductance terms, boundary conditions, and sink terms are linearized implicitly. Relative
hydraulic conductivity is evaluated at cell boundaries by using full upstream weighting, the arithmetic mean,
or the geometric mean of values of adjacent cells. Saturated hydraulic conductivities are evaluated at cell
boundaries by using distance weighted harmonic means. The linearized matrix equations are solved using
the strongly implicit method. Nonlinear conductance and storage coefficients are represented by closed-form
algebraic equations or interpolated from tables.
Nonlinear boundary conditions treated by the code include infiltration, evaporation, and seepage faces.
Extraction by plant roots is included as a nonlinear sink term. Initial conditions may be input as moisture
content or pressure head by blocks defined by row and column, or in a formatted file by cell. An equilibrium
profile may be specified above a user defined free water surface. Infiltration may be simulated by specified
flux nodes, specified pressure nodes, or a ponding function where the user specifies rainfall rate and
ponding height. Evaporation is simulated by a user defined potential evapotranspiration, pressure potential
of the atmosphere, and surface resistance. Evapotranspiration is simulated through the use of user defined
potential evapotranspiration, minimum root pressure, depth of rooting, and root activity at the bottom of the
root zone and land surface. Seepage faces may also be simulated.
Contact Address: Weeks, E.P., U.S. Geological Survey, Box 25046, M.S. 413, Denver Federal Center,
Denver, CO 80225; or Internat. Ground Water Modeling Ctr., Colorado Sch. of
Mines, Golden, CO 80401.
IGWMC Key: 4630 Model Name: FLAMINGO Released: 1985
Author: Huyakorn, P.S.
FLAMINGO is a three-dimensional upstream weighted finite element model to simulate transient water flow
and solute transport processes in fully- and variably saturated porous media. Transport processes included
are advection, hydrodynamic dispersion, linear equilibrium adsorption and first-order decay. Nonlinearities
due to unsaturated soil properties and atmospheric boundary conditions are treated using Picard iterations.
The model uses a Slice Successive Over Relaxation (SSOR) matrix solution scheme.
Contact Address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 4690 Model Name: VAM2D Released: 1988
Author: Huyakorn, P.S.
VAM2D (Variably saturated Analysis Model in 2 Dimensions) is a two-dimensional Galerkin finite element
model to simulate flow and contaminant transport in variably saturated porous media. The code can perform
simulations in an areal plane, a cross-section, or an axisymmetric configuration. The highly nonlinear soil
moisture relations can be treated using Picard or Newton-Raphson iterations. The model uses the upstream
weighted residual method to treat the advective-dispersive transport equation with linear or non-linear
equilibrium sorption, and first-order degradation. Cross-sectional unconfined flow problems can be analyzed
using a rigorous unsaturated-saturated modeling approach or an approximate saturated-pseudo unsaturated
modeling approach that does not require user-supplied soil moisture relations.
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 100, Herndon, VA 22070
C.4-1-6
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Appendix C.4, part 1 (continued)
IGWMC Key: 4691 Model Name: VAM3D Released: 1988
Author: Huyakorn, P.S.
VAM3D (Variably saturated Analysis Model in 3 Dimensions) is a three-dimensional finite-element model for
simulation of flow and contaminant transport in variably saturated porous media. It is capable of
steady-state and transient simulations in an area! plane, a cross-section, an axisymmetric configuration, or
a fully three-dimensional mode using rectangular and triangular prisms. Nonlinearities in the unsaturated
flow equation is solved using Picard iteration. The matrix equations are solved using a slice-successive
over-relaxation scheme or conjugate gradient algorithms. The advective-dispersive transport equation is
solved using upstream weighted procedure. Transport includes linear and Freundlich adsorption isotherms
and first-order degradation. An element mesh generator is available.
Contact Address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 100, Herndon, VA 22070
IGWMC Key: 4693 Model Name: VADOFT Released: 1988
Authors: Huyakorn, P.S., T.D. Wadsworth, H.O. White Jr., and J.E. Buckley
VADOFT is a one-dimensional finite element code that solves the Richard's equation for flows in the
unsaturated zone. The user may make use of constitutive relationships between pressure, water content,
and hydraulic conductivity to solve the flow equations. VADOFT also simulates the fate and transport of two
parent and two daughter products.
Contact Address: Hydrogeologic, Inc., 1165 Herndon Parkway, #900, Herndon, VA 22070
IGWMC Key: 4720 Model Name: PRZM Released: 1984
Authors: Carsel, R.F., C.N. Smith, LA. Mulkey, and J.D. Dean
PRZM (Pesticide Root Zone Model) simulates the vertical one-dimensional movement of pesticides in the
unsaturated zone within and below the root zone. The model consists of hydrologic (flow) and chemical
transport components to simulate runoff, erosion, plant uptake, leaching, decay, foliar washoff, and
volatilization. Pesticide transport and fate processes include advection, dispersion, molecular diffusion, and
soil sorption. The model includes soil temperature effects, volatilization and vapor phase transport in soils,
irrigation simulation and a method of characteristics algorithm to eliminate numerical dispersion. PRZM is
capable of simulating fate and transport of the parent and up to two daughter species. Predictions can be
made for daily, monthly or annual output. A finite difference numerical solution, using a backwards
difference implicit scheme, is employed. PRZM allows the user to perform dynamic simulations considering
pulse loads, predicting peak events, and estimating time-varying emission or concentration profiles in layered
soils. PRZM, VADOFT and SAFTMOD are part of RUSTIC. RUSTIC (MARS Key # 4721) links these models
in order to predict the fate and transport of chemicals to drinking water wells. The codes are linked together
with the aid of a flexible execution supervisor (software user interface) that allows the user to build models
that fit site-specific situations.
Contact Address: R.F. Carsel, U.S. Environm. Prot. Agency, Environm. Res. Lab., Athens, GA 30613
C.4-1-7
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Appendix C.4, part 1 (continued)
IGWMC Key: 4721 Model Name: RUSTIC Released: 1989
Authors: Dean, J.D., P.S. Huyakorn, A.S. Donigan, Jr., K.A. Voos, R.W. Schanz, Y.J. Meeks, and R.F. Carsel
RUSTIC is a coupled root zone (PRZM), unsaturated zone (VADOFT), and saturated zone (SAFTMOD)
modeling package. RUSTIC links these models in order to predict the fate and transport of chemicals to
drinking water wells. The codes are linked together with the aid of a flexible execution supervisor (software
interface) that allows the user to build models that fit site-specific situations. For exposure assessments,
the code is equipped with a Monte Carlo pre- and post-processor.
Contact Address: R.F. Carsel, U.S. EPA, Environm. Res. Lab., Athens, GA 30613
IGWMC Key: 4931 Model Name: TARGET-2DU Released: 1985
Authors: Moreno, J.L, M.I. Asgian, S.D. Lympany, and P-J. Pralong.
TARGET-2DU is one of five models of the TARGET series (Transient Analyzer of Reacting Groundwater and
Effluent Transport). It simulates two-dimensional, variably saturated, density coupled, transient groundwater
flow and solute transport using a hybrid finite difference method. The transport is based on the solution
of the advective-dispersive transport equation for a single non-conservative contaminant with linear
equilibrium adsorption (retardation). The solution method used is based on an iterative alternating direction
implicit method.
Contact Address: Dames & Moore, 1125 17th Str, #1200, Denver, Colorado 80202
IGWMC Key: 4934 Model Name: TARGET-SDU Released: 1985
Authors: Moreno, J.L, M.I. Asgian, S.D. Lympany, and P-J. Pralong
TARGET-SDU is one of five models of the TARGET series (Transient Analyzer of Reacting Groundwater and
Effluent Transport). It simulates three-dimensional, variably-saturated, density-coupled, transient groundwater
flow and solute transport using a hybrid finite difference method. The transport is based on the solution
of the advective-dispersive transport equation for a single non-conservative contaminant with linear
equilibrium adsorption (retardation). The solution method used is based on an iterative alternating direction
implicit method.
Contact Address: Dames & Moore, 1125 17th. Str., #1200, Denver, Colorado 80202
IGWMC Key: 5021 Model Name: BIOSOIL Released: 1986
Author: Baek, N.H.
The system modeled by BIOSOIL consists of four components: 1) soil water flow to transport a limiting
substrate and a recalcitrant chemical; 2) chemical persistence mitigated by an ultimate removal mechanism
of biodegradation; 3) soil microbial growth enriched by exogenous supply of a limiting substrate; and 4)
substrate availability to support soil microbial growth for the enhancement of chemical removal.
Variable-step and variable order Gear's method is employed as a numerical approximation to solve the set
of four ODE's which result from the transformation of four PDE's via the finite difference method. The
response of the system to different values for such model inputs as substrate concentration, application rate,
and application cycle can be studied.
Contact Address: N.H. Baek, Occidental Chemical Corporation, Technology Center, 2801 Long Road,
Grand Island, NY 14072
C.4-1-8
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Appendix C.4, part 1 (continued)
IGWMC Key: 5028 Model Name: GTC (Group Transfer Concentration) Released: 1985
Authors: Yu, C., W.A. Jester, and A.R. Jarrett
GTC is a general purpose finite difference solute transport model developed to simulate solute movement
in both homogeneous and non-homogeneous media. It splits up the modeled area in zones of constant
properties, including dispersion coefficient, retardation factor, and degradation rate. Mass transfer between
the solid phase and the liquid phase is proportional to the concentration gradient. The GTC model can be
used for both saturated and unsaturated conditions. It covers the conventional advection-dispersion model,
the mobile-immobile pore model, the nonequilibrium adsorption-desorption model and the jointed porous
rock model.
Contact Address: C. Yu, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439
IGWMC Key: 5031 Model Name: CTSPAC Released: 1988
Authors: Lindstrom, FT., D.E. Cawlfield, and L Boersma
CTSPAC is an one-dimensional numerical model that couples the flow of water and the transport of heat and
solutes in layered soils with the uptake and transport of water and solutes in plants. Initial root distribution
is specified. The rate of uptake is a function of the environmental conditions that determine the plant's
transpiration rate. Water transport in the plant is based on water potential and pressure gradients according
to Munch pressure flow hypothesis. The model was developed for assessing risks involved in the use of
xenobiotic chemicals. It allows an evaluation of the rate of uptake of such chemicals from the soil solution
and the accumulation in the various plant parts.
Contact Address: L. Boersma, Dept. of Soil Science, Oregon State University, Corvallis, OR 97331
IGWMC Key: 5039 Model Name: SESOIL (Seasonal Soil Compartment Modefleleased: 1987
Author: Bonazountas, M.
SESOIL is a user-friendly finite-difference soil compartment model designed for long-term hydrologic,
sediment, and pollutant fate simulations. The model distinguishes three major components, the hydrological
cycle, the sediment cycle and pollutant transport and fate. Elements of the hydrologic cycle included are
rainfall, soil moisture variations, infiltration, exfiltration, surface runoff, evapotranspiration, and groundwater
runoff; simulation of the sediment cycle include sediment washload from storms and sediment resuspension
due to wind; the pollutant fate cycle simulated takes into account advection, diffusion, volatilization,
adsorption and desorption, chemical degradation or decay, biological transformations, hydrolysis,
complexation, and ion exchange.
Contact Address: D. Hetrick, 8417 Mecklenburg Court, Knoxville, TN 37923
IGWMC Key: 5186 Model Name: NITRO Released: --
Authors: Kaluarachchi, J.J., and J.C. Parker
NITRO is a 2-dimensional vertical section or radially symmetric finite element program for simulation of
steady-state and transient uncoupled flow and transport in the unsaturated zone. The nonlinearity is handled
by Picard iteration. Soil hydraulic properties are described by the Brooks-Corey or van Genuchten model
with hysteresis. The model handles transport of up to two species with linear or Freundlich equilibrium
adsorption and zero and first order transformations. It facilitates atmospheric and seepage boundaries as
well as first-type and second-type (flux) boundary conditions.
Contact Address: J.C. Parker, Environmental Systems & Technologies, Inc., P.O. Box 10457,
Blacksburg, VA 24062-0457
C.4-1-9
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Appendix C.4, part 1 (continued)
IGWMC Key: 5213 Model Name: TDFD10 Released: --
Author: Slotta, LS.
TDFD1O (Two-Dimensional Finite Difference 1st Order sorption) is a two-dimensional model for simultaneous
simulation of movement of moisture, transport of heat, and transport and fate of a contaminant in a shallow
unconfined aquifer. The porous medium may be heterogeneous. The coupled system of non-linear
unsaturated/saturated moisture flow and heat and chemical transport are solved using a finite difference
approximation. The porous medium is partitioned in three fractions: sand, clay, and organic material, with
for each fraction first-order sorption kinetics included. Time integration is performed using the backward
Euler method. Dynamic boundary conditions at the air-porous medium interface are included. A variety of
first- and second-type boundary conditions are included.
Contact Address: J. Heydarpour, Slotta Engineering Assoc., Inc., P.O. Box 1376, Corvallis, OR 97339
IGWMC Key: 5220 Model Name: VSAFT2 Released: 1990
Authors: Yeh, T.C.J.
VSAFT2 (Variably SAturated Flow and Transport in 2 dimensions) is a program for simulating
two-dimensional steady or transient, variably saturated flow and convective-dispersive transport of a
conservative solute, using a finite element method with the Newton-Raphson or Picard iteration scheme.
For the linear equation solution a preconditioned conjugate gradient method is used. Solute transport is
handled by an upstream weighting scheme. The model uses rectangular and/or triangular finite elements
and a banded matrix solver. The two-dimensional flow can be either in a horizontal or in a vertical plane.
Furthermore, the model can handle radial symmetric simulations. The code contains a restart feature for
changing boundary conditions.
Evapotranspiration is simulated in VSAFT2 by a user specified root zone consisting of one or more plant
species. User supplied information on the root zone includes wilting pressure, maximum transpiration rate,
root effectiveness function, and root zone geometric data. Evaporation \ Infiltration is simulated through
user defined maximum evaporation or infiltration rates, minimum soil surface pressure head, and soil surface
geometric data. Analytical functions must be used for relative hydraulic conductivity relationships and
moisture characteristic curve functions. The user is given the choice of the van Genuchten model,
exponential model, Gardener-Russo model, or a user specified function for which a subroutine must be
written.
Contact Address: T.C.J. Yeh, Dept. of Hydrology and Water Resources, Univ. of Arizona, Tuscon, AZ
85721
IGWMC Key: 5310 Model Name: PRZMAL Released: 1986
Authors: Wagner, J., and C. Ruiz-Calzada
PRZMAL is an aquifer linkage model for US EPA's Pesticide Root Zone Model (PRZM). It connects PRZM
with the analytical three-dimensional transport model PLUME 3D developed at Oklahoma State University.
This linkage allows the user to predict contaminant movement from the point of application, in a continuous
manner, into and within the aquifer.
Contact Address: J. Wagner, Oklahoma State Univ., School of Chem. Eng., Stillwater, OK 74074
C.4-1-10
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Appendix C.4, part 1 (continued)
IGWMC Key: 5500 Model Name: BIO1D Released: 1989
Authors: Srinivasan, P., and J.W. Mercer
BIO1D is a one-dimensional finite difference model for simulation of biodegradation and sorption in reactive
contaminant transport in a uniform flow field. Advective and dispersive transport of a substrate and an
electron acceptor are considered. The reactions may include aerobic (Monod function) and anaerobic
(Michaelis- Menten kinetics) degradation, and/or adsorption described by a linear, Freundlich or Langmuir
equilibrium isotherm. Dirichlet, Neumann, or Cauchy boundary conditions are allowed. The resulting
nonlinear problem is solved using a Newton-Raphson itrtive technique. The program includes an
user-friendly preprocessor and post simulation display graphics. The program assumes flow velocities
known.
Contact Address: GeoTrans, Inc.. 46050 Manekin Plaza. Suite 100, Sterling, VA 22170
IGWMC Key: 5630 Model Name: MULTIMED Released: --
Authors: ~
MULTIMED is a multimedia transport model that simulates the movement of contaminants leaching from a
waste disposal facility. The model includes two options or simulating leachate flux. Either the infiltration rate
to the unsaturated or saturated zone can be specified directly or a landfill module can be used to estimate
the infiltration rate. The landfill module is one-dimensional and steady-state, and simulates the effect of
precipitation, runoff, infiltration, evapotranspiration, barrier layers (which can include flexible membrane
liners), and lateral drainage. A steady-state, one-dimensional, semi-analytical module simulates flow in the
unsaturated zone. The output from this module, water saturation as function of depth, is used as input to
the unsaturated transport module.
The unsaturated transport module simulates transient, one-dimensional (vertical) transport and includes the
effects of longitudinal dispersion, linear adsorption, and first-order decay. Output from this module -i.e.
steady-state or time-varying concentrations at the water table- is used to couple the unsaturated zone
transport module with a steady-state or transient, semi-analytical saturated zone transport module. The
saturated zone transport model of MULTIMED includes one-dimensional uniform flow, three-dimensional
dispersion, linear adsorption (retardation), first-order decay, and dilution due to direct infiltration into the
ground water plume. Contamination of a surface stream due to the complete interception of a steady-state
saturated zone plume is simulated by the surface water module. Finally, the air emissions and the
atmosphere dispersion modules simulate the movement of chemicals into the atmosphere. The module
includes option for Monte Carlo simulations.
Contact Address: U.S. EPA, Environm. Res. Lab., Athens, GA 30613
IGWMC Key: 5661 Model Name: FLAME Released: 1992
Authors: Baca, R.G., and S.O. Magnuson
FLAME is a finite element code designed to simulate two-dimensional, cross-sectional subsurface transport
of low-concentration contaminants in either time-dependent or steady-state, known flow field in a highly
heterogeneous variably-saturated porous media with complex stratigraphy. The code can be applied to
two-dimensional transport in an arid vadose zone or in an unconfined aquifer. FLAME handles
advective-dispersive transport, equilibrium sorption using a linear isotherm, first-order decay, and a complex
source/sink term. It accommodates advection-dominated mass transport. In addition, the code has the
capability to describe transport processes in a porous media with discrete fractures. It describes the mass
transfer between the porous media and discrete fractures.
(continued )
C.4-1-11
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Appendix C.4, part 1 (continued)
FLAME - continued
FLAME can handle both Dirichlet and Neumann transport boundary conditions. The code can model
transport of contaminants in a single phase, being either liquid, gaseous (e.g. organic vapors), or colloidal.
The modified equation approach of Fletcher with a build-in dissipation mechanism is used to dampen
oscillations in a convection dominated transport system. The resulting finite element matrix equations are
solved by a Gaussian elimination procedure without pivoting. Two solvers are used: 1) standard band solver
utilizing a skyline storage scheme, and 2) frontal method.
Contact Address: Baca, R.G., Idaho Nat. Eng. Lab., EG&G Idaho, Inc., P.O. Box 1625, Idaho Falls,
Idaho 83415
IGWMC Key: 5681 Model Name: VIP Released: 1991
Authors: Stevens, O.K., W.J. Grenney, and Z. Van
VIP (Vadose zone Interactive Processes model) is an one-dimensional finite-difference solute transport and
fate model for simulating the behavior of organic (oily) compounds in the vadose zone as part of a land
treatment system. The model uses advection and dispersion in the water and air phases as the dominant
transport mechanism for contaminant and oxygen. Monthly values for recharge rate and soil moisture
conditions are used to calculate an effective water velocity. The model includes first-order degradation of
a contaminant in water, air and soil, and of oxygen. It uses an implicit technique to calculate the
degradation of the contaminant in the oil phase as well as the oil phase itself, and related oxygen changes.
VIP uses partition coefficients and rate constants to calculate contaminant concentration in each medium.
The model has various output options including echo of input data, (graphic) profile of initial condition
(constituent concentration in water, oil, air, and soil phases), and the initial fractions as well as initial oxygen
concentration. Other output options include (graphic) depth-concentration profiles and data versus time
tables. Input preparation facilitates exchange of Lotus 123 and wordprocessed ASCII files.
Contact Address: O.K. Stevens, Civil and Environm. Eng. Dept., Utah State Univ., UMC 4110, Logan,
Utah 84321; or Center for Subsurface Modeling Support (CSMOS), R.S. Kerr
Environm. Res. Lab.. U.S. EPA, P.O. Box 1198, Ada. OK 74820
IGWMC Key: 5690 Model Name: VLEACH Released: 1990
Author: J. Turin
VLEACH (Vadose Zone LEACHing Model) is a relatively simple one-dimensional finite difference model
designed to simulate leaching of a volatile, adsorbed contaminant through the vadose zone. It can be used
to simulate the transport of any non-reactive chemical that displays linear partitioning behavior. In particular,
VLEACH simulates downward liquid-phase advection, solid-phase sorption, gas diffusion in the vapor phase,
and three-phase equilibrium. The contaminant mass within each model cell is partitioned among liquid
(dissolved in water), vapor, and solid phases. The model assumes a homogeneous porous medium with
steady flow and no dispersion. There is no in-situ degradation or production, and free product is not
present. Input data for VLEACH consists of: organic carbon coefficient (Koc), Henry's Law constant (Kh),
the aqueous solubility and the free air diffusion coefficient. The input soil properties are dry bulk density,
total porosity, volumetric water content and organic carbon fraction, and site-specific input parameters such
as recharge rate and depth to groundwater.
Contact Address: Center for Subsurface Modeling Support (CSMOS), R.S. Kerr Environm. Res. Lab.,
U.S. EPA, P.O. Box 1198, Ada, OK 74820; or Internal. Ground Water Modeling Ctr.,
Colorado Sch. of Mines, Golden, CO 80401
C.4-1-12
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Appendix C.4, part 1 (continued)
IGWMC Key: 5850 Model Name: RZWQM Released: 1990
Authors: DeCoursey, D.G., K.W. Rojas, and LR. Ahuja
RZWQM (Root Zone Water Quality Model) is a physically based model simulating the movement of water,
nutrients, and pesticides over and through the root zone at a representative point in a field. The physical
processes included are soil matrix infiltration, macropore flow, surface runoff, heat flow, potential
evaporation, and transpiration, soil-water redistribution and chemical transport. Root water uptake, actual
evaporation and transpiration, are calculated in the crop growth section in conjunction with water
redistribution and plant growth. Soil chemical processes include bicarbonate buffering, dissolution and
precipitation of calcium carbonate, gypsum, and aluminum hydroxide, ion exchange involving bases and
aluminum, and solution chemistry of aluminum hydroxide. RZWQM also includes various nutrient processes
such as decomposition of organic matter, mineralization, immobilization and demineralization of appropriate
nitrogen and phosphorus species, and adsorption/desorption of both species. Pesticide processes the
model can handle include computation of the amount of pesticides reaching the soil surface, and the
amounts absorbed and moving through each soil layer. Dissipation via volatilization, photolysis, hydrolysis,
biodegradation, oxidation, and complexation are simulated. These processes may be lumped in a single
process. Other pesticide related processes simulated in RZWQM are dissipation by formulation of
metabolites (tracked throughout their life time). Either equilibrium isotherms or kinetic adsorption/desorption
processes may be simulated. The model allows to include certain management practices such as effects
of tillage practices on chemical distribution, soil density, and macro- and microporosity; fertilizer and
pesticide applications; planting densities; and irrigation and drainage practices.
Contact Address: LR. Ahuja, USDA Agric. Res. Service, P.O. Box E, Fort Collins, CO 80522
IGWMC Key: 5860 Model Name: NEWTMC Released: 1985
Authors: Lindstrom, FT., and FT. Piver
NEWTMC is an one-dimensional mass balance model for simulating the transport and fate of nonionizable
organic compounds in unsaturated/saturated porous media. Using the principles of water mass,
momentum, heat energy and chemical mass balance, the model solves simultaneously for moisture,
temperature and liquid phase chemical concentration. The model uses a dynamic free boundary to
represent the air-soil interface and a prescribed water table height as lower boundary. The model allows
for elaborate simulation of air conditions at the air-soil interface, allowing the boundary conditions to be
dependent on the air conditions. Chemicals may be introduced via incoming air (vapor phase), rain water,
inflow from the water table, or initially distributed within the soil column.
Contact Address: Lindstrom, FT., Dept. of Mathematics, Oregon State Univ., Corvallis, OR 97331
IGWMC Key: 6130 Model Name: PESTAN Released: 1990
Authors: Enfield, C.G., R.F. Carsel, S.Z. Cohen, and T. Phan
PESTAN (PESticide Analytical Model) is an interactive analytical model, used for estimating organic chemical
movement in the unsaturated zone. The model is based on an analytical solution of the convective dispersive
solute transport equation for single layer homogeneous soils. It calculates vertical convective movement of
chemicals with linear equilibrium sorption and first-order (bio-) chemical decay. Hydrologic loading is based
on annual water balance. The primary application has been for pesticide screening.
Contact Address: Center for Subsurface Modeling Support (CSMOS), R.S. Kerr Environm. Res. Lab.,
U.S. EPA, P.O. Box 1198, Ada, OK 74820; or Internat. Ground Water Modeling Ctr.,
Colorado Sch. of Mines, Golden, CO 80401.
C. 4-1-13
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 6225 Model Name: CHAIN Released: 1985
Author: van Genuchten, M. A.
The CHAIN model simulates multi-ion transport across the unsaturated zone using an analytical procedure.
The model includes longitudinal dispersion and first-order decay. It calculates the time history of chemical
concentration exiting the unsaturated zone.
Contact Address: M.Th. van Genuchten, U.S. Salinity Lab., Agricultural Res. Service, 4500 Glenwood
Drive, Riverside, CA 92501
IGWMC Key: 6229 Model Name: HYDRUS/WORM Released: 1992
Authors: Kool, J.B., M.Th. van Genuchten
HYDRUS is a Galerkin linear finite element program for simulation of transient one-dimensional flow and
solute transport in variably saturated porous media. The solution of the flow problem considers the effects
of root uptake and hysteresis in the soil hydraulic properties. The solute transport equation incorporates
the processes of ionic or molecular diffusion, hydrodynamic dispersion, linear or nonlinear equilibrium
adsorption, and first-order decay. Boundary conditions for the flow and transport may be constant or
time-varying. For flow boundary conditions, HYDRUS can solve the steady-state flow equation in a single
step without the need of performing time-marching. The HYDRUS program is a modification of the WORM
program developed at the U.S. Salinity Laboratory.
The solution of the flow equation in HYDRUS requires specification of the initial condition in terms of
pressure head or water content. Either first- or second-type boundary conditions can be imposed at the
soil surface. Alternatively, the upper boundary condition may be specified in terms of total amount of
surface applied water, combining both types of boundary conditions. The auxiliary condition at the lower
boundary is given in terms of imposed pressure head, zero head gradient, or imposed net drainage flux.
Type of boundary condition might change in time.
Soil hydraulic properties in HYDRUS can be described by the parametric functions of Van Genuchten (1978).
Uptake of water by plant roots includes evapotranspiration, a normalized root uptake distribution function,
and a pressure-salinity stress response function. HYDRUS uses the fully-implicit scheme to solve the set
of matrix equations for flow and transport. Nonlinearities in the flow equations are treated using Picard
iteration with under-relaxation. For solute transport, corrections are applied to the dispersion coefficient to
reduce numerical problems.
Contact Address: M.Th. van Genuchten, U.S. Salinity Lab., Agricultural Res. Service, 4500 Glenwood
Drive, Riverside, CA 92501
IGWMC Key: 6390 Model Name: MOUSE Released: 1984
Authors: Pacenka, S., and T. Steenhuis
MOUSE (Method Of Underground Solute Evaluation) is developed for classroom and Cooperative Extension
Service educational purposes. The model tracks soluble chemical movement in both the saturated and the
unsaturated zone by coupling 1D vertical flow and transport in three-layer soils with 2D cross-sectional flow
and transport in an anisotropic, heterogeneous aquifer. Surface runoff is calculated using the USDA Soil
Conservation Service curve number equation. Active evapotranspiration occurs in the top layer of the soil.
The finite difference model includes first-order degradation, dispersion, diffusion and convective mass
movement. Furthermore, the model can handle linear equilibrium adsorption/desorption isotherms.
Contact Address: T. Steenhuis, Cornell Univ., Agricult. Eng. Dept., Ithaca, New York 14853
C.4-1-14
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 6620 Model Name: RITZ Released: 1988
Authors: Nofziger, D.L, J.R. Williams, and I.E. Short
RITZ (Regulatory and Investigative Treatment Zone model) is an interactive program for simulation of the
movement and fate of hazardous chemicals during land treatment of oily wastes. The model considers a
constant water flux and downward movement of the pollutant with the soil solution (leaching), volatilization
and loss to the atmosphere, and (bio-)chemical degradation. The treatment site modeled consists of a plow
zone and a treatment zone. The model incorporates the influence of oil upon the transport and fate of the
pollutant. As input the model requires the properties of the chemicals and oil in the waste material, the soil
properties of the treatment site, the management practices, and the parameters relevant to the environment
of the site.
Contact Address: J.R. Williams, R.S. Kerr Environm. Res., U.S. EPA, P.O. Box 1198, Ada, OK 74820
IGWMC Key: 6640 Model Name: CHEMRANK Released: 1988
Authors: Nofziger, D.L, P.S.C. Rao, and A.G. Hornsby
CHEMRANK is an interactive package which utilizes four ranking schemes for screening organic chemicals
relative to their potential to leach into groundwater systems. The schemes are based on rates of chemical
movement or relative rates of mobility and degradation of the chemicals within the vadose zone. Two
schemes use steady state groundwater recharge rates and the other two require daily rainfall and
evaporation data. The latter two schemes rank chemical mobility by travel time in the vadose zone or mass
emission of selected chemicals at some specified depth in the vadose zone.
Contact Address: Inst. of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611
IGWMC Key: 6710 Model Name: CMIS (Chemical Movement in Soil) Released: 1986
Authors: Nofziger, D.L, and A.G. Hornsby
CMIS is a management/educational computer program that provides qualitative predictions of pesticide fate
as function of key soil, chemical, and climatic variables. Model assumptions limit it to nonpolar pesticides
(and other xenobiotics) moving in sandy soils. Linear adsorption/desorption isotherms are used to describe
chemical affinity to the soil matrix.
Contact Address: Inst. of Food and Agric. Sciences, IFAS, University of Florida, Building 664,
Gainesville, FL 32611
IGWMC Key: 6711 Model Name: CMLS (Chemical Movement in Layered Soil$eleased: 1988
Authors: Nofziger, D.L, and A.G. Hornsby
CMLS is an interactive microcomputer model to be used as management tool and a decision aid in the
application of organic chemicals to soils. The model estimates the location of the peak concentration of
non-polar organic chemicals as they move through a soil in response to the downward movement of water.
The model also estimates the relative amount of each chemical still in the soil at any time. The model can
deal with soils with up to 20 layers or horizons, each having its own partition coefficient and degradation
half-life of the chemical of interest.
Contact Address: Inst. of Food and Agric. Sciences IFAS, University of Florida, Building 664,
Gainesville, FL 32611
C. 4-1-15
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 6712 Model Name: CHEMFLO Released: 1989
Authors: Nofziger, D.L, KRajender, S.K. Nayudu, and P-Y. Su.
CHEMFLO is an interactive program for simulating water and chemical movement in unsaturated soils.
Water movement is modeled using the Richards equation. Chemical transport is modeled by means of the
convection-dispersion equation. These equations are solved numerically for one-dimensional flow and
transport using finite differences. Results of the flow model can be displayed in the form of graphs of water
content, matric potential, driving force, conductivity, and flux density of water versus distance or time.
Graphs of concentration, and flux density of chemical as function of distance or time can also be displayed.
CHEMFLO is an expansion and update of the water movement model WATERFLO by Nofziger (1985).
CHEMFLO is an extension and update of WATERFLO by Nofziger (1985; see IGWMC key # 6630). Soil and
chemical parameters required by the model include: soil bulk density, water-soil partition coefficient, diffusion
coefficient of chemical in water, dispersivrty, first-order degradation rates for contaminant in the water and
the solid phases, and a zero order rate constant for the liquid. Other parameters required for solving the
Richards equation are the function relationships for soil-water retention and unsaturated hydraulic
conductivity.
Contact Address: J.R. Williams, R.S. Kerr Environm. Res. Lab., U.S. EPA, Ada, Oklahoma 74820
C.4-1-16
-------
Appendix C.4: Solute Transport; Models for Unsaturated Zone, Part 2: Usability and Reliability
IGWMC
Key
583
2891
2892
3234
3235
3238
3371
3411
3432
3450/
3451
3540
3541
3830
4081
4140
4270
4290
4350
4391
4570
Model
SATURN
GS2
GS3
VADOSE
FLOTRA
PORFLOW-3D
FEMWASTE/
FECWASTE
LEACHM(-P)
CXTFIT
DISPEQ/
DISPER/PISTON
CREAMS
GLEAMS
SUTRA
TRIPM
MLSOIL/DFSOIL
TRACR3D
CADIL/AGTEHM
FEMTRAN
SBIR
VS2D/VS2DT
Usability
Preprocessor
N
U
U
Y
Y
Y
N
Y
Y
N
Y
Y
Y
U
U
U
U
U
U
Y
0
1C
a
a.
(0
o
Q.
N
U
U
Y
Y
Y
N
Y
Y
N
Y
Y
Y
U
U
U
U
U
U
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
Y
Y
Y
N
Y
Y
N
N
N
N
N
U
U
U
U
U
N
S
0.
Q.
N
N
N
Y
Y
Y
Y
L
Y
N
L
L
L
N
U
U
U
U
U
L
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
N
U
U
U
Verified
L
L
L
L
L
E
E
E
L
L
E
E
L
L
U
L
L
L
E
L
•o
$
o
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iZ
L
L
L
L
L
L
L
L
U
U
L
L
L
U
U
U
U
U
U
L
Model Users
F
F
F
F
F
F
M
M
M
F
M
M
M
F
U
U
U
U
U
M
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.4-2-1
-------
Appendix C.4, part 2 (continued)
IGWMC
Key
4630
4690
4691
4693
4720
4721
4931
4934
5021
5028
5031
5039
5186
5213
5220
5310
5500
Model
FLAMINGO
VAM2D
VAM3D
VADOFT
PRZM
RUSTIC
TARGET-2DU
TARGET-SOU
BIOSOIL
GTC
CTSPAC
SESOIL
NITRO
TDF10
VSAFT2
PRZMAL
BIO1D
Usability
Preprocessor
N
Y
Y
U
Y
U
Y
Y
N
U
U
Y
Y
U
Y
Y
Y
o
«
k
a
8
a.
N
Y
Y
U
Y
U
Y
Y
N
U
U
Y
Y
U
Y
Y
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
N
Y
U
Y
Y
N
U
U
Y
Y
Y
Y
Y
Y
4*
O
a.
*
a>
N
L
L
L
L
U
Y
Y
N
U
U
Y
Y
L
L
L
L
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
U
U
U
U
N
U
U
U
U
U
U
U
Verified
E
E
E
E
E
L
L
L
L
L
L
L
L
L
L
L
L
•o
S
f
TJ
tl
L
L
L
L
L
U
U
U
U
U
U
L
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U
U
U
L
«
0
i
o
F
F
F
F
M
U
U
U
F
U
U
M
U
U
U
F
F
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C.4-2-2
-------
Appendix C.4, part 2 (continued)
IGWMC
Key
5630
5661
5681
5690
5850
5860
6130
6225
6229
6390
6620
6640
6710
6711
6712
Model
MULTIMED
FLAME
VIP
VLEACH
RZWQM
NEWTMC
PESTAN
CHAIN
HYDRUS/WORM
MOUSE
RITZ
CHEMRANK
CMIS
CMLS
CHEMFLO
Usability
Preprocessor
Y
N
Y
N
Y
N
Y
N
Y
Y
Y
Y
Y
Y
Y
&
tt
w
Q.
<0
I
Y
N
Y
N
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
Y
U
Y
Y
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
1
a.
a
«
L
U
Y
L
Y
N
L
N
Y
Y
Y
Y
Y
Y
Y
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
N
U
U
U
U
U
U
U
U
U
Verified
L
E
L
L
E
L
L
L
L
L
L
L
L
L
L
Field Tested
U
U
U
U
L
N
L
U
U
u
u
u
u
u
u
£
3
"o
•o
o
s
M
U
F
U
F
F
M
U
F
U
M
M
M
M
M
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
C. 4-2-3
-------
Appendix D: Heat Transport Models, Part 1: Model Description
IGWMC Key: 0100 Model Name: PT/CCC Released: 1981
Authors: M.J. Lippmann, T.N. Narasimhan, D.C. Mangold and G.S. Bodvarsson
PT/CCC is a integrated finite difference method to calculate steady and unsteady temperature and pressure
distributions, and vertical compaction in multidimensional heterogeneous systems with complex geometry
and a single phase, non-isothermal liquid.
Contact address: Nat. Energy Software Center, Argonne Nat. Lab., 9700 South Cass Avenue,
Argonne, IL 60439
IGWMC Key: 0160 Model Name: SCHAFF Released: 1976
Authors: M.L Sorey and M.J. Lippmann
SCHAFF is a three-dimensional finite difference model to simulate coupled unsteady heat transport and fluid
flow in slightly compressible heterogeneous porous media.
Contact address: Nat. Energy Software Center, Argonne Nat. Lab., 9700 South Cass Avenue,
Argonne, IL 60439
IGWMC Key: 0513 Model Name: GAFETTA Released: 1980
Authors: G.F. Finder, P.E. Kinnmark and C.I. Voss
GAFETTA is a two-dimensional finite element model intended to simulate thermal energy transport in
confined and unconfined aquifers with horizontal non-density dependent ground water flow. The model
computes the distribution of hydraulic head and temperature in an anisotropic, heterogeneous aquifer and
allows analysis of temperature changes in over- and underlying layers due to pumping or injection wells,
artificial or natural infiltration of hot or cold water, steady leakage of hot or cold water from adjacent aquifers,
connection with lakes and rivers, and changing air temperature.
Contact address: C.I. Voss, U.S. Geological Survey, Water Resources Division, 431 National Center,
Reston, VA 22092
IGWMC Key: 0581 Model Name: FTRANS Released: 1982
Author: P.S. Huyakorn
FTRANS is a 2-D finite-element model to simulate transient, saturated single phase ground water flow, heat
transport, and chemical or radionuclide transport in fractured or unfractured, anisotropic, heterogeneous,
multilayered porous media. For any type of fractured system, the flow and transport analysis are performed
taking into account interaction between the porous matrix and the fractures. The analyses are made in the
main areal flow plane, in a vertical cross-section, or in an axisymmetric configuration. The code fully
accounts for fluid leakages, hydrodynamic dispersion, sorption, first-order decay, chain reactions, and solute
diffusion and heat conduction in the porous matrix, coupled thermal fluid capability and density-dependent
flow and solute transport.
Contact address: Performance Assessment Dept., Office of Nuclear Waste Isolation, Battelle Project
Management Division, 505 King Avenue Columbus, Ohio 43201
D-1-1
-------
Appendix D, table 1 (continued)
IGWMC Key: 0582 Model Name: GREASE Released: 1982
Author: P.S. Huyakorn
GREASE 2 is a multi-purpose finite element model to simulate transient, multi-dimensional, saturated
groundwater flow, solute and/or energy transport in fractured and unfractured, anisotropic, heterogeneous,
multilayered porous media. The analysis can be performed for confined, semiconfined, or unconfined
groundwater reservoir systems. Fluid leakage or heat transfer between the aquifer and its confining layer
can be taken into account. The model allows for analysis of areal flow, vertical cross-sectional flow or flow
in an axisymmetric configuration. Coupled thermal fluid flow capability, and density dependent flow and
solute transport capability area also available. Sorption and decay can be included in the solute transport
analysis.
Contact address: GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 0588 Model Name: SEFTRAN Released: 1986
Authors: P.S. Huyakorn, D.S. Ward, J.O. Rumbaugh III and R.W. Broome
SEFTRAN (Simple and Efficient Flow and TRANsport model) is a concise finite element model to simulate
transient two-dimensional fluid flow and transport of non-conservative contaminants or heat in isotropic,
heterogeneous aquifers. It can solve the flow and transport equations in an areal plane, a vertical
cross-section, or an axisymmetric configuration. Line elements may be used to simulate discrete fractures
or rivers.
Contact address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 0612 Model Name: HOTWTR Released: -1985
Author: J.E. Reed
HOTWTR is a three-dimensional finite-difference model to simulate steady-state coupled water and heat flow
in an isotropic, heterogeneous aquifer system with uniform thermal properties and viscosity dependent
hydraulic conductivity.
Contact address: J.E. Reed, U.S. Geological Survey, P.O. Box 25046, MS 417, Federal Center,
Denver, CO 80225
IGWMC Key: 0696 Model Name: BORHOL Released: 1984
Authors: L.D. Rickertsen, C.J. Noronha and M. Reeves
BORHOL is a finite difference model that treats the case of an open borehole through a salt formation
connecting two aquifers, and determines the borehole radius as a function of depth and time. Within the
borehole, the model treats the transient, one-dimensional coupled processes of flow, heat transport and
volume modification subject to the mechanism of salt dissolution, precipitation and creep. Within the rock
formation, the model simulates three-dimensional transport of heat from a nuclear waste repository since
both creep and convective heat transfers to the fluid depends upon the rock temperature.
Contact address: Performance Assessment Department, Office of Nuclear Waste Isolation, Battelle
Project Management Division, 505 King Avenue, Columbus, OH 43201
D-1-2
-------
Appendix D, table 1 (continued)
IGWMC Key: 0697 Model Name: SWENT Released: 1983
Authors: R.B. Lantz, S.B. Pahwa and B.S. RamaRao
SWENT (Simulator for Water, Energy, and Nuclide Transport) is a finite difference model for simulation of
transient, multidimensional transport of fluid, energy, a single inert chemical species, and any number of
radionuclides in straight or branched chains, through a heterogeneous, anisotropic geological medium. Flow
and transport are coupled through density and viscosity. Aquifer porosity is treated as function of pressure.
The code has options to simulate any one of the individual processes or a combination of the processes.
It offers a wide choice of boundary conditions. The model permits the choice of backward or central
difference approximations. Either direct or iterative methods may be used for solving the matrix equations.
Contact address: Performance Assessment Department, Office of Nuclear Waste Isolation, Battelle
Project Management Division, 505 King Avenue, Columbus, OH 43201
IGWMC Key: 0730 Model Name: GEOTHER Released: 1983
Authors: C.R. Faust and J.W. Mercer
GEOTHER is a finite difference model for simulation of transient three-dimensional, single and two-phase
heat transport in anisotropic, heterogeneous, porous media. It is based on the continuity equations for
steam and water, which are reduced to two nonlinear partial differential equations in which the dependent
variables are fluid pressure and enthalpy. The nonlinear coefficients in the equations are calculated using
Newton-Raphson iterations, and an option is provided for using either upstream or midpoint weighing on
the mobility terms. GEOTHER may be used to simulate the fluid-thermal interaction in rock that can be
approximated by a porous media representation. It can simulate heat transport and flow of compressed
water, two-phase mixtures, and super-heated steam.
Contact address: Performance Assessment Department, Office of Nuclear Waste Isolation, Battelle
Project Management Division, 505 King Avenue, Columbus, Ohio 43201
IGWMC Key: 2034 Model Name: SHALT Released: 1980
Authors: J.F. Pickens and G.E. Grisak
SHALT is a finite element model that simulates heat and solute transport in a fractured, saturated or
unsaturated, two-dimensional groundwater flow system. The model simulates density dependent
compressible fluid flow; heat convection, conduction and dispersion; solute advection, dispersion and linear
equilibrium adsorption; radioactive decay; and various first-order chemical reactions.
Contact address: Intera Technologies, Inc. 6850 Austin Center Blvd., Suite # 300, Austin, TX 78731
IGWMC Key: 2070 Model Name: CFEST Released: 1987
Authors: S.K. Gupta, C.T. Kincaid, P.R. Meyer and C.R. Cole
CFEST is a three-dimensional finite element model for simulation of steady-state or transient, single-phase
Darcian flow, and energy and solute transport in anisotropic, heterogeneous, multi-layered aquifers. The
code has the capability to model discontinuous and continuous layering and time-dependent and constant
sources/sinks. The partial differential equations for pressure, temperature, and solute concentration are
coupled with fluid properties of density and viscosity. The relationship between porosity and pore-pressure
is also accounted for. The model comes with various programs for data input, gridding and post-processing
including streamline generation and contouring. It has a restart option and data error checking.
Contact address: C. Cole, Battelle Pacific NW Lab., P.O. Box 999, Richland, WA 99352
D-1-3
-------
Appendix D, table 1 (continued)
IGWMC Key: 2580 Model Name: SHAFT Released: 1980
Authors: K. Pruess and R.C. Schroeder
SHAFT is a two-phase geothermal reservoir simulator. It uses the integrated finite difference technique for
transient simulation of simultaneous three-dimensional heat and fluid transport in porous media. The model
handles condensation, heat convection, heat conduction and phase changes.
Contact address: Nat. Energy Software Center, Argonne Nat. Lab., 9700 South Cass Avenue,
Argonne, IL 60439
IGWMC Key: 2581 Model Name: MULKOM Released: 1985
Author: K. Pruess
MULKOM is an integrated finite difference model to simulate multi-component, multi-phase fluid and heat
flow in porous or fractured media. The model incorporates convection, change of phase, dissolution and
precipitation of silica, equilibration of noncondensible gases, transport of noncondensible gases and
dissolved solids.
Contact address: K. Pruess, Lawrence Berkeley Lab., Earth Sciences Div., M.S. 50E LBL, Univ. of
California, Berkeley, CA 94720
IGWMC Key: 2582 Model Name: TOUGH Released: 1987
Authors: K. Pruess, Y.W. Tsang and J.S.Y. Wang
TOUGH is a multi-dimensional integrated finite difference model for transient simulation of the coupled
transport of water, air, vapor and heat transport in fractured unsaturated porous media. The model includes
convection, condensation, capillary forces, evapotranspiration, heat conduction and diffusion, change of
phase, adsorption, fluid compression, dissolution of air in liquid, and buoyancy.
Contact address: K. Pruess, Lawrence Berkeley Lab., Earth Science Div., M.S. 50E LBL, Univ. of
California, Berkeley, CA 94720
IGWMC Key: 2620 Model Name: MARIAH Released: 1980
Authors: O.K. Gartling and C.E. Hickox
MARIAH is a finite element model to simulate steady or non-steady state two-dimensional fluid flow in
saturated porous media including the effects of heat transfer. The specific types of flow problems for which
MARIAH is suitable include isothermal flows, forced convection, free convection, and mixed convection. The
porous matrix is considered homogeneous and rigid. For non-isothermal flows, the fluid and matrix are
assumed to be in thermal equilibrium. Buoyancy driven flows are assumed to follow the Boussinesq
approximation. MARIAH is a self-contained analysis program with its own mesh-generator, data
analysis and plotting packages.
Contact address: O.K. Gartling, Sandia National Lab., Fluid Mechanics and Heat Transfer Division I,
5511, Albuquerque, NM 87185
D-1-4
-------
Appendix D, table 1 (continued)
IGWMC Key: 2760 Model Name: MUSHRM Released: 1980
Author: J.W. Pritchett
MUSHRM is a hydrothermal finite difference reservoir model to simulate unsteady multi-phase fluid and heat
flow in multi-dimensional geometries including 3-D. The program handles convection, conduction, change
of phase and degassing phenomena.
Contact address: J.W. Pritchett, Systems, Science and Software, P.O. Box 1620, La Jolla, CA 92038
IGWMC Key: 2761 Model Name: CHARGR Released: 1980
Author: J.W. Pritchett
CHARGR is a three-dimensional multi-phase compressible liquid simulator for transient, multi-phase fluid flow
with dissolved incondensable gases, and heat transport in anisotropic, heterogeneous deformable porous
media. It uses the finite difference method to predict pressures and temperatures.
Contact address: J.W. Pritchett, Systems, Science and Software, P.O. Box 1620, La Jolla, CA 92038
IGWMC Key: 2830 Model Name: GWTHERM Released: 1979
Authors: A. Runchal, J. Treger, G. Segal
GWTHERM is a two-dimensional integrated finite difference model for cross-sectional or radial symmetric
simulation of fluid flow, heat and solute transport in an anisotropic, heterogeneous, water table aquifer with
density- and temperature-dependent fluid properties.
Contact address: Dames and Moore, Advanced Technology Group, 1100 Glendon Avenue - Suite
1000, Los Angeles, CA 90024
IGWMC Key: 2860 Model Name: UWIS-2D-TRANSPORT Released: 1980
Author: C.B. Andrews
UWIS-2D-TRANSPORT is a finite element model to simulate two-dimensional, areal or cross-sectional, steady
or transient, single-phase heat flow or conservative mass transport in a confined or phreatic, anisotropic,
heterogeneous aquifer.
Contact address: C. Andrews, S.S. Papadopulos & Assoc., 7944 Wisconsin Ave, Bethesda, MD 20814
IGWMC Key: 2950 Model Name: TRANS Released: 1981
Authors: W.R. Walker, J.D. Sabey and D.R. Hampton
TRANS is a finite element model for transient simulation of two-dimensional, horizontal, cross-sectional, or
axial symmetric, coupled flow of heat and moisture in partially or fully saturated porous media, especially
for assessment of buried thermal reservoirs and the heat exchange piping internal to the reservoirs.
Contact address: D. Hampton, Western Michigan Univ., Geology Dept., Kalamazoo, Ml 49008
D-1-5
-------
Appendix D, table 1 (continued)
IGWMC Key: 3083 Model Name: ROCMAS-THM Released: -
Authors: J. Noorishad and P.A. Witherspoon
ROCMAS-THM is a two-dimensional model for coupled hydraulic-thermal-mechanical analysis of porous
fractured rock.
Contact address: J. Noorishad, Lawrence Berkeley Labor., Earth Sciences Div., Univ. of Calif.,
Berkeley, CA 94720
IGWMC Key. 3084 Model Name: CHNTRNS Released: 1987
Authors: J. Noorishad, C.L Carnahan and LV. Benson
CHMTRNS is a temperature-dependent non-equilibrium reactive chemical transport code, based on the
CHEMTRN code (Miller and Benson) developed in the early 1980's. Equations solved include mass balance,
aqueous species transport, non-equilibrium reactions, transport of hydrogen and hydroxide ions, equilibrium
complexation, dissolution and precipitation, ion exchange, redox reactions, and heat transport. The code
is capable of simulating kinetic calcite and silicate dissolution, irreversible glass dissolution, oxidation and
reduction, and stable carbon isotope fractionation during transport. The code can handle Neumann and
Dirichlet boundary conditions and includes a mesh generation scheme. The 1-D transport equation is solved
using a upstream weighted finite difference algorithm.
Contact address: J. Noorishad, Lawrence Berkeley Labor., Earth Sciences Div., Univ. of Calif.,
Berkeley, CA 94720
IGWMC Key: 3232 Model Name: FRACFLOW Released: 1981
Author: B. Sagar, B.
FRACFLOW is an integrated finite difference model for steady and nonsteady state analysis of coupled,
density-dependent flow, heat and mass transport in fractured confined aquifers. The processes in the
porous medium are simulated in two dimensions and in the fractures in one dimension. Fractures may have
arbitrary orientations. Any number of fractures, each of different properties may be incorporated. The
program includes first-order chemical reactions. A preprocessor and a number of graphic post-processing
routines are available.
Contact address: Rockwell Hanford Qper., P.O. Box 800, Richland, WA 99352
IGWMC Key: 3233 Model Name: PORFLOW - II (2D) Released: 1988
Authors: A.K. Runchal
PORFLOW II (2D) is an integrated finite difference model for analysis of coupled, steady-state or transient,
2-dimensional horizontal, vertical or radial, density dependent flow and heat and/or mass transport in
anisotropic, heterogeneous, non-deformable saturated porous media with time dependent aquifer and fluid
properties. User interface is based on the FREEFORM language with simple English commands.
Contact address: Analytical & Computational Research, Inc., 1931 Stradella Road, Bel Air, CA 90077.
D-1-6
-------
Appendix D, table 1 (continued)
IGWMC Key: 3234 Model Name: VADOSE Released: -1982
Author: B. Sagar
VADOSE is an integrated finite difference model for analysis of steady or transient, two-dimensional areal,
cross-sectional or radial simulation of coupled, density-dependent transport of moisture, heat and solutes
in variably-saturated, heterogeneous, anisotropic porous media.
Contact address: Rockwell Hanford Operations, P.O. Box 800, Richland, WA 99352
IGWMC Key: 3235 Model Name: FLOTRA Released: 1982
Authors: B. Sagar
FLOTRA is an integrated finite difference model for simulation of steady or transient, two-dimensional areal,
cross-sectional or radial, density- dependent flow, heat and mass transport in variably saturated, anisotropic,
heterogeneous deformable porous media.
Contact address: Rockwell Hanford Operations, P.O. Box 800, Richland, WA 99352
IGWMC Key: 3236 Model Name: PORFREEZE Released: 1981
Author: A.K. Runchal
PORFREEZE simulates steady-state or transient two-dimensional density-dependent saturated flow and heat
transport in freezing soils. The coupled equations are solved with the finite difference method and include
time and temperature dependency of fluid and aquifer properties.
Contact address: Analytic & Computational Research, Inc., 1931 Stradella Road, Bel Air, CA 90077
IGWMC Key: 3238 Model Name: PORFLOW-3D Released: 1991
Author: A.K. Runchal
PORFLOW-3D is an integrated finite difference model to simulate coupled transient or steady-state,
multiphase, fluid flow, and heat, salinity, or chemical species transport in variably saturated porous or
fractured, anisotropic and heterogeneous media. The program facilitates arbitrary sources or sinks in
three-dimensional cartesian or axisymmetric (cylindrical) geometry. The user interface is based on the
FREEFORM language using simple English-like commands. The software includes the ARCPLOT graphic
post processor.
Contact address: Analytic and Computational Research, Inc., 1931 Stradella Road, Bel Air, CA 90077
IGWMC Key: 3375 Model Name: MATTUM Released: 1983
Authors: G.T. Yeh and R.J. Luxmoore
MATTUM is a three-dimensional model for simulating moisture and thermal transport in unsaturated porous
media. The model solves both the flow equation and the heat transport equation under unsaturated water
conditions using the integrated compartment method. The entire unsaturated zone is divided in a number
of compartment of different sizes and shapes. The Philip-de Vries equations governing moisture movement
and heat transfer are integrated over each of the compartments to yield a system of nonlinear ordinary
differential equations. There three optional time integration schemes: split explicit, implicit pointwise iteration,
and matrix inversion iteration.
Contact address: Oak Ridge Nat. Lab., Environmental Sciences Div., Oak Ridge, TN 37830
D-1-7
-------
Appendix D, table 1 (continued)
IGWMC Key: 3590 Model Name: SPLASHWATER Released: 1983
Author: P.C.D. Milly
SPLASHWATER is a finite element model for simulation of coupled heat and moisture fields in the
unsaturated zone. The model includes evapotranspiration, hysteresis, and heat convection and conduction.
Contact address: P.C.D. Milly, Princeton University, Dept. of Civil Engineering, Princeton, NJ 08544
IGWMC Key: 3790 Model Name: PORFLO Released: 1985
Authors: A.K. Runchal, B. Sagar, R.G. Baca and N.W. Kline
PORFLO is an integrated finite difference model for transient two-dimensional or axisymmetric simulation
of coupled buoyancy driven groundwater flow, heat transfer and radionuclide transport in layered geologic
systems. Heat transfer processes include storage, advection, conduction, dispersion and heat generation.
Fluid flow processes include storage, inflows and outflows, pore pressure buildup, buoyancy driving force
and temperature dependent hydraulic conductivity. Mass transport processes include storage, advection,
dispersion and diffusion, retardation, decay and mass release.
Contact address: N.W. Kline, Boeing Computer Services Richland, P.Q Box 300, Richland. WA 99352
IGWMC Key: 3830 Model Name: SUTRA Released: 1990
Author: C.I. Voss
SUTRA (Saturated-Unsaturated TRAnsport) simulates transient or steady-state, two-dimensional, variably
saturated, fluid density dependent ground water flow with transport of energy or chemically reactive species
solute transport. The model employs a hybrid finite-element and integrated-finite-difference method to
approximate the coupled equations. Solute transport include advection, dispersion, diffusion, equilibrium
adsorption on the porous matrix, and both first-order and zero-order decay or production. Energy transport
may take place in both the solid matrix and the liquid phase. SUTRA may be employed in both areal
(horizontal) and cross-sectional mode for saturated systems or in cross-sectional mode only for unsaturated
systems.
Contact address: C.I. Voss, C.I., U.S. Geological Survey, 431 National Center, Reston, VA 22092;
Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401,
or Scientific Software, Washington, D.C.
IGWMC Key: 3840 Model Name: SWIFT Released: 1981
Authors: R.T. Dillon, R.M. Cranwell, R.B. Lantz and S.B. Pahwa
SWIFT (Sandia Waste-Isolation Flow and Transport) is a three-dimensional finite difference model for
simulation of coupled, transient, density dependent flow and transport of heat, brine, tracers or radionuclides
in heterogeneous, anisotropic, saturated porous media.
Contact address: R.M. Cranwell. Sandia National Laboratories, Albuquerque, NM 87185
IGWMC Key: 3841 Model Name: SWIFT II Released: 1S87
Authors: M. Reeves, D.S. Ward, J.D. Johns and R.M. Cranwell
SWIFT II is a three-dimensional finite difference model for simulation of steady-state or transient flow and
transport of fluid, heat, brine, and radionuclide chains in confined or unconfined (fractured) porous media.
continued
D-1-8
-------
Appendix D, table 1 (continued)
SWIFT II - continued
The equations for fluid, heat, and brine are coupled by fluid density, fluid viscosity, and porosity. Both
dual-porosity and discrete-fractures might be considered. Only one-dimensional migration is permitted in
the rock matrix. The model includes a salt dissolution mechanism and a waste leaching algorithm.
Moreover, SWIFT II has a well-bore submodel and handles both radial and cartesian coordinates. Among
the many boundary conditions which can be used is a free phreatic surface condition.
Contact address: D.S. Ward, GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 3842 Model Name: SWIFT HI/386 Released: 1992
Authors: D.S. Ward
SWIFT Ml/386 is a fully transient, three-dimensional model which simulates the flow and transport of fluid,
heat (energy), brine, and radionuclide chains in porous and fractured geologic media. The primary
equations for fluid, heat, and brine are coupled by fluid density, fluid viscosity, and porosity. Both Cartesian
and cylindrical coordinate systems may be used. For the fracture zone the model allows both dual-porosity
and discrete fractures. Migration within the rock matrix is characterized as a one-dimensional process.
Aquifer hydraulic characteristics may be heterogeneous and anisotropic under confined or unconfined
conditions. The discretization is performed by the finite difference method using centered or backwards
weighing in time and space.
Contact address: P.S. Ward, GeoTrans, Inc.. 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 3860 Model Name: DFT/C-1D Released: 1984
Author: C.S. Desai
DFT/C-1D is a finite element model for one-dimensional analysis of linear stress-deformation (consolidation)
and steady-state or transient fluid flow. The model calculates matrix displacement, fluid head, temperature
and pore water pressure.
Contact address: C.S. Desai, Univ. of Arizona, Dept. of Civil Eng. and Mech. Eng., Tuscon, AZ 85721
IGWMC Key: 3861 Model Name: FIELD-2D Released: --
Author: C.S. Desai
FIELD-2D is a finite element model for analysis of linear steady state two-dimensional problems in torsion,
potential flow, seepage and heat flow.
Contact address: C.S. Desai, Univ. of Arizona, Dept. of Civil Eng. and Mech. Eng., Tuscon, AZ 85721
IGWMC Key: 3890 Model Name: PT (Pressure-Temperature) Released: 1986
Author: G.S. Bodvarsson
PT is a three-dimensional integrated finite difference model for simulation of three-dimensional, transient,
single phase fluid flow with simultaneous heat transport and one-dimensional subsidence in isotropic,
heterogeneous porous media.
Contact address: G.S. Bodvarsson, Lawrence Berkeley Lab., Earth Sciences Div., Univ. of California,
Berkeley, CA 94720
D-1-9
-------
Appendix D, table 1 (continued)
IGWMC Key: 3970 Model Name: TEXASHEAT Released: 1980
Authors: E.K. Grubaugh and D.L Reddell
TEXASHEAT is a three-dimensional transient finite element model for solution of simultaneous flow and heat
transport through anisotropic, heterogeneous porous media.
Contact address: D. Reddell, Texas Water Resources Inst., Texas A&M Univ., College Station, TX
77843
IGWMC Key: 4030 Model Name: TRUMP Released: 1980
Authors: A.L Edwards, A. Rasmuson, I. Neretnicks and T.N. Narasimhan
TRUMP is a multi-dimensional model based on the integral finite difference method, to simulate coupled
steady-state or transient ground water flow and heat or solute transport in (porous) fractured rock.
Contact address: A. Rasmuson, Royal Inst. of Technology, Dept. of Chem. Eng., S-100 44 Stockholm,
Sweden
IGWMC Key: 4550 Model Name: MOTIF Released: 1986
Author: V. Guvanasen
MOTIF is a finite element model to simulate one-, two-, and three-dimensional coupled processes of
saturated or unsaturated fluid flow, conductive and convective heat transport, brine transport and single
species radionuclide transport in a compressible rock of low permeability intersected with a few major
fractures. The model includes diffusion into the rock matrix.
Contact address: Tin Chan, Atomic Energy of Canada, Ltd., Whiteshell Nuclear Research Estb.,
Pinawa, Manitoba, Canada ROE110
IGWMC Key: 4590 Model Name: MAGNUM-2D Released: 1985
Authors: R.L England, N.W. Kline, K.J. Ekblad and R.G. Baca
MAGNUM-2D is a two-dimensional, cross-sectional or three-dimensional axi-symmetric finite element model
for transient or steady-state analysis of coupled heat transfer and groundwater flow in an inhomogeneous,
anisotropic, fractured porous medium. A set of support programs are available to generate, manipulate, and
display the finite element grid; to compute and plot pathlines and traveltimes; and to plot contours, spatial
cross-sections, and time histories for temperature and hydraulic head.
Contact address: R.G. Baca. Rockwell Hartford Operations, P.O. Box 800, Richland, WA 99352
IGWMC Key: 4600 Model Name: SANGRE Released: 1986
Author: C.A. Anderson
SANGRE is a finite element code for thermomechanical analysis of two-dimensional problems in structural
geology. It allows simulation of convective heat transport, consolidation, and fluid migration. It includes
modeling capabilities for highly deformable and deformed geologic media, large deformations, faults,
overthrusts, etc. The model has a flexible, grid which can rotate and translate in time, following the
displacements of the rock matrix.
Contact address: C.A. Anderson, Los Alamos Nat. Lab., Los Alamos, NM 87545
D-1-10
-------
Appendix D, table 1 (continued)
IGWMC Key: 4610 Model Name: HST3D Released: 1991
Author: K.L Kipp, Jr.
The Heat- and Solute-Transport Program HST3D simulates ground-water flow and associated heat and
solute transport in three dimensions. The three governing equations are coupled through the interstitial pore
velocity, the dependence of the fluid density on pressure, temperature, and solute mass fraction. The
solute-transport equation is for only a single, solute species with possible linear-equilibrium sorption and
linear decay. The finite difference model handles a variety of boundary conditions for confined and
unconfined aquifer conditions including an approximate free surface. The matrix equations are solved by
either direct (Gaussian) elimination or by an iterative solver, using two-line successive overrelaxation.
Contact address: K.L. Kipp, U.S. Geol. Surv., Box 25046, Denver Fed. Ctr, Denver, CO 80225, or
Internat. Ground Water Modeling Ctr.. Col. Sch. of Mines, Golden, CO 80401.
IGWMC Key: 4700 Model Name: DSTRAM Released: 1988
Author: P.S. Huyakorn
DSTRAM is a 3-D finite-element model that simulates coupled, density-dependent single-phase fluid flow and
solute or energy transport in saturated porous media. This model can perform steady-state or transient
simulations in a cross-section, an axisymmetric configuration, or a fully-3D model. The contaminant
transport equation includes advection, hydrodynamic dispersion, linear equilibrium adsorption, and first-order
degradation. For heat transport simulation, additional processes of heat conduction and storage in the fluid
and rock matrix can also be included. Nonlinearity resulting from density differences is handled via a Picard
algorithm. The transport equation is solved using upstream weighted residual. A mesh generator is available.
Contact address: HydroGeologic, Inc., 1165 Herndon Parkway, Suite 100, Herndon, VA 22070
IGWMC Key: 5018 Model Name: AQUA Released: 1992
Authors: S.P. Kjaran, D. Egilson and S. Th. Sigurdson
AQUA is a program package developed for solving steady-state and transient two-dimensional ground-water
flow and transport problems using the finite element method. The model can be applied to either confined
or unconfined aquifers allowing for heterogeneity and anisotropy of aquifer hydraulic parameters and
time-varying infiltration and pumping. Processes included in the simulation of transport of heat and
dissolved chemicals are convection, decay, adsorption and velocity dependent dispersion. For heat
transport conduction is included. The AQUA package includes various graphic pre- and post processors
facilitating interactive grid design and data entry for areal and cross-sectional problems.
Contact address: S.P. Kjaran, Vatnaskil Consulting Engineers, Armuli 11, IS-108 Reykjavik, Iceland
IGWMC Key: 5027 Model name: DIFFMOD Released: 1987
Authors: R.W. Healy, A.L Ishii and R.G. Striegl
DIFFMOD is a modular computer code for the numerical solution of the linear diffusion equation (Pick's law)
in one or two dimensions in Cartesian or cylindrical coordinates. Applications of this generalized code
include molecular diffusion, heat conduction, and fluid flow in confined anisotropic, heterogeneous
groundwater systems. The model is based on finite difference approximations of the governing equations
and a preconditioned conjugate gradient method to solve the resulting set of algebraic equations.
Contact address: U.S. Geol. Survey, District Office, 4th floor, 102 East Main Str., Urbana, IL 61801
D-1-11
-------
Appendix D, table 1 (continued)
IGWMC Key: 5031 Model Name: CTSPAC Released: 1988
Authors: F.T. Lindstrom, D.E. Cawlfield and L Boersma
CTSPAC is an one-dimensional numerical model that couples the flow of water and the transport of heat and
solutes in layered soils with the uptake and transport of water and solutes in plants. Initial root distribution
is specified. The rate of uptake is a function of the environmental conditions that determine the plant's
transpiration rate. Water transport in the plant is based on water potential and pressure gradients according
to Munch pressure flow hypothesis. The model was developed for assessing risks involved in the use of
xenobiotic chemicals. It allows an evaluation of the rate of uptake of such chemicals from the soil solution
and the accumulation in the various plant parts.
Contact address: L. Boersma, Dept. of Soil Science, Oregon State University, Corvallis, OR 97331
IGWMC Key: 5213 Model Name: TDFD1O Released: -
Authors: L.S. Slotta
TDFD10 is a two-dimensional model for simultaneous simulation of movement of moisture, transport of heat,
and transport and fate of a contaminant in a shallow unconfined aquifer. The porous medium may be
heterogeneous. The coupled system of non-linear unsaturated/saturated moisture flow and heat and
chemical transport are solved using a finite difference approximation. The porous medium is partitioned in
three fractions: sand, clay, and organic material, with for each fraction first-order sorption kinetics included.
Time integration is performed using the backward Euler method. Dynamic boundary conditions at the
air-porous medium interface are included. A variety of first- and second-type boundary conditions are
included.
Contact address: Slotta Engineering Associates, Inc., P.O. Box 1376, Corvallis, OR 97339
IGWMC Key: 6602 Model Name: ICE-1 Released: 1989
Author: A.I. El-Kadi
ICE-1 is a one-dimensional analytical solution for the analysis of heat, solute, and water transport in
unsaturated, partially frozen soils. The program runs interactively and includes graphical representation of
results.
Contact address: A.I. El-Kadi, Dept. of Geology & Geophysics, Univ. of Hawaii-Manoa, Honolulu, HI
96822, or Intern. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO
80401.
D-1-12
-------
Appendix 0: Heat Transport, Part 2: Usability and Reliability
IGWMC
Key
100
160
513
581
582
588
612
696
697
730
2034
2070
2580
2581
2582
2620
2760
2761
2830
2860
Model
PT/CCC
SCHAFF
GAFETTA
FTRANS
GREASE
SEFTRAN
HOTWTR
BORHOL
SWENT
GEOTHER
SHALT
CFEST
SHAFT
MULKOM
TOUGH
MARIAH
MUSHRM
CHARGR
GWTHERM
UWIS-2D-
TRANSPORT
Usability
Preprocessor
N
N
N
N
U
Y
U
N
U
N
N
Y
U
U
U
U
U
U
U
N
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N
N
N
N
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N
N
Y
U
U
u
u
u
u
u
N
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Hardware Dependency
N
N
N
N
N
Y
N
N
N
N
N
N
N
N
N
U
U
U
U
U
Support
L
U
U
N
N
N
L
U
L
L
U
L
L
L
L
U
U
U
U
U
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
Y
Peer Reviewed Coding
U
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
Verified
L
L
L
L
L
E
L
L
E
L
L
E
L
L
L
L
L
L
U
U
•a
1
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I
L
U
U
L
L
L
U
U
L
L
U
L
U
U
U
u
u
u
u
u
Model Users
F
F
U
F
F
M
F
U
M
M
F
M
F
F
F
F
U
U
U
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
D-2-1
-------
Appendix D, part 2 (continued)
IGWMC
Key
2950
3083
3084
3232
3233
3234
3235
3236
3238
3375
3590
3790
3830
3840
3841
3842
3860
Model
TRANS
ROCMAS-THM
CHNTRNS
FRACFLOW
PORFLOW-II
VADOSE
FLOTRA
PORFREEZE
PORFLOW-3D
MATTUM
SPLASHWATER
PORFLO
SUTRA
SWIFT
SWIFT II
SWIFT HI/386
DFT/C-1D
Usability
Preprocessor
N
U
U
Y
Y
Y
Y
Y
Y
N
N
Y
Y
N
U
Y
U
5
(0
(0
s
0
a
8
a.
N
U
U
Y
Y
Y
Y
Y
Y
N
N
Y
Y
N
U
Y
U
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
U
U
U
Y
Y
Y
Y
Y
Y
N
N
Y
Y
N
N
Y
U
5
a
a
W
U
u
u
L
L
L
L
L
L
U
N
L
Y
N
N
L
U
Reliability
Peer Reviewed Theory
U
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
Y
Y
U
U
U
U
U
U
Y
U
U
U
U
U
Verified
U
L
L
L
E
L
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E
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1
5
U
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M
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F
M
U
U
M
M
M
M
M
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
D-2-2
-------
Appendix D, part 2 (continued)
IGWMC
Key
3861
3890
3970
4030
4550
4590
4600
4610
4700
5018
5027
5031
5213
6602
Model
FIELD-2D
PT
TEXASHEAT
TRUMP
MOTIF
MAGNUM-2D
SANGRE
HST3D
DSTRAM
AQUA
DIFFMOD
CTSPAC
TDFD10
ICE-1
Usability
5
10
U>
0
U
o
a
S
a.
N
N
N
N
N
N
N
Y
U
Y
U
U
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Y
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(0
to
O
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8
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N
N
N
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Y
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01
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a
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D-2-3
-------
Appendix E: Gas Flow and Vapor Transport, Part 1: Model Description
IGWMC Key: 5180 Model Name: MOFAT Released: 1990
Authors: Kaluarachchi, J.J , Parker, J.C.
MOFAT is an upstream-weighted finite element model to simulate coupled flow of water, nonaqueous phase
liquid (NAPL) and air, and multicomponent transport of up to five non-inert species in a two-dimensional
vertical section through saturated and unsaturated zones in Cartesian or radial coordinates. The flow
module can be used to simulate 2- or 3-phase system with gas phase treated dynamically or assumed at
constant pressure. Convective-dispersive transport in water, NAPL and gas phase is analyzed assuming
local equilibrium partitioning among phases and with the solid phase. MOFAT comes with pre- and
post-processing capabilities. Only rectangular elements with sides parallel to the principle flow axes are
permitted.
Contact Address: Environm. Systems and Technologies, Inc., P.O. Box 10457, Blacksburg, VA 24062
IGWMC Key: 5182 Model Name: VENTING Released: 1990
Authors: P.C. Johnson, M.W. Kemblowski, and J.D. Colthart (Shell Development, Houston, Texas)
VENTING is a practical program which consists of two semi-analytical models used as screening tools in
determining viability of in-situ soil venting at a given soil site. The two-dimensional (radial gas flow) models
are an equilibrium-based venting model and a vapor-phase diffusion-limited model. Ideal gas behavior is
assumed and no chemical/biological degradation is considered. They have been used to illustrate that the
three factors that most significantly influence the performance of a venting operation are: vapor flow rate;
contaminant composition; and vapor flow path relative to the contaminant location. They relate the applied
vacuum, soil permeability, and spill composition to the vapor flow rates, velocities, mass removal rates, and
residual composition changes with time.
Contact Address: Environm. Systems and Technologies, Inc., P.O. Box 10457, Blacksburg, VA 24062
IGWMC Key: 5185 Model Name: MOTRANS Released: 1992
Authors: Katyal, A.K., Parker, J.C.
MOTRANS is a 2-dimensional vertical section or radially symmetric upstream-weighted finite element
program for flow of air, light or dense organic liquid and water, and coupled transport of up to 5 partionable
species. The program, which uses linear rectangular elements, allows inclusion or elimination of flow
equations for selected phases to achieve maximum flexibility and efficiency. Soil hydraulic properties are
described by the multi-phase van Genuchten model with NAPL entrapment. The nonlinearity in the
equations is handled by Newton-Raphson iteration. Multispecies transport is simulated assuming local
equilibrium or kinetically controlled interphase mass transfer. Pre- and postprocessing modules are
available.
Contact Address: Environm. Systems and Technologies, Inc., P.O. Box 10457, Blacksburg, VA 24062
IGWMC Key: 5390 Model Name: CSUGAS Released: 1991
Authors: G.P. Sabadell, J.J. Eisenbeis, and O.K. Sunada
A finite-difference model for simulating one-, two-, or three-dimensional compressible gas flow in a porous
medium. It can model steady-state and transient conditions and computes soil gas pressure distribution
due to hydrologic or artificial influence.
Contact address: O.K. Sunada, Dept. Civil Eng., Colorado State Univ., Fort Collins, CO 80523.
E-1-1
-------
Appendix E, table 1 (continued)
IGWMC Key: 5400 Model Name: - Released: 1991
Author: Jong Soo Cho
A steady-state model based on point-source, line source, point dipole, line dipole and panel dipole solutions
of the soil air pressure distribution equation. The model can handle various boundary conditions by
superposition of the line and panel dipoles on the boundaries.
Contact address: Jong Soo Cho, U.S. EPA, R.S. Kerr Env. Res. Lab, Ada, OK 74820.
IGWMC Key: 5401 Model Name: - Released: 1991
Author: Jong Soo Cho
Based on a finite difference solution of the three-dimensional steady-state soil air flow and transient
contaminant transport equations together with a mass balance equation for residual hydrocarbon inside soil
matrices. Includes interfacial mass transfer between air and residual hydrocarbon contacting the air. The
air flow equations are solved with a point Jacob! iterative method; an explicit method is used to solve the
convective diffusion equations.
Contact address: Jong Soo Cho, U.S. EPA, R.S. Kerr Env. Res. Lab, Ada, OK 74820
IGWMC Key: 5410 Model Name: -- Released: 1987
Authors: D.E. Metcalfe and G.J. Farquhar
A finite-element model for simulation of two-dimensional gas migration through the unsaturated zone. It
includes advection and transient gas phase flow. The model accounts for gas migration due to gas
pressure, concentration (diffusion), and velocity gradients. It is based on the continuum approach presented
by Bear (1972) for contaminant transport in groundwater. This research model successfully reproduced
observed gas pressure and concentration data at landfill sites.
Contact address: CANVIRO Consultants, Ltd., 178 Loisa Str, Kitchener, Ontario, Canada N2H 5M5.
IGWMC Key: 5411 Model Name: - Released: 1980
Authors: M.F.N. Mohsen, G.J. Farquhar, and N. Kouwen
A finite-element model for transient simulation of three-dimensional (axisymmetric) gas migration through
various soil strata. The model uses quadratic triangular elements to solve the diffusion-convection equation
of a binary mixture of gases. It handles soil stratification with varying properties, inhomogeneous fluid, a
combination of Dirichlet, Neumann, and flux type boundary conditions, and time-varying boundary
conditions. This research model compares favorably with an analytical solution of the diffusion-convection
equation for simple situations and with observed field measurements.
Contact address: G.J. Farquhar, Dept. of Civil Eng., Univ. of Waterloo, Waterloo, Ontario, Canada
N2L3G1.
E-1-2
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 3432 Model Name: CXTFIT Released: 1985
Authors: Parker, J.C., M.Th. Van Genuchten
The purpose of CXTFIT is to determine values for one-dimensional analytical solute transport parameters
using a nonlinear least-squares inversion method. The analytical model includes advection, dispersion,
diffusion, first-order decay and zero-order production.
Contact Address: J.C. Parker, Virginia Polytechnical Institute, Dept. Soil & Environmental Science,
Blacksburg, VA 24061; or Internal. Ground Water Modeling Ctr., Colorado Sch. of
Mines, Golden, CO 80401.
IGWMC Key: 3450/3451 Model Name: DISPEQ/DISPER/PISTON Released: 1983
Authors: Fluhler, H., and W.A. Jury
DISPEQ/DISPER/PISTON is a series of three finite difference research models to simulate one-dimensional
transport of reactive solute species through soil columns, including dispersion, instantaneous equilibrium
adsorption (DISPEQ) and rate dependent adsorption (DISPER). PISTON is based on piston type flow
without dispersion.
Contact Address: H.U. Fluhler, 240 Nick Davis Road, Madison, AL 35758
IGWMC Key: 3540 Model Name: CREAMS Released: 1982
Author: Knisel, W.G.
CREAMS (A field scale model for Chemicals, Runoff, and Erosion from Agricultural Management Systems)
is a general watershed model designed to evaluate non-point source pollution from alternate management
practices for field-size areas. It consists of three main components: hydrology, erosion/sedimentation and
chemistry. The hydrology model handles storm runoff, infiltration, soil water movement (providing amount
of seepage beneath root zone and initial soil water content before a storm), and soil/plant evapotranspiration
between storms. The chemistry model includes a nutrient (nitrogen and phosphorus) submodel and a
pesticide submodel. CREAMS was developed for evaluation of agricultural management systems and their
effects on non-point pollution potential. CREAMS is the predecessor of GLEAMS,
Contact Address: W.G. Knisel, USDA Agricultural Research Service, Southeast Watershed Research
Laboratory, P.O. Box 946, Tifton, GA 31793
IGWMC Key: 3541 Model Name: GLEAMS Released: 1990
Authors: Leonard, R.A., W.G. Knisel, and F.M. Davis
GLEAMS (Groundwater Loading Effects on Agricultural Management Systems) was developed as an
extension of an earlier USDA model, CREAMS. Both models simulate soil water balance and surface
transport of sediments and chemicals from agricultural field management units. GLEAMS, in addition,
simulates chemical transport in and through the plant root zone. Several other features were added such
as irrigation/chemigation options, pesticide metabolite tracking, and software to facilitate model
implementation and output data analysis. Input requirements for the model include daily rainfall volumes,
crop and management parameters; soil and physical parameters; pesticide property data such as solubility,
and expected half-life in soil and/or foliage.
Contact Address: USDA-ARS, P.O. Box 946, Tifton, GA 31793
C.4-1-3
-------
Appendix C.4, part 1 (continued)
IGWMC Key: 3830 Model Name: SUTRA Released: 1990
Author: Voss, C.I.
SUTRA (Saturated-Unsaturated TRAnsport) simulates transient or steady-state, two-dimensional, variably
saturated, fluid density dependent ground water flow with transport of energy or chemically reactive species
solute transport. The model employs a hybrid finite-element and integrated-finite-difference method to
approximate the coupled equations. Solute transport include advection, dispersion, diffusion, equilibrium
adsorption on the porous matrix, and both first-order and zero-order decay or production. Energy transport
may take place in both the solid matrix and the liquid phase. SUTRA may be employed in both areal
(horizontal) and cross-sectional mode for saturated systems or in cross-sectional mode only for unsaturated
systems.
SUTRA provides, as preliminary calculated results, fluid pressures and either solute concentrations or
temperatures. Mesh construction is flexible for arbitrary geometries employing quadrilateral finite elements
in Cartesian or radial-cylindrical coordinates. The mesh might be coarsened through the use of pinch
nodes. Boundary conditions, sources and sinks may be time dependent. The model has a rest art option.
Options are also available to print fluid velocities, and fluid mass, and solute mass or energy budgets for
the system. SUTRA's numerical algorithms are not specifically applicable to non-linearities of unsaturated
flow. Therefor SUTRA, as distributed by the USGS, requires fine spatial and temporal discretization for
unsaturated flow. The user can replace the included function for unsaturated flow by others, and recompile
the code.
Contact Address: Voss, C.I., U.S. Geological Survey, 431 National Center, Reston, VA 22092;
Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401;
or Scientific Software, Washington, D.C.
IGWMC Key: 4081 Model Name: TRIPM Released: 1983
Author: Gureghian, A.B.
TRIPM is a two-dimensional finite element model to predict the transport of radionuclides decay chain into
and in a phreatic aquifer. It simulates the simultaneous cross-sectional flow water and the transport of
reacting solutes through saturated and unsaturated porous media. The influence of soil-water pH on the
distribution coefficient is included. Boundary conditions include seepage faces.
Contact Address: Performance Assessment Dept., Office of Nuclear Waste Isolation, Battelle Project
Management Division, 505 King Avenue, Columbus, OH 43201
IGWMC Key: 4140 Model Name: MLSOIL/DFSOIL Released: 1984
Authors: Sjoreen, A.L, D.C. Kocher, G.G. Killough, and C.W. Miller.
MLSOIL (Multi-Layer SOIL model) calculates an effective ground surface concentration to be used in
computations of external doses. The program implements a five compartment linear-transfer model to
calculate the concentrations of radionuclides in the soil following deposition on the ground surface from the
atmosphere. The model considers leaching through the soil as well as radioactive decay and buildup.
DFSOIL calculates the dose in air per unit concentration at 1 m above the ground from each of the five soil
layers used in MLSOIL and the dose per unit concentration from an infinite plane source. MLSOIL and
DFSOIL are part of the Computerized Radiological Risk Investigation System (CRRIS).
Contact Address: A.L. Sjoreen, Oak Ridge Nat. Lab., Health and Safety Research Div., Oak Ridge,
Tennessee 37831
C.4-1-4
-------
Appendix E, table 1 (continued)
MAGICS - continued
curbs numerical oscillations. Direct banded matrix solvers are used to solve the matrix systems of 2-D
problems. A block-iterative ORTHOMIN solver is used to solve 3-D problems. All boundary conditions can
be chosen constant in time or variable in time with either continuous or stepwise changes. MAGICS has
been verified for a variety of problems by comparison of its numerical solutions with available analytical
solutions and documented numerical results from several other codes including HYDRUS, VAM2D, VAM3D,
SWANFLOW, and NAPL3D. MAGICS is a robust code designed to solve highly nonlinear field problems
involving large contrasts in soil properties and highly nonlinear situations involving sharp saturation fronts,
and to provide accurate mass balance calculations.
Contact address: HydroGeologic, Inc., 1165 Herndon Parkway, suite 900, Herndon, VA 22070
IGWMC Key: 5940 Model Name: HYPERVENTILATE Released: 1992
Author: Johnson, P.
HYPERVENTILATE is an user-friendly vapor flow screening model for feasibility studies. It operates as a
decision tree for investigating the potential implementation of soil-vapor extraction at a site. The program
is based on the use of hypercard/hypertext using multiple card files, addressing such topics as air
permeability testing, aquifer characterization and system design. It requires the following input: flow rate, site
dimension, porosity, temperature, sorption isotherms, boiling point data on spill components. It estimates
flow rates, removal rates, residual concentrations, and the number of wells required.
Contact address: Johnson, P., Shell Development, Westhollow Research Center, Houston, Texas
IGWMC Key: 5950 Model Name: SVE COLUMN Released: 1991
Author: Wilson, D.J.
SVE Column is a model for simulation of soil vapor stripping, either for use as a lab column model using
experimental data to obtain the effective Henry's constant, or as a filed model assuming axial symmetry.
The models are used to examine the effects of well depth, well spacing, the use of impermeable caps,
passive vent wells, soil pneumatic permeability, and recontamination from underlying NAPL. The models
are either solved analytically, or using an over-relaxation finite difference technique.
Contact address: Wilson, D.J., Vanderbilt Univ., Dept. of Chemistry, Box 1822, Sta. B., Nashville, TN
37235.
IGWMC Key: 6605 Model Name: AIR Released: 1990
Authors: C. Lin and W. Kinzelbach
A user-friendly PC implementation of a three-dimensional finite difference model of one-phase, steady-state
gas flow in the unsaturated zone. It facilitates alternatively the computation of compressible or
incompressible gas flow. The model assumes that the soil moisture distribution is constant in time and that
the free ground-water surface is an impervious boundary for gas and its location known and fixed in space.
The finite difference equations are solved using a preconditioned conjugate gradient method. Pathlines are
computed using particle tracking in the velocity field and Euler integration. The software includes graphic
display of results.
Contact address: W. Kinzelbach, Gesamthochschule Kassel-Universitat, FB-14, D-3500 Kassel,
Germany.
E-1-5
-------
Appendix E: Gas Flow and Vapor Transport, Part 2: Usability and Reliability
IGWMC
Key
5180
5182
5185
5390
5400
5401
5410
5411
5420
5430
5440
5441
5450
5490
5821
5940
5950
6605
Model
MOFAT
VENTING
MOTRANS
CSUGAS
—
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PETROS
MAGICS
HYPER-
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SVE COLUMN
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Usability
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Y
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Y
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Note: Most codes listed are research codes and not designed as general-use codes. Most of the general-use codes have
user-friendly data entry and postprocessing options.
E-2-1
-------
Appendix F: Flow and Transport in Fractured Rock, Part 1: Model Description
Note: Many of the models for flow and transport in fractured rock are research codes.
IGWMC Key: 581 Model Name: FTRANS Released: 1982
Authors: Huyakorn, P.S., et al.
FTRANS (fracture Flow, Thermal and RAdioNuclide Solute transport) is a 2D finite-element model to simulate
transient, saturated single phase flow, heat transport, and chemical or radionuclide transport in fractured or
unfractured, anisotropic, heterogeneous, confined or semi-confined multilayered porous media. For any type
of fractured system, the flow and transport analysis are performed taking into account interaction between
the porous matrix and the fractures. The analyses are made in the main areal flow plane, in a vertical
cross-section, or in an axisymmetric configuration. The code fully accounts for fluid leakages, advection,
dispersion, sorption, first-order decay, chain reactions, and solute diffusion and heat conduction in the
porous matrix, coupled thermal fluid capability and density-dependent flow and solute transport.
Contact Address: Performance Assessment Dept, Office of Nuclear Waste Isolation, Battelle Project
Management Division, 505 King Avenue Columbus, Ohio 43201
IGWMC Key: 582 Model Name: GREASE Released: 1982
Author: Huyakorn, P.S., et al.
GREASE 2 is a multi-purpose finite element model to simulate transient, multi-dimensional, saturated
groundwaterflow, solute and/or energy transport in fractured and non-fractured, anisotropic, heterogeneous,
multilayered porous media. The analysis can be performed for confined, semiconfined, or unconfined
groundwater reservoir systems. Fluid leakage or heat transfer between the aquifer and its confining layer
can be taken into account. The model allows for analysis of areal flow, vertical cross-sectional flow or flow
in an axisymmetric configuration. Coupled thermal fluid flow capability, and density dependent flow and
solute transport capability area also available. Sorption and decay can be included in the solute transport
analysis.
Contact Address: GeoTrans, Inc., 46050 Manekin Pla2a, Suite 100, Sterling, VA 22170
IGWMC Key: 584 Model Name: STAFAN Released: 1982
Author: Huyakorn, P.S., et al.
STAFAN (STress And Flow ANalysis) is a two-dimensional finite element model for simulation of transient
fluid flow and the interaction of fluid pressure and mechanical stresses in deformable fractured and
unfractured porous media. The model takes into account the flow behavior of a deformable fractured
system with fracture-porous matrix interactions, the coupling effects of fluid pressure and mechanical
stresses in a medium containing discrete joints, and inelastic response of the individual joints of the rock
mass subject to the combined fluid pressure and mechanical loading.
Contact Address: Office of Nuclear Waste Isolation, Battelle Project Management Division, 505 King
Avenue, Columbus, Ohio 43201
F-1-1
-------
Appendix F, part 1 (continued)
IGWMC Key: 588 Model Name: SEFTRAN Released: 1986
Authors: Huyakorn, P.S., Ward, D.S.3, Rumbaugh, J.O., Broome, R.W.
SEFTRAN (Simple and Efficient Flow and TRANsport model) is a concise finite element model to simulate
transient two-dimensional fluid flow and transport of non-conservative contaminants or heat in isotropic,
heterogeneous aquifers. It can solve the flow and transport equations in an areal plane, a vertical
cross-section, or an axisymmetric configuration. Line elements may be used to simulate discrete fractures
or rivers.
Contact Address GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 589 Model Name: TRAFRAP Released: 1987
Authors: Huyakorn, P.S., White, Jr., H.O., Guvanasen, V.M., Lester, B.H.
TRAFRAP-WT is a two dimensional finite element code which simulates transient groundwater flow and
transport of a non-conservative contaminant or a radionuclide in fractured or unfractured porous media.
Fracture systems may be modeled using either the dual porosity approach or the discrete fracture approach.
TRAFRAP-WT can be used for both confined and unconfined aquifer systems. Model processes include fluid
interactions between fractures and porous matrix blocks, advective-dispersive transport in fractures and
diffusion in the porous matrix blocks, and chain reactions of radionuclides.
Contact Address: Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401
IGWMC Key: 695 Model Name: NETFLO (Network Flow) Released: 1982
Authors: Pahwa, S.B., Rama Rao, B.S.
NETFLO is a finite element model to simulate steady-state saturated flow in a fractured medium by an
equivalent three-dimensional network of in-series and parallel flow members. The algorithm is based on the
application of Darcy's law along each member and conservation of mass in each node. The boundary
conditions may be either prescribed head or a sink/source at each node. The code output pressures at
each node and velocities, fluxes and travel times in each member. It also provides all possible flow paths
between a source node (e.g. a repository) and a specified discharge node, the path lengths and the
pertinent mean interstitial velocity and travel time along each path for use in a one-dimensional transport
code such as GETOUT. The nodal equations are solved using Gaussian elimination.
Contact Address: Performance Assessment Department, Office of Nuclear Waste Isolation, Battelle
Project Management Division, 505 King Avenue, Columbus, Ohio 43201
IGWMC Key: 2034 Model Name: SHALT Released: 1979
Authors: Pickens, J.F., Grisak, G.E.
SHALT is a finite element model that simulates heat and solute transport in a fractured, anisotropic,
heterogeneous, saturated or unsaturated, confined or unconfined, two-dimensional groundwater flow system.
The Galerkin finite element method uses triangular elements and a sequential solution technique. The model
simulates density dependent compressible fluid flow; heat convection, conduction and dispersion; solute
advection, dispersion and linear equilibrium adsorption; radioactive decay; ion exchange; diffusion; sorption;
and various first-order chemical reactions.
Contact Address: Pickens, J.F., Intera Technologies, Inc., 6850 Austin Center Blvd., Suite # 300,
Austin, TX 78731
F-1-2
-------
Appendix F, part 1 (continued)
IGWMC Key: 2581 Model Name: MULKOM Released: 1985
Author: Pruess, K.
MULKOM is an integrated finite difference model to simulate multi-component, multi-phase fluid and heat
flow in porous or fractured media. The model incorporates convection, change of phase, dissolution and
precipitation of silica, equilibration of noncondensible gases, transport of noncondensible gases and
dissolved solids.
Contact Address: Pruess, K.,Lawrence Berkeley Lab., Univ. of California, Berkeley, CA 94720
IGWMC Key: 2582 Model Name: TOUGH Released: 1987
Authors: Pruess, K., Tsang, Y.W., Wang, J.S.Y.
TOUGH (Transport of Unsaturated Groundwater and Heat) is a multi-dimensional integrated finite difference
model for transient simulation of the strongly coupled transport of water, air, vapor and heat transport in
fractured unsaturated porous media. The model includes convection, condensation, capillary forces,
evapotranspiration, heat conduction and diffusion, change of phase, adsorption, fluid compression,
dissolution of air in liquid, and buoyancy. The gas and liquid phase flow of air and water, and heat transport
are solved in a fully coupled manner. Time is discretized fully implicitly. The TOUGH code includes a library
of commonly used functions for the capillary pressure-relative permeability relationships (does not allow for
hysteresis). The model handles a variety of boundary conditions.
Contact Address: Pruess, K., Lawrence Berkeley Lab., Earth Science Div., Univ. of California,
Berkeley, CA 94720
IGWMC Key: 3083 Model Name: ROCMAS-THM Released: -
Authors: Noorishad, J., Witherspoon, P.A.
ROCMAS-THM is a two-dimensional research model for coupled hydraulic-thermal-mechanical analysis of
porous fractured rock.
Contact Address: Noorishad, J., Lawrence Berkeley Lab., Earth Science Div., Univ. of California,
Berkeley, CA 94720
IGWMC Key: 3232 Model Name: FRACFLOW Released: 1981
Author: Sagar, B.
FRACFLOW is an integrated finite difference model for steady and nonsteady state analysis of coupled,
density-dependent flow, heat and mass transport in fractured confined aquifers. The processes in the
porous medium are simulated in two dimensions and in the fractures in one dimension. Fractures may have
arbitrary orientations. Any number of fractures, each of different properties may be incorporated. The
program includes first-order chemical reactions. A preprocessor and a number of graphic post-processing
routines are available.
Contact Address: B. Sagar, Southwest Research Inst, P.O.Box 0510, Div. 20, San Antonio, TX 28510
F-1-3
-------
Appendix F, part 1 (continued)
IGWMC Key: 3238 Model Name: PORFLOW-3D Released: 1992
Author: Runchal, A.K.
PORFLOW-3D is an integrated finite difference model to simulate coupled transient or steady-state,
multiphase, fluid flow, and heat, salinity, or chemical species transport in variably saturated porous or
fractured, anisotropic and heterogeneous media. The program facilitates arbitrary sources or sinks in
three-dimensional cartesian or axisymmetric (cylindrical) geometry. The user interface is based on the
FREEFORM language using simple English-like commands. The software includes the ARCPLOT graphic
post processor.
Contact Address: A. Runchal, 1931 Stradella Road, Bel Air, CA 90077
IGWMC Key: 3374 Model Name: FRACPORT Released: 1985
Authors: Deangelis, D.L, Yeh, G.T., Huff, D.D.
FRACPORT (FRACtured PORous medium Transport) is an integrated compartmental model for describing
the advective-dispersive transport of a non-conservative solute in a three-dimensional fractured saturated
porous medium. The model assumes a known velocity field. It solves the transport equation on two
different time scales: one related to rapid transport of solute along fractures and the other related to slower
transport through the porous matrix. A governing equation is developed for each interior compartment.
The equation are assembled in matrix form and solved in two steps, first using a direct method or an
iterative method, followed by an iteration procedure over all boundary connectors. The model handles
Dirichlet, Neumann, Cauchy, and variable boundary conditions.
Contact Address: DeAngelis, D.L, Oak Ridge Nat. Lab., Environm. Sc. Div., Oak Ridge, TN 37830
IGWMC Key: 3790 Model Name: PORFLO Released: 1985
Authors: Runchal, A.K., Sagar, B., Baca, R.G., Wine, N.W.
PORFLO is an integrated finite difference model for transient two-dimensional or axisymmetric simulation
of coupled buoyancy driven groundwater flow, heat transfer and radionuclide transport in layered geologic
systems. Heat transfer processes include storage, advection, conduction, dispersion and heat generation.
Fluid flow processes include storage, inflows and outflows, pore pressure buildup, buoyancy driving force
and temperature dependent hydraulic conductivity. Density is a function of concentration. Mass transport
processes can handle multi-phase conditions and include storage, advection, dispersion, diffusion, sorption,
retardation, dissolution, decay, and mass release.
Contact Address: N.W. Kline, Boeing Computer Services, P.O Box 300, Richland, WA 99352
IGWMC Key: 3842 Model Name: SWIFT III/SWIFT 386 Released: 1992
Author: Ward, D.S.
SWIFTIII/386 is a transient, fully three-dimensional model which simulates the flow and transport of fluid,
heat (energy), brine, and radionuclide chains in porous and fractured geologic media. The primary
equations for fluid, heat, and brine are coupled by fluid density, fluid viscosity, and porosity. Both Cartesian
and cylindrical coordinate systems may be used. For the fracture zone the model allows both dual-porosity
and discrete fractures. Migration within the rock matrix is characterized as a one-dimensional process.
continued
F-1-4
-------
Appendix F, part 1 (continued)
SWIFT HI/386 -- continued
Aquifer hydraulic characteristics may be heterogeneous and anisotropic under confined or unconfined
conditions. The model includes linear and nonlinear (Freundlich) isothermal equilibrium adsorption,
hydrodynamic dispersion, and diffusion.
Discretization is performed by the finite-difference method using centered or backward weighing in the time
and space domains. Matrix solution is performed either by Gaussian elimination or by two-line successive
over-relaxation. SWIFT/386 incorporates a run-time monitor to display the actions and numerical behavior
of on-going transport simulations. The IBM PC version handles between 10,000 and 30,000 finite difference
blocks.
SWIFT HI/386 handles a variety of boundary conditions and source terms for both the porous and fractured
media including prescribed pressure (head), temperature, and brine concentration; prescribed flux of fluid
(water), heat, brine, or (nuclide) mass; wellbore injection/production submodel subject to pumping
constraints; aquifer influence function (i.e. Carter-Tracy infinite reservoir); waste leach radionuclide submodel
for waste repository nuclides and heat; and free (phreatic) surface with recharge.
SWIFT IN/SWIFT 386 is an extension of SWIFT II (IGWMC Key # 3842), which in turn is an update and
extension of SWIFT (Sandia Waste-Isolation Flow and Transport; IGWMC Key # 3841), released in 1981.
Originally, refinements in user options, mapping facilities and auxiliary files were included. A postprocessing
program UNSWIFT allows direct interfacing with the SURFER contouring package.
Contact Address: D.S. Ward. GeoTrans, Inc., 46050 Manekin Plaza, Suite 100, Sterling, VA 22170
IGWMC Key: 4031 Model Name: TRUCHN/ZONE Released: 1984
Authors: Rasmuson, A., Neretnieks, I.
TRUCHN/ZONE is an integrated finite difference model for simulation of advective-dispersive transport of
radionuclides in strongly fissured zones including diffusion into the rock matrix. The model may handle
instantaneous sorption in a portion of the rock (surface sorption) and sorption on the micropore surface.
The prescribed water velocity may vary strongly along a flow path, especially if the flow paths enters a
strongly fissured zone. The model, which uses an axi-symmetric coordinate system, can handle varying
matrix block sizes and shapes using an improved MING concept (Multiple INter-acting Continua).
Contact Address: Rasmuson, A., Royal Institute of Technology, Department of Chemical Engineering,
S-100 44 Stockholm, Sweden
IGWMC Key: 4270 Model Name: TRACR3D Released: 1984
Author: Travis, B.J.
TRACR3D is a three-dimensional implicit (for flow)/semi-implicit (for transport) finite difference model for
simulation of transient two-phase flow of water and air and of non-conservative multi-component transport
in deformable, heterogeneous, water-saturated or variably-saturated, reactive porous and/or fractured media.
Transport processes include advection, dispersion, sorption, and decay. The code has been applied to
study the hydrology and transport of colloids with radioactive materials at a low-level radioactive waste
disposal site.
Contact Address: Travis, B.J., Los Alamos Nat. Lab., Los Alamos, NM 87545
F-1-5
-------
Appendix F, part 1 (continued)
IGWMC Key: 4470 Model Name: FRACTEST Released: 1986
Author: Karasaki, K.
FRACTEST simulates three-dimensional flow in unconfined non-porous rock with discrete fractures. The
model has been developed to support well test analysis in fractured systems. The model includes a mesh
generator to produce a representative fracture system, and a finite element simulator for calculation of
transient hydraulic heads using a parallel processor.
Contact Address: Lawrence Berkeley Lab., Earth Sc. Div., Univ. of Calif., Berkeley, CA 94720
IGWMC Key: 4550 Model Name: MOTIF released: 1984
Authors: Guvanasen, V.
MOTIF (Model of Transport in Fractured/Porous Media) is a finite element model to simulate one-, two-,
and three-dimensional coupled processes of saturated or unsaturated fluid flow, conductive and convective
heat transport, brine transport and single species radionuclide transport in a compressible rock of low
permeability intersected with a few major fractures. The model includes diffusion into the rock matrix.
Contact Address: T. Chan, Atomic Energy of Canada, Ltd., Whiteshell Nuclear Research Estb.,
Pinawa, Manitoba, Canada ROE110
IGWMC Key: 4590 Model Name: MAGNUM-2D Released: 1985
Authors: England, R.L, Wine, N.W., Ektrfad, K.J., Baca, R.G.
MAGNUM-2D is a two-dimensional, cross-sectional or three-dimensional axi-symmetric finite element model
for transient or steady-state analysis of coupled heat transfer and groundwater flow in an inhomogeneous,
anisotropic, fractured porous medium. Transport processes include advection, dispersion, diffusion, sorption
and decay for multiple species. A set of support programs are available to generate, manipulate, and
display the finite element grid; to compute and plot pathlines and traveltimes; and to plot contours, spatial
cross-sections, and time histories for temperature and hydraulic head. The program can be linked with a
radionuclide-chain transport code CHAINT (IGWMC Key 3791).
Contact Address: Rockwell Hanford Operations, P.O. Box 800, Richland, WA 99352
IGWMC Key: 4600 Model Name: SANGRE Released: 1986
Author: Anderson, C.A.
SANGRE is a finite element code for thermomechanical analysis of two-dimensional problems in structural
geology. It allows simulation of convective heat transport, consolidation, and fluid migration. It includes
modeling capabilities for highly deformable and deformed geologic media, large deformations, faults,
overthrusts, etc. The model has a flexible, grid which can rotate and translate in time, following the
displacements of the rock matrix.
Contact Address: C.A. Anderson, Los Alamos Nat. Lab., Los Alamos, NM 87545
F-1-6
-------
Appendix F, part 1 (continued)
IGWMC Key: 4710 Model Name: STAFF2D Released: 1988
Authors: Huyakorn, P.S., et al.
STAFF2D (Solute Transport And Fracture Flow in 2 Dimensions) is a 2 dimensional finite element model that
simulates groundwater flow and solute transport in fractured or granular porous media under confined or
unconfined conditions. The code performs steady-state and transient simulations in a cross-section, an areal
plane, or an axisymmetric configuration. Contaminant transport accounts for advection, dispersion, linear
equilibrium sorption and first-order degradation. Fractured porous media are represented using discrete
fracture and dual porosity approaches. Spatial discretization is performed using a combination of linear and
rectangular elements. The transport equation is solved using upstream weighing. STAFF2D also provides
an option to use orthogonal curvilinear elements for single or double well analysis.
Contact Address: Hydrogeologic, Inc., 1165 Herndon Parkway, #900, Herndon, VA 22070
IGWMC Key: 5003 Model Name: MLU Released: 1986
Author: Hemker, C.J.
MLU (Multi-Layer Unsteady-state model) is a program for drawdown calculations and inverse modeling
(aquifer tests) of transient flow in layered (up to 9 aquifers) and fissured (double porosity aquifer systems
of (semi-)confined and unconfined conditions. The model is based on a series of analytical solutions.
Contact Address: Hemker, C.J., Elandsgracht 83, 1016TR Amsterdam, The Netherlands
IGWMC Key: 5022 Model Name: 3-D FE DUAL POROSITY FLOW AND TRANSPORT MODEL
Author: Glover, K.C. Released: 1987
This model simulates three-dimensional groundwater flow and advective-dispersive solute transport in oil
shale and associated hydrogeologic units. The model treats oil shale as a dual porosity medium by
simulating flow and transport in parallel fractures separated by a matrix (blocks) of high porosity, low
permeability material using the upstream finite element method. Diffusion of the solute between fractures
and the essentially static water of the shale matrix is simulated including an analytical solution that acts as
a source-sink term to the differential equation of solute transport. The resulting equations are solved using
a Gauss elimination scheme.
Contact Address: U.S. Geological Survey, P.O. Box 1125, Cheyenne, WY 82003
IGWMC Key: 5025 Model Name: NEFTRAN/NWFT/DVM Released: 1987
Authors: Longsine, D.E., Bonano, E.J., Harlan, C.P.
NEFTRAN (NEtwork Flow and TRANsport) is a discrete finite difference model for groundwater flow and
radionuclide transport in high-level radioactive waste repositories in deep saturated and fractured basalt
formations. It handles a generalized flow network, matrix diffusion, leg transfer, mixing cell and multiple
radionuclide decay chains. The underlying assumption is that all significant flow and radionuclide transport
take place along one-dimensional discrete 'legs' or paths. These legs are assembled into a
multi-dimensional network. A particle tracking model is used to define the trajectory a particle follows from
a given point until it crosses a boundary. The resulting information is used to construct the network and
define the boundary conditions.
Contact Address: Sandia National Laboratories, Albuquerque, New Mexico 87185
F-1-7
-------
Appendix F, part 1 (continued)
IGWMC Key: 5320 Model Name: 3D FRACTURE GENERATOR Released: 1984
Authors: Huang, C., Evans, D.D.
This code is based on a 3-dimensional fracture generating scheme which can be used to simulate water flow
and contaminant transport through fractured rock. It is limited to saturated conditions, zero rock matrix
permeability, and steady state flow. The scheme creates finite planar plates of uniform thickness which
represent fractures in 3-dimensional space. A given fracture is defined by its center location, orientation,
shape, areal extent, and aperture. Individual fractures are generated to form an assemblage of a certain
fracture density. Flow through the fractures is two-dimensional and laminar and is described by Poiseuille's
law. The flow solution provides head, velocities, fluxes, and traveltimes. Transport is advective and
piston-type, solved explicitly.
Contact Address: D.D. Evans, Dept. of Hydrology and Water Resources, University of Arizona,
Tuscon, AZ 85721
IGWMC Key: 5640 Model Name: NETFLO/NETRANS Released: 1988
Author: Rouleau, A.
This stochastic discrete fracture (SDF) modeling package simulates groundwater flow and mass transport
in fracture systems. It contains 4 programs: (1) NETWRK generates two-dimensional fracture networks using
a monte carlo method based on the statistics of field data on fracture geometry; (2) APEGEN generates
supplementary aperture distributions; (3) the NETFLO finite element code computes the steady-state fluid
flow through the fracture network generated by NETWRK and APEGEN, and computes the statistics of
selected parameters in every ten-degree range of direction, including the total length of fracture segments,
total flow velocity, and total flow rate; and (4) NETRANS computes the transit time of particles over an
arbitrary distance using a second-level stochastic process.
Contact Address: Rouleau, A., Dept. de Sciences Appliquees, Universite du Quebec a Chitoutimi, 555
Boulevard de I'Universite, Chicoutimi, Quebec G7H 2B1, Canada
IGWMC Key: 5660 Model Name: FLASH Released: 1992
Authors: Baca, R.G., Magnuson, S.O.
FLASH is a finite element model for simulation of two-dimensional, cross-sectional, variably saturated fluid
flow in fractured porous media at an arid site, together with two-dimensional, horizontal, saturated flow in
an underlying unconfined aquifer. In addition, the code has the capability to simulate heat conduction in
the vadose zone. The Richard's equation for variably saturated flow is solved iteratively using a Picard or
Newton iteration technique, the unconfined flow equation is solved using Newton-Raphson iteration. The
variably saturated module handles 1st, 2nd and 3rd type b.c.'s, the saturated module only 1st and 2nd type
b.c.'s. The FLASH code can be interfaced with the FLAME code to simulate contaminant transport in the
subsurface.
Contact Address: Baca, R.G., Idaho National Eng. Lab., Subsurface and Environm. Modeling Unit,
Geoscience Group, EG&G, Inc, P.O. Box 1625, Idaho Falls, Idaho 83415.
F-1-8
-------
Appendix F, part 1 (continued)
IGWMC Key: 5980 Model Name: FRANET Released: 1987
Authors: Kanehiro, B.Y., Lai, C.H., Stow, S.H.
The discrete fracture code FRANET is based on a Galerkin finite element formulation for steady state and
transient fluid flow in an arbitrary fracture network. It considers isothermal flow of a slightly compressible
fluid in the laminar regime and assumes that fracture aperture or equivalent fracture hydraulic conductivity
is a function of fluid pressure. The model solves the governing equation for fluid flow in a local
one-dimensional coordinate system for each fracture of the network subject to the continuity of hydraulic
head at fracture intersections. The model might be coupled with a fracture network mesh generator
representing the statistical distribution of the fracture parameters.
Contact Address: Kanehiro, B.Y., Berkeley Hydrotechnique, Inc., 2030 Addison St., Suite 500,
Berkeley, CA 94704
IGWMC key: 6660 Model Name: CRACK Released: 1988
Author: Sudicky, E.A.
The CRACK microcomputer software package contains four analytical models for mass transport in fractured
porous media. The following models are included: transport in a single fracture including matrix diffusion
with and without dispersion along fracture axis (models CRACKD and CRACKDO, respectively); transport
in a system of parallel fractures including matrix diffusion with no dispersion along fracture axis (PCRACKO);
and transport in a single fracture with matrix diffusion and radial diverging flow (RCRACK). The package
includes a plotting routine for concentration vs. time at different locations or concentration vs. position for
different times (PLOTC).
Contact Address: Waterloo Centre for Groundwater Research, Dept. of Earth Sciences, University of
Waterloo, Waterloo, Ontario N21 3G1, Canada
IGWMC Key: 6810 Model Name: BIM/BIM2D/BIM3D/FRACGEN Released: 1989
Authors: Rasmussen, T.C., Evans, D.D.
BIM/FRACGEN is simulates flow and (advective)solute transport in unsaturated, fractured, porous or
non-porous media. It solves the boundary value problem within intersecting fracture planes using the
boundary integral method applied to two and three-dimensional formulations for flow using a constant
capillary head within individual fractures. The transport problem is solved through calculating travel times
and breakthrough curves by integrating the inverse velocity over a streamline, and then summing over all
streamlines. The transport equation includes linear equilibrium reversible sorption (retardation) and diffusion
from fractures into the rock matrix and v.v. FRACGEN generates synthetic fracture networks for sensitivity
analysis with respect to fracture network parameters.
Contact Address: D.D. Evans, Dept. of Hydrology and Water Resources, Univ. of Arizona, Tuscon, AZ
85721
F-1-9
-------
Appendix F: Flow and Transport in Fractured Rock, Part 2: Usability and Reliability
IGWMC
Key
581
582
584
588
589
695
2034
2581
2582
3083
3232
3238
3374
3790
3842
4031
4270
4470
4550
4590
Model
FTRANS
GREASE
STAFAN
SEFTRAN
TRAFRAP
NETFLO
SHALT
MULKOM
TOUGH
ROCMAS-THM
FRACFLOW
PORFLOW-3D
FRACPORT
PORFLO
SWIFT HI/386
TRUCHN/ZONE
TRACR3D
FRACTEST
MOTIF
MAGNUM-2D
Usability
Preprocessor
N
N
N
Y
N
N
U
U
U
U
Y
Y
U
Y
Y
U
U
U
U
U
Postprocessor
N
N
N
Y
N
N
U
U
U
U
Y
Y
U
Y
Y
U
U
U
u
u
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
Y
N
N
U
N
N
N
Y
Y
N
Y
Y
N
N
U
N
N
o
Q.
CL
M
N
N
N
N
N
N
U
L
L
U
Y
Y
U
Y
Y
L
L
U
L
U
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
Y
U
Y
U
N
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
Verified
L
L
L
L
L
L
L
L
L
L
E
E
L
L
E
L
L
U
E
L
Field Tested
N
L
L
L
N
U
U
U
U
U
L
L
U
L
L
L
U
U
L
L
e
1
3
o
F
F
F
M
F
F
U
F
F
U
F
M
U
F
M
F
U
U
F
F
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
F-2-1
-------
Appendix F, part 2 (continued)
IGWMC
Key
4600
4710
5003
5022
5025
5320
5640
5660
5680
6660
6810
Model
SANGRE
STAFF2D
MLU
3-D FE DUAL
POROSITY
NEFTRAN
3D FRACTURE
GENERATOR
NETFLO/
NETRANS
FLASH
FRANET
CRACK
BIM/FRACGEN
Usability
Preprocessor
U
Y
Y
U
N
N
U
N
N
Y
U
Postprocessor
U
Y
Y
U
N
N
U
N
N
Y
U
User's Instructions
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
U
Y
Y
U
N
N
U
N
N
Y
U
o
a.
a.
U)
u
L
L
U
N
N
U
L
N
Y
U
Reliability
Peer Reviewed Theory
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Peer Reviewed Coding
U
U
U
U
U
N
U
U
U
U
U
Verified
L
L
L
L
L
L
U
L
L
L
L
Field Tested
U
L
U
U
L
N
U
L
U
L
u
s
o
3
0>
•o
o
F
F
F
U
U
U
U
F
U
M
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
F-2-2
-------
Appendix G: Hydrogeochemical Models, Part 1: Model Description
IGWMC Key: 124 Model Name: DYNAMIX Released: 1988
Authors: Narasimhan, T.N., Liu, C.W.
DYNAMIX is a redox-controlled multi-species, multidimensional reactive chemical transport model. It couples
the chemical speciation code PHREEQE with the transport code TRUMP. The program includes acid-base
reactions, aqueous complexation, redox reactions, precipitation-dissolution reactions and kinetic mineral
dissolution. A search routine based on minimizing Gibbs free energy is used to identify the correct mineral
assemblage during the equilibrium calculation. The transport equations of each chemical component are
solved using the integral finite difference method. DYNAMIX uses a two-step dynamic mixing approach to
solve the equations of chemical transport and chemical equilibrium.
Contact Address: T.N. Narasimhan, Dept. of Materials Sc. and Mineral Eng., Univ. of Calif., Berkeley,
CA 94720
IGWMC Key: 2610 Model Name: PHREEQE Released: 1992
Authors: Parkhurst, D.L, Thorstenson, D.C., Plummer, L N.
PHREEQE is an equilibrium geochemical speciation and reaction path model that calculates mass transfer
as a function of stepwise temperature change or dissolution. Based on an ion-pairing aqueous model,
PHREEQE can calculate Ph, redox potential, and mass transfer as a function of reaction progress. The
original version included redox reactions and ion exchange for 19 elements, 120 aqueous species, 3 gases,
21 minerals. A series of coupled chemical equations are solved iteratively to yield the following: Ph, Eh, total
concentration of elements, amount of minerals (or other phases) transferred into or out of the aqueous
phase, distribution of aqueous species, and the saturation state of the aqueous phase with respect to
specified mineral phases.
Contact Address: U.S. Geol. Survey, Water Resources Div., Nat. Center, Reston, VA 22092; or
Internal. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 2611 Model Name: PHRQPITZ Released: 1988
Authors: Plummer, L.N., Parkhurst, D.L, Fleming, G.W., Dunkle, S.A.
PHRQPITZ is a code capable of making geochemical calculations in brines and other electrolyte solutions
to high concentrations using Pitzer virial coefficient approach for activity-coefficient corrections.
Reaction-modeling capabilities include calculation of 1) aqueous speciation and mineral saturation index,
2) mineral solubility, 3) mixing and titration of aqueous solutions, 4) irreversible reactions and mineral-water
mass transfer, and 5) reaction path. The computed results for each aqueous solution include the osmotic
coefficient, water activity, mineral saturation indices, mean and total activity coefficients, and
scale-dependent values of pH, individual-ion activities, and individual-ion activity coefficients. It includes a
data-base of Pitzer interaction parameters.
Contact Address: Water Resources Div., U.S. Geol. Survey, 432 National Ctr., Reston, VA 22092; or
Internat. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
G-1-1
-------
Appendix G, part 1 (continued)
IGWMC Key: 3084 Model Name: CHNTRNS Released: 1987
Authors: Noorishad, J., Carnahan, C.L, Benson, L.V.
CHMTRNS is a temperature-dependent non-equilibrium reactive chemical transport code, based on the
CHEMTRN code (Miller and Benson) developed in the early 1980's. Equations solved include mass balance,
aqueous species transport, non-equilibrium reactions, transport of hydrogen and hydroxide ions, equilibrium
complexation, dissolution and precipitation, ion exchange, redox reactions, and heat transport. The code
is capable of simulating kinetic calcite and silicate dissolution, irreversible glass dissolution, oxidation and
reduction, and stable carbon isotope fractionation during transport. The code can handle Neumann and
Dirichlet boundary conditions and includes a mesh generation scheme. The 1 -D transport equation is solved
using a upstream weighted finite difference algorithm.
Contact Address: Lawrence Berkeley Lab., Earth Sciences Div., Univ. of Calif., Berkeley, CA 94720
IGWMC Key: 3400 Model Name: BALANCE Released: 1992
Authors: Parkhurst, D.L, Plummer, L.N., Thorstenson, D.C.
BALANCE is a reaction model designed to define and quantify chemical reactions between groundwater and
minerals. It uses the chemical composition of water samples from two points along a flow path and a set
of mineral phases (minerals, organic substances, or gases) hypothesized to be the reactive constituents in
the system to calculate the mass transfer necessary to account for the observed changes in composition
between the two water samples. Additional constraints can be included in the problem formulation to
account for mixing of two end-member waters, redox reactions, and, in a simplified form, isotropic
composition. BALANCE solves any set of linear equations formulated by the user and is not constrained
by thermodynamic criteria.
Contact Address: U.S. Geol. Survey, Water Resources Div., Federal Center, Lakewood, CO 80225; or
Internal. Ground Water Modeling Ctr., Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 3611 Model Name: CHMTRNS Released: 1987
Authors: Noorishad, J., Carnahan, C.L, Benson, V.
CHMTRNS is a one-dimensional hydrochemical model that uses 2-step coupling between chemical relations
and transport equations. It includes kinetics and carbon-13 fractionation in addition to equilibrium
calculations. The model handles precipitation and dissolution. Sorption is modeled by ion exchange and
surface complexation. Activity coefficient is calculated by Davies equation.
Contact Address: Lawrence Berkeley Lab., Earth Sc. Div., Univ of Calif., Berkeley, CA 94720
IGWMC Key: 3620 Model Name: WATEQF Released: 1984
Authors: Plummer, L.N., Jones, B.F., Truesdell, A.H.
WATEQF is a program to model the thermodynamic speciation of inorganic ions and complex species in
solution for given water analysis. Processes included are mass balances and redox reactions, (see also
WATEQ2/WATEQ4F
Contact Address: U.S. Geol. Survey, Water Resources Div., Nat. Center, Reston, VA 22092
G-1-2
-------
Appendix G, part 1 (continued)
IGWMC Key: 3621 Model Name: NETPATH Released: 1992
Authors: Plummer, L.N., Prestemon, E.G., Parkhurst, D.L
NETPATH is an interactive program for the interpretation of net geochemical mass-balance reactions
between an initial and final water along a hydrologic flow path. Alternatively, NETPATH computes the mixing
proportion of a final water. The program utilizes previously defined chemical and isotopic data for waters
from a hydrochemical system. Every possible geochemical mass balance reaction model is examined
between selected evolutionary waters for a set of chemical and isotopic constraints, and a set of plausible
phases in the system. The calculations are of use in interpreting geochemical reactions, mixing proportions,
evaporation and (or) dilution of waters, and mineral mass transfer in the chemical and isotopic evolution of
natural and environmental waters.
Contact Address: Nat. Water Inform. System, U.S. Geol. Survey, 437 Nat. Ctr., Reston, VA 22092; or
Internat. Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 4450 Model Name: TRANQL/MICROQL Released: 1985
Authors: Cederberg, G.A., Street, R.L, Leckie, J.O.
TRANQL is a finite element transport model for simulation of multi-component solute transport with
equilibrium interaction chemistry coupled with 1-D advective-dispersive finite element transport. Significant
equilibrium reaction such as complexation, ion exchange, competitive adsorption, and dissociation of water
may be included. It includes to models for ion-exchange, the constant capacity model and the triple-layer
model. The model has been applied to cadmium, chloride, and bromide transport in a 1 -D column.
Contact Address: G.A. Cederberg, 2305 A 37th Street, Los Alamos, NM 87544
IGWMC Key: 4810 Model Name: EQ3/EQ6 Released: 1988
Author: Wolery, T.J.
EQ3 is a geochemical aqueous speciation/solubility program that can be used alone or in conjunction with
EQ6, which performs reaction-path calculations. EQ3 calculates the distribution of chemical species (ions,
neutral species, ion-pairs, and complexes). The program EQ3/EQ6 accommodates 47 elements, 686
aqueous species, 15 gases, over 16 redox elements, and 716 minerals. The code embodies a
ion-association conceptual model of solution behavior and simulates geochemical reactions using
Newton-Raphson solution method. The code requires geochemical data for each solid, gaseous or
dissolved chemical species being modeled. The data bases accompanying the code are for testing
purposes only. A separate precipitation kinetics option has been added.
Contact Address: K.J. Jackson, Lawrence Livermore Lab., Livermore, CA 94550
IGWMC Key: 4820 Model Name: EQUILIB Released: 1981
Authors: Morrey, J.R., Shannon, D.W.
EQUILIB models chemical equilibria in geothermal brines at various elevated temperatures (0 - 300 degrees
C). Its data base contains 26 elements, 200 aqueous species, 7 gases, 186 minerals, and it includes 9 redox
reactions. The code uses ligand projection method of solution, and the activity coefficient is provided by
the extended Debye-Huckel equation. It has been verified and partially validated by comparing it to four
other geochemical codes and to five laboratory experiments. EQUILIB has been applied to studying mineral
formation and corrosion in geothermal brines.
Contact Address: Electric Power Research Inst, P.O.Box 10412, Palo Alto, CA 94303
G-1-3
-------
Appendix G, part 1 (continued)
IGWMC Key: 4830 Model Name: GEOCHEM Released: 1980
Authors: Sposito, G., Mattigod, S.V.
GEOCHEM is a program for predicting the equilibrium distribution of chemical species in soil solution and
other natural water systems. The programs data base includes 45 elements, 1853 aqueous species, 889
organic ligands, 3 gases, and 250 minerals and solids. It includes a mass balance for each species and can
handle 7 redox reactions and cation adsorption and exchange. The Newton-Raphson solution method is
used, and a Davies equation provides the activity coefficient. Sorption is handled by a surface complexation
model.
Contact Address: G. Sposito, Dept. of Soil and Environm. Sc., Univ. of California, Riverside, CA 92521
IGWMC Key: 4840 Model Name: MINEQL2 Released: 1980
Authors: Westall, J.C., Zachary, J.L, Morel, F.M.M.
MINEQL2 is a program for the calculation of chemical equilibria in aqueous systems. It includes mass
balance calculations for each component, redox reactions, and surface adsorption.
Contact Address: F.M.M. Morel, Massachusetts Inst. of Technology, Dept. of Civil Eng., Cambridge,
MA 02139
IGWMC Key: 4850 Model Name: MINTEQ/MINTEQ2/MINTEQA2 Released: 1987
Authors: Felmy, A.R., Girvin, D.C., Jenne, E.A.
MINTEQ is a user-friendly program for calculation of the equilibrium behavior of various metals. It includes
a complex series of reactions among solution species, gases, solids, and sorbed phases, including ion
speciation/solubility, adsorption, gas phase equilibria, and precipitation/dissolution of solid phases. The
thermodynamic data in MINTEQ was taken from the WATEQ3 data base and has been further expanded
and updated using published critical reviews. Originally, MINTEQ included 31 elements, 373 aqueous
species, 3 gases, and 328 solids. Its data base is being updated on a regular basis. The program calculates
mass balance for each component, and includes redox reactions, ion exchange and six surface
complexation models.
Contact Address: E.A. Jenne, Battelle Pacific NW Laboratory, P.O. Box 999, Richland, WA 99352; or
CEAM, Environm. Res. Lab., US EPA, Athens, GA 30613-0801.
IGWMC Key: 4851 Model Name: MININR/MINICUP Released: 1983
Authors: Felmy, A.R., Reisenauer, A.E., Zachora, J.M., Gee, G.W.
MININR is a reduced form of the computer program MINTEQ which calculates equilibrium
precipitation/dissolution of solid phases, aqueous speciation, adsorption, and gas phase equilibrium. The
user-oriented features in MINTEQ were removed to reduce the size and increase the computational speed.
MININR closely resembles the MINEQL program, their main differences being modifications to accept an
initial starting mass of solid and necessary changes for linking with a water flow model. The thermochemical
data are passed to MININR by a run from MINTEQB. MININR has been linked with the one-dimensional
SATCOL saturated flow model in a code called MINICUP.
Contact Address: Battelle Pacific Northwest Lab., Environm. Res. Group, Richland, WA 99352
G-1-4
-------
Appendix G, part 1 (continued)
IGWMC Key: 4860 Model Name: PROTOCOL Released: 1984
Authors: Pickrell, G., Jackson, D.D.
PROTOCOL (PROgram TO Correlate Leaching data) is a coupled kinetic/equilibrium program for
calculating dissolution reactions of inorganic solids in aqueous solution, with specific application to corrosion
of vitrified nuclear waste by groundwater. PROTOCOL was designed to function as a generic simulator
without specific rate expressions or leaching mechanisms. Such functions may be input to the program as
submodels. Initially three submodels have been incorporated. The program incorporates equilibrium
routines from the program MINEQL and includes an extensive thermodynamic data base.
Contact Address: D.D. Jackson, Lawrence Livermore Lab., Univ. of Calif., L-329, Livermore, CA 94550
IGWMC Key: 4870 Model Name: REDEQL-EPA Released: 1978
Authors: Ingle, S.E., Schuldt, M.D., Schults, D.W.
REDEQL.EPA is a program to compute aqueous equilibria for up to 20 metals and 30 ligands in a system.
It includes 46 elements, 94 aqueous species, 2 gases, and 13 minerals/solids. It calculates mass balances,
and handles precipitation, redox reactions, complexation and pH-dependent phenomena.
Contact Address: D.W. Schults, Hatfield Marine Sciences Center, US EPA, Newport, OR 97365
IGWMC Key: 4871 Model Name: REDEQL-UMD Released: 1984
Authors: Harriss, O.K., Ingle, S.E., Taylor, O.K., Magnuson, V.R.
REDEQL-UMD is a program to compute equilibrium distributions of species concentrations in aqueous
systems. The basic equilibria which may be treated include complexation, precipitation, oxidation-reduction,
and adsorption. The standard version allows simultaneous consideration of reactions involving 20 metals
and 30 ligands. Similarly, up to 20 redox reactions can be handled. The accompanying data base includes
relevant data on the metals and ligands, thermodynamic stability constants for complexes, mixed complexes,
redox reactions, solids, and mixed solids, and includes 53 elements, 109 aqueous species, and 158 minerals.
It calculates the mass balance of each species.
Contact Address: V.R. Magnuson, Dept. of Chemistry, Univ. of Minnesota, Duluth, MN 55812
IGWMC Key: 4880 Model Name: SOLMNEQ/SOLMNEQF Released: 1988
Authors: Kharaka, Y.K., Barnes, I.
SOLMNEQ is a program, originally written in PL/1, for computing the equilibrium distribution of species in
aqueous solution over a temperature range of 0 to 350 degrees C. The program includes 26 elements, 162
aqueous species, and 158 minerals. It calculates the mass balance of each element and includes redox
reactions. The logic of the program has been developed in part following the logic of WATCHEM and
WATEQF. A FORTRAN version was published in 1988 as SOLMNEQF. SOLMNEQF calculates the
equilibrium distribution of 236 species including uranium, vanadium, and 18 organic species of acetate,
oxalate, and succinate, as well as the saturation states of 196 minerals (see remarks)
Contact Address: Y.K. Kharaka, U.S. Geol. Survey, 345 Middlefield Road, Menlo Park, CA 94025
G-1-5
-------
Appendix G, part 1 (continued)
IGWMC Key: 4881 Model Name: SOLMNQ Released: 1983
Authors: Goodwin, B.W., Munday, M.
SOLMNQ is an interactive chemical speciation program that calculates equilibrium distributions for inorganic
aqueous species often found in groundwater. The program is based on the SOLMNEQ program published
in 1973. It includes 28 elements, 239 aqueous species and 181 solids. The program calculates the mass
balance for each species of uranium and plutonium and handles redox reactions.
Contact Address: Atomic Energy of Can., Whiteshell Nucl. Res. Establ., Pinawa, Manitoba ROE 1LO,
Canada
IGWMC Key: 4882 Model Name: SOLMINEQ.88 Released: 1988
Authors: Kharaka, Y.K., Gunter, W.D., Aggarwal, P.K., Perkins, E.H., et Al.
SOLMINEQ.88 is an updated version of SOLMNEQ, first published in 1973, SOLMNEQF (1986), and several
unpublished versions of the code. The computer program can be used to model speciation, saturation,
dissolution/precipitation, ion exchange/adsorption, mixing, boiling, and gas partitioning between water, oil,
and gas phases. The program is especially useful for modeling water-rock interactions in sedimentary basins
where high temperatures, pressures, salinities, and dissolved organic species prevail. SOLMINEQ.88 has
a database of 260 inorganic and 80 organic aqueous species and 220 minerals. It computes the activity
coefficients in brines using Pitzer equations, and computes pH and mineral solubilities at subsurface
temperatures and pressures.
Contact Address: U.S. Geol. Survey, 345 Middlefield Road, Menlo Park, CA 94025
IGWMC Key: 4890 Model Name: WATEQ2/WATEQ4F Released: 1991
Authors: Ball, J.W., Jenne, E.A., Nordstrom, O.K.
WATEQ2, written in PL/1, is a chemical equilibrium model for calculating aqueous speciation of major and
minor elements among naturally occurring ligands. It uses field measurements of temperature, pH, Eh,
dissolved oxygen and alkalinity, and the chemical analysis of a water sample as input and calculates and
calculates the distribution of aqueous species, ion activities, and mineral saturation indices that indicate the
tendency of a water to dissolve or precipitate a set of minerals. The program solves a set of nonlinear
mass action and mass balance equations using the continued fraction method. WATEQ2 is a modified
version of WATEQ (1974) and WATEQF (1976). WATEQ4F is an updated version, written in FORTRAN 77.
Contact Address: U.S. Geol. Survey, 345 Middlefield Road, Menlo Park, CA 94025; or Internal.
Ground Water Modeling Ctr, Colorado Sch. of Mines, Golden, CO 80401.
IGWMC Key: 4891 Model Name: WATEQ3 Released: 1982
Authors: Ball, J.W., Jenne, E.A., Cantrall, M.W.
WATEQ3 is a chemical equilibrium model for calculating aqueous speciation of major and minor elements
among naturally occurring ligands, including uranium species. The program, which is based on WATEQ2,
calculates the mass balance of the species and handles redox reactions and gases. The Newton-Raphson
solution technique is used to solve for 30 elements, 227 aqueous species, 12 organic ligands, and 309
precipitation/dissolution minerals. The activity coefficient is calculated by the Debye-Huckel equation. The
thermodynamic data base of the code is probably the most thoroughly documented and evaluated of any
available. WATEQ3 has been used extensively in field ground water investigations of the USGS.
Contact Address: U.S. Geol. Survey, 345 Middlefield Road, Menlo Park, CA 94025
G-1-6
-------
Appendix G, part 1 (continued)
IGWMC Key: 4990 Model Name: SENECA Released: 1981
Authors: Ma, Y.H., Shipman, C.W.
SENECA computes equilibrium compositions in a two-step process. The first step uses the free-energy
minimization procedure to obtain an approximate composition of the system. The second step uses this
approximate composition as an initial estimate for solving a set of mass-balance and mass-action equations
by the Newton-Raphson method. Version 2 includes a permanent arrangement for an aqueous phase, a
gas phase, and multiple solid phases; an activity coefficient calculation for aqueous species;
oxidation-reduction reactions; and a thermodynamic data base for 70 complexes, gases and solids.
Contact Address: J.F. Kerrisk, Los Alamos Nat. Lab., P.O. Box 1663, Los Alamos, NM 87545
IGWMC Key: 5033 Model Name: FOWL Released: 1992
Authors: Hosteller, C.J., Erikson, R.L, Rai, D.
The FOWL (FOssil fuel combustion WasteLeaching) computer code allows the user to calculate the
chemical composition, quantity, and release duration of leachates of fossil fuel combustion byproducts
disposed of in ponds and landfills. The basis of FOWL is formed by precipitation-dissolution reactions at
equilibrium with a given solid phase and solubility relationships based on laboratory and field data. The
model assumes that these solid phases do not change rapidly and that thermodynamic equilibrium applies
throughout the leaching time period. The FOWL code uses geochemical and water balance methods to
calculate leachate composition and quantity over time. The model output provides the source term for
subsequent transport and fate modeling.
Contact Address: Electric Power Research Inst., Box 10412, Palo Alto, CA 94303
IGWMC Key: 5840 Model Name: FASTCHEM Released: 1988
Authors: -
FASTCHEM (Fly Ash and Scrubber sludge Transport and geoCHEmistry Model) simulates hydrologic and
geochemical processes of inorganics in saturated and unsaturated media.
Contact Address: Electric Power Research Inst., P.O. Box 10412, Palo Alto, CA 94303-9743
IGWMC Key: 6701 Model Name: CHROMAT Released: 1991
Authors: --
CHROMAT (CHROMium ATenuation evaluation model) calculates Cr concentration and attenuation as
Cr-based leachate migrates through porous soils.
Contact Address: Electric Power Research Inst., P.O. Box 10412, Palo Alto, CA 94303-9743
G-1-7
-------
Appendix G: Hydrogeochemical Models, Part 2: Usability and Reliability
IGWMC
Key
124
2610
2611
3084
3400
3611
3620
3621
4450
4810
4820
4830
4840
4850
4851
4860
4870
4871
4880
4881
Model
DYNAMIX
PHREEQE
PHRQPITZ
CHNTRNS
BALANCE
CHMTRNS
WATEQF
NETPATH
TRANQL/
MICROQL
EQ3/EQ6
EQUILIB
GEOCHEM
MINEQL2
MINTEQ/
MINTEQ2/
MINTEQA2
MININR/
MINICUP
PROTOCOL
REDEQL-EPA
REDEQL-UMD
SOLMNEQ/
SOLMNEQF
SOLMNQ
Usability
Preprocessor
N
Y
N
U
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U
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Y
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Y
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Y
Y
Y
Y
Y
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Sample Problems
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Hardware Dependency
N
N
N
N
N
N
N
N
U
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N
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Y
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U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
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U
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L
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U
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U
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KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
G-2-1
-------
Appendix G, part 2 (continued)
IGWMC
Key
4882
4890
4891
4990
5033
5840
6701
Model
SOMINEQ.88
WATEQ2/
WATEQ4F
WATEQ3
SENECA
FOWL
FASTCHEM
CHROMAT
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-------
Appendix H: Optimization Model for Ground-water Management, Part 1: Model Description
IGWMC Key: 260 Model Name: DELTA Released: 1981
Authors: Morel-Seytoux, H.J., Rodriquez, C., Daly, C.
DELTA is a conjunctive use stream-aquifer model. It simulates two-dimensional transient areal groundwater
flow in a confined or unconfined heterogeneous, isotropic aquifer and the quasi one-dimensional flow in a
connected river. It calculates aquifer drawdown, river stage and aquifer return flow with the finite difference
method. The model uses stream-aquifer response coefficients (discrete kernels) and mathematical
programming for optimization. The decision variables are pumping rates, upstream river inflows, initial
drawdown and recharge rates.
Contact Address: H.J. Morel-Seytoux, Colorado State Univ., Engineering Research Center, Fort
Collins, CO 80523
IGWMC Key: 2060 Model Name: DELTIS Released: 1981
Authors: Morel-Seytoux, H.J., Illangasekare, T.
DELTIS is a stream-aquifer discrete kernel generator for horizontal confined or unconfined, transient ground
water flow in isotropic, heterogeneous aquifers using the finite element technique. It can be used together
with a mathematical programming package to determine optimal conjunctive use of surface water and
groundwater resources.
Contact Address: H.J. Morel-Seytoux, Engineering Research Center, Colorado State University, Fort
Collins, CO 80523
IGWMC Key: 2061 Model Name: DELPET - Discrete Kernel Generator Released: 1977
Authors: Morel-Seytoux, H.J., Daly, C.J., Peters, G.
DELPET is a discrete kernel generator for transient horizontal flow in an isotropic, heterogeneous, confined
or unconfined aquifer to simulate drawdowns and return flows using the finite difference technique. It can
be linked to a mathematical program package to optimize the location and pumping rates of wells.
Contact Address: H.J. Morel-Seytoux, Colorado State Univ., Engineering Research Center, Fort
Collins, CO 80523
IGWMC Key: 3092 Model Name: AQMAN (AQuifer MANagement) Released: 1986
Authors: Gorelick, S.M., Lefkoff, LJ.
Used in conjunction with a mathematical programming code (e.g. MPS), AQMAN identifies the pumping or
recharge strategy that achieves a user's management objective while maintaining groundwater hydraulic
conditions within desired limits. The objective may be linear or quadratic, and may involve the minimization
of pumping and recharge rates or of variable pumping costs. The problem may contain constraints on
groundwater heads, gradients, and velocities for a complex, transient hydrologic system. A unit stress is
applied at each decision point well and transient responses are computed using a modified two-dimensional
finite difference flow model of the USGS. The program is based on the use of the response matrix
optimization method.
Contact Address: WATSTORE Program Office, U.S. Geol. Surv., 437 Nat. Center, Reston, VA 22092
H-1-1
-------
Appendix H, part 1 (continued)
IGWMC Key: 3190 Model Name: GRNDFLO Released: 1978
Authors: Loganathan, G.V., Delleur, J.W., Tavalage, J.
GRNDFLO is a steady-state finite element model for simulation of ground-water flow in a confined,
anisotropic, heterogeneous aquifer. It uses linear triangular elements and has an automatic mesh generating
scheme. Boundary conditions include prescribed head and prescribed flow. GRNDFLO and the water
demand model LANDUSE are included in the management model WATSUP, which uses a mixed integer
programming formulation for the optimization of the water distribution system.
Contact Address: Delleur, J.W., Purdue University, School of Civil Engineering, West Lafayette,
Indiana, 47907
IGWMC Key: 3191 Model Name: WATSUP Released: 1978
Authors: Logannathan, G.V.,Delleur, J.W., Tavalage, J.J.
The purpose of WATSUP is to determine optimal location of water wells and of distribution reservoirs along
with optimal flow values and pipe sizes in an urban growth area.
Contact Address: Delleur, J.W., Purdue Univ., School of Civil Eng., West Lafayette, Indiana, 47907
IGWMC Key: 3983 Model Name: MODMAN (MODflow MANagement) Released: 1990
Authors: -
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, #100, Sterling, VA 22170
MODMAN is a program developed to add management capability to the USGS modular 3-D flow model
MODFLOW. MODMAN in conjunction with optimization software, provide optimal locations of pumping and
injection wells and optimal pumping or recharge rates for these well. The optimal solution maximizes or
minimizes a user-defined objective function, such as maximizing total pumping rate from all wells, and
satisfies all user-defined constraints, such as upper and lower limits on heads, gradients, and pumping rates.
MODMAN utilizes the response matrix technique to transform the groundwater management problem into
a linear or mixed-integer program. MODFLOW is called repeatedly as a subroutine. The program requires
an external optimization program not included in MODMAN.
IGWMC Key: 4070 Model Name: GWUSER/CONJUN Released: 1983
Author: Kolterman, C.R.
GWUSER/CONJUN is a combined simulation-optimization model to determine optimal pumping locations
and pumping rates for a confined aquifer with or without artificial recharge (GWUSER) or to determine the
optimal conjunctive use of an aquifer-stream system (CONJUN). The simulation model is based on a finite
difference approximation of transient groundwater flow and linear programming solution of the optimalization
problem.
Contact Address: C.R. Kolterman, Desert Research Institute, Reno, Nevada
H-1-2
-------
Appendix H: Optimization Models for Ground-water Management, Part 2: Usability and Reliability
IGWMC
Key
260
2060
2061
3092
3190
3191
3983
4070
4480
6703
Model
DELTA
DELTIS
DELPET
AQMAN
GRNDFLO
WATSUP
MODMAN
GWUSER/
CONJUN
GWMAN
OPTIC
Usability
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H-2-1
-------
Appendix H, part 1 (continued)
IGWMC Key: 4480 Model Name: GWMAN Released: 1984
Authors: Wanakule, N., Mays, N.W., Lasdon, LS.
GWMAN is a computer program for determining optimal pumping and recharge of large scale artesian
and/or non-artesian aquifers by coupling non-linear optimization with an existing finite difference simulator
for transient horizontal flow in anisotropic, heterogeneous aquifers. The state variables which represent the
heads, and the control variables which represent pumpages, are implicitly related through the groundwater
simulator. The simulator equations are used to express the system states in terms of the controls, yielding
so-called reduced problem functions. The reduced problem is solved by combining augmented Lagrangian
and reduced gradient procedures. Both steady-state and transient type dewatering problems are solved.
Contact Address: N.W. Mays, Center for Research in Water Resources, Univ. of Texas at Austin,
Austin, TX 78712
IGWMC Key: 6703 Model Name: OPTIC Released: 1992
Authors: -
OPTIC (Optimal Pumping To Immobilize Contaminants) calculates optimum pumping rate to hydraulically
contain a contaminated ground water plume.
Contact Address: Electric Power Research Institute, P.O. Box 10412, Palo Alto, CA 94303-9743
Note: Only few models have been designed as general-use models. Often, they require the user to have
access to a mathematical optimization package on their computer system. Many research models
have been discussed in the literature; for most of them no code is available.
H-1-3
-------
Appendix I: Multiphase Flow, Part 1: Model Description
IGWMC Key: 4420 Model Name: GASOLINE Released: 1984
Author: Baehr, A.L
GASOLINE is a one-dimensional finite difference research model to solve a system of equations defining the
transport of an immiscible contaminant immobilized in the unsaturated zone, with and without
biodegradation. The program handles capillary forces, advection, dispersion, diffusion, linear adsorption,
redox reactions, and biological activity.
Contact Address: Baehr, A.L., U.S. Geological Survey, Water Resources Div., Trenton, NJ 08628
IGWMC Key: 4650 Model Name: SWANFLOW Released: 1992
Authors: Faust, C.R., Rumbaugh, J.D.
SWANFLOW is a public domain, multi-dimensional finite difference model for simulation of simultaneous flow
of water, air and immiscible non-aqueous phase liquids (NAPL's) within and below the vadose zone. The
conservation equations for mass and momentum of water, gas (air), and a NAPL are simplified to yield two
strongly coupled nonlinear partial differential equations. Pressure gradients in the air phase are considered
negligible; air pressure is assumed to be constant and equal to atmospheric pressure. The model
determines the spatial and temporal distribution of NAPL pressure and water saturation. Acceptable
boundary conditions are: specified flux, fluid potential and fluid potential-dependent flux. There are three
primary limitations to the code: 1) the air phase is considered to be at constant atmospheric pressure, thus
flow of air is not modeled; 2) mass transfer between phases is not considered, i.e. NAPL cannot dissolve
in water or evaporate; 3) practical application of the code to field problems can be complicated by lack of
site-specific capillary pressure and relative permeability. A user-friendly, proprietary two-dimensional version
is also available.
Contact Address: GeoTrans, Inc., 46050 Manekin Plaza, Suite #100, Sterling, VA 22170; for 3-D
version also Internal. Ground Water Modeling Center, Colorado School of Mines,
Golden, Co 80401.
IGWMC Key: 5180 Model Name: MOFAT Released: 1990
Authors: Kaluarachchi, J.J., Parker, J.C.
MOFAT is an upstream-weighted finite element model to simulate coupled flow of water, nonaqueous phase
liquid (NAPL) and air, and multicomponent transport of up to five non-inert species in a two-dimensional
vertical section through saturated and unsaturated zones in Cartesian or radial coordinates. The flow
module can be used to simulate 2- or 3-phase system with gas phase treated dynamically or assumed at
constant pressure. Convecth/e-dispersive transport in water, NAPL and gas phase is analyzed assuming
local equilibrium partitioning among phases and with the solid phase. MOFAT comes with pre- and
post-processing capabilities. Only rectangular elements with sides parallel to the principle flow axes are
permitted.
All flow simulations in MOFAT can be performed using either van Genuchten or Brooks-Corey soil properties.
The program is dimensioned to handle 1500 nodes with 10 different material properties, 50 type-1 boundary
nodes and 100 flux-type boundary elements, and 25 boundary condition cycles with 4 subcycles per cycle.
A maximum of two seepage faces are allowed with a maximum of 50 nodes along any seepage face for a
given phase. To run MOFAT the following data is required: mesh geometry, boundary condition parameters,
continued
1-1-1
-------
Appendix H, part 1 (continued)
MOFAT - continued
simulation control parameters, initial distribution of heads, porosity, van Genuchten's n, van Genuchten's
alpha, residual water saturation, scaling parameter for air-NAPL interfacial tension, NAPL-water interfacial
tension, ratio of NAPL to water density, ratio of NAPL to water viscosity, maximum NAPL residual saturation,
saturated hydraulic conductivity, dispersivfty, and equilibrium coefficients for NAPL/water, air/water, and
soil/water. Other required input for MOFAT includes first-order decay coefficients for each species in water,
NAPL, air, and soil phases; diffusion constants in water, NAPL and air; and liquid density of the pure species.
Contact Address: Environmental Systems and Technologies Inc., P.O. 10457, Blacksburg, VA 24062-
0457; or Internal. Ground Water Modeling Center, Colorado School of Mines,
Golden, CO 80401.
IGWMC Key: 5181 Model Name: SPILLVOL Released: 1990
Authors: Parker, J.C., Lenhard, R.J.
SPILLVOL is an interactive menu-driven program to estimate areal hydrocarbon distributions and integrated
volumes from well fluid level data. The program can be used to determine: 1) current volume of "free"
hydrocarbon in the soil; 2) the current residual product volume associated with historical fluid level
variations; and 3) the volume of hydrocarbon which can be recovered by skimming either without water
pumping or for a specified final water table configuration. Calculations are based on a physically-based
model for vertical equilibrium three phase fluid distributions which includes effects of oil entrapment in the
saturated zone and non-drainable residual oil in the unsaturated zone.
Soil properties are described in SPILLVOL using the van Genuchten capillary pressure model, the
parameters of which may be estimated by the program from grain size distribution data. The user also
supplies data from a network of observation wells on current depth to oil and depth to water, historical
minimum depth to oil and maximum depth to water, and anticipated future water table elevations.
Furthermore, the program gives information on areal distribution of uncertainty in volume estimates due to
uncertainty in soil properties, fluid properties and interpolation error.
Contact Address: Environmental Systems and Technologies Inc., P.O. 10457, Blacksburg, VA 24062-
0457; Internal. Ground Water Modeling Center, Colorado School of Mines, Golden,
CO 80401; or Scientific Software Group, Washington, D.C.
IGWMC Key: 5184 Model Name: ARMOS Released: 1992
Authors: Kaluarachchi, J., Parker, J.C., Zhu, J.L, Katyal, A.K.
ARMOS (Areal Multiphase Organic Simulator) is a numerical model to simulate areal flow of water and
separate phase light hydrocarbon in unconfined aquifers under natural gradients or forced gradients
associated with well or trench free product recovery systems. The model assumes vertical equilibrium
pressure distributions of water and hydrocarbon phases with consideration of residual hydrocarbon in the
saturated and unsaturated zones associated with water imbibition and oil drainage. The nonlinear governing
equations are solved using an upstream weighted finite element scheme with linear rectangular elements.
Nonlinearity is handled by Picard iteration. The model handles multiple recovery wells with water and
hydrocarbon pumping. Properties are based on van Genuchten model with hysteresis due to residual oil.
ARMOS is based on vertical integration of the governing flow equations under the assumption of
near-equilibrium conditions in the vertical direction with zero gas pressure gradients. The new version uses
continued
1-1-2
-------
Appendix H, part 1 (continued)
ARMOS - continued
a serial solution procedure for water and oil flow equations. Other options include simulation of hydrocarbon
flow only assuming steady-state water flow, or to model water flow only to facilitate calibration.
Input data for ARMOS include initial conditions prescribed as elevations of air-oil and oil-water fluid tables,
prescribed boundary conditions, soil properties, fluid properties and run-time parameters such as mesh data,
time increments and convergence criteria. Fluid properties required by ARMOS are viscosity, density and
surface tension of the hydrocarbon. Soil properties include the saturated hydraulic conductivity and
parameters defining the saturation-capillary pressure-relative permeability relations. Soil properties can vary
spatially. Initial conditions in ARMOS are specified by giving fluid level data from a set of observation wells
that are interpolated internally to define nodal air-oil and oil-water elevations. Boundary conditions can be
stipulated as prescribed fluid table elevations or fluid fluxes. Multiple recovery wells for free product
skimming with or without water pumping may be modeled.
The main output from ARMOS are predicted fluid table elevations and the total, free and residual oil volume
per unit area. For recovery well locations, water and oil pumping rates, cumulative recovery water and
hydrocarbon pumpage and well fluid levels are output. For each output time, the cumulative change in oil
volume, area of soil with free oil present and area of soil with residual or free oil present are given.
Contact Address: Environmental Systems and Technologies Inc., P.O. 10457, Blacksburg, VA 24062-
0457; Internal. Ground Water Modeling Center, Colorado School of Mines, Golden,
CO 80401; or Scientific Software Group, Washington, D.C.
IGWMC 5185 Model Name: MOTRANS Released: 1992
Authors: Katyal, A.K., Parker, J.C.
MOTRANS is a 2-dimensional vertical section or radially symmetric upstream-weighted finite element
program for flow of air, light or dense organic liquid and water, and coupled transport of up to 5 partionable
species. The program, which uses linear rectangular elements, allows inclusion or elimination of flow
equations for selected phases to achieve maximum flexibility and efficiency. Soil hydraulic properties are
described by the multi-phase van Genuchten model with NAPL entrapment. The nonlinearity in the
equations is handled by Newton-Raphson iteration. Multispecies transport is simulated assuming focal
equilibrium or kinetically controlled interphase mass transfer. Pre- and postprocessing modules are
available.
The flow module of MOTRANS can be used to analyze two-phase flow of water and NAPL in a system with
gas present but at constant pressure, or explicit three-phase flow of water, NAPL and gas at variable
pressure. Systems with no NAPL present or with immobile NAPL at a residual saturation may also be
modeled. The transport module can handle up-to five components that partition among water, NAPL, gas
and solid phases assuming either local equilibrium interphase mass transfer or first-order kinetically
controlled mass transfer. MOTRANS requires specification of parameters defining the air-water capillary
retention function, NAPL surface tension and interfacial tension with water, NAPL viscosity, NAPL density,
maximum residual NAPL saturation and soil hydraulic conductivity. The latter may be anisotropic and soil
properties may vary spatially. For transport analyses, additional data input include porous media
dispersivities, initial water phase concentrations, equilibrium partition coefficients, component densities,
diffusion coefficients, and first-order decay coefficients. Additional transport input data for MOTRANS: mass
transfer coefficients (for nonequilibrium analyses) and boundary condition data. Time dependent boundary
conditions for the flow analysis may involve user-specified phase heads at nodes or phase fluxes along a
continued
1-1-3
-------
Appendix H, part 1 (continued)
MOTRANS -- continued
boundary segment with zero flux as the default condition. For transport analysis, time-dependent boundary
conditions include equilibrium water phase concentrations or prescribed fluxes defined in terms of a
specified concentration in the influent liquid. If not specified, the b.c. is a zero dispersive flux. MOTRANS
calculates pressure heads, saturations and velocities for each phase at every node for specified output
intervals. In addition, the total volume of mass of each phase, time-step size and number of iterations are
given. For transport analysis, the phase concentrations at each node are computed. The program has a
restart option.
Contact Address: Environmental Systems and Technologies Inc., P.O. 10457, Blacksburg, VA 24062-
0457; or Internal. Ground Water Modeling Center, Colorado School of Mines,
Golden, CO 80401.
IGWMC Key: 5189 Model Name: SPILLCAD Released: 1992
Authors: -
SPILLCAD is a program for determining hydrocarbon spill volume. First, total petroleum hydrocarbon (TPH)
data from soil samples can be integrated directly to estimate total (residual and free) product within the
sampled zone. Also, the volume of free product floating on the water table can also be determined. This
latter is accomplished by determining the vertical distribution of hydrocarbon in the soil in equilibrium with
well fluid levels based on a theoretically rigorous treatment of the three phase saturation-capillary pressure
relations for the soil. Soil and fluid properties required to carry out the calculations can be estimated by the
program using a number of options. Finally, SPILLCAD enables the user to evaluate various free product
control and recovery options.
Procedures developed for estimation of hydrocarbon spill volume include interpolation and spatial
integration of TPH measurements from soil cores, and spatial integration of hydrocarbon volume per area
computed from monitoring well fluid levels. The first method involves vertical integration of TPH
measurements to yield oil volume per unit area followed by kriging and areal integration to estimate the
volume within the measurement zone. This method is especially well suited to determine the volume of
residual product in the unsaturated zone.-The second method involves kriging of well fluid levels,
calculation of free oil volume per area using a physically-based model for hydrostatic three-phase fluid
distributions, followed by areal integration to estimate the volume of free product floating on the water table.
An analytical procedure was developed to evaluate effects of steady-state water pumping from multiple point
sources on the oil flow gradients to enable hydraulic control of plume spreading. Estimates of residual oil
in the unsaturated and saturated zone are made from the hysteric three-phase capillary pressure-saturation
relations and from initial oil thickness distributions and computed water table drawdown, which enable
determination of the recoverable spill volume for alternative well configurations.-The PC implementation of
SPILLCAD operates within a graphical windowed environment. It is highly interactive and includes a
graphical data base system for management of spatial data.
Contact Address: Environmental Systems and Technologies Inc., P.O. 10457, Blacksburg, VA 24062-
0457; or Internal. Ground Water Modeling Center, Colorado School of Mines,
Golden, CO 80401.
1-1-4
-------
Appendix H, part 1 (continued)
IGWMC Key: 5280 Model Name: KOPT Released: 1989
Authors: Charbenau, C.J., Weaver, J.W., Smith, V.J.
KOPT (Kinematic Oily Pollutant Transport model) is a oily pollutant transport model, based on the kinematic
theory of one-dimensional multiphase flow. The model assumes steady infiltration of water. It is intended
to be a screening tool for hydrocarbon spills or near-surface releases. It addresses the questions of how
far an oil release might go into the soil and how soon it might get there. The solution is obtained by solving
an approximate governing equation for the water by the method of characteristics (MOC). With the proper
constitutive relationships for two-phase flow, the water solution is analytic. For the oily phase, a
semi-analytic solution has been developed. The model is based on advective transport and includes
(bio-)transformations, linear equilibrium sorption, and volatilization.
Contact Address: R.J. Charbenau, Univ. of Texas, Water Resources Research Center, Dept. of Civil
Eng., Austin, TX 78712
IGWMC Key: 5281 Model Name: KROPT Released: 1989
Authors: Charbenau, R.J., Weaver, J.W., Smith, V.J.
KROPT (Kinematic Rainfall and Oily Pollutant Transport model) is an oily pollutant transport model, based
on the kinematic theory for one-dimensional multi-phase flow. The model includes transient hydrologic
phenomena such as evaporation and infiltration, along with a model of stochastic generation of rainfall. The
model handles multiple loadings or releases of oily wastes at or near ground surface, multiple rainfall events,
potential oil migration, linear equilibrium sorption, volatilization, and biodegradation. The solution is obtained
by solving an approximate governing equation for the water by the method of characteristics (MOC). With
the proper constitutive relationships for two-phase flow, the water solution is analytic. For the oily phase,
a semi-analytic solution has been developed.
Contact Address: R.J. Charbenau, Univ. of Texas, Dept. of Civil Eng., Austin, TX 78712
IGWMC Key: 5681 Model Name: VIP Released: 1991
Authors: Stevens, O.K., Grenney, W.J., Van, Z.
VIP (Vadose zone Interactive Processes model) is an one-dimensional finite-difference solute transport and
fate model for simulating the behavior of organic compounds in the vadose zone as part of a land treatment
system. The model uses advection and dispersion in the water and air phases as the dominant transport
mechanism for contaminant and oxygen. Monthly values for recharge rate and soil moisture conditions are
used to calculate an effective water velocity. Volatilization is represented by mass flux into the air phase and
subsequent advection and dispersion. The model includes first-order degradation of a contaminant in water,
air and soil, and of oxygen. It uses an implicit technique to calculate the degradation of the contaminant
in the oil phase as well as the oil phase itself, and related oxygen changes.
VIP uses partition coefficients and rate constants to calculate contaminant concentration in each medium.
The model has various output options including echo of input data, (graphic) profile of initial condition
(constituent concentration in water, oil, air, and soil phases), and the initial fractions as well as initial oxygen
concentration. Other output options include (graphic) depth-concentration profiles and data versus time
tables. Input preparation facilitates exchange of Lotus 123 and word processed ASCII files. The pore
velocity in water is calculated by dividing the average infiltration rate by the water content of the soil as
estimated by the procedure of Clapp and Hornberger.
Contact Address: O.K. Stevens, Civil and Environm. Eng. Dept., Utah State Univ., UMC 4110, Logan,
UT 84321; or EPA/CSMoS, RSKERL, P.O. Box 1198, Ada, OK 74820
1-1-5
-------
Appendix H, part 1 (continued)
IGWMC Key: 5820 Model Name: MAGNAS Released: 1992
Authors: Huyakorn, P.S., Kool, J.
MAGNAS is a finite element model for simulation of 3D and 2D flow of water, NAPL (light or dense), and air
in heterogeneous and anisotropic porous media. Transport calculations include advection, dispersion in all
fluid phases, sorption, volatilization, dissolution, precipitation and degradation. Alternative pseudo 3-phase
and sharp interface formulations are available. The model can handle large contrasts in soil properties and
highly nonlinear constitutive relationships. The model converges well and provides an accurate mass
balance.
Contact Address: HydroGeologic Inc., 1165 Herndon Parkway, # 900, Herndon, VA 22070
IGWMC Key: 5821 Model Name: MAGICS Released: 1992
Authors: Huyakorn, P.S., et at.
MAGICS (Multiphase model for Air, Ground-water, Immiscible Contaminant and Solute transport) is a
Galerkin finite element model for simulation of the flow of water, nonaqueous phase liquid, and air through
porous media in two or three dimensions. MAGICS may be used to simulate the flow of air as a fully active
phase. The solute transport simulation accounts for advection and hydrodynamic dispersion in all fluid
phases, equilibrium sorption, volatilization, dissolution, precipitation and first-order degradation. As subsets
of the most general fully three-phase modeling approach, a variety of simpler flow formulations may be
simulated using the code. The fluid flow and solute transport simulations are performed sequentially.
Subsets of the full three-phase model in MAGICS includes pseudo-three-phase (with passive air phase),
two-phase and single phase flow. Additionally, a sharp-interface areal simulation option is provided to
handle situations where capillary pressure and relative permeability data is unavailable or a 3-D simulation
unwarranted. A wide range of boundary conditions can be treated including those involving influx and afflux
boundaries, water-table conditions, infiltration or recharge, and wells. The solution procedure for MAGICS
incorporates upstream weighing of nodal values of phase mobilities and storage matrix lumping for linear
rectangular elements. Element matrices are evaluated using enhanced influence-coefficient algorithms that
avoid numerical integration and take advantage of nodal connectivities. These algorithms produce 5-point
(finite difference) and 9-point (finite element) lattice in 2-D, and an 11-point (hybrid) lattice in 3-D.
Use of the hybrid approximation in MAGICS combines the advantages of the FD and FE techniques (e.g.
positive transmissivity and insensitivity of the numerical solution to grid orientation) for 3-D problems.
Nonlinearities are treated using a modified Newton-Raphson procedure with automatic under-relaxation and
aggressive time-stepping. A Picard scheme and single-step steady-state analysis are provided as options
in the single-phase flow formulations. For solute transport simulations, an upstream-weighted residual FE
procedure is used for the phase-summed equation. -The upstream weighing scheme for the solute transport
curbs numerical oscillations. Direct banded matrix solvers are used to solve the matrix systems of 2-D
problems. A block-iterative ORTHOMIN solver is used to solve 3-D problems. All boundary conditions can
be chosen constant in time or variable in time with either continuous or stepwise changes.
MAGICS has been verified for a variety of problems by comparison of its numerical solutions with available
analytical solutions and documented numerical results from several other codes including HYDRUS, VAM2D,
VAM3D, SWANFLOW, and NAPL3D. MAGICS is a robust code designed to solve highly nonlinear field
problems involving large contrasts in soil properties and highly nonlinear situations involving sharp saturation
fronts, and to provide accurate mass balance calculations.
Contact Address: HydroGeologic Inc., 1165 Herndon Parkway, # 900, Herndon, VA 22070
1-1-6
-------
Appendix I: Models for Multiphase Flow, Part 2: Usability and Reliability
IGWMC
Key
4420
4650
5180
5181
5184
5185
5189
5280
5281
5681
5820
5821
Model
GASOLINE
SWANFLOW
MOFAT
SPILLVOL
ARMOS
MOTRANS
SPILLCAD
KOPT
KROPT
VIP
MAGNAS
MAGICS
Usability
o
U
O
a
a
N
Y
U
Y
Y
Y
Y
U
U
Y
U
Y
O
10
s
o
8
a.
N
Y
U
Y
Y
Y
Y
U
U
Y
U
Y
«
o
U
I
—
ID
«
(0
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
C
O
•§
a
"Q.
a
M
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
U
-8
C
V
a.
O
o
a
5
•D
a
N
Y
Y
Y
Y
Y
Y
U
U
Y
U
Y
r
o
O.
U)
N
Y
Y
Y
Y
Y
Y
U
U
Y
U
Y
Reliability
^
o
o
-C
•a
I
o
•>
o
(C
h.
1
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
01
=5
o
U
•D
1
.s
o
tc.
o
a
U
U
U
U
U
U
U
U
U
U
U
U
•o
a
>
L
L
L
L
L
L
L
U
U
L
U
L
•a
a
H
~s
iZ
U
U
U
U
U
U
U
U
U
U
U
U
2
a>
3
U
F
F
M
M
M
M
U
U
F
U
U
KEY: Y = YES N = NO L = LIMITED E = EXTENSIVE M = MANY F = FEW U = UNKNOWN
1-2-1
-------
Appendix J: Cross-Reference Table for Appendices A through I
Model
_
—
—
—
—
—
—
—
—
2-D Finite Element Galerkin Model
2-D Steady State FE Model
3-D Free Surface FE Model
3-D FE DUAL POROSITY
3-D FRACTURE GENERATOR
3D-MADPD
3DFEMWATER
AIR
ANALYTICAL MODELS
AQ/BASIC GWF
AQ series
AQ-AT
AQ-EF
AQ-FEM
AQMAN
AQMODEL
AQTESOLV
AQU-1
AQUA
AQUA
AQUAMOD
AQUIFEM
AQUIFEM-1/AQUIFEM-N
AQUIFER
AQUIFLOW
AQUITRAN
AQUIX
AQUIX-T/AQUIX-4
ARMOS
ASM
ASM
AT123D
BALANCE
BEAVERSOFT
BEAVERSOFT
IGWMC
Key
5400
5401
5410
5411
5420
5430
5440
5441
5450
3881
5810
5560
5022
5320
5650
3377
6605
5100
6030
4752/54
4751
4754
4753
3092
5710
6670
1230
5018
5018
5730
514
2630
5110
3372
3378
6681
6681
5184
6603
6603
6120
3400
6590
6590
Appendix
/page
E-1-2
E-1-2
E-1-2
E-1-2
E-1-3
E-1-3
E-1-3
E-1-3
E-1-4
A.2-1-7
A.2-1-14
A.3-1-4
F-1-7
F-1-8
C.3-1-7
B.1-1-4
E-1-5
A.1-1-4
A.2-1-14
A.6-1-4
A.4-1-1
A.2-1-9
A.2-1-9
H-1-1
A. 1-1 -7
A.4-1-7
A.2-1-2
D-1-11
C.2-1-8
A.2-1-13
A.2-1-1
A.2-1-4
A.2-1-11
A.2-1-6
C.2-1-4
A.1-1-10
A.4-1-7
1-1-2
A.6-1-7
C.2-1-11
C.1-1-8
G-1-2
C.1-1-10
A.1-1-9
J-1
-------
Appendix J (continued)
Model
BEAVERSOFT
BIM/FRACGEN
BIO1D
BIOPLUME II
BIOSOIL
BLOB3D
BORHOL
CADIL7AGTEHM
CANSAZ (ERA-CMS)
CATTI
CFEMTRAN
CFEST
CFEST
CFITIM
CGAQUFEM
CHAIN
CHARGR
CHEMFLO
CHEMRANK
CHEMTRN/THCC
CHMTRNS
CHNTRNS
CHNTRNS
CHNTRNS
CHROMAT
CMIS
CMLS
CONFLOW
CONFLOW
CRACK
CRACK
CRAFLUSH
CREAMS
CRREL
CSUFDM
CSUGAS
CSUPAW
CTRAN/W
CTSPAC
CTSPAC
CUMOC/MIKERN
CXPMPM
CXTFIT
CXTFIT
DELPET
IGWMC
Key
6590
6810
5500
4910
5021
5242
696
4290
5330
6600
5244
2070
2070
6227
5240
6225
2761
6712
6640
3610
3611
3084
3084
3084
6701
6710
6711
2770
2770
6660
6660
5243
3540
2791
5392
5390
5391
5340
5031
5031
6770
5211
3432
3432
2061
Appendix
/page
A.6-1-7
F-1-9
C.4-1-11
C.2-1-7
C.4-1-8
C.1-1-5
D-1-2
C.4-1-5
C.2-1-9
C.1-1-10
C.2-1-9
C.3-1-2
D-1-3
C.1-1-8
A.2-1-12
C.4-1-14
D-1-5
C.4-1-16
C.4-1-15
C.2-1-4
G-1-2
G-1-2
D-1-6
C.2-1-3
G-1-7
C.4-1-15
C.4-1-15
A.1-1-2
A.6-1-2
F-1-9
C.1-1-11
C.1-1-5
C.4-1-3
A.1-1-2
A.2-1-12
E-1-1
A.1-1-6
A.6-1-6
D-1-12
C.4-1-9
C.2-1-11
C.1-1-4
C.1-1-2
C.4-1-3
H-1-1
J-2
-------
Appendix J (continued)
Model
DELTA
DELTIS
DFT/C-1D
DIFFMOD
DISIFLAQ
DISPEQ/DISPER/PISTON
DREAM
DSTRAM
DSTRAM
DYNAMIX
DYNFLOW
DYNTRACK
EPA-VHS
EQ3/EQ6
EQUILIB
FASTCHEM
FE3DGW
FE3DGW
FEM301
FEMA
FEMSAT
FEMSEEP
FEMTRAN
FEMWASTE/FECWASTE
FEMWATER/FECWATER
FEWA
FIELD-2D
FINITE
FLAME
FLAMINGO
FLASH
FLO
FLOFIT
FLONET
FLONETS
FLOP series
FLOP/FLOP-LIESTE/FLOP-Z1/FLOP-ZN
FLOSA
FLOSA
FLOTRA
FLOTRA
FLOWNET
FLOWNET
FLOWNS
FLOWNS
IGWMC
Key
260
2060
3860
5027
2870
3450/ 3451
4670
4700
4700
124
4990
4941
6601
4810
4820
5840
2072
2072
3450
3376
3350
5120
4350
3371
3370
3373
3861
5130
5661
4630
5660
1092
5187
4922
5241
1820
1820
4660
4660
3235
3235
5001
5001
5200
5200
Appendix
/page
H-1-1
H-1-1
D-1-9
D-1-11
A.2-1-5
C.4-1-3
A. 1-1 -3
D-1-11
C.3-1-5
G-1-1
A.3-1-4
C.3-1-5
C.1-1-11
G-1-3
G-1-3
G-1-7
A.3-1-1
A.6-1-2
A.3-1-3
C.2-1-4
A.2-1-6
C.2-1-8
C.4-1-5
C.4-1-2
B. 1-1-4
A.2-1-7
D-1-9
A.1-1-4
C.4-1-11
C.4-1-6
F-1-8
B. 1-1-2
B. 2-1-1
A.6-1-5
A.2-1-12
A.6-1-1
A.1-1-1
A.6-1-4
A.3-1-4
C.4-1-2
D-1-7
A.2-1-10
A.6-1-5
A.6-1-6
A.2-1-11
J-3
-------
Appendix J (continued)
Model
FLOWPATH
FLOWPATH
FLOWVEC
FLSTAT
FLUMP
FOWL
FP
FRACFLOW
FRACFLOW
FRACPORT
FRACQUAL
FRACSOL
FRACTEST
FRANET
FRESAL
FRONT
FRONT
FTRANS
FTRANS
FTWORK
GAFETTA
GASOLINE
GEOCHEM
GEOFLOW
GEOFLOW
GEOTHER
GEOTRACK
GETOUT
GGWP
GLEAMS
GLOVER
GM5
GRDFLX
GREASE
GREASE
GREASE
GRNDFLO
GROUND
GROUND WATER DISCHARGE TESTS
GRWATER
GS2
GS3
GTC
GW-UN/DTCD
GWAP
IGWMC
Key
4920
4920
4390
5570
122
5033
6170
3232
3232
3374
5174
2037
4470
5680
5540
1822
1822
581
581
5520
513
4420
4830
3220
5230
730
5501
2080
1010
3541
5140
3240
3380
582
582
582
3190
6100
5460
3660
2891
2892
5028
4730
5040
Appendix
/page
A.6-1-5
A.2-1-10
B.1-1-5
A.1-1-6
B.1-1-2
G-1-7
B.2-1-2
F-1-3
D-1-6
F-1-4
C.1-1-4
C.1-1-1
F-1-6
F-1-9
A.2-1-13
A.1-1-1
A.6-1-1
F-1-1
D-1-1
C.3-1-6
D-1-1
1-1-1
G-1-4
C.2-1-3
A.2-1-12
D-1-3
A.6-1-6
C.1-1-1
C.2-1-2
C.4-1-3
A.1-1-5
A.2-1-6
C.1-1-1
C.3-1-1
D-1-2
F-1-1
H-1-2
C.1-1-7
A.4-1-5
B.1-1-5
C.4-1-1
C.4-1-1
C.4-1-9
A. 1-1 -3
A.4-1-2
J-4
-------
Appendix J (continued)
Model
GWFL3D
GWFLOW/GWMESH/GWPLOT
GWFLOW
GWHEAD
GWMAN
GWPATH
GWPATH
GWPT
GWSIM
GWSIM-II
GWTHERM
GWTR3D
GWUSER/CONJUN
HJ-MATCH
HOTWTR
HPATCH3D
HSSWDS
HST3D
HST3D
HVRLV 1
HWELL
HYDROPAL
HYDRUS/WORM
HYPER-VENTILATE
ICE-1
IMAGEW-1
INFGR
INFIL
INTERFACE
INTERSAT
INTERTRANS
IONMIG
ISOQUAD
JDB2D/3D
KOPT
KROPT
LANDFIL
LAYFLO
LEACHM(-P)
LEAKY
LINE2D
LTIRD
MADPD
MAF
MAGICS
IGWMC
Key
6353
3101
6023
2880
4480
6650
6650
6352
681
680
2830
6354
4070
5050
612
5245
4410
4610
4610
3150
6383
5150
6229
5940
6602
683
4380
3570
2720
5160
5161
4360
510
5720
5280
5281
4400
4082
3411
5131
5246
6310
5270
5790
5821
Appendix
/page
A.2-1-15
A.2-1-5
A.1-1-8
A.3-1-2
H-1-3
A.6-1-8
A.2-1-15
A.1-1-8
A.2-1-1
C.2-1-1
D-1-5
C.2-1-1 1
H-1-2
A.4-1-2
D-1-2
C.1-1-5
B.1-1-6
C.3-1-4
D-1-11
A.4-1-1
A. 1-1 -9
A. 1-1 -5
C.4-1-14
E-1-5
D-1-12
A.1-1-1
B.1-1-5
B.1-1-4
A.2-1-4
A.2-1-11
C.3-1-6
C.2-1-6
A.3-1-1
A.2-1-1 3
1-1-5
1-1-5
B.1-1-5
C.1-1-2
C.4-1-2
A.1-1-4
C.1-1-6
C.1-1-9
C.2-1-9
A.1-1-7
E-1-4
J-5
-------
Appendix J (continued)
Model
MAGICS
MAGNAS
MAGNUM-2D
MAGNUM-2D
MAGNUM-3D
MAQWF
MARIAH
MASCOT
MASS
MAST-2D
MATE
MATTUM
MFLOP
MFLOP
MICROFEM
MINEQL2
MININR/MINICUP
MINTEQ/MINTEQ2/MINTEQA2
MLSOIL/DFSOIL
MLU
MLU
MLU
MOCDENSE
MODFE
MODFLOW
MODFLOWP
MODINV
MODMAN
MODMOC-3D
MODPATH
MOFAT
MOFAT
MOTIF
MOTIF
MOTRANS
MOTRANS
MOUSE
MT3D
MULKOM
MULKOM
MULTIMED
MUSHRM
MUST
MYGRT
NEFTRAN
IGWMC
Key
5821
5820
4590
4590
4591
4530
2620
4620
5732
3868
5002
3375
5004
5004
5000
4840
4851
4850
4140
5003
5003
5003
742
4100
3980
3987
3981
3983
5800
3984
5180
5180
4550
4550
5185
5185
6390
4970
2581
2581
5630
2760
1771
6700
5025
Appendix
/page
1-1-6
1-1-6
D-1-10
F-1-6
A.6-1-4
A.2-1-8
D-1-4
C.1-1-2
C.2-1-10
C.2-1-5
A.4-1-1
D-1-7
A.6-1-5
A. 1-1 -4
A.2-1-10
G-1-4
G-1-4
G-1-4
C.4-1-4
A.4-1-2
A. 1-1 -3
F-1-7
C.2-1-2
A.2-1-8
A.3-1-3
A.5-1-1
A.5-1-1
H-1-2
C.3-1-7
A.6-1-3
E-1-1
1-1-1
D-1-10
F-1-6
1-1-3
E-1-1
C.4-1-14
C.3-1-6
D-1-4
F-1-3
C.4-1-11
D-1-5
B.1-1-2
C.1-1-11
F-1-7
J-6
-------
Appendix J (continued)
Model
NETFLO
NETFLO/ NETRANS
NETPATH
NEWTMC
NITRO
NMFD-3D
NON-LINEAR FE/FD REGRESSION
NUSEEP
OASIS
OASIS
ODAST
ONE-D
ONESTEP
OPTIC
OPTP/PTEST
PAPADOP
PAT
PAT
PATCH3D
PATH3D
PATH3D
PATHRAE
PATHS
PATHS
PATHS
PC-SEEP
PESTAN
PETROS
PHREEQE
PHRQPITZ
PLASM
PLUME
PLUME
PLUME2D
POLLUT
PORFLO
PORFLO
PORFLO
PORFLOW-3D
PORFLOW-3D
PORFLOW-3D
PORFLOW-II
PORFLOW-II
PORFREEZE
PORSTAT/ PORMC
IGWMC
Key
695
5640
3621
5860
5186
2740
195
5030
4911
4911
6312
6220
3433
6703
6570
5051
6604
6604
5247
3982
3982
5024
2120
2120
2120
4980
6130
5490
2610
2611
322
5055
6020
6024
5175
3790
3790
3790
3238
3238
3238
3233
3233
3236
3237
Appendix
/page
F-1-2
F-1-8
G-1-3
C.4-1-13
C.4-1-9
A.3-1-2
A.5-1-1
A.2-1-11
C.1-1-3
C.2-1-7
C.1-1-9
C.1-1-8
B.2-1-1
H-1-3
A.1-1-9
A.4-1-2
A.1-1-9
A.6-1-8
C.1-1-6
A.3-1-3
A.6-1-3
C.1-1-3
C.2-1-2
A. 1-1 -2
A.6-1-2
B.1-1-6
C.4-1-13
E-1-4
G-1-1
G-1-1
A.2-1-1
C.1-1-3
C.1-1-7
C.1-1-7
C.1-1-4
C.2-1-5
D-1-8
F-1-4
D-1-7
F-1-4
C.4-1-2
C.2-1-4
D-1-6
D-1-7
A.2-1-5
J-7
-------
Appendix J (continued)
Model
POSSM/MCPOSSM
PROTOCOL
PRZM
PRZMAL
PRZMAL
PT/CCC
PT
PTC
PTDPS II
PTDPS III
PTDPS 1
PULSE
PUMP
PUMPING TEST PACKAGE
PUMPING TEST PROGRAM
PUMPTEST
Quasi-3-D Multiaquifer Model
QUICKFLOW
QUICKFLOW
RAND3D
RANDOM WALK/TRANS
RAQSIM
REDEQL-EPA
REDEQL-UMD
RESSQ
RESSQ
RESSQ
RETC
RITZ
ROCMAS-THM
ROCMAS-THM
RUSTIC
RWH
RZWQM
SAFTAP
SAFTAP
SAFTMOD
SANDWICH
SANGRE
SANGRE
SATEM
SATRA-CHEM
SATURN
SBIR
SCHAFF
IGWMC
Key
5780
4860
4720
5310
5310
100
3890
515
5061
5062
5060
5210
5080
5190
5070
6382
2510
5300
5300
2691
2690
4640
4870
4871
3940
3940
3940
6228
6620
3083
3083
4721
6011
5850
5822
5822
4694
5530
4600
4600
2801
3831
583
4391
160
Appendix
/page
C.2-1-10
G-1-5
C.4-1-7
C.4-1-10
C.1-1-6
D-1-1
D-1-9
C.3-1-1
A.4-1-3
A.4-1-4
A.4-1-3
C.1-1-4
A.4-1-4
A.4-1-5
A.4-1-4
A.4-1-6
A.2-1-3
A.1-1-6
A.6-1-6
C.3-1-2
C.2-1-3
A.2-1-9
G-1-5
G-1-5
A. 1-1 -2
A.6-1-3
C.2-1-5
B.2-1-3
C.4-1-15
F-1-3
D-1-6
C.4-1-8
C.1-1-7
C.4-1-13
C.3-1-8
A.6-1-7
C.2-1-7
C.2-1-9
D-1-10
F-1-6
A.4-1-1
C.2-1-5
C.4-1-1
C.4-1-5
D-1-1
J-8
-------
Appendix J (continued)
Model
Seawater Intrusion with BIEM
SEAWTR/SEACONF
SEEP(VM)-3D
SEEPV
SEFTRAN
SEFTRAN
SEFTRAN
SENECA
SESOIL
SGMP
SHAFT
SHALT
SHALT
SHARP
SIMGRO
SLAEM/SLW/SLWL/SYLENS
SLAEM/SLW/SLWL/SYLENS
SLAM
SLUGIX/AQUIX-S
SOHYP
SOIL
SOILMOP
SOILPROP
SOLMNEQ/SOLMNEQF
SOLMNQ
SOLUTE
SOMINEQ.88
SOMOF
SOTRAN
SPILLCAD
SPILLVOL
SPLASHWATER
SSIM3D
ST2D
STAFAN
STAFF2D
STEP-MATCH
STLINE
STLINE
STREAMLINE
SUPER1D
SURMF
SUTRA
SUTRA
SVE COLUMN
IGWMC
Key
3241
3640
3863
2890
588
588
588
4990
5039
2800
2580
2034
2034
5750
5010
1791
1791
4900
6680
6226
6330
2062
5183
4880
4881
6380
4882
2983
4320
5189
5181
3590
772
4160
584
4710
5052
5600
5600
5176
5248
4740
3830
3830
5950
Appendix
/page
A.2-1-6
A.2-1-7
A.3-1-2
B.1-1-3
D-1-2
F-1-2
C.2-1-1
G-1-7
C.4-1-9
A.2-1-5
D-1-4
F-1-2
D-1-3
A.2-1-14
B.1-1-6
A.1-1-1
A.6-1-1
A.2-1-9
A.4-1-7
B.2-1-2
B.2-1-3
B.1-1-3
B.2-1-1
G-1-5
G-1-6
C.1-1-10
G-1-6
B.1-1-3
C.2-1-6
1-1-4
1-1-2
D-1-8
A.2-1-2
A.2-1-8
F-1-1
F-1-7
A.4-1-3
A.6-1-7
A.3-1-5
A.1-1-5
C.1-1-6
C.1-1-2
D-1-8
C.4-1-4
E-1-5
J-9
-------
Appendix J (continued)
Model
SWACROP
SWANFLOW
SWENT
SWENT
SWICHA
SWIFT
SWIFT HI/386
SWIFT II
SWIFT II
SWIFT
SWIFT 111/386
SWIFT
SWIFT lll/SWIFT-386
SWIGS2D
SWIM
SWIP/SWI PR/DWDM
SWSOR
TARGET-2DH
TARGET-2DM
TARGET-2DU
TARGET-3DS
TARGET-SOU
TDAST
TDF1O
TDFD10
TDPLUME/ TWOPLME
TENSOR2D
TEXASHEAT
TGUESS
THCVFIT
THEIS
THEIS2
THEISFIT
THWELLS
TIM1/TIM2
TIMELAG
TOUGH
TOUGH
TRACR3D
TRACR3D
TRAFRAP
TRANQL/MICROQL
TRANQL/MICROQL
TRANS
TRIAG
IGWMC
Key
2550
4650
697
697
4631
1852
3842
3841
3841
3840
3842
3840
3842
3600
2631
692
2140
4930
4932
4931
4933
4934
6311
5213
5213
5212
6730
3970
6450
6025
5171
5172
6080
6022
5920
6580
2582
2582
4270
4270
589
4450
4450
2950
2640
Appendix
/page
B.1-1-3
1-1-1
D-1-3
C.3-1-2
C.3-1-4
A.2-1-2
F-1-4
C.3-1-3
D-1-8
D-1-8
D-1-9
C.3-1-2
C.3-1-3
A.2-1-7
A.2-1-4
C.3-1-1
A.2-1-3
C.2-1-7
C.2-1-8
C.4-1-8
C.3-1-5
C.4-1-8
C.1-1-9
C.4-1-10
D-1-12
C.1-1-5
A.4-1-8
D-1-10
A.4-1-6
A.4-1-5
A.1-1-5
A. 1-1 -5
A.4-1-5
A. 1-1 -7
A.1-1-7
A.4-1-7
F-1-3
D-1-4
F-1-5
C.4-1-5
F-1-2
G-1-3
C.2-1-6
D-1-5
A.2-1-4
J-10
-------
Appendix J (continued)
Model
TRIPM
TRUCHN/ZONE
TRUMP
TRUST
TS-MATCH
TSSLEAK
TWODIMPL
UNSAT
UNSAT-1
UNSAT-H
UNSAT1D
UNSAT2
UNSTEADY FLOW
USGS FRONT-TRACKING
USGS FRONT-TRACKING
USGS-2D-FLOW
USGS-2D-TRANSPORT/MOC/KONBRED
USGS-3D-FLOW
UWIS-2D-TRANSPORT
VADOFT
VADOSE
VADOSE
VADOSE
VAM2D
VAM3D
Variable Density Model
VARQ
VENTING
VIP
VIP
VLEACH
VS2DA/S2DT
VSAFT2
VTT
VTT
VTTSS2
VTTSS3
WALTON35
WALTON35
WASTE
WATEQ2/WATEQ4F
WATEQ3
WATEQF
WATERFLO
WATSUP
IGWMC
Key
4081
4031
4030
120
5054
6081
5861
6400
3431
4340
2071
21
4901
741
741
771
740
770
2860
4693
3234
3234
5057
4690
4691
2663
6082
5182
5681
5681
5690
4570
5220
2092
2092
2091
2090
6350
6350
2810
4890
4891
3620
6630
3191
Appendix
/page
C.4-1-4
F-1-5
D-1-10
B.1-1-1
A.4-1-3
A.4-1-6
C.2-1-10
B.1-1-7
B.1-1-4
B.1-1-5
B.1-1-2
B.1-1-1
A.2-1-10
A.2-1-1
A.6-1-1
A.2-1-2
C.2-1-1
A.3-1-1
D-1-5
C.4-1-7
D-1-7
C.4-1-1
B.1-1-7
C.4-1-6
C.4-1-7
A.3-1-2
A.4-1-6
E-1-1
1-1-5
C.4-1-1 2
C.4-1-1 2
C.4-1-5
C.4-1-10
A.2-1-3
A.6-1-2
A.2-1-3
A.3-1-1
C.1-1-9
A. 1-1 -8
C.1-1-1
G-1-6
G-1-6
G-1-2
B.1-1-7
H-1-2
J-11
-------
Appendix J (continued)
Model IGWMC Appendix
Key /page
WELFUN/WELFLO/CONMIG 6351 C.1-1-10
WELFUN/WELLFLO/CONMIG 6351 A.1-1-8
WELL 6250 C.1-1-8
WHIP 5090 A.4-1-4
WHPA 3943 A.6-1-3
WHPA 3943 A. 1-1-3
WTQUAL1 251 C.2-1-1
J-12
flU.S. GOVERNMENT PRINTING OFFICE: 1994 - 550-001/80404
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