EPA
                                               August  1990
A SUBTITLE D LANDFILL APPLICATION MANUAL
       FOR THE  MULTIMEDIA EXPOSURE
       ASSESSMENT MODEL (MULTIMED)
                   by
           Susan Sharp-Hansen1
           Constance Travers1
               Paul Hummel1
             Terry Allison2

         AQUA TERRA Consultants1
         Mountain View,  CA 94043

     Computer  Sciences  Corporation2
         Athens, GA  30605-2720
       EPA Contract  No.  68-03-3513
             Project  Monitor

              Gerard  Laniak
    Environmental  Research Laboratory
  U.S. Environmental Protection Agency
         Athens, GA  30605-2720
    ENVIRONMENTAL RESEARCH LABORATORY
   OFFICE OF RESEARCH AND DEVELOPMENT
  U.S. ENVIRONMENTAL PROTECTION AGENCY
       ATHENS,  GEORGIA  30605-2720

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                                  DISCLAIMER


The work presented in this document has been funded by the United States
Environmental Protection Agency.  It has been subject to the Agency's peer and
administrative review,  and has been approved as an EPA document.   Mention of
trade names or commercial products does not constitute endorsement or
recommendation for use by the U.S. Environmental Protection Agency.

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                                   FOREWORD


As environmental controls become more costly to implement and the penalties of
judgment errors become more severe, environmental quality management requires
more efficient management tools based on greater knowledge of the
environmental phenomena to be managed.  As part of this Laboratory's research
on the occurrence,  movement, transformation, impact and control of
environmental contaminants, the Assessment Branch develops management or
engineering tools to help pollution control officials assess the risk to human
health and the environment posed by land disposal of hazardous wastes.

EPA's Multimedia Exposure Assessment  (MULTIMED) simulates the transport and
transformation of contaminants released from a hazardous waste disposal
facility into the multimedia environment.   MULTIMED includes contaminant
release to either air or soil and possible interception of the subsurface
plume by a surface stream.  An important application of MULTIMED would be the
prediction of pollutant movement in leachate from a Subtitle D landfill, a use
that requires only a subset of the model's full capabilities.  This manual,
then, provides instruction for inexperienced as well as experienced model
users who seek to study or design waste disposal facilities.

                                          Rosemarie C. Russo, Ph.D.
                                          Director
                                          Environmental Research Laboratory
                                          Athens, GA

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                                   ABSTRACT


The Environmental Protection Agency's Multimedia Exposure Assessment Model
(MULTIMED)  for exposure assessment simulates the movement of contaminants
leaching from a landfill.  The model consists of a number of modules which
predict concentrations at a receptor due to transport in the subsurface,
surface water, or air.  This report is an application manual for the use of
MULTIMED in modeling Subtitle D land disposal facilities.

when applying MULTIMED to Subtitle D facilities, the landfill,  surface water,
and air modules in the model are not accessible by the user; only flow and
transport through the unsaturated zone and transport in saturated zone can be
considered.  A steady-state, one-dimensional, semi-analytical module simulates
flow in the unsaturated zone.  The output from this module,  water saturation
as a function of depth, is used as input to the unsaturated zone transport
module.  The latter simulates transient, one-dimensional (vertical)  transport
in the unsaturated zone and includes the effects of longitudinal dispersion,
linear adsorption, and first-order decay.  The unsaturated zone transport
module calculates steady-state or transient contaminant concentrations.
Output from both unsaturated zone modules is used to couple the unsaturated
zone transport module with the steady-state or transient, semi-analytical
saturated zone transport module.  The latter includes one-dimensional uniform
flow,  three-dimensional dispersion, linear adsorption, first-order decay, and
dilution due to direct infiltration into the groundwater plume.

The fate of contaminants in the various media depends on the chemical
properties of the contaminants as well as a number of media- and environment-
specific parameters.  The uncertainty in these parameters can be quantified in
MULTIMED using the Monte Carlo simulation technique.

To enhance the user-friendly nature of MULTIMED, a preprocessor, PREMED, and a
postprocessor, POSTMED, have been developed.  The preprocessor guides the user
in the creation of a correct Subtitle D input file by restricting certain
options and parameters and by setting appropriate defaults.

This report was submitted in partial fulfillment of Work Assignment Number 32,
Contract Number 68-03-3513 by AQUA TERRA Consultants, under the sponsorship of
the U.S. Environmental Protection Agency.  This report covers the period March
1990 to July 1990, and work was completed as of August 1990.

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                               TABLE  OF  CONTENTS
Section
Disclaimer	    ii
Foreword	   iii
Abstract	    iv
Figures	    ix
Tables	   xii
Acknowledgements	   xvi

1 . 0   INTRODUCTION	     1
      1.1   Overview of MULTIMED	     1
            1.1.1   Model Capabilities	     1
            1.1.2   Interaction Framework (AIDE)	     3
      1.2   Application of MULTIMED to Subtitle D Land Disposal
            Facilities	     3
      1.3   Report Organization	     4
      1.4   How to Use this Manual	     4

2 . 0   PROGRAM INSTALLATION AND EXECUTION	     7
      2.1   System Requirements	     7
            2.1.1   Hardware	     7
            2.1.2   Software	     7
      2.2   Loading the Executable Code	     7
      2.3   Executing and Verifying Test Sessions	     8

3 . 0   FORMAT AND OPERATION OF THE PRE- AND POSTPROCESSOR	    10
      3.1   Screen Format	    10
            3.1.1   Data window	    10
            3.1.2   Assistance Window	    12
            3.1.3   Instruction Window	    16
            3.1.4   Command Line	    16
      3.2   Interaction Modes	    17
      3.3   Screen Movement	    19
            3.3.1   Movement within Screens	    19
            3.3.2   Movement between Screens	    21
            3.3.3   Screen Path	    21

4 . 0   USE OF THE PRE- AND POSTPROCESSORS	    23
      4.1   The Preprocessor (PREMED)	    23
            4.1.1   Use of the Preprocessor	    23
            4.1.2   The PREMED Tutorials	    38
      4.2   The Postprocessor  (POSTMED)	    39
            4.2.1   Use of the Postprocessor	    39

5 . 0   MODEL APPLICATION	    46
      5 .1   MULTIMED Capabilities and Limitations	    47
            5.1.1   Solution Techniques	    47
            5.1.2   Spatial Characteristics of the System	    49
            5.1.3   Steady-state Versus Transient Flow and Transport..    50
            5.1.4   Monte Carlo Versus Deterministic Simulations	    51
            5.1.5   Boundary Conditions	    52
      5.2   Subtitle D Applications of MULTIMED	    52
            5.2.1   Summary of EPA Requirements for MULTIMED
                    Simulations of Leachate Migration from Subtitle D
                    Facilities	    52
            5.2.2   Active Modules	    53

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            5.2.3   Boundary Conditions	     53
            5.2.4   Procedures for Application of MULTIMED to
                    Subtitle D Facility Design	     53
      5.3   MULTIMED Input Requirements	     56
            5.3.1   Parameter Requirements Summarized by Module	     57
            5.3.2   Parameter Requirements Summarized by Data Group...     57

6 . 0   PARAMETER ESTIMATION	     77
      6.1   Chemical-Specific Parameters	     78
            6.1.1   Overall Chemical Decay Coefficient (Saturated
                    Zone)	     78
            6.1.2   Solid-Phase and Liquid-Phase Decay Coefficients
                    (Saturated Zone)	     78
            6.1.3   The Acid-Catalyzed and Base-Catalyzed Hydrolysis
                    Rates  and the Neutral Hydrolysis Rate	     78
            6.1.4   Reference Temperature	     79
            6.1.5   Distribution Coefficient (Saturated Zone)	     79
            6.1.6   Normalized Organic Carbon Distribution
                    Coefficient	     79
            6.1.7   Biodegradation Coefficient (Saturated Zone)	     80
      6.2   Source-Specific Parameters	     80
            6.2.1   Recharge Rate	     80
            6.2.2   Infiltration Rate	     80
            6.2.3   Area of the Waste Disposal Unit	     81
            6.2.4   Length Scale of the Facility	     81
            6.2.5   width  Scale of the Facility	     81
            6.2.6   Initial Concentration at Waste Disposal Facility..     81
            6.2.7   Source Decay Constant	     81
            6.2.8   Duration of Pulse	     82
            6.2.9   Spread of Contaminant Source	     82
      6.3   Unsaturated Flow Parameters	     82
            6.3.1   Saturated Hydraulic Conductivity	     82
            6.3.2   Unsaturated Zone Porosity	     84
            6.3.3   Air Entry Pressure Head	     85
            6.3.4   Number of Layers,  Thickness of Layers	     85
            6.3.5   Residual Water Content	     86
            6.3.6   Brooks and Corey Exponent	     86
            6.3.7   Van Genuchten Parameters	     86

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      6 . 4
            Unsaturated Transport Parameters
            6.4.1   Number of Layers ,  Thickness of Layers
            6.4.2   Longitudinal Dispersivity of Each Layer
            6.4.3   Percent Organic Matter
            6.4.4   Bulk Density of Soil for Layer
            6.4.5   Biological Decay Coefficient
      6 . 5   Aquifer-Specific Parameters
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
.5.
. 5 .
.5.
. 5 .
.5.
. 5 .
.5.
. 5 .
.5.
. 5 .
. 1
.2
.3
.4
.5
.6
. 7
.8
.9
.10
             .5.11
             .5.12
             . 5 . 13
             .5.14
                    Aquifer Porosity
                    Particle Diameter ..............................
                    Bulk Density ...................................
                    Aquifer Thickness ..............................
                    Source Thickness (Mixing Zone Depth) ...........
                    Hydraulic Conductivity .........................
                    Hydraulic Gradient .............................
                    Groundwater Seepage Velocity ...................
                    Retardation Coefficient ........................
                    Longitudinal,  Transverse, and Vertical
                    Dispersivities .................................
                    Aquifer Temperature ............................
                    pH .............................................
                    Organic Carbon Content (Fraction) ..............
                    Well Distance from Site,  Angle off Center, and
                    Well Vertical Distance .........................
                                                                    87
                                                                    87
                                                                    89
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                                                                    92
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                                                                    95
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                                                                    99
                                                                    99
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                                                                   100
                                                                   103
                                                                   103
                                                                   103

                                                                   103
7.0
EXAMPLE PROBLEMS	
7 .1   Example 1	
      7.1.1   The Hypothetical Scenario.
      7.1.2   Input	
      7.1.3   Output	
7.2   Example 2	
      7.2.1   The Hypothetical Scenario.
              Input	
              Output	
            7.2.2
            7.2.3
      7.3   Example 3	
            7.3.1   The Hypothetical Scenario.
            7.3.2   Input	
            7.3.3   Output	
      REFERENCES.
                                                                         106
                                                                         106
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                                                                         107
                                                                         110
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                                                                         124
                                                                         124
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                                                                         129

                                                                         142
APPENDIX A - CODE STRUCTURE AND INPUT DATA FORMAT..
      A.1   Model Structure	
      A.2   Input and Output File Units	
      A.3   Common Blocks and Parameter Statements.
      A.4   Structure of the Input Files	
            A. 4 .1
            A. 4 .2
            A. 4 .3
            A. 4 .4
            A. 4 . 5
              Comment Cards.
              Data Group/Subgroup Specification Card, End Card
              and Data Cards	
              Specification of Parameter Values	
              The Array Subgroup	
              The Empirical Distribution Subgroup	
                                                                         148
                                                                         148
                                                                         148
                                                                         151
                                                                         154
                                                                         154

                                                                         154
                                                                         156
                                                                         157
                                                                         159

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      A. 5   Format of the Data Groups	   159
            A. 5.1   General Data Group	   159
            A. 5. 2   Source Data Group	   159
            A.5.3   Landfill Data Group	   163
            A. 5 . 4   Chemical Data Group	   168
            A. 5. 5   Unsaturated Flow Data Group	   170
            A. 5 . 6   Unsaturated Transport Data Group	   184
            A. 5. 7   Aquifer Data Group	   186
            A. 5. 8   Surface Water Data Group	   189
            A. 5. 9   Air Emissions and Dispersion Data Group	   191

APPENDIX B - SUBROUTINES IN MULTIMED	   201

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                                   FIGURES



2.1   Preprocessor screen after installation	      8

3 .1   Screen format utilized by the pre- and postprocessor	     11

3.2   Example of a two window,  one command line screen	    12

3.3   Example of a three window,  one command line screen	    13

3.4   Example of a HELP assistance window	     14

3 . 5   Example of a LIMITS assistance window	     15

3.6   Example of information contained in a STATUS assistance window..     16

3.7   Example of an ERROR message in the instruction window	     17

4 .1   Opening screen of the preprocessor	     23

4.2   Build/Modify screen of the preprocessor	     24

4.3   Edit screen of the preprocessor	     25

4 . 4   Create screen of the preprocessor	     25

4 . 5   General-1 screen of the preprocessor	     26

4 . 6   General-2 screen of the preprocessor	     28

4 . 7   Edit screen of the preprocessor	     28

4 . 8   AQuifer screen of the preprocessor	     29

4 . 9   SOurce screen of the preprocessor	     30

4 .10  Chemical screen of preprocessor	     30

4.11  Unsaturated Flow (Funsat)  screen of the preprocessor	     31

4.12  Unsaturated Transport (Tunsat)  screen of the preprocessor	     31

4.13  The Depth screen of the preprocessor	     32

4.14  The POrosity screen of the preprocessor for a deterministic
      simulation	     34

4.15  Screen for specification of aquifer porosity for a
      deterministic simulation	     34

4.16  Porosity screen of the preprocessor for a Monte Carlo
      simulation	     35

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4.17  Screen showing required parameters for a Lognormal
      probability density distribution	     35

4 .18  The Return screen of the preprocessor	     37

4.19  The Save screen of the preprocessor	     37

4.20  Example of a tutorial screen	     38

4.21  Opening screen of the postprocessor	     40

4.22  Data-1 screen of the postprocessor	     41

4.23  Data-2 screen of the postprocessor	     41

4.24  Specs screen of the postprocessor	     43

4.25  Titles screen of the postprocessor	     43

4.26  Example of a cumulative frequency plot	     44

4.27  Example of a frequency plot	     44

4.28  Example of screen showing a TEXT file	     45

5.1   Procedure for using MULTIMED to assist in the design of
      Subtitle D facilities	     54

6.1   Schematic of the source thickness and the well location	     97

6.2   Measured values of longitudinal dispersivity as a function
      of path length over which dispersion is observed	    101

6.3   Average temperatures of shallow groundwater in the
      continental United States	    104

A. 1   Subroutine organization tree for MULTIMED	    149

A.2   Structure of the input data file,  data groups, and subgroups....    155

A.3   Key options available in the general data group pertaining to
      the saturated zone transport module	    164

A. 4   Key options available in the surface water module	    195

A. 5   Key options available in the air modules	    199

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                                    TABLES
3-1      Commands for Application of PREMED	    18

5-1      Issues to be Considered before Applying MULTIMED	    48

5-2      Primary Parameters Used in the Saturated Zone Transport
         Module for Subtitle D Applications of MULTIMED	    58

5-3      Parameters Used to Derive Other Saturated Zone Transport
         Module Parameters Needed in Subtitle D Applications of
         MULTIMED	    59

5-4      Parameters Required in the Unsaturated Zone Flow Module for
         Subtitle D Applications of MULTIMED	    61

5-5      Parameters Required in the Unsaturated Zone Transport
         Module for Subtitle D Applications of MULTIMED	    62

5-6      Parameters in the Chemical (Chemical) Data Group	    64

5-7      Parameters Required for Selected Probability Density
         Distributions	    67

5-8      Parameters in the Contaminant Source (SOurce) Data Group	    68

5-9      Parameters in the Aquifer (AQuifer)  Data Group	    69

5-10     Parameters in the Unsaturated Zone Flow (Funsat) Data Group..    72

5-11     Parameters in the Unsaturated Zone Transport (Tunsat)
         Data Group	    75

6-1      Range of Hydraulic Conductivity Values for Various

         Geologic Materials	    83

6-2      Descriptive Statistics for Saturated Hydraulic Conductivity..    84

6-3      Total Porosity of Various Materials	    85

6-4      Descriptive Statistics for Saturation Water Content and
         Residual Water Content	    87

6-5      Descriptive Statistics for van Genuchten Water Retention
         Model Parameters	    88

6-6      Compilation of Field Dispersivity Values	    90

6-7      Descriptive Statistics and Distribution Model for Organic
         Matter (Percent by Weight)	    91

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6-8
6-9
6-10
6-11

6-12 (a)

6-12 (b)

7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
7-10
7-11
A-l
A-2
A-3
A-4
A-5
A-6

A-7
A-8
A-9
A-10
A-ll

Mean Bulk Density for Five Soil Textural Classifications 	
Descriptive Statistics for Bulk Density 	
Range of Soil Particle Sizes for Various Materials 	
Range and Mean Values of Dry Bulk Density for Various
Geologic Materials 	
Alternatives for Including Dispersivities in the Saturated
Zone Module 	
Probabilistic Representation of Longitudinal Dispersivity
for a Distance of 152.4 m 	
Input Sequence for Example 1 	
Output File for Example 1 	
SAT . OUT File for Example 1 	
Input Sequence for Example 2 	
Main Output File for Example 2 	
SAT . OUT File for Example 2 	
Monte Carlo Distribution Values in Example 3 	
Input Sequence for Example 3 	
Main Output File for Example 3 	
First Page of the SAT 1. OUT File for Example 3 	
STATS . OUT File for Example 3 	
Input Files Needed in MULTIMED 	
Output Files Generated by MULTIMED 	
Input Data Groups and Subgroups in MULTIMED 	
Distributions Available and their Codes 	
Contents and Format of a Typical Array Subgroup 	
Contents and Format of a Typical Empirical Distribution
Subgroup 	
Contents and Format of the General Data Group 	
Example of a Typical General Data Group 	
Contents and Format of the Source-Specific Data Group 	
Variables in the Source-Specific Array Subgroup 	
Contents and Format of the Landfill Module Control Data
Group 	
93
94
95

96

102

102
108
111
114
115
119
123
124
125
130
140
141
151
152
156
157
158

160
161
165
166
167

169

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A-12     Contents and Format of the Landfill Module Layer
         Thickness and Material Data Subgroup	   170

A-13     Contents and Format of the Landfill Module Liner Property
         Subgroup	   171

A-14     Variables in the Landfill Liner Property Array Subgroup	   172

A-15     Contents and Format of the Landfill Module Material
         Property Subgroup	   173

A-16     Variables in the Landfill Material Property Array Subgroup...   174

A-17     Contents and Format of the Landfill Module Hydrology
         Subgroup	   175

A-18     Variables in the Landfill Hydrology Array Subgroup	   176

A-19     Contents and Format of the Chemical-Specific Data Group	   177

A-20     Variables in the Chemical Array Subgroup	   178

A-21     Contents and Format of the Unsaturated Zone Flow
         Module Control Data Group	   179

A-22     Contents and Format of the Unsaturated Flow Module Layer
         Thickness and Material Data Subgroup	   181

A-23     Contents and Format of the Unsaturated Zone Flow Module
         Material Property Subgroup	   182

A-24     Variables in the Unsaturated Flow Material Property Array
         Subgroup	   183

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A-25     Contents and Format of the Unsaturated Zone Flow Module
         Moisture Data Subgroup	   184

A-26     Variables in the Unsaturated Flow Moisture Data Array
         Subgroup	   185

A-27     Contents and Format of the Unsaturated Zone Transport
         Module Control Data Subgroup	   187

A-28     Contents and Format of the Unsaturated Zone Transport
         Module Properties Subgroup	   189

A-29     Variables in the Unsaturated Transport Properties Array
         Subgroup	   190

A-30     Contents and Format of the Aquifer-Specific Data Group	   191

A-31     Variables in the Aquifer Data Array Subgroup	   192

A-32     Contents and Format of the Surface Water Data Group	   193

A-33     Variables in the Surface Water Data Array Subgroup	   194

A-34     Contents and Format of the Air Emission and Dispersion
         Data Group	   196

A-35     Variables in the Air Emission and Dispersion Data Array
         Subgroup	   197

A-36     Contents and Format of the Air Dispersion Control Data
         Subgroup	   198

A-37     General Structure of the Wind-Stability Frequency File
         (FREQ. IN)	   200

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                               ACKNOWLEDGEMENTS
This document was prepared under Work Assignment No. 32 of Contract No. 68-03-
3513 by AQUA TERRA Consultants for the U.S. Environmental Protection Agency
Office of Research and Development.  Gerard Laniak of the Environmental
Research Laboratory in Athens, Georgia was the Technical Project Monitor and
Robert Carsel was the Project Officer.  We thank them for their continuous
technical and management support throughout the course of this project.

At AQUA TERRA Consultants,  the report was co-authored by Constance Travers and
Susan Sharp-Hansen, the Project Manager.  Anthony Donigian supplied technical
and administrative guidance and he and John Kittle reviewed the document.
Word processing was performed by Dorothy Inahara.  The material in Appendix A,
which summarizes the code structure and input format, and in Appendix B, which
lists the model subroutines, is based on a report by Salhotra and Mineart
(1988) .

A number of individuals were involved in the development and implementation of
the MULTIMED computational codes.  Key individuals include Jan Kool and Peter
Huyakorn of HydroGeoLogic Inc., Terry Allison of Computer Sciences
Corporation, Barry Lester of Geotrans Inc., Michael Ungs of TetraTech, Inc.,
Bob Ambrose of U.S. EPA, John Kittle of AQUA TERRA Consultants, and Rob
Schanz,  Yvonne Meeks, and Peter Mangarella of Woodward-Clyde Consultants.

The pre- and postprocessor for MULTIMED were developed by John Kittle and Paul
Hummel at AQUA TERRA Consultants.  Paul Hummel and Constance Travers created
the tutorials for the preprocessor.

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                                   SECTION  1

                                 INTRODUCTION
This document provides information needed to apply the U.S. Environmental
Protection Agency's Multimedia Model (MULTIMED)  to scenarios related to the
study and design of Subtitle D land disposal facilities.  Application of
MULTIMED to Subtitle D facilities requires the use of only a subset of the
model's capabilities.  MULTIMED's model theory documentation (Salhotra et al.,
1990) provides detailed information about the model's full capabilities.  In
this section, the model's full capabilities are first briefly addressed
(Section 1.1).  A summary of the methods used for application to the design of
Subtitle D facilities follows (Section 1.2).

1.1  OVERVIEW OF MULTIMED

MULTIMED simulates the transport and transformation of contaminants released
from a waste disposal facility into the multimedia environment.  Release to
either air or soil, including the unsaturated and the saturated zones, and
possible interception of the subsurface contaminant plume by a surface stream
are included in the model.  Thus, the model can be used as a technical and
quantitative management tool to address the problem of the land disposal of
chemicals in the multimedia environment.  At this time,  the air modules of the
model are not linked to the other model modules.  As a result,  the estimated
release of contaminants to the air is independent of the estimated contaminant
release to the subsurface and surface water.

MULTIMED utilizes analytical and semi-analytical solution techniques to solve
the mathematical equations describing flow and transport.  The simplifying
assumptions required to obtain the analytical solutions limit the complexity
of the systems with can be represented by MULTIMED.  The model does not
account for site-specific spatial variability, the shape of the land disposal
facility, site-specific boundary conditions, or multiple aquifers and pumping
wells.  Nor can MULTIMED simulate processes, such as flow in fractures and
chemical reactions between contaminants, which can have a significant affect
on the concentration of contaminants at a site.   In more complex systems, it
may be beneficial to use MULTIMED as a "screening level" model which would
allow a user to obtain an understanding of the system.  A numerical model
could then be used if there are sufficient data and necessity to justify the
use of a more complex model.

1.1.1  Model Capabilities

During the development of this model, emphasis was placed on the creation of a
unified, user-friendly, software framework, with the capability to perform
uncertainty analysis, that can be easily enhanced by adding modules and/or
modifying existing modules.

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To enhance the user-friendly nature of the model, separate interactive
preprocessing and postprocessing software has been developed for use in
creating and editing input and in plotting model output.  The pre- and
postprocessors,  PREMED and POSTMED, have not been integrated with MULTIMED
because of the size limitations of PC computers.  Therefore,  after using the
preprocessor to create or modify input,  the model is run in batch mode.
Afterwards, the postprocessor can be used to produce plots of the Monte Carlo
output or plots of concentration versus time for transient output.

The fate of contaminants critically depends on a number of media-specific
parameters.  Typically many of these parameters exhibit spatial and temporal
variability as well as variability due to measurement errors.  MULTIMED has
the capability to analyze the impact of uncertainty and variability in the
model inputs on the model outputs  (concentrations at specified points in the
multimedia environment), using the Monte Carlo simulation technique.

The major functions currently performed by this model include:

         •  Allocation of default values to some input parameters/variables.

         •  Reading of the input data files.

         •  Echo of input data to output files.

         •  Derivation of some parameters, if specified by the user.

         •  Depending on user-selected options:
                    simulation of leachate flux emanating from the source
                    simulation of unsaturated zone flow and transport
                    simulation of saturated zone transport only
                    computation of in-stream concentrations due to contaminant
                    loading assuming complete interception of a plume in the
                    saturated zone
                    computation of the rate of contaminant emission from the
                    waste disposal unit into the atmosphere
                    simulation of dispersion of the contaminants in the
                    atmosphere

         •  Generation of random input values for Monte Carlo simulations.

         •  Performance of statistical analyses of Monte Carlo simulations.

         •  Writing the concentrations at specified receptors to output files
            for deterministic runs.  In the Monte Carlo mode, writing the
            cumulative frequency distribution and selected percentiles of
            concentrations at receptors to output files.

         •  Printing the values of randomly generated input parameters and the
            computed concentration values for each Monte Carlo run.

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1.1.2  Interaction Framework (AIDE)

The pre- and postprocessor for MULTIMED have been developed using the ANNIE
Interaction Development Environment (AIDE)   (Kittle et al. ,  1989).
Consequently, the construction of input and the analysis of output is
standardized in terms of screen formats, movement within and between screens,
and methods of entering data, seeking on-line assistance and invoking
commands.  A full explanation of the conventions used is provided in Section
3.

1.2  APPLICATION OF MULTIMED TO SUBTITLE D LAND DISPOSAL FACILITIES

The U.S. EPA has developed several restrictions for Subtitle D applications of
MULTIMED.  These restrictions were made in an effort to develop a conservative
approach for simulating leachate migration from Subtitle D facilities.

   •     Only the Saturated and/or Unsaturated Modules may be active in
         Subtitle D applications, because the Surface Water, Landfill and Air
         Modules have not been sufficiently tested at this time.

   •     Although MULTIMED can simulate either steady-state or transient
         transport conditions,  only steady-state transport simulations are
         allowed for Subtitle D applications.  No decay of the source term is
         allowed; the concentration of contaminants entering the aquifer
         system must be constant in time.  The contaminant pulse is assumed
         continuous and constant for the duration of the simulation.

   •     The receptor must be located directly downgradient of the facility,
         so that it intercepts the center of the contaminant plume.  In
         addition, the contaminant concentration must be calculated at the top
         of aquifer.  Therefore, the angle from the plume centerline to the
         receptor and the vertical distance to the receptor must be specified
         as zero in Subtitle D applications.

Thus, MULTIMED can be applied at many Subtitle D land disposal facility sites
to simulate the transport of contaminants from the source,  through the
saturated and/or unsaturated zones by groundwater, to a receptor (i.e. a
well).   when MULTIMED is used in conjunction with a separate source model,
such as HELP (Schroeder et al.,  1984), it can be used in a variety of
applications.  These applications include 1) development and comparison of the
effects of different facility designs on groundwater quality, 2) prediction of
the results of different types of "failure" of the landfill, and 3) if
leachate migration into the groundwater below an existing waste disposal
facility occurs, prediction of the fate and transport of the contaminants in
the subsurface.  The user should bear in mind, however, that MULTIMED may not
be an appropriate model for application to some sites.  This issue, which is
discussed in Section 5.1, should be considered before modeling efforts
proceed.

As stated above, MULTIMED can be used in the design process to demonstrate
that a particular design will adequately prevent contaminant concentrations in
groundwater from exceeding health-based thresholds.  In other words, MULTIMED
combined with a source model can be used to demonstrate that either a landfill
design, or the specific hydrogeologic conditions present at a site will
prevent the migration of significant quantities of contaminants from the
landfill.  Procedures have been developed for the application of MULTIMED to
the design of Subtitle D facilities.  These procedures are outlined in Section
5.2.4 and are briefly summarized here.

   •     Collect site-specific hydrogeologic data

   •     Determine the contaminant to be simulated and the active modules in
         MULTIMED and the point of compliance

   •     Propose a landfill design and determine the corresponding

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         infiltration rate

   •      Run MULTIMED and calculate the dilution attenuation factor (i.e., the
         factor by which the concentration is expected to decrease between the
         landfill and the point of compliance)

   •      Based on the resulting dilution attenuation factor, determine if the
         design is acceptable

1.3  REPORT ORGANIZATION

This report contains the information needed to apply MULTIMED,  in conjunction
with another model,  such as HELP  (Schroeder et al.,  1984 a and b),  to Subtitle
D land disposal facilities.  Section 2 contains information about installation
and execution of the code.  In Section 3,  general information about the format
and operation of the pre- and postprocessors is provided and Section 4
describes how to use the pre- and postprocessors for Subtitle D applications
of the model.  Section 5 discusses the development of a conceptual model for
Subtitle D applications, the limitations and capabilities of MULTIMED, and
details about the input required to run each model module.  Help in estimating
some of the model parameters is contained in Section 6.  In Section 7,
appropriate example problems are included.  Finally, contained in Appendices
are 1) detailed information on the structure of the code and the format of
data in the input files, and 2) a listing of the subroutines in the code.

1.4  HOW TO USE THIS MANUAL

This application manual for the MULTIMED model and its pre- and
postprocessors, PREMED and POSTMED, is designed to be used by inexperienced as
well as experienced users.  Instructions are suggested for two types of
inexperienced users: the "hands-on, learn-as-you-go" user and the "read the
document first" user, as well as for the experienced user.  An experienced
user is defined as one who is already familiar with the basic capabilities and
operational aspects of PREMED,  MULTIMED and POSTMED, and wants to use the
programs to perform simulations.  These instructions are based on a similar
set of instructions found in Imhoff et al. (1990).

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''Hands-on,  Learn-as-you-go"  Users

  1.      Read Section 2  for  instructions  on model  installation  and execution.

  2.      Install  PREMED,  MULTIMED,  and POSTMED.  Execute  the  tests provided
         with the code and/or described in Section 2  to verify  that PREMED and
         POSTMED  are  properly installed.

  3.      From the DOS operating system,  execute  PREMED by typing    (do
         not  type the brackets).   The  opening screen  will appear.   utilize one
         of the two tutorials by typing either <@DETER.LOG>  for a
         deterministic Subtitle D  application or <@MONTE.LOG> for  a Monte
         Carlo Subtitle  D application.

  4.      Use  the  completed input sequence generated by the selected tutorial
         to run MULTIMED.   The input  sequence created by  the  <@DETER.LOG>
         tutorial is  the same as that  used in Example 2 in Section 7.   The
         input generated by  the <@MONTE.LOG> tutorial corresponds  to Example 3
         in Section 7.

  5.      Examine  the  output  generated  by  the MULTIMED model.  Because new
         versions of  MULTIMED may  be  released after publication of this
         document,  the output may  not  be  identical to the output  shown in
         Section  7.   Therefore,  compare the output generated  by MULTIMED with
         the  appropriate output file provided with the code.  This will allow
         you  to verify that  the MULTIMED  model is  properly installed.

  6.      Try  the  other example problems described  in  Section  7  to  become more
         familiar with MULTIMED.

  7.      Practice producing  plots  using POSTMED  and the SAT1.0UT  file
         generated when  the  Example 3  input is run.

  8.      Proceed  with suggestions  2 through 5 provided below  for  "experienced
         users."

''Read the Documentation  First" Users

  1.      Read Section 1  to familiarize yourself  with  the  basic  capabilities
         and  framework of the MULTIMED model.  If  you need more detailed
         information  on  the  capabilities  and limitations  of MULTIMED to
         determine if the model will be suitable for  your needs,  read Section
         5.1.

  2.      Read Section 3  which discusses the format and basic  operation of  the
         preprocessor,  PREMED.

  3.      Read Section 2  for  instructions  on model  installation  and execution.

  4.      Install  PREMED,  MULTIMED,  and POSTMED.  Execute  the  tests provided
         with the code and/or described in Section 2  to verify  that PREMED and
         POSTMED  are  properly installed.

  5.      From the DOS operating system,  execute  PREMED by typing    (do
         not  type the brackets).   The  opening screen  will appear.   utilize one
         of the two tutorials by typing either <@DETER.LOG>  for a
         deterministic Subtitle D  application or <@MONTE.LOG> for  a Monte
         Carlo Subtitle  D application.

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  6.      Section 4 discusses the use of the pre- and post-processor.   Read
         Section 4.1 in conjunction with the tutorial to provide a complete
         description of PREMED.

  7.      Use the completed input sequence generated by the selected tutorial
         to run MULTIMED.   The input sequence created by the <@DETER.LOG>
         tutorial is the same as that used in Example 2 in Section 7.   The
         input generated by the <@MONTE.LOG> tutorial corresponds to Example 3
         in Section 7.

  8.      Examine the output generated by the MULTIMED model.   Because new
         versions of MULTIMED may be released after publication of this
         document, the output may not be identical to the output shown in
         Section 7.  Therefore,  compare the output generated by MULTIMED with
         the appropriate output file provided with the code.   This will allow
         you to verify that the MULTIMED model is properly installed.

  9.      Try the other example problems described in Section 7 to become more
         familiar with MULTIMED.

 10.      Practice producing plots using POSTMED and the SAT1.0UT file
         generated when the Example 3 input is run.

 11 .     Proceed with suggestions 2 through 5 provided below for "experienced
         users."

Experienced Users

  1.      Read Section 2 and install PREMED, MULTIMED, and POSTMED.  Execute
         the tests provided with the code and/or described in Section 2 to
         verify that PREMED and POSTMED are properly installed,  and execute
         the test run for PREMED.

  2.      Read Section 5.2  which discusses applying MULTIMED to Subtitle D
         facility problems.  Refer to Section 5.1, which includes a discussion
         of issues related to conceptualization of the system, and the
         capabilities and limitations of MULTIMED, as needed.

  3.   Read Section 6 as needed to estimate parameters required by MULTIMED.

  4.   Try using MULTIMED to simulate actual scenarios.

  5.      If you wish to make changes to input files without using the
         preprocessor,  refer to Appendix A which discusses the format for
         input files.

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                                   SECTION 2

                      PROGRAM INSTALLATION AND EXECUTION
This section describes how to install and test MULTIMED and the related pre-
and postprocessor software on the user's computer.  Hardware and software
requirements are discussed.  Exact details of installation are included with
the software when it is distributed by the EPA Center for Exposure Assessment
Modeling (CEAM) at the Environmental Research Laboratory in Athens, Georgia.
If problems are experienced, the user should contact CEAM for support.

2.1  SYSTEM REQUIREMENTS

2.1.1  Hardware

MULTIMED and the related pre- and postprocessors, PREMED and POSTMED, were
designed to be used on an IBM-PC compatible computer.  The PC must have 640 KB
of memory,  a math coprocessor, and approximately 4 MB of free disk space.

Additional machines which should run the software include Digital Equipment
Corporation VAX computers running the VMS operation system,  Prime 50 Series
computer running PRIMOS and Sun Microsystems workstations running UNIX.
Contact CEAM for details.

2.1.2  Software

MULTIMED and its related software are written in FORTRAN 77.  If compilation
of the code is required, a FORTRAN compiler and linker are needed.  In
addition,  compilation of the preprocessor, PREMED, and postprocessor, POSTMED,
requires the use of ANNIE-IDE software (Kittle et al. ,  1989), which is
available from CEAM.  Graphics in the model postprocessor use the ANSI
Graphical Kernel System  (GKS).  If the graph features of the postprocessor are
to be used, then GKS device drivers are required for the user's output and
input devices.  Consult CEAM for additional information about obtaining these
device drivers.

2.2  LOADING THE EXECUTABLE CODE

Included with the distribution media for MULTIMED and its related pre- and
postprocessing software is a README.1ST document and file that provides
detailed instructions for installing the programs.  It is recommended that
data files be maintained in directories separate from the code.

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2.3  EXECUTING AND VERIFYING TEST SESSIONS

Sample input data files and the related output files are distributed with the
model.  In order to test the installation of MULTIMED,  the user should run
these example problems and compare the output generated by the code with the
output files supplied with the code.  The code is executed on a PC by typing
MULTIMED ( is the enter key).   The model will query the user for the
name of the input file and the name of the file to which output should be
written.   Be careful not to overwrite existing output files.

In order to test the installation of the preprocessor,  perform the following
check.  First,  execute the program  (on a PC type PREMED).   Next type the
following sequence of keys:

                        BCSMFURRYRY

Note that  is the F2 function key.  The screen in Figure 2.1 should appear
on the display screen.  To return to the operating system, type the key R.

The best test of the installation of the postprocessor is to plot the results
of the Monte Carlo simulation distributed with the model.  The output file is
called EX3SAT1.0UT.  First, execute the program (on a PC type POSTMED).
Next, for plotting results to the screen type the following sequence of keys:

                             DEX3SAT1.OUTP
A cumulative frequency plot will appear on the computer screen.  This plot
should be the same as the cumulative frequency plot found in the main output
file for the same problem.  After examining the plot,  press the Escape key,
Esc, to clear the plot from the screen.  To return to the operating system,
type the key R.

For computers without graphics capabilities,  the following check can be
performed.  After executing the program (on a PC type POSTMED),  type the
following sequence of keys:

                            DEX3SAT1.OUTS

At this point,  hit the down arrow key once, then type PRP.  The cumulative
frequency plot will be sent to the printer.  After the plot has been sent,
return to the operating system by typing the key R.

If there is a problem with any of the three software components of MULTIMED,
review the installation instructions carefully before calling CEAM for
support.

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                                   SECTION 3

              FORMAT AND OPERATION OF THE PRE- AND POSTPROCESSOR


A pre- and a postprocessor, PREMED and POSTMED, have been developed for
MULTIMED in order to improve the ease with which input can be created and/or
edited and output can be analyzed.  The pre- and postprocessors have been
developed using the ANNIE Interaction Development Environment (Annie-IDE)
(Kittle et al., 1989).  Consequently, user interaction within the program is
standardized in terms of screen formats,  movement within and between screens,
and methods of entering data,  seeking on-line assistance and invoking
commands.

Two tutorials are distributed with the preprocessor (see Section 4.1.3 for
information about running the tutorials).   These tutorials familiarize the
user with the operation and features of the preprocessor and are recommended
for new users.  Although no tutorial exists for the postprocessor, its format
and operation are identical to that of the preprocessor.  To complement the
tutorials, the format and operation of the screens are described in detail
below.  The summary is taken,  with minimal adaptation, from the manual for
another Annie-IDE application, called DBAPE (Imhoff et al.,  1989).

3.1  SCREEN FORMAT

Figure 3.1 defines the basic layout of a preprocessor screen.  The layout is
consistent for all screens used by PREMED, with specific kinds of information
always located at the same region of the screen.  Screen information is
divided into four components:  three windows (data window, assistance window,
instruction window)  and the command line.   For convenience,  the dimensions,
content, and important features of the four screen components are summarized
along the periphery of the screen area in the figure.

3.1.1  Data window

The top portion of the screen is the data window.  The data window contents
consist of one or more of the following.

          (1)         Prompts for user-supplied decisions by means of menu
                    selection

          (2)         Prompts for user-supplied data by means of form fill-in

          (3)         Echoes for current state of data


Two user-controlled sizes for the data window are used.  In the default
layout, the assistance window is not displayed, resulting in a two window, one
commandline screen (see Figure 3.2 for example).  If the user desires any of
the forms of assistance described in Section 3.1.2, then the data window is
reduced in size to accommodate the assistance window  (see Figure 3.3).


Conversely, the assistance window can be eliminated from the screen, thus
expanding the data window, by invoking the QUIET command ().  The pre- and
postprocessors accommodate up to 50 lines of data and enable scrolling in the
data window by using cursor keys when the data size exceeds the window size.
The title of the window and a series of one letter codes which identify the
sequence of screens which have led up to the current screen is displayed on
the upper left hand border of the data window.  Further explanation of the
"screen path" feature is provided in Section 3.3.3.

3.1.2  Assistance Window


                                      10

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Several types of user assistance are available within the pre- and
postprocessors.  A layered approach to assistance is used as follows.

         (1)        Use of descriptive and unique words or abbreviations for
                    field or menu option names in the data window always
                    provides "first-cut" definitions.

         (2)        When space allows, additional information in the data
                    window near the data field or menu option clarifies the
                    desired information.

         (3)        If additional parameter- or screen-specific assistance is
                    available,  it is supplied, upon request by the user, in
                    the assistance window.  Two types of screen-dependent
                    assistance can be displayed in the assistance window:
                    HELP and LIMITS.

         (4)        If assistance of a global nature  (i.e., independent of
                    individual screens)  is available, it, also, is displayed
                    in the assistance window upon request by the user.  The
                    three types of global assistance which can be displayed in
                    the assistance window are CMND,  STATUS and XPAD.


The layered "help" in PREMED and POSTMED is designed so that the user must
specifically request the higher levels of assistance; consequently,
experienced users are not subjected to unnecessary information.

As specified above, the assistance window, which is located directly below the
data window (Figure 3.1), is used to display the more detailed levels of
assistance  (HELP, LIMITS, CMND, STATUS and XPAD).   All types of detailed
assistance are further described later in this section.  The user selects one
assistance type at a time and the available assistance of that type is
displayed in the assistance window.  The title of the window (i.e., HELP,
LIMITS, CMND,  STATUS or XPAD)  is displayed on the left portion of the upper
border for the window and corresponds to the type of assistance which has been
requested by the user.  The types of assistance which are available for a
particular screen are indicated by the options listed in the command line
(Section 3.1.4).  If the amount of available assistance exceeds the window
size,  scrolling in the window by using cursor keys is allowed.

An example of screen layout for a three-window screen is shown in Figure 3.3.
Details on each of the assistance types which may be displayed within the
assistance window follow.

HELP

HELP assistance provides further information on model and system parameters
and menu options  (see Figure 3.4).  As noted above,  HELP text is specific to a
particular screen and can be scrolled in the assistance window.


LIMITS

LIMITS displays the allowable values for a specific field in the data window.
LIMITS information may be (1)  maximum and minimum acceptable numeric values or
(2) a list of acceptable alphanumeric values.  LIMITS text is specific to the
field currently highlighted in the data window, and it, also, can be scrolled.
Figure 3.5 shows the type of information displayed in the assistance window
when LIMITS has been selected.
                                      11

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CMND

CMND displays the names and definitions of all active commands at the current
location.  The command definitions never change.  It should be noted, however,
that the list of available commands varies according to location within the
program.  For example, the STATUS command is available only at certain program
"levels."  CMND text can be scrolled in the assistance window.

STATUS

STATUS assistance displays system status messages that summarize previous
actions and indicate the relative location of the user within the program
structure.  A maximum of 10 lines of STATUS assistance may be viewed by the
user at any point within an application; STATUS assistance cannot be scrolled.
Figure 3.6 illustrates the type of information displayed in the STATUS
message.  The screen contains the following information.

          (1)         Whether a file is being created or edited.  If editing an
                    existing file, the file name is given.

          (2)         The type of application (i.e.,  a generic model application
                    or a Subtitle D application).

          (3)         The scenario being modeled  (i.e., the MULTIMED modules
                    which have been selected by the user).

XPAD

Scratch pad (XPAD)  assistance allows the user to write notes and reminders
during an interactive session.  The user may record information in a single
XPAD with a maximum width of 78 characters and length of 10 lines.  Regardless
of where the user is located within the interactive session, a request for
XPAD assistance will call up the same XPAD with the same information.  XPAD
information in the assistance window can be scrolled.  New notes can be added
to existing notes,  and existing notes can be overwritten.

3.1.3  Instruction Window

The instruction window is always present on every screen.   In the screen
layout, it is located below the data and assistance windows and directly above
the command line (see Figure 3.1).  Two types of information are provided in
the window:  instructions for the user's next keystroke or error messages
reporting incorrect keystrokes with instructions for corrective actions.
Depending on which type of information is displayed by the system, the window
title on the screen will be either "INSTRUCT" or "ERROR."   Figure 3.5 gives an
example of the type of information commonly provided in an INSTRUCT-type
instruction window, and Figure 3.7 illustrates an ERROR-type instruction
window.

3.1.4  Command Line

The final component of the standard pre- and postprocessor screen is the
command line (Figure 3.1).   The command line is restricted to one line.  It
contains a menu of abbreviations for the available commands at the user's
current location within the program structure.  Definitions of the abbreviated
commands are available by invoking the CMND assistance in the assistance
window.

Table 3.1 lists the commands available in PREMED, the function keys used to
invoke commands, and command definitions.  Inspection of the command line in
Figure 3.1 shows that some of the commands are associated with the PC
functions keys and some are not.  Instructions on the alternate methods for
invoking the various commands are provided in Section 3.3.

A final feature of the command line is mentioned here to avoid confusion.  As


                                      12

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will be explained in the following section,  three  interaction  modes  can be
utilized: data mode, command mode, and assist mode.   The  command line appears
on the screen when the user is utilizing either  the  data  mode  or the command
mode.  when the user has invoked the assist  mode,  the command  line is removed
from the screen to avoid confusion, and command  instructions are displayed in
the instruction window.  When the user leaves the  assist  mode  to return to
either of the other two modes, the command line  reappears.

3.2  INTERACTION MODES

User interaction is organized into three "modes,"  each with a  specific
function:

         (1)        Use data mode to enter data  or select from menu  options in
                    data window.

         (2)        Use command mode to invoke commands or functions listed in
                    the command line; commands perform three functions:

            (a)     Allow exit from screens  (NEXT, PREV).
            (b)     Manage assistance window (HELP,  LIMITS, XPAD,  STATUS,
                    CMND, QUIET).
            (c)     Manipulate data window  (OOPS).

         (3)        Use assist mode to provide supplemental information in the
                    scratch pad (XPAD) on which  to base subsequent actions or
                    to scroll up or down in  the  assistance window.

Note that most tasks performed will only require use of the data and command
modes.
TABLE 3-1.  COMMANDS FOR APPLICATION OF  PREMED
444444444444444444444444444444444444444444444444444444444444444444444444444444
Command  Function
Name
CMND
         Kev
                    Command Definition
                     Display definitions of commands  in  assistance
                           information window
DNPG

HELP


LIMITS
         
                     Display next page in data window.

                     Display HELP information in assistance
           information window

                     Display limits of current field  in  assistance
                     information window
NEXT



OOPS



PREV

QUIET



STATUS
         







Go to next screen  (sets screen exit  status code
to 1)

Reset data values  in data window to  values when
screen was first displayed

Go to previous screen

Turn off assistance information window to allow
more room for data

Display system status in assistance  information
window
XPAD
         
                     Display users scratch pad, allow  changes
                                       13

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14

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Movement from each of the interaction modes to the other modes can be
accomplished as follows.
 data mode
 data mode
to command mode
to assist mode
 command mode to data mode
 command mode to assist mode
 assist mode to data mode
 assist mode to command mode
- press  key
- press function key associated with
  appropriate type of assistance or
  enter command mode and select
  appropriate assistance from options
  in command line

- press  key
- select appropriate type of
  assistance from options in command
  line

- press  key
- press  key twice (goes
  through data mode)
3.3  SCREEN MOVEMENT

Commands may be invoked either by pressing designated function keys or by
typing the first letter of a command name.  Likewise, menu options may be
selected either by moving the cursor to the selection field and confirming,  or
by typing the first letter (or letters, if needed)  of the menu item.

Several general features of user communication should be noted:

         (1)   There are no restrictions to upper- or lower-case mode.

         (2)   A key or command is always used to invoke the same function.

         (3)   Function keys are only used to invoke commands.

3.3.1  Movement Within Screens

Movement within screens may consist of (1) movement between interaction modes,
(2) movement between the three windows and the command line,  or (3) movement
within a window or command line.  The first type of movement,  between
interaction modes, has already been described in Section 3.2  and will not be
further considered here.  Procedures which cause movement within and between
the three windows and the command line of a screen are outlined below.  For
organization, the procedures which cause movement are categorized in terms of
the three interaction modes.

Data Mode--

In data mode, screen movement and operations may be accomplished by pressing
either printable character keystrokes, the  or  key, the cursor
keys or selected function keys.  However, the result of pressing some of these
keys depends on the type of screen which is presently displayed.
                                      15

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If one is prompted for decisions by means of a menu  (i.e., a menu screen),
keystrokes cause the following results.

          (1)         Type the first letter (or more,  if needed) of any option
                    in the menu in order to select the option.

          (2)         Use cursor keys to move between  highlighted menu options.

          (3)         Press function keys designated on the command line to
                    invoke the following commands.

             - HELP    - NEXT    - PREV    - XPAD

If one is prompted for data by means of form fill-in  (i.e., a data screen),
keystrokes cause the following results.

          (1)         Type alphanumeric characters needed to correctly fill in
                    the data screen; the characters  will be inserted in the
                    screen at the cursor position.

          (2)         Press  or  to end entry in one data field
                    and move to another.

          (3)         Use cursor keys to move within and among data screen
                    fields as needed.

          (4)         Use function keys to invoke the  following command
                    functions.

             - HELP    - NEXT    - PREV    - LIMITS
             - XPAD

Command Mode--

In the command mode, three categories of keystrokes  cause movement within
screens.

          (1)         All commands, with the exception of NEXT and PREV (see
                    Section 3.3.2), cause movement within screens. Type the
                    first character of any of these  commands to invoke the
                    command and cause activity in either the data or the
                    assistance window.  The activity caused by invoking each
                    command is summarized in Table 3-1.  As described in
                    Section 3.1.2, the commands CMND, HELP, LIMITS, STATUS,
                    QUIET and XPAD cause activity in the assistance window.
                    The command OOPS, which resets values in data screen to
                    the values present when the screen was first displayed,
                    causes activity exclusively in the data window.

          (2)         Press the  or  key to execute the command
                    currently highlighted in the command line.

          (3)         Use the right or left cursor keys to move the highlighting
                    to another command along the command line.

Assist Mode--

While the user is in the assist mode, keystrokes cause no actions whatsoever
unless (1) the scratch pad (XPAD) is active or (2) information which can be
scrolled is contained in the assistance window.  If  the scratch pad is active,
typed characters are inserted into the scratch pad at the current location of
the cursor.  The cursor can move in all directions,  and pressing the 
or  key causes the start of a new line.  Cursor keys can be used to
scroll up or down in any assistance window when the  available assistance
exceeds the window height.


                                      16

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17

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3.3.2  Movement Between Screens

A user can leave one screen and move on to another either by  (1) selecting a
menu option in the data window or (2) invoking commands displayed on the
command line.

Menu Options- -

Selection of a menu option always leads to a new screen.  From the data mode,
menu selections can be made by one of two methods.
         (1)
         (2)
Command Opt ions --
                    Type the first letter  (or letters, if needed) of the menu
                    item.

                    Move the cursor by use of cursor keys to the selection
                    field and confirm by typing  N.
Invoking either the NEXT or the PREV command results in movement to another
screen.  From the command mode, command selections can be made by one of three
methods .
         (1)

         (2)


         (3)



3.3.3  Screen Path
                    Type the first letter of the command.

                    Move the cursor by use of cursor keys to the selection
                    field in the command line and confirm by pressing .

                    For commands which are associated with a function key (as
                    indicated in the command line) ,  press the appropriate
                    function key.
During an interactive session, an aid is provided for remembering the sequence
of screens which have led up to the screen which is currently being displayed.
The screen path is connoted along the upper left hand border of the data
window following the window title (see Figure 3.7) .   The screen path is a
series of one or two letter codes which identify both (1) the type of
operations and  (2) the sequence of operations which have occurred from the
time the user leaves the opening screen until arriving at the current screen.
For example,  a screen path "BCS" in the preprocessor signifies that the
current screen is a result of  (1) selecting the Build option on the opening
screen, (2)  opting to Create a new input file, and  (3) selecting a Subtitle D
application.

As the user branches downward, a letter is added to the screen path each time
an operation is performed which results in the display of a new screen.  The
letter corresponds to the first letter of the option selected in the previous
screen.  In the case of some menus two letters are needed to differentiate
between options.  In such cases, both letters are added to the screen path.
Conversely,  upward movement,  which is accomplished by using the Return option
in any menu,  results in the elimination of a letter from the screen path.

It should be noted that familiarity with screen sequencing can also speed up
the time it takes to perform frequent tasks.  After memorizing the screen path
needed to perform a sequence of operations and, hence, arrive at a particular
location in the program, one may type ahead and pass quickly over intermediate
screens .
                                      23

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                                   SECTION 4

                      USE OF THE PRE- AND POSTPROCESSORS
The preprocessor, PREMED, allows the user to easily create an input file for
use in MULTIMED.  The postprocessor, POSTMED, provides a means of generating
graphs of concentration versus time and the results of Monte Carlo analysis.
Both of these programs are designed to be fully interactive and easy to use.
Many of the features and options available in the pre- and postprocessors are
discussed in Section 3.

4.1  THE PREPROCESSOR  (PREMED)

4.1.1  Use of the Preprocessor

Before using the preprocessor, read the section on installation and execution
of MULTIMED (Section 2).

To execute the preprocessor, move to the directory which contains the
preprocessor and type  (do not type the brackets).   After a moment the
Opening screen will appear,  as shown in Figure 4.1.

If you are unfamiliar with PREMED, it is strongly recommended that you utilize
the tutorials which are included with the preprocessor.  These tutorials can
be accessed from the Opening screen by typing either <@DETER.LOG> or
<@MONTE.LOG> (do not type the brackets).  The tutorials are discussed in
Section 4.1.3.

The Opening screen displays several options.  At this time, only the
Build/Modify and Return  (to operating system) options can be used.  Currently
it is not possible to analyze model results or execute MULTIMED from the
preprocessor.   You can analyze the results from Monte Carlo simulations using
the postprocessor, POSTMED.   Viewing results or executing MULTIMED requires
that you return to the operating system.

You must use the Build/Modify option to create or edit an input file for
MULTIMED.  Select this option by typing   (do not type the brackets).   The
Build/Modify screen will now be displayed as shown in Figure 4.2.

From this screen, you may either create, edit,  or save an input sequence for
use in MULTIMED.  If you select the Edit option (by typing ) you will be
prompted for the name of a preexisting input file  (Figure 4.3).  Type the name
of a file, and select the "Next" option by pressing  to continue with the
program.

If you select the Create option,  the Create screen will be displayed.  Figure
4.4 shows the Create screen.  This screen displays options for either a
Generic or a Subtitle D application of MULTIMED.  Only Subtitle D applications
are discussed in this manual.  Since it is intended for regulatory
application,the Subtitle D application of MULTIMED restricts the options
available for simulation to those which have been thoroughly tested.
Therefore, only the scenario involving the Unsaturated Zone and Saturated
Zones may be executed, and the Landfill, Surface Water, or Air Modules may not
be used.  Furthermore, the Subtitle D-specific applications may only be run in
steady-state mode.

The next screen which will be displayed by PREMED is the General-1  (BEG)
screen.  This screen allows input of information in the General Data group.
Figure 4.5 shows the appearance of the General-1 screen when the user has
chosen to create a Subtitle D input sequence.  If a Generic application is
selected on the Create screen, then the default values on the General-1 screen


                                      24

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will be different.

The Run Title is allowed a maximum of two lines.  You may use any title for
your simulation that you want.  In Subtitle D applications, the Run Option may
be either deterministic or Monte Carlo,  but the simulation must be run in
steady-state. Factors which should be considered when selecting these options
are discussed in Section 5.

The various modules in MULTIMED which will be active in the simulation must be
selected.  The Subtitle D application may include only the Saturated Zone
and/or Unsaturated Zone Modules.  The Saturated Zone Module should be used
alone only if the water table is located directly below the bottom of the
waste disposal facility.  In all other cases, the effects of unsaturated flow
and transport from the bottom of the facility to the water table cannot be
considered negligible, and the Unsaturated Zone Modules should be included in
the simulation.  At this time, the other modules shown in Figure 4.5 (Surface
water, Air and Landfill) have not been sufficiently tested.  Subtitle D
applications must be run in steady-state.  After the General-1 parameters have
been specified, press  for "Next" to move to the next screen.

If the Monte Carlo option is selected,  the General-1 (BEG) screen will be
followed by the General-2  (BEG)  screen (Figure 4.6).  This screen requires the
following input: the number of Monte Carlo simulations, the desired output
from the model, and the confidence level  (in %) for the 80th, 85th,  90th and
95th estimated percentiles.  Estimation of the number of Monte Carlo
simulations and confidence levels are discussed in Section 6.6.  The amount of
output is related to the number of output files which are opened by the model:


LOTS-    Opens all ".VAR" and ".OUT" files (i.e., writes the Monte Carlo
         variables for each simulation and the corresponding output) and the
         main output file.

SOME-    Opens only the main output file, "STATS.OUT" and "SAT1.0UT".

NONE-    Opens only the main output file and "STATS.OUT".  Note that the
         postprocessor cannot be used if this amount of output is selected,
         since POSTMED requires the "SAT1.0UT" file for the simulation.

After the General-2 (BEG) screen parameters have been set as desired, press
the  to move to the next screen.

The Edit (BE) screen will now be displayed as shown in Figure 4.7.  This
screen allows access to the nine data groups included in MULTIMED:  the
General, AQuifer, Air, source, surface.  Chemical, Funsat, Landfill and Tunsat
data groups.  Not all of these data groups are required for a specific
simulation.  For example, if the Air Module was not selected as an active
module on the General-1  (BEG) screen, then the Air data group option on the
Edit  (BE) screen does not need to be selected.  To determine which parameters
are required for a particular scenario (i.e., combination of MULTIMED
modules), refer to the section in the MULTIMED model theory documentation
(Salhotra et al., 1990) which describes the module.

The parameters in the General data group have already been specified on the
General-1  (and General-2) screens.  However,  if you wish to make changes to
this data group, type  to select this option.

The Undef option on the Edit  (BE) screen lists the data groups which contain
undefined parameters.   This option is selected by typing .  The data groups
displayed contain undefined parameters which will need to be defined before
the input sequence is complete for use in MULTIMED.  To return to the Edit
screen, press the  function key.

The other data group options on the Edit  (BE) screen can be selected by typing
enough characters to make the selection unique.  For example, there are two


                                      25

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options which begin with "A", so if you wish to select the AQuifer data group,
you must type .   Selection of a data group will be followed by a screen
which is specific to that data group,  and contains a list of parameters or
parameter groups which are contained in that data group.

Six data groups contain parameters which are used in simulations of Subtitle D
facilities: General, AQuifer, source.  Chemical, Funsat and Tunsat.  The
General data group has already been discussed.  The data group-specific
screens for each of the other groups are shown in Figures 4.8 through 4.12.
Each of these screens contains a Return (to Edit screen)  option, and an option
to list Undefined parameters within the data group.  Undefined parameters are
those which do not have a data value assigned to them.  They are designated by
a -999 in the input file.

The rest of the options shown in the data-group specific screens are either 1)
parameter names or 2)  sub-data groups  which contain additional parameters.
For example, selection of the Type option on the AQuifer screen (Figure 4.8)
will be followed directly by a screen  where a parameter value is specified.
In this case, the Type of source for the saturated zone model is specified.
However, selection of the Depth option on the AQuifer screen will be followed
by another screen which contains several parameters related to the size and
particle characteristics of the aquifer: PArticle diameter, POrosity of
aquifer. Bulk density. Depth of aquifer and Mixing zone depth.  You will need
to select one of these options to specify actual values for the parameters.
Any of the options may be selected by  typing enough characters to make the
selection unique.

The specification of a parameter value is similar for all of the parameters in
the data groups.  Therefore, specification of the aquifer porosity will be
used as an example.   The other parameters can be specified in a similar
manner.

From Table 5-8, it can be determined that the aquifer porosity is part of the
Depth and Particle Characteristics sub-data group which is part of the AQuifer
data group.   Therefore, the AQuifer option should be selected from the Edit
(BE) screen by typing .   PREMED will now display the AQuifer  (BEAq) screen
as shown in Figure 4.8.  This screen contains five sub-data groups: the Depth,
Type, Hydraulic, Misc and Times data groups.  The aquifer porosity is included
in the Depth (and particle characteristics of the aquifer)  sub-data group.
Select this option by typing .


The Depth  (BEAqD) screen will now be displayed.  Figure 4.13 shows this screen
which contains five parameters for which values may be specified:  the
PArticle, POrosity,  Bulk, Depth, and Mixing.  Select the POrosity option on
the Depth  (BEAqD) screen by typing .  The screens which follow this
selection will differ for the Deterministic and Monte Carlo simulations.  Both
types of simulations are discussed below.

Deterministic simulation:

         Some of the parameters in MULTIMED may be derived from other
         parameters instead of being specified directly by the user.  The
         aquifer porosity is one of these parameters which can be derived.
         Therefore,  the Depth screen is followed by the POrosity  (BEAqDPo)
         screen, shown in Figure 4.14, which provides two options: 1) Derive
         the aquifer porosity value from other parameters in MULTIMED or 2)
         Specify the value of the aquifer porosity.  If the Derive option is
         selected, PREMED will return  to the Depth (BEAqD)  screen.  However,
         if the Specify option is chosen,  the preprocessor will display the
         screen shown in Figure 4.15.   The value of the aquifer porosity
         should be entered on this screen.  After the porosity has been
         specified,  press  to return to the Size screen.
                                      26

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Monte Carlo simulation:

         The screens which will be displayed for a Monte Carlo simulation are
         identical to those for a deterministic simulation until the value for
         a specific parameter is to be input.  In a Monte Carlo simulation,
         the probability density distribution for each parameter required by
         MULTIMED must be specified.

         In the example discussed above,  when the POrosity option is selected
         from the Depth (BEAqD) screen, the screen which follows is shown in
         Figure 4.16.  The probability density distribution for the POrosity
         is specified on this screen.  It is very important that the
         distribution selected adequately reflects the actual probability
         density distribution for the parameter.  A discussion of probability
         density distributions is included in the MULTIMED model theory
         documentation (Salhotra et al. ,  1990).

         Each of the distributions requires that some characteristics of the
         distribution be specified.  For example, if a LOGNormal distribution
         is selected for the POrosity, the minimum and maximum values,  the
         mean and the standard deviation are required, as shown in Figure
         4.17.   The requirements for the different distributions are discussed
         in Section 9 of the MULTIMED model theory documentation (Salhotra et
         al. ,  1990) .


Eventually, you will wish to exit the preprocessor.  If you do not wish to
save any of the changes you have made to the input file, you may simply type
 at any point and the program will be terminated.  However,  if you
would like to save your changes you will need to exit the program in the
following manner:

  1.     Select the Return option from the screen menus until you return to
         the Edit  (BE) screen.

  2.     Select the Return (to Build screen)  option from the Edit screen.

  3.     If undefined parameters exist, the Return (BER) screen will be
         displayed as shown in Figure 4.18.  This screen lists the data groups
         which contain undefined parameters.   At this point, you may either 1)
         Return to the Edit screen and specify the remaining undefined
         parameters or 2)  Return to the Build screen and ignore these
         undefined parameters.

  4.     From the Build/Modify screen  (Figure 4.2), select the Save option by
         typing .

  5.     The Save  (BS) screen will now be displayed as shown in Figure 4.19.
         The name of the input file for use in MULTIMED should be specified on
         this screen.  Note that you should use a name which is compatible
         with your computer system.  For example, the DOS operating system on
         an IBM PC will allow at most 8 characters in the main filename and 3
         characters in the extension on the filename.  Other operating systems
         may have different restrictions.  Press  to return to the
         Build/Modify screen.

  6.     To exit the program, select the Return  (to Opening screen)  option
         from the Build/Modify screen by typing .

  7.     The execution of MULTIMED must be done from the operating system of
         your computer.  Therefore, select the Return  (to operating system)
         option from the Opening screen.
                                      27

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4.1.2  The PREMED Tutorials

Two tutorials are included with the preprocessor.  These tutorials are
intended to familiarize a user with the options and utilization of PREMED.  It
is strongly recommended that an inexperienced user take advantage of the
tutorials provided with MULTIMED.   Completion of these tutorials creates
complete input files for use in MULTIMED.

The tutorials are specific to the application of MULTIMED to Subtitle D
facilities.  One tutorial generates an input file for deterministic, steady-
state simulation of flow and transport in the unsaturated zone, and transport
in the saturated zone.   The second tutorial is similar to the first tutorial
except that it is run in a Monte Carlo framework.  The input generated by the
Deterministic tutorial, and the corresponding MULTIMED output,  are discussed
in Section 7.2.  Input and output for the Monte Carlo tutorial  are presented
in Section 7.3.

To utilize either of these tutorials, you must first begin the  preprocessor
program by typing  (do not type the brackets) from the  DOS operating
system.  After a few seconds, the Opening screen for the preprocessor will
appear.  To activate the tutorials you must type either <@DETER.LOG> for the
Deterministic tutorial, or <@MONTE.LOG> for the Monte Carlo tutorial.

The tutorial will be presented in a small box on the right hand side of the
screen.  An example of a tutorial screen is shown in Figure 4.20.  Directions
for completing the tutorial will appear in this box.  In the tutorial, you
will edit a pre-existing input file which is almost complete.  This input file
has been specially designed to contain a small number of parameters which
still need values.  These are called "undefined" parameters, and will need to
be supplied to the preprocessor in order to complete the input  file.  The
tutorial will provide instructions so that you can complete the file.  In the
process, many of the options in the preprocessor will be demonstrated.

Successful completion of the tutorials will generate the completed input
sequence shown in Tables 7-4 and 7-7.  These input sequences can then be used
to run MULTIMED and generate the output in Tables 7-5 and 7-8.   Output from
the Monte Carlo tutorial, can be used with the postprocessor, POSTMED.


4.2 - THE POSTPROCESSOR  (POSTMED)

The postprocessor can be used to generate plots to show the results of Monte
Carlo analyses or concentration versus time.  These plots are generated from
the main output file and "SAT1.0UT" which are generated by MULTIMED during
execution.  For comparison of different simulations, POSTMED allows up to
three different data files to be plotted on the same graph.  Output from
POSTMED may be written to the screen, to a printer, to a plotter, or to a file
in text form.

4.2.1  Use of the Postprocessor

Before using the postprocessor, read the section on installation and execution
of MULTIMED  (Section 2).
                                      28

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In order to use POSTMED, you must copy the appropriate MULTIMED output file
into the directory which contains the postprocessor. For Monte Carlo Analyses,
the MULTIMED output file "SAT1.0UT" is used,  which is generated automatically
during execution of MULTIMED.  Note that the "SAT1.0UT" file will be
overwritten each time the model is run.  Therefore, if you wish to save this
file for use with the postprocessor,  you should rename it.  This is
particularly important if you want to plot the results from more than one
simulation on the same graph; the "SAT1.0UT"  files for each simulation must be
given a different name.  For Concentration versus Time plots,  the file which
should be copied into the POSTMED directory is the main output file.  POSTMED
will select the information necessary for generating Concentration versus Time
plots from this file.

To execute the postprocessor, move to the directory which contains the
postprocessor and type   (do not type the brackets).   After a moment
the Opening screen will appear, as shown in Figure 4.21.  Use the Data option
of the Opening screen to provide the postprocessor with information about
MULTIMED data files which you wish to plot.  Type a  (do not type the
brackets) to select this option.

POSTMED will now display the Data-1 (D) screen.  The number of Multimedia
Model runs which you wish to plot should be entered on this screen.  The valid
values which may be entered on this screen can be seen by pressing the 
key.  The limits for the parameter will then be displayed in the center,
assistance window,  as shown in Figure 4.22.  As you can see,  a minimum of 1
and a maximum of 3  runs may be plotted on a single graph.

After entering a value on Data-1  (D)  screen,  select the "Next" option by
pressing  to go to the next screen.  The Data-2 (D) screen will now be
displayed (Figure 4.23).  This screen is used to enter the name of the file(s)
which contain MULTIMED results to be plotted.  This screen will appear once
for each run.  After entering the name of the file, press  to go to the
next screen.

After entering the last file, the postprocessor returns to the Opening screen.
Type  to describe the specifications of the plot.  POSTMED will now display
the Specs (S) screen as shown in Figure 4.24.  Several options are available
on this screen.

  1.     The Graphics device must be specified.  You may send the plot
         generated by POSTMED to the screen  (DISPLAY), a printer or a plotter.
         If your computer will not support graphics, it may be desirable to
         send the plot directly to a printer.  Alternatively,  the coordinates
         used to generate the plot may be sent either to the screen or to a
         TEXT file.

  2.     The X- and Y-axis types must be specified.  Either arithmetic or
         logarithmic scales may be used.  Note that logarithmic scales can not
         be used with FREQUENCY plots.  If a logarithmic scale is selected,
         the number of logarithmic cycles for each axis must be specified.

  3.     The location of the legend on the plot must be specified.  The
         options are: UL (upper left), LL  (lower left) , UR (upper right), LR
         (lower left).

  4.     You must specify the type of plot you wish to create.  Three choices
         are allowed: a cumulative frequency plot  (CUMULATIVE), a frequency
         plot  (FREQUENCY)  or a concentration versus time plot  (TIME).   The
         FREQUENCY plot provides information about the number of times a
         particular concentration was obtained, which is displayed in
         histogram format.   Selection of the CUMULATIVE option will generate a
         plot showing the cumulative frequency of concentration values.  The
         TIME option plots concentration versus time for transient runs.
                                      29

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  5.     The Y minimum and Y maximum (in percent)  of the plot should be
         specified.  The minimum value must be less than the maximum.

To move between options, press .   To select an option, type
enough characters to make the selection unique.  For example, the Graphics
device options (Figure 4.24) are: DISPLAY,  PRINTER, PLOTTER, TEXT, SCREEN.  If
you wish to select DISPLAY,  you may type only .   However, if you want to
send your results to a printer, you must type two characters, , since
there are two options beginning with "P".  Once you have selected the desired
options on the Specs (S) screen,  press  to return to the Opening screen.

Titles for the Graph, the x- and y-axis, and the different runs can be entered
on the Titles (T) screen.  From the Opening screen, type  for this
selection.  This screen is shown in Figure 4.25.  Any character string may be
used as a title.   Use the  to move between options.  Press
 to return to the Opening screen.

Now you are ready to generate a plot.  If you wish to make any changes to the
any of the screens, type the first letter of the menu item to select the
option, make the necessary changes, and return to the Opening screen by
pressing .  Otherwise, type 

to generate the plot. The plot will then be sent to the Graphics device that you specified on the Specs (S) screen. A cumulative frequency plot showing the results of the simulation of an example problem is presented in Figure 4.26. The corresponding frequency plot is shown in Figure 4.27. Figure 4.28 shows the first screen of the text file generated by selecting the SCREEN option for the same example problem. Selection of the TEXT option will send the same file to a specified file. Now, you may either repeat the process described above and generate additional plots, or type to return to the operating system. 30


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Figure 4.26
                                      31

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Figure 4.27
                                      32

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                                   SECTION 5
                               MODEL APPLICATION
The large number of interrelated physical, chemical and biological processes
involved in the migration of leachates from waste disposal facilities makes
the prediction of groundwater contamination from these facilities a complex
task.  Mathematical models are useful tools which provide insight into the
effects on groundwater quality of facility design,  operation and failure.

All models are simplified representations of the real system; no model will
ever reproduce the exact characteristics of a site.  Therefore, model results
should always be interpreted as estimates of groundwater flow and contaminant
transport, and not as exact predictions.  Bond and Hwang (1988) recommend that
models be used for comparing various cases or scenarios,  since all cases are
subject to the same limitations and simplifications.  Furthermore, models are
useful for sensitivity analysis, determining the effects of varying one
parameter on the model results.  It is important to understand the limitations
of mathematical models, and to use them correctly in evaluation of actual
environmental conditions.

Several recent reports present detailed discussions of the issues related to
model selection, application, and validation.  Donigian and Rao (1988) address
each of these issues.  Issues related to model selection and application are
addressed in detail by Boutwell et al.   (1986).  Weaver et al.  (1989)  discuss
the selection and field validation of mathematical models.   In addition, a
report by the National Research Council (1990) discusses model application and
validation and provides recommendations for the proper use of groundwater
models.  Model users, particularly those who are relatively inexperienced, are
encouraged to read these and similar reports before beginning a modeling
study.

The validity of the results from mathematical models depends to a large extent
on the proper application of the model.  The application of a model to a
leachate migration problem requires several steps.   First,  the modeling needs
and the objectives of the study should be determined.  Next, data should be
collected for characterization of the hydrological, geological, chemical and
biological conditions present in the system.  These data should assist in the
development of the "scenario" to be modeled, which provides the framework for
the conceptual model of the system.  The conceptual model and data are used to
verify that the selected model is appropriate.  During model application,
results should be calibrated to obtain the best fit to observed data.
Finally, these results should be validated by comparing them to independently-
derived data or observations.
                                      46

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In order to apply a model to a specific site, it is necessary to describe the
"scenario" to be represented by the model.  A scenario is essentially a
description of all the important processes and characteristics of a particular
site.  Although it may be possible to describe the "average" characteristics
of a Subtitle D landfill or surface impoundment, it would be dangerous to
assume that this description adequately describes all such facilities.  Each
site is unique, and must be characterized separately.  This section describes
some of the issues which should be considered when developing a scenario and
using MULTIMED to represent the conceptual model of the site.

One of the most severe limitations to modeling is insufficient data.
Uncertainty in model predictions results from our inability to characterize a
site in terms of the boundary conditions or the key parameters describing the
important flow and transport processes  (National Research Council,  1990).  The
results of MULTIMED are highly dependent on the quantity and quality of the
available data.  The application of MULTIMED to a site requires the collection
of a large amount of data,  and the process of applying MULTIMED to a scenario
may reveal data deficiencies which require additional data collection.

Based on the available data and the judgement of the modeler, values of the
required parameters should be determined.  Parameter values which must be
determined for Subtitle D applications are discussed in Section 5.3.  Section
6 of this manual provides guidance for estimation of parameters for use in
MULTIMED.  Inexperienced modelers may attempt to apply the model when the lack
of site-specific data causes the model results to be highly speculative.  It
must be emphasized that a mathematical model should never be used as a
substitute for data in site-specific applications.

As stated above, the conceptual model and data should be used to determine
whether or not a mathematical model is appropriate for representing the
subsurface system and which options in the model should be utilized.  The
model should:

   •     Allow the objectives of the study to be achieved

   •     Adequately simulate the significant processes present in the actual
         system
   •     Be consistent with the complexity of the study area

   •     Be appropriate for the amount of available data

Some of the factors which should be considered before applying MULTIMED to a
particular site are summarized in Table 5-1.  This list is not exhaustive, and
is meant only to provide guidance.  The factors in Table 5-1 are addressed in
terms of MULTIMED's capabilities and limitations in the following section.

5.1  MULTIMED CAPABILITIES AND LIMITATIONS

5.1.1  Solution Techniques

MULTIMED utilizes analytical and semi-analytical solution techniques to solve
the mathematical equations describing flow and transport.  These solution
                                      47

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TABLE 5-1.  ISSUES TO BE CONSIDERED  BEFORE  APPLYING MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444444444444
Objectives of the Study

   •     Is a "screening  level"  approach  appropriate?

   •     Is modeling a "worst-case  scenario"  acceptable?


Significant Processes Affecting  Contaminant Transport

   •     Does MULTIMED simulate  all  the significant processes occurring
         at the site?

   •     Is the contaminant  soluble  in water  and of the same density
         as water?


Accuracy and Availability of  the Data

   •     Have sufficient  data been  collected  to obtain reliable results?

   •     what is the level of uncertainty associated with the data?

   •     Would a Monte Carlo  simulation be useful?   If so,  are the
         cumulative probability  distributions for the parameters with
         uncertain values known?


Complexity of the Hydrogeologic  System

   •     Are the hydrogeologic properties of  the system uniform?

   •     Is the flow in the  aquifer  uniform and steady?

   •     Is the site geometry regular?

   •     Does the source  boundary condition require a transient
         or steady-state  solution?
                                       48

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techniques have advantages and disadvantages over fully numerical models.
Analytical solutions are computationally more efficient than numerical
simulations and are more conducive to uncertainty analysis  (i.e. Monte Carlo
techniques).   Typically, input data for analytical models are simple and they
do not require detailed familiarity with the code or extensive modeling
experience.  Analytical solutions are typically the most efficient alternative
when data necessary for the characterization of the system are sparse
(Javandel et al.,  1984).  The limited data available in most field situations
may not justify the use of a detailed numerical model; in some cases, results
from simple analytical models may be just as meaningful (Huyakorn et al.,
1986) .

However,  analytical models require simplifying assumptions about the system
which are not necessary for numerical models.  These simplifications result in
models which include relatively few processes and a limited number of
parameters which are often required to be constant in space and time (van der
Heijde and Beljin,  1988).   MULTIMED is no exception; the representation of the
system simulated by the model is simple, and little or no spatial or temporal
variability is allowed for the parameters in the system.

Bond and Hwang (1988)  present guidelines for determining whether the
assumption of uniform aquifer properties is justified at a particular site.
In more complex systems, it may be beneficial to use MULTIMED as a "screening
level"  model which would allow a user to obtain an understanding of the
system.  A numerical model could then be used if there are sufficient data and
necessity to justify the use of a more complex model.

A highly complex hydrogeological system cannot be accurately represented with
MULTIMED.  Heterogeneous or anisotropic aquifer properties, multiple aquifers
and complicated boundary conditions cannot be simulated using this model.
MULTIMED cannot simulate processes, such as flow in fractures and chemical
reactions between contaminants, which can have a significant effect on the
concentration of contaminants at a site.  Since each site is unique,  it must
be left to the modeler to determine which conditions and processes are
important at a specific site, and to determine the suitability of applying
MULTIMED.

5.1.2  Spatial Characteristics of the System

Although actual landfills and groundwater systems are three-dimensional,  it is
common to reduce the number of dimensions simulated in a mathematical model to
one or two.  Two and three-dimensional models are generally more complex and
computationally expensive than one-dimensional models, and therefore require
more data.  In some instances, a one-dimensional model may adequately
represent the system.   Furthermore, the available data may not warrant the use
of a multidimensional  model.

However,  modeling a truly three-dimensional system using a one-dimensional
model may produce inaccurate results.  Three-dimensional effects are often
very significant in describing processes such as contaminant plume migration.
The choice of the number of dimensions in the model should be made for a
specific site, based on the conditions present at that site.  The information
which is desired from the model output should also be considered.

MULTIMED has the following spatial characteristics:

•         The Unsaturated Flow Module simulates vertical, one-dimensional flow.

•         The Unsaturated Transport Module simulates vertical, one-dimensional
         transport.  Dispersion is only considered in the longitudinal
          (vertical) direction.
                                      49

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•         The Saturated Transport Module assumes one-dimensional, horizontal
         flow.  However,  three-dimensional dispersion may be simulated since
         the effects of lateral or vertical dispersion may significantly
         affect the model results.

These spatial assumptions should be considered when applying MULTIMED to a
site.  The assumption of flow only in the vertical direction may be valid for
facilities which receive uniform areal recharge.  The assumption may not be
valid in facilities where surface soils (covers or daily backfill)  or surface
slopes result in an increase of runoff in certain areas of the facility and
ponding of precipitation in others (Kirkham et al.,  1986).

The simulation of one-dimensional, horizontal flow in the saturated zone
requires several assumptions.  The saturated zone is treated as a single,
horizontal aquifer with uniform properties.  The effects of pumping or
discharging wells on the groundwater flow system cannot be considered.  These
assumptions should be considered when applying MULTIMED to a site.

5.1.3  Steady-State versus Transient Flow and Transport

The MULTIMED model assumes steady-state flow in all applications.  Some
groundwater flow systems are in an approximate "steady-state", in which the
water entering the flow system is balanced by the water leaving the system.
There is no significant temporal variation in the system.  The assumption of
steady-state conditions in a model generally simplifies the mathematical
equations used to describe processes, and reduces the amount of input data,
since no information about temporal variability is necessary.

However, assuming steady-state conditions in a system which exhibits transient
behavior may produce inaccurate results.   For example, climatic variables,
such as precipitation vary in time and may have strong seasonal components.
In such areas, the assumption of constant recharge of the groundwater system
is incorrect.  In general, this assumption will cause underestimation of
contaminant concentrations in the subsurface, since steady-state models can
not simulate the effects of individual storms, which can provide a substantial
driving force for contaminant transport.

MULTIMED can simulate either steady-state or transient transport conditions.
The assumption of steady-state transport requires that the contaminant source
has a sufficiently large mass to ensure that the downgradient concentration,
once reached, will be maintained  (Mulkey et al., 1989).   It must be assumed
that the source is continuous and constant.  If these assumptions can not be
made at a particular site, inaccurate results will be produced by a steady-
state transport model.  Steady-state models are also inappropriate when the
simulation includes chemicals which sorb or transform significantly (Mulkey et
al., 1989).  Note that although the steady-state model can be very
conservative, this may be appropriate for some applications.  The choice of
simulating steady-state or transient conditions should be made based the
objectives of the study and on the degree of temporal variability in the
system.
                                      50

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5.1.4  Monte Carlo versus Deterministic Simulations

MULTIMED may be run in either a deterministic or a Monte Carlo framework.  In
a deterministic simulation, exactly one model result is determined for a given
set of input values.  All of the input variables are assumed to have a fixed
mathematical relationship with each other, which completely define the system.
Monte Carlo simulations,  however, consider the intrinsic randomness and
uncertainties inherent in the system.  The Monte Carlo method provides a means
of estimating the uncertainty in the results of a model, if the uncertainty of
the input variables is known or can be estimated.  For each of the uncertain
variables, a cumulative probability distribution must be determined.  The
Monte-Carlo technique involves running a model a large number of times with
different values of input parameters, which are determined from probability
distributions,  and then analyzing the results.  The Monte Carlo option is
discussed in Section 9 of the MULTIMED model theory documentation  (Salhotra et
al.,  1990).

There are many sources of uncertainty in the prediction of leachate migration
in the subsurface.  Uncertainties may be due to measurement error in
parameters which describe the physical and chemical properties of the system,
the presence of spatial and temporal variability in the parameters, or
incompletely understood processes which are simulated by the mathematical
model.  There may be some uncertainty associated with extrapolating data from
one set of conditions to a different set of conditions.  Therefore, it may be
more appropriate to express these uncertain input parameters in terms of a
probability distribution rather than a single deterministic value and to use
an uncertainty propagation model to assess the effect of the variability on
the model output  (Salhotra and Mineart, 1988) .

The specified uncertainty in the input parameters for MULTIMED is highly site-
specific.  Available data for many sites are scarce and even sites which are
very well-characterized may exhibit a substantial amount of variability in
measured parameter values.  Most of the parameters in the MULTIMED model may
be assigned a Monte Carlo distribution.  It must be left to the user of the
MULTIMED model to determine which input parameter values are uncertain at a
particular site.

Although the Monte-Carlo method can be a useful tool for quantitatively
evaluating uncertainty in a model,  it is not without problems.  One difficulty
is related to determining the cumulative probability distribution for a given
parameter.  These distributions must be determined from a large amount of
data, which may not be available.  Assuming a parameter probability
distribution when the distribution is unknown does not help reduce
uncertainty, as the certainty of the output is then a function of the assumed
certainty of the input parameter (U.S. EPA, 1988) .   Furthermore, in order to
obtain a valid estimate of the uncertainty in the output, the model must be
run numerous times  (typically at least several hundred times) which can be
computationally expensive.  These issues should be considered before utilizing
the Monte-Carlo technique.
                                      51

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5.1.5  Boundary conditions

The source boundary condition for MULTIMED relates to the introduction of the
contaminant to the aquifer system.  MULTIMED is limited to relatively simple
representations of the source of groundwater contamination.   Only two types of
source geometries can be simulated by MULTIMED: a patch source or Gaussian
distributed source.  Temporally, these source geometries may be described as
either: 1) continuous 2)  exponentially decaying or 3)  a non-decaying pulse of
finite duration.  These types of sources are discussed in Section 5 of the
MULTIMED model theory documentation (Salhotra et al.,  1990).

5.2  SUBTITLE D APPLICATIONS OF MULTIMED

5.2.1  Summary of EPA Requirements for MULTIMED Simulations  of Leachate
       Migration from Subtitle D Facilities

The U.S. EPA has developed several restrictions for Subtitle D applications of
MULTIMED.   These restrictions were made in an effort to develop a conservative
approach for simulating leachate migration from Subtitle D facilities.

   •      Only the Saturated and/or Unsaturated Modules may be active in
         Subtitle D applications, because the Surface Water, Landfill and Air
         Modules have not been sufficiently tested at this time.

   •      Although MULTIMED can simulate either steady-state  or transient
         transport conditions, only steady-state transport simulations are
         allowed for Subtitle D applications.  No decay of the source term is
         allowed; the concentration of contaminants entering the aquifer
         system must be constant in time.  The contaminant pulse is assumed
         continuous and constant for the duration of the simulation.

   •      The receptor must be located directly downgradient  of the facility,
         so that it intercepts the center of the contaminant plume.  In
         addition, the contaminant concentration must be calculated at the top
         of aquifer.  Therefore, the angle from the plume centerline to the
         receptor and the vertical distance to the receptor  must be specified
         as zero in Subtitle D applications.

   •      Only the Gaussian source geometry is allowed in SubtitappMcations.

The application of MULTIMED to Subtitle D facilities simulates the transport
of contaminants from the source, through the saturated and/or unsaturated
zones by groundwater, and to a receptor  (i.e. a well).   Although the Landfill
Module in MULTIMED can not be used at present because it has not been
sufficiently tested,  MULTIMED can be used in conjunction with another source
model, such as HELP  (Schroeder et al., 1984), to develop and compare the
effects of different facility designs on groundwater quality.  MULTIMED
combined with a source model could be used to demonstrate that either the
landfill design, or the specific hydrogeologic conditions present at the site
will  prevent the migration of significant quantities of leachate from the
landfill.   Furthermore, MULTIMED could be used to predict the results of
different types of "failure" of the landfill.  If leachate migration into the
groundwater below a waste disposal facility occurs, MULTIMED could be useful
in predicting the fate and transport of the contaminants in  the subsurface.

5.2.2  Active Modules

Flow and transport in the subsurface typically occurs through the unsaturated
zone, to the water table and into the saturated zone.   However, in some
instances, the water table may be located just below the waste disposal
facility,  so that only saturated flow and transport away from the facility
need to be considered.  Therefore, two basic simulation options are allowed
for Subtitle D applications of MULTIMED: 1)  flow and transport in the
unsaturated zone coupled with transport in the saturated zone or 2) saturated
transport only. The simulation of the system should accurately represent the


                                      52

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moisture conditions present at the site.

Simulation of these options in MULTIMED requires that the Saturated Zone
Module, and, if the water table is located at a significant depth below the
waste disposal facility, the Unsaturated Flow and Transport Modules, be
active.   Use of the Saturated Zone Module requires four data groups: the
General, Chemical,  Source,  and Saturated Zone Data Groups.  If the Unsaturated
Flow and Transport Modules are active, two additional data groups must be
used: the Unsaturated Flow and Transport Data Groups.  The parameters required
in each of these data groups are discussed in Section 5.3.2.

5.2.3  Boundary conditions

Although MULTIMED can simulate two source geometries, only the Gaussian
distributed source is allowed in Subtitle D applications.  Temporal variation
in the source term boundary conditions in MULTIMED are not allowed for
Subtitle D applications, which must be run in steady-state.  Therefore,
although constant pulse and exponential decay boundary conditions are allowed
for generic applications of MULTIMED, only a constant source is allowed in
Subtitle D applications.

5.2.4  Procedure for Application of MULTIMED to Subtitle D Facility Design

MULTIMED can be used to assist in the design of Subtitle D landfills  (Figure
5.1).  As the flowchart shows, the role of MULTIMED in the design process is
to evaluate the ability of a particular design to insure that groundwater
concentrations of chemicals expected to exist in Subtitle D landfills do not
exceed health based thresholds.  A step-wise procedure for determining the
minimum design necessary to protect groundwater at these levels and keyed to
the flowchart shown in Figure 5.1 follows:

1)       Collect site-specific hydrogeological data.  These data may include
         aquifer particle size, porosity, bulk density,  hydraulic conductivity
         and gradient, groundwater velocity, dispersivities, and thickness.
                                      53

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Figure 5 .1
                                      54

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Lists and a discussion of the parameters required for Subtitle D
applications of MULTIMED are presented in Section 5.3.  See Section 6
for guidance in parameter estimation.

Based on water level measurements, determine whether or not the
Unsaturated Zone Modules should be active in the simulation.  If the
unsaturated zone will be simulated, collect site-specific data on the
properties of the unsaturated zone.

Determine contaminant which will be simulated.   The selection of the
contaminant to be simulated may be based on a variety of factors or
it may be prescribed.  It may be a chemical which is particularly
persistent in the subsurface environment, or is present in high
concentrations in the specific Subtitle D facility.  Determine
chemical properties for the selected contaminant (see Section 6).

Propose landfill design and determine the infiltration rate at the
site.  This can be done using a water balance model, such as HELP
(Schroeder et al.,  1984), which includes representations of
engineering controls.  Note that infiltration rate as used here means
the volumetric flow rate in meters per year from the bottom of the
landfill into the unsaturated zone or aquifer.   Obviously,  the
attenuation of this flow is the objective of landfill engineering
controls.  For each specific landfill design, there is a resulting
steady-state infiltration rate.

Run MULTIMED using the Subtitle D application type, the
hydrogeological data collected in Step 1, the infiltration rate
determined in Step 2, and with the point of compliance set to the
required location.   As discussed above, the Subtitle D application
assumes steady-state conditions and the point of compliance (POC)
must be along the plume centerline.  You may wish to set the input
leachate concentration to 1.0 mg/1 for convenience in later
calculations (see step 6) .

The EPA-recommended criteria for establishing whether or not a
particular design is acceptable is based on the dilution-attenuation
factor  (DAF).   This method is based on the fact that the model
estimate of concentration at the point of compliance is linear with
respect to the input concentration.  Therefore, the DAF is the factor
by which the concentration is expected to decrease between the
landfill and the point of compliance.

Using the concentration predicted by MULTIMED at the point of
compliance, the dilution-attenuation factor  (DAF)  for the
landfill/aquifer system may be calculated using the following
equation:
                             55

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         DAF = leachate concentration / concentration at the POC

            or, if the leachate concentration is 1.0 mg/1 in the model,

         DAF = 1.0 / concentration at the POC


7)       If the DAF is equal to or greater than 100, the design is acceptable
         (see discussion below).   Otherwise, the landfill design must be made
         more stringent by increasing the number or effectiveness of
         engineering controls so that the infiltration rate is reduced.  To
         evaluate the new design,  repeat Steps 2-5.  Continue until an
         acceptable design is reached (DAF is equal to or greater than 100).


The threshold DAF of 100 is used to define an acceptable design because the
maximum allowable leachate concentration of chemicals expected to exist in a
Subtitle D landfill is 100 times the Maximum Contaminant Level (MCL) for each
chemical (U.S. EPA, 1990).  This approach to determining the expected
concentration of constituents in leachate from a Subtitle D landfill is
attractive because of its consistency with other regulations and its generic
nature.  If site-specific conditions permit the use of other approaches which
are acceptable to an approved state, these may be used.

5.3  MULTIMED INPUT REQUIREMENTS

As discussed above, the MULTIMED code consists of seven modules which are
described in Salhotra et al. (1990).  Only three of the modules can be used
for Subtitle D applications of the model: the Saturated Zone Transport Module,
the Unsaturated Zone Flow Module,  and the Unsaturated Zone Transport Module.
The Saturated Zone Transport Module is required for all Subtitle D
applications and can be applied independently of the Unsaturated Zone Modules.
Depending on site-specific conditions, the Unsaturated Zone Modules may or may
not be needed.  Note that the two Unsaturated Zone Modules must be used in
conjunction with each other and with the Saturated Zone Module.

The operation of each module requires specific input, which is organized into
data groups.  The General Data Group, which is required for all simulations,
contains flags and data which describe the scenario being modeled.  The input
parameters needed for the Saturated Zone Transport Module are found in three
additional data groups: the Chemical Data Group, the Source Data Group, and
the Aquifer Data Group.  Use of the Unsaturated Zone Modules requires input
found in the same data groups,  as well as two others: the Unsaturated Zone
Flow Data Group and the Unsaturated Zone Transport Data Group.

In this section, parameter requirements are discussed in two stages.  Section
5.3.1 introduces the input parameters required by each of the three modules
which can be active in Subtitle D applications.  In Section 5.3.2, the
parameters in each data group are presented and the options available for
specifying their values in the code are summarized.  Help in estimating these
parameters is provided in Section 6.

5.3.1  Parameter Requirements Summarized by Module

5.3.1.1  The Saturated Zone Transport Module--

The primary input parameters required to compute a contaminant concentration
in the saturated zone for Subtitle D applications are shown in Table 5-2,
organized according to the data group in which they are found.  A number of
the parameters listed in Table 5-2 can be derived using other variables and a
set of empirical, semi-empirical,  or exact relationships.  Note that some of
the parameters used to derive the primary parameters can also be derived.
Table 5-3 indicates which parameters can be derived and lists the additional
variables needed.  The methods used to derive the parameters are described in
Section 6 of this document or in Section 5.5 of Salhotra et al. (1990).  Note


                                      56

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that both particle diameter and porosity can not be simultaneously derived,
since one is derived from the other.

5.3.1.2  The Unsaturated Zone Flow Module--

The input parameters required to compute flow in the unsaturated zone are
shown in Table 5-4.  Note that only one input variable in the Source Data
Group is needed.  The remaining variables are all located in the Unsaturated
Zone Flow Data Group.  None of these parameters can be derived.

5.3.1.3  The Unsaturated Zone Transport Module--

Table 5-5 lists the parameters used to compute contaminant transport in the
unsaturated zone.  The variables are located in five different data groups.
Note that an overall chemical decay coefficient and distribution coefficient
for the unsaturated zone can not be entered directly,  as they can in the
saturated zone module.  Rather, they are calculated in the code using methods
described in Section 5.5.2.1 of Salhotra et al. (1990).  Of the parameters
shown in Table 5-5, only the longitudinal dispersivity can be derived.

5.3.2  Parameter Requirements Summarized by Data Group

This section is written with the assumption that the modeler will use the
preprocessor,  PREMED, to create and modify input files for Subtitle D
applications (see Section 4).  Thus, the organization of the information in
this section is compatible with that of the preprocessor.  The parameters are
listed in tables according to data group.  Further, the parameters listed in
each of the data group tables are organized according to the preprocessor
screen in which they can be found.  Advanced users, who choose to modify input
files directly without the use of the preprocessor, will notice that there is
some discrepancy between the organization of data in the preprocessor (and
this section)  and the structure of the input file,  which is discussed in
Appendix A.

5.3.2.1  General Data Group--

The General Data Group screens of the preprocessor contain flags which allow
the user to specify the run options and active modules for the input file.
The choices made in this data group determine which parameters must be
specified in
the rest of the input.  Therefore, the General Data Group should always be
                                      57

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TABLE 5-2.  PRIMARY  PARAMETERS USED IN THE SATURATED  ZONE  TRANSPORT MODULE
            FOR  SUBTITLE D APPLICATIONS OF MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444444444444
Parameters
                                                                    Units
Source Data Group  Parameters

         Area of the  land disposal facility

         Leachate  concentration at the waste facility

         Recharge  rate  into the plume

         Infiltration rate    from the facility

         Standard  deviation (i.e., spread) of the
         source

Aquifer Data Group Parameters

         Type of source geometry  (only Gaussian allowed)

         Porosity

         Thickness of the aquifer

         Thickness of source (i.e.,  mixing zone depth)

         Seepage velocity

         Dispersivities (longitudinal, transverse,
         vertical)

         Retardation  coefficient
[dimensionless]

         Radial distance from  the site to the receptor

Chemical Data Group Parameters

         Effective first-order decay coefficient

         Distribution coefficient
[m2]

[mg/1,  g/m3

[m/yr]

[m/yr]


[m]
[cc/cc]

[m]

[m]

[m/yr]


[m]




[m]



[1/yr]

[cc/g]
                                       58

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TABLE 5-3.  PARAMETERS  USED  TO DERIVE OTHER SATURATED ZONE TRANSPORT
            MODULE  PARAMETERS  NEEDED IN SUBTITLE D APPLICATIONS OF MULTIMED
444444444444444444444444444444444444444444444444444444444444444444444444444444
Parameters
                                                                    Units
Overall Chemical Decay  Coefficient

         Biodegradation rate
         Solid phase  decay coefficient
         Dissolved phase decay coefficient
         Bulk density
         Distribution coefficient
         Porosity

Solid and Dissolved Phase Decay Coefficients

         Reference temperature
         Aquifer temperature
         Second-order acid-catalysis hydrolysis rate
           constant at  reference temperature
         Second-order base-catalysis hydrolysis rate
           constant at  reference temperature
         Neutral hydrolysis rate constant at reference
           temperature
         pH of the aquifer

Retardation Coefficient

         Bulk density
         Distribution coefficient
         Porosity

Bulk Density

         Porosity

Porosity

         Mean particle  diameter of the porous medium

Particle Diameter

         Porosity
[1/yr]
[1/yr]
[1/yr]
[g/cc]
[cc/g]
[cc/cc]
[f/mole-yr]

[f/mole-yr]

[1/yr]
[pH  units]
[g/cc]
[cc/g]
[cc/cc]
[cc/cc]
[cm]
[cc/cc]
                                                                    (continued)
                                       59

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TABLE 5-3.  PARAMETERS  USED TO DERIVE OTHER SATURATED ZONE TRANSPORT
            MODULE  PARAMETERS NEEDED IN SUBTITLE D APPLICATIONS  OF
            MULTIMED  (concluded)
444444444444444444444444444444444444444444444444444444444444444444444444444444
Parameters
                                                                    Units
Distribution Coefficient

         Normalized  distribution coefficient
            for organic carbon,  Koc
         Fractional  organic  carbon content
[dimensionless]

Seepage Velocity

         Hydraulic gradient
         Hydraulic conductivity
         Porosity

Hydraulic Conductivity

         Porosity
         Mean particle diameter of the porous medium

Thickness of the Source  (Mixing Zone Depth)

         Length of the land  disposal facility
         Thickness of the  aquifer
         Seepage velocity
         Porosity
         Infiltration rate    through the facility
         Vertical dispersivity

Standard Deviation of the  Source

         width of the land disposal facility

Length and Width of  the Facility

         Area of the land  disposal facility

Dispersivities

         Radial distance  from the site to the receptor
[cc/g]
[m/m]
[m/yr]
[cc/cc]
[cc/cc]
[cm]
[m]
[m]
[m/yr]
[cc/cc]
[m/yr]
[m]
[m]
[m2]
[m]
                                       60

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TABLE 5-4.  PARAMETERS REQUIRED  IN THE  UNSATURATED ZONE FLOW MODULE
            FOR SUBTITLE D APPLICATIONS OF MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444444444444

Parameter                                                    Units
Source Data Group Parameters

         Infiltration rate  from the  facility                 [m/yr]

Unsaturated Zone Data Group Parameters

         Number of physical flow layers                       [dimensionless]

         Number of porous materials                           [dimensionless]

         Thickness of each  layer                             [m]

         Material associated  with each  layer                 [dimensionless]

For each material:

         Air entry pressure head                             [m]
         Porosity                                             [dimensionless]
         Saturated hydraulic  conductivity                    [cm/hr]
         Residual saturation  (water  content)                  [dimensionless]
         Either:
            van Genuchten alpha coefficient                  [I/cm]
            van Genuchten beta  coefficient                   [dimensionless]
         or
            Brooks and Corey  exponent                         [dimensionless]
            van Genuchten alpha coefficient                  [I/cm]
            van Genuchten beta  coefficient                   [dimensionless]
Note:    The model provides  the  option to use either van GenuchtenTs or Brooks
         and Corey's constitutive  relationship for relative permeability
         versus water  saturation.   However,  the relationship between pressure
         head and water  saturation is  expressed in terms of van Genuchten
         parameters.
                                       61

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TABLE 5-5.  PARAMETERS  REQUIRED IN THE UNSATURATED ZONE TRANSPORT MODULE
            FOR SUBTITLE  D  APPLICATIONS OF MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444444444444
Parameters
                                                             Units
                                                              [dimensionless]
                                                              [m]
                                                              [m]
                                                              [g/cc]
                                                              [1/yr]
                                                              [dimensionless]
                                                              [cc/cc]
Source Data Group  Parameters

         Source concentration at top of unsaturated zone     [mg/f]

Unsaturated Zone Transport  Data Group Parameters

         Control parameters related to the evaluation
         schemes used  in  the  module

         Number of  layers used to simulate transport

For each layer:

         Thickness
         Longitudinal  dispersivity
         Bulk density  of  the  soil
         Biodegradation rate,
         Percent organic  matter

Unsaturated Zone Flow  Data  Group Parameters

         Porosity  of the  unsaturated zone

Aquifer Data Group  Parameters

         Temperature of the aquifer3                          [°C]

         pH of the  aquifer3                                   [pH units]

Chemical Data Group Parameters

         Normalized distribution coefficient (i.e., Koc)      [cc/g]

         Reference  Temperature                               [°C]

         Acid and  base hydrolysis rates at reference
         temperature
[l/mole-yr]

         Neutral hydrolysis rate at reference temperature    [1/yr]


3   Note:  the temperature  and pH  used  in  calculating the unsaturated zone
overall    chemical decay rate are the temperature and pH specified  for  the
aquifer.
                                       62

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completed first. The information which needs to be supplied for all model
applications is:

Title--Two lines of text can be entered.  The text, which is used to label the
input and output, can consist of two character strings, each up to 78
characters in length.

Run Option--The default run option is Deterministic.  However, the user has
the option of selecting a Monte Carlo run instead.  Issues related to the
choice between these two options are addressed in Section 5.1.4.  In addition,
Monte Carlo simulations are discussed in Section 9 of Salhotra et al. (1990) .

Active Modules--For Subtitle D applications, the default for active modules is
Unsaturated Zone/Saturated Zone.  However, the user can choose that the
Saturated Zone alone be active.  The Air, Landfill, and Surface Water Modules
can not be accessed for Subtitle D applications.

Transient versus Steady-state--For Subtitle D applications, the user has no
choice for this flag.  Simulations must be steady-state.

For Monte Carlo simulations, additional information is required in the General
Data Group.  The additional information is:

Number of Monte Carlo Simulations--Typically hundreds to thousands of Monte
Carlo simulations are needed to obtain meaningful results.  Section 9.9 of
Salhotra et al.  (1990)  provides information on the estimation of this value.

Level of Output from Monte Carlo Runs--The default for this flag is SOME,
which means that the main output file and the STATS.OUT and SAT1.0UT files are
created  (see Section A.2 for a description and listing of the output files).
The two other options available to the user are LOTS, which opens the maximum
number of output files, and NONE,  which opens only the main and STATS.OUT
files.  Note that in order to use the postprocessor to create frequency and
cumulative frequency plots, the file SAT1.0UT is needed and thus, this flag
must be set to either LOTS or SOME.   A few of the files created using the LOTS
flag can be very large, depending on the number of Monte Carlo simulations.
On many PC computers, these files can fill all available disk space and cause
the simulation to fail.  Thus, on PC's the default of SOME is recommended.

Confidence Level (in percent) for the Four Estimated Percentiles--ln Monte
Carlo mode, MULTIMED calculates confidence bounds for the 80th, 85th, 90th,
and 95th percentiles.  The confidence bounds are discussed in Section 9.8 of
Salhotra et al.  (1990).

5.3.2.2  Chemical Data Group--

The MULTIMED parameters contained in the Chemical Data Group are shown in
Table 5-6.  Note that some of the parameters are associated with the Surface
Water and Air Modules of MULTIMED and thus, are not used for Subtitle D
applications of the model.  Further, note that five of the parameters (i.e.,
the solid phase, liquid phase, and overall  decay coefficients, the
distribution coefficient, and the biodegradation coefficient)  are used only in
the Saturated Zone Module.  Other parameters may be used by more than one
model module.
                                      63

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TABLE 5-6.   PARAMETERS IN THE CHEMICAL (Chemical) DATA GROUP
444444444444444444444444444444444444444444444444444444444444444444444444444444
Parameter  [units]        Derived                             Specified
Default
                               C       N       Ln      Exp      U       LoglOU  Emp
444444444444444444444444444444444444444444444444444444444444444444444444444444
Decay Coefficients:

Solid phase  decay coeff.      _______
          (sat.  zone)   [1/yr]

Dissolved phase decay         _______
          (sat.  zone)   [1/yr]

Overall chemical decay        _______
          (sat.  zone)   [1/yr]

Hydrolysis Rate Constants and Reference Temperature:

         Acid  catalyzed       _______
         hydrolysis  [1/M-yr]

Neutral catalyzed             _______
         hydrolysis  [1/yr]

Base catalyzed                _______
         hydrolysis  [1/M-yr]
                                                                                          SB
            Comments
               Value
Reference
          temperature [oC]
Various Coefficients:
Normalized  distribution
         coeff.  [ml/g]

Distribution  coeff.
          (sat.  zone)  [ml/g]
         144
         C      =   Constant
         N      =   Normal
         Ln    =   Lognormal
                                                 Exp    =   Exponential
                                                 U      =   Uniform
                                                 LoglOu =   LoglOUniform
Emp    =  Empirical
SB     =  Johnson SB
G      =  Gelhar
                                                        64

-------
TABLE 5-6.  PARAMETERS IN THE CHEMICAL  (Chemical) DATA GROUP  (concluded)
                                                          444444444444
                                                          Specified

                                     N       Ln       Exp      U        LoglOU  Emp
Parameter  [units]       Derived
Default         Comments
                              C
Biodegradation coeff.         _____
          (sat. zone)  [1/yr]

Air diffusion coeff.
         Not used in Subtitle D
          [cm2/s]  applications.

Temperature for air
         Not used in Subtitle D
         diffusion  [oC] applications.

Molecular Definitions, Solute Vapor  Pressure, Henry's  Constant:
Molecular weight  [g/mole]     Not used  in  Subtitle  D  applications.

Mole fraction of solute  [--]  Not used  in  Subtitle  D  applications.

Solute vapor pressure  [mm Hg] Not used  in  Subtitle  D  applications.

Henry's Law const.  [atm-m3/M] Not used  in  Subtitle  D  applications.
                                       SB
              Value
         C     =  Constant
         N     =  Normal
         Ln    =  Lognormal
Exp    =  Exponential
U      =  Uniform
LoglOu =  LoglOUniform
Emp    =  Empirical
SB     =  Johnson SB
G      =  Gelhar
                                                      65

-------
Table 5-6 indicates that four of the parameters in the Chemical Data Group can
be derived.   If the user chooses to have the code calculate the values of
these parameters,  additional parameters are needed (see Table 5-3).   All of
the Chemical Data Group parameters can be assigned a constant value or,  in
Monte Carlo mode,  can be assigned one of seven Monte Carlo distributions.  If
a Monte Carlo distribution is selected for any of the parameters,  additional
information defining the distribution must be entered for that parameter (see
Table 5-7).   The Monte Carlo distributions are described in Section 9.5  of
Salhotra et al.  (1990).  Also,  limited help in determining the appropriate
Monte Carlo distribution for a particular parameter is provided in Section 6.

Most of the parameters are undefined initially in the preprocessor and must
have a value assigned to them before an input file can be completed.  Note
that three of the parameters have a default value of zero assigned initially.
The default values can be changed at the user's discretion.

5.3.2.3  Source Data Group--

Table 5-8 lists the parameters in the Source Data Group.  Note that in
Subtitle D applications the source is assumed to be continuous and non-
decaying.  Therefore, two of the parameters, the duration of the pulse and the
source decay constant, can not be modified by the user.  Refer to Tables 5-2
through 5-5 in order to determine which of the remaining parameters are  needed
for specific model applications.

The values specified for the infiltration rate and the initial chemical
concentration entering the subsurface from the facility are difficult to
determine and yet are critical to the modeling effort. Refer to Section  5.2.4
for information about the values to use for these parameters when designing
Subtitle D facilities. Some general information is also provided in Section 6.

Three of the parameters listed in Table 5-8 can be derived.  The derivation of
these parameters is described in Section 6 and Table 5-3 summarizes the
parameters needed for the derivations.  All of the Source Data Group
parameters can be assigned a constant value or, in Monte Carlo mode, can be
assigned one of seven Monte Carlo distributions described in Section 9.5 of
Salhotra et al.  (1990).  Refer to Table 5-7 for a list of the additional
parameters required when a Monte Carlo distribution is specified for an  input
parameter.

5.3.2.4  Aquifer Data Group--

The parameters in the Aquifer Data Group of the preprocessor are shown in
Table 5-9.  This data group contains the largest number of parameters of all
the data groups, but many of them are "secondary" parameters  (i.e.,  parameters
used to derive the "primary" parameters or other "secondary" parameters).
Depending on selections made by the user, some of these "secondary"  parameters
may not be used by the code.  Refer to Tables 5-2 and 5-3 and to Section 6 in
order to understand the relationships between these parameters and parameters
in other data groups.
                                      66

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TABLE 5-7.  PARAMETERS REQUIRED FOR SELECTED PROBABILITY  DENSITY  DISTRIBUTIONS
444444444444444444444444444444444444444444444444444444444444444444444444444444
Distribution

Normal

Lognormal

Exponential

Uniform

Log10uniform

Johnson SB

Empirical
Required Parameters

minimum, maximum, mean, standard deviation

minimum, maximum, mean, standard deviation

minimum, maximum, mean

minimum, maximum

minimum, maximum

minimum, maximum, mean, standard deviation

minimum, maximum, up to 20 pairs of data
defining the probability and
associated value  (which describe the
distribution)
The parameters used to specify well location are restricted  in  Subtitle  D
applications.  Only the downgradient distance  from the  site  can be  input by
the user.  Otherwise, it is assumed that the well is on the  plume centerline
and screened at the top of the aquifer.  The well angle off  center  and
vertical distance can not be modified, nor can they be  assigned a Monte  Carlo
distribution.

In the preprocessor, the geometry of the source boundary condition  for the
aquifer is specified in the Aquifer Data Group.  For Subtitle D applications,
only a Gaussian source is allowed which is described in Section 5 of  Salhotra
et al .   (1990) .   Therefore, default value set in the preprocessor is Gaussian.
All of the Aquifer Data Group parameters which are not  being derived  can be
assigned either constant values or, in Monte Carlo mode,  one of seven
distributions  (see Table 5-9) .  Note that an eighth distribution type is
available in Monte Carlo mode for the longitudinal, transverse,  and vertical
dispersivities--the Gelhar distribution.  This special  distribution is
described in Section 6.5.10 and summarized in  Table 6-12 (a) .

5.3.2.5  Unsaturated Zone Flow Data Group- -

Table 5-10 shows the parameters in the Unsaturated Zone Flow Data Group.  The
parameters listed under the heading "Control Parameters"  will influence  the
type of data which can be input in this data group.  Thus, these three
parameters should be specified first.  Each has been assigned a default  value
which can be changed based on site-specific information.   The default values
are 1 flow layer, 1 material type, and the use of van Genuchten parameters  to
determine the relationship between relative permeability and water  saturation.
Note that the number of materials can never be greater  than  the number of
layers.  Also note that the same material type can be assigned  to more than
one layer.
                                      67

-------
TABLE 5-8.   PARAMETERS IN THE CONTAMINANT SOURCE  (SOurce)  DATA GROUP
444444444444444444444444444444444444444444444444444444444444444444444444444444
Parameter  [units]        Derived                            Specified
Default                                                                                               Comments
                               C      N        Ln       Exp     u       LoglOU   Emp      SB     G        Value

Infiltration rate              ________
      [m/yr]

Area of waste unit             ________
      [m2yr]

Duration of  pulse   [yr]        Not needed because  Subtitle D applications must be steady-state

Spread of  source               _________
      [m]

Recharge rate                 ________
      [m/yr]

Source Decay constant         _                                                                         0
         Set = 0  for  Subtitle D applications

Initial concentration         ________
      [mg/1]

Length scale [m]               _________

Width scale  [m]                _________

         C      =   Constant              Exp    =   Exponential                 Emp    =  Empirical
         N      =   Normal                U      =   Uniform                     SB      =  Johnson SB
         Ln     =   Lognormal             LoglOu =   LoglOUniform                G      =  Gelhar
                                                       68

-------
TABLE 5-9.   PARAMETERS IN THE AQUIFER  (AQuifer)  DATA GROUP
Parameter  [units]   Derived
Default
                                                             Specified
C
                                        N
                                              Ln    Exp    u    Log10U  Emp
Depth and Particle  Characteristics:
)))))))))))))))))))))))))))))))))))
Particle                          •


   diameter  [cm]  porosity is derived.
   ))))))))))))
Porosity  [--]                     ••
                Cannot  be derived if particle
   diameter  is  derived.
                                               Cannot be derived if aquifer
Bulk Density  [g/cc]
Aquifer thickness
    [m]
Source thickness
    [m]
Type of Source  (Gaussian or Patch) :
))))))))))))))))))))))))))))))))))))))))))
Hydraulic- and  Dispersion-Related Parameters:
Hydraulic Conductivity
    [m/yr]
Hydraulic gradient
Seepage velocity
   [m/yr]

            C
            N
            Ln
Constant
Normal
Lognormal
                                                     Gaussian
                  Exp    =  Exponential
                  U      =  Uniform
                  Log10u =  Log10Uniform
                                                                                                             Comments
                                                                                 SB
                                                                                                 Value
                                                                                    Emp
                                                                                    SB
                                                                                    G
                                                                                           =  Empirical
                                                                                           =  Johnson SB
                                                                                           =  Gelhar
                                                          69

-------
TABLE 5-9.  PARAMETERS  IN  THE  AQUIFER (AQuifer) DATA GROUP

Parameter  [units]   Derived       _ Specified
Default
Retardation coeff.
Longitudinal
     Dispersivity  [m]
Transverse
     Dispersivity  [m]
vertical
     Dispersivity  [m]
Miscellaneous Parameters:
)))))))))))))))))))))))))
Temperature  [ C]
                                                                                                            Comments
                                       N
                                             Ln
                                                   Exp
                                                          u   Log10U  Emp
                                                                                 SB
                                                                                                Value
Organic carbon
     content  [fraction]
C     =  Constant
N     =  Normal
Ln    =  Lognormal
                                                   Exp    =  Exponential
                                                   U      =  Uniform
                                                   Log10u  =   Log10Uniform
                                                                                   Emp    =  Empirical
                                                                                   SB     =  Johnson  SB
                                                                                   G      =  Gelhar
                                                          70

-------
TABLE 5-9.  PARAMETERS  IN THE AQUIFER (AQuifer) DATA GROUP  (concluded)
                   [44444444444444444444444444444444444444444444444444444444444
                    Derived       	Specified
Parameter  [units]
Default
Well -Related parameters:
                                                                                                            Comments
                                 C
                                        N
                                             Ln
                                                   Exp
                                                          U   Log10U  Emp
                                                                                 SB
   Value
Receptor distance
     from site  [m]
Angle off center                  •
   Set = 0 for  Subtitle  D applications.
Well vertical                     •
   Set = 0 for  Subtitle  D
   distance  [fraction] applications.
Flag to reject wells
                                  Not used in Subtitle  D  outside plume applications.
Times At Which  to  Calculate Concentrations:
            C      =   Constant
            N      =   Normal
            Ln     =   Lognormal
                                                    Not used  in  steady-state
                                                    applications (steady-state
                                                    required  for Subtitle D applications)
                                                   Exp     =   Exponential
                                                   U       =   Uniform
                                                   Log10u  =  Log10Uniform
Emp
SB
G
Empirical
Johnson SB
Gelhar
                                                          71

-------
TABLE 5-10.   PARAMETERS  IN THE UNSATURATED ZONE FLOW  (Funsat)  DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444444
Parameter  [units]   Derived                                  Specified
Default                                                                                                     Comments

                                  C      N    Ln    Exp    u   Log10U  Emp         SB      G      Value

Control Parameters:
Number of porous
     materials
van Genuchten or                                                                                      van
   Brooks/Corey flag                                                                                  Genuchten
Number of physical
   flow layers
Layer Thickness  and  Material for Each Layer:
For 1 layer:
   Depth of the  unsat.
     zone
For >1 layer:
   Thickness  [m]
For >1 layer:
   Material number  of
     layers
Material Properties  (for Each Material) :
Saturated hydraulic
     conductivity  [cm/hr]
Porosity  [--]
            C      =   Constant                     Exp     =   Exponential          Emp     =   Empirical
            N      =   Normal                       U       =   Uniform              SB      =   Johnson SB
            Ln     =   Lognormal                    Log10u =  Log10Uniform           G       =   Gelhar
                                                          72

-------
TABLE 5-10.  PARAMETERS IN THE UNSATURATED  ZONE  FLOW (Funsat)  DATA GROUP (concluded)

                    Derived      _ Specified
Parameter  [units]
Default
Air entry pressure
     head  [m]
C
                                       N
                                             Ln
                                                  Exp
Functional Coefficients  (for  each material) :
   Residual water
     content  [--]
Brooks and Corey                 •••
            Not needed  if van Genuchten  is
            exponent  [--] specified  in control
            parameters
Alpha van Genuchten
     coeff.  [I/cm]
Beta van Genuchten
     coeff.   [--]

            C
            N
            Ln
Constant
Normal
Lognormal
                                                                                                           Comments
                                                         u   Log10U   Emp
                                                                                SB
                                                                                               Value
                  Exp     =   Exponential
                  U      =   Uniform
                  Log10u =  Log10Uniform
                                                                                  Emp
                                                                                  SB
                                                                                  G
                                                                                            Empirical
                                                                                            Johnson SB
                                                                                            Gelhar
                                                         73

-------
When only one layer is modeled, its thickness is equal to the depth of the
unsaturated zone and the depth can be assigned a Monte Carlo distribution.  when
multiple layers are simulated, their thicknesses must be assigned constant values.

Parameters related to material properties and functional relationships must be
specified for each material type being modeled.   All of these parameters can be
assigned a constant value or,  in Monte Carlo mode,  one of seven Monte Carlo
distribution types.  The specification of a Monte Carlo distribution requires
additional data defining the distribution be input  (see Table 5-7).   None of the
Unsaturated Zone Flow Data Group parameters can be derived.

5.3.2.6  Unsaturated Zone Transport Data Group--

The parameters contained in the Unsaturated Zone Transport Data Group are found in
Table 5-11.  All of the parameters listed under "Control Parameters" have default
values associated with them.  The number of layers is defaulted to 1, which
corresponds with the number of layers in the Unsaturated Flow Data Group.  However,
under most conditions the number and thickness of transport  layers need not
correspond to the number and thickness of flow layers.  There are a couple of
restrictions: 1) the sum of the transport layer thicknesses  must equal the sum of
the flow layer thicknesses, and 2) if the depth of the unsaturated zone is assigned
a Monte Carlo distribution in the Unsaturated Zone Flow Data Group  (see Table 5-10),
only one transport layer is allowed.

Unless the modeler has a good understanding of the other "Control Parameters," it is
recommended that the default values be used.

For each transport layer being simulated, five parameters need to be specified.  The
thickness of each layer must be assigned a constant value.  The other four
parameters can have distributions assigned to them in Monte  Carlo mode.  Remember
that the specification of a Monte Carlo distribution requires that additional data
be supplied  (see Table 5-7).  The longitudinal dispersivity  of each layer can be
either specified or derived.  The derivation of this parameter is described in
Section 6.4.2.
                                            74

-------
 TABLE  5-11.
 44444444;
Derived
 Default
             PARAMETERS  IN  THE  UNSATURATED ZONE TRANSPORT  (Tunsat) DATA GROUP
                                      [444444444444
                                       Specified
                                  c
                                        N
                                              Ln    Exp    U   Log10U   Emp
    Number of layers              •
             The number of layers need not
             correspond to the number of
             layers in Unsaturated Flow.
 evaluation
for
             18 is recommended value for
             scheme Stehfest scheme  (the default)
 used           •
 interpolating cones.
Gaussian
 integral
 (for  Each Transport Layer) :
   ))))))))))))))))))))))))))))))
    Thickness of the layer [m]
      dispersivity [m]
      matter
     44444
 Constant
                              Exp
             N     =  Normal
             Ln    =  Lognormal
                                        Exponential
                                                                                SB
                                                                                  18
                                                                                   104
             Emp     =   Empirical
U      =  Uniform               SB
Log10u =  Log10Uniform           G
                                              Parameter  [units]

                                                        Comments

                                             Value
                                              Control Parameters:
                                                                                                    Scheme for
                                                                                                     Stehfest

                                                                                                    Number of terms
                                                 Number of points
                                                        for

                                                 Number of
                                                        points

                                                 Convolution
                                                        segments

                                              Property Parameters
                                                                                                     Longitudinal
                                                                                                     Percent organic
                                                                                             Johnson SB
                                                                                             Gelhar
                                                          75

-------
 TABLE 5-11.   PARAMETERS IN  THE UNSATURATED  ZONE TRANSPORT (Tunsat)  DATA GROUP  (concluded)

Derived      	Specified	
 Default                                                                                                         Comments

                                    C      N     Ln    Exp     u    Log10U  Emp         SB       G       Value

 [g/cc]          •        •          ••••••
 )))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))                    Biological  decay
                •        •          ••••••
      coeff.  [1/yr]

 Constant                       Exp    =   Exponential              Emp     =  Empirical
             N     =  Normal                         U       =   Uniform               SB     =  Johnson SB
             Ln     =  Lognormal                     Log10u =  Log10Uniform            G       =  Gelhar
                                                             76

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                                      SECTION 6


                                PARAMETER ESTIMATION


This  section  is intended to provide  guidance  for estimating parameters  required by
MULTIMED for Subtitle D land disposal facility applications.  It is not intended in any
way to be used as  a  substitute for data collection.   Reported  values  are presented to
demonstrate  appropriate  ranges  of values  for  particular  parameters.    For  easy
reference,  the parameters are grouped according  to  the model data group with which they
are associated.

The most accurate model results will be obtained  from  simulations  which are based on
site-specific  data collection.   In some cases,  however,  it is  not feasible to measure
certain parameters,  and satisfactory results  have been obtained using estimated values.
The code contains  the option to internally  derive some parameters  based on other input
parameters.   It is  recommended that  this option  be used with caution  and only when
values  from measurements  at the site are not available.   The parameters  that can be
derived are identified in this section.   The  methods  used in the  code  to calculate the
derived parameters  are summarized briefly in this section,  and  are discussed in more
detail in the MULTIMED model theory documentation (Salhotra et  al. ,  1990).

There are many sources of uncertainty in the  prediction of  contaminant  migration in the
subsurface.  Utilizing the Monte Carlo option in the  model  is a method  to determine the
effect of  uncertainty  in  the model  input  on the model  results.   In this  option,  a
parameter is assigned a distribution and its  value is then randomly generated.  It is
often  difficult to determine  the  cumulative  probability distribution for  a  given
parameter.   These  distributions must be determined from a large  amount of data,  which
may  not  be  available.    Assuming  a  parameter  probability  distribution when  the
distribution  is unknown does not help reduce uncertainty, as  the certainty of the
output is then  a  function of the assumed certainty  of  the input  parameter (U.S. EPA,
1988) .

Some  guidance on determining  an appropriate  probability  density distribution  for
specific parameters  is provided in this section,  when possible,  tables of descriptive
statistics are  also given.  This information can  be ignored if  the model  is run in a
deterministic  framework.  General information related to the probability distributions
and help in determining the number  of Monte  Carlo runs  needed is provided in Section
9 of the MULTIMED model theory documentation (Salhotra  et al.,  1990).
                                          77

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6.1  CHEMICAL-SPECIFIC PARAMETERS

6.1.1  Overall Chemical Decay Coefficient  (Saturated  Zone)  Fl/yrl

This parameter can be derived by the code,  which  computes  it  by summing the solid and
liquid phase decay coefficients for the saturated  zone.  Note that the overall chemical
decay  coefficient does  not include biological decay;  the  biodegradation coefficient
must be specified separately.  If the value  for the  overall  chemical  decay coefficient
is specified by the user as a constant or a  distribution, the solid and dissolved phase
decay coefficients are not needed.  In general, the overall decay coefficient for the
saturated zone will be smaller in value  than  for the  unsaturated zone.

6.1.2  Solid-Phase and Liquid-Phase Decay  Coefficients (Saturated Zone)  Fl/yrl

These  decay  coefficients  represent the  hydrolysis rate  constants  for  the saturated
zone.   They do not  include biological  decay, which  is  discussed  in  Section  6.1.7.
Hydrolysis is a potentially significant elimination  pathway  for many  organic chemicals
(Lyman et al. ,  1982).  For compounds which are  easily biodegraded,  however,  hydrolysis
may be insignificant relative to biodegradation  (see  Section 6.1.7).   The hydrolysis
of organic chemicals can be described as  a first-order  rate process with respect  to the
concentration of the organic species (Faust  and Gomaa,  1972; Wolfe et al. , 1977;  1978)
and is dependent on temperature,  pH,  adsorption, and the presence of  organic solvents.
Methods for estimating the rate constant for  the hydrolysis  process are presented in
Lyman et al.  (1982) .

The solid-phase and liquid-phase hydrolysis  rate constants  can be derived in the code,
using input for the acid, base, and neutral hydrolysis rate  constants,  the reference
temperature, and the temperature and pH  of the aquifer.  The method used by the code
to derive these parameters is discussed in Section 5.5.2.1 of the MULTIMED model  theory
documentation (Salhotra et al. , 1990).  The use of  acid, base,  and neutral hydrolysis
rates takes into account the strong pH dependence  of  this  process.

If the values of both the solid and dissolved phase decay  coefficients are specified
by the user,  then the saturated transport module  does  not use the values of the acid,
base,  and neutral hydrolysis rate constants. They are  needed,  however,  if unsaturated
transport and/or surface water transport are  also  being simulated.

6.1.3  The Acid-Catalyzed and Base-Catalyzed  Hydrolysis Rates Fl/M-yrl and
       the Neutral Hydrolysis Rate  Fl/yrl

These  three parameters  are used in the  code  to  calculate  the overall  chemical  decay
coefficient  for the  unsaturated,  saturated,   and surface  water modules.   The  use of
these parameters in  the  unsaturated and saturated  transport  modules  is  described in
Section  5.5.2.1 of  Salhotra et al.  (1990).   For the  surface water module,  refer to
Section  6.2.1 of  the same document.  Values  of  these hydrolysis rate  constants are
available in a large number of references, including Lyman  et  al.  (1982),  Mabey  et al.
(1982), and Mills et al.  (1985a) .
                                          78

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6.1.4  Reference Temperature  r°C1

The reference temperature  is  the  temperature  at  which K^b  and  K^r were calculated and
is normally provided along with the hydrolysis rate  constant data.

6.1.5  Distribution Coefficient  (Saturated  Zone)  Fml/gl

Sorption refers to the accumulation of a chemical  in the boundary region of a solid-
liquid interface  (Mills et al., 1985a).  Because sorption  retards chemical  transport
in  the  subsurface,  the  fate of  a  chemical  is  highly  dependent  on  its  sorptive
characteristics  (i.e.,  the distribution  between  the  sorbed  and dissolved phases) .
MULTIMED assumes  that a  linear  equation can describe the relationship  between the
equilibrium  concentrations  of  the   dissolved   and   adsorbed  phases.    The  linear
relationship  requires knowledge of the chemical distribution coefficient,  Kd.   A number
of studies have  developed empirical relationships for the partition  coefficient.   The
relationship  most  suited for relating  the  chemical distribution  coefficient to soil or
porous medium properties is discussed  in detail  by Karickhoff  (1984).

In the absence of  a user-supplied value,  the  chemical  distribution coefficient for the
saturated  zone, Kd, can be derived by the  code.   Hydrophobic  binding is assumed to
dominate the sorption  process and  thus,   the  distribution coefficient is  related
directly to soil organic carbon content using:

   Kd = Kocfoc                                                                     (6.1)

where

   K   = normalized distribution  coefficient  for organic carbon  [mf/g]
    foe
       = '
fraction]
foc = organic carbon content in the saturated zone  [dimensionless
The  estimation of  the normalized  distribution  coefficient  for  organic carbon  is
discussed below.

6.1.6  Normalized Organic Carbon Distribution Coefficient  Fml/gl

The normalized organic carbon distribution  coefficient,  Koc,  is used in  the  code  to
calculate the chemical distribution coefficient  in  the  unsaturated transport  and the
surface water modules.  It is also used in the saturated  transport module  when  the user
chooses  to  derive the chemical distribution coefficient.   There  are many published
lists of values  for  Koc.  Data are available primarily  for  pesticides and,  to  a lesser
degree, aromatic and polycyclic aromatic compounds.   Lyman  et al.  (1982)  recommend ten
different references which contain values of Koc.

If data  on  Koc are not available for a particular chemical, a value can be estimated
from empirical relationships between Koc  and  some  other  property of the  chemical such
as  the water  solubility,  S,  the  octanol-water  partition coefficient,  Kow,  or  the
bioconcentration factor for aquatic life, BCF.   Lyman et  al.  (1982)  tabulate  12 such
regression  equations  obtained  from  data sets of different classes  of chemicals,  and
present guidelines for  selecting an accurate  and  applicable equation for a particular
chemical.   Values  for the  octanol-water partition  coefficient  and   solubility  of
priority pollutants  are available in  many references, including Mabey et al.  (1982)  and
Mills et al.  (1985a) .

6.1.7  Biodegradation Coefficient (Saturated Zone)  n/yrl

Biodegradation,  along with hydrolysis,  is  one of  the  decay  pathways  considered  by
MULTIMED.   For many  contaminants,  biodegradation  is the  most  significant means  of
removal from the subsurface environment.  However, the biodegradation of chemicals  in
the environment  is complex, depending on  a number  of variable  and/or unknown  factors,
such as  the number  of microorganisms  present,  the  availability of  oxygen and  other
nutrients,  and the  pH and temperature  of the system.

A first-order kinetic  relationship is normally used to  represent  biodegradation in the
natural environment. It is difficult  to estimate the  biodegradation  coefficient needed


                                         79

-------
in   this   relationship.  Although   attempts  have  been   made  to  correlate   the
biodegradability  of a compound with its molecular  characteristics,  such as  solubility,
these generalizations are applicable  only to  the  specific chemicals  investigated,  and
are  not recommended  estimation techniques  for other chemicals  (Lyman et  al. ,  1982) .
A significant amount of work is needed to validate  the  extension  of these techniques
to other chemicals and conditions.

A compilation  of laboratory-derived biodegradation rate  constants reported  in  the
literature,  along with the test conditions when available, is presented in Lyman et  al.
(1982).   The tables  include  rate constants  for several  organic compounds  in both
aqueous environments and soils.  However, since these constants  were determined under
laboratory conditions, they may be inapplicable to a  field situation.   Additional data
are available in Mills et al.  (1985a) and Mabey  et  al.  (1982).  Care should  be taken
in extrapolating the results  shown  in  any of these tables to actual  environmental
situations.

6.2  SOURCE-SPECIFIC PARAMETERS

6.2.1  Recharge Rate  Fm/yrl

The  recharge rate  in this  model is the net amount  of water that  percolates  directly
into the aquifer  system outside of the land  disposal  facility.  The  recharge is assumed
to have no  contamination  and hence  dilutes  the  groundwater contaminant  plume.   The
recharge rate into the plume can be calculated in a  variety of ways.   One  possibility
is to  use  a model,  such  as  HELP  (Hydrologic  Evaluation  of  Landfill Performance)
(Schroeder et al. , 1984), without any engineering  controls  (leachate  collection system
or a liner)  to  simulate the water balance for  natural conditions.  Results of such an
analysis have been presented by E.G.  Jordan  Co.  (1985,  1987).

6.2.2  Infiltration Rate Fm/yrl

The infiltration rate is the net amount of leachate that percolates into  the aquifer
system from a land disposal facility.  Because of the use of engineering controls  and
the presence of non-native porous materials  in the landfill  facility,  the infiltration
rate will  typically be different than the  recharge rate.  However,  it can be estimated
by similar methods as those discussed for estimation of the recharge rate.

6.2.3  Area of Waste Disposal Unit  I'm2"!

The  area  of the  waste  disposal unit will vary significantly from site  to site.   The
area should be directly measured and  input by the user.

6.2.4  Length Scale of Facility  [ml

The length of the waste disposal facility should be measured at the site.
However,  this  parameter can  be derived by the code.  The  derivation is based on  the
assumption that the waste disposal facility  has  a square shape.   Therefore,  the code
takes the square root of the area:

   L =  (AJ*                                                                     (6.2)

6.2.5  Width Scale of Facility  Fml

The width of the waste disposal facility should  be  measured at  the  site.
However,  as was true  for the  length scale  of  the facility  (Section 6.2.4), this
parameter  can be  derived by the code,  which  calculates the width of  the facility as  the
square root of the area.
                                          80

-------
6.2.6  Initial Concentration at Waste Disposal Facility  Fmg/11

When possible,  site-specific data should be used.  However, the user should bear  in
mind that concentrations are quite variable over time and thus, a limited  set of  data
may not be representative of conditions at the facility.  If data  are not  available,
a conservative approximation would be the solubility of the contaminant in water.

When using the model for the design of Subtitle D facilities, a value  of  100 times the
Drinking Water Standard can be used  (see Section 5.2.4) .  If the concentration  at the
well (i.e.,  point of compliance)  is at or below the Drinking Water  Standard,  the  design
may prove acceptable.   Since the model response is linear with this  parameter, it  is
convenient to use 1.0 mg/1 as the initial concentration and to calculate  a dilution-
attenuation factor (DAF)  as discussed in Section  5.4.2.

6.2.7  Source Decay Constant  Fl/yrl

The source decay constant  is  used for simulation of an exponentially decreasing (in
time) boundary  condition (see Section 5.2 of Salhotra et  al. ,  1990).   However, the
source is assumed to be constant in Subtitle D applications of MULTIMED.   Therefore,
for Subtitle D applications the preprocessor sets  a default value of  0 for  the  source
decay rate.

6.2.8  Duration of Pulse  Fyrl

The duration of  the contaminant pulse is not required in steady-state applications  of
MULTIMED.   Therefore,  this parameter  does  not  need to be  estimated for  Subtitle  D
applications, which must be steady-state.

6.2.9  Spread of Contaminant Source  [ml

The standard deviation of the gaussian source is a measure of the  spread of  the source.
It can be estimated or derived by the code as:

   O = W/6                                                                      (6.3)

where

   w = the width scale of the facility--!.e., the dimension of the facility  orthogonal
   to the groundwater flow direction  [m]

Dividing by 6 implies that 99.86 percent of the gaussian source spread  is  within the
facility.

6.3  UNSATURATED FLOW PARAMETERS

6.3.1  Saturated Hydraulic Conductivity  Tcm/hrl

Hydraulic conductivity expresses the ease with which a fluid can be transported through
a porous medium  and is a function of properties of both the porous  medium  and the fluid
(Mills et al.,  1985b).   Note that for some materials,  such as alluvium, the vertical
hydraulic  conductivity  is  significantly  smaller  than  the  horizontal  hydraulic
conductivity.   Mills  et  al.   (1985b) state that  the  ratio of horizontal to vertical
conductivity is  from 2 to 10 for alluvium and glacial outwash and from 1.5 to 3 for
sandstone.  In  the unsaturated  zone module,  flow is one-dimensional in the vertical
direction, so the vertical hydraulic conductivity should be input.   Note  that  in the
saturated zone,  the horizontal hydraulic conductivity  is required.

One of the most widely-used  tables  of hydraulic  conductivity values is presented  in
Table 6-1.   Note that the use of the values in this table will require a  conversion  to
the units of cm/hr.  In addition, descriptive statistics for a variety  of  soil types
are given in Table 6-2.   The values  for the coefficients of variation in column three
are determined  from  many soils nationwide which  fall  into each texture group.  The
coefficient of variation for a single soil is likely to be lower.

The lognormal distribution is likely to be an appropriate probability  density function


                                         81

-------
for saturated hydraulic conductivity  (Dean et al.,  1989)
                                         82

-------
Table 6-1    (Graphic)
                                          83

-------
TABLE 6-2.  DESCRIPTIVE STATISTICS  FOR  SATURATED HYDRAULIC CONDUCTIVITY
             (cm hr"1)
4444444444444444444444444444444444444444444444444444444444444444444444
                              _       Hydraulic  Conductivity (Ks)*
Soil Type                     x              s              CV            n
Clay**                        0.20          0.42         210.3         114

Clay Loam                     0.26          0.70         267.2         345

Loam                          1.04          1.82         174.6         735

Loamy Sand                   14.59         11.36          77.9         315

Silt                          0.25          0.33         129.9          88

Silt Loam                     0.45          1.23         275.1        1093

Silty Clay                    0.02          0.11         453.3         126

Silty Clay Loam               0.07          0.19         288.7         592

Sand                         29.70         15.60          52.4         246

Sandy Clay                    0.12          0.28         234.1          46

Sandy Clay Loam               1.31          2.74         208.6         214

Sandy Loam                    4.42          5.63         127.0        1183
                    _
   n  =  Sample size,  x = Mean, s = Standard deviation,  CV =  Coefficient of
   variation  (percent)

  Agricultural soil,  less  than  60 percent clay

Sources:  From Dean et al .  (1989),
          Original reference  Carsel  and  Parrish (1988).
6.3.2  Unsaturated Zone  Porosity  F--1

Porosity is a measure of  the relative volume of void space  in  a rock or soil.  Porosity
is dimensionless and is  expressed  as  a  fraction or a percentage.  The total porosity
of a rock or soil  is comprised of primary porosity,  which is due to the shape, sorting
and  packing of the grains  in the  matrix,  and  secondary porosity,  which  is  due to
phenomena such as cracks and  fractures.

MULTIMED requires  the effective porosity of the rock or soil as input.  The effective
porosity is that part of  the total  porosity which is effective at transmitting water.
The effective porosity  is typically lower than the total porosity, due to the presence
of pores which are not interconnected or the
presence  of an immobile water film  bound to  soil  grains.   In  general,  laboratory
measurements obtain values for total  porosity,  since effective porosity is difficult
to measure directly.

Typical total  porosity values for  a  variety of geologic  materials  are  presented in
Table 6-3.   Jury  (1985) states that a normal distribution is an appropriate probability
density function for effective porosity.

6.3.3  Air Entry Pressure Head  [ml

The air entry pressure  head is the threshold at which air starts to penetrate saturated
soil.  It is typically  a  very  small  negative value for fine-grained materials or zero
for  coarser soils.   Its value  can be  estimated from the water  retention curves of
specific soils (Freeze and Cherry,  1979) .
                                          84

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6.3.4  Number of Layers, Thickness  of  Layers [ml

The unsaturated zone extends  from the  land surface or the bottom of a waste disposal
facility to the top of  the water  table.    This  distance will vary significantly  from
site  to site.    An estimate of this  depth  can be  determined  from  water level
measurements in the area of the site.
TABLE 6-3.  TOTAL POROSITY  OF VARIOUS  MATERIALS

4444444444444444444444444444444444444444444444444444444444444444444444

                            No.  of                                 Arithmetic
Material                   Analyses           Range                  Mean
Igneous Rocks
  Weathered granite           8             0.34-0.57                 0.45
  Weathered gabbro            4             0.42-0.45                 0.43
  Basalt                     94             0.03-0.35                 0.17

Sedimentary Materials
  Sandstone                  65             0.14-0.49                 0.34
  Siltstone                   7             0.21-0.41                 0.35
  Sand  (fine)               243             0.26-0.53                 0.43
  Sand  (coarse)              26             0.31-0.46                 0.39
  Gravel  (fine)              38             0.25-0.38                 0.34
  Gravel  (coarse)            15             0.24-0.36                 0.28
  Silt                      281             0.34-0.61                 0.46
  Clay                       74             0.34-0.57                 0.42
  Limestone                  74             0.07-0.56                 0.30

Metamorphic Rocks
  Schist                     18             0.04-0.49                 0.38


Sources:  From Mercer et  al .  (1982),
          Mcwhorter and Sunada (1977) ,
          Original reference Morris  and Johnson,  (1967).
                                          85

-------
In MULTIMED,  the unsaturated  zone  can be modeled  with up to  20  layers which  have
distinct  physical  characteristics.    Information  about the layers,  which should  be
relatively homogeneous and distinguishable  from adjacent  layers,  must  be  determined  on
a site-specific basis.  Note that more than one layer can be assigned the  same  material
properties,   when one homogeneous layer is  modeled, the layer thickness is equal  to the
depth of the unsaturated zone and the depth of the unsaturated  zone  can have a Monte
Carlo distribution assigned to it.  Refer  to Section 6.4.1 for  more  information.

6.3.5  Residual Water Content  F--1

The residual  water content is that amount  of the total water content  which can  not  be
removed  from the soil,  even under large suction pressure, because it adheres  to the
soil  grains.   Descriptive statistics  for residual water content for  a  variety  of types
of soils  are presented  in  Table 6-4.  In addition,  the residual water  content for a
large number  of soils can be estimated using the interactive computer program,  DBAPE,
which  is  a soils data base analyzer  and  parameter  estimator  (Imhoff et al.,  1990).
DBAPE  is  available from the  U.S.  EPA Center  for  Environmental Assessment  Modeling
(CEAM) at the Environmental Research Laboratory in Athens, Georgia.

6.3.6  Brooks and Corey Exponent  F--1

The Brooks and Corey exponent, n, is an empirical parameter used in an equation which
describes  the relationship between relative permeability and water  saturation  (see
Section 3.2 of the MULTIMED model theory documentation  (Salhotra et al.,  1990)).  The
exponent  can be  determined from experimental data  for  a soil's capillary pressure-
desaturation  curve.  Brooks and Corey  (1966) present experimental results  for several
porous media.  The  porous  media investigated by the authors had values  of n ranging
from 3.27 for glass beads to 4.11 for a silt loam.  Soils composed of single-grained
material  with no  secondary porosity (e.g.,  sands) tend to have smaller  exponent values.
Soils with structure or secondary porosity have larger  exponent values.

In MULTIMED,  the relationship between relative permeability and water saturation may
be described using either the  Brooks  and Corey  (1966)  or  the  van  Genuchten  (1976)
relationship  (see Section 3 of Salhotra et  al.  (1990)).   The Brooks  and Corey  exponent
is not required  when the use of the  van  Genuchten  relationship is  specified  in the
input.  However,  both the Brooks and Corey exponent and the van Genuchten parameters
are required when the use of the Brooks and Corey relationship  is  specified.

6.3.7  Van Genuchten Parameters, a  Fl/cml  ; B  F--1

In the code,  the relationship between relative permeability and water saturation may
be described using either the  Brooks  and Corey  (1966)  or  the  van  Genuchten  (1976)
relationship.   However,  the pressure  head versus  water  saturation relationship  is
described using van Genuchten parameters  (see Section 3 of the  MULTIMED model  theory
documentation (Salhotra et al. , 1990)).  Therefore, the  van Genuchten parameters  must
be input to  simulate unsaturated flow in  the code.  Descriptive statistics for these
empirical parameters have been reported by  Carsel and Parrish  (1988)  for a variety  of
soil  types (see Table 6-5)  .
                                         86

-------
TABLE 6-4.  DESCRIPTIVE  STATISTICS  FOR SATURATION WATER CONTENT  (6J
            AND RESIDUAL WATER  CONTENT (6r)
4444444444444444444444444444444444444444444444444444444444444444444444
                    Saturation Water Content  (6J    Residual Water Content  (6r)
                                          Statistic*
Soil  Type
CV
                                              n
                                                                      CV
                                                                             n
Clay"

Clay Loam
Loam

Loamy Sand

Silt

Silt Loam

Silty Clay

Silty Clay Loam

Sand

Sandy Clay

Sandy Clay Loam

Sandy Loam
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.38
.41
.43
.41
.46
.45
.36
.43
.43
.38
.39
.41
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.09
.09
.10
.09
. 11
.08
.07
.07
.06
.05
.07
.09
24 .
22.
22.
21.
17 .
18.
19.
17 .
15.
13.
17.
21.
. 1
.4
. 1
.6
.4
. 7
.6
.2
. 1
. 7
. 5
.0
400
364
735
315
82
1093
374
641
246
46
214
1183
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.068
.095
.078
.057
.034
.067
.070
.089
.045
.100
.100
.065
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.034
.010
.013
.015
.010
.015
.023
.009
.010
.013
.006
.017
49.
10.
16.
25.
29.
21.
33.
10.
22 .
12.
6.
26.
.9
. 1
. 5
. 7
.8
.6
. 5
.6
.3
.9
.0
.6
353
363
735
315
82
1093
371
641
246
46
214
1183
                    _
   n  =  Sample size,  x = Mean, s = standard  deviation,  CV = coefficient of
       variation  (percent)

  Agricultural  soil,  less  than  60  percent clay.

Source: Dean et al .  (1989)
        Original  source Carsel  and  Parrish  (1988)


6.4  UNSATURATED  TRANSPORT  PARAMETERS

6.4.1  Number of  Layers, Thickness  of  Layers

The number of layers  specified for transport in the unsaturated  zone will depend on  the
specific  conditions  present  at the site.   Layers  should represent  zones  that  are
relatively homogeneous with  regard  to the properties affecting transport and that  can
be distinguished  from adjacent  layers  by changes in these properties.  Note that  the
number and thickness of layers  specified in the  transport module need not correspond
to the  number  and thickness of layers  in  the unsaturated  flow  module (see Section
6.3.4).   However,  the  sum of the individual  layer thicknesses in the two modules must
equal each other (i.e., the  total depth of the unsaturated zone must agree in the  two
modules) .   If the  depth of the unsaturated zone is assigned a Monte Carlo distribution
in the unsaturated flow module,  then only one  unsaturated transport layer is allowed.
                                          87

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Table 6-5.  DESCRIPTIVE STATISTICS  FOR  VAN GENUCHTEN WATER RETENTION MODEL PARAMETERS,  a,  3,  and Y (Carsel  and
                   Parrish  1988)
Parameter a.
Parameter
Soil
Claya
Clay
Loam
Loamy
Silt
Silt
Silty
Silty
Sand
Sandy
Sandy
Sandy
Type

Loam

Sand

Loam
Clay
Clay Loam

Clay
Clay Loam
Loam
X = Mean, SD = Standard

0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
X
.008
.019
.036
.124
.016
.020
.005
.010
. 145
.027
.059
. 075

0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
Deviation, CV =
SD
012
015
021
043
007
012
005
006
029
017
038
037
Y
cm

CV
160.
77 .
57 .
35.
45 .
64.
113.
61.
20.
61.
64.
49.
.3
.9
. 1
.2
.0
. 7
.6
. 5
.3
. 7
.6
.4
Coefficient
-i

N
400
363
735
315
88
1093
126
641
246
46
214
1183
Parameter

1.
1.
1.
2.
1.
1.
1.
1.
2.
1.
1.
1.
of Variation
X
.09
.31
.56
.28
.37
.41
.09
.23
.68
.23
.48
.89
SD
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.09
.09
.11
.27
.05
.12
.06
.06
.29
.10
.13
. 17
(percent) ,
CV
7.9
7.2
7.3
12.0
3.3
8.5
5.0
5.0
20.3
7.9
8.7
9.2
N =
N
400
364
735
315
88
1093
374
641
246
46
214
1183
Sample

0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
size
3
X
08
24
36
56
27
29
09
19
62
18
32
47


SD
0.07
0.06
0.05
0.04
0.02
0.06
0.05
0.04
0.04
0.06
0.06
0.05



CV
82.
23.
13.
7 .
8.
19.
51.
21.
6.
34.
53.
10.

. 7
. 5
. 5
. 7
.6
.9
. 7
. 5
.3
. 7
.0
.1

N
400
364
735
315
88
1093
374
641
246
46
214
1183

 Agricultural Soil,  Clay 60 percent

-------
6.4.2  Longitudinal Dispersivity of Each Layer  [ml

Hydrodynamic dispersion refers to the spreading and mixing caused by molecular
diffusion and mechanical dispersion (Freeze and Cherry, 1979).  For many  field
problems, molecular diffusion is small relative to mechanical dispersion  and can be
ignored.  Molecular diffusion is not considered in MULTIMED, which calculates the
longitudinal dispersion coefficient as the product of the seepage velocity and
longitudinal (aL)  dispersivity.   Note  that  longitudinal  dispersion is  the dispersion
in the predominant direction of flow,  which is vertical in the unsaturated zone.

Dispersivity is a difficult parameter to determine.  Table 6-6 provides a compilation
of dispersivity values appropriate for the unsaturated transport module.  Research
has shown that the values for longitudinal dispersivity are  scale dependent.  In an
unsaturated transport layer, if a value for the longitudinal dispersivity is not
input, the user can specify that the parameter be derived.   The equation  used in the
model to calculate dispersivity is based on regression analysis of the data in Table
6-6.  The following relationship between dispersivity and the depth of the
unsaturated zone, L, was developed:

         av  =  0.02 +0.022L,       R2 =  66%                                         (6.4)

To avoid excessively high values of dispersivity  for deep unsaturated zones, a
maximum dispersivity of 1.0 m is used.

Distributional properties for longitudinal dispersivity are  unknown (Dean et al.,
1989) .

6.4.3  Percent Organic Matter [--1

Guidance in estimating the percent organic matter is provided in Table 6-7.  Values
are given for the four Hydrologic Soil Groups and for four ranges of depth.  From
Appendix B of the users manual for PRZM, Release  I  (Carsel et al., 1984)  or from
Section 4 of the  SCS National Engineering Handbook  (Soil Conservation Service, 1972),
the hydrologic soil group for the particular soil that is in the area under
consideration can be found.  There are four different soil classifications  (A, B, C,
and D) ,  and they  are in the order of decreasing percolation  potential and increasing
slope and runoff  potential.  Soil characteristics associated with each hydrologic
group are as follows:

       Group A:    Deep sand, deep loess,  aggregated silts,  minimum infiltration of
                   0.76 - 1.14 (cm hr"1)

       Group B:    Shallow loess, sandy loam, minimum infiltration 0.38 - 0.76  (cm
                   hr-1)

       Group C:    Clay loams, shallow sandy loam, soils low in organic content, and
                   soils usually high in clay, minimum infiltration 0.13  - 0.38  (cm
                   hr-1)

       Group D:    Soils that swell significantly when wet,  heavy plastic clays, some
                   saline soils,  minimum infiltration 0.03 - 0.13  (cm hr"1)
                                          89

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TABLE  6-6.   COMPILATION OF  FIELD DISPERSIVITY VALUES
44444444444444444444444444444444444444444444444444444444444444444444444
(1976)
                                                                  Longitudinal
Author
Yule and Gardner
(1978)
Hildebrand and
Himmelblau (1977)
Kirda et al .
(1973)
Gaudet et al .
(1977)
Brissaud et al .
(1983)
Warrick et al .
(1971)
Van de Pol et al .
(1977)
Biggar and Nielsen
Type of Vertical Scale Dispersivity
Experiment of Experiment (m) av (m)
Laboratory
Laboratory
Laboratory
Laboratory
Field
Field
Field
Field
0.23
0.79
0.60
0.94
1.00
1.20
1.50
1.83
0.0022
0.0018
0.004
0.01
0.0011,
0.002
0.027
0 . 0941
0.05
Kies (1981)
Jury et al . (1982)
Andersen et al .
(1968)
Oakes (1977)
Field
Field
Field
Field
2.00
2.00
20.00
20.00
0.168
0 . 0945
0.70
0.20
  From Dean  et al.   (1989),
  Original reference Gelhar  et al.  (1985).
                                              90

-------
TABLE 6-7.  DESCRIPTIVE STATISTICS AND  DISTRIBUTION MODEL FOR ORGANIC
            MATTER (PERCENT BY WEIGHT)
44444444444444444444444444444444444444444444444444444444444444444444444
Stratum

(m)
Class A
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2

Class B
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2

Class C
  0.0-0.3
  0.3-0.6
  0.3-0.9
  0.9-1.2

Class D
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2
Sample

 Size
 162
 162
 151
 134
1135
1120
1090
1001
 838
 822
 780
 672
 638
 617
 558
 493
                                    Original  Data


Mean
)))))))))))
0
0
0
0

0
0
0
1
0
0
0
1
0
0
0
.86
.29
.15
.11
1.3
.50
.27
.18
.45
.53
.28
.20
.34
.65
.41
.29


Median
')))))))))))}
0
0
0
0

0
0
0
1
0
0
0
1
0
0
0
.62
.19
.10
.07
1. 1
.40
.22
. 14
.15
.39
.22
. 15
.15
.53
.32
.22

s .
1)))))
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
0.
0.
0.
0.
0.
0.

.d.
))))))]
.79
.34
. 14
.11
.87
.40
.23
.16
. 12
.61
.27
.21
.87
.52
.34
.31
CV
(%)
))))))))))
92
114
94
104
68
83
84
87
77
114
96
104
66
80
84
105
                                                Distribution Model
Mean
-4 .
-5 .
-6.
-6.
-4 .
-5 .
-5.
-6.
-3.
-5 .
-5.
-6.
-4 .
-4 .
-5.
-5 .
.53
.72
.33
.72
.02
.04
.65
.10
.95
.08
.67
.03
.01
.79
.29
.65
S .
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.d.
.96
.91
.83
.87
.76
. 77
.75
.78
.79
.84
.83
.88
.73
.78
.82
.86
CV   = coefficient  of variation
s.d. = standard  deviation
Source:  Dean  et al.  (1989), Original  reference Carsel et al.  (1988;
a  Johnson SB  transformation  is used  for all cases in this table.
                                           91

-------
Carsel et al.  (1988) state that a Johnson SB distribution is most appropriate for the
data in Table 6-7.  Note that the percent organic matter typically decreases with
depth.  More detailed data on percent organic matter are available through the
interactive computer program DBAPE discussed in Section 6.3.5  (Imhoff et al., 1990).

If the percent organic matter is not known, but the fractional organic carbon content
is given, the following equation can be used to estimate the percent organic matter:

         fom = 172.4 foc                                                           (6.5)

where

         foc    = fractional organic carbon content  [dimensionless]
         fom    = percent organic matter  [dimensionless]
         172.4 = conversion factor from percent organic matter content to
              fractional organic carbon content

6.4.4  Bulk Density of Soil for Layer  [g/ccl

Bulk density can be defined as the mass of a unit volume of dry soil  (Mercer et al.,
1982).  The soil bulk density directly influences the retardation of solutes and is
related to the structure and texture of a soil.  The bulk density of soils typically
range between 1.3 and 2.0 g/cc, but Mercer et al.  (1982) state that the bulk density
can be as low as 0.3 g/cc for soils high in organics or aluminum and iron hydroxides.
Representative values for five different types of soils are shown in Table 6-8.  In
addition, values of bulk density for a large number of soils can be obtained from
DBAPE, discussed in Section 6.3.5  (Imhoff et al.,  1990).

Descriptive statistics for bulk density are given in Table 6-9 for the four
Hydrologic Soil Groups (A, B, C, and D) and for four ranges of depth.  (A brief
description of the soil groups in given in Section 6.4.3.)   The most appropriate
probability density distribution for bulk density is typically a normal distribution
(Jury, 1985) .

6.4.5  Biological Decay Coefficient  n/yrl

Estimation of the biodegradation rate constant is discussed in Section 6.1.7.

6.5  AQUIFER-SPECIFIC PARAMETERS

6.5.1  Aquifer Porosity  F--1

Porosity is also discussed in Section 6.5.1 and values of porosity for various
materials are given in Table 6-3.  It is an important parameter, influencing the
velocity and retardation of contaminants transported in an aquifer (Mills et al. ,
1985b).   In the absence of a user-specified distribution for the aquifer porosity,  it
can be derived by the code.  It is calculated from the particle diameter using the
following empirical relationship (Federal Register Vol. 51, No. 9, p. 1649, 1986):
                                          92

-------
TABLE 6-8.  MEAN BULK  DENSITY (g/cm3)  FOR  FIVE  SOIL TEXTURAL
            CLASSIFICATIONS3'1"
44444444444444444444444444444444444444444444444444444444444444444444444

Soil Texture                       Mean Value                  Range Reported
)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
Silt Loams                             1.32                       0.86  -  1.67

Clay and Clay Loams                    1.30                       0.94-1.54

Sandy Loams                            1.49                       1.25-1.76

Gravelly Silt Loams                    1.22                       1.02-1.58

Loams                                  1.42                       1.16-1.58

All Soils                              1.35                       0.86  -  1.76
  Baes,  C.F.,  III and R.D. Sharp.   1983.  A  Proposal  for Estimation of
  Soil Leaching  Constants for Use in Assessment Models.  J. Environ.
  Qual. 12(1): 17-28  (Original reference).

  From Dean et al .  (1989)
         6 = 0.261  -  0.0385  In (d)                                                 (6.6)

where d is the mean particle diameter [cm] .

6.5.2  Particle Diameter  Fcrnl

The particle diameter can  be determined by methods such as sieve  analysis  (Freeze  and
Cherry, 1979) .  Table 6-10 shows the range of soil particle sizes   for  a variety of
soil materials.   If the porosity is known,  the particle diameter  can  be derived using
Equation 6.6.  Note that both porosity and particle diameter can  not  be derived in
the same simulation (i.e.,  at least one must be input by the user).

6.5.3  Bulk Density Fg/ccl

Bulk density is discussed  in Section 6.4.4 and Tables 6-8 and 6-9 provide  data on  the
bulk density of soils.  However,  the bulk density of aquifer materials  may differ
significantly from  that of soils.   Therefore, data on the ranges  of bulk density for
various geologic  material  are presented in Table 6-11.

If site-specific  data are  not available,  the bulk density of the  saturated zone can
be derived by the model using an exact relationship between porosity, particle
density and the bulk  density (Freeze and Cherry, 1979) .   Assuming the particle
density to be 2.65  g/cc, this relationship can be expressed as:
                                           93

-------
Table 6-9.   DESCRIPTIVE STATISTICS  FOR BULK DENSITY  (g  cm"3)
44444444444444444444444444444444444444444444444444444444444444444444444
Stratum            Sample
   (m)              Size            Mean         Median        s.d.
Class A
                                                                             CV
                                                                             (%)
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2
                      40
                      44
                      38
                      34
1.45
1.50
1.57
1.58
1.53
1.56
1.55
1.59
0 .24
0.23
0.16
0.13
16.2
15.6
10.5
8.4
Class B
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2
                     459
                     457
                     438
                     384
1.44
1.51
1.56
1.60
1.45
1.53
1. 57
1.60
0.19
0.19
0.19
0.21
13.5
12 .2
12.3
12 . 9
Class C
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2
                     398
                     395
                     371
                     326
1.46
1.58
1. 64
1.67
1.48
1.59
1.65
1.68
0 .22
0.23
0.23
0.23
15.0
14 . 5
14 .2
14 . 0
Class D
  0.0-0.3
  0.3-0.6
  0.6-0.9
  0.9-1.2
                     259
                     244
                     214
                     180
1.52
1.63
1.67
1.65
1.53
1.66
1.72
1. 72
0.24
0.26
0.27
0.28
15.9
16.0
16.3
17.0
CV   = coefficient of variation
s.d. = standard deviation

Sources:  From Dean et al .   (1989),
          Original reference Carsel  et al .  (1988)
                                            94

-------
TABLE 6-10.  RANGE OF SOIL  PARTICLE  SIZES  FOR VARIOUS MATERIALS

44444444444444444444444444444444444444444444444444444444444444444444444
            	Size Range	               Approximate Sieve Mesh
Openings
Class name
 Millimeters
 Inches
Tyler  United States Standard
Very large boulders  4,096-2,048
Large boulders
Medium boulders
Small boulders
Large cobbles
Small cobbles

Very coarse gravel
Coarse gravel
Medium gravel
Fine gravel
Very fine gravel

Very coarse sand
Coarse sand
Medium sand
Fine sand
Very fine sand

Coarse silt
Medium silt
Fine silt
Very fine silt

Coarse clay
Medium clay
Fine clay
Very fine clay
 2,048-1,024
   1,024-512
    512-256
    256-128
    128-64

     64-32
     32-16
     16-8
     8-4
     4-2

 2.000-1.000
 1.000-0.500
 0.500-0.250
 0.250-0.125
 0.125-0.062

 0.062-0.031
 0.031-0.016
 0.016-0.008
 0.008-0.004

 0.004-0.0020
0.0020-0.0010
0.0010-0.0005
0.0005-0.00024
Modified from Vanoni  (1975).
  160-80
  80-40
  40-20
  20-10
   10-5
  5-2.5

 2.5-1.3
 1.3-0.6
 0.6-0.3
 0.3-0.16
0.16-0.08
2-1/2
  5
                  16
                  32
                  60
                  115
                  250
               5
               10

               18
               35
               60
              120
              230
                                                                        Reference:
         pb = 2.65 (1 - 6)                                                          (6.7)

where pb =      the  bulk density  of  the  soil  [g/cc].

6.5.4  Aquifer Thickness  [ml

The estimation of the thickness  of  the  aquifer is site-specific, and should be based
on available geologic data.

6.5.5  Source Thickness  (Mixing  Zone  Depth)  [ml

Percolation of water  through  the facility (and unsaturated zone, if it exists)
results in the development  of a  contaminant  plume below the facility (see Figure
6.1).  The thickness, H,  of this plume  depends on the vertical dispersivity of the
media.  If a value  for H  is not  known,  it can  be derived in the model using the
following relationship:
                                          95

-------
TABLE 6-11.   RANGE  AND MEAN VALUES OF  DRY BULK DENSITY FOR  VARIOUS  GEOLOGIC
               MATERIALS
4444444444444444444444444444444444444444444444444444444444444444444444444444
Material                                   Range  (g/cm3)        Mean  (g/cm3)
Clay
Silt
Sand, fine
Sand, medium
Sand, coarse
Gravel, fine
Gravel, medium
Gravel, coarse
Loess
Eolian sand
Till, predominantly silt
Till, predominantly sand
Till, predominantly gravel
Glacial drift, predominantly silt
Glacial drift, predominantly sand
Glacial drift, predominantly gravel
Sandstone, fine grained
Sandstone, medium grained
Siltstone
Claystone
Shale
Limestone
Dolomite
Granite, weathered
Gabbro, weathered
Basalt
Schist
Reference: Morris and Johnson (1967)
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
2 .
1.
1.
1.
1.
1.
1.
.18
.01
.13
.27
.42
.60
.47
.69
.25
.33
.61
.69
. 72
. 11
.36
.47
.34
.50
.35
.37
.20
.21
.83
.21
.67
.99
.42
; Mills
-1.
-1.
-1.
-1.
-1.
-1.
-2.
-2.
-1.
-1.
-1.
-2.
-2 .
-1.
-1.
-1.
-2 .
-1.
-2.
-1.
-2 .
-2 .
-2.
-1.
-1.
-2 .
-2.
et
72
79
99
93
94
99
09
08
62
70
91
12
12
66
83
78
32
86
12
60
72
69
20
78
77
89
69
al.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
2 .
1.
2.
1.
1.
2 .
1.
(1985b)
.49
.38
. 55
.69
.73
.76
.85
.93
.45
.58
.78
.88
.91
.38
. 55
.60
.76
.68
.61
.51
.53
.94
.02
.50
.73
.53
.76


-------
Figure 6 .1
                                          97

-------
H = (2av
                     + B(l - exp
(6.8)
where
         av  =  the vertical dispersivity  [m]
         L   = the length scale of the facility--!.e., the dimension of the  facility
               parallel to the flow direction  [m]  (if L is not known, an estimate can
               be obtained from Equation 6.2)
         B   = the thickness of the saturated  zone  [m]
         Vs  =  one-dimensional, uniform seepage velocity in the x direction  [m/yr]
         Qf  =  percolation rate  [m/yr]

In Equation 6.8 the first term represents the  thickness of the plume due to  vertical
dispersion and the second term represents the  thickness of the plume due to  the
vertical velocity below the facility resulting from percolation.  While implementing
this alternative, the code checks that the computed value of the thickness of the
source, H, is not greater than the thickness of the aquifer, B.  If it is, the source
thickness is set equal to the aquifer thickness.

6.5.6  Hydraulic Conductivity  Tm/yrl

Hydraulic conductivity estimates should be based on site-specific data collection,
such as piezometer tests  (bail tests or slug tests) and/or pumping tests.  Some
typical hydraulic conductivity values for various materials are shown in Tables 6-1
and 6-2 and discussed in Section 6.3.1.  Note  that the units of hydraulic
conductivity are m/yr in the saturated zone, but cm/hr elsewhere in the code.

An alternative, though often a poor one, is to allow the code to derive a value for
hydraulic conductivity.  The code uses an approximate functional relationship, the
Kozeny-Carman equation (Bear 1979) :
K =
                                                                                 (6.9)
where

         K   = the hydraulic conductivity  [cm/s]
         p   = the density of water  [kg/m3]
         g   = acceleration due to gravity  [m/s2]
         u   = the dynamic viscosity of water  [N-s/m2]
         d   = mean particle diameter  [cm]

In Equation 6.9, the constant 1.8 includes a unit conversion factor.  Both the
density of water, p, and the dynamic viscosity of water, u, are functions of
temperature and are computed using regression equations presented in CRC  (1981)
Note that at 15°C,  the value of [pg/1.8u]  is about 478.
                                          98

-------
6.5.7  Hydraulic Gradient  I'm/ml

The hydraulic gradient is the change in water level elevation over a given distance.
In general, it is a function of the local topography,  groundwater recharge volume and
location, and the volume and location of groundwater withdrawals.  Further, it may
also be related to the porous media properties.

The gradient can often be estimated from water level measurements in the area
surrounding the site or from a map of water table or potentiometric surface
elevations.  The average gradient under natural conditions should be input in the
model.  Therefore estimates should not include the effect of pumping.  The data used
to estimate the hydraulic gradient can also be used to determine the direction of
groundwater flow.
6.5.
Groundwater Seepage Velocity Tm/vrl
The groundwater velocity is needed to quantify transport by advection.  Because
groundwater velocities are difficult to measure directly, they are often determined
indirectly, using the fact that seepage velocity is related to the aquifer properties
through Darcy's Law.  Assuming a uniform, saturated porous medium, the seepage
velocity can be expressed as:
         vs  =  KS/6                                                               (6.10)
where
         K   = the hydraulic conductivity of the formation  [m/yr]
         S   = the hydraulic gradient  [m/m]

MULTIMED allows the user to derive the seepage velocity by means of Equation 6.10
instead of directly entering a value.

Note that the hydraulic conductivity of the aquifer is used by the code only to
calculate the seepage velocity.  Therefore,  if the groundwater seepage velocity is
specified by the user, the hydraulic conductivity will not be used.
6.5.
Retardation Coefficient F--1
The retardation factor is used to determine the retardation, due to adsorption, of a
contaminant relative to the bulk mass of water transporting the contaminant  (Freeze
and Cherry, 1979).   In addition to delaying the arrival time of a contaminant at a
receptor, retardation together with dispersion can lower the peak concentration.  In
MULTIMED, the retardation factor can be input directly or derived by the code using:
                                                                                (6.11)
where
         pb   =  bulk  density  [g/cc]
         K   = contaminant distribution coefficient  [cc/g]
         6   = saturation water content [--]

Estimation of the bulk density, distribution coefficient, and saturation water
content has been discussed in earlier sections.  Note that a value of one for the
retardation coefficient means that the contaminant does not interact with the solid
phase, but acts as a conservative tracer.   An example of a conservative tracer is
chloride.
                                          99

-------
6.5.10  Longitudinal, Transverse and Vertical Dispersivities  [ml

The aquifer longitudinal  (aL) ,  transverse (aT), and vertical  (av) dispersivities are
used in the model to calculate hydrodynamic dispersion  (i.e.,  the  spreading  and
mixing caused by mechanical dispersion).  The spreading of a  contaminant  caused by
molecular diffusion is assumed to be small relative to mechanical  dispersion and  is
ignored in the model.  The estimation of longitudinal dispersivity in  the unsaturated
zone is discussed in Section 6.4.2.  Note that the longitudinal dispersivity is
oriented in the vertical direction for  the unsaturated zone,  while it  is  oriented in
the horizontal direction for the saturated zone.

The values for dispersivity are difficult to determine.  Research  has  shown  that  the
values for these parameters are strongly scale dependent  (EPRI, 1985).  This can  be
seen in Figure 6.2.  In general, dispersion is determined by  adjusting the
dispersivity values until modeling results match historical data  (Mercer  et  al.,
1982) .

In the absence of user-specified values, the model allows two alternatives for
deriving the aquifer dispersivities.  Alternative one is based on  values  presented in
Gelhar and Axness  (1981).  Dispersivities are calculated as a fraction of the
distance to the downgradient receptor well, as follows:

         «L  =  0 .1  xr                                                             (6.12)

         aT  =  aL/3.0                                                             (6.13)

         av  =  0.056aL                                                            (6.14)

where xr  is  the  distance to the receptor well  [m].   This option is summarized in
Table 6-12(a).

Alternative two allows a probabilistic  formulation for the longitudinal dispersivity
as shown in Tables 6-12 (a) and 6-12 (b)  [Gelhar  (personal communication),  1986] .   The
longitudinal dispersivity is assumed to be uniform within each of  the  three  intervals
shown in Table 6-12(b).  Note that these values of longitudinal dispersivity shown
are based on a receptor well distance of 152.4 m.  For other  distances, the  following
equation is used:

         «L(xr) = «L(xr = 152.4) (xr/152.4)0'5                                       (6.15)

The transverse and vertical dispersivity are assumed to have  the  following values:
                                          100

-------
Figure 6.2
                                         101

-------
TABLE  6-12(a).  ALTERNATIVES  FOR INCLUDING DISPERSIVITIES  IN THE
                     SATURATED  ZONE MODULE
4444444444444444444444444444444444444444444444444444444444444444444444444444
Dispersivitv
      Alternative  1            Alternative 2
Existing Values    Gelhar's  Recommendation
«L [m]
Formulation
«T [m]
av [m]
aL/aT
aL/av
0 . 1 xr Probabilistic
(See Table 5-3 (b) )
0.333 «L Oij8
0.056 «L «L/160
3 8
approx. 18 160
TABLE  6-12(b).     PROBABILISTIC REPRESENTATION OF  LONGITUDINAL DISPERSIVITY
   FOR A DISTANCE  OF 152.4  m
4444444444444444444444444444444444444444444444444444444444444444444444444444
«L (m)               0.1-1

Probability        0.1

Cumulative         0.1
Probability
                  1-10

                  0.6

                  0.7
10-100

0.3

1.0
                                             102

-------
   «T =  aL/8                                                                     (6.16)

   av =  aL/l60                                                                   (6.17)

The distributional properties for the longitudinal and transverse dispersivities are
unknown  (Dean et al.,  1989).

6.5.11  Aquifer Temperature  r°C1

This parameter is site-specific and should be measured at the site.  Note that
MULTIMED does not take into account any seasonal variation in temperature in the
uppermost portions of the aquifer.  Instead, an average value should be used.  The
average temperature of shallow groundwater in the United States is shown in Figure
6.3.

6.5.12  pH  TpH unitsi

The pH values of groundwater in the United States typically range between 6.0 and
8.5.  However, values as high as 11.0 for alkali-spring water and as low as 1.8 for
acid hot-spring water have been determined  (Mercer et al., 1982).  The pH can be
measured from groundwater samples in the field.  For some aquifers, data may be
available from the U.S. Geological Survey, the U.S. Environmental Protection Agency,
or from state and local agencies.

6.5.13  Organic Carbon Content  (Fraction)  [--1

The fractional organic carbon content can be estimated from the percent organic
matter by the following relationship:

         foc =  fom/172.4                                                         (6.18)

where

         foc   = fractional organic carbon content  [dimensionless]
         fom   = percent organic matter  [dimensionless]
         172.4 = conversion factor from percent organic matter content to
                 fractional organic carbon content

Information about the percent organic matter in soils is provided in Section 6.4.3.
Typically the value of the percent organic matter  (and hence, the fractional organic
carbon content)  is smaller for an aquifer than for near-surface soils.

6.5.14  Well Distance from Site  [ml ,  Angle off Center [degrees! , and Well
        Vertical Distance  [ml

A schematic of the receptor well location relative to the waste facility was
presented in Figure 6.1.  The location of the well is determined by specifying the
radial distance to the well, the angle between the plume centerline and the radial
location of the well measured counterclockwise and the depth of penetration of the
well.  The well screen depth is specified as the fraction  (i.e., a value between 0
and 1) of the total aquifer thickness and is measured downward from the water table.
The well is assumed to have a single opening at the depth specified.  The code uses
the input to calculate the cartesian coordinates of the well location as discussed in
Section 5.2.3.

For Subtitle D applications of the model, a conservative approach is required.  Thus,
the well is assumed to be located on the contaminant plume centerline  (i.e., the
angle off center is fixed at zero degrees) and the well vertical distance is also
fixed at zero (i.e.,  the contaminant concentration is predicted at the water table).
                                         103

-------
Figure 6.3
                                          104

-------
                                      SECTION 7
                                   EXAMPLE PROBLEMS
Three example problems are presented in this section.  These problems are designed to
demonstrate the application of MULTIMED to a variety of scenarios which might be
encountered while studying Subtitle D facilities.  Example 1 is a deterministic,
steady-state simulation of transport in the saturated zone.  The second example is
identical to Example 1, but includes flow and transport in the unsaturated zone.
This example is included in the deterministic tutorial for the preprocessor,  PREMED,
and can be accessed from the opening screen of the preprocessor by typing
<@DETER.LOG> (do not type the brackets).   Example 3 is similar to Example 2,  but it
is run in Monte-Carlo mode.  This example is the same as the input generated by the
Monte Carlo tutorial,  which is accessed from the preprocessor opening screen by
typing <@MONTE.LOG>.

Because new versions of the MULTIMED code may be released after the publication of
this document,  the results presented in this section may differ from the result
obtained from using the input generated by the tutorials.  Therefore, these examples
should not be viewed as validation data sets.  Input and output for model validation
are distributed with the code.

Note that the scenarios represented by these simulations are hypothetical, and are
not intended to resemble any actual sites.  The values used in these example problems
are not EPA-recommended values for use in MULTIMED.

7.1  EXAMPLE 1

7.1.1  The Hypothetical Scenario

A well which supplies drinking water to a small community is located 152 meters
directly downgradient from a waste disposal facility.  The members of the community
want to predict the effect of the waste disposal facility on the water quality in the
well.

The bottom of the waste disposal facility is located just above the water table.
Therefore, simulation of flow and transport in the unsaturated zone is unnecessary,
and only saturated transport is simulated.

One contaminant has been selected by the community for simulation, based on its
unusual persistence in the subsurface environment.  This contaminant is not
biodegradable,  and has an overall chemical decay coefficient which is so small it can
be assumed to be zero  (this is a conservative approach).   The normalized
                                         106

-------
distribution coefficient for the contaminant is also assumed to be zero, so the
chemical will not be removed from the groundwater by the process of adsorption.
For convenience in calculating the dilution attenuation factor  (DAF),  discussed in
Section 5.2.4,  the concentration of the contaminant at the bottom of the facility is
assumed to be 1.00 mg/1.  This source concentration is constant in time.  The area of
the waste disposal site is approximately 400 m2 and it  is  square in shape.   The
infiltration rate into the aquifer beneath the facility is .007 m/yr,  and the
recharge rate into the aquifer downgradient of the facility is slightly higher at
.0076 m/yr.  No temporal variability in these rates has been observed.

The aquifer is 78.6 meters thick and the hydraulic gradient within the aquifer is
constant at 0.0306.  The estimated longitudinal dispersivity in the aquifer is 160 m,
the transverse dispersivity is 15.2 m and the vertical dispersivity is 8 m.  The
fraction of organic carbon in the aquifer is .00315.  The pH of the groundwater in
the aquifer is typical of many groundwaters in the United States and has been
measured to be 6.20.  The average annual temperature in the aquifer is 14.4 °C.

The lack of temporal variability in this system indicates that a steady-state
simulation is appropriate.  Furthermore, the values of the parameters are known with
a high degree of certainty, so a deterministic simulation was selected.

7.1.2  Input

MULTIMED input for Example 1 is shown in Table 7-1.  It consists of the title for the
Example 1 simulation,  followed by several data groups.   The values assigned to
specific parameters are clearly labeled for all of the data groups except the General
data group.  The parameters in the General Data Group and the format of the entire
input sequence are discussed in Appendix A.
Since only the saturated transport module is used in this example, the General Data
Group is followed by three data groups: the Chemical, Source and Aquifer Specific
Variable Data.   In these data groups, the name of the input parameter and the units
for the parameter are in the left hand column.   The values listed under
"Distribution"  indicate whether the parameter is to be derived from other parameters
(-1 or -2)  or read from the input sequence  (0).  Since this is a deterministic
simulation, only the values listed in the "Mean" column will be used by the model
(the standard deviation, and the minimum and maximum limits are applicable only in a
Monte Carlo simulation).

All of the Chemical Specific Parameters used by MULTIMED are listed in the input
file.  However, not all of these parameters are used in the Example 1 simulation.  A
discussion of which parameters are required by the saturated zone transport module
can be found in Section 5.3.  To avoid obtaining values for unnecessary parameters
when developing an input sequence for MULTIMED, refer to Section 5.3,  which discusses
the parameters required for specific modules, and Section 6,  which discusses the
estimation and/or derivation of these parameters.

Values for some parameters may be listed as -999.  These parameters are undefined.
Files generated by the preprocessor list some of the parameters which are not used by
the code as -999.  PREMED will check that all of the necessary values for a
particular simulation have been defined before saving an input file.   If a value of -
999 appears in the input sequence for a parameter which is required by the code, this
parameter will be listed as "Undefined", and must be specified to complete the input
sequence for use in MULTIMED.  The specification of "Undefined" parameters is clearly
demonstrated in the PREMED tutorials.
                                         107

-------
TABLE 7-1.  INPUT SEQUENCE  FOR  EXAMPLE 1.
Example 1.
                                                                                              Test input sequence for MULTIMED.
GENERAL DATA

***  CHEMICAL NAME FORMAT(8OA1)
DEFAULT CHEMICAL

***    ISOURC
***OPTION   OPTAIR  RUN
    100     DETERMINISTIC
     ROUTE      NT        IYCHK    PALPH      APPTYP
MONTE    ISTEAD      IOPEN    IZCHK     LANDF   COMPLETE
  1    1    1    1     0     0     090.0    0    2    1
***   XST

END GENERAL

CHEMICAL SPECIFIC VARIABLE  DATA
ARRAY VALUES
***      CHEMICAL SPECIFIC  VARIABLES
*** VARIABLE NAME UNITS
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Solid phase decay coeff (1/yr)
Diss phase decay coeff (1/yr)
Overall chem dcy coeff (1/yr)
Acid cataly hydrol rte(l/M-yr)
Neutral hydrol rate cons (1/yr)
Base cataly hydrol rte(l/M-yr)
Reference temperature (C)
Normalized distrib coeff (ml/g)
Distribution coefficient
Biodegrad coef (sat zone) (1/yr)
Air diffusion coeff (cm2/s)
Ref temp for air diffusion (C)
Molecular weight (g/mole)
Mole fraction of solute
Solute vapor pressure (mm Hg)
Henry's law cons (atm-m^3/M)
Not in use
Not in use
Not in use
MEAN
-1
-1
-1
0
0
0
0
0
-2
0
0
0
0
0
0
0
0
0
0
DISTRIBUTION
STD DEV
0
0
0
0
0
0
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
00
00
00
00
00
00
25.0
0
0
0
0
0
-
-
-
-
1
1
1
.OOOE+
.219
.OOOE+
.OOOE+
.OOOE+
999.
999.
999.
999.
.00
.00
.00
00

00
00
00







PARAMETERS LIMITS
MIN MAX
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.645E-02
.OOOE+00
.OOOE+00
.100E-01
.230E-01
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
0 .
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.100E-08
.OOOE+00
.100E-09
.OOOE+00
.OOOE+00
.OOOE+00
0 .100E+11
0 .100E+
11
0 .100E+11
-999.
-999.
-999.
100 .
-999.





0 .100E+11
-999.
10 .0
100 .
-999.
1.00
100 .
1.00
1.00
1.00
1.00










END ARRAY
END CHEMICAL SPECIFIC VARIABLE  DATA

(continued)
                                                                     108

-------
TABLE 7-1.  INPUT SEQUENCE  FOR EXAMPLE 1  (concluded)
SOURCE SPECIFIC VARIABLE  DATA
ARRAY VALUES
***        SOURCE SPECIFIC  VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
 PARAMETERS
MEAN      STD DEV
                                                                                                        LIMITS
                                                                                                     MIN      MAX
1
2
3
4
5
6
7
8
9
Infiltration rate (m/yr)
Area of waste disp unit (m^2)
Duration of pulse (yr)
Spread of contaminant srce (m)
Recharge rate (m/yr)
Source decay constant (1/yr)
Init cone at landfill (mg/1)
Length scale of facility (m)
Width scale of facility (m)
0
0
0
-1
0
0
0
-1
-1
0

-
-
0
0

-
-
.700E-02
400 .
999.
999.
.760E-02
.OOOE+00
1.00
999.
999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0
0
0
0
0
0
0
0
0
.100E-09
.100E-01
.100E-08
.100E-08
.100E-09
.OOOE+00
.OOOE+00
.100E-08
.100E-08
0
-
-
0
0
-
-
0
0
.100E+11
999.
999.
.100E+11
.100E+11
999.
999.
.100E+11
.100E+11
END ARRAY
END SOURCE SPECIFIC VARIABLE  DATA

AQUIFER SPECIFIC VARIABLE  DATA
ARRAY VALUES
***       AQUIFER SPECIFIC VARIABLES
*** VARIABLE NAME UNITS
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Particle diameter (cm)
Aquifer porosity
Bulk density (g/cc)
Aquifer thickness (m)
Mixing zone depth (m)
Hydraulic conductivity (m/yr)
Hydraulic Gradient
Grndwater seep velocity (m/yr)
Retardation coefficient
Longitudinal dispersivity (m)
Transverse dispersivity (m)
Vertical dispersivity (m)
Temperature of aquifer (C)
pH
Organic carbon content (fract)
Receptor distance from site(m)
Angle off center (degree)
Well vert dist from water tabl
DISTRIBUTION PARAMETERS
MEAN STD DEV
0
-2
-2
0
-1
-2
0
-2
-1
0
0
0
0
0
0
0
0
0
0 .630E-03
-999.
-999.
78 .6
-999.
-999.
0 .306E-01
-999.
-999.
160 .
15.2
8 .00
14 .4
6 .20
0 .315E-02
152 .
0 .OOOE+00
0 .OOOE+00
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0
0
0
0
0
0
0
0

0
0
0
0
0
0

0
0
LIMITS
MIN MAX
.100E-08
.100E-08
.100E-01
.100E-08
.100E-08
.100E-06
.100E-07
.100E-09
1.00
.100E-02
.100E-02
.100E-02
.OOOE+00
.300
.100E-05
1.00
.OOOE+00
.OOOE+00
0

0
0
0
-
0
0
0
0
0



-


100 .
.990
5.00
.100EH


-06
.100E+06
.100EH
999.
.100EH
-09

-09
.100E+09
.100EH
-05
.100E+05
.100EH
100 .
14 .0
1.00
999.
360 .
1.00
-05






END ARRAY
END AQUIFER SPECIFIC VARIABLE  DATA
END ALL DATA
                                                                     109

-------
7.1.3  Output

The output for example 1 consists the main output file, the SAT.OUT file, and
files with a *.VAR extension, which are not shown.  For deterministic
simulations, the *.VAR files echo the values of the constant parameters and list
the values calculated by the code for the derived parameters.   Table 7-2
presents the main output file,  which consists of an echo of the input and the
predicted contaminant concentration at the well.  The SAT.OUT file, shown in
Table 7-3, lists the predicted contaminant concentration at the well.

7.2  EXAMPLE 2

7.2.1  The Hypothetical Scenario

The second example is identical to the first with one exception: the water table
is located at a depth of 6.1 meters below the bottom of the waste disposal
facility.  Therefore, unsaturated flow and transport must also be simulated.

In this example, the unsaturated zone consists of one homogeneous layer with the
following known values for material and transport properties.  The saturated
hydraulic conductivity is .017 cm/hr, the porosity is 0.43 and the bulk density
is 1.67 g/cm3.   The  percent  organic  matter is  0.026  and the  Brooks  and  Corey
exponent is 0.5.  The van Genuchten parameters, a and 3, which describe the
relationship between the pressure head and water saturation, are .009 and 1.23,
respectively.  The residual water content is .088 and the longitudinal
dispersivity is .4 m.

7.2.2  Input

The chemical, source, and aquifer specific parameters are the same as those
described in Example 1.  However, simulation of the unsaturated zone requires
additional data groups in the input file including soil moisture parameters and
unsaturated zone transport parameters.  The input for Example 2 is shown in Table
7-4 .

7.2.3  Output

The output for Example 2 is similar to that described for Example 1.  In addition
to the main output file, shown in Table 7-5, the SAT.OUT file, presented in Table
7-6,  and the *.VAR files, two additional files, VFLOW.OUT and VTRNSPT.OUT, are
created.  VFLOW.OUT contains output for the Unsaturated Zone Flow Module,
including the depth of each node and the Darcy velocity, water saturation, and
head at each node.   (Note that the number and location of nodes is determined by
the MULTIMED code.)   VTRNSPT.OUT lists the steady-state concentration at the
water table.
                                       110

-------
            TABLE 7-2.   OUTPUT FILE FOR EXAMPLE 1.
                        4444444444444444444444444444444


                        U. S.    ENVIRONMENTAL   PROTECTION   AGENCY

                                         EXPOSURE   ASSESSMENT

                                            MULTIMEDIA   MODEL

                                               VERSION 3.3,  DECEMBER 1988

                                   Developed by Phillip Mineart and Atul Salhotra of
                                   Woodward-Clyde Consultants,  Oakland, California
                                                  In cooperation with:
                                       Hydrogeologic,  Inc.,  Herndon,  Virginia,
                                           Geotrans,  Inc.,  Herndon,  Virginia,
                                                          and
                                   Aqua Terra Consultants,  Mountain View, California
Run options
Subtitle D landfill application.
Chemical simulated is DEFAULT CHEMICAL
Option Chosen
Run was
Infiltration input by user
Run was steady-state
Rej ect runs if Y coordinate outside plume
Rej ect runs if Z coordinate outside plume
Gaussian source used in saturated  zone model
Saturated zone model
DETERMIN
                                                                                                                             (continued)
                                                                           111

-------
TABLE 7-2.  OUTPUT  FILE  FOR EXAMPLE 1.
                                                      CHEMICAL SPECIFIC VARIABLES
VARIABLE NAME

Solid phase decay coefficient
Dissolved phase decay coefficient
Overall chemical decay coefficient
Acid catalyzed hydrolysis rate
Neutral hydrolysis rate constant
Base catalyzed hydrolysis rate
Reference temperature
Normalized distribution coefficient
Distribution coefficient
Biodegradation coefficient (sat. zone)
Air diffusion coefficient
UNITS

1/yr
1/yr
1/yr
1/M-yr
1/yr
1/M-yr
C
ml/g

1/yr
cm2/s
Reference temperature for air diffusion C
Molecular weight
Mole fraction of solute
Vapor pressure of solute
Henry "s law constant
RFD value for drinking water
ADIF value for fish consumption
CCC for aquatic organisms

VARIABLE NAME
Infiltration rate
Area of waste disposal unit
Duration of pulse
Spread of contaminant source
Recharge rate
Source decay constant
Initial concentration at landfill
Length scale of facility
Width scale of facility
Near field dilution
g/M
--
mm Hg
atm-mA3/M
mg-kg/day
mg-kg/day
mg-kg/day
SOURCE
UNITS
m/yr
m~2
yr
m
m/yr
1/yr
mg/1
m
m

DISTRIBUTION

DERIVED
DERIVED
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
SPECIFIC VARIABLES
DISTRIBUTION
CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
DERIVED
DERIVED
CONSTANT
PARAMETERS
MEAN
O.OOOE+
O.OOOE+
O.OOOE+
O.OOOE+
O.OOOE+
O.OOOE+
25.0
O.OOOE+
0.219
O.OOOE+
O.OOOE+
O.OOOE+
-999.
-999.
-999.
-999.
1.00
1.00
1.00

STD DEV
00
00
00
00
00
00

00

00
00
00








0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.645E-
.OOOE+
.OOOE+
.100E-
.230E-
.OOOE+
.OOOE+
.OOOE+
.OOOE+

00
00
00
00
00
00
00
00
00
00
02
00
00
01
01
00
00
00
00

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

PARAMETERS
MEAN STD DEV
0.700E-
400.
-999.
-999.
0.760E-
O.OOOE+
1.00
-999.
-999.
O.OOOE+
02



02
00



00
-
-
-
-
-
-
-
-
-
0
999.
999.
999.
999.
999.
999.
999.
999.
999.
.OOOE+









00
0
0
0
0
0
0
0
0
0
0
LIMITS
MIN
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.100E-08
.OOOE+00
.100E-09
.OOOE+00
.OOOE+00
.OOOE+00


0
0
0
-
-
-

-
0
-


-







LIMITS
MIN
.100E-09
. 100E-01
.100E-08
.100E-08
.100E-09
.OOOE+00
.OOOE+00
.100E-08
.100E-08
.OOOE+00
0
-
-
0
0
-
-
0
0
0
MAX
.100E+11
.100E+11
.100E+11
999.
999.
999.
100.
999.
.100E+11
999.
10.0
100.
999.
1.00
100.
1.00
1.00
1.00
1.00

MAX
.100E+11
999.
999.
.100E+11
.100E+11
999.
999.
.100E+11
.100E+11
.OOOE+00
                                                                                                                                (continued)
                                                                             112

-------
TABLE 7-2.  OUTPUT FILE FOR EXAMPLE  1   (concluded).
                                                        AQUIFER SPECIFIC VARIABLES
VARIABLE NAME
Particle diameter
Aquifer porosity
Bulk density
Aquifer thickness
Source thickness (mixing zone depth)
Conductivity (hydraulic)
Gradient (hydraulic)
Groundwater seepage velocity
Retardation coefficient
Longitudinal dispersivity
Transverse dispersivity
Vertical dispersivity
Temperature of aquifer
pH
Organic carbon content (fraction)
Well distance from site
Angle off center
Well vertical distance
UNITS
cm
--
g/cc
m
m
m/yr

m/yr
--
m
m
m
C
--

m
degree
m
DISTRIBUTION
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
PARAMETERS
MEAN STD DEV
0
-
-

-
-
0
-
-





0

0
0
.630E-03
999.
999.
78.6
999.
999.
.306E-01
999.
999.
160.
15.2
8.00
14.4
6.20
.315E-02
152.
.OOOE+00
.OOOE+00
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0.
0.
0.
0.
0.
0.
0.
0.
1
0.
0.
0.
0.
0.
0.
1
0.
0.
LIMITS
MIN
100E-
100E-
100E-
100E-
100E-
100E-
100E-
100E-
.00
100E-
100E-
100E-
OOOE+
300
100E-
.00
OOOE+
OOOE+
08
08
01
08
08
06
07
09

02
02
02
00

05

00
00

0

0
0
0
-
0
0
0
0
0



-


MAX
100.
.990
5.00
.100E+
.100E+
.100E+
999.
.100E+
.100E+
.100E+
.100E+
.100E+
100.
14.0
1.00
999.
360.
1.00




06
06
09

09
09
05
05
05






     CONCENTRATION AFTER SATURATED ZONE  MODEL 0.5736E-03
                                                                              113

-------
TABLE 7-3.   SAT.OUT FILE FOR EXAMPLE  1.
44
1

                     STEADY STATE SATURATED ZONE TRANSPORT RESULTS
  AT 0.1000E+04  YEARS,  CONCENTRATION  IS  0.5736E-03
                                                                              114

-------
TABLE 7-4.   INPUT SEQUENCE FOR  EXAMPLE 2.
444444444444444444444444444444444444444
Test input  sequence for MULTIMED.
Example 2.
GENERAL DATA

***  CHEMICAL NAME FORMAT(80A1)
DEFAULT CHEMICAL

***    ISOURC
***OPTION    OPTAIR  RUN
    200      DETERMINISTIC
     ROUTE       NT
MONTE     I STEAD
  1111
     IYCHK    PALPH      APPTYP
IOPEN     IZCHK      LANDF   COMPLETE
  000  90.0    021
***   XST

END GENERAL

CHEMICAL SPECIFIC VARIABLE DATA
ARRAY VALUES
***      CHEMICAL SPECIFIC VARIABLES
* * *
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
END
VARIABLE NAME UNITS
Solid phase decay coeff (1/yr)
Diss phase decay coeff (1/yr)
Overall chem dcy coeff (1/yr)
Acid cataly hydrol rte(l/M-yr)
Neutral hydrol rate cons (1/yr)
Base cataly hydrol rte(l/M-yr)
Reference temperature (C)
Normalized distrib coeff (ml/g)
Distribution coefficient
Biodegrad coef (sat zone) (1/yr)
Air diffusion coeff (cm2/s)
Ref temp for air diffusion (C)
Molecular weight (g/mole)
Mole fraction of solute
Solute vapor pressure (mm Hg)
Henry^s law cons (atm-mA3/M)
Not in use
Not in use
Not in use
ARRAY
DISTRIBUTION
-1
-1
-1
0
0
0
0
0
-2
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
-
-
-
-




PARAMETERS
MEAN STD
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
25.0
.OOOE+
.219
.OOOE+
.OOOE+
.OOOE+
999.
999.
999.
999.
1.00
1.00
1.00

00
00
00
00
00
00

00

00
00
00








0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.645E
.OOOE
.OOOE
.100E
.230E
.OOOE
.OOOE
.OOOE
.OOOE

DEV
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
-02
+ 00
+ 00
-01
-01
+ 00
+ 00
+ 00
+ 00

LIMITS
MIN MAX
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.100E-08
.OOOE+00
.100E-09
.OOOE+00
.OOOE+00
.OOOE+00

0.100E+11
0.100E+11
0.100E+11
-999.
-999.
-999.
100.
-999.
0.100E+11
-999.
10.0
100.
-999.
1.00
100.
1.00
1.00
1.00
1.00

END CHEMICAL  SPECIFIC VARIABLE DATA
                                                                                                                              (continued)
                                                                               115

-------
TABLE 7-4.   INPUT  SEQUENCE FOR EXAMPLE 2.
4444444444444444444444444444444444'
SOURCE SPECIFIC  VARIABLE DATA
ARRAY VALUES
***        SOURCE  SPECIFIC VARIABLES
*
*









* *
* *
1
2
3
4
5
6
7
8
9
END
VARIABLE NAME UNITS
Infiltration rate (m/yr)
Area of waste disp unit (mA2)
Duration of pulse (yr)
Spread of contaminant srce (m)
Recharge rate (m/yr)
Source decay constant (1/yr)
Init cone at landfill (mg/1)
Length scale of facility (m)
Width scale of facility (m)
ARRAY
DISTRIBUTION
0
0
0
-1
0
0
0
-1
-1

PARAMETERS
MEAN STD
0.700E-02
400.
-999.
-999.
0.760E-02
O.OOOE+00
1.00
-999.
-999.

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

DEV
0
0
0
0
0
0
0
0
0

MIN
.100E
.100E
.100E
.100E
.100E
.OOOE
.OOOE
.100E
.100E

LIMITS
MAX
-09
-01
-08
-08
-09
+ 00
+ 00
-08
-08

0
-
-
0
0
-
-
0
0

.100E+11
999.
999.
.100E+11
.100E+11
999.
999.
.100E+11
.100E+11

END SOURCE SPECIFIC VARIABLE DATA
VFL   UNSATURATED  FLOW MODEL PARAMETERS
CONTROL PARAMETERS
***    DUMMY      NMAT      KPROP     DUMMY     NVFLAY
         71211

END CONTROL PARAMETERS
MATERIAL NUMBER  FOR EACH LAYER
  6.10              1
END MATERIAL  PARAMETERS
SATURATED MATERIAL  PROPERTY PARAMETERS
ARRAY VALUES
***   SATURATED  MATERIAL   VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                  DISTRIBUTION
                                                                                  PARAMETERS
                                                                                 MEAN      STD DEV
                           LIMITS
                        MIN      MAX
 1 Sat hydraulic  conduct (cm/hr)
 2 Unsaturated  zone porosity
 3 Air entry pressure head (m)
 4 Depth of the unsat zone (m)
END ARRAY
0.170E-01 -999.
0.430     -999.
O.OOOE+00 -999.
 6.10     -999.
0.100E-10 0.100E+05
0.100E-08 0.990
O.OOOE+00 -999.
0.100E-08 -999.
END MATERIAL   1
END
                                                                                                                                (continued)
                                                                              116

-------
TABLE 7-4.  INPUT SEQUENCE FOR EXAMPLE  2.
SOIL MOISTURE PARAMETERS
***   FUNCTIONAL COEFFICIENTS
ARRAY VALUES
***   FUNCTIONAL COEFFICIE VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
                                                                                PARAMETERS
                                                                               MEAN      STD DEV
                                                                   LIMITS
                                                                MIN      MAX
 1 Residual water content
 2 Brooks and Corey exponent, EN
 3 ALFA van Genuchten coefficient
 4 BETA Van Genuchten coefficient
END ARRAY
                                        0.880E-01  -999.
                                        0.500      -999.
                                        0.900E-02  -999.
                                         1.23      -999.
                                                 0.100E-08   1.00
                                                 O.OOOE+00   10.0
                                                 O.OOOE+00   1.00
                                                  1.00       5.00
END MATERIAL  1
END
END UNSATURATED FLOW
VTP    UNSATURATED TRANSPORT MODEL
CONTROL PARAMETERS
***   NLAY     DUMMY      IADU
         1        20         1
***  WTFUN
     1.200
ISOL
   1
 N
18
NTEL
   3
NGPTS
  104
NIT
  2
DUMMY
    1
DUMMY
    1
END CONTROL PARAMETERS
TRANSPORT PARAMETER
ARRAY VALUES
***   UNSATURATED TRANSPOR VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
                                                                                PARAMETERS
                                                                               MEAN      STD DEV
                                                                   LIMITS
                                                                MIN      MAX
 1 Thickness of layer  (m)
 2 Longit disper of layer  (m)
 3 Percent organic matter
 4 Bulk dens of soil layer  (g/cc)
 5 Biological decay coeff  (1/yr)
END ARRAY
                                 0       6.10      -999.      0.100E-08  -999.
                                 0      0.400      -999.      O.OOOE+00  0.100E+05
                                 0      0.260E-01  -999.      O.OOOE+00   100.
                                 0       1.67      -999.      0.100E-01   5.00
                                 0      O.OOOE+00  -999.      O.OOOE+00  -999.
END LAYER  1
END UNSATURATED TRANSPORT PARAMETERS
END TRANSPORT MODEL
                                                                                                                                 (continued)
                                                                            117

-------
TABLE 7-4.   INPUT SEQUENCE FOR EXAMPLE 2   (concluded).
AQUIFER SPECIFIC  VARIABLE DATA
ARRAY VALUES
***       AQUIFER SPECIFIC VARIABLES
* * *
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
END
VARIABLE NAME UNITS
Particle diameter (cm)
Aquifer porosity
Bulk density (g/cc)
Aquifer thickness (m)
Mixing zone depth (m)
Hydraulic conductivity (m/yr)
Hydraulic Gradient
Grndwater seep velocity (m/yr)
Retardation coefficient
Longitudinal dispersivity (m)
Transverse dispersivity (m)
Vertical dispersivity (m)
Temperature of aquifer (C)
pH
Organic carbon content (fract)
Receptor distance from site(m)
Angle off center (degree)
Well vert dist from water tabl
ARRAY
DISTRIBUTION PARAMETERS
MEAN STD DEV
0
-2
-2
0
-1
-2
0
-2
-1
0
0
0
0
0
0
0
0
0

0.630E-03
-999.
-999.
78.6
-999.
-999.
0.306E-01
-999.
-999.
160.
15.2
8.00
14.4
6.20
0.315E-02
152.
O.OOOE+00
O.OOOE+00

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

0.
0.
0.
0.
0.
0.
0.
0.
1
0.
0.
0.
0.
0.
0.
1
0.
0.

LIMITS
MIN MAX
100E-
100E-
100E-
100E-
100E-
100E-
100E-
100E-
.00
100E-
100E-
100E-
OOOE+
300
100E-
.00
OOOE+
OOOE+

08
08
01
08
08
06
07
09

02
02
02
00

05

00
00


0

0
0
0
-
0
0
0
0
0



-



100.
.990
5.00
.100E+
.100E+
.100E+
999.
.100E+
.100E+
.100E+
.100E+
.100E+
100.
14.0
1.00
999.
360.
1.00




06
06
09

09
09
05
05
05







END AQUIFER  SPECIFIC VARIABLE DATA
END ALL DATA
                                                                              118

-------
TABLE 7-5.  MAIN OUTPUT FILE FOR EXAMPLE 2.
                         U. S.    ENVIRONMENTAL   PROTECTION   AGENCY

                                         EXPOSURE   ASSESSMENT

                                            MULTIMEDIA   MODEL

                                               VERSION 3.3, DECEMBER 1988

                                   Developed by Phillip Mineart and Atul Salhotra of
                                    Woodward-Clyde Consultants, Oakland, California
                                                  In cooperation with:
                                        Hydrogeologic, Inc.,  Herndon, Virginia,
                                           Geotrans, Inc.,  Herndon, Virginia,
                                                          and
                                   Aqua Terra Consultants,  Mountain View, California
 Run options
 Subtitle D landfill application.
 Chemical simulated is DEFAULT CHEMICAL
 Option Chosen
 Run was
 Infiltration input by user
 Run was steady-state
 Rej ect runs if Y coordinate outside plume
 Rej ect runs if Z coordinate outside plume
 Gaussian source used in saturated zone model
Saturated and unsaturated zone models
DETERMIN
 UNSATURATED ZONE FLOW MODEL PARAMETERS
 (input parameter description and value)
 NP     - Total number of nodal points
 NMAT   - Number of different porous materials
 KPROP  - Van Genuchten or Brooks and Corey
 IMSHGN - Spatial discretization option
        1
                 240
                   1
                   2
                   1
 OPTIONS CHOSEN

 Brooks and Corey functional coefficients
 User defined coordinate system
                                                                                                                          (continued)
                                                                           119

-------
TABLE 7-5.  MAIN OUTPUT FILE FOR EXAMPLE 2.
4444444444444444444444
 Layer information

 LAYER NO.    LAYER THICKNESS     MATERIAL PROPERTY

     1                   6.10              1
                                                      DATA FOR MATERIAL  1

                                                  VADOSE ZONE MATERIAL VARIABLES
VARIABLE NAME

Saturated hydraulic conductivity
Unsaturated zone porosity
Air entry pressure head
Depth of the unsaturated zone
UNITS

cm/hr
--
m
m
DISTRIBUTION

CONSTANT
CONSTANT
CONSTANT
CONSTANT
PARAMETERS

0
0
0

MEAN
.170E-01
.430
.OOOE+00
6.10
STD DEV
-999.
-999.
-999.
-999.

0
0
0
0
LIMITS
MIN
. 100E-
. 100E-
.OOOE+
. 100E-

10
08
00
08

0
0
-
-
MAX
.100E+
.990
999.
999.

05



 UNSATURATED ZONE TRANSPORT MODEL PARAMETERS

 NLAY   - Number of different layers used                 1
 NTSTPS - Number of time values concentration calc       20
 DUMMY  - Not presently used                              1
 ISOL   - Type of scheme used in unsaturated zone         1
 N      - Stehfest terms or number of increments         18
 NTEL   - Points in Lagrangian interpolation              3
 NGPTS  - Number of Gauss points                        104
 NIT    - Convolution integral segments                   2
 IBOUND - Type of boundary condition                      1
 ITSGEN - Time values generated or input                  1
 TMAX   - Max simulation time             --             0.0
 WTFUN  - Weighting factor                --             1.2
 OPTIONS CHOSEN

 Stehfest numerical inversion algorithm
 Nondecaying continuous source
 Computer generated times for computing concentrations
                                                                                                                           (continued)
                                                                            120

-------
TABLE 7-5.  MAIN OUTPUT  FILE FOR EXAMPLE 2.
                                                       DATA  FOR  LAYER   1




                                                       VADOSE  TRANSPORT VARIABLES
VARIABLE NAME

Thickness of layer
Longitudinal dispersivity of layer
Percent organic matter
Bulk density of soil for layer
Biological decay coefficient

VARIABLE NAME
Solid phase decay coefficient
Dissolved phase decay coefficient
Overall chemical decay coefficient
Acid catalyzed hydrolysis rate
Neutral hydrolysis rate constant
Base catalyzed hydrolysis rate
Reference temperature
Normalized distribution coefficient
Distribution coefficient
Biodegradation coefficient (sat. zone)
Air diffusion coefficient
UNITS

m
m
--
g/cc
1/yr
CHEMICAL
UNITS
i/yr
1/yr
1/yr
1/M-yr
1/yr
1/M-yr
C
ml/g

1/yr
cm2/s
Reference temperature for air diffusion C
Molecular weight
Mole fraction of solute
Vapor pressure of solute
Henry "s law constant
RFD value for drinking water
ADIF value for fish consumption
CCC for aquatic organisms
g/M
--
mm Hg
atm-mA3/M
mg-kg/day
mg-kg/day
mg-kg/day
DISTRIBUTION

CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
SPECIFIC VARIABLES
DISTRIBUTION
DERIVED
DERIVED
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
PARAMETERS


0
0

0

MEAN
6.10
.400
.260E-
1.67
.OOOE+




01

00


-
-
-
-
-

STD DEV
999.
999.
999.
999.
999.


0
0
0
0
0

PARAMETERS
MEAN STD DEV
0
0
0
0
0
0

0
0
0
0
0
-
-
-
-



.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
25.0
.OOOE+
.219
.OOOE+
.OOOE+
.OOOE+
999.
999.
999.
999.
1.00
1.00
1.00
00
00
00
00
00
00

00

00
00
00







0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.645E-02
.OOOE+00
.OOOE+00
.100E-01
.230E-01
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
MIN
.100E
.OOOE
.OOOE
.100E
.OOOE

MIN
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.100E
.OOOE
.100E
.OOOE
.OOOE
.OOOE
LIMITS

-08 -
+ 00 0
+ 00
-01
+ 00 -

LIMITS
+ 00 0
+ 00 0
+ 00 0
+ 00 -
+ 00 -
+ 00 -
+ 00
+ 00 -
+ 00 0
+ 00 -
+ 00
+ 00
+ 00 -
-08
+ 00
-09
+ 00
+ 00
+ 00

MAX
999.
.100E+05
100.
5.00
999.

MAX
.100E+11
.100E+11
.100E+11
999.
999.
999.
100.
999.
.100E+11
999.
10.0
100.
999.
1.00
100.
1.00
1.00
1.00
1.00
                                                                                                                             (continued)
                                                                             121

-------
TABLE 7-5.  MAIN OUTPUT FILE FOR EXAMPLE 2  (concluded).
                                                       SOURCE SPECIFIC VARIABLES
VARIABLE NAME
Infiltration rate
Area of waste disposal unit
Duration of pulse
Spread of contaminant source
Recharge rate
Source decay constant
Initial concentration at landfill
Length scale of facility
Width scale of facility
Near field dilution

VARIABLE NAME
Particle diameter
Aquifer porosity
Bulk density
Aquifer thickness
Source thickness (mixing zone depth)
Conductivity (hydraulic)
Gradient (hydraulic)
Groundwater seepage velocity
Retardation coefficient
Longitudinal dispersivity
Transverse dispersivity
Vertical dispersivity
Temperature of aquifer
pH
Organic carbon content (fraction)
Well distance from site
Angle off center
Well vertical distance
UNITS
m/yr
m~2
yr
m
m/yr
1/yr
mg/1
m
m

AQUIFER
UNITS
cm
--
g/cc
m
m
m/yr

m/yr
--
m
m
m
C
--

m
degree
m
DISTRIBUTION
CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
DERIVED
DERIVED
CONSTANT
SPECIFIC VARIABLES
DISTRIBUTION
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
PARAMETERS
MEAN STD DEV
0

-
-
0
0

-
-
0

.700E-02
400.
999.
999.
.760E-02
.OOOE+00
1.00
999.
999.
.OOOE+00

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0. OOOE+00

0.
0.
0.
0.
0.
0.
0.
0.
0.
0.

PARAMETERS
MEAN STD DEV
0
-
-

-
-
0
-
-





0

0
0
.630E-03
999.
999.
78.6
999.
999.
.306E-01
999.
999.
160.
15.2
8.00
14.4
6.20
.315E-02
152.
.OOOE+00
.OOOE+00
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0.
0.
0.
0.
0.
0.
0.
0.
1
0.
0.
0.
0.
0.
0.
1
0.
0.
MIN
100E
100E
100E
100E
100E
OOOE
OOOE
100E
100E
OOOE

MIN
100E
100E
100E
100E
100E
100E
100E
100E
.00
100E
100E
100E
OOOE
300
100E
.00
OOOE
OOOE
LIMITS
-09
-01
-08
-08
-09
+ 00
+ 00
-08
-08
+ 00

0
-
-
0
0
-
-
0
0
0

LIMITS
-08
-08
-01
-08
-08
-06
-07
-09

-02
-02
-02
+ 00

-05

+ 00
+ 00

0

0
0
0
-
0
0
0
0
0



-


MAX

.100E+11
999.
999.


.100E+11
.100E+11
999.
999.


.100E+11
.100E+11
.OOOE

MAX
100.
.990
5.00
.100E
.100E
.100E
999.
.100E
.100E
.100E
.100E
.100E
100.
14.0
1.00
999.
360.
1.00
+ 00





+ 06
+ 06
+ 09

+ 09
+ 09
+ 05
+ 05
+ 05






     CONCENTRATION AFTER SATURATED ZONE MODEL 0.5736E-03
                                                                           122

-------
TABLE 7-6.   SAT.OUT FILE FOR EXAMPLE  2.
44
1

                     STEADY STATE SATURATED ZONE TRANSPORT RESULTS
  AT 0.1000E+04  YEARS,  CONCENTRATION  IS  0.5736E-03
                                                                              123

-------
7.3  EXAMPLE 3

7.3.1  The Hypothetical Scenario

The third example is similar to Example 2.  The difference  is that  Example  3  is
run in Monte-Carlo mode instead of in a deterministic  framework.  In  this
example, spatial variability is observed  in the measured values  for two
parameters, which introduces uncertainty  into the model.  Therefore,  it  is
necessary to utilize the Monte Carlo option in MULTIMED.

In Example 3, all but three of the parameter values are constant or derived and
are identical to those in Example 2.  The three parameters  have  some  uncertainty
associated with their values.  Thus, they are described in  terms of probability
density functions which represent the uncertainty in the parameter  value.   The
theory behind the Monte Carlo analysis technique, and  the probability density
distributions included in MULTIMED, are discussed in Section 9 of Salhotra  et al.
(1990) .

The three uncertain parameters in Example 3 are the unsaturated  zone  hydraulic
conductivity  (cm/hr),  the unsaturated zone porosity, and the aquifer  pH.  In  this
example, the probability density distribution is lognormal  for the  hydraulic
conductivity, normal for the unsaturated  zone porosity, and uniform for  the
aquifer pH.  The normal and lognormal distributions both require specification of
a mean,  standard deviation, and minimum and maximum limits.  The uniform
distribution requires only the minimum and maximum limits of values.   Values  for
these parameters are shown in Table 7-7.

7.3.2  Input

The input sequence for Example 3 is shown in Table 7-8.  It is identical to the
input file for Example 2 except for changes in the General  Data  Group related to
running the model in a Monte Carlo framework, and differences in the  input  for
the three parameters which have been assigned Monte Carlo distributions.
TABLE 7-7.  MONTE CARLO DISTRIBUTION VALUES IN EXAMPLE 3
4444444444444444444444444444444444444444444444444444444444444444444
                                                         Standard       Limits
Parameter                  Distribution       Mean       Deviation   Min.   Max.

Saturated hydraulic
conductivity  (cm/hr)
for the unsaturated zone    Lognormal         .017        .020         .001   .250

Unsaturated zone
porosity                   Normal             .330        .100         .200   .450

Aquifer pH                 Uniform           NA          NA          5.80   6.90
                                            124

-------
TABLE 7-8.  INPUT SEQUENCE  FOR  EXAMPLE 3.
Example 3 input
Subtitle D application
GENERAL DATA

***  CHEMICAL NAME FORMAT(80A1)
DEFAULT CHEMICAL

***    ISOURC
***OPTION   OPTAIR  RUN
    200     MONTE
     ROUTE      NT
MONTE    I STEAD
500    111
     IYCHK   PALPH      APPTYP
IOPEN     IZCHK     LANDF   COMPLETE
  100 90.0    021
***   XST

END GENERAL

CHEMICAL SPECIFIC VARIABLE  DATA
ARRAY VALUES
***      CHEMICAL SPECIFIC  VARIABLES
* * *
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
END
VARIABLE NAME UNITS
Solid phase decay coeff (1/yr)
Diss phase decay coeff (1/yr)
Overall chem dcy coeff (1/yr)
Acid cataly hydrol rte(l/M-yr)
Neutral hydrol rate cons (1/yr)
Base cataly hydrol rte(l/M-yr)
Reference temperature (C)
Normalized distrib coeff (ml/g)
Distribution coefficient
Biodegrad coef (sat zone) (1/yr)
Air diffusion coeff (cm2/s)
Ref temp for air diffusion (C)
Molecular weight (g/mole)
Mole fraction of solute
Solute vapor pressure (mm Hg)
Henry^s law cons (atm-mA3/M)
Not in use
Not in use
Not in use
ARRAY
DISTRIBUTION
-1
-1
-1
0
0
0
0
0
-2
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0


0
0
0
0
-
-
-
-




PARAMETERS
MEAN STD
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
.OOOE+
25.0
140.
.219
.OOOE+
.OOOE+
.OOOE+
999.
999.
999.
999.
1.00
1.00
1.00

00
00
00
00
00
00



00
00
00








0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.OOOE
.645E
.OOOE
.OOOE
.100E
.230E
.OOOE
.OOOE
.OOOE
.OOOE

DEV
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
-02
+ 00
+ 00
-01
-01
+ 00
+ 00
+ 00
+ 00

LIMITS
MIN MAX
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.100E-08
.OOOE+00
.100E-09
.OOOE+00
.OOOE+00
.OOOE+00

0.100E+11
0.100E+11
0.100E+11
-999.
-999.
-999.
100.
-999.
0.100E+11
-999.
10.0
100.
-999.
1.00
100.
1.00
1.00
1.00
1.00

END CHEMICAL SPECIFIC VARIABLE  DATA
                                                                                                                                    (continued)
                                                                             125

-------
TABLE 7-8.  INPUT SEQUENCE  FOR  EXAMPLE  3.
SOURCE SPECIFIC VARIABLE DATA
ARRAY VALUES
***        SOURCE SPECIFIC VARIABLES
*
*









* *
* *
1
2
3
4
5
6
7
8
9
END
VARIABLE NAME UNITS
Infiltration rate (m/yr)
Area of waste disp unit (mA2)
Duration of pulse (yr)
Spread of contaminant srce (m)
Recharge rate (m/yr)
Source decay constant (1/yr)
Init cone at landfill (mg/1)
Length scale of facility (m)
Width scale of facility (m)
ARRAY
DISTRIBUTION
0
0
0
-1
0
0
0
-1
-1

PARAMETERS
MEAN STD
0.700E-02
400.
-999.
-999.
0.160E-01
O.OOOE+00
1.00
-999.
-999.

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

DEV
0
0
0
0
0
0
0
0
0

MIN
.100E
.100E
.100E
.100E
.100E
.OOOE
.OOOE
.100E
.100E

LIMITS
MAX
-09
-01
-08
-08
-09
+ 00
+ 00
-08
-08

0
-
-
0
0
-
-
0
0

.100E+11
999.
999.
.100E+11
.100E+11
999.
999.
.100E+11
.100E+11

END SOURCE SPECIFIC VARIABLE DATA
VFL   UNSATURATED FLOW MODEL  PARAMETERS
CONTROL PARAMETERS
***    DUMMY     NMAT       KPROP      DUMMY    NVFLAY
         71111
END CONTROL PARAMETERS
SATURATED MATERIAL PROPERTY  PARAMETERS
ARRAY VALUES
***   SATURATED MATERIAL   VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
                                                                                PARAMETERS
                                                                               MEAN      STD DEV
                                  LIMITS
                              MIN     MAX
 1 Sat hydraulic conduct  (cm/hr)
 2 Unsaturated zone porosity
 3 Air entry pressure head  (m)
 4 Depth of the unsat zone  (m)
END ARRAY
2      0.170E-01 0.200E-01 0.100E-03  0.250
1      0.330     0.100     0.200      0.450
0      O.OOOE+00 -999.     O.OOOE+00  -999.
0       6.10     -999.     0.100E-08  -999.
END MATERIAL  1
END
                                                                                                                                   (continued)
                                                                            126

-------
TABLE 7-8.  INPUT SEQUENCE FOR EXAMPLE  3.
SOIL MOISTURE PARAMETERS
***   FUNCTIONAL COEFFICIENTS
ARRAY VALUES
***   FUNCTIONAL COEFFICIE VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
                                                                                PARAMETERS
                                                                               MEAN      STD DEV
                                                                   LIMITS
                                                                MIN     MAX
 1 Residual water content
 2 Brooks and Corey exponent, EN
 3 ALFA van Genuchten coefficient
 4 BETA Van Genuchten coefficient
END ARRAY
                                        0.880E-01  -999.
                                        0.500      -999.
                                        0.900E-02  -999.
                                         1.23      -999.
                                                0.100E-08   1.00
                                                O.OOOE+00   10.0
                                                O.OOOE+00   1.00
                                                 1.00       5.00
END MATERIAL  1
END
END UNSATURATED FLOW
VTP    UNSATURATED TRANSPORT MODEL
CONTROL PARAMETERS
***   NLAY     DUMMY      IADU
         1        20         1
***  WTFUN
     1.200
ISOL
   1
 N
18
NTEL
   3
NGPTS
  104
NIT
  2
DUMMY
    1
DUMMY
    1
END CONTROL PARAMETERS
TRANSPORT PARAMETER
ARRAY VALUES
***   UNSATURATED TRANSPOR VARIABLES
               VARIABLE NAME
                                             UNITS
                                                                 DISTRIBUTION
                                                                                PARAMETERS
                                                                               MEAN      STD DEV
                                                                   LIMITS
                                                                MIN     MAX
 1 Thickness of layer  (m)
 2 Longit disper of layer  (m)
 3 Percent organic matter
 4 Bulk dens of soil layer  (g/cc)
 5 Biological decay coeff  (1/yr)
END ARRAY
                                 0       6.10      -999.      0.100E-08  -999.
                                 0      0.400      -999.      O.OOOE+00  0.100E+05
                                 0      0.260E-01  -999.      O.OOOE+00   100.
                                 0       1.45      -999.      0.100E-01   5.00
                                 0      O.OOOE+00  -999.      O.OOOE+00  -999.
END LAYER  1
END UNSATURATED TRANSPORT PARAMETERS
END TRANSPORT MODEL
                                                                                                                                   (continued)
                                                                            127

-------
TABLE 7-8.  INPUT SEQUENCE  FOR EXAMPLE 3  (concluded).
AQUIFER SPECIFIC VARIABLE  DATA
ARRAY VALUES
***       AQUIFER SPECIFIC VARIABLES
* * *
* * *
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
END
VARIABLE NAME UNITS
Particle diameter (cm)
Aquifer porosity
Bulk density (g/cc)
Aquifer thickness (m)
Mixing zone depth (m)
Hydraulic conductivity (m/yr)
Hydraulic Gradient
Grndwater seep velocity (m/yr)
Retardation coefficient
Longitudinal dispersivity (m)
Transverse dispersivity (m)
Vertical dispersivity (m)
Temperature of aquifer (C)
pH
Organic carbon content (fract)
Receptor distance from site(m)
Angle off center (degree)
Well vert dist from water tabl
ARRAY
DISTRIBUTION PARAMETERS
MEAN STD DEV
0
-2
-2
0
-1
-2
0
-2
-1
1
0
0
0
4
0
0
0
0

0.630E-03
-999.
-999.
78.6
-999.
-999.
0.306E-01
-999.
-999.
160.
15.2
8.00
14.4
-999.
0.315E-02
152.
O.OOOE+00
O.OOOE+00

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
15.0
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

0
0
0
0
0
0
0
0


0
0
0

0

0
0

LIMITS
MIN MAX
.100E-
.100E-
.100E-
.100E-
.100E-
.100E-
.100E-
.100E-
1.00
50.0
.100E-
.100E-
.OOOE+
5.80
.100E-
1.00
.OOOE+
.OOOE+

08
08
01
08
08
06
07
09


02
02
00

05

00
00


0

0
0
0
-
0
0

0
0



-



100.
.990
5.00
.100E+
.100E+
.100E+
999.
.100E+
.100E+
200.
.100E+
.100E+
100.
6.90
1.00
999.
360.
1.00




06
06
09

09
09

05
05







END AQUIFER SPECIFIC VARIABLE  DATA
END ALL DATA
                                                                             128

-------
The type of distribution associated with each parameter is indicated in the
"Distribution" column.  The number assigned to each of the distribution types is
shown in Table A-4.  A value of 0 in the "Distribution" column indicates a
constant value for the parameter.  A value of -1 or -2 indicates that the
parameter is derived from other parameters in the code.  As Table A-4 indicates,
other values are used for Monte Carlo distributions.  For example,  the saturated
hydraulic conductivity for Material 1 in the unsaturated zone has a value of 2 in
the "Distribution" column, which indicates that a lognormal probability density
distribution has been assigned to the parameter.

7.3.3  Output

The output from MULTIMED is presented in Tables 7-9 through 7-11.  Because the
General Data Group flag for the level of output from Monte Carlo runs was set to
SOME for this example problem  (see Section 5.3.2.2), the output consists of the
main output file, the STATS.OUT file, and the SAT1.OUT file.   The main output
file consists of an echo of the input parameters, selected statistical results,
and printer plots of frequency and cumulative frequency.  The STATS.OUT file
contains a summary of the statistical analyses resulting from the Monte Carlo
simulations.  The cumulative distribution function of well concentrations (i.e.,
well concentrations in ascending order)  is listed in the SAT1.0UT file.  This
file can be used by the postprocessor,  POSTMED, to produce frequency and
cumulative frequency plots of higher quality than those found in the main output
file.  Examples of these plots are shown in Section 4.2.
                                       129

-------
TABLE 7-9.  MAIN OUTPUT FILE FOR EXAMPLE 3.
                         U. S.    ENVIRONMENTAL   PROTECTION   AGENCY

                                         EXPOSURE   ASSESSMENT

                                            MULTIMEDIA   MODEL

                                               VERSION 3.3, DECEMBER 1988

                                   Developed by Phillip Mineart and Atul Salhotra of
                                    Woodward-Clyde Consultants, Oakland, California
                                                  In cooperation with:
                                        Hydrogeologic, Inc.,  Herndon, Virginia,
                                           Geotrans, Inc.,  Herndon, Virginia,
                                                          and
                                   Aqua Terra Consultants,  Mountain View, California
 Run options
 Example 3 input
 Subtitle D application
 Chemical simulated is DEFAULT CHEMICAL
 Option Chosen
 Run was
 Infiltration input by user
 Number of monte carlo simulations       500
 Run was steady-state
 Rej ect runs if Y coordinate outside plume
 Rej ect runs if Z coordinate outside plume
 Gaussian source used in saturated zone model
Saturated and unsaturated zone models
MONTE
 UNSATURATED ZONE FLOW MODEL PARAMETERS
 (input parameter description and value)
 NP     - Total number of nodal points
 NMAT   - Number of different porous materials
 KPROP  - Van Genuchten or Brooks and Corey
 IMSHGN - Spatial discretization option
        1
                 240
                   1
                   1
                   1
                                                                                                                                  (continued)
                                                                           130

-------
TABLE 7-9.  MAIN OUTPUT FILE FOR EXAMPLE 3.
 OPTIONS CHOSEN
 Van Genuchten functional coefficients
 User defined coordinate system
 Layer information

 LAYER NO.    LAYER THICKNESS

     1                   0.00
MATERIAL PROPERTY

         1
                                                      DATA  FOR  MATERIAL   1

                                                  VADOSE  ZONE MATERIAL VARIABLES
VARIABLE NAME

Saturated hydraulic conductivity
Unsaturated zone porosity
Air entry pressure head
Depth of the unsaturated zone
UNITS

cm/hr
--
m
m
DISTRIBUTION

LOG NORMAL
NORMAL
CONSTANT
CONSTANT
PARAMETERS

0
0
0

MEAN
.170E-01
.330
.OOOE+00
6.10

0
0
-
-
STD DEV
.200E-01
.100
999.
999.

0
0
0
0
LIMITS
MIN
.100E-
.200
.OOOE+
. 100E-

03

00
08

0
0
-
-
MAX
.250
.450
999.
999.
                                                      DATA  FOR  MATERIAL   1

                                                  VADOSE  ZONE FUNCTION VARIABLES
                       VARIABLE NAME
                                                    UNITS
                                                                DISTRIBUTION
                                                                                      PARAMETERS
                                                                                    MEAN     STD DEV
                                                                            LIMITS
                                                                        MIN          MAX
           Residual water content
           Brook and Corey exponent,EN
           ALFA coefficient
           Van Genuchten exponent, ENN
                  I/cm
CONSTANT
CONSTANT
CONSTANT
CONSTANT
0.880E-01 -999.
0.500     -999.
0.900E-02 -999.
 1.23     -999.
0.100E-08   1.00
0.OOOE+00   10.0
0.OOOE+00   1.00
 1.00       5.00
                                                                                                                                  (continued)
                                                                            131

-------
TABLE 7-9.  MAIN OUTPUT FILE FOR EXAMPLE 3.
UNSATURATED ZONE TRANSPORT MODEL PARAMETERS

 NLAY   - Number of different layers used                 1
 NTSTPS - Number of time values concentration calc       20
 DUMMY  - Not presently used                              1
 ISOL   - Type of scheme used in unsaturated zone         1
 N      - Stehfest terms or number of increments         18
 NTEL   - Points in Lagrangian interpolation              3
 NGPTS  - Number of Gauss points                        104
 NIT    - Convolution integral segments                   2
 IBOUND - Type of boundary condition                      1
 ITSGEN - Time values generated or input                  1
 TMAX   - Max simulation time             --             0.0
 WTFUN  - Weighting factor                --             1.2
 OPTIONS CHOSEN

 Stehfest numerical inversion algorithm
 Nondecaying continuous source
 Computer generated times for computing concentrations
                                                      DATA FOR LAYER   1

                                                      VADOSE TRANSPORT VARIABLES
                       VARIABLE NAME
                                                    UNITS
                                                               DISTRIBUTION
                                                                                     PARAMETERS
                                                                                   MEAN     STD DEV
    LIMITS
MIN         MAX
Thickness of layer
Longitudinal dispersivity of layer
Percent organic matter
Bulk density of soil for layer
Biological decay coefficient
m
m
--
g/cc
1/yr
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT

0
0

0
6


1

.10
400
260E-
.45
OOOE+


01

00
-999.
-999.
-999.
-999.
-999.
0
0
0
0
0
.100E-08
.OOOE+00
.OOOE+00
. 100E-01
.OOOE+00
-999.
0.100E+
100.
5.00
-999.

05



                                                                                                                                 (continued)
                                                                           132

-------
TABLE 7-9.   MAIN OUTPUT FILE FOR EXAMPLE  3.
                                                     CHEMICAL  SPECIFIC VARIABLES
VARIABLE NAME
LIMITS

Solid phase decay coefficient
Dissolved phase decay coefficient
Overall chemical decay coefficient
Acid catalyzed hydrolysis rate
Neutral hydrolysis rate constant
Base catalyzed hydrolysis rate
Reference temperature
Normalized distribution coefficient
Distribution coefficient
Biodegradation coefficient (sat. zone)
Air diffusion coefficient
Reference temperature for air diffusion
Molecular weight
Mole fraction of solute
Vapor pressure of solute
Henry "s law constant
RFD value for drinking water
ADIF value for fish consumption
CCC for aquatic organisms
UNITS


1/yr
1/yr
1/yr
1/M-yr
1/yr
1/M-yr
C
ml/g

1/yr
cm2/s
C
g/M
--
mm Hg
atm-mA3/M
mg-kg/day
mg-kg/day
mg-kg/day
DISTRIBUTION

MEAN
DERIVED
DERIVED
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT
CONSTANT

STD DEV
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
25.0
140.
0.219
O.OOOE+00
O.OOOE+00
O.OOOE+00
-999.
-999.
-999.
-999.
1.00
1.00
1.00
PARAMETERS

MIN MAX
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
0.645E-02 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
0.100E-01 0.100E-08
0.230E-01 O.OOOE+00
O.OOOE+00 0.100E-09
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00
O.OOOE+00 O.OOOE+00



0.100E+11
0.100E+11
0.100E+11
-999.
-999.
-999.
100.
-999.
0.100E+11
-999.
10.0
100.
-999.
1.00
100.
1.00
1.00
1.00
1.00
SOURCE SPECIFIC VARIABLES
VARIABLE NAME
Infiltration rate
Area of waste disposal unit
Duration of pulse
Spread of contaminant source
Recharge rate
Source decay constant
Initial concentration at landfill
Length scale of facility
Width scale of facility
Near field dilution
UNITS DISTRIBUTION
m/yr
m~2
yr
m
m/yr
1/yr
mg/1
m
m

CONSTANT
CONSTANT
CONSTANT
DERIVED
CONSTANT
CONSTANT
CONSTANT
DERIVED
DERIVED
CONSTANT
PARAMETERS
MEAN STD DEV
0.700E-02 -999.
400. -999.
-999. -999.
-999. -999.
0.160E-01 -999.
O.OOOE+00 -999.
1.00 -999.
-999. -999.
-999. -999.
O.OOOE+00 O.OOOE+00
LIMITS
MIN MAX
0.100E-09 0.100E+11
0.100E-01 -999.
0.100E-08 -999.
0.100E-08 0.100E+11
0.100E-09 0.100E+11
O.OOOE+00 -999.
O.OOOE+00 -999.
0.100E-08 0.100E+11
0.100E-08 0.100E+11
O.OOOE+00 O.OOOE+00











                                                                                                                                (continued)
                                                                           133

-------
TABLE 7-9.  MAIN OUTPUT  FILE FOR EXAMPLE 3.
                                                       AQUIFER  SPECIFIC VARIABLES
VARIABLE NAME
Particle diameter
Aquifer porosity
Bulk density
Aquifer thickness
Source thickness (mixing zone
Conductivity (hydraulic)
Gradient (hydraulic)
Groundwater seepage velocity
Retardation coefficient
Longitudinal dispersivity
Transverse dispersivity
Vertical dispersivity
Temperature of aquifer
pH
UNITS
cm
--
g/cc
m
depth) m
m/yr

m/yr
--
m
m
m
C
--
Organic carbon content (fraction)
Well distance from site
Angle off center
Well vertical distance
0 Values generated which exceeded
m
degree
m
the specified bounds.
PI
DISTRIBUTION
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
CONSTANT
DERIVED
DERIVED
NORMAL
CONSTANT
CONSTANT
CONSTANT
UNIFORM
CONSTANT
CONSTANT
CONSTANT
CONSTANT
rQTTT.TQ
PARAMETERS
MEAN STD DEV
0.630E-03
-999.
-999.
78.6
-999.
-999.
0.306E-01
-999.
-999.
160.
15.2
8.00
14.4
-999.
0.315E-02
152.
O.OOOE+00
O.OOOE+00

-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
15.0
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

LIMITS
MIN MAX
0.100E-08
0.100E-08
0.100E-01
0.100E-08
0.100E-08
0.100E-06
0.100E-07
0.100E-09
1.00
50.0
0.100E-02
0.100E-02
O.OOOE+00
5.80
0.100E-05
1.00
O.OOOE+00
O.OOOE+00

100.
0.990
5.00
0.100E+06
0.100E+06
0.100E+09
-999.
0.100E+09
0.100E+09
200.
0.100E+05
0.100E+05
100.
6.90
1.00
-999.
360.
1.00

                                                      SATURATED  ZONE  TRANSPORT
                      Example 3  input

                      Subtitle D application
                                                N                         =   500
                                                MEAN                      =  0.573E-03
                                                STANDARD DEVIATION       =  0.346E-04
                                                COEFFICIENT OF VARIATION =  0.604E-01
                                                MINIMUM VALUE             =  0.475E-03
                                                MAXIMUM VALUE             =  0.657E-03
                                                50th PERCENTILE           =  0.573E-03
                                                80th PERCENTILE           =  0.602E-03
                                                85th PERCENTILE           =  0.608E-03
                                                90th PERCENTILE           =  0.619E-03
                                                95th PERCENTILE           =  0.634E-03
                                                                                         90. PERCENT CONFIDENCE  INTERVAL
0.570E-03
0.599E-03
0.605E-03
0.614E-03
0.626E-03
0.576E-03
0.605E-03
0.614E-03
0.623E-03
0.640E-03
                                                                                                                       (continued)
                                                                             134

-------
TABLE 7-9.  MAIN OUTPUT  FILE FOR EXAMPLE 3.
                                    -999 UNABLE TO COMPUTE  CONFIDENCE BOUND DUE TO INSUFFICIENT DATA
                                      VALUE       % OF TIME  EQUALLED  % OF TIME IN INTERVAL
                                                      OR  EXCEEDED
                                    0.100E-03        100.000
                                                                              0.000
                                    0.156E-03        100.000
                                                                              0.000
                                    0.211E-03        100.000
                                                                              0.000
                                    0.267E-03        100.000
                                                                              0.000
                                    0.323E-03        100.000
                                                                              0.000
                                    0.378E-03        100.000
                                                                              0.000
                                    0.434E-03        100.000
                                                                              0.800
                                    0.490E-03         99.200
                                                                             21.400
                                    0.546E-03         77.800
                                                                             56.800
                                    0.601E-03         21.000
                                                                             20.800
                                    0.657E-03           0.200
                                                                                                                                     (continued)
                                                                             135

-------
TABLE 7-9.  MAIN OUTPUT FILE FOR EXAMPLE  3.
   100
    80
 F
 R
 E
 Q  60
 U
 E
 N
 C  40
 Y
    20
     0 +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +
    0.100  0.156  0.211  0.267  0.323   0.378   0.434   0.490  0.546  0.601  0.657
                                   *   0.1E-02

                                CONCENTRATION
                                                                                                                                   (continued)
                                                                            136

-------
TABLE 7-9.  MAIN OUTPUT FILE FOR EXAMPLE 3.
1
C 100 +--
U !
M !
U !
L 80 +--
A !
T !
I !
V 60 +--
E !
F !
R 40 +--
E !
Q !
U !
E 20 +--
N !
C !
Y !
0 +**
0.100


	 H 	 H 	 H 	 H 	 H 	 H 	 H 	 H 	 H 	 **
*** i
* i
* i

i
* i
* i

* i
i
* i

i
* i
i

* i
* i
** i

0.156 0.211 0.267 0.323 0.378 0.434 0.490 0.546 0.601 0.657
* 0.1E-02
                                CONCENTRATION
                                                                                                                                  (continued)
                                                                            137

-------
TABLE 7-9.  MAIN OUTPUT FILE  FOR  EXAMPLE  3.
 FOLLOWING GRAPHS ARE FOR THE TOP  20%  OF THERESULTS
1
   100 +	H	H	H	H	H	H- -
    80
 F
 R
 E
 Q  60
 U
 E
 N
 C  40
 Y
    20
     0 +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +	*__ +
    0.100  0.156  0.211  0.267   0.323   0.378   0.434  0.490  0.546  0.601  0.657
                                   *   0.1E-02

                                 CONCENTRATION
                                                                                                                                   (continued)
                                                                            138

-------
TABLE 7-9.  MAIN  OUTPUT FILE FOR EXAMPLE  3   (concluded).
1
C 100 +--
U !
M !
U !
L 80 +--
A !
T !
I !
V 60 +--
E !
F !
R 40 +--
E !
Q !
U !
E 20 +--
N !
C !
Y !
0 +**
0.100



* !
i
* i

* i
i
* i

i
i
i

i
i
* i

i
i
i
************************************************************ 	 +
0.156 0.211 0.267 0.323 0.378 0.434 0.490 0.546 0.601 0.657
* 0.1E-02
                                 CONCENTRATION
                                                                              139

-------
TABLE 7-10.   FIRST PAGE OF THE SAT1.OUT FILE FOR EXAMPLE  3.
    0.47457E-03
    0.47974E-03
    0.48608E-03
    0.48800E-03
    0.49012E-03
    0.49224E-03
    0.49897E-03
    0.49929E-03
    0.49976E-03
    0.50186E-03
    0.50328E-03
    0.50413E-03
    0.50599E-03
    0.50715E-03
    0.50830E-03
    0.50845E-03
    0.50892E-03
    0.50896E-03
    0.50899E-03
    0.50927E-03
    0.50953E-03
    0.51086E-03
    0.51110E-03
    0.51265E-03
    0.51344E-03
    0.51375E-03
    0.51534E-03
    0.51589E-03
    0.51801E-03
    0.51807E-03
    0.51846E-03
    0.52211E-03
    0.52246E-03
    0.52261E-03
    0.52275E-03
    0.52347E-03
    0.52361E-03
    0.52425E-03
    0.52430E-03
    0.52450E-03
    0.52490E-03
    0.52494E-03
    0.52552E-03
    0.52583E-03
    0.52599E-03
    0.52603E-03
    0.52615E-03
    0.52751E-03
                                                                               140

-------
TABLE 7-11.  STATS.OUT FILE  FOR  EXAMPLE 3.
                     Example  3  input

                     Subtitle D application
                                                              RESULTS
                                                      SATURATED ZONE TRANSPORT
                                                N
                                                MEAN
                                                STANDARD DEVIATION
                                                COEFFICIENT OF VARIATION =
                                                MINIMUM VALUE
                                                MAXIMUM VALUE
                                                50th PERCENTILE
                                                80th PERCENTILE
                                                85th PERCENTILE
                                                90th PERCENTILE
                                                95th PERCENTILE
                                    -999  UNABLE TO COMPUTE CONFIDENCE BOUND DUE TO  INSUFFICIENT DATA
                                                                                         90.  PERCENT CONFIDENCE INTERVAL

0
0
0
0
0
0
0
0
0
0
500
.573E
.346E
.604E
.475E
.657E
.573E
.602E
.608E
.619E
.634E

-03
-04
-01
-03
-03
-03
-03
-03
-03
-03






0
0
0
0
0






.570E
.599E
.605E
.614E
.626E






-03
-03
-03
-03
-03






0
0
0
0
0






.576E
.605E
.614E
.623E
.640E






-03
-03
-03
-03
-03
                                      VALUE
                                                    OF TIME EQUALLED  % OF TIME  IN  INTERVAL
                                                      OR EXCEEDED
0

0

0

0

0

0

0

0

0

0

0
. 100E-

.156E-

.211E-

.267E-

.323E-

.378E-

.434E-

.490E-

.546E-

. 601E-

.657E-
03

03

03

03

03

03

03

03

03

03

03
100.

100.

100.

100.

100.

100.

100.

99.

77.

21.

0.
.000

.000

.000

.000

.000

.000

.000

.200

.800

.000

.200

0

0

0

0

0

0

0

21

56

20


.000

.000

.000

.000

.000

.000

.800

.400

.800

.800

                                                                             141

-------
                                    APPENDIX A
                       CODE STRUCTURE AND INPUT DATA FORMAT
MULTIMED consists of a number of modules, the theoretical details of which are
described in Salhotra et al.   (1990).   It is important for the user to understand
the capabilities and limitations of these modules.  However, because an
interactive preprocessor, PREMED, has been developed to create or edit input, the
average user need not understand the format of the input files or the structure
of the code.  For advanced users, who wish to modify the code or to examine the
input files without the use of the preprocessor, this chapter provides an
overview of the code structure and input file format.  Much of the information in
this appendix is based on material in Salhotra and Mineart  (1988).   No
information about the pre- and postprocessors for MULTIMED is included.

A.I  MODEL STRUCTURE

The code consists of a number of subroutines.  The organization of the
subroutines is shown in Figure A.I.  In addition, a list of all the subroutines,
the calling subroutine/program, and a brief description of the subroutines is
included in Appendix B.  Each subroutine includes several comment statements that
describe the function of the subroutine.  The arguments of each subroutine are
divided into three categories:  1) arguments that are passed to the subroutine by
the calling program, 2) arguments that are modified within the subroutine, and 3)
arguments returned by the subroutine to the calling program.

A.2  INPUT AND OUTPUT FILE UNITS

To run the model, one or two input files are needed,  depending on the options
selected by the user.  The location of the open statements for these files, the
default unit numbers, file names, and contents are shown in Table A-l.

The model generates a number of output files.  The location of the open
statements for these files, the associated default unit numbers, file names, and
a brief description are given in Table A-2.

The user specifies the name of the main output file.   In deterministic mode, this
file contains an echo of the input data and the calculated contaminant
concentration(s) at the receptor(s) of interest.  In Monte Carlo mode, the file
consists of an echo of input parameters, selected statistical results, and
printer plots of frequency and cumulative frequency.

Two additional types of files are also generated.  These are designated as the
*.VAR and *.OUT files, where the "*"  refers to a specific type of data for the
                                        148

-------
MAIN  ) ) ) ,
/) OPENF
/) SOPEN
/) COUNT
/) MODCHK        +)
/) RANSET        /)
/) PRTOUT) ))))))/)
/)))))))))))))))/)
/) PRTINP))0))))-
                              ADPRNT
                              PRNEMP
                              PRNEMP
                              PRINTO
                                               PRNTVZ) )))))!
/) OUTPUT) )))))) 0)
                  .)
/) AQNAMS
/) ARNAMS
/) CHNAMS
/) LFNAMS
/) SONAMS
/) STNAMS
/) VFNAMS
/) VTNAMS
/) DEFAULTS
/) INITGW
/) INITAR        +)
/) INITVF)))))))2)
*
                  +)
                  /)
/) INITVT)))))))3)
                  /)
                  .)
*
/) INITST)))))))))
*
/) UNCPRO)))))))))
                              FRQTAB
                              FRQPLT
                              +) PRINTO
                              I
                              .) PRNEMP
DISC
INITLF))))))))   LINER1

LINV))))))))))   FACTR
LAYAVE
TMGEN1
TMGEN2
TMGEN3

REOX

CALLS)))))))0)   TRNLOG
             /)  TRANSB
             /)  EXPRND))))))))
             /)  NORMAL)))))),
             /)  LOGNOR) ) ) ) ) ) 2)
             /)  EMPCAL)))))),
                                                               EXPRN)) ,
                                                                       *
                                                               ANRMRN) 1
                                                                       *
                                                               UNIFRM)!
                                                                          UNIFRN
Figure A.I  Subroutine  organization tree  for MULTIMED (from Salhotra
             and Mineart,  1988).
                                                                 (continued)
                                            149

-------
MAIN)))),                  +)  ADISRD))))))0))))))))))))))))
         /)  BATIN))))))))3)   LEFTJT       *
         *                 /)  CHKEND))))))!
                                               READ2))))))),
                                               READ3)))))))3)
         /)  ARCALC
         /)  AIRIN))))))))))
                                                       COMRD
                                                       ICHECK
                     COMRD
                     VIRT
                     SIGMAZ
/)))))))))))))))<>)    VFCALC))))))0)
                  /)  PERC))))))))2)
/) LFCALC)))))))3)   EVPT
*                 . )  RUNOFF
*
/)
                                               WCFUN
                                               RAPSON))))))))
FPSI1
         /)  GWCALC)))) 0)   CONVO2)))  CPCAL)0)))))))))))   GW3DPT
         *             /)  GW3DPT) ,          *
         *             /))))))))) 2)))))))) 2)    GW2DFT)0)  QROMB)0)  TRAPZD) ,
                       /))))))))),                      -))))))))2)))))))))2)
                       .)  GW3DPS)2)  GW2DFS))))))))))))))))))))))))))))),
                                                                       FUNCTI
*
/)
*
*
*
*
*
*
*
*
*
*
*

VTCALC) ) ) ) 0)
/)
/)
/)
/)
*
*
/)
•)




ADVECT
ADISPR
COEF
STEHF
SOLAY1))) EXPERF)


CONVO1) ,
SOLBT))2)))))))))3)







+)
*
.)

+)

/)
*
.">
                                                 DERFC
                                                 EXPD
                                                                    /)  DGAUSS
                                                 EVAL                        *
                                                 LAGRNG                     *
                                                 SOLAY1))  EXPERF)0)  DERFC *
                                                                   .)  EXPD   *
            PATCH)))))0)
                           +)  CINTER
                           /)  CMIX
            SWCALC) )))))) 3)   TRANS
                           /)  DRINK
                           .)  FISH
                                              .)  DBK1
                                             )))))))))
                                              .)  ERFC
Figure A.I  Subroutine  organization tree  for MULTIMED  (from Salhotra
             and Mineart,  1988).   (concluded)
                                            150

-------
Table A-l.  INPUT FILES NEEDED IN MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444
Opened In      Unit        Name                    Description
MAIN
ADISRD
               IOUT7=7
            USER-SPECIFIED
IUNT28=28   FREQ.IN
Main input file.  Required
to run the model .

Contains information
describing the wind-
stability joint frequency
distribution for
contaminant transport
in the air (see Section
A. 5. 9.1) .
.VAR files and a specific module for the  .OUT files.  The  *.VAR  files  contain  the
values of the randomly-generated variables, any derived variables used for  each
Monte Carlo simulation run, and the values of any deterministic  variables.   The
.OUT files contain the model results for  each Monte Carlo  simulation.   Thus, for
typical Monte Carlo simulations, these files will contain  500 to 2000  values.
Results of statistical analyses  (mean, median, and percentiles)  of  the values  in
the *.OUT files are included in the main  output file and in the  file STATS. OUT.

The BATCH. ECH file contains an echo of all the data in the input file  and
includes any error messages generated while reading the data.  Errors  in reading
the data will stop execution of the program.

Two of the output files may be used with  the postprocessor, POSTMED.   The data in
SAT1.0UT can be used by the postprocessor to generate frequency  and cumulative
frequency plots.  For transient, deterministic simulations, plots of
concentration versus time can be generated by the postprocessor  using  data  in  the
main input file.

A. 3  COMMON BLOCKS AND PARAMETER STATEMENTS

Most variables are passed between subroutines through the  use of common blocks.
There are a total of 54 common blocks in  the model  (i.e.,  excluding those
associated with the pre- and postprocessors) , each containing a  related set  of
variables.  The common blocks are contained in files which are accessed by  the
code during compilation through the use of INCLUDE statements located  at the
beginning of each subroutine.

Parameter statements are used to define all I/O  (Input/Output) unit numbers  and
array dimensions in the model.  Any array dimensions or I/O numbers can be
changed by assigning a new value to the variable in the appropriate parameter
statement.  The entire code must be recompiled and linked  if changes are made  to
any parameter statement.
                                       151

-------
TABLE A-2.  OUTPUT FILES GENERATED BY MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444
Opened In      Unit            Name                 Description
MAIN

SOPEN




SOPEN




SOPEN
IOUT = 1       user-specified

IUNT8 = 8      AQUIFER.VAR




IUNT13 = 13    CHEMICAL.VAR




IUNT14 = 14    SOURCE.VAR
                                   Main  output  file.

                                   Values  of  aquifer  variables
                                   generated  for Monte Carlo
                                   simulations.

                                   Values  of  chemical variables
                                   generated  for Monte Carlo
                                   simulations.

                                   Values  of  source variables
                                   generated  for Monte Carlo
                                   simulations.
SOPEN
SOPEN
SOPEN
SOPEN
BAT IN
SOPEN
SOPEN
IUNT15 = 15    SURFACE.VAR
IUNT16 = 16    VFLOW.VAR
IUNT17 = 17    VTRNSPT.VAR
IUNT18 = 18    AIR.VAR
                BATOUT =19    BATCH.ECH
VFOUT = 20     VFLOW.OUT
VTOUT =21     VTRNSPT.OUT
                                  Values of  surface  water
                                  variables  generated for Monte
                                  Carlo simulations.

                                  Values of  unsaturated zone
                                  material variables and
                                  functional parameters generated
                                  for Monte  Carlo  simulations.

                                  Values of  unsaturated zone
                                  transport  variables generated
                                  for Monte  Carlo  simulations.

                                  Values of  Air  Emissions and
                                  Dispersion Module  variables
                                  generated  for  Monte Carlo
                                  simulations.

                                  Echo of the batch  input file
                                  and list of any  errors in the
                                  input data.

                                  Results from the Unsaturated
                                  Zone Flow  Module.

                                  Concentrations at  the water
                                  table computed by  the
                                  Unsaturated Zone Transport
                                  Module.

                                  (continued)
                                        152

-------
TABLE A-2.  OUTPUT FILES GENERATED BY MULTIMED  (concluded)
4444444444444444444444444444444444444444444444444444444444444444444
Opened In      Unit            Name                 Description
SOPEN
SOPEN
SOPEN
MAIN
MAIN
SOPEN
SOPEN
SOPEN
STOUT =22     SAT.OUT
AROUT =23     AIR.OUT
STOUT2 =24    SURFACE.OUT
                ISTAT =25      STATS.OUT
                IUNT27 =27     SAT1.OUT
IUNT29 =29    LANDFM.VAR
IUNT30 =30    LANDFL.VAR
IUNT31 =31    LANDFH.VAR
Downgradient well
concentrations computed by
Saturated Zone Transport
Module.

Results from Air Emissions
Module and the receptor
concentrations for the Air
Dispersion Module.

Results from the Surface
Water Module.

Summary statistics of the
receptor concentrations
(groundwater, atmosphere,
surface stream).

Downgradient well
concentrations sorted in
ascending order  (CDF of
concentrations).

Values of landfill material
parameters generated for
Monte Carlo simulations.

Values of liner properties
generated for Monte Carlo
simulations.

Values of hydrology para-
meters generated for Monte
Carlo simulations.
The main output contains an echo of  the  input  data,  printer plots,  and
selected statistical parameters of the results of  the Monte Carlo
simulations.  In addition, a  summary output  file  is  created on unit ISTAT.
                                        153

-------
A.4  STRUCTURE OF THE INPUT FILES

The overall structure of the main input file is shown in Figure A. 2.  The first
two cards contain the title of the simulation.   The remaining cards in the file
contain the data necessary to run MULTIMED.  These data are clustered into a
number of groups, each of which contains a specific type of data that is input
using one or more DATA CARDS.  The data groups are divided into subgroups, with
each subgroup containing a set of data specific to the group within which the
subgroup is located.  The structure of each data group/subgroup is illustrated in
Figure A.2.  In addition to the DATA CARDS, the input file contains DATA
GROUP/SUBGROUP SPECIFICATION CARDS, END CARDS,  and if desired, one or more
COMMENT CARDS.

The data for the model are divided into nine major groups.  These groups are
listed in Table A-3 along with the appropriate code for the GROUP SPECIFICATION
CARD.  Each data group is read in as a unit, with the beginning identified by the
GROUP SPECIFICATION CARD and the end by the END CARD.  The data cards are
sandwiched between these two cards.  Further,  the data group may contain one or
more subgroups that are also listed in Table A-3.  Note that the structure of a
subgroup is exactly the same as that for a group--!.e., a subgroup is identified
by a SUBGROUP SPECIFICATION CARD and terminated by an END CARD, with the subgroup
data sandwiched between the two cards.  A data file need contain only those data
groups (and subgroups within a data group) that are necessary to run the options
selected by the user.

The options selected by the user and indicated in the General Data Group will
determine which additional groups of data are necessary.  For example, if the
user has specified within the General Data Group that only the Saturated Zone
Transport Module will be run, the Unsaturated Zone Flow and Transport Data Groups
(VFL, VTP)  are not necessary.  Also note that the structure of the input file
allows the required data groups to be arranged in any order.

A.4.1  Comment Cards

COMMENT CARDS are indicated by the presence of three asterisks, '***'.  The group
Of T***T  can ke input starting at any column of the card but must be the first
three non-blank characters.  The COMMENT CARDS are useful for separating data
types and can be used to include other helpful comments.  Note that there are no
restrictions as to the location and number of COMMENT CARDS, except that they
cannot be the first two cards in the data file.

A.4.2  Data Group/Subgroup Specification Card,  End Card, and Data Cards

The DATA GROUP/SUBGROUP SPECIFICATION CARD indicates the beginning of a specific
data group and includes the Group  (Subgroup) Specification Code (Table A-3)  in
columns 1 to 3.   For example, if the DATA GROUP SPECIFICATION CARD contains the
letters TAQUT in columns 1 to 3,  it implies that the following cards, up to and
including the corresponding  'END' card, contain aquifer data.

With the exceptions discussed in Section A.5,  each DATA CARD contains information
about one variable only.  Typically the card will contain the variable
                                       154

-------
Figure A.2
                                       155

-------
Table A-3.  INPUT DATA GROUPS AND SUBGROUPS IN MULTIMED
4444444444444444444444444444444444444444444444444444444444444444444
Data Group                                   Group  Specification  Code
1.   General Data                                  GEN
2 .   Source Data                                   SOU
3.   Landfill Data                                 LFL
4.   Chemical Data                                 CHE
5.   Unsaturated Zone Flow Data                    VFL
6.   Unsaturated Zone Transport Data               VTP
7.   Aquifer Data                                  AQU
8.   Surface Water Data                            SUR
9.   Air Emissions and Dispersion Data             AIR
Subgroups                                    Subgroup  Specification  Code
1.   Array Data                                    ARR
2.   Empirical Distribution Data                   BMP
3 .   Control Data                                  CON
4.   Spatial Discretization Data                   SPA
5.   Material Property Data                        SAT
6.   Material Specification Data                   MAT
7.   Unsaturated Zone Moisture Data                SOI
8.   Unsaturated Zone Transport Properties Data    TRA
9.   Unsaturated Zone Time Stepping Data           TIM
10.  Landfill Liner Data                           LIN
11.  Layer Identification Data                     LAY
12 .  Hydrology Data                                HYD
specification index, variable name, Monte Carlo distribution  type,  distribution
parameters, and the upper and lower bounds of the distribution.   To the  extent
possible, consistent formats for the DATA CARDS have been maintained for the
different data groups.

The termination of a data group and/or a subgroup is indicated by the END CARD,
which contains the word END in the first three columns.

A. 4. 3  Specification of Parameter Values

within each group, except the General Data Group, there  are a number of  variables
whose value can be specified in one of three ways:  1) the variable may  be
assigned a constant value, 2) the variable may be derived within  the code using
functional relations- -for example, the aquifer porosity  may be derived from the
particle diameter, or 3) the variable may be assigned  a  distribution and the
value randomly generated in the Monte Carlo simulation.  The  numerical codes
associated with each distribution type are listed in Table A-4.   Depending on
                                        156

-------
Table A-4.  DISTRIBUTIONS AVAILABLE AND THEIR CODES
4444444444444444444444444444444444444444444444444444444444444444444
Distribution Type                      Distribution  Code
   Constant                                   0
   Normal                                     1
   Lognormal                                  2
   Exponential                                3
   Uniform                                    4
   LoglO Uniform                              5
   Empirical                                  6
   Johnson SB                                 7
   Gelhara                                    8
   Derived Dispersivityb                      10
   Derived Variable0                          -1
  a       Gelhar's distribution applies only to the  saturated  zone  dispersivities .
         For details, refer to Section 6.5.10.

  b       The derivation of the saturated  zone dispersivities  using distribution
         code 8 is described in Section 5.5.3.5 of  Salhotra et  al .  (1990).

  c       For parameters other than the spread of the  source or  the source
         thickness  (mixing zone depth), a  -2 is interchangeable with  a  -1.

Note:    The seven Monte Carlo distributions  (distribution code 1-7)  are
         described in Section 9.4 of Salhotra et al .  (1990).
the distribution selected for a particular variable,  the  required  input  data  will
vary.  Refer to Section 9.4 of Salhotra et al .  (1990)  for information  about the
seven Monte Carlo distribution options.  Section  5.5.3.5  of  Salhotra et  al .
(1990) or Section 6.5.10 of this document explain the Gelhar distribution  and the
derivation of dispersivity .

A. 4. 4  The Array Subgroup

The contents and format for the Array Subgroup  are  shown  in  Table  A-5.   The first
card is the SUBGROUP SPECIFICATION CARD, with the code ARR in the  first  three
columns.  This card is followed by one card  for each  variable in the group.
Those cards contain values/distributions, and lower and upper bounds for the
indicated variables.  For example, when the  ARR subgroup  is  included within the
Aquifer Group Data, the subgroup will contain cards describing the aquifer-
specific variables such as porosity, dispersivities,  etc.  The specific  variables
within each group are discussed in Section A. 5.   Note that the number  of cards
within the Array Subgroup varies because the various  groups  and subgroups  have
different numbers of input variables.  The variable being input is identified by
the value of the Index I .
                                        157

-------
Table A-5.  CONTENTS AND FORMAT OF A TYPICAL ARRAY  SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format
Al

A2


A3

Note:
         "ARR"

         I, NAME (I), NDSTPRM(I), ARRPRM (I , 1)
         ARRPRM(I,2), BOUND (1,1), BOUND (I, 2)
                                                   A3

                                                   12,  IX,  A5 0 ,  7X,
                                                   110,  5X,  4F10.0
         "END"                                     A3

          Card/line A2 is repeated  for each variable within  the  group.
               Definition of Contents
"ARR
NAME (I)
               Subgroup Specification Card  indicating  the  start  of  the  Array
               Subgroup.

               Integer which identifies the variable being input.   See  the
               individual data group tables for  the values of  I  for specific
               variables.  Note that I is not  a  counter.

               Name of variable I.  It is used to  identify the variables  in the
               output files.
NDSTPRM(I)     Integer which identifies the  type  of  distribution  used for
         variable I  (e.g., constant, derived, or  one of  the  Monte Carlo
         distributions). See Table A-4.

ARRPRM (1,1)    Mean value for variable I.

ARRPRM (I, 2)    Standard deviation for variable  I.

BOUND (1,1)     Minimum allowed value  (lower  bound) for variable I.

BOUND (I, 2)     Maximum allowed value  (upper  bound) for variable I.

"END"          End Card indicating the end of the Array  Subgroup.
The value of the integer variable NDSTPRM(I)  in Table A-5  indicates  the  type of
distribution chosen for the variable identified by  the  index  I.   The available
options and values of the integer variable NDSTPRM(I) are  listed  in  Table  A-4.
If any of the variables are specified to have an  Empirical  distribution
(NDSTPRM(I)  = 6), then it is necessary to include the EMPIRICAL SUBGROUP,  the
details of which are described in Section A. 4. 5.  Note  that if the variable is
specified to be a constant  (NDSTPRM(I) = 0),  the  value  input  as mean for the
corresponding variable (ARRPRM (I , 1) ) is used  in the simulations.  The end  of the
Array Subgroup is indicated by an END CARD.

A. 4. 5  The Empirical Distribution Subgroup

The contents and format for the  Empirical Distribution  Subgroup are  shown  in
Table A-6.  The first card is the SUBGROUP SPECIFICATION CARD, with  the  code BMP
in the first three columns.  The next card identifies the  variable  (using  the
index I)  that has an empirical distribution and the number  of coordinates  of the
empirical cumulative distribution function that are being  input.  A  maximum of 20
coordinates can be input.

The next set of cards  (two cards, if fewer than 10  coordinate pairs  are  input,  or
four cards,  if more than 10 coordinate pairs  are  input) contain the  probabilities
                                        158

-------
(in ascending order) and the corresponding values of the variable.  Variable
values corresponding to cumulative probability values of zero and unity must be
provided.  Note that all the cumulative probability coordinate values are first
input, followed by an equal number of the corresponding variable values.  The
above procedure is repeated for each of the variables that have empirical
distributions.  The end of the subgroup is indicated by the END CARD.

A.5  FORMAT OF THE DATA GROUPS

As was stated above, DATA CARDS 1 and 2 contain the title of the run, with a
maximum of 80 columns per card.  DATA CARDS 3 through the end contain data
specific to one or more groups/subgroups.  The specific formats for each data
group are described below.  The data groups do not have to be input in the order
in which they are discussed.  However,  it is recommended that the General Data
Group be input first.  An END CARD must be put at the end of the data file
following the end of the last data group.

A.5.1  General Data Group

The contents and format of the General  Data Group are shown in Table A-7.  This
group can contain up to six cards.  The first card is the GROUP SPECIFICATION
CARD and has the code GEN in the first  three columns.  The second card contains
the name of the chemical being simulated.  Card three contains a number of
variables that enable the user to select the model options.  A schematic showing
key options pertaining to the Saturated Zone Module is indicated in Figure A.3.
If transport in a stream  (Surface Water Module)  is simulated, the variable XST is
the fourth card and indicates the distance from the point of groundwater plume
interception to the water supply intake.  The next card, i.e. values of TPSTN(I),
is necessary only if the Saturated Zone Module is run in the unsteady state and
contains the time values at which the saturated zone results are to be computed.
The final card is the END CARD that indicates the termination of this set of
data.  Table A-8 is an example of a typical General Data Group.

A.5.2  Source Data Group

The contents and format for the Source  Data Group are shown in Table A-9.  This
group describes the contaminant source-specific data.  The first card is the
                                       159

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Table A-6.  CONTENTS AND  FORMAT  OF  A TYPICAL EMPIRICAL DISTRIBUTION SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card     Contents                                   Format
El

E2

E3

E4

E5

Note:
 'BMP
ICOUNT
         "BMP"

         I, ICOUNT

         EMPPRM(J,2,I), J=  1,1COUNT

         EMPPRM(J,1,I), J=  1,1COUNT

         "END"
A3

2110

10(F8.0, 2X)

10(F8.0, 2X)

A3
         Card/lines E3  and  E4  are  repeated twice if more than 10 coordinates are
         input.  Card/lines E2,  E3,  and E4 are repeated if more than one variable
         has an empirical distribution.
                              Definition of Contents
               Subgroup  Specification Card indicating the start of the Empirical
               Distribution  Subgroup.

               Integer which identifies the variable being input.  See the
               individual  data  group tables for the values of I for specific
               variables.  Note that I is not a counter.

               Number of coordinates of the empirical cumulative frequency
               distribution.
EMPPRM(J,2,I)  Cumulative probability (coordinate)  values for the empirical
               distribution  for  variable I.

EMPPRM(J,1,I)  Corresponding variable values associated with the above
               probabilities.
"END"
               End Card  indicating the end of the Empirical Distribution
         Subgroup .
                                        160

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Table A-7.  CONTENTS AND  FORMAT  OF THE GENERAL DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card     Contents                                   Format
Gl

G2

G3





G4

G5

G6
"GEN"

CHEMICAL

OPTION, ISOURC, OPTAIR,
RUN, MONTE, ROUTE, ISTEAD,
NT, IOPEN, IYCHK, IZCHK
PALPH, LANDF, APPTYP,  COMPLETE

XST

TPSTN(I),  1=1, NT

"END"
                                     A3

                                     80A1

                                     315, 5X,  A13, 2X,
                                     715, F5.0,  315
                                     F10 . 0

                                     10(F8.0,  2X)

                                     A3
                              Definition of Contents
"GEN"



CHEMICAL

OPTION
ISOURC
OPTAIR
         0
         1
         2

RUN
DETERMINISTIC
MONTE

MONTE
Group Specification  Card  indicating the start of the General Data
Group.

Name of chemical being  simulated.

Integers defining which scenario to run.
Saturated Zone Transport  Module  only
Unsaturated and Saturated Zone Modules
Unsaturated, Saturated  and Surface Water Modules
Saturated Zone and Surface Water Modules
Air Modules only

Flag indicating the  type  of saturated zone boundary condition.
Gaussian source
Patch source

Flag indication which air modules to run.
No air modules are run
Air Emissions Module run
Air Emissions and Air Dispersion Modules run

Flag indicating the  type  of run.
The number of Monte  Carlo  simulations to be performed.
                                        161

-------
Table A-7.  CONTENTS AND FORMAT OF THE GENERAL DATA GROUP  (continued)
4444444444444444444444444444444444444444444444444444444444444444444
                              Definition of Contents
ROUTE          Flag indicating the exposure route  for  the  Surface  Water  Module.
               (This parameter is ignored  if not running the  Surface  Water
               Module. )
         1     Human exposure through drinking water
         2     Human exposure through fish consumption
         3     Exposure to aquatic organisms

ISTEAD         Flag indicating unsteady- or steady-state simulation of the
               unsaturated and saturated zone transport.
         0     Unsteady-state
         1     Steady-state

NT             Number of time steps for which unsteady-state  saturated zone
               transport results are required.

IOPEN          Integer flag indicating the information to  be  output.
         0     Opens all *.VAR and *.OUT files
         1     Opens only the main output  file, STATS. OUT,  and  SAT1.0UT
         2     Opens only the main output  file and STATS. OUT

XST            Instream distance between the point of  groundwater  loading to  the
               downstream water supply intake.  Include only  when  running the
               Surface Water Module.

TPSTN(I)       Times at which unsteady-state transport results  for the saturated
               zone are required  (Needed only when ISTEAD  = 0) .

IYCHK          Flag for rejecting well locations outside of the groundwater plume
               width when in Monte Carlo mode.
         0     Rejects the generated receptor well location y-coordinate value
         1     Does not reject the generated y-coordinate  value

IZCHK          Flag for rejecting well locations outside of the groundwater plume
               depth when in Monte Carlo mode.
         0     Rejects the generated receptor well location z-coordinate value
         1     Does not reject the generated z-coordinate  value

PALPH          The selected confidence level, in percent,  for the  four estimated
               percentiles  (80th, 85th, 90th, 95th) .

LANDF          Flag for running the Landfill Module.
         0     Do not run the Landfill Module
         1     Run the Landfill Module
                                       162

-------
Table A-7.  CONTENTS AND FORMAT OF THE GENERAL DATA GROUP  (concluded)
4444444444444444444444444444444444444444444444444444444444444444444
                              Definition of Contents
APPTYP         Flag for the type of application being  simulated.
         1     Generic MULTIMED application
         2     Subtitle D MULTIMED application

COMPLETE       Flag indicating whether all the necessary  input parameters  have
               been defined  (parameter used  in the preprocessor) .
         0     Undefined parameters exist in the  input
         1     No undefined parameters exist in the  input

"END"          End Card indicating the end of the General Data Subgroup.
GROUP SPECIFICATION CARD, with the code SOU in the  first three  columns.   This  is
followed by the Array Subgroup, which is indicated  by the SUBGROUP  SPECIFICATION
CARD with the code ARR in the first three columns.  Details of  the  Array  Subgroup
were presented in Table A-5 and Section A. 4. 4.  This subgroup contains  an array
of information about the values and/or the distributions and lower  and  upper
bounds of (up to) nine source-specific variables.   The variables  associated with
each index I are listed in Table A-10.

If any of the variables are specified to have an empirical distribution
(NDSTPRM(I)  = 6), then it is necessary to include the Empirical Distribution
Subgroup discussed in Section A. 4. 5.  If none of the source-specific variables
have an empirical distribution, this subgroup is not necessary.

Of the nine variables included in this group, three can be derived.  These are
the spread of input source, the length scale, and the width scale of the
facility. Thus, NDSTPRM(4), NDSTPRM(S), and NDSTPRM(9) can have values  less than
zero (see Table A-4) .   The methods used to derive these variables are discussed
in Section 5.5.1 of Salhotra et al .  (1990) or Section 6.2 of this manual.

Note that if the user specifies LANDF=1 in the General Data Group (i.e.,  uses  the
Landfill Module to compute infiltration) the value  of infiltration  specified  in
the Source Data Group (Table A-10) is ignored.

An END CARD indicates the end of the Source Data Group.

A. 5. 3  Landfill Data Group

This group contains data required by the Landfill Module and consists of  four
subgroups.  It is required only if the infiltration is not input  by the user  in
the Source Data Group.  The subgroups and the associated codes  are  listed below:
                                       163

-------
Figure A.3
                                        164

-------
TABLE A-8.   EXAMPLE OF A TYPICAL GENERAL  DATA GROUP
    GENERAL  DATA

    ***   CHEMICAL NAME FORMAT(80A1)
    DEFAULT  CHEMICAL

    ***    ISOURC                              ROUTE      NT        IYCHK   PALPH      APPTYP
    ***OPTION   OPTAIR  RUN               MONTE    ISTEAD      IOPEN     IZCHK     LANDF    COMPLETE
         300     DETERMINISTIC     500    1    1     1     0     0    190.0    1     1    0


    ***XST
       1000.00

    END  GENERAL
                                                                              165

-------
Table A-9.  CONTENTS AND FORMAT OF THE SOURCE-SPECIFIC  DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444444444444
Card                 Contents                                  Format
SI

A1-A3

E1-E5

S2
                     "SOU"

                     Array Subgroup

                     Empirical Distribution Subgroup

                     "END"
                                                               A3

                                                               (See Table A- 5)

                                                               (See Table A-6)

                                                               A3
                     Definition of Contents
"SOU"

Array Subgroup

Empirical
Distribution
Subgroup

"END"
    Control Data
    Layer Thickness and
      Material Data
    Liner Property
      Data
    Landfill Material
      Property Data
    Hydrologic Data
                     Group Specification Card indicating the  start of  the  Source  Data  Group.

                     Subgroup defining the source variables.

                     Subgroup defining any empirical distributions.



                     End Card indicating the end of the Source Data Group.
                                                                        Refer  to  Table

                                                                        A-ll
                                                                        A- 12

                                                                        A- 13

                                                                        A- 15

                                                                        A-17
                                      Specification Code

                                      CON
                                      LAY

                                      LIN

                                      SAT

                                      HYD
The first card of this group is the GROUP SPECIFICATION  CARD  and includes  the code LFL in the first three columns.  The next card is the first subgroup
specification card and includes the appropriate  code  shown  above.   Data  for each of the subgroups of the Landfill Module are described below.  None of the
variables in this group can be derived  (i.e.,  they  cannot have  a distribution type of -1) .

Note that some of the input units for the Landfill  Module are non-metric.   These data are automatically converted from the input units to the metric
system of units by the code before computations  are performed.
                                                                            166

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TABLE A-10.  VARIABLES IN THE SOURCE-SPECIFIC ARRAY SUBGROUP
    SOURCE  SPECIFIC VARIABLE DATA
    ARRAY VALUES
    ***         SOURCE SPECIFIC VARIABLES
*** VARIABLE NAME UNITS
***
1
2
3
4
5
6
7
8
9
Infiltration rate (m/yr)
Area of waste disp unit (mA2)
Duration of pulse (yr)
Spread of contaminant srce (m)
Recharge rate (m/yr)
Source decay constant (1/yr)
Init cone at landfill (mg/1)
Length scale of facility (m)
Width scale of facility (m)
DISTRIBUTION PARAMETERS
MEAN STD
0
0
0
-1
0
0
0
-1
-1
-999.
-999.
-999.
-999.
-999.
-999.
1.00
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
DEV MIN
0.100E-
0.100E-
0.100E-
0.100E-
0.100E-
O.OOOE+
O.OOOE+
0.100E-
0.100E-
LIMITS
MAX
09
01
08
08
09
00
00
08
08
0
-
-
0
0
-
-
0
0
.100E+11
999.
999.
.100E+11
.100E+11
999.
999.
.100E+11
.100E+11
END ARRAY
    END SOURCE  SPECIFIC VARIABLE DATA
                                                                              167

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A.5.3.1  Landfill Control Data Subgroup--

Table A-ll describes the landfill control subgroup and the default values.  Data
in the other subgroups vary depending on the values specified in this subgroup.

A.5.3.2  Layer Thickness and Material Data Subgroup--

Table A-12 describes the layer thickness and material data necessary for the
Landfill Module.  The data consist of the layer thickness and the material number
associated with each layer.  The material numbers correspond to the order in
which the material properties are read in as part of the Material Properties
Subgroup described in Section A.5.3.4.

A.5.3.3  Liner Property Data Subgroup--

Liners are low permeability sheets of rubber or plastic materials which are used
as barriers to vertical flow.  A description of the liner property data can be
found in Table A-13.  There should be one set of data for each liner (LFCP(4)) in
Table A-ll.  These data include the liner thickness, liner hydraulic
conductivity,  percent failure of the liner and the layer number containing the
liner.  The variables in this subgroup are presented in Table A-14.

A.5.3.4  Landfill Material Property Data Subgroup--

The landfill can consist of a number of different materials  (the number specified
by the value of LFCP(2) in Table A-ll) with different hydrogeological properties.
The properties for each of the materials are included in this subgroup.  Details
of the contents and formats of this subgroup are shown in Tables A-15 and A-16.
When the landfill consists of more than one material, information about each
material is input using an Array Subgroup.  These materials are subsequently
identified by the order in which the Array Subgroups appear.  Thus, material
number 4 would refer to the material that has properties included in the fourth
Array Subgroup.  The termination of data for each material is indicated by an END
CARD.  The end of the Landfill Material Property Data Subgroup is also indicated
by an END CARD.

A.5.3.5  Hydrologic Data Subgroup--

A water balance approach is used to estimate the average infiltration rate over
the duration of an "event."  An event is defined as the typical period between
the start of two sequential storms, and includes both the storm duration and the
inter-storm interval.  Table A-17 describes the contents and format of the
Hydrologic Data Subgroup required to perform this balance.  The hydrologic
parameters are presented in Table A-18.

A.5.4  Chemical Data Group

The contents and format of the Chemical Data Group are shown in Table A-19.  The
first card is the GROUP SPECIFICATION CARD, with the code CHE in the first three
columns.  The second card is the SUBGROUP SPECIFICATION CARD, with the code ARR
in the first three columns.  This subgroup contains the array of information
                                       168

-------
Table A-ll.  CONTENTS AND FORMAT OF  THE  LANDFILL MODULE CONTROL DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format
VI

C02

C03

C04
"LFL"


CON


CURVE

LFCP(l)

LFCP(2)

LFCP(3)




LFCP(4)

LFCP(5)

LFCP(6)



LFCP(7)
"END
               "LFL"

               "CON"

               CURVE, LFCP(I),1

               "END"
= 1,6
A3

A3

F10.0, 6110

A3
               Definition of  Contents
               Group Specification  Card  indicating the start of the Landfill
               Module Data Group.

               Subgroup Specification  Card indication the start of the Landfill
               Module Control Data  Subgroup.

               SCS curve number  for moisture  condition AMC-II.

               Number of layers  in  the Landfill  Module.

               Number of different  porous  materials.  Maximum permissible is 20.

               Parameter indicating the  type  of  relationship used for relative
               permeability versus  saturation.
         1     van Genuchten functional  parameters
         2     Brooks and Corey  functional parameter

               Number of liners  in  the landfill.

               Number of seasons.

               Parameter indicating method for calculating evapotranspiration.
               (Only one option  is  available  in  the current version of the code.)
         0     Seasonal potential evapotranspiration  read in

               Number of the layer  which is the  lateral  drainage layer.   Enter 0
               if there is no lateral  drainage layer.

               End Card indicating  the end of the Landfill Module Control Data
               Subgroup .
                                        169

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Table A- 12.  CONTENTS AND FORMAT OF THE LANDFILL MODULE  LAYER  THICKNESS  AND
             MATERIAL DATA SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
LAI            "LAY"                                      A3

LA2            LFLAYR(I), LPROP(I)                        G10.0,  110

LA3            " END "                                      A3

Note:    Card/line LA2 is repeated  for  each  layer  in  the  Landfill  Module (LFCP(l)
         in Table A-ll) .
               Definition of Contents
"LAY"          Subgroup Specification Card  indicating  the  start  of  the Landfill
               Layer Thickness and Material  Subgroup.

LFLAYR(I)      Thickness of layer I.

LPROP(I)       Material number for layer  I  corresponding to  data read as part of
               the Material Properties  Subgroup  (see Section A. 5. 3. 4).

"END"          End Card indicating the  end  of  this  subgroup.
about the values and/or the distributions and upper  and  lower  bounds  of up to 16
chemical-specific variables.  The variables being  input  are  identified by the
value of the index I.  The variables associated with each  index  I  are shown in
Table A-20.  For example, a data card with 1=6 indicates that  the  card contains
information about the base catalyzed hydrolysis rate constant  for  the chemical
being simulated.

If any of the variables are specified to have an empirical distribution
(NDSTPRM(I) = 6), then it is necessary to include  the empirical  distribution
subgroup, discussed in Section A. 4. 5.  If none of  the chemical-specific variables
have an empirical distribution, then this subgroup is not  necessary.

A. 5. 5  Unsaturated Zone Flow Data Group

This group contains data required by the Unsaturated Zone  Flow Module and
consists of five subgroups.  The Control Data Subgroup should  be the  first
subgroup in the Unsaturated Zone Flow Data Group.  The subgroups and  the
associated codes are listed below:
                                        170

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Table A- 13.  CONTENTS AND  FORMAT  OF  THE  LANDFILL MODULE LINER PROPERTY
             SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
A3

A3

15

A3

(See Table A-5)

(See Table A-6)

A3

A3
LI

LAI

LA2

LA3

A1-A3

E1-E5

LI2

LI 3

Note:
"LIN"
"LAY"
                "LIN"

                "LAY"

                LINER (I)

                " END "

                Array Subgroup

                Empirical Distribution  Subgroup

                "END"  (Material)

                "END"
         Cards/lines A1-A3  and  E1-E5  need to be repeated for each liner  (i.e.,
         LFCP(4) number of  times).  The  Empirical  Distribution Subgroup is needed
         only if one or more variables  in the Array Subgroup has an empirical
         distribution.
                              Definition of Contents
               Subgroup Specification  Card indicating the start of the Landfill
               Liner Properties  Data Subgroup.

               Subgroup Specification  Card indicating data containing layer
               number associated with  liner properties.
LINER (I)       Layer number  associated with the following data.

Array Subgroup Subgroup defining  the  landfill  liner properties variables.

Empirical      Subgroup defining  any  empirical distributions.
Distribution
Subgroup
"END"
"END"
               End Card  indicating  the  end of data for a liner (one such end card
               is required  for  each liner) .

               End Card  indicating  the  end of this subgroup.
                                        171

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TABLE A-14.  VARIABLES IN THE LANDFILL  LINER  PROPERTY ARRAY SUBGROUP
    ARRAY VALUES
    ***         LANDFILL  LINER  VARIABLES
                   VARIABLE  NAME
                                                 UNITS
                                                                     DISTRIBUTION
                                                                                    PARAMETERS
                                                                                   MEAN      STD DEV
                          LIMITS
                       MIN      MAX
     1 Thickness of  liner  (mills)
     2 Hydraulic conductivity  (cm/hr)
     3 Failure rate  of  liner  (%)
    END ARRAY
-999.
-999.
-999.
-999.
-999.
-999.
0.100E-08 -999.
0.100      10.0
O.OOOE+00  100.
    END LINER  1
    END LINER DATA
                                                                            172

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Table A- 15.  CONTENTS AND  FORMAT  OF  THE  LANDFILL MODULE MATERIAL PROPERTY
             SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
A3

(See Table A-5)

(See Table A-6)

A3

A3
SA1

A1-A3

E1-E5

SA2

SA3

Note:
                "SAT"

               Array Subgroup

               Empirical Distribution Subgroup

                "END"  (Material)

                "END"
         Cards/lines A1-A3  and  E1-E5  need to be repeated for each material  (i.e.,
         LFCP(2) number of  times).  The Empirical Distribution Subgroup is needed
         only if one or more  variables  in the Array Subgroup has an empirical
         distribution.
""
"SAT
Array Subgroup

Empirical
Distribution
Subgroup
"END
"END"
                              Definition of Contents
                     Subgroup  Specification Card indicating the start of the
                     Landfill  Material  Data Subgroup.

                     Subgroup  defining  the landfill material variables.

                     Subgroup  defining  any empirical distributions.
                     End  Card  indicating the end of data for a material  (one such
                     end  card  is  required for each material) .

                     End  Card  indicating the end of this subgroup.
                                        173

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TABLE A-16.  VARIABLES IN THE LANDFILL  MATERIAL PROPERTY ARRAY  SUBGROUP
    SATURATED MATERIAL PROPERTY  PARAMETERS FOR LANDFILL
    ARRAY VALUES
    ***       LANDFILL MATERIAL VARIABLES
*** VARIABLE NAME UNITS
***
1
2
3
4
5
Sat hydraulic conduct (cm/hr)
Porosity
Residual water content
Brooks and Corey exponent
ALFA coeff for landfill (I/cm)
6 BETA - Van Genuchten exponent
END ARRAY
DISTRIBUTION PARAMETERS LIMITS
MEAN STD DEV MIN MAX
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
-999.
-999.
-999.
-999.
-999.
-999.
0.100E-10
0.100E-08
0.100E-08
O.OOOE+00
O.OOOE+00
O.OOOE+00
0.100E+05
1.00
1.00
10.0
1.00
10.0
    END MATERIAL  1
    END SATURATED MATERIAL PROPERTY  DATA
                                                                              174

-------
Table A- 17.  CONTENTS AND FORMAT OF  THE  LANDFILL MODULE HYDROLOGY SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card         Contents                                  Format
HY           "HYD"                                      A3

A1-A3        Array  Subgroup                            (See Table A- 5)

E1-E5        Empirical Distribution Subgroup           (See Table A-6)

HY2          "END"  (Season)                             A3

HY3          "END"                                      A3

Note:        Cards/lines A1-A3 and E1-E5 need to be repeated for each season  (i.e.,  LFCP(5)  number of times) .   The Empirical Distribution Subgroup is
             needed only if one or more variables in the Array Subgroup has an  empirical  distribution.
                              Definition of Contents
"HYD"                         Subgroup Specification Card indicating the start of the Landfill Hydrology Data  Subgroup.

Array Subgroup                Subgroup defining the landfill hydrology variables.

Empirical                     Subgroup defining any empirical distributions.
Distribution
Subgroup

"END"                         End Card indicating the end of data for a season (one such end card  is required  for  each season) .

"END"                         End Card indicating the end of this subgroup.
                                                                            175

-------
TABLE A-18.  VARIABLES  IN THE  LANDFILL HYDROLOGY ARRAY SUBGROUP
    HYDROLOGY  PARAMETERS
    ARRAY VALUES
    ***               HYDROLOGY VARIABLES
    ***
    ***
                   VARIABLE  NAME
                                                 UNITS
                                                                     DISTRIBUTION
   PARAMETERS
  MEAN      STD DEV
                LIMITS
             MIN      MAX
     1 Precipitation  (cm)
     2 Duration of  event  (days)
     3 Pan evaporation  (cm)
    END ARRAY
-999.
-999.
-999.
-999.
-999.
-999.
O.OOOE+00 -999.
O.OOOE+00 -999.
O.OOOE+00 -999.
    END SEASON   1
    END HYDROLOGY DATA
                                                                             176

-------
Table A- 19.  CONTENTS AND FORMAT OF THE  CHEMICAL -SPECIFIC DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
Cl             "CHE"                                      A3

A1-A3          Array Subgroup                             (See Table A-5)

E1-E5          Empirical Distribution  Subgroup            (See Table A-6)

C2             "END"                                      A3
                     Definition of  Contents
"CHE"                Group Specification  Card  indicating the start of the
                     Chemical Data Group.

Array Subgroup       Subgroup defining  the  chemical  variables.

Empirical            Subgroup defining  any  empirical distributions.
Distribution
Subgroup

"END"                End Card indicating  the end of  the Chemical Data Group.
   Subgroup                Specification  Code       Refer to Table

   Control Data            CON                      A-21
   Layer Thickness and     MAT                      A-22
     Material Data
   Unsaturated Material    SAT                      A-23
     Property Data
   Soil Moisture Data      SOI                      A-25

The first card of this group  is the GROUP SPECIFICATION  CARD and includes the
code VFL in the first three columns.  The next  card is the first subgroup
specification card.  Data  for each of these  subgroups are described below.   The
end of this group is indicated by an END  CARD.

A. 5. 5.1  Unsaturated Zone  Flow Control Data  Subgroup- -

Table A-21 describes the Unsaturated Zone Flow  Control Data Subgroup parameters.
Data in the other subgroups vary depending on the  options specified in the
Control Data Subgroup.  The termination of this subgroup is indicated by the END
CARD.
                                        177

-------
TABLE A-20.  VARIABLES IN THE CHEMICAL ARRAY SUBGROUP
    CHEMICAL  SPECIFIC VARIABLE DATA
    ARRAY VALUES
    ***       CHEMICAL SPECIFIC VARIABLES
*** VARIABLE NAME UNITS
***
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Solid phase decay coeff (1/yr)
Diss phase decay coeff (1/yr)
Overall chem dcy coeff (1/yr)
Acid cataly hydrol rte(l/M-yr)
Neutral hydrol rate cons (1/yr)
Base cataly hydrol rte(l/M-yr)
Reference temperature (C)
Normalized distrib coeff (ml/g)
Distribution coefficient
Biodegrad coef (sat zone) (1/yr)
Air diffusion coeff (cm2/s)
Ref temp for air diffusion (C)
Molecular weight (g/mole)
Mole fraction of solute
Solute vapor pressure (mm Hg)
Henry^s law cons (atm-mA3/M)
Not in use
Not in use
Not in use
DISTRIBUTION PARAMETERS LIMITS
MEAN STD DEV MIN MAX
-1 -999.
-1 -999.
-1 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
-2 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
0 -999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
O.OOOE+00
0.100E-08
O.OOOE+00
0.100E-09
O.OOOE+00
O.OOOE+00
O.OOOE+00
0.100E+11
0.100E+11
0.100E+11
-999.
-999.
-999.
100.
-999.
0.100E+11
-999.
10.0
100.
-999.
1.00
100.
1.00
1.00
1.00
1.00
END ARRAY
    END CHEMICAL SPECIFIC VARIABLE DATA
                                                                              178

-------
Table A-21.  CONTENTS AND FORMAT OF  THE  UNSATURATED ZONE FLOW MODULE CONTROL
             DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card     Contents                             Format
VI

C02

C03

C04
"VFL"

"CON"

VFCP (I) ,  I

"END"
                    = 1,
A3

A3

5110

A3
               Definition of  Contents
ITVFL
CON
VFCP(l)
VFCP(2;
VFCP(3;
VFCP(4;
VFCP(Si
 'END
      Group Specification Card  indicating  the  start  of the Unsaturated
            Zone Flow Module Data  Group.

      Subgroup Specification Card  indicating the  start of the
      Unsaturated Zone Flow Module Control Data Subgroup.

      Number of nodes in the Unsaturated Zone  Flow Module.  The value of
      this parameter is currently  generated in the code.   Thus, the
      value in the input file is ignored.

      Number of different porous materials up  to  a maximum of 20.   If
      the depth of the unsaturated zone is randomly  generated in Monte
      Carlo mode, VFCP(2) must  equal  1.

      Parameter indicating the  type of relationship  of relative
      permeability versus saturation.
      van Genuchten functional  parameters
      Brooks and Corey functional  parameter

      Parameter indicating the  method of generating  vertical
      discretization when the depth of the unsaturated zone is constant.
      This parameter is ignored in the current version of the code.

      Number of layers in the unsaturated  flow system (up to a maximum
      of 20) .   If the depth of  the unsaturated zone  is randomly
      generated in Monte Carlo  mode,  VFCP(5) must equal 1.)

      End Card indicating the end  of  this  subgroup.
                                        179

-------
Note that in Monte Carlo mode, the total depth of the unsaturated zone can be
randomly generated by setting VFCP(2)  and VFCP(5) to a value of one.  VTCP(l) in
Table A-27 must also be set to a value of one.  In other words, only one
homogeneous layer can have a Monte Carlo distribution associated with it.

A.5.5.2  Unsaturated Flow Module Layer Thickness and Material Data Subgroup--

Table A-22 describes the layer thickness and material data necessary for the
Unsaturated Zone Flow Module.  The data consist of the layer thickness and the
material number associated with each layer.  When only one layer is simulated,
the layer thickness is equal to the total depth of the unsaturated zone and this
parameter can have a Monte Carlo distribution assigned to it.  The material
numbers correspond to the material properties which are read in using the
Material Properties Subgroup described in Section A.5.5.3.

A.5.5.3  Unsaturated Zone Flow Material Property Subgroup--

The unsaturated zone can consist of a number of different materials (the number
specified by the value of VFCP(2)  in Table A-21) with different hydrogeological
properties.  The properties for each of the materials are input using the Array
and Empirical Subgroups in the Unsaturated Zone Material Property Subgroup, which
is identified by the code SAT.  Details of the contents and format of this
subgroup are shown in Table A-23.   The variables included in this subgroup are
shown in Table A-24.  Note that none of these variables can be derived (i.e.,
none have a distribution type of -1).

When the unsaturated zone consists of more than one material, information about
each material is input using an Array Subgroup.  These materials are subsequently
identified by the order in which the Array Subgroups appear.  Thus, the fourth
Array Subgroup  (after the Subgroup Specification Card) contains information about
the properties of material number 4.  The termination of data for each material
is indicated by an END CARD.  The end of the unsaturated materials data is also
indicated by an END CARD.

A.5.5.4  Unsaturated Zone Flow Moisture Data Subgroup--

In order to solve the unsaturated zone flow problem, both the relationship
between the relative permeability and water content and the relationship between
pressure head and water content need to be specified for each material (refer to
Section 3 of Salhotra et al.  (1990)).   The information needed to describe these
relationships is provided in the Unsaturated Zone Moisture Data Subgroup,
identified by the code SOI.  The contents and format of this subgroup are
described in Table A-25.

The van Genuchten parameters, alpha and beta, are required by the code to
calculate the pressure head versus water content curve.  The same parameters can
be used to describe the relationship between relative permeability and water
content by setting VFCP(3) equal to one in Table A-21.  However, the code
contains the option of using the Brooks and Corey relationship instead (VFCP(3)
                                       180

-------
Table A-22.     CONTENTS  AND FORMAT OF THE UNSATURATED  FLOW  MODULE LAYER THICKNESS
                AND  MATERIAL DATA SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card     Contents                                   Format
Ml        "MAT"                                      A3

M2       VFLAYR(I),  I PROP (I)                        G10.0,  110

M3        "END"                                      A3

Note:    Card/line  M2  is  repeated for each layer in the Unsaturated Flow Module
          (VFCP(5) in Table  A-21) .
                              Definition  of Contents
"MAT"                 Subgroup Specification Card  indicating  the start of the
                      Unsaturated Flow Module Layer Thickness and Material
                      Subgroup .

VFLAYR(I)             Thickness  of layer I.

IPROP(I)              Material number for layer I  corresponding to data read as
                      part  of the Material Data Subgroup  (see Section A. 5. 5. 3).
 END"                 End Card indicating the end of this  subgroup.
                                        181

-------
Table A-23.  CONTENTS AND  FORMAT  OF  THE  UNSATURATED ZONE FLOW MODULE MATERIAL
             PROPERTY SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
SA1             "SAT"                                      A3

A1-A3          Array Subgroup                             (See Table A-5)

E1-E5          Empirical Distribution  Subgroup           (See Table A-6)

SA2             "END"  (Material)                           A3

SA3             "END"                                      A3

Note:    Cards/lines A1-A3  and  E1-E5 need to be repeated for each material.
                     )))))))))))))))))))))))))))
                     Definition of  Contents
"SAT"                Group  Specification Card indicating the start of the
                     Unsaturated  Zone  Flow Module Material Subgroup.

Array Subgroup       Subgroup  defining the material property variables.

Empirical            Subgroup  defining any empirical distributions.
Distribution
Subgroup

"END"                End Card  indicating the end of data for a material  (one such
                     end card  is  required for each material) .

"END"                End Card  indicating the end of this subgroup.
equal to 2 in Table A-21) .   If  the  Brooks  and Corey option is selected, the
exponent, n, must be specified  in addition to the van Genuchten parameters.

The subgroup specification  card is  followed by VFCP(2)  number of the Array
Subgroups, one subgroup  for each material.   Table A-26  presents the definitions
of the variables included in the Array  Subgroup.   None  of the variables in this
group can be derived  (i.e.,  none have a distribution type of -1).

Note that the data for each material are read in  the same sequence as in Table A-
23.  After the data for  each material has  been input,  an END card is inserted.
Finally, the end of the  subgroup is also indicated by an END CARD.
                                        182

-------
TABLE A-24.  VARIABLES IN THE UNSATURATED  FLOW  MATERIAL PROPERTY ARRAY SUBGROUP
    SATURATED MATERIAL  PROPERTY  PARAMETERS
    ARRAY VALUES
    ***   SATURATED MATERIAL   VARIABLES
                   VARIABLE  NAME
                                                 UNITS
                                                                     DISTRIBUTION
                                                                                    PARAMETERS
                                                                                   MEAN      STD DEV
                                 LIMITS
                              MIN      MAX
     1 Sat hydraulic conduct  (cm/hr)
     2 Unsaturated  zone porosity
     3 Air entry pressure  head  (m)
     4 Depth of the unsat  zone  (m)
    END ARRAY
0      -999.     -999.     0.100E-10 0.100E+05
0      -999.     -999.     0.100E-08 0.990
0      -999.     -999.     O.OOOE+00 -999.
0      -999.     -999.     0.100E-08 -999.
    END MATERIAL   1
    END
                                                                            183

-------
Table A-25.  CONTENTS AND FORMAT  OF  THE  UNSATURATED ZONE FLOW MODULE MOISTURE
             DATA SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format
SI1            "SOI"                                A3

A1-A3          Array Subgroup                       (See Table A-5)

SI2            "END"  (material)                     A3

SI3            "END"                                A3

Note:    Card/line A1-A3 need  to  be  repeated for each material.
                     )))))))))))))))))))))))))))
                     Definition of Contents
"SOI"                Group  Specification  Card indicating the start of the
                     Unsaturated  Zone  Flow Module Moisture Data Subgroup.

Array Subgroup       Subgroup  defining the moisture-related variables.

"END"                End Card  indicating  the end of data for a material  (one such
                     end card  is  required for each material) .

"END"                End Card  indicating  the end of this subgroup.
A. 5. 6  Unsaturated Zone Transport  Data  Group

The data required for the Unsaturated Zone  Transport Module are divided into two
subgroups.  Each subgroup is handled in the same manner as was described for the
subgroups of the Unsaturated Zone  Flow  Data Group.   The subgroups included in the
Unsaturated Zone Transport Data  Group are:

   Subgroup                Specification Code      Refer to Table

   Control Data            CON                      A-27
   Transport Properties    TRA                      A-28

The first card of this group is  the GROUP SPECIFICATION CARD and includes the
code VTL in the first three columns.  The next  card is the first SUBGROUP
SPECIFICATION CARD.  The contents  and format of each of these subgroups are
described below.  The termination  of the Unsaturated Zone Data Group is indicated
by an END CARD.
                                        184

-------
TABLE A-26.  VARIABLES IN THE UNSATURATED FLOW MOISTURE DATA ARRAY  SUBGROUP
    SOIL MOISTURE PARAMETERS
    ***   FUNCTIONAL COEFFICIENTS
    ARRAY VALUES
    ***   FUNCTIONAL COEFFICIE VARIABLES
    ***
    ***
                   VARIABLE NAME
                                                 UNITS
                                                                     DISTRIBUTION
   PARAMETERS
  MEAN      STD DEV
                LIMITS
             MIN      MAX
     1 Residual water content
     2 Brooks and Corey exponent,  EN
     3 ALFA van Genuchten coefficient
     4 BETA Van Genuchten coefficient
    END ARRAY
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0.100E-08  1.00
O.OOOE+00  10.0
O.OOOE+00  1.00
 1.00      5.00
    END MATERIAL  1
    END
    END UNSATURATED FLOW
                                                                            185

-------
A.5.6.1  Unsaturated Zone Transport Control Data Subgroup--

The contents and format of the Control Data Subgroup are shown in Table A-27.
The Control Data Subgroup should be the first subgroup included in the
Unsaturated Zone Transport Group.  Note that VTCP(l), the number of layers, is
set equal to 1 if the depth of the unsaturated zone is generated from a Monte
Carlo distribution in the Unsaturated Zone Flow Module.  The end of this subgroup
data is indicated by an END CARD.

A.5.6.2  Unsaturated Zone Transport Properties Subgroup--

The contents and format of the Transport Properties subgroup are described in
Table A-28.  Following the SUBGROUP SPECIFICATION CARD is one or more Array
Subgroup that contains the values of the unsaturated zone transport variables.
An Array Subgroup is required for each material layer.  If any of the variables
are specified to have an empirical distribution, then it is necessary to include
the Empirical Distribution Subgroup (for details see Section A.4.5).  An END CARD
is used to indicate the end of data for each layer.

The multiple layers option is available only when the depth of the unsaturated
zone is constant (i.e., not a Monte Carlo variable) in the Unsaturated Zone Flow
Module.  In the event that there is more than one transport layer, the sum of the
individual layer thicknesses must equal the sum of the layer thicknesses
specified in the Unsaturated Zone Flow Module.  However, note that the number of
layers and the corresponding thicknesses can differ between the two modules.

The definitions of the specific variables that comprise this subgroup are shown
in Table A-29.  Of the five variables shown, only the longitudinal dispersivity
of the soil can be derived.  The method by which it is derived is discussed in
Section 4.4.3.1 of Salhotra et al. (1990).  An END CARD indicates the end of the
Transport Data Subgroup.

A.5.7  Aquifer Data Group

The contents and format of the Aquifer Data Group are shown in Table A-30.  The
first card is the GROUP SPECIFICATION CARD, with the code AQU included in the
first three columns.  Following this is an Array Subgroup, which contains
information about the values and/or distributions of up to 18 aquifer-specific
variables.  The variables included in this subgroup are shown in Table A-31.
With the exception of the source thickness, the variables are used only in the
Saturated Zone Transport Module.  The source thickness is used to satisfy the
mass balance between the Unsaturated Zone  (or the Source when the unsaturated
zone is not simulated) and the Saturated Zone Transport Modules.

Ten of the aquifer variables can be either derived or directly input.  These
variables are the particle diameter,  porosity, bulk density, source thickness,
hydraulic conductivity, seepage velocity, retardation coefficient, and the
longitudinal, lateral, and vertical dispersivities.  The available options and
the algorithms for each of them are explained in Section 5.5.3 of Salhotra et al.
(1990) .
                                       186

-------
Table A-27.  CONTENTS AND FORMAT OF THE UNSATURATED  ZONE  TRANSPORT MODULE
             CONTROL DATA SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
VI             "VTL"                                      A3

TCI            "CON"                                      A3

TC2            VTCP(I), I = 1,10                          10110

TC3            WTFUN                                      F10.0

TC4            "END"                                      A3
                     Definition of Contents
"VTL"          Group specification card  indicating  the  start  of  the Unsaturated
               Zone Transport Group.
"CON"          Control card indicating  the  start  of  the  Unsaturated Transport
               Control Subgroup.

VTCP(l)         Number of layers used to  simulate transport  in the unsaturated
               zone  (up to a maximum of 20).   Note that  the  number of layers
               specified in the Unsaturated Zone  Transport Module  can be
         different from the number of layers  specified  in the  Unsaturated
         Flow Module.  VTCP(l) must be  set  equal  to  one  if the depth of the
               unsaturated zone in the  Unsaturated Flow  Module is  to be randomly
               generated in Monte Carlo mode.

VTCP(2)        Number of time values at which concentration  in the unsaturated
               zone  is to be evaluated.   This variable,  which  corresponds to the
               number of control points in  the convolution integral for coupling
               the unsaturated and saturated  zones,  is not used when the model is
               run in steady-state.  In the current  version  of the preprocessor,
               this  value is set to 20.

VTCP(3)        Dummy integer.  Not used in  the current version of  the model.

VTCP(4)        Type  of scheme used to evaluate transport in  the unsaturated zone.
               Note  that the Stehfest algorithm is recommended when the ratio of
               layer thickness to longitudinal dispersivity  is less than 20.
         1     Stehfest numerical inversion algorithm
         2     Convolution integral approach

                                                                (continued)
                                        187

-------
Table A-27.  CONTENTS AND FORMAT OF THE UNSATURATED  ZONE  TRANSPORT  MODULE
             CONTROL DATA SUBGROUP  (concluded)
4444444444444444444444444444444444444444444444444444444444444444444
                              Definition of Contents
P(5)           For VTCP(4) = 1, the number  of  terms  governing  the  accuracy of the
               Stehfest algorithm.  It must be a  positive  even integer.  A value
               of 18 is suggested as an  initial trial  value.

               For VTCP(4) = 2, the number  of  increments used  in the temporal
               discretization of convolution integral  approach (a  value  of 10 is
               recommended) .

VTCP(6)        Number of points in the Lagrangian scheme used  for  interpolating
               concentration values  (a value of 3 is recommended) .

VTCP(7)        Number of Gauss points used  in  Gauss-Legendre numerical
               integration of the convolution  values (a value  of 104 is
               recommended) .

VTCP(8)        Number of segments for the numerical  approximation  of the
               convolution integral  (a value of 2 is recommended) .

VTCP(9)        Type of source boundary condition.  In  the  current  version of the
               code, the value of this parameter  is  automatically  set in
               subroutine DEFAULTS . FOR,  based  on  the values of other input
               parameters .

VTCP(IO)       Parameter indicating if time values for computing concentration in
               the unsaturated zone are  to  be  generated.   This variable  is not
               used when the model is run in steady-state.  It is  automatically
               set to 1  (i.e., yes), the recommended value, in the current
               version of the preprocessor.

WTFUN          Value of weighting factor used  to  generate  time step values for
               evaluating concentration  in  the unsaturated zone.   This variable,
               which is not used when the model is run in  steady-state,  is
               automatically set to 1.2  in  the current version of  the
         preprocessor.

"END"          End Card indicating the end  of  this data subgroup.
                                        188

-------
Table A-28.  CONTENTS AND FORMAT  OF  THE  UNSATURATED ZONE TRANSPORT MODULE
             PROPERTIES SUBGROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
Tl             "TRA"                                      A3

A1-A3          Array Subgroup                             (See Table A-5)

E1-E5          Empirical Distribution  Subgroup           (See Table A-6)

T2             "END"  (Layer)                              A3

SA3            "END"                                      A3

Note:    Cards/lines A1-A3  and  E1-E5 need to be repeated for each layer.
                     )))))))))))))))))))))))))))
                     Definition of  Contents
"TRA"                Group  Specification  Card indicating the start of the
                     Unsaturated  Zone  Transport Module Data Subgroup.

Array Subgroup       Subgroup  defining the  transport variables.

Empirical            Subgroup  defining any  empirical distributions.
Distribution
Subgroup

"END"                End Card  indicating  the end of data for a layer (one such
                     end card  is  required for each layer) .

"END"                End Card  indicating  the end of this subgroup.
If any of the variables  in  this  group  are  assigned an empirical distribution
(NDSTPRM(I) = 6), then it is necessary to  include the Empirical Distribution
Subgroup  (see Section A. 4. 5) .  END  CARDS are  required to indicate the termination
of both the Array and the Empirical  Subgroups.   A final END CARD indicates the
end of the Aquifer Data  Group.

A. 5. 8  Surface Water Data Group

The contents and format  of  the Surface Water  Data Group are shown in Table A-32.
The first card is the GROUP SPECIFICATION  CARD  with the code SUR in the
first three columns.  This  is followed an  Array Subgroup that contains
information about the values/distributions of 13 variables, two of which are not
used in the current version of the  model  (see Table A-33) .   If any of these
                                        189

-------
TABLE A-29.  VARIABLES IN THE UNSATURATED  TRANSPORT PROPERTIES ARRAY SUBGROUP
    TRANSPORT PARAMETER
    ARRAY VALUES
    ***   UNSATURATED TRANSPOR  VARIABLES
    ***
    ***
                   VARIABLE  NAME
                                                 UNITS
                                                                     DISTRIBUTION
           PARAMETERS
          MEAN      STD DEV
                          LIMITS
                       MIN      MAX
     1 Thickness of  layer  (m)
     2 Longit disper of  layer  (m)
     3 Percent organic matter
     4 Bulk dens of  soil layer  (g/cc)
     5 Biological decay  coeff  (1/yr)
    END ARRAY
 0
-1
 0
 0
 0
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0.100E-08 -999.
O.OOOE+00 0.100E+05
O.OOOE+00
0.100E-01
                            O.OOOE+00
 100.
 5.00
-999.
    END LAYER  1
    END UNSATURATED TRANSPORT  PARAMETERS
    END TRANSPORT MODEL
                                                                            190

-------
Table A-30.  CONTENTS AND FORMAT OF THE AQUIFER-SPECIFIC  DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format
Ql             "AQU"                               A3

A1-A3          Array Subgroup                       (See  Table  A-5)

E1-E5          Empirical Distribution Subgroup      (See  Table  A-6)

Q2             "END"                               A3
                              Definition of Contents
"AQU"                Group Specification Card  indicating  the  start  of  the Aquifer
                     Data Group.

Array Subgroup       Subgroup defining the  aquifer  variables.

Empirical            Subgroup defining any  empirical  distributions.
Distribution
Subgroup

"END"                End Card indicating the end  of this  data  group.
variables are specified to have an empirical distribution,  then  it  is  necessary
to include the Empirical Distribution Subgroup.  When  running  the Surface Water
Module, the user must chose an exposure route.   Figure A. 4  shows the three
options available.  The choice is specified in  the  General  Data  Group.   The end
of the group is indicated by an END CARD.

A. 5. 9  Air Emissions and Dispersion Data Group

The Air Emissions and Dispersion Data Group may consist  of  up  to three subgroups.
The Array and Empirical Subgroups are used to specify  values and distributions
for air emissions and dispersion model variables.   The third subgroup,  the Air
Dispersion Module Control Subgroup discussed in Section  A. 5. 9.1, defines control
options when the air dispersion model is used.

The first card of this group is the GROUP SPECIFICATION  CARD and includes the
code AIR in the first three columns.  The next  set  of  cards, shown  in  Table A-34,
includes an Array Subgroup that contains information about  the
values/distributions of up to 18 variables  (shown in Table  A-35) .   Note that if
any of these variables are specified to have an empirical distribution,  then it
is necessary to include the empirical subgroup.
                                        191

-------
TABLE A-31.   VARIABLES IN THE AQUIFER DATA ARRAY SUBGROUP
    AQUIFER SPECIFIC VARIABLE DATA
    ARRAY VALUES
    ***       AQUIFER SPECIFIC VARIABLES
*** VARIABLE NAME UNITS
***
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Particle diameter (cm)
Aquifer porosity
Bulk density (g/cc)
Aquifer thickness (m)
Mixing zone depth (m)
Hydraulic conductivity (m/yr)
Hydraulic Gradient
Grndwater seep velocity (m/yr)
Retardation coefficient
Longitudinal dispersivity (m)
Transverse dispersivity (m)
Vertical dispersivity (m)
Temperature of aquifer (C)
pH
Organic carbon content (fract)
Receptor distance from site(m)
Angle off center (degree)
Well vertical distance (m)
DISTRIBUTION PARAMETERS LIMITS
MEAN STD DEV MIN MAX
0
-2
-1
0
-1
-2
0
-2
-1
0
0
0
0
0
0
0
0
0
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
0.100E-
0.100E-
0.100E-
0.100E-
0.100E-
0.100E-
0.100E-
0.100E-
1.00
0.100E-
0.100E-
0.100E-
O.OOOE+
0.300
0.100E-
1.00
O.OOOE+
O.OOOE+
08
08
01
08
08
06
07
09

02
02
02
00

05

00
00

0

0
0
0
-
0
0
0
0
0



-

-
100.
.990
5.00
.100E+
.100E+
.100E+
999.
.100E+
.100E+
.100E+
.100E+
.100E+
100.
14.0
1.00
999.
360.
999.



06
06
09

09
09
05
05
05






END ARRAY
    END AQUIFER SPECIFIC VARIABLE DATA
                                                                           192

-------
Table A-32.  CONTENTS AND FORMAT OF THE SURFACE WATER  DATA  GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                                   Format
SU1            "SUR"                                      A3

A1-A3          Array Subgroup                             (See  Table  A-5)

E1-E5          Empirical Distribution Subgroup            (See  Table  A-6)

SU2            "END"                                      A3
                     Definition of Contents
"SUR"                Group Specification Card  indicating  the  start  of  the  Surface
                     Water Data Group.

Array Subgroup       Subgroup defining the  surface water  variables.

Empirical            Subgroup defining any  empirical  distributions.
Distribution
Subgroup

"END"                End Card indicating the end  of this  data group.
A. 5. 9.1  Air Dispersion Module Control Data Subgroup- -

The Control Data Subgroup is identified by a SUBGROUP SPECIFICATION CARD with the
code CON in the first three columns.  The contents  and  format  of  the subgroup are
shown in Table A-36.  The subgroup  is required only if  the  air dispersion module
is used.  Note that the values for  wind speed and the value for FMAT are only
read when IFREQ equals 1.  The available options are  shown  in  Figure A. 5.

If the frequency-weighting approach is used to calculate  long-term dispersion
(IFREQ = 1) ,  frequency data are read from the file  FREQ.IN.  The  file contains
joint frequencies for all combinations of wind speed, direction,  and stability.
For the usual configuration of 16 wind direction sectors, 6 wind  speeds,  and 6
stability classes 576  (i.e., 16 x 6  x 6) joint frequency  entries  are required.
Typically this joint frequency distribution is available  as STAR  (Stability Array
Data)  summaries for airports.  The  general structure  of the data  is illustrated
in Table A-37.  Since users may have this matrix of data  in different formats,
MULTIMED allows some flexibility in the format.  The  formats for  each line of
data are specified by the variable  FMAT on Card AR5 (Table  A-36) .   The end of
this subgroup is indicated by the END CARD.  The completion of the Air Emissions
and Dispersion Data Group is indicated by the END CARD.
                                        193

-------
TABLE A-33.  VARIABLES  IN THE SURFACE WATER DATA ARRAY SUBGROUP
44444444444444444444444444444444444444444'
SURFACE WATER MODULE VARIABLE DATA
ARRAY VALUES
    ***   SURFACE WATER MODULE VARIABLES
VARIABLE NAME
1 Channel slope
2 Stream depth
3 unused at present
4 Mannings roughness
    coefficient
5 Temperature of stream
6 Sediment concentration
7 Stream pH
8 Fract organic carbon in  sedmt
9 Wind speed at elev  z
10 Elev of wind speed measure
11 Fract of fish which is  lipid
12 unused at present
13 Stream flow
END ARRAY
UNITS

(m/m)
(m)


(C)
(mg/1)

sedmt
(m/s)
ure (m)
lipid

(m*3/s)
DISTRIBUTION
MEAN
0
0
0
0
0
0
0
0
0
0
0
0
0
PARAMETERS
STD DEV
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.

1
999
999
999
999
999
999
999
999
999
999
999
999
999
                                                                MIN
   LIMITS
   MAX

0.100E-08 -999.
0.300E-01 -999.
O.OOOE+00 O.OOOE+00
                                                                      0.100E-08
                                                                      0.OOOE+00
           1.00
           100 .
                                                                      0.100E-08 -999.
                                                                      0 .300
                                                                      0.100E-08
                                                                      0.OOOE+00
           14 .0
           1.00
           200 .
                                                                      0.100E-08 -999.
                                                                      0.100E-C
                                                                                 1.00
                                                                      O.OOOE+00 O.OOOE+00
                                                                      0.100E-08 -999.
END SURFACE WATER MODULE  VARIABLE DATA
                                                                     194

-------
Table A-34.  CONTENTS  AND FORMAT OF THE AIR EMISSION AND DISPERSION DATA GROUP
4444444444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format
AIR             "AIR"                                A3

AR2-AR6         Air  Dispersion Control Subgroup      (See  Table  A-36)

A1-A3           Array  Subgroup                       (See  Table  A-5)

E1-E5           Empirical  Distribution Subgroup      (See  Table  A-6)

AR7             "END"                                A3
                      Definition of Contents
"AIR"                 Group Specification Card indicating  the  start  of the Air
                      Emission and Dispersion Data Group.

Array Subgroup        Subgroup defining the air variables.

Empirical             Subgroup defining any empirical distributions.
Distribution
Subgroup

"END"                 End Card indicating the end of this  data group.
                                        195

-------
TABLE A-35.  VARIABLES  IN THE AIR EMISSION AND DISPERSION  DATA ARRAY
AIR MODULE VARIABLE  DATA
ARRAY VALUES
    ***              AIR MODULE VARIABLES
                                                                                 4444444444444444444444444444444444444444444444444444444444444444444
VARIABLE NAME
                              UNITS
1 Depth of soil  cover         (cm)
2 Temper of waste disp  unit  (C)
3 Porosity of unit
4 Water content
5 Gamma factor
6 Mu exponent
7 Sigma exponent
8 Atmos pump correction factor
9 Empirical enhancement factor
10 5 m/s height  of  rise      (m)
11 Decay coeff in air        (sA-l)
12 Receptor dist frm landfill  (m)
13 Receptor angl frm source (rad)
14 Elevation of  receptor     (m)
15 Mixing height              (m)
16 Std dev of wind  elev ang (rad)
17 Constant wind speed        (m/s)
18 Constant stability condition
END ARRAY

END AIR MODULE VARIABLE DATA
MEAN

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
rRIBUTION PARAMETERS
TD DEV
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
999.
MIN
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
-999.
LIMITS
MAX
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
                                                                             196

-------
Table A-36.  CONTENTS AND FORMAT OF THE AIR  DISPERSION CONTROL DATA SUBGROUP
444444444444444444444444444444444444444444444444444444444444
Card           Contents                             Format

                                                    A3

                                                    315

                                                    6F10.0

                                                    A80

                                                    A3
AR2

AR3

AR4

AR5

AR6
"CON"

ISTBL, ISIGZ, IFREQ

(U(I), I = 1,6)

FMAT

"END"
               Definition of Contents
"CON"          Control card  indication  start  of  the Air Dispersion Control
               Subgroup  (required only  if  air dispersion is simulated) .

ISTBL          Flag indication  if terrain  correction is stability dependent.
         0     Stability-independent  terrain  correction
         1     Stability-dependent  terrain correction

ISIGZ          Flag for vertical dispersion coefficient method.
         0     The Pasquill-Gif ford method
         1     The turbulence-intensity method

IFREQ          Flag indicating mode for calculation of oncentrations .
         0     Concentrations are calculated  assuming a constant wind in the
               direction of  the receptor
         1     Wind-stability frequency-weighting approach used

U(l)           Wind speeds for each wind speed class
               (required only if IFREQ  = 1) .

FMAT           Format for the data  in the  file containing wind-stability
         frequency data  (required only  if  IFREQ  = 1) .   The general
   structure of this file is illustrated in Table A-37.
"END"
               End Card indicating  the  end  of  this  data subgroup.
                                        197

-------
Table  A-37.   GENERAL STRUCTURE OF  THE WIND-STABILITY FREQUENCY  FILE  (FREQ.IN)
4444444444444444444444444444444444444444444444444444444444444444444
Wind Direction Sector
1
2
3
4
5
6
7
8
9
10
11
12
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
Frequencies
for
for
for
for
for
for
for
for
for
for
for
for
six
six
six
six
six
six
six
six
six
six
six
six
wind
wind
wind
wind
wind
wind
wind
wind
wind
wind
wind
wind
speed
speed
speed
speed
speed
speed
speed
speed
speed
speed
speed
speed
classes,
classes,
classes,
classes,
classes,
classes,
classes,
classes,
classes,
classes,
classes,
classes,
sector
sector
sector
sector
sector
sector
sector
sector
sector
sector
sector
sector
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
stability
stability
stability
stability
stability
stability
stability
stability
stability
stability
stability
stability
class
class
class
class
class
class
class
class
class
class
class
class
A
A
A
A
A
A
A
A
A
A
A
A
                                             198

-------
                                    APPENDIX B
                         SUBROUTINES INCLUDED IN MULTIMED
Subroutine    Called By

Input/Output Routines

ADISRD           BATIN
AIRIN



BATIN





CHKEND

COMRD




FRQPLT

FRQTAB



ICHECK



LEFTJT

MODCHK



OPENF



OUTFOR



Subroutine

PRINTO
              MAIN



              MAIN





              BATIN,  READLF

              ADISRD,  AIRIN




              OUTFOR

              OUTFOR



              READZ,  READ3
              BATIN,  READLF

              PRTINP,  BATIN

              MAIN
              MAW
              exist.

              MAIN
              Called Bv
              MAIN,  PRTOUT,
              PRNTVZ
standard deviation,  and maximum
                                   Description
Reads input data necessary to run the
Air Emissions Module and the Air
Dispersion Module.

Interactive preprocessor for Air
Dispersion Module.

The batch-run input processor that reads
from a user-specified file the values of
variables and parameters updated from
their default values.

Checks for the end of a data group.

Searches for data lines in input file.
Separates connects from data input
data file.

Prints a CDF and/or PDF to output file.

Prints a table of statistics to the
output file.

Separates data for connections in input
data file.

Left justifies character variables.

Flags which modules are to be run for
Monte Carlo simulations.

Opens files.  Checks to see if they
Outputs single statistics, frequency
distribution tables, CDF tables, and
printer plots.
Description

Outputs the distribution type, mean,
                                   and
PRNEMP
PRNTIN
PRNTVZ
                 PRTOUT, PRNTVZ
                 PRTINP, PRTOUT
                 PRTINP
                                   minimum allowed values for all the
                                   variables which can be generated by
                                   Monte Carlo routines.

                                   Prints empirical distributions to output
                                   file.

                                   Writes out General Data Group to the
                                   output file.

                                   Outputs model parameters for the
                                       201

-------
PRTINP
PRTOUT
                 MAIN
                 MAIN
READ2            BATIN, ADISRD,
                 READLF
   batch input preprocessor.
RE AD 3
BATIN, ADISRD,
                 READLF
   as the batch input preprocessor.
READLF

SOPEN
BATIN

MAIN
Saturated Zone Module

DBK1             STEADY

CONV02           GWCALC
CPCAL
CONV02
                     Unsaturated Zone Flow and Transport
                     Modules to the computer-generated batch
                     input file.

                     Outputs model parameters to the
                     computer-generated batch input file.

                     Outputs Monte Carlo information to
                     output file.

                     Reads in array values as part of the
Reads in empirical distributions as part
Reads in Landfill Source Data.

Open output files containing Monte
Carlo output.   These are the *.VAR and
*.OUT files.
Calculates the modified Bessel function.

Couples Unsaturated Zone and Saturated
Zone Modules using the convolution
approach.

Evaluates saturated zone concentrations
at time "T minus tau'  for the
convolution integral approach.
                                       202

-------
ERFC



Subroutine

FUNCT1



GWCALC
TRANSP
Called By

GW2DFT, QROMB,
TRAPZD

MAIN
GW2DFS
GWCALC, GW3DPS
GW2DFT
GW3DPS
GW3DPT
PATCH
QROMB
STEADY
GWCALC, CPCAL,
GW3DPT
GWCALC
GWCALC, CPCAL
                 MAIN
GW2DFT
PATCH
Computes the complementary error
function.

Description

Evaluates the integrand in the
analytical solution.

Main calling routine for saturated zone
model.  Sudicky's analytical solution
for three-dimensional mass transport
problem with a gaussian-distributed
source.

Analytic solution to the saturated
steady-state, two-dimensional, transport
model with a continuous gaussian source
using the Gauss-Legendre quadrature
integration scheme.

Analytic solution to the saturated,
unsteady-state,  two-dimensional,
transport model with a continuous
gaussian source using the Gauss-Legendre
quadrature integration scheme.

Evaluates saturated, steady-state,
three-dimensional transport from a
continuous gaussian source.  Allows for
the effects of partial penetration.

Evaluates saturated, unsteady-state,
three-dimensional transport from a
continuous gaussian source.  Allows for
partial  penetration effects.

Solves for transport in the saturated
zone assuming a patch source.

Preforms integration using Romberg's
method of order 2K  (e.g., K = 2 is
Simpson's rule).

Steady-state solution for contaminant
transport in the saturated zone when
using a  patch source.
                                       203

-------
TMGEN1
Subroutine
TMGEN2
TMGEN3
TRANSP
TRAPZD
                 INITVT
Called Bv
                 INITVT
                 INITVT
PATCH
                 QROMB
Unsaturated Zone Transport Module
ADISPR
COEF
CONV01
DERFC
DGAUSS
EVAL
VTCALC
VTCALC
VTCALC
                 EXPERF
SOLBT, GW2DFS,
STEADY, TRANSP
                 SOLBT
Evaluates times used in convolution
integral to couple the unsaturated zone
and saturated zone transport solutions
(for constant source).

Description

Evaluates times used in the convolution
integral to couple the unsaturated zone
and saturated zone transport solutions
(for pulse source).

Evaluates times used in the convolution
integral to couple the unsaturated zone
and saturated zone transport solutions
(for decaying source).

Transient solution for contaminant
transport in the saturated zone while
using a patch source.

Computes the nth stage of refinement of
an extended trapezoidal rule.
Computes concentrations based on the
steady-state, advective dispersive
equation with first order decay.

Generates coefficients of transformed
solution for each layer.

Evaluates layered unsaturated zone
transport solution by the convolution
method.

Computes complementary error function
with real arguments.

Computes the first N roots and weight
factors for the Gauss-Legendre
quadrature integration scheme.

Evaluates functional values at Gauss
integration points.
                                       204

-------
EXPO




EXPERF




FACTR



Subroutine

LAGRNG

LAYAVE




LINV



SOLAY1



SOLBT




STEHF




VTCALC
EXPERF




SOLAY1




LINV



Called By

SOLBT

INITVT




INITVT



VTCALC, SOLBT



VTCALC, CONV01




VTCALC




MAIN
Unsaturated Zone Flow Module

FPSIl            RAPSON
Computes the exponential function.  Set
function to zero for agreements less
than -170.

Evaluates the product of an exponential
function and the complementary error
function with real arguments.

Function which calculates the factorial
of a number.

Description

Lagrangian interpolation scheme.

Evaluates average saturation and
porosity for each layer in the
Unsaturated Transport Module.

Evaluates coefficients for Stehfest
algorithm.

Analytical unsaturated transport
solution for the first layer.

Evaluates unsaturated zone
concentrations at the bottom of each
layer at specific time intervals.

Evaluates the inverse of the Laplace
transform for solute transport in
layered media.

The main calling routine for the
analytical solution of transport through
the unsaturated zone.
                     Evaluates pressure head based upon
                     relationship between pressure head and
                     hydraulic conductivity and water
                     content.
                                       205

-------
RAPSON
VFCALC
WCFUN
VFCALC
                 MAIN
VFCALC
Air Emission and Dispersion Module

AIRDIS           MAIN
ARCALC



Subroutine

SIGMAZ



VIRT
MAIN



Called By

AIRDIS



AIRDIS
Surface Water Module

CINTER           SWCALC
CMIX
DRINK
FISH
REOX
SWCALC
SWCALC
                 SWCALC
SWCALC
INITST
                 MAIN
Determines pressure head corresponding
to specific flux using modified Newton-
Raphson iteration.
Main calling routine for the one-
dimensional Unsaturated Zone Flow Module.

Evaluates the water content-pressure
head relationship.
Computes the ground-level concentration
at receptors located downwind of the
landfill.

Calculates the emission rates from the
waste disposal unit to the atmosphere.

Description

Computes vertical dispersion
coefficient.

Computes effective source area and
locates the virtual source.
Computes the fraction of the steady-
state continuous mass leaching out of
the waste disposal unit that enters
the stream.

Calculates the instream dilution due to
complete near-field mixing of the
groundwater plume.

Calculates the reduction in stream
contaminant concentration due to
sedimentation in a water treatment
plant.

Calculates the bioaccumulation of toxics
in fish.

Calculates the reaeration coefficient,
using either the Owens, 0'Conner-Dobbins
or Churchill formula, depending on the
stream depth and/or velocity.

Main calling routine for Surface Water
Module.
                                       206

-------
Landfill Source Module

DISC             INITVF
EVPT
LFCALC
LINER1
                 LFCALC
                 MAIN
                 INITLF
                     Discretizes the landfill layers and
                     unsaturated zone layers into a one
                     dimensional grid for computing pressure
                     head.

                     Computes actual evapotranspiration using
                     a limiting soil moisture calculation.

                     Main calling routine for the Landfill
                     Module.

                     Computes the effective permeability of a
                     landfill layer with a synthetic liner.
Subroutine       Called By

PERC             LFCALC
RUNOFF
LFCALC
Initialization Routines

TRANS            SWCALC
INITAR
                 MAIN
INITGW
                 MAIN
INITLF
INITST
                 INITVF
                 MAIN
INITVF
                 MAIN
Description

Computes pressure head, water content,
and saturation distribution below a
lateral drain.

Computes runoff by SCS curve number
method modified to include the soil
moisture.
                     Calculates the contaminant concentration
                     in the stream at the location of the
                     drinking water treatment plant intake.
                     Assumes first order decay.

                     Assigns the input values or values
                     generated by the Monte Carlo routines
                     to the variable names used in the air
                     emissions and dispersion models.  Also
                     calculates coefficients needed by the
                     models.

                     Assigns the input variables or values
                     generated by Monte Carlo routines to the
                     variable names used in the saturated
                     zone model.  Calculates aquifer,
                     chemical, and source constants.

                     Assigns the input variables or values
                     generated by Monte Carlo routines to the
                     variable modes used in the Landfill Model.

                     Assigns the input values or values
                     generated by the Monte Carlo routines to
                     the variable names used in the Surface
                     Water Module.  Also calculates
                     coefficients needed by the module.

                     Assigns the input variables or values
                     generated by the Monte Carlo routines to
                     the variable names used in the
                     Unsaturated Flow Module.  The initial
                     conditions and coordinate system for the
                     Unsaturated Flow Module are defined here.
                                       207

-------
INITVT
                 MAIN
Subroutine       Called By

Monte Carlo Routines
ANRMRN
   LOGNOR

CALLS
COUNT
EMPCAL
                 NORMAL
UNCPRO
                 MAIN
CALLS
EXPRN
EXPRND
                 EXPRND
                 CALLS
                     Assigns the Unsaturated Transport input
                     variables or values generated by Monte
                     Carlo routines to their variable names.
                     Assigns retardation and saturation to the
                     appropriate transport variables.

                     Description
Generates a (0,1)  normally distributed
random number.

Calls the prescribed random number
generator for each parameter which is
used in the Monte Carlo simulation.

Count the number of parameters which
are to be Monte Carloed.

Generates a random number from an
empirical distribution.  EMPCAL
generates a uniform random number
between 0-1 and uses it to interpolate
for a value using the piecewise linear
cumulative frequency distribution input
by the user.

Generates an exponentially distributed
random number with a mean of 1.

Generates an exponentially distributed
random number with a specified mean.
                                       208

-------
LOGNOR
CALLS
LOG10U
NORMAL
CALLS
CALLS
Generates a lognormally distributed
random number with a specified mean and
standard deviation.  The input mean and
standard deviation are in arithmetic
space.

Generates uniformly distributed loglO
numbers between 0-1, then transforms
them to a range specified by the user.

Generates a (x,a)normally distributed
random number where x is the mean and a
is the standard deviation.
PRMLIS
UNCPRO
UNFRN
UNIFRM
CHMOD, AQMOD,
SOMOD, VTMOD,
VFMOD, ARMOD,
STMOD
RANSET
TRANSB
Subroutine
TRNLOG
MAIN
CALLS
Called
CALLS


By

                 MAIN
ANRMRN, LOG10U
UNIFRM, EXPRN

CALLS, EMPCAL
In the interactive mode, lists the
present,  minimum, and maximum values
and distribution values for the user-
specified variables.

Initializes the random number generator.

Transforms a number from SB space to normal
space or from normal space to SB space.

Description

Transforms the mean and standard
deviation in the arithmetic space (original
data) to mean and standard deviation in
logarithmic (normal) space.

Generates random values for the model
parameters.  It also writes to the
output file if any errors occur when
generating the random values.

Generates a (0,1) uniformly distributed
random number.

Generates a uniformly distributed random
number between a user-specified minimum
and maximum.
Subroutines to Set Default Values and Interactive Routines
AQNAMS
                 MAIN
                     Sets Aquifer Data Group variable and label
                     names.
ARNAMS
                 MAIN
                     Sets Air Data Group variable and label
                     names.
CHNAMS
                 MAIN
                     Sets Chemical Data Group variable and label
                     names.
DEFAULTS
                 MAIN
                     Sets special default values to lock out
                     certain functions.
LFNAMS
                 MAIN
                     Sets Landfill Data Group variable and label
                     names.
SONAMS
STNAMS
                 MAIN
                 MAIN
                     Sets Source Data Group variable and label
                     names.

                     Sets Surface Water Data Group variable and
                     label names.
                                       209

-------
VFNAMS
                 MAIN
Sets Unsaturated Flow Data Group variable
and label names.
VTNAMS
                 MAIN
Sets Unsaturated Transport Data Group
variable and label names.
ZIPI
                 BAT IN
Used when reading batch files.
                                       210

-------
          .-Opening screen
                     ft Wl I
                     WELCOME TO PREMED, THE PREPROCESSOR FOR  HULTIMED (version 1.0)
                     Type 'aOETER.1.061  for a deterministic application tutorial,  or
                          1 eWONTE.LOG1  for a monte carlo application tutorial


                Select an option?
                Analyze model results
                Execute MULTIMED Model
                Return  to operating system
          -STATUS	
            Editing  a new file
            Application type:  Subtitle D landfill
            Scenario:  Unsaturated and Saturated Zone models
           -INSTRUCT-
                                Select an option using arrow keys
                             then confirm selection with the FZ key,  or
                               Type the first letter of an option.
          HelpiiE  Mexttil  ttatusijj  Oulet»|i  Xpad;Ji  Crond
Figure 2.1   Preprocessor screen  after  installation
.-DATA UINDOU TITLE AND SCREEN MTU 	

.-INSTRUCTION WINDOW TITLE 	 — 	
Mpcg* N«t:R Li.ft.:& Ouiet:|| Xp^fS tand. Oop. ,
DIMENSIONS : BO X 1
CONTENT : MEW OF ABBREVIATIONS FOR AVAIUBLE COMMANDS
FEATURES : COMMANDS ARE ORDERED §T EXPECTED FREQUENCY OF USE
STANDARDIZED SET OF COMMANDS AVAILABLE (SEE TABLE 3-1)
DATA UINOOU
TITLE i UP TO U CHARACTER SCREE* DESCRIPTOR
SCKEH PATHS STtlNS OF 1 -LITTER CODES SPECIFYING PATH
OF OPERATIONS (UP TO « CHARACTERS)
DIHEKSIOin ! 78 X 16 (WITHOUT ASSISTANCE INFO WINDOW)
78 H 10 (WITH ASSISTANCE INFO WINDOW!
CONTENT t PROMPTS FOR DECISIONS OR DATA. ECHOES OF
STATE OF DATA, OR RESULTS OF OPERATIONS
FEATURES : ACCOMMODATES DATA FILE OF HAXIKM
DIMENSIONS n X 50 WITH SCROLLING
DATA RANGE : LINES OF DATA CURRENTLY DISPLAYED
TITLE I HELP, COMMANDS, LIMITS, STATUS OR XPAD
DIMENSIONS ; 78 X *
CONTENT : INFORMATION PROVIDED IT PROGRAM (COMMANDS,
KELP.LINITS.STATUS) OR BY USER (XPADJ
HELP - DETAILED USER ASSISTANCE FOR SCREEN CONTENTS
COMMANDS - DEFINITIONS OF AVAILABLE COMMANDS
LIMITS - RANGE OF ACCEPTABLE VALUES
STATUS - SYSTEM STATUS INFORMATION
XPAD - USER NOTES AND REMINDERS
VERTICAL DIMENSION
INSTRUCTION HINDOW
TITLE t INSTRUCT OR ERROR
DIMENSIONS t 78 X 3
CONTENT 1 SYSTEM GENERATED INSTRUCTIONS AMD
ERROR MESSAGES
FEATURES : DIRECTS USERS TO ACCEPTABLE KEY STROKES
               3.1 Screen format utilized by the pre- and postpro.
•








UELCONE TO PRENED,
Type '9DETER.LOG'
'aNONTE.LOG'
Select an option?
Analyze model results
Execute HULT1HED Model

THE PREPROCESSOR

FOR NULTIHED (version 1.0)
for e deterministic tutorial, or
for e monte carlo

mtfrnimmmm

application tutorial



Return to operating system .

Select a
then conftr
Type the


in option using arrow keys
n selection with the F2 key, or
first letter of en option.





"


Htlp:|J next:! Xpadtl Cmnd
        Figure 3.2   Example of a  two window, one commandline screen.

-------







^^ UELCONE TO PREKED, THE PREPROCESSOR FOR MULTIMED (version 1.0)
Type 'aDETER.LOG' for • deterministic eppllcatlon tutorial, or
'atONTE.LOG1 for a nonte carlo application tutorial
Select an option?
wumw^-™>>&**!**&
Analyze model results
Return to operating system
r-STATUS 	 	 	 • 	 ' '
Editing a new file
Application type: Subtitle D landfill ,
Scenario: Unaaturtted and Saturated Zone models
[INSTRUCT 	 — 	 	
Select an option using errow keys
than confirm selection tilth the FZ key, or
Type the first letter of an option.
Help:»J «ext:|l Statue:! Ou1*t:|| Xped:ji Onnd Onpg














Figure 3

Modify de»lr«d Control Parameter*
MMAT - number of different porous materials > 1
KPROP - Van Genuchten or Brooks/Corey paranater* > ST$$li
NVFLAY - Number of physical flow layers > 1
:
Indicates the type of relationships of relative permeability 	
versus saturation, and pressure head versus saturation. • ••'•>
VAHGEN - van Genuchten's functional parameters to be used.
BROOKS - Brooks/Corey functional parameters to be used.
_• «
Enter data in highlighted field(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next' coamand to go to next screen when done entering data. ••<'

-------


Run Title (2 lines)
CASE
Run Option? DETERMINISTIC Transient or Steady-State case? STEADY-STATE
Active modules - Surface water NO Air NO
Unset, zone YES Landfill NO
Saturated zone YES

Editing tests. Inp
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models

Enter data in highlighted fleld(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next1 ccamand to go to next screen when done entering data.
lelp:! Next:! U.tti:|| Status:! °^««:ll Xpad:^| <*"< Oops
	
Figure 3.6. Example of information contained in a, STATUS assistance window.
1

Aquifer thickness (n)
Utiat is the new value? HHHi

Editing tests. Inp
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models

Invalid data Input In highlighted field.
Use 'Limits' conaand to tee acceptable range, or
'Help' coomand to see field definition.
•xt:j| Prev:f| Li»its:fJ Statu»:f| «ulet:|| Xped:|g Cond Oops



:..,-... 'it<.
WELCOME TO PREMED, THE PREPROCESSOR FOR HULTIHED (version 1.0)
Type '80ETER.LOG1 for a deterministic application tutorial, or
•MONTE. LOG1 for a monte carlo application tutorial
Select an option? '
•m*MMBS»e«Mfssss8$ESSW™sf£S8ssMsss
Analyze model results
Execute HULTIMED Model

Return to operating system


Select an option using arrow keys
then confirm (election with the F2 key, or
] Type the first letter of an option.
Help:! Mext:I| Xpad:;i Cnnd •



Figure 4.1.  Opening screen of the preprocessor.

-------





1

Which Build/Modify option?
Edit ah exUting^lnput sequence Return to Opening Screen


Select *n option uiing arrow key*
then confirn selection with the F2 key, or
Type the first letter of an option.
.lp:l Next:! Xpedil Cmnd

-.'>!•




Figure 4,2  Build/Modify screen of the preprocessor.


Select a Depth and Particle Characteristics option.
R«Mrn^;, ,f« ,*^f«*yw»^»»
list current values
PArticle diameter
POrosity of aquifer
Bulk density
Depth of aquifer
Mixing zone depth

editing a new file ' 	
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models

Select an option using arrow keys
then confirm selection with the FZ key, or
Type the first letter of an option.

-------


j-Edft (BE)



Enter data in highlighted, field(s).
Use carriage return or arrow key> to enter data and move between fields.
Use 'Next1 comand to go to next screen when done entering data.
Help:|| Next: II Prev:|| Llmit»:f<| Xped:|f Cnnd Oops

Figure 4,3.  Edit screen of the preprocessor.


Uhat type of application do you want to create?
Generic

Select an option using arrow keys . , • •
then confirm selection with the fZ key, or
Type the first letter of an option.
l«xt:|| Prev:|| Xpad:^ Ond
i 	
Figure 4.4.  Create screen of the preprocessor:

-------

>

How many Monte Carlo simulations? f|3§
How much output do you want from
each Monte Carlo run? SOME
PALPH- confidence level (in X) for
the four estimated percent) les > 90.

Editing a new file
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models

Enter data in highlighted field(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next' command to go to next screen when done entering data.
elp:|i Next: t-2 Prev:|l Limits:!! Status :|| Ouiet:|| Xpad:|£ Cmnd Oops

Figure 4.6.  General-2 screen of the preprocessor.   This screen is only
activated if the simulation is run in Monte Carlo mode.


Edit which model parameters?
Return to Bui Id screen AQuifer saturated zone parameters
Undef - list undefined data group Air air dispersion parameters
8»nlrSlillpilpl|)^Mfi:lll!^|ij source contaminant source data
surface "surf ace" water parameters Chemical properties of contaminant
Funsat unsaturated zone flow Landfill properties definition
Tunsat unsaturated zone transport

Editing a new file
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models

Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an .opt ion.
Help:?? Next:!? Status:!? Quiet :?S Xpad:|$ Cmnd
	
Figure 4.7.  The Edit screen of the preprocessor

-------


Select an Aquifer option.
Depth and particle character Ut lea of aquifer
TYpe of source for saturated zone model , ^_
Hydraulic and dispersion feTated~paramefers "" ~~
Htsc - temperature, pH, and organic carbon of aquifer
Well • well-related parameters ' ^
Tines at which to calculate concentrations ...
_._.._
Editing a new file
Application type: Subtitle D landfill
Scenario; Unsaturated and Saturated Zone models

[Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an option.
elp:Pji Next: pj! Status :|$ Quiet :$8 Xpad:jf$ Grand
	 	 	
Figure 4.8.  AQuifer screen of the preprocessor.
H

Aquifer porosity
How do you want to define this parameter?
.......
Editing a new file
Application type: Subtitle D landfill
Scenario: Unsaturated and Saturated Zone models
..,„ „, ,„
Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an option.

elp:ii Next:H Prev:B Status: F7 Quiet :«i Xpad:|| Cimd
Figure 4.14. The POrosity screen of the preprocessor for a deterministic
simulation.








Figure
determ

Aquifer porosity
What is the new value? r*ri

Editing a new file
Application type: Subtitle D landfill


Enter data in highlighted fleld(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next1 command to go to next screen when done entering data.
lext:l>2 Prev:Pi Limits:JS Status :P Ouiet:|I Xpad:lS Cmnd Oops
4.15. Screen for specification of Aquifer porosity for
Lnistic simulation.








a

-------
         ,-SOurce (BESo)	

          Select a Source option.
          List     present values
          Undef    -  list undefined param
          INFU    -  infiltration rate
          Area     of waste disposal unit
          Duration of pulse
           SPread  of contaminant source
           RECharge rate
sters       source  decay constant
           initial  concentration
           LEngth  scale of facility
           Width    scale of facility
        ,-STATUS	—	
          Editing a  new  file
          Application  type:  Subtitle D landfill
          Scenario:  Unsaturated and Saturated Zone models
        r-lMSTRUCT-
                              Select an option using arrow keys
                           then confirm selection with the F2 key,  or
                             Type the first letter  of an option.
        Help;!  Next: 12  Status:!  Quiet: ft  Xpadijj  Cmnd
Figure 4.9.    SOurce  screen of the preprocessor.
         -Chemical (BEC)	

           Select a Chemical  option.
           Undef "- list undefined parameters
           Name   - specify chemical to be modeled
           Decay  coefficients (solid, dissolved, overall)
           Hydrol - hydrolysis rate constants and reference temperature
           Coeff  - various coefficients and temperature for air diffusion
           Mole   • molecular definitions, solute vapor pressure and Henry's constant
         -STATUS	—	—	
           Editing a new file
           Application  type:  Subtitle D  landfill
           Scenario:  Unsaturated and Saturated Zone models
          -IMSTRUCT-
                               Select an option using arrow keys
                            then confirm selection with the F2 key,
                              Type the first  letter of an option.
         Help:lit  Next;||  Status:!!  "uiet;*| Xpad-.ll  Cmnd
 Figure 4.10.    Chemical  screen of preprocessor.

-------






I
Figure

Select an unsaturated flow parameter option.
Undef - 1 1st undefined parameters
Control parameter
Spatial discretization parameters
Material properties
Functional coefficients

Editing a new file
Application type: Subtitle 0 landfill
Scenario: Unsaturated and Saturated Zone models

Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an option.
elp:|| Next:!* Status:** Quiet:!* X pad: 19 Cmnd
4.11. Unsaturated Flow (Funsat) screen of the preproces







sor .


Select an unsaturated Transport parameter option.
|v«ur# ~fe *&«$**
Undef - list undefined parameters
Control parameter
Property parameters

Editing a new file
Application type: Subtitle 0 landfill
Scenario: Unsaturated and Saturated Zone models

Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an option.
HeloiSt Next:H Status:!! Ouiet:)i Xped:)! Cmnd •'


Figure 4.12. Unsaturated Transport (Tunsat) screen of the preprocessor.

-------
       r-POrosity (BEAqDPo)-
                    Aquifer porosity

                    What distribution do you want to use?
                    Normal
                    LOGNormal
                    Exponential
                    Uniforn
                                LOGIOuniform
                                EHpirlcal
                                Sb dfstr
                                Derived
       ,-STATUS	
        Editing a new file
        Application  type:  Subtitle D landfill
        Scenario: Unsaturated and Saturated Zone models
       r-lNSTRUCT-
                            Select an option using arrow keys
                         then confirm selection with the F2 key,   or
                           Type the first letter of an option.
       Help:|
Prev:|
Status: I!  Quiet :Jt
Xpad:||  Cimd
igure  4.16.   Porosity screen of the preprocessor  for  a Monte Carlo
imulation.
       -POrosity CBEAcpPo)—

           Aquifer porosity

           Parameter  Ranges

           Minimum?

           Maximum?         none
               Mean?

               Std Dev?
                     none

                     none
       r-STATU
         Editing a new file
         Application type:  Subtitle D  landfill
         Scenario:  Unsaturated and Saturated Zone models
       r-1 NSTRUCT	—	'	~
                          Enter data  in highlighted field(s).
           Use  carriage return or arrow keys to enter data and move between fields.
               Use 'Next'  command to go to next screen when done entering data.
       Next:l3  Prev:Jl  Limits:^  Status :g  Quiet:&  Xpad:l  Cmnd  Oops
Figure 4.17.   Screen showing  required parameters for a  Lognormal
probability  density distribution.

-------

-------



WELCOME TO PREMED, THE P
Type 'aDETER.LOG' for a
'5IMONTE.LOG' for a
Select an option?
Build / Modify input sequenc
Analyze model results
Return to operating system




..
Select an option using arrow keys
then confirm selection with the F2 key, or
Type the first letter of an option.
Help:! Next:! Xped:ji Cmnd


Figure 4.20. Example of a. tutorial screen.






1
Figure 4

WELCOME TO POSTMED, THE POSTPROCESSOR FOR MULTIMED (version 1.0)
Select a plot option.
Return to operating system
Specs of plot
Titles on plot
Plot make plot


Select an option using arrow »=7»
then confirm selection with the F2 key, or
Type the first letter of an option.
gext:|| Prev:|l Xpad:$! Cmnd
.21. Opening screen of the postprocessor.















-------

-------

N

How many MULT I MED runs do you want to plot? 1||

Default: 1 Minimum: 1 Maximum: 3

Enter data in highlighted field(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next' command to go to next screen when done entering data.
ext:|! Prev:|| Limits:!! Quiet:|| Xpad:|$ Cwnd Oops

igure 4.22.  Data-1 screen of the postprpcesssor.








Figure

Name of file containing MULT I MED simulation results?
> ' v» ~ * >« , ss s* * s Y 'r«if :>/>•/• ' V* s
™, sWv>. +' 't /<^»<^Vv*m**.»* " t&t-itto ' •**> f S4>X*A*X^ >Arf** *v»* s*^»

—LIMITS 	 • —
Any character string is acceptable.

i— INSTRUCT 	 — — •
Enter data in highlighted field(s).
iintt fnrrinnft rf^^npn e*r Arrnu t^v^ to ^nt^r data And move between fields.
Use "Next1 command to go to next screen when done entering data.
Help:f! Next:|| Prev:|| Limits:'^ Ouiet:f| Xpad:|| Cmnd Oops
4.23. Data- 2 screen of the postprocessor.










-------
          r-Specs (S)-
               Type of  plot
               Graphics device

               X Axis type
               X win
               X Axis type
               X nun log cycles >
COMUWIV8     Character height >   0.16
DISPLAY        Legend location  >     LR

ARITH          Y Axis type      >   ARITH
    0.         Y min           >       0
  0.01         Y max           >     100
    4         Y nun log cycles >       4
          ,-INSTRUCT'
                             Enter data in highlighted field(s).
             Use carriage return or arrow keys to ente'r data and move between fields.
                 Use 'Next1 command to go to next screen when done entering data.
          Help:H  Next:ll  prev:H  Limits:H  Xpad:f$  Grand  Oops
Figure  4.24.   Specs screen of the  postprocessor.


—Titles (T) 	
Main title:
Mumwai mt-JLj ,::*,:C^LT, ;* ' 	
Y Axis label:
Cumulative Frequency
X Axis label:
Concentration
Curve labels:
1: Run 1 2: Run 2 3: Run 3

Enter data in highlighted field(s).
Use carriage return or arrow keys to enter data and move between fields.
Use 'Next' command to go to next screen when done entering data.
Next:f| Prev:|| Limits:|| xpad:l| Cmnd Oops

 Figure  4.25.   Titles screen of  the  postprocessor.

-------
                                                  •-••S  *.•!•
                       Cen»*itr*t.im (rnQSl)
                          ru_iirfS> mjn
„. ai
                      0.
.  n .  fl.  n  .  n
    I   *.•*!
                   •-••! ».»•< «.«tt  *.*!•  t.»IT •••IB  •••••  *.*!•
                          HUl-TiHCP

-------




















k



CURVE NUMBER:
CONC
0.55923E-05
0.10370E-04
0.12765E-04
0.19671E-04
0.21278E-04
0.21345E-04
0.21498E-04
0.25470E-04
0.29032E-04
0.324BOE-04
0.33341E-04
0.36069E-04


'Next' coomand to
ext:|| Prev:|l Xpad:! Onnd



1 Run 1
PERCENT
0.400
0.800
1.200
1.600
2.400
2.800
3.200
3.600
4.000
4.400
4.800
5.200


go' to next screen






















Igure 4.28.  Example  of screen  showing a TEXT file (corresponds to
uaulative frequency plot  shown  in Figure 4.26).
                                Collect Site-Specific
                                Hydrogeological Data
                              Determine Active Modules
                              in HULTIKED; Contaminant
                                  to Be Simulated
                             Propose Landfill Design and
                             Determine Infiltration Rate
                                   Run HDLTIMED
                                   Calculate DAT
                                           yes
                                    Acceptable
                                      Design

-------
                                       Well Location
        WASTE
        FACILITY
                                   y, = R sin
                 PLAN VIEW
       Waste Facility
                         Ground Surface
wwwwvwwvw^^
               SECTION VIEW

-------
   100
J-  10
                      I
                      1
                       o  .
                         o
0.
CO
           ox
          A*
   .   
-------
STRUCTURE OF
INPUT DATA FILE
   Title Card
 Continuation ot
    TaieCatd
  Group 1 Data
  Group 2 Data
  Group N  Data
      I
    End Card
     STRUCTURE OF
EACH GROUP OR SUBGROUP
     Group/Subgroup
    Specification Card
       Data Card 1
                                             Data Card 2
                                            Data Card M
                                              End Card

-------
MATH
















- OPENF
- SOPEN
- COUNT
- MODCHK ,- ADPRNT
- RANSET - PRNEMP
	 PRINTO
•PTCTTNP i — PRTNTO
1 PRNTVZ -1
nilTPIIT i FROTAB ' — PHWEMP
1— FRQPLT
- AQNAMS
- ARNAMS
- CHNAMS
- LFNAMS
- SONAMS
- STNAMS
- VFNAMS
- VTNAMS
— DEFAULTS
- INITGW
— INITAR r- DISC
TMTT17T7 ' TNTTT F 	 LINERl

- LAYAVE
- TMGEN2
1— TMGEN3
TMTT<;T - — 	 - REOX
i-mrrrn TATT0 — r — TRNLOG
- TRANSB
TTYUPNn 	 — FXPRN 	 1

— EMPCAL 	 1
	 m „., 1 UNJFRH—
rnrinn - — UNIFRN


-------
MAIN -i






















- CHKEND 	


- ARCALC

1— SIGMAZ


L- RUNOFF
- GW3DPT-,

GW3DPS ' GW2DFS

- ADISPR
— COEF
— STEHF ,— DERFC
- SOLAY1 	 EXPERF-
*- EXPO - DGAUSS
- CONV01-, ,- EVAL
- SOLAY1 — EXPERF— ,— DERFC
L- EXPO
PATCH STEADY
1 L DBK1
' TRANS P
1— ERFC 	
•— C INTER
- CMIX
- DRINK
I— FISH

-------
       TIME
     DEPENDENCE,
                        STEADY STATE
                        UNSTEADY STATE
      LOCATION OF
        WELL
                      tVCHK.t.ttCHK.0
                                    REJECT WELL LOCATIONS
                                  OUTSIDE PLUME IN VERTICAL AND
                                     TRANSVERSE DIRECTION
     REJECT WELLS SCREENED
  BELOW PLUME IN VERTICAL DIRECTION
                                     REJECT WELLS OUTSIDE •
                                   PLUME M TRANSVERSE DIRECTION
                      ITCHK.IICHK.I
                                      DO NOT REJECT ANY
                                       WELL LOCATIONS
EXPOSURE
  ROUTE
                   ROUTED
                   ROUTE=3
                                HUMAN EXPOSURE THROUGH
                                     DRINKING WATER
HUMAN EXPOSURETHROUGH
    FISH CONSUMPTION
                                   EXPOSURE TO AQUATIC
                                        ORGANISMS

-------
 TERRAIN
OORRECnON
  STABILITY DEPENDENT
NOTSTABUTY DEPENOENT
                                VERTICAL
                               DISPERSION
                              CALCULATION
                                                          MEIHOO
                                                                            TURBLLBCE
                                                                          MTBSTTY MEIHOO
          CONSTANT WIND
       AND STABUTY CONDITION
      RESULTS WEK3HTH) BY JONT
         Fneoueccs OF WMO
           AND STABILITY

-------



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ID"7
10"
10"
io-»
IO"1
•ID-'
.o-z
ID*3
10"
10"
10"
io-7
10
10"
10-"
10'«
o-
rIO*
•10s
K)4
10s '
•10*
•10
1
•10"
10'2
ID'3
ID'4
ID"5
10"
io-7
ti Conversion Factors for Permeability
and Hydraulic Conductivity Units
Permeability, *• Hydraulic conductivity. K
cm1
cm1 |
ft: 9.29 x 10*
darcy 9.87 x I0"»
m's J.02 x IO-»
U.S-ial/day/ft-'5.42xlO-"»
(l* «1»'CV m/t ft/« U.S. Bal/Oty/fl'
1.08 x 10-> 1.01 x 10* 9.80 x 10* 3.22 x I0» 1.85 x 10«
1 9.42xlO<* 9.11 xlO> 2.99x10* 1.71 x 10>*
1.06 x IO-»« | 9.66 x 10-* 3.17 x lO'i 1.82 x 10'
I.IOxlO-* I.04xl0» 1 3.28 2.12x10*
3.35x10-' 3.15x10* 3.0SxlO-« 1 6.46 x!0«
5.83 x IO-»» 5.49 x 10-* 4.72 x 10"' 1.55 :< 10** J
•To obtain * in fi», multiply * in em* by 1.08 x 10''.

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