&EPA
           United States
           Environmental Protection
           Agency
           Office of Research and
           Development
           Washington DC 20460
EPA/600/R-94/039a
April 1994
The Hydrocarbon
Spill Screening
Model (HSSM)

Volume I: User's
Guide
                                    (   I

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,;>                                                                     EPA/600/R-94/0393
^                                                                    April 1994
O
             THE HYDROCARBON SPILL SCREENING MODEL (HSSM)
                                VOLUME  1:  USER'S GUIDE
                                                by
                                          James W. Weaver
                             Robert S. Kerr Environmental Research Laboratory
                               United States Environmental Protection Agency
                                        Ada, Oklahoma 74820

                                  Randall J. Charbeneau, John D. Tauxe
                                    Department of Civil Engineering
                                   The University of Texas at Austin
                                         Austin, Texas 78712

                                            Bob K. Lien
                             Robert S. Kerr Environmental Research Laboratory
                               United States Environmental Protection Agency
                                        Ada, Oklahoma 74820

                                               and

                                         Jacques B. Provost
                                    Computer Sciences Corporation
                                        Ada, Oklahoma 74820
                                       U.S. Envi-      '  •• -Action Agency
                                       Region 5,!  '         - ;;.
                                       77 West J:,,,         -.^H  i^u r,
                                       Chicago,  IL  t^.4-3590   ™ F'°°r
                             Robert S. Kerr Environmental Research Laboratory
                                  Office of Research and Development
                                  U.S. Environmental Protection Agency
                                       Ada, Oklahoma 74820
                                                                   Printed on Recycled Paper

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Disclaimer
       The information in  this document  has been  funded wholly  or  in part by the United States
Environmental Protection Agency, through  direct  support of the  EPA authors, cooperative agreement
CR-813080  to the University of Texas at Austin,  Contract 68-C8-0058 with Dynamac Corporation, and
Contract 68-W1 -0043 with Computer Services Corporation. It has been subjected to the Agency's peer and
administrative review, and it has been approved for publication as an  EPA document.  Mention of trade
names or commercial products does not constitute endorsement or recommendation for use.

       All research projects making conclusions or recommendations based on environmentally related
measurements and funded  by  the  United  States Environmental Protection  Agency are  required  to
participate in the Agency Quality Assurance Program. This project did not involve environmentally related
measurements and did not involve a Quality Assurance Plan.

       The computer program described within this report simulates the behavior of water-immiscible
contaminants (NAPLs: NonAqueous  Phase  Liquids) in idealized  subsurface systems.  The approaches
described are not suited for application to heterogeneous geological formations, nor are they applicable to
any other scenario other than that described herein. The model is intended to provide order-of-magnitude
estimates of contamination levels only. The full model has not been verified by comparison with either lab
or field studies. Therefore the EPA does not endorse the use of this computer program for any specific
purpose. As in the case of any subsurface investigation, the scientific  and engineering judgement of the
model user is of paramount importance.  Any model results should be subjected to thorough analysis.  In
this user's guide, typical values are given for various parameters.  These are provided  for illustrative
purposes only.

       When  available, the software described in this  document  is supplied on an  "as-is" basis without
guarantee or warranty of any kind, expressed or implied.  Neither  the United States  Government (United
States Environmental Protection Agency, Robert S.  Kerr  Environmental  Research Laboratory), The
University of Texas at Austin, Computer Sciences Corporation, nor any of the authors accept any liability
resulting from the use of this code.

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Foreword

       EPA is charged by Congress to protect the Nation's land, air and water systems. Under a mandate
of national environmental laws focused on air and water quality, solid waste management and the control
of toxic substances, pesticides, noise and radiation, the Agency strives to formulate and implement actions
which lead to a compatible balance between human activities and the ability of natural systems to support
and nurture life.

       The  Robert S.  Kerr Environmental Research Laboratory is the Agency's center of expertise for
investigation of the soil and subsurface environment.  Personnel at the Laboratory  are responsible for
management of  research programs to:   (a) determine the fate,  transport  and transformation  rates of
pollutants in  the soil, the unsaturated and the saturated zones of the subsurface environment; (b) define
the processes to be used in characterizing the soil and subsurface environments as a receptor of pollutants;
(c) develop  techniques for  predicting the effect of pollutants on ground water, soil,  and  indigenous
organisms;  and (d) define and demonstrate the applicability of using natural processes, indigenous to the
soil and subsurface environment, for the protection of this resource.

       One of the most common, yet complex,  class of subsurface contaminants contains the light
nonaqueous phase liquids (LNAPLs). Although the LNAPL itself remains distinct from the subsurface water,
chemical  constituents of the LNAPL can cause serious ground water contamination.  Since a number of
phenomena  and parameters interact  to determine contaminant concentrations at the  receptor points,
models are needed to  estimate the impacts of LNAPL releases on ground water.    This user's guide
describes the Hydrocarbon Spill Screening Model (HSSM) which is intended to simulate  release of an
LNAPL.  The intent of the model  is to provide a practical tool which is easy to apply and runs rapidly on
personal  computers.
                                                                        Clinton W. Hall, Director
                                                                   Robert S. Kerr Environmental
                                                                           Research Laboratory

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Abstract

       This user's guide describes the  Hydrocarbon Spill  Screening  Model (HSSM).   The model is
intended for simulation of subsurface releases of light nonaqueous phase liquids (LNAPLs).   The model
consists of separate modules for LNAPL flow through the vadose zone,  spreading in the capillary fringe,
and transport of chemical constituents of the LNAPL in a water table aquifer.  These modules are based
on simplified conceptualizations of the flow and transport phenomena which were used so that the resulting
model would be a practical, though approximate, tool.  Both DOS and Windows  interfaces are provided
to create input data sets, run the model, and graph the results. These interfaces simplify the  procedures
for running the model so that the model  user may focus on analysis of his/her problem of interest.  To that
end, guidance is given for selecting parameter values and several utility programs are provided  to calculate
certain parameters.   Typical example problems, which begin with a general problem statement, show
exactly how each parameter of the model should be chosen.
                                              iv

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CONTENTS


Disclaimer  	 ii

Foreword  	iii

Abstract	   iv

List of Figures	  viii

List of Symbols	   ix

List of Abbreviations and Acronyms  	xi

Acknowledgment	  xii

Section 1  Introduction	   1
       1.1  The  Meaning of the Name HSSM	   1
              1.1.1 Hydrocarbon  	   1
              1.1.2 Spill  	   2
              1.1.3 Screening Model 	   2
       1.2 Components of the Model	   2
       1.3 Obtaining a Copy of HSSM	   6

Section 2 Assumptions Underlying HSSM 	   7
       2.1  Kinematic Oily Pollutant Transport (KOPT)	   7
       2.2 OILENS	  11
       2.3 Transient Source Gaussian Plume Model (TSGPLUME) 	  12

Section 3  HSSM  Interface Options  	  15
       3.1  Typographical Conventions	  16

Section 4 The MS-Windows Interface, HSSM-WIN	  17
       4.1  Microsoft Windows  Interface Overview	  17
       4.2 System Requirements	  18
       4.3 Installation	  19
              4.3.1 Packing List of Files	  19
              4.3.2 Copying Files  to the Hard  Drive  	  19
              4.3.3 Adding HSSM to a Program Manager Group	  20
       4.4 Using HSSM-WIN	  22
              4.4.1 Starting Up 	  22
              4.4.2 Menu Command Summary	  22
       4.5  Use of HSSM-WIN  Commands for Performing HSSM Simulations	  24
              4.5.1 Creating New  Input Data Sets	  24
              4.5.2 Editing Existing Input Data Sets  	  24
              4.5.3 Running the Model	  25
              4.5.4 Graphing the Model Results 	  26
              4.5.5 Graphing Results From a Previous Simulation 	  26
              4.5.6 Printing a Graph  	  27
              4.5.7 Comparing Several Simulations	  27

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              4.5.8 Copying a Graph to the Clipboard	  28
              4.5.9 Exiting HSSM-WIN	  29
       4.6  Editing and Creating HSSM Data Sets	  29
              4.6.1 Using the Input File Editors - Common Techniques  	  30
              4.6.2 Required Units for HSSM Simulations	  31
              4.6.3 General  Model Parameters	  31
              4.6.4 Hydrologic and Hydraulic Data 	  33
              4.6.5 Hydrocarbon (NAPL) Phase Data  	  40
              4.6.6 Model Simulation Data	  46
       4.7  Running the KOPT, OILENS  and TSGPLUME Modules	  52
       4.8  Graphical Presentation of HSSM Output	  59
              4.8.1 Saturation Profiles  	  59
              4.8.2 NAPL Lens Profiles 	  60
              4.8.3 Contaminant Mass Flux History	  60
              4.8.4 NAPL Radius History 	  60
              4.8.5 NAPL Lens Contaminant Mass Balance	  60
              4.8.6 Receptor Concentration Histories  	  62
       4.9  A Note on the Efficiency of Using the Windows Interface	  62
       4.10 Menu Command  Reference	  63

Section 5 Example Problems  	  67
       5.1  Problem 1: Gasoline  Arrival Time at the Water Table	  67
       5.2  Problem 2: Transport of Gasoline Constituents in Ground Water to Receptor
              Locations 	  76

Section 6 Contents  of the Output  Files  	  84
       6.1  HSSM-KO Output  File	  84
       6.2  HSSM-T Output File	  101

References	  105

Appendix 1 The MS-DOS Interface, HSSM-DOS	  109
       1.1  The HSSM-DOS Menu program   	  109
       1.2  Data Entry in PRE-HSSM  	  109
       1.3  Computation by HSSM-KO and HSSM-T	  110
       1.4  Graphing of Results in HSSM-PLT	  110
       1.5  Quick Summary of the DOS Interface Commands	  110
       1.6  System Requirements	  111
       1.7  Installation	  112
       1.8  Using the PRE-HSSM Preprocessor  	  115
              1.8.1 Saving Data to a File 	  116
              1.8.2 PRE-HSSM Main Menu Commands  	  118
              1.8.3 Creating and Editing HSSM Data Sets	  119
       1.9  Running the KOPT, OILENS  and TSGPLUME Modules	  146
       1.10 Plotting HSSM Results with HSSM-PLT	  152
              1.10.1  Package Requirements	  152
              1.10.2 Overview	  152
       1.11  Graphical Presentation of HSSM Output	  157

Appendix 2  DOS Example Problem	  158
       2.1  Gasoline Arrival Time at the Water Table	  158
                                            VI

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Appendix 3  Sources of Parameter Data	  165
       3.1  Soil Properties  	  165
       3.2  NAPL/Water Partition Coefficient	  173
       3.3  Estimation of the Maximum NAPL Saturation in the Lens	  176

Appendix 4  Approximate Conversion of Capillary Pressure Curve Parameters 	  182

Appendix 5  The Soil Property Regression Utility (SOPROP)  	  185

Appendix 6  The RAOULT Utility 	  187

Appendix 7  The NTHICK Utility	  191
       7.1  Procedure for Using NTHICK 	  194
       7.2  Example NTHICK Calculation Sequence  	  196

Appendix 8  The REBUILD Utility	  197

Appendix 9  Dual Installation of the DOS and Windows Interfaces  	  198

Appendix 10 Direct Editing of HSSM-KO Data Files 	  199

Appendix 11  Direct Editing of HSSM-T Data Files  	  202

Appendix 12 PRE-HSSM Input  Data Templates	  203

Appendix 13 HSSM-WIN Input Data Templates 	  209
                                           VII

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List of Figures
Figure 1  Schematic view of NAPL release	   3
Figure 2  Schematic view of idealized NAPL release that is used in HSSM	   4
Figure 3  HSSM schematic showing the use of each module	   5
Figure 4  HSSM release options  	   8
Figure 5  Comparison of sharp and spreading fronts	   9
Figure 6  Comparison between experimental data and the KOPT model	   9
Figure 7  Lens configuration during thinning phase 	  11
Figure 8  Gaussian source configuration used in TSGPLUME  	  12
Figure 9  Coordinate systems for the KOPT, OILENS and TSGPLUME Modules of HSSM	  13
Figure 10  Schematic representation  of a TSGPLUME concentration history	  14
Figure 11  Installing HSSM-WIN in a Program Manager group	  21
Figure 12  The initial HSSM-WIN screen	  22
Figure 13  File Open dialog box	  24
Figure 14  File Save As dialog box	"	  25
Figure 15  Display Graphs dialog box	  26
Figure 16  Comparison of Graphs from Two Different Simulations  	  28
Figure 17  HSSM-WIN graph pasted  into PAINTBRUSH  	  29
Figure 18  An example of a data entry error message	  30
Figure 19  General Parameters dialog box 	  32
Figure 20  Hydrologic Parameters dialog box  	  33
Figure 21  Hydrocarbon Phase Parameters dialog box	  40
Figure 22  Model Simulation Data dialog box  	  47
Figure 23  Typical saturation profiles  	  61
Figure 24  Typical NAPL lens profile	  61
Figure 25  Typical contaminant mass flux history	  61
Figure 26  Typical NAPL lens radius  history  	  61
Figure 27  Typical NAPL lens contaminant mass balance  	  62
Figure 28  Typical receptor concentration histories 	  62
Figure 29  HSSM-WIN "Help" information in HSSMHELP.TXT	  66
Figure 30  Problem 1  completed General Parameters dialog box	  68
Figure 31  Problem 1  completed Hydrologic Properties dialog box  	  70
Figure 32  Problem 1  completed Hydrocarbon Phase Properties dialog box  	  72
Figure 33  Problem 1  completed Simulation Parameters dialog box  	  73
Figure 34  The storage tank example saturation profiles  	  74
Figure 35  Storage tank facility example with  increased conductivity	  75
Figure 36  Problem 2  completed General Parameters dialog box	  77
Figure 37  Problem 2  completed Hydrologic Properties dialog box  	  79
Figure 38  Problem 2  completed Hydrocarbon Phase Properties dialog box  	  80
Figure 39  Problem 2  completed Simulation Control dialog box parameters	  83
Figure 40  Saturation  profiles	  163
Figure 41  The front position  	  163
Figure 42  Storage tank facility example with  increased conductivity	  164
Figure 43  Comparison of average capillary pressure curves with measured data  	  172
Figure 44  Comparison of equivalent  Brooks and Corey and van Genuchten parameters for sandy
       soil	  183
Figure 45  Comparison of equivalent  Brooks and Corey and van Genuchten parameters for sandy
       clay loam soil	  184
                                             VIII

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List of Symbols

Latin

AL             Longitudinal dispersivity
AT             Transverse horizontal dispersivity
Av             Transverse vertical dispersivity
b0             Observation well NAPL thickness and regression coefficient in equation (42)
bijk             Regression coefficient in equation (42)
C             Constant in equation (41)
Cb             Benzene concentration in gasoline
c0(ini)           Initial chemical constituent concentration in the NAPL
c0)             Concentration of the jth constituent of the NAPL phase
c0             Chemical constituent concentration in the NAPL
cs             Concentration of the chemical constituent sorbed to the porous media
cw             Chemical constituent concentration in water
DL             Longitudinal dispersion coefficient
D0             Average NAPL thickness in the formation
DT             Transverse horizontal dispersion coefficient
Dv             Transverse vertical dispersion coefficient
dpa             Depth at which NAPL is applied
dpl             Specified depth for NAPL boundary condition
fb             Mass fraction of benzene in gasoline
foc             Fraction organic carbon
g              Acceleration of gravity
Hs             NAPL ponding depth at the surface
hc             Capillary head
hce             Air entry head in an air/water system
hcelj            Entry head in a fluid i/fluid j system
hceao           Air entry head in an air/LNAPL  system
hceow           NAPL entry head in a LNAPL/water system
Kd             Sorption coefficient (Soil/water partition coefficient)
KB)             Effective conductivity to fluid j
Keo             Effective conductivity to the NAPL
Kew            Effective conductivity to water
K0             NAPL/water partition coefficient
Koc             Organic carbon partition coefficient
Kw(max)          Maximum relative permeability to water during infiltration
Ks             Saturated hydraulic conductivity (to water)
KS|             Saturated hydraulic conductivity to fluid j
Kso             Saturated  hydraulic conductivity to NAPL
Ksw             Saturated hydraulic conductivity to water
kr|             Relative permeability to fluid j
kra             Relative permeability to water
m             Parameter of the van Genuchten (1980) model
n              Parameter of the van Genuchten (1980) model
Pc, PC(S)       Capillary pressure
pbaw            Bubbling pressure in an air-water system
pbl|             Bubbling pressure in an i-j fluid  system
pdi             Capillary pressure in an i-j fluid  system
pcao            Capillary pressure in an air-NAPL system
                                                IX

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Symbols (Continued)

pcow            Capillary pressure in a NAPL-water system
PC            Percent clay
PS            Percent sand
qw             Water flux
q0             NAPL flux
Rs             Source radius
RT             Aquifer boundary condition radius
S              Saturation
S,             Saturation of fluid j
S.             Particular water saturation given by equation (68)
Sir             Residual saturation of fluid i
S0             NAPL saturation
S0(max)          NAPL saturation in the lens
Sw{maX)          Specified water saturation in the vadose zone
Sore            Saturated zone NAPL residual saturation
Sorv            Vadose zone NAPL residual saturation
S,             Total liquid saturation S, = S0 + Sw
Sw             Water saturation
Swr            Residual water saturation
sk             Solubility of the kth constituent
t               Time
v              Seepage velocity
z              Depth measured from the ground surface, in Appendix 3.3 the height above the water table
zao             In Appendix 3.3 the elevation of zero capillary pressure in an air-LNAPL system
zaw            In Appendix 3.3 the elevation of zero capillary pressure in an air-water system
zow            In Appendix 3.3 the elevation of zero capillary pressure in a LNAPL-water system
Greek

a              Parameter of the van Genuchten (1980) model and constant in equation (60)
P              Function of b0 in equation (60)
yk              Activity coefficient of the klh constituent
Ap,,            Density  difference between fluids i and j
Apao           Density  difference between air and NAPL
t|              Porosity
©j              Reduced wetting phase content
0,              Reduced total liquid content
@w             Reduced water content
0j              Volumetric liquid content of fluid j
0jr              Residual liquid content of fluid j
9m             Maximum water content
00              Volumetric NAPL content
9W              Volumetric water content
6wr             Volumetric residual water content
X,              Brooks and Corey (1964) pore size distribution index
Uj              Dynamic viscosity of fluid j
u0              Dynamic viscosity of the NAPL
uw             Dynamic viscosity of water
pb              Bulk density

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Symbols (Continued)
Pi
P9
Po
Ps
Pw
X
co°
Density of fluid j
Gasoline density
NAPL density
Solids density
Water density
Surface or interfacial tension between fluids i and j
NAPL surface tension
Water surface tension
NAPL/water interfacial tension
Constant in equation (60)
Molecular weight of jth constituent of the NAPL
Average molecular weight of a NAPL phase
List of Abbreviations and Acronyms
CSMoS       Center for Subsurface Modeling Support
DNAPL       Denser-than-water nonaqueous phase liquid
KOPT        Kinematic oily pollutant transport (vadose zone module of HSSM)
HSSM        Hydrocarbon spill  screening model
HSSM-1-d    Distribution diskette name for the DOS version of HSSM
HSSM-1-w    Distribution diskette name for the Windows version of HSSM
HSSM-2      Distribution diskette name for the HSSM example problems
HSSM-DOS   DOS menu program for HSSM
HSSM-KO    KOPT and OILENS portion of HSSM
HSSM-PLT    DOS plotting program for HSSM
HSSM-T      TSGPLUME portion of HSSM
HSSM-WIN    Windows interface program for HSSM
LNAPL       Lighter-than-water nonaqueous phase liquid
NAPL        Nonaqueous phase liquid
OILENS      HSSM Module for NAPL lens motion and chemical dissolution into the aquifer
PRE-HSSM    DOS preprocessor for HSSM
RSKERL      Robert S. Kerr Environmental Research Laboratory
TSGPLUME   Transient source gaussian  plume model (aquifer module of HSSM)
USEPA       United States Environmental Protection Agency
                                          XI

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Acknowledgment
       The authors express their appreciation to Susan Roberts-Shultz for the original development of
OILENS, to Mike Johnson for the original development of TSGPLUME, to Donald Colllngs for developing
the DOS preprocessor, to Mark Lee for developing the REBUILD and DOS menu programs, to Julia Mead
and Sarah Hendrickson for repeated testing of  HSSM  test data sets; and to  Dr. Jeffrey A. Johnson,
Dr. Varadhan Ravi and Rick Bowers for extensive beta testing.
                                           xii

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Section 1   Introduction

       When fluids that are immiscible with water (the so-called nonaqueous chase liquids or NAPLs) are
released in the subsurface, they remain distinct fluids, flowing separately from the water phase.  Fluids less
dense than water (LNAPLs) migrate downward through the vadose zone, but upon reaching the water table,
tend to form lenses on top  of the aquifer.  Generally, the fluids are composed of complex mixtures of
individual chemicals, so that aquifer contamination results from the dissolution of various constituents of
the LNAPL.  This document describes a screening model called the Hydrocarbon  Spill Screening Model
(HSSM) for estimating the impacts of this type of pollutant on water table aquifers. The model is based
on approximate treatments of flow through the vadose zone, LNAPL spreading along the water table, and
miscible transport of a single chemical constituent of the LNAPL through a water table aquifer to various
receptor points. Emergency response, initial phases of site investigation, facilities siting, and underground
storage tank programs are potential areas for use of HSSM.

       The user's guide is organized into sections that describe the assumptions underlying  the model,
the required input data and  the mechanics of running the model.  Separate MS-DOS and MS-Windows
interfaces are provided for the model.  Each interface has the capability to enter and edit input data sets,
run the model,  and display graphs of the results. The advantages and disadvantages of each interface are
briefly described in order to aid the user  in selecting the appropriate interface for his/her hardware and
software configuration. Following the description of the interfaces, several example problems are presented
that illustrate the steps necessary for setting up and running the model.


1.1   The Meaning of the Name HSSM

       Each word in the name of the model is used below as a point-of-departure for a discussion of some
issues related to use of the  model. Specific information on the model's parameter values and directions
for use of the model are given in later sections.
1.1.1  Hydrocarbon

       In HSSM, the LNAPL (or hydrocarbon) is assumed to be composed of two components.  The first
component is the LNAPL itself, which is a liquid that is separate from and does not mix with the subsurface
water.  The model contains a set of equations for tracking the motion of the LNAPL phase.  Several of the
results and graphs produced  by the model depict the  distribution of the LNAPL phase.  The second
component is referred to as a chemical constituent of the LNAPL, because typical LNAPLs  are composed
of many individual chemicals.  HSSM tracks the transport of one of these chemicals.  Since the chemical
constituent may  dissolve into the subsurface  water, it can be  transported by the groundwater  and
contaminate down gradient receptor points.  For example,  HSSM may  be  used to simulate a  gasoline
release. Benzene could be the chemical constituent of interest.  All of the rest of the chemicals composing
the  gasoline would  be treated as being part of the LNAPL.  When the impact of another constituent of
gasoline, say toluene, needed to be determined, the chemical constituent would be the toluene.  In this
way, HSSM could be run for several of the important chemical constituents of the LNAPL. The model user
could develop a feel for the behavior of the different chemicals by comparing the results.

       HSSM  is designed for LNAPLs.  It is not suitable for denser-than-water NAPLs (DNAPLs) as the
NAPL is assumed to "float" on the water table.  The vadose zone module of HSSM (Section 2.1) could,
however, be used for a DNAPL, as the qualitative behavior of that module is not affected by fluid density.
                                                                        [Section 1  Introduction]

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1.1.2  Spill

       Spill is used as a generic term for a release of LNAPL. The release may be a spill, leak or other
event which allows the LNAPL to enter the subsurface.  In HSSM some details of the release must be
known as they are required for input to the model.  These details may include the beginning and ending
times of the release, the rate of release of the LNAPL or the ponding depth  of the LNAPL at the surface.


1.1.3  Screening Model

       Screening models may include a variety of chemical and hydrological processes, but usually do
not include subsurface heterogeneity. Most screening models are in the form of analytical solutions of their
governing equations.   Simplifications must usually be made in order to get these analytical solutions. As
a result, computer implementations of screening models use only relatively small amounts of computer time.
In general,  screening  models can  be used to  estimate the impacts of  contamination,  given  their
assumptions.  The  HSSM  is  a  screening model;  it includes a number of chemical  and hydrologic
phenomena, assumes subsurface homogeneity, executes rapidly on PCs, and excludes some phenomena.
For example, if  gasoline is spilled, HSSM may  be used to give a rough estimate of ground water
concentrations of constituents of the gasoline. The model is intended only to give order-of-magnitude
results, because  a number of potentially important processes are treated in the model in  an approximate
manner or are ignored entirely. Also, one would not expect to calibrate the model by adjusting the spatial
distributions of the parameters, as heterogeneity is not included in  the model.

       If simulation of complex heterogeneous sites is  needed or other approximations  made in HSSM
are unacceptable, then a more  inclusive model, such as the MOFAT code developed at Virginia Polytechnic
Institute (Kuppusamy et al., 1987); the SWANFLOW code developed by Geotrans, Inc.  (Faust, 1985); the
MAGNUS code  developed  by Hydrogeologic, Inc.  (Huyakorn and Kool,  1992); or the VALOR code
developed by The Electric Power Research Institute (Abriola et al., 1992) should be used  instead of, or in
addition to, HSSM. Potential users of HSSM should pay close attention to the following discussion of the
assumptions and limitations of the model, so that they may make an informed decision on the use of the
model.
1.2  Components of the Model

       Figure 1  shows a typical release of a LNAPL pollutant at the ground surface.  The LNAPL flows
downward through the vadose zone due to gravity and capillary forces.  The LNAPL is deflected from its
downward path by geologic heterogeneities it encounters on  its way toward the water table.  Infiltrating
rainwater may push the LNAPL down faster than it would move  on its own.  Once in the vicinity of the
water table, the LNAPL floats in the capillary fringe since it is a nonwetting phase that is less dense than
water.  Fluctuation of the water table due to natural causes or wells may create a smear zone  containing
trapped LNAPL.  Contact with  the ground water or infiltrating recharge water causes the chemical
constituents of the LNAPL to dissolve, resulting in aquifer contamination. The constituents may be leached
at different rates due to their diverse properties.  Depending on their volatility, the constituents also partition
into the vadose zone air.

       Once in the aquifer, limited mixing leaves the constituents in a relatively narrow band near the top
of the aquifer.  These constituents are transported by advection and dispersion through the aquifer.  The
aquifer, like the vadose zone, is heterogeneous and flow may follow preferential pathways.

       The  HSSM is based  on a simplified conceptualization of  a  LNAPL  release.  Figure 2  shows the


[Section 1 Introduction]                        2

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geometry assumed for HSSM, which is a simplified version of the scenario described in Figure 1.  Within


                                                Land Surface
                             Low Water Table


                                       Aquifer
Figure 1  Schematic view of NAPL release
HSSM, the LNAPL follows a one-dimensional path from the surface to the water table.  Properties of the
subsurface are taken as being uniform.  The LNAPL is composed of two components: one is the LNAPL
phase and the other is the chemical constituent of interest. At the water table, the LNAPL spreads radially,
which implies that the regional gradient has no effect on the flow of the LNAPL. Dissolution of the chemical
constituent obeys local  equilibrium partitioning, but is driven by the flowing ground water and recharge
water reaching the water table.  The chemical constituent is transported by advection and dispersion to
multiple receptor points in the uniform aquifer. Further details on these assumptions are given below.

       The model is composed of three modules, based on the simplified conceptualization presented
above.  All of the modules are in the form of semi-analytical solutions of the governing equations, so the
modules of HSSM  do not use discretization of the flow domain nor iterative solution techniques.  These
approximations are designed to execute  rapidly.  The conceptual basis of the modules is discussed in the
following paragraphs.   The mathematical details  of the modules are found in The Hydrocarbon  Spill
Screening Model (HSSM) Volume 2:  Theoretical Background (Charbeneau et  al., 1994).

       The model  is intended to address the problem of LNAPL flow and transport from the ground surface
to a water table aquifer.  Assuming that the principle interest lies with water quality, an emphasis of the
model is the determination of the NAPL lens size and the mass flux of contaminants into the aquifer.
These quantities define the source condition for aquifer contamination and must be based upon multiphase
flow phenomena  in the vadose zone.  The first two modules of HSSM address the vadose zone flow and
transport of the LNAPL.  These two are the Kinematic Oily Rollutant Transport  (KOPT) and OILENS
modules.  KOPT and OILENS are combined  into one computer code, HSSM-KO, which provides a time-
variable source condition for the aquifer  model.

       A chemical constituent dissolved in both the LNAPL and water phases  is tracked by KOPT and
OILENS. Once that chemical constituent reaches the water table, it contaminates the aquifer by contact
with the recharge water and  by dissolution from the LNAPL lens.  Thus, the third part of the model is
transported through the aquifer of one chemical constituent of the LNAPL.  Notably, the mass flux from

                                              3                         [Section 1 Introduction]

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OILENS is time varying, so that the aquifer model must be capable of simulating a time varying source
condition.  In keeping with the level of approximation used in KOPT and OILENS, one suitable choice is
the Transient Source Gaussian Plume  (TSGPLUME) model, which  uses an analytical solution  of the
advection-dispersion equation. TSGPLUME uses different numerical techniques than KOPT and OILENS;

                                                  Land Surface
                                                   Vadose Zone
                                                NAPL
                                      Aquifer
Figure 2  Schematic view of idealized NAPL release that is used in HSSM

so it is not incorporated within HSSM-KO, but rather is implemented in the computer code HSSM-T.  The
TSGPLUME model takes the dissolution mass flux from the OILENS module of HSSM-KO and calculates
the expected concentrations at a number of down gradient receptor points.

       Table 1 summarizes the component modules of the HSSM.  Note  that the names KOPT, OILENS
and TSGPLUME refer to the mathematical models, while HSSM-KO and  HSSM-T refer to the computer
implementations of the models.
Table 1 Implementation of HSSM modules
Subsurface Region
Vadose zone
Water table
Aquifer
Mathematical
Model
KOPT
OILENS
TSGPLUME
Computer Code
HSSM-KO
HSSM-KO
HSSM-T
[Section 1  Introduction]

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                                                Land Surface
                                KOPT
                                                   Vadose Zone
                                               NAPL
                                                     OILENS
                              Aqueous
                              Contamination
                                                     TSGPLUME
                                            Aquifer
Figure 3  HSSM schematic showing the use of each module
       The portion of the subsurface covered by each module of HSSM is shown in Figure 3.  In the
model scenario, the contamination is introduced as an LNAPL which flows from near the surface to the
water table. This portion of the contamination event is modeled by KOPT and OILENS,  as indicated on
the figure. Through contact with the infiltrating recharge and the groundwater, chemical constituents of the
NAPL dissolve and contaminate  the aquifer.  Transport  of one  chemical constituent of the NAPL  is
simulated by TSGPLUME.
                                                                        [Section 1 Introduction]

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1.3  Obtaining a Copy of HSSM

       HSSM is available from the Center for Subsurface Modeling Support (CSMoS) at the Robert S. Kerr
Environmental Research Laboratory (RSKERL).  CSMoS distributes software and documentation free-of-
charge through a diskette exchange program and provides technical support for the codes they distribute.
To obtain the HSSM software and user documentation send a letter of request along with two high density
3.5" formatted diskettes to the following address:

                            Center for Subsurface Modeling Support
                       Robert S. Kerr Environmental Research Laboratory
                         United States Environmental Protection Agency
                                       P.O. Box 1198
                                   Ada, Oklahoma 74820
                                     Voice: 405-436-8586
                                     FAX: 405-436-8529

Please indicate if the DOS or Windows version is needed.  If both interfaces are needed, enclose three
formatted diskettes.

       The complete HSSM package consists of the documents

a The Hydrocarbon Spill Screening Model (HSSM)  Volume 1: User's Guide,
a The Hydrocarbon Spill Screening Model (HSSM)  Volume 2: Theoretical Background and Source
       Codes,

and the two high density 3.5" diskettes.  The diskettes contain:
For Windows:

D diskette HSSM-1-w  The Windows Interface, HSSM-WIN


For DOS:

n diskette HSSM-1-d  The DOS Interface, HSSM-DOS


For Windows and DOS:

a diskette HSSM-2  Example Problems

HSSM and the user documentation are in the public domain. They may be freely distributed or copied by
anyone.
[Section 1 Introduction]

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Section 2   Assumptions  Underlying HSSM
       The following paragraphs discuss the conceptual basis of KOPT, OILENS and TSGPLUME. This
discussion is intended to give a clear understanding of the assumptions and limitations of each module of
HSSM.
2.1  Kinematic Oily Pollutant Transport (KOPT)

       The Kinematic Oily Pollutant Transport (KOPT) model simulates flow of the LNAPL phase and
transport of a chemical constituent of the LNAPL from the surface to the water table.   The LNAPL is
assumed to be released at or below the ground surface in sufficient quantity to form a fluid phase that is
distinct from the water. As a result, the amount of LNAPL released is far greater than that which would
give only contamination dissolved in the water  phase.  The flow system is  idealized as consisting of a
circular source region overlying a water table aquifer at specified depth.  Although the actual flow in the
vadose zone is three-dimensional, the KOPT model treats flow and transport through the vadose zone as
one-dimensional. Lateral spreading of contaminants by capillary forces is neglected, as is spreading due
to heterogeneity, since the soil is assumed to be of uniform composition.  For situations where the NAPL
is released over a  relatively large  area, the actual flow is nearly one-dimensional in the center.   For
contaminant sources that are of small areal extent, the lateral transport of contaminants may be significant.
By treating the flow as one-dimensional, however, the  modeling is conservative as all of the pollutant is
assumed to move downward and contribute to aquifer contamination. In actuality, some may be left behind
due to entrapment by layering or lateral  spreading.

       The spill of the LNAPL phase may be simulated in three ways (Figure 4):

       © The release of an LNAPL may occur at a known flux for a specified duration.  This situation
       would occur if a known volume of LNAPL was released during a certain time period.  The LNAPL
       volume divided by the duration and area of release determines the release rate, q0. If the LNAPL
       flux exceeds the maximum  effective  LNAPL conductivity, Keo,  some of the LNAPL will run off at
       the surface.

       © A known volume of LNAPL may be placed over a specified depth interval,  dp,.  When the
       simulation begins the LNAPL may begin to flow out of the specified zone, if the LNAPL retention
       capacity of the soil is exceeded.

       (D The last option is the specification of a constant depth of ponded LNAPL for a certain duration.
       This case represents a slowly leaking tank or a leaking tank within an embankment.  In either of
       these situations, the ponded depth of NAPL is estimated or known. Two options are available for
       this boundary condition. In  the first, the ponding abruptly goes to zero at the end of  the  ponding
       period. In the second,  the ponded depth decreases gradually at the end of the ponding period.
                                                      [Section 2 Assumptions Underlying HSSM]

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                                 uumii
                                                           - d..
                                 1. Flux Source Representation
                                 2. Volume Source Representation
                                3. Constant Head Source Representation
 Figure 4 HSSM release options
       LNAPL phase flow is assumed to occur within the soil which contains a uniform amount of water.
In KOPT, the amount of each fluid is expressed as saturation, S, which is defined as the fraction of the
pore space filled by a given fluid.  The water saturation corresponds to the average annual recharge rate
or a specified water saturation.  By using this approach, the temporal effects of climate are neglected.
Justification of this approach comes from the fact that in uniform soils the soil moisture profile shows little
variation except near the surface (Charbeneau and Asgian, 1991). Many data are required to simulate the
time record of rainfall events to develop the non-uniform and time-variable soil moisture profile. The level
of effort involved is not consistent with the intended purpose  of the model as a screening methodology.
Weaver (1991) presented model results which  illustrate the effects of rainfalls on in-place LNAPLs. This
work showed that when simulating fuels such as gasoline, the LNAPL often  reaches the water table rapidly.
So simulation of long sequences  of rainfalls may be of little  use,  if the objective of the modeling is to
estimate the gasoline's arrival time at the water table.

       In accordance with common soil science practice (Richards, 1931), the effect of the air flow on the
LNAPL phase transport is neglected in KOPT.  The presence of the water and air phases is incorporated
by the use of a  non-hysteretic, three-phase, relative permeability  model.  This model  is a reasonable
approximation of the pore-scale phenomena occurring in three-phase flow, but the actual nature of these
relationships is a major cause of uncertainty in this and most other multiphase flow models.  The model
uses measured properties of the  soil (capillary pressure curve parameters) to  approximate the relative
permeability.  The model does not include transport in fractures or macropores.
[Section 2 Assumptions Underlying HSSM]

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                                 Saturation
                         z,--
                     *
                                                    Sharp Front



                                                    Spreading Front
Figure 5  Comparison of sharp and spreading fronts
                                            Gasoline Transport

                                            in C125 sand, Rep.1
              f
              (D
              Q
                              50       100       150      200       250       300
Figure 6  Comparison between experimental data and the KOPT model
                                               g        [Section 2 Assumptions Underlying HSSM]

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       Efficiency is achieved in running the model primarily by neglecting the effects of the capillary
gradient on most aspects of the flow.  This causes the governing equations  to  become hyperbolic
equations, which can be solved  by the generalized method of characteristics (Charbeneau et al., 1994).
One major effect of this assumption on the simulation results is that the leading edge of the LNAPL moving
into the soil is idealized as a sharp front (Figure 5).  Some laboratory experiments in uniform sand packings
(Reible et al.,1990) show soil NAPL profiles which have nearly sharp fronts.    Similar results have been
found in flow visualization experiments conducted  in nearly uniform sands at the  Robert S. Kerr
Environmental Research Laboratory (RSKERL) and reported in Weaver et al. (1993).  Figure 6 shows an
experimental result for a gasoline release into a uniform sand.  Independently measured parameter values
were used to simulate the experiment.  It is clear that KOPT is able to simulate the main qualitative features
of the flow, because the shape of the simulated NAPL  front matches that of the experimental  data.
Quantitative agreement was obtained  by adjusting parameter values within their measured ranges. The
details of a similar experiment are presented in Volume 2 of the HSSM documentation (Charbeneau et al.,
1994).

       Since  the capillary gradient has a dramatic impact  on  the infiltration  capacity of the soil, the
approximate Green-Ampt model (Green and Ampt, 1911) is used to estimate the infiltration capacity during
the application of the LNAPL phase.  This gives an improved estimate of flux in the soil, given a flux or
constant head ponding condition at the surface.

       In KOPT and OILENS, the LNAPL is treated as a two-component mixture.  The LNAPL itself is
assumed to be soluble in water and sorbing. Due to the effects of the recharge water and contact with the
ground water,  the LNAPL may be dissolved.  This may be significant for highly soluble LNAPL phases.
The LNAPL's transport properties (density, viscosity, capillary pressure, relative permeability), however, are
assumed to be unchanging.  The  second component is the chemical constituent which can partition
between the LNAPL phase, water phase and the soil. This constituent of the LNAPL is considered the
primary contaminant of interest.  Concentrations of this constituent are reported in the model output and
graphed by the post-processors.

       A kinematic approach  is  used  by KOPT for transport of the chemical constituent, which results in
a model that neglects dispersion. The  chemical motion is assumed to be caused by the advection of water
and LNAPL only.  Hydrophobic  contaminants that reside primarily in the LNAPL phase will largely  be
transport with the LNAPL. The chemical constituent,  which is the second component of the LNAPL phase
discussed above, is assumed to partition between the NAPL, water and soil according to equilibrium, linear
partitioning relationships.  The constituent mass flux into the aquifer comes from recharge water that is
contaminated by contact with the lens and from dissolution that occurs as ground water flows under the
lens. The concentration  of the chemical in the aquifer is limited by its effective mixture solubility, which is
less than its pure phase solubility in water.
[Section 2 Assumptions Underlying HSSM]       10

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2.2  OILENS

       If a large enough volume of hydrocarbon is released, then the LNAPL reaches the water table.
Typically this occurs in a relatively short time for LNAPLs, like gasoiine, that have low viscosities. The
OILENS module simulates radial spreading of the LNAPL phase at the water table and dissolution of the
chemical constituent.  If sufficient head is available, the  water table is displaced  downward;  lateral
spreading begins; and the OILENS portion of the model is triggered.  OILENS is based on three major
approximations.  First, the LNAPL spreading is purely radial, which implies that the slope of the regional
ground water table is small enough to be unimportant for the lens motion.  Second,  the thickness  is
determined by buoyancy alone (Ghyben-Herzberg relations).  Third, the shape  of the lens is given  by the
Dupuit assumptions, where flow is assumed horizontal and the gradient is approximated by the change  in
head over a horizontal distance.  These three assumptions lead to an efficient formulation of the model,
which is reflected in its low computational requirements.

       The lens thickness in the formation and  the lens radius both increase  during the initial phase  of
spreading  (Figure 2).  The height of the lens depends on the LNAPL phase density and viscosity, the
release characteristics,  and the saturated hydraulic conductivity of the system.  For example, in a given
porous medium, diesel fuel would tend to form taller lenses than gasoline because of its higher viscosity.
Initially the lenses build up height because the  LNAPL enters the lens at a higher rate than it moves
radially.  Later, after the source rate declines, the lens thins while continuing to  spread laterally.  Residual
hydrocarbon is  left both above and below the actively spreading lens during this period  (Figure 7). The
thickness calculated by OILENS is an averaged  thickness of the LNAPL in the formation (Appendix 3.3,
Schwille, 1967) and  is not necessarily directly related to the thicknesses  observed  in observation wells
(Kemblowski and Chiang, 1990).
                                                                                 t+ At
 Figure 7 Lens configuration during thinning phase
                                              11
[Section 2 Assumptions Underlying HSSM]

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 Figure 8  Gaussian source configuration used in TSGPLUME
2.3  Transient Source Gaussian Plume Model (TSGPLUME)

       Aquifer transport of the chemical constituent is simulated by the Transient Source Gaussian Plume
Model (TSGPLUME) which uses a two-dimensional vertically averaged analytical solution of the advection-
dispersion equation.  Two important considerations are the boundary condition for the  aquifer and the
assumptions used in applying the two-dimensional planar model.

       The boundary conditions are placed at the down gradient edge of the lens and take the form of a
Gaussian concentration distribution with the peak directly down gradient of the center of the lens (Figure 8).
The peak concentration of the Gaussian distribution adjusts through time so that the simulated mass flux
from the lens equals that going into the aquifer.  The width of the Gaussian distribution remains constant
and is taken so that four standard deviations are equal to a representative diameter of the lens. Although
the size of the lens varies with time, a constant diameter is used in TSGPLUME for the aquifer source
condition.   A reasonable choice for the lens diameter  is the diameter that occurs when the mass flux into
the aquifer is a maximum.  This choice assures that  the peak mass flux into the  aquifer occurs through
an appropriately-sized lens.

       Although the aquifer model is two-dimensional  in the horizontal plane, complete mixing of the
chemical over the aquifer thickness is neither  necessary  nor assumed  a priori.   Vertical  mixing is
represented by the depth of penetration of the plume into the aquifer and is calculated from the amount
of vertical dispersion beneath the lens plus the advective flow due to infiltration through the lens, following
the approach  of Huyakorn et al. (1982). If the calculated penetration depth exceeds the aquifer thickness,
then the plume fully  penetrates the aquifer; and the model allows for dilution of the plume by diffuse
recharge.  If the penetration depth is less than the aquifer thickness, then the plume thickness is taken as
the penetration depth.  In the latter case, recharge simply pushes the plume deeper and  the penetration
thickness remains constant.
[Section 2 Assumptions Underlying HSSM]
12

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                              KOPT and OILENS Source Condition at Release Point
                              TSGPLUME Source Condition at Water Table
 Figure 9 Coordinate systems for the KOPT, OILENS and TSGPLUME Modules of HSSM
       Figure 9 shows the coordinate systems for all three modules of the HSSM model.  For KOPT and
OILENS, the source of contamination is assumed to be a circle of radius, Rs, located at the ground surface.
The coordinate origin is located at the center of the source. X is the down gradient direction, and Y is the
transverse horizontal direction. The Z axis points downward, so that the depth is equal to the Z coordinate
value.  In TSGPLUME, the source of contamination is assumed to be a circle of radius RT, located at the
water table. The size of the source is taken as a radius calculated in the OILENS module. The coordinate
origin (XT,YT) is assumed to be at the down gradient edge of the source of contamination.  The HSSM-T
implementation of TSGPLUME adjusts the X coordinates  used by HSSM-KO to the XT values needed by
TSGPLUME (XT = X - RT). The coordinates written in the output and plot files are the coordinates used
by KOPT and OILENS (X,Y,Z).

       In TSGPLUME, the water flow is assumed to be one-dimensional,  so advection of the contaminant
is  simulated only in  the  longitudinal  (XT) ground direction.   The constituent may be transported by
dispersion, however, both longitudinally (XT) and transversely (YT).  As with many analytical solutions, the
aquifer is assumed uniform.  The mass flux into the aquifer varies with time, and the concentration  history
at the receptor point is determined by integration of the constant input solution and the variable mass flux
distribution into the aquifer.
                                              13
[Section 2 Assumptions Underlying HSSM]

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                     I
                     I
                         ABC
                                         Time
Figure 10  Schematic representation of a TSGPLUME concentration history
       The results from TSGPLUME are concentration histories at user-specified receptor points.  At these
points, the model calculates the aqueous phase concentration of the contaminant beginning at the time at
which the concentration first rises above a threshold value (time A on Figure 10 ). This time is determined
by a search algorithm which uses the  analytical solution to determine  the earliest time at  which the
concentration is above the threshold.  Typically the threshold value is set to 1 ppb by the model  user.
Calculation of the receptor concentration continues at intervals of At, as set by the user.  The time interval
is shortened at time B to a small value in order to capture  the peak concentration.  If necessary,  the step
is further shortened in order to make sure that the peak is found. Once the concentration is reduced below
the peak (time C), the time step increases gradually to again equal the original  At.  Calculation continues
until the concentration drops below the threshold (time D).
[Section 2  Assumptions Underlying HSSM]
14

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Section 3   HSSM  Interface Options

       Two interfaces are provided to assist the user in  running the HSSM.  The first interface was
developed for the Microsoft Windows operating system. This interface consists of the windows interface
program, HSSM-WIN, and  the two simulation programs: HSSM-KO and HSSM-T. HSSM-WIN is used to
create and edit input data sets, execute HSSM-KO and HSSM-T, and plot the model results.  The windows
interface is described in Section 4, titled "The MS-Windows  Interface, HSSM-WIN."
                    Table 2  Comparison of MS-DOS and MS-Windows Interfaces
  Interface
Advantages
Disadvantages
  DOS
1.  The fastest performance of model
calculations is achieved (for any given
computer) under the DOS interface.

2. DOS interface can run on a
machine with limited processing power
and limited RAM. The code will
execute, albeit slowly, on a 286
machine with 640 kiloBytes of RAM.
1. The DOS preprocessor is
interactive but not graphical.
  Windows
1. A single shell program  performs all
necessary functions of the model.
                   2. Data are entered directly on
                   graphical screens.
                   3. Simultaneous display of all model
                   output.

                   4. Simultaneous display of output from
                   simulations with different parameter
                   values.

                   5. Ability to cut and paste to other
                   Windows applications.
1. The calculations performed by
HSSM-KO and HSSM-T are slower
under the Windows interface due to
Windows overhead.

2. Requires a machine with enough
processing power and memory to run
Windows effectively.  Typically this
would be a 386 or higher with at least
4 megaBytes of RAM.

3. Requires a certain level of
expertise with Windows.

4. More system memory is consumed
by Windows than  by DOS.
       The second interface was developed for the MS-DOS operating system. In this case the interface
consists of four programs:  PRE-HSSM, HSSM-KO, HSSM-T, and HSSM-PLT.  PRE-HSSM is used to
create and edit input data files; HSSM-KO and HSSM-T perform the model calculations, and HSSM-PLT
is used to plot and output the model results.  The four programs can be run individually or the HSSM-DOS
program can be used as a simple menu system. The DOS interface is described in Appendix 1 "The MS-
DOS Interface, HSSM-DOS."
                                            15
                                              [Section 3  Interface Options]

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       Each of the interfaces can be used to create and edit input data files, run the model, and plot the
results.  The Microsoft Windows interface allows extensive manipulation of the model output, concurrent
display of all of the main outputs of the model, and concurrent display of results from several simulations.
To aid in selecting a user interface, Table 2 describes some advantages and disadvantages  of each
interface. Detailed information on running the HSSM under each of the interfaces is given in the respective
section or appendix. Each contains the same information on  estimation of the model parameter values,
so that the  user has the parameter information available where its input procedures are described.

       Three utility programs are provided to simplify calculation of values of certain input parameters.
The utilities, which are listed in Table 3, are referenced as necessary where the parameter values are
described.   Background information and instructions for running the utilities are provided in appendices.
Table 3 HSSM Data Calculation Utilities
Parameter(s)
Soil Hydraulic Properties
Equilibrium NAPL/water partition coefficients
Average NAPL saturation for OILENS
Utility Program Name
SOPROP
RAOULT
NTHICK
3.1  Typographical Conventions

       The typographical conventions shown in Table 4 are used throughout the user's guide.
Table 4 Typographical Conventions
Type style
PROGRAM
new term
KEYBOARD
FILE.DAT
COMMAND
Use
Program names are written in capitals. For example:
HSSM-KO, and HSSM-T.
HSSM-WIN, HSSM-DOS,
Italic type usually signals a new term.
Small capitals are used to identify the names of keys
F1, or ESC.
on the keyboard like CTRL,
Filenames appear in this typeface. Specific references to the program files also
use this typeface, for example: HSSM-KO.EXE refers to the file which contains the
HSSM-KO program.
Commands entered at the DOS prompt and ASCII messages written to the
screen by DOS programs.
[Section 3  Interface Options]
16

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Section 4   The  MS-Windows Interface, HSSM-WIN
     The MS-Windows interface, HSSM-WIN, provides a convenient interface for creating and editing data
files, running HSSM, visualizing the output from several runs at one time, and exporting graphics into other
Windows applications.  This interface was developed from the ShowFlow Modeling Interface developed at
the University of Texas at Austin (Tauxe, 1990) and is described in this section of the user's guide.


4.1  Microsoft Windows Interface Overview

     The main functions of the interface are outlined in Table 5. Necessary details are provided in the
sections noted in the table.
Table 5 Outline of the HSSM-WIN Interface
Interface Function
1. Installation of HSSM-WIN
2. Operation of the HSSM-WIN Interface,
Summary of Interface Commands
3. Creation of Data Sets
4. Editing of Input Parameters
5. Running HSSM-KO and HSSM-T
6. Graphing HSSM Results
7. Interpretation of HSSM Graphs
8. HSSM Output File Contents
Section References
4.2 and 4
3
4.4
4.5
4.6.1 and
4.6.3 to 4.6
6
4.5.3, 4.7
4.5.4
4.8
6
     The general procedure for using HSSM-WIN follows. After installing HSSM-WIN, a data set must be
created by selecting the HSSM-WIN "Edit" menu item (Section 4.5). HSSM-WIN contains four data editing
screens (called dialog boxes) that are used in succession to create the complete input data sets for HSSM-
KO and HSSM-T (Sections 4.6.1 and 4.6.3 to 4.6.6). Once the user is satisfied with the data set, then the
data are saved to a new file name or an existing file may be overwritten.  This file name is loaded  into
HSSM-WIN's memory and will  be used when the simulation is performed.

     HSSM-KO and HSSM-T are executed from the Windows interface. Since HSSM-KO and HSSM-T
are independent programs, they must be run in succession to complete the entire simulation.  Section 4.7
describes the execution of these programs.  Once each has finished, a DOS window remains on screen
that the user must close before proceeding. This feature is provided because it is important to see the
screen messages that are  written by the programs.  (Windows would  normally close the DOS window
immediately upon completion of the programs and the user would not be  able to see  the final set of
messages.)
                                            17
[Section 4  The MS-Windows Interface]

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     When a simulation is completed, the results may be graphed with the HSSM-WIN Graph menu item.
Six graphs can be displayed by the interface, and the user may select those he/she would  like to view
(Section 4.5.4).   HSSM-WIN allows copying of graphs to other Windows  applications (Section 4.5.8),
simultaneous display of results from multiple simulations (Section 4.5.7), and printing of the graphs (Section
4.5.6).


4.2  System Requirements

     HSSM-WIN  is an application written for the Microsoft Windows graphical environment.   To use the
Windows interface the user should be generally familiar with personal computers, DOS, Windows, and the
HSSM model.  Users are advised to learn various features of Windows, as many of the capabilities of
HSSM-WIN require knowledge of Windows functions.  There are several requirements for your system:

HARDWARE:

     n   For 386 enhanced mode, a personal computer with the Intel 80386 processor (or  higher) and
         2 megabytes (MB) or more of memory (640K conventional memory and  at least 1024K of
         extended memory).

         For standard mode,  a personal computer with the Intel 80286 processor (or higher) and 1
         megabyte or more of memory (640K conventional memory and at least 256K extended memory).

         For real mode, a personal computer with the Intel 8086 or 8088 processor (or higher) and 640K
         conventional memory. Windows 3.1 and later do not support real mode.

     n   A hard disk and at least one floppy disk drive.

     a   A video monitor supported by Windows  (EGA or better resolution).

     n   A printer supported by Windows.

     n   A mouse that is supported by Windows  is strongly recommended.

     The amount of system memory available under Windows may be checked by opening a DOS window
and typing the DOS MEM command.  The amount of memory available for running a DOS application will
be displayed. This amount must exceed the approximately 400 kbytes required by HSSM-KO.  If sufficient
memory is not available under Windows,  HSSM-KO and HSSM-T may be run under DOS and the results
later plotted by HSSM-WIN.


SOFTWARE:

     n   Microsoft Windows version 3.0 or later.

     n   Windows requires MS-DOS or PC-DOS version 3.1  or later.
[Section 4 The MS-Windows Interface]          -\Q

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4.3  Installation

4.3.1  Packing List of Files
     Table 6 shows the files that are found on the HSSM-WIN distribution diskette, HSSM-1-w.
Table 6 Packing list of files for the HSSM Windows interface
File
HSSM-WIN.EXE
HSSM-KO.EXE
HSSM-T.EXE
HSSM-KO.PIF
HSSM-T.PIF
REBUILD.EXE
REBUILD.PIF
HSSMHELP.WRI
README.TXT
RAOULT.EXE
RAOULT.DAT
SOPROP.EXE
NTHICK.EXE
SYSTEM\COMMDLG.DLL
Purpose
The Windows interface program
The KOPT and OILENS modules of HSSM
The TSGPLUME module of HSSM
A Windows program information file (pif) for HSSM-KO.EXE
A Windows program information file (pif) for HSSM-T.EXE
A recovery program for interrupted simulations
A Windows program information file (pif) for REBUILD.EXE
The HSSM-WIN help file, which can be read by Windows WRITE (the
word processor bundled with Windows).
This file contains information on changes which have occurred since the
writing of the user's guide.
Utility to perform Raoult's Law Calculation
Default data set for the RAOULT utility
Utility to estimate soil properties with Rawls and Brakensiek's (1985)
regression equations.
Utility to estimate NAPL thickness at the water table
Windows dynamic link library provided for users of Windows 3.0
Several example problems, including those presented in Section 5, are distributed on diskette HSSM-2.
Be sure to back up these files on other diskettes and to write-protect the distribution diskettes.


4.3.2  Copying Files to the Hard Drive

     This section describes the installation of HSSM-WIN from DOS, which is the simplest  installation
procedure.  Check the README.TXT file for information on automated installation procedures which are under
development as of this writing.  Experienced users of Windows can install the program using Window's
File Manager.  For further information on File Manager, consult your Windows reference materials.

     After backing up the HSSM-1-w diskette,  create a sub-directory for the model by entering the DOS
                                              19
[Section 4  The MS-Windows Interface]

-------
command:

MKDIR C:\HSSM

where HSSM is the name of the HSSM-WIN subdirectory.  With the HSSM-1-w diskette in drive A, copy
all of the files from the diskette to the HSSM directory on the hard drive by entering:

COPY A:\*.*  C:\HSSM

(The HSSM-1-w diskette may be in another drive, say B, by entering "B:" rather than "A:" in the previous
command.) The example problems and output files contained on diskette HSSM-2 should be installed into
a separate directory.  Create the example problem directory by entering:

MKDIR C:\HSSM\EXAMPLE

The files are copied to this directory by entering:

COPY A:\*.*  C:\HSSM\EXAMPLE

Subdirectories can and should be created for each HSSM simulation.  For example, to create a directory
PROJECT1, enter the command:

MKDIR C:\HSSM\PROJECT1

By selecting the PROJECTI subdirectory when using HSSM, all the input and output files for the simulation
will be in c: \HSSM\PROJECTI.

     Users of Windows 3.0  will also need to  copy the dynamic link library COMMDLG.DLL from the
SYSTEM subdirectory on the distribution diskette to the SYSTEM subdirectory of their windows directory
on the hard disk by entering:

COPY A:\SYSTEM\COMMDLG.DLL C:\WINDOWS\SYSTEM

Windows 3.1 users already have this file. The  user will now likely wish to add HSSM-WIN to a program
manager group as described  in the next section.


4.3.3 Adding HSSM to a Program Manager Group

     The HSSM-WIN program should be added to a Program Manager group so that HSSM-WIN can be
executed by clicking on its icon.  Two procedures are  given for this operation:

® With both the File  Manager and Program Manager occupying different places on the screen  as in
Figure 11,  simply drag the file name  HSSM-WIN.EXE to the desired Program Manager group, where it will
appear as an icon.

© Alternatively, you may use the "File" "New" command of Windows to specify a new program group and
item.
[Section 4 The MS-Windows Interface]          20

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     For the program group:
     Select the Program Group radio button
     Click on the "OK" button
     Enter HSSM as the Description
     Click on the "OK" button
     For the program item:
     Select the Program Item radio button
     Click on the "OK" button
     Enter HSSM as the Description
     Enter c: \HSSM\HSSM-WIN.EXE as the Command line
     Enter c: \HSSM as the Working Directory
     Click on the "OK" button
  file  .DJsk  Tree  View  Options  Tools  Window
  Help
    -a NETWORK
    -DOLD_DOS.1
    -QQEMM
    -QROOT
               QX1STF.DAT
BHSSMHELP.WRI DX2BT.DAT
ilREADME.TXT   DX2TT.DAT
nREBUILD.EXE   QX2XT.DAT
QREBUILDPIF   DXYLENE.DAT
DTOLUENE.DAT
  [Selected 1 file(s) (123,680 bytes)
                 J [Total 16 file(s) (9
                                  File  Options  Y/indow  Help
                                                      Mam
                                                            Accessories
                                                                       Startup
JJ-
Figure 11  Installing HSSM-WIN in a Program Manager group

     Once HSSM-WIN has been successfully loaded onto your system, you must check the CONFIG.SYS
file.  The HSSM-KO program opens a number of temporary files and CONFIG.SYS must be configured so
that a sufficient number of files may be opened.  The CONFIG.SYS on your system needs to include the line

FILES =30

(A number greater than thirty will also work.) After modifying CONFIG.SYS you must reboot your system to
allow the change to take effect.  Installation of both the Windows and DOS interfaces on one computer
is discussed in Appendix 9.
                                             21
                                       [Section 4  The MS-Windows Interface]

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4.4  Using HSSM-WIN

4.4.1  Starting Up

     Like other Windows applications, HSSM-WIN will appear in a Program Manager group as an icon, and
can be started simply by double clicking with the mouse cursor on the icon.

     HSSM-WIN can also be started from Windows' File Manager by double-clicking on the file named
HSSM-WIN.EXE with the mouse pointer.  If you do not have a mouse, choose "Run..." from the "File" menu
(ALT+F followed by R) and enter "C:\HSSM\HSSM-WIN.EXE" in the prompt box. The screen will clear and
the main window of HSSM-WIN will appear.
                                                 Hydrocarbon Spill Screening Model
                                    file  £dit  Model firaph  Wjndow jjelp
     A variety  of  menu options
appears in the menu bar along the top
of the HSSM-WIN window (Figure 12).
These menu options are headings for
related operations which will appear in
a pull-down menu below each menu
item.  For more information on using
the  standard Windows interface
consult your Windows documentation.

     When HSSM-WIN first appears
on the screen, some menu items are
written in a different color, or disabled.
This means that those commands are
not available  at  this time, since no
data nor parameters have yet been loaded into the program. For example, the Save and Graph commands
are disabled since no data yet exist to save or graph.  The available options include File Open and Edit,
to open  an existing input file or edit one from  scratch.  Once data have been loaded, all of the menu
options become available.
                                   Figure 12 The initial HSSM-WIN screen
4.4.2  Menu Command Summary

     Table 7 contains a listing of all HSSM-WIN commands.  Every HSSM-WIN command is either

     ©  a menu option of the main menu bar (column headings 1 to 6 of Table 7, see Figure 12),
     ©  listed in a pull-down menu (entries in columns 1 to 6 of Table  7), or
     ®  listed in the system menu (entries in column 7 of Table 7).

(The system menu is accessed by clicking on the icon in the upper left corner of the window or by pressing
ALT + SPACEBAR on the keyboard).  Some of the commands are followed by an ellipsis (...), which means
that more information is requested before executing.  A menu item in HSSM-WIN may have one letter
underlined, or it may be followed by an accelerator (such as "Graph Results Ctrl+G").  These are shortcut
codes for the keyboard. The user who is familiar with the program may find that the keyboard is often
faster than the mouse.  A description of each command is presented in Section 4.10
[Section 4 The MS-Windows Interface]
                                             22

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Table 7 HSSM-WIN Command Summary

(a)
(b)
(c)
(d)
(e)
(f)
(g)
File
0)
New
Open...
Save
Save
as ...
/ Check
File times
Exit
HSSM-WIN

Edit
(2)
General
Data...
Hydrologic
Data...
Hydrocarbon
Phase
Data...
Model
Simulation
Data...



Model
(3)
Run
HSSM-KO
Run
HSSM-T
Run
REBUILD




Graph
(4)
Graph
Results...
Copy
Graph
Print
Graph
Close
Graph
Fonts


Window
(5)
Cascade
Tile
Arrange
Icons
Close All
(list of
graphs)


Help
(6)
Read Help
File
About
HSSM...
About
HSSM-WIN..




System
Menu
(7)
Restore
Size
Move
Minimize
Maximize
Close
Switch
to...
23
[Section 4 The MS-Windows Interface]

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 4.5  Use of HSSM-WIN Commands for Performing HSSM Simulations

     The following sections give the specific procedures for running HSSM Simulations using HSSM-WIN
 commands.   HSSM-WIN menu options are referred to by the column number and row letter in Table 7.
 For example, the Open option of menu bar item File is designated 1.b.


 4.5.1  Creating New Input Data  Sets

     © Clear any existing data and file names by selecting "New" from the "File" menu (1.a). This step
          can be skipped if no files have been used previously in the current HSSM-WIN session.

     © Call the Input File Editor by choosing "Edit" (2) from the HSSM-WIN menu (or use the accelerator
          Ctrl+E).

     ® Enter data in each of the four Input File Editors (2.a through 2.d) as  described in the Sections
          4.6.3 to 4.6.6,  and click on "OK" (ENTER) to exit the editor.

     ® Save the file with the "Save" command from the "File" menu (1.c).  When asked for a new  file
          name, enter a  name of up to eight characters.  There is no need to add the .DAT extension, as
          HSSM-WIN will do this.
4.5.2  Editing Existing Input Data Sets

     ©  Open an existing input file for editing by following the procedure given below:

          Choose the "Open..." option from the "File" menu (1 .b).  The Open Files dialog box will
          list the relevant file names in the default directory, as shown in Figure 13.
cz









3

File Name:
*.dat

benzene dat
sctl .dat
sct2.dat
sd1.dat
sd2.dat
shcl.dat
shc10.dat
shc2.dat
List Files of Type:
HSSM Data f DAT)






f.
T

i|











Open

[Directories:
c:\hssm

£3c\
fehssm
Drives:
me:









*|



I OK |

Ir~f*ni~ol I





          Figure 13  File Open dialog box
         Scroll through the list of names using the scroll bar with the mouse.
[Section 4 The MS-Windows Interface]
24

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         If the name of the desired file is listed here, double-click on the name to open it.  (With
         the keyboard, type the name in the box and choose ENTER to open the file. If you decide not
         to open a file, choose ESC to cancel.)
       Call the Input File Editor by choosing "Edit" (2) from the HSSM-WIN menu (or use the accelerator
         Ctrl+E).

        Enter data in each of the four Input File Editors (2.a through 2.d) as described in the Sections
         4.6.3 to 4.6.6, and click on "OK" (ENTER) to exit the editor.

        Save the file.

         n  If you want to overwrite the original file, simply  choose the "Save"  option from the "File"
              menu (1.c).
         n  If you want to select a new name with the "SaveAs" command from the  HSSM-WIN "File"
              menu (1.d).  When asked for a new file name, enter a name  of up to eight characters.
              There is no need to add the .DAT extension, as HSSM-WIN will do this.
            File Name:
c:\hssm\testdata.dat


4-
directories:

c:\hssm
                                                                     OK
                                       fc hssm
                                                                   Cancel
           Save File as Type:
Drives:
            HSSM Data (*.DAT)
         Figure 14  File Save As dialog box

4.5.3  Running the Model

    Choose "Model" (3) to perform the two parts of the HSSM calculations.

    ©  HSSM-KO is executed by selecting "Run  HSSM-KO " (3.a).  HSSM-KO reads the entire input
         data file and performs the KOPT and OILENS simulations. HSSM-KO then produces a separate
         input data file for HSSM-T, which contains some of the HSSM-KO input data and some of the
         HSSM-KO results that are needed by HSSM-T.

    ©  After the successful completion of HSSM-KO, the second step is to run HSSM-T, by selecting
         "Run HSSM-T" (3.b).  These two programs are DOS programs,  so Windows must create DOS
         processes in order to run these codes.  Section 4.7 shows the screen messages produced when
         HSSM-KO and HSSM-T are executed.
                                            25
                  [Section 4 The MS-Windows Interface]

-------
     NOTE:  If the parameters for TSGPLUME (HSSM-T) need to be changed after HSSM-KO has been
          executed, the data set must be edited and HSSM-KO must be run again.
4.5.4 Graphing the Model Results

     ® To generate graphs of the data, choose "Graph" (4) and "Graph Results..." (4.a) to get the Display
          Graphs dialog box (Figure 15).
                       Data file:
                       C:\HSSM\X2BT.DAT

                       Display graphs:

                       ^  Saturation Profiles

                       [X]  Oil Lens Profiles

                       K  Radius Histories

                       ^3  Contaminant Mass Flux

                       [X]  Contaminant Mass in Lens

                       O  Receptor Well Concentrations
                   Figure 15  Display Graphs dialog box


     ®  Choose which graphs to make by clicking on the check boxes.  An "X" in the box means that it
          has been selected. To do this from the keyboard, press the TAB key to move the highlight to the
          desired checkbox and SPACEBAR to turn the check on or off.

     d)  Choose "OK"  to draw the graphs.

     ®  To close a graph, choose "Close" from the graph window's system menu, or (4.d) double-click with
          the mouse on the system menu  icon in the upper left corner of the graph window.  Closing
          unneeded graphs makes more room in memory for other graphs or programs.
4.5.5  Graphing Results From a Previous Simulation

     ©   Load the data set by selecting "Open" from the "File" menu (1.b).

     ®   To generate graphs of the data, choose "Graph"  (4) and "Graph Results..."  (4.a) to get the
              graph dialog box.

     ®  Choose which graphs to make by clicking on the check boxes.  An "X"  in the  box means that
          it has been selected.   To do this from the keyboard, press the TAB key to  move the high-
          light to the desired checkbox and SPACEBAR to turn the check on or off.

     ®  Choose "OK" to draw the graphs.
[Section 4  The MS-Windows Interface]
26

-------
     ©  To close a graph, choose "Close" from the graph window's system menu, or (4.d) double-click
          with the mouse on the system menu icon in the upper left corner of the graph window.  Closing
          unneeded graphs makes more room in memory for other graphs or programs.

4.5.6  Printing a Graph

     ©  Generate a graph as described above.

     (D  From the "Graph" menu, choose the "Print Graph" (4.c) option.

     ©  After a few seconds, a message reading "Sending graph to print manager" will appear, with the
          option to cancel the print job.  Unless the job is to be canceled, wait until the message dis-
          appears.  This means that the image has been sent on  its way, and HSSM-WIN is ready  to
          continue.

     NOTE: Small graphs will print relatively quickly, but larger images will take longer. A full-page graph
          may take several minutes, depending on the sophistication of the printer and printer driver soft-
          ware and on availability of free memory and hard disk space.


4.5.7  Comparing Several Simulations

     ©  Edit  or create an input  file, run the simulation, and graph the  results.  If the simulations have
          already been run  and  the plot files exist, then load the file name with "Open" and "File"  (1.b),
          and choose the "Graph" command to display the graphs (4.a). Using the Minimize command,
          reduce each of the graphs to an icon.  The icons will be displayed along the bottom of the
          HSSM-WIN window.  Do this for the simulations you wish to compare.

     ©  Restore the graphs which you wish to compare by either double-clicking on the icon or selecting
          from the graphs listed in the "Window" pull-down menu (5.e). You may choose as many graphs
          as you wish.

     ©  Use the "Tile" command under the "Window" menu (5.b) to redraw the graphs as in Figure 16.

     ®  If you desire, the graph windows may be resized to match scales  by "dragging" the corners  or
          sides with  the  mouse or by  using the Move  and Size commands  from the graph window's
          system menu (7.cand 7.d).

     © To view the parameter values for a particular run, open the file in  question and view the data using
          the Input File Editors (2.a through 2.d).
                                             27           [Section 4 The MS-Windows Interface]

-------
                                       HSSM-WIN-X2BT
        file  £dit  Model   Graph  Window
                      x2bt-SAT
                      Saturation Profiles
         Benzene transport from 1500 gal gasoline spill
         0.00  Depth (m)
                                      1 0000 d
                                      5.0000 d
                                      10000d
                                      75 000 d
                                      100 00 d
                                      12500d
                                      150.00 d
                                      200 00 d
           0.00   0.20   0.40   0.60   0.00
          	Total liquid saturation
1.00
                  benzene - SAT
                    Saturation Profiles
       BENZENE contamination from Gasoline
             Depth (m)
       1.00

       2.00

       3.00

       4.00

       5.00
                            1 0000d
                            2 0000 d
                            50000d
                            10000d
                            25.000 d
                            50 000 d
                            100.00 d
                            15000d
                            200 00 d
                            300.00 d
 o.oo   0.20   p.40    o.eo   o.oo
	Total liquid saturation	
                                         1 00
                                                  FLUX
        benzene-LENS  benzene-RADII benzene-MASS  benzene-FLUX   x2bt-LENS
                                                                        xZbt-RADII
     Figure 16  Comparison of Graphs from Two Different Simulations
     NOTE:  Each graph on the screen consumes up to a few KB of memory which are freed on closing
          the graph window.  With  several graphs  and/or other applications  running, HSSM-WIN  or
          Windows may determine that there is not enough free memory or resources to create another
          graph.   In this case, the user will be asked to terminate something  to create more room in
          memory.
4.5.8  Copying a Graph to the Clipboard

     Windows programs have the ability to transfer screen images directly from one Windows application
to another.  For example, an HSSM-WIN  graph can  be copied into  a word processor document.  The
Windows Clipboard is used as an intermediate storage point for such  transfers.

     © Generate  a graph as described above.

     ® From the "Graph" menu (4), choose the "Copy Graph" option (4.b).  This copies the graph to the
          Clipboard in a bitmapped format and replaces any previous Clipboard data.

     ® To see the contents of  the Clipboard at any time, run the Clipboard program.

     © To paste the graph into another application, find the "Paste" command in that application's menu,
          if available. It should be listed under the "Edit" pull-down menu.  Figure 17  shows an HSSM-
          WIN graph  pasted into PAINTBRUSH.
[Section 4  The MS-Windows Interface]
    28

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     ® Bitmaps copied to the Clipboard can be saved as *.CLP files as well, so that graphs may be kept
          for later use.
        Edit  View  Text   Pick  Options   Jdelp
                                       Saturation Profiles
           Benzene transport from 1500 gal gasoline spill
            rj oo  Depth (m)
                                                                       25.000 d
                                                                       50.000 d
                                                                       75.000 d
                                                                       100.00 d
                                                                       125.00 d
                                                                       150.00 d
                                                                       200.00 d
                 % saturation ///,
                                       0.10         0.60
                                    Total liquid saturation
Figure 17  HSSM-WIN graph pasted into PAINTBRUSH
4.5.9 Exiting HSSM-WIN

     HSSM-Win can be exited by selecting the "File" and "Exit HSSM-WIN" (1.f). The program may also
          be exited by double-clicking on the system menu in the upper left corner (equivalent to selecting
          7.f).  If any work has not been saved, HSSM-WIN will alert the user  to save it before the
          program closes down.
4.6  Editing and Creating HSSM Data Sets
     The following sections describe all the required parameters for HSSM.  The sections also provide
guidance on how to determine appropriate values of the parameters.  For convenience, blank templates
of each of these screens are provided in Appendix 13. These templates are useful for assembling data
sets and may be copied for repeated use.  Experienced users of the model may wish to edit their data sets
directly; Appendix  10 shows the structure of the HSSM-KO and HSSM-T input data files.
                                              29
[Section 4 The MS-Windows Interface]

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4.6.1  Using the Input File Editors - Common Techniques

     The following are instructions for using the Editor for the input data screens (called dialog boxes).
Each of the dialog boxes requires the usage of the features described below.
     ©  The Input File Editor dialog boxes are HSSM-WIN's method of editing the input file for the models.
          They are displayed by choosing the "Edit" and one of the data options from HSSM-WIN's menu.
          This section discusses general techniques for navigating around and editing data in these dialog
          boxes, that are illustrated in Figure 19 to Figure 22.

     ®  Standard Windows methods for selecting and editing text are adopted by HSSM-WIN:

          To select an entire word or numeric entry, simply double-click on the entry with the mouse or
          drag the mouse (holding down the button) across the desired selection. Selected text appears
          in reverse video. Any typing done now  will replace the selected text. If  you  do not want to
          replace the text but rather  edit it, use the mouse or the arrow keys to position the cursor in the
          box.  The DELETE key will delete to the right of the cursor, and the BACKSPACE key to the left.

     ®  Move to the other text fields beside each parameter description with either the mouse or the TAB
          key.  (To  move backwards, use SHIFT + TAB.)  Edit the contents of each window as desired.

     ®  Radio buttons O are used to choose among mutually exclusive options which appear in various
          dialog boxes.  Depending  on the choice made, some entry fields may be disabled or enabled
          as appropriate. Radio buttons are chosen by either clicking with the mouse, or using the t and
          I keys to move and the SPACEBAR to select.

     ©  Check boxes D are used to enable or disable non-exclusive options.  These are also selected with
          the SPACEBAR.
        Accept the new values by choosing the "OK"
          pushbutton  (ENTER).   "Cancel"  (ESC) will
          abandon any changes made.
                                                                ShowHow
                                                            Number must be between 0.0 and 1.0
                                                   Figure 18 An example of a data entry error
                                                   message
     The Hydrologic Parameters,  Hydrocarbon
     Phase  Parameters  and  Simulation
     Parameters dialog boxes contain a check
     box titled "Enable range  checking."  This
     box is normally checked and causes HSSM-
     WIN to check each parameter to assure that
     it is within allowable limits. Each field will be tested for illegal characters or out-of-range values,
     in which case an error message will appear as in Figure 18. After acknowledging this message
     with "OK," the user will have the  opportunity to edit  the offending field where HSSM-WIN has
     moved the prompt. Disabling the range checking option causes HSSM-WIN not to check the
     parameter values.

© After exiting the editing dialog box, the changes are in HSSM-WIN's memory, but they are not yet
     saved to a file. Use the "Save" or "SaveAs" commands to save them.

NOTE: To view the  underlying graphs while assigning values to the parameters, the Editing window
     (like any other) can be almost entirely moved off the screen by dragging its title bar.
[Section 4  The MS-Windows Interface]
                                         30

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4.6.2 Required Units for HSSM Simulations
     The following units are used in HSSM and are listed with their usage and abbreviation. Care must
be taken to assure that all input parameters are converted to this set of units. As a reminder, the required
units are listed with  each parameter discussed below.
Table 8 Required Units for HSSM Simulations
Quantity
Time
Depth
Dynamic Viscosity
Density
Surface Tension
Concentration
Soil-Water Partition
Coefficient
Dispersivity
Various
Unit
day
meter
centipoise
grams/cubic centimeter
dyne/centimeter
milligrams/liter
liters/kilogram
meters
dimensionless
4.6.3  General Model Parameters

          The General Parameters  dialog box (Figure 19) contains titles,  printing switches, module
          switches, and file names.
     Run Titles

          A three-line run title is used by HSSM-WIN.  These text strings are included in all of the output
          and plot files. The first line is also used as a graph title.   If the graph is too  small to plot, the
          graph window contains  only the three title lines.

     Printing switches

          D Create output files
               If this switch is chosen, output files will be generated by the models. The normal situation
               is to choose this option.
                                               31
[Section 4  The MS-Windows Interface]

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                                  General Model Par,
   Run Titles:
   Benzene transport from 1500 gal gasoline spill
    1.15% benzene in gasoline
    sandy soil, properties from Carsel and Parrish
   "Printing switches	
     [>3 Create output files
     O Echo print data only
     (8) Run models
                  'Module switches
                    E3 Run KOPT
                    [X] Run OILENS
                    1E1 Write HSSM-T input file
   'File names'
     C:\HSSM\X2BT.DAT
     C:\HSSM\X2BT.HSS
     C:\HSSM\X2BT.PL1
     C:\HSSM\X2BT.PL2
     C:\HSSM\X2BT.PL3
     C:\HSSM\X2BT.PMI
     C:\HSSM\X2BT.TSG
     C:\HSSM\X2BT.PMP
 NOTE: These filenames will be used if the data file
is saved under a new name with the "SaveAs" option.

                          HSSM-KO input file
                          HSSM-KO output file
                          HSSM-KO plot file 1
                          HSSM-KO plot file 2
                          HSSM-KO plot file 3
                          HSSM-T input file
                          HSSM-T output file
                          HSSM-T plot file
                                                  Cancel
Figure 19  General Parameters dialog box
         O Echo print data only
         O Run Models
              This switch tells the model either to run and create plot files, or only to echo the input data.
              Echo printing, to check the input file, is recommended before making the simulation run.

     Module switches

         D Run KOPT

              Run the KOPT module of HSSM-KO. KOPT simulates the infiltration of the NAPL through
              the vadose zone.  KOPT must be run in order to run OILENS or TSGPLUME.

         D Run OILENS

              Run the OILENS  module  of HSSM-KO, to simulate the motion and dissolution  of the
              hydrocarbon lens at the water table. OILENS requires that KOPT also be run.
[Section 4 The MS-Windows Interface]
                32

-------
          D Write TSGPLUME input file

               Write the TSGPLUME (HSSM-T) input data file when the HSSM-KO program is run.
               This option must be selected if HSSM-T is to be run.   HSSM-T, which simulates
               transport of the chemical constituent in the aquifer,  is run using the "Run HSSM-T"
               command, only after HSSM-KO has run.
     File names
          HSSM requires the use of a specific set of files for producing output and plot files. These names
          can not be edited, but are included for the user's information as they will appear in the indicated
          directory after running  the model. The names change automatically whenever the file is saved
          under a new name.  The names and purposes of the files are listed in section 4.7.
4.6.4  Hydrologic and Hydraulic Data

          The Hydrologic Parameters dialog box (Figure 20) lists hydrologic and hydraulic data for the
          model.
                                        Hydrolocjic Par,
             HYDROLOGIC PROPERTIES
   Water dynamic viscosity (cp).
   Water density (g/cm*)	
   Water surf, tension (dyne/cm)
   Maximum krw during infiltration
Data file:
C:\HSSM\X2BT.DAT
Q Enable range checking
| Cancel   \
   ~£apillary pressure curve model
    O Brooks and Corey
    ® van Genuchten

    Brooks and Corey's lambda
    Air entry head (m)	
    Residual water saturation
    van Genuchten's alpha (1 /m)
    van Genuchten's n	2.680
         POROUS MEDIUM PROPERTIES

Sat'd vert, hydraulic cond. (m/d)
Ratio of horz/vert hyd. cond
Porosity	
Bulk density (g/cm*)	
Aquifer saturated thickness (m)
Depth to water table (m)	
Capillary thickness parameter (m)
Groundwater gradient (m/m)	
Longitudinal dispersivity (m)	
Transverse dispersivity (m)	
Vertical dispersivity (m)	  .1000
Figure 20  Hydrologic Parameters dialog box
                                              33
         [Section 4  The MS-Windows Interface]

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     HYDROLOGIC PROPERTIES

     Water dynamic viscosity, |jw (cp)

          Enter the dynamic viscosity of water in centipoise (cp). At 20°C the viscosity of pure water is
          1.0 cp.

     Water density, pw (g/cm3)

          Enter the density of water in g/cm3. At 20°C the density of pure water is 1 g/cm3.

     Water surface tension, aaw (dyne/cm)

          Enter the water/air surface tension in dyne/cm. At 20°C the surface tension of pure water is 72.8
          dyne/cm.  A lower value, say 65 dyne/cm, may be appropriate for soils and/or contaminated
          sites.

     Maximum relative permeability to water, k^^,,,,, during infiltration

          Enter the maximum water relative permeability during infiltration.  Since air is normally trapped
          during infiltration, the effective hydraulic conductivity of the soil will  be less than the saturated
          conductivity.  The relationship between effective conductivity  to water, Kew,  and saturated
          conductivity to water, Ksw  is given by

                                       '      =  Kkw                                   (1)
          where kTO is called the relative permeability to water.  The relative permeability equals zero
          when the saturation is at or below residual, and equals one when the porous medium is
          completely saturated with water.

          To account for trapping of the air phase, the maximum effective conductivity is restricted
          by the value set for k^,^,.   Typical values range from 0.4 to 0.6 (Bouwer  1966); 0.5 is
          often used (e.g., Brakensiek et al., 1981).   The  maximum  water saturation  is then
          determined from the kTO function that is used by HSSM. The remainder of the pore space
          is assumed to be filled with trapped air. The water saturation calculated from k^,,,^ is then
          discarded, as only the trapped air saturation is used by the model.


     Recharge

          Check the type of recharge condition desired.  Recharge can as either by specifying a recharge
          rate or as a vadose zone residual water saturation.

          O Average annual  recharge rate, qw (m/d)

               Choose this option to specify a recharge flux.

          O Saturation, S^,

               Choose this option to specify a constant water  saturation in the pore space.

[Section 4  The MS-Windows Interface]           34

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          When annual recharge is chosen for the recharge input:

          The value entered is the  average annual  recharge rate.  For example, with an annual
          recharge rate of 10 cm/yr the value entered is:
                  2.74 x10-4      =  10  «2  -^-l \^L.\                  (2)
          HSSM-KO calculates the water saturation (fraction of the pore space that is
          filled with water) from the recharge rate. Large recharge rates may cause the
          available pore space to be completely filled with water, allowing no NAPL to
          infiltrate.  If such conditions are encountered an error message is written to the
          screen.
          When saturation is chosen for the recharge input:

          If 35% of the pore space is filled by water, then 0.35 is entered here.  Using the
          other set of units: if the volumetric moisture content is 0.14 and the porosity is
          0.40, then the equivalent saturation of 0.35 is entered here.

          Typically the moisture content at or above the field capacity would be used here,
          after converting to saturation. The relationship between volumetric moisture
          content,  9W, porosity, r\, and saturation, Sw, is given  by 0W = r|Sw.   From the
          saturation input, HSSM-KO calculates the associated water flux.

Capillary Pressure  Curve  Model

     O Brooks and Corey
     O van Genuchten

     Choose the capillary pressure model to be used in HSSM calculations.  Further information on
     the selection of the model parameters is given in Appendix 3.1  "Soil Properties."   Either Brooks
     and Corey or  van Genuchten model parameters may be used.  The appendix contains typical
     parameter values for each of these models. Although the HSSM is designed to use the Brooks
     and Corey model, van Genuchten model parameters may  be entered as input. The van
     Genuchten model parameters are converted to approximately  equivalent Brooks and Corey
     model parameters by a procedure developed by Lenhard et al. (1989).   Only the parameters
     highlighted for the chosen model need be entered.
                                         35           [Section 4  The MS-Windows Interface]

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          For the Brooks and Corey Model:

          The  Brooks and Corey (1964)  model equation which describes the relationship
          between saturation Sw and capillary head hc is given by
                                                  V
          where the residual water saturation, Swr, the air entry head, hce, and the pore size distribution
          index, A,, are fitting parameters.
          Brooks & Corey's A,

          The parameter A, is called the pore size distribution index, and is determined by either fitting the
          Brooks and Corey model to the water/air capillary pressure curve PC(SW) by a procedure outlined
          by Brooks and Corey (1964), or by non-linear curve fitting (e.g., van Genuchten et al., 1991).

          Brooks & Corey's Air entry head, h^ (m)

          Enter the  absolute value of the  air  entry head  in meters.  This value is  determined as a
          parameter from the water/air capillary pressure  curve  (see item  on Brooks and Corey's  A,,
          above.)

          Residual water saturation, Sw

          Enter the residual water saturation, which is determined from the measured capillary pressure
          curve (see item on Brooks  and Corey's A, above.)

          For the van Genuchten Model:

          NOTE:  selecting  the van Genuchten  model causes HSSM to  calculate  approximately
               equivalent Brooks and Corey model parameters as described  in Appendix 4.

          van Genuchten's model is defined by
                                                      (« hcr]m
          where
               0W   = volumetric water content
               hc   = capillary head with units of m
               0wr  = volumetric residual water content
               6m   = volumetric maximum water content

[Section 4  The MS-Windows Interface]          35

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              a   = a parameter with units of m'1
              n    = a parameter
              m   = a parameter (taken as a simple function of n)

          For HSSM the reduced water content term (the left hand side of van Genuchten's model)
          is taken to be equal to

                                          o  _  o
                                                 ^
         where the maximum water saturation,  Om, has been equated with  the porosity.  The
         parameters of van Genuchten's model can be fitted to measured data by using a fitting
         program like RETC (van Genuchten et al., 1991).

         Residual water saturation, Sm

         Enter the residual water saturation, which is determined from the measured capillary pressure
         curve.

         van Genuchten's a

         Enter the value of van Genuchten's parameter a in units of m"1.

         van Genuchten's n

         Enter the value of van Genuchten's parameter n.
POROUS MEDIUM PROPERTIES

     Saturated vertical hydraulic conductivity, K, (m/d)

         Enter the value of the saturated vertical water phase hydraulic conductivity, Ks, in meters per
         day.  Saturated hydraulic conductivity is one of the most important parameters of the model.
         Estimation  of this parameter is described in  Appendix 3.1 "Soil Properties."  This appendix
         contains data from two tabulations of soil properties.
                                             37           [Section 4 The MS-Windows Interface]

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     Ratio of horizontal to vertical hydraulic conductivity

          Enter the ratio of the horizontal saturated water phase conductivity to the saturated vertical water
          phase hydraulic conductivity.  Anisotropy is not treated directly in HSSM, rather the model uses
          the product of the ratio RKS and the saturated  vertical conductivity, Ks,  to  determine  the
          hydraulic conductivity of the aquifer.  This later conductivity is also  used for determining the
          effective  conductivity  to the  NAPL for  the lens spreading.  The relationships between  the
          conductivities are summarized in Table 9.
Table 9 Summary of Hydraulic Conductivity Relationships
Model and Region
Vadose zone (KOPT)
NAPL lens (OILENS)
Aquifer (TSGPLUME)
Hydraulic Conductivity
Used
Vertical
Horizontal
Horizontal
HSSM Variables
Ks
KS*RKS
KS*RKS
     Porosity, r|

          Enter the porosity, T\, of the aquifer.

     Bulk density, pb (g/cm3)

          Enter the bulk density of the soil in g/cm3.  Porosity, r|, and bulk density, pb are related by


                                       Pa   =  P.(1  - TI)                                  (6)

          where ps is the solids density.  The density of quartz is approximately 2.65 g/cm3.  The
          values for porosity and bulk density must be related by equation (6).


     Aquifer saturated thickness (m)

          Enter the saturated thickness of the aquifer in meters.

     Depth to water table (m)

          Enter the depth to the water table from the release point in meters. The release point is usually
          at the ground surface.
[Section 4  The MS-Windows Interface]
38

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Capillary thickness parameter (m)

     The capillary thickness parameter gives the model  a thickness which must build  up in the
     capillary fringe before spreading of the NAPL occurs.  Typically, a value of 0.01m should be
     entered for this parameter.  This results in a small thickness of NAPL that is built up before
     spreading begins.

     The capillary thickness parameter can also be used to incorporate  the effect of water table
     fluctuation on the lens radius.  Water table fluctuation can cause trapping of NAPL throughout
     a smear  zone, and the trapped  NAPL is  not available for radial spreading.  To include this
     effect, the capillary thickness parameter should be calculated by
      f capillary'
       thickness
smear zone thickness x residual NAPL saturation      (7)
      [parameter)                 maximum NAPL saturation in lens
     The smear zone thickness should be taken as the maximum water table fluctuation.   The
     residual NAPL saturation and maximum  NAPL saturation in the lens  are described under the
     Hydrocarbon Phase Data dialog box (Section 4.6.5).
Ground water gradient (m/m)

     Enter the ground water gradient.  Typical maximum natural gradients range from 0.005 to 0.02.
     Since pumping wells are not allowed in TSGPLUME, natural gradients should be used here.

Aquifer Dispersivities AL, AT, Av (m):  Longitudinal, Horizontal Transverse, Vertical Transverse.

     Enter the longitudinal,  horizontal transverse and vertical transverse dispersivities in  meters.
     The dispersivities are defined by


                                    DL  =  AL  v
                                    DT  =  ATv                                    (8)

                                    Dv  =  Avv
     where DL, DT, and  Dv are the longitudinal,  horizontal transverse,  and vertical transverse
     dispersion coefficients; AL, AT, and Av are likewise the longitudinal, horizontal transverse, and
     vertical transverse dispersivities; and v is the seepage velocity in the mean flow direction.

     Dispersive mixing in aquifers results from solute transport through heterogeneous porous media.
     As the contaminant plume spreads it  "experiences" more  heterogeneity  and  the  apparent
     dispersion coefficient increases.  Thus the dispersion coefficients, DL, DT and  Dv are not
     fundamental parameters, but exhibit scale dependence.
                                         39           [Section 4 The MS-Windows Interface]

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          Gelhar et al. (1992) recently reviewed dispersivities determined at 59 sites and considered the
          reliability of the dispersion coefficients.  They concluded that  there are  no highly  reliable
          longitudinal dispersion coefficients at scales greater than 300m.  Notably, at a given scale,
          dispersivities have been found to vary by 2 to 3 orders of magnitude, although the lower values
          are more reliable.  Based on these data, horizontal transverse dispersivities are typically from
          1/3 to almost 3 orders-of-magnitude lower than longitudinal dispersivities.  Vertical transverse
          dispersivities are typically (although based on a very limited data set) 1-2 orders-of-magnitude
          lower than horizontal transverse dispersivities.  The very low values of vertical  transverse
          dispersivities reflect ro'ughly horizontal stratification of sedimentary materials.
4.6.5  Hydrocarbon (NAPL) Phase Data

          The Hydrocarbon (NAPL) Phase Parameters dialog box (Figure 21) contains data concerning
          the nature of the spilled hydrocarbon and one constituent of interest.
                                    llydroc.
         HYDROCARBON PHASE PROPERTIES

   NAPL density (g/cm*)	
   NAPL dynamic viscosity (cp)
   Hydrocarbon solubility (mg/L)
   Aquifer residual NAPL saturation
   Vadose zone residual NAPL sat'n
   Soil/water partition coeff. (L/kg)
   NAPL surface tension (dyne/cm)

        DISSOLVED CONSTITUENT PROPERTIES

   [X] Dissolved constituent exists
   Initial constit. cone, in NAPL (mg/L).
   NAPL/water partition coefficient....
   Soil/water partition coeff. (L/kg)...
   Constituent solubility (mg/L)	
   D C_onstit. 14-life in aquifer (d)	
      so Par.imolers




	
ition. . . .
sat'n. . .
kg) ....
cm) 	
.7200
4500

10 00

.1500
5000E-01
8300E-01
35.00
    Data file:
    C:\HSSM\X2BT.DAT
    O Enable range checking
|  Cancel   |
      HYDROCARBON RELEASE	
       (•) Specified flux
       O Specified volume/area
       O Constant head ponding
       O Variable ponding after const head period

       NAPL flux (m/d)..
       Beginning time (d)
       Ending time (d)
       Ponding depth (m)
       NAPL volume/area (m)
       Lower depth of NAPL zone (m)
Figure 21  Hydrocarbon Phase Parameters dialog box


     HYDROCARBON PHASE PROPERTIES

     NAPL density, p0 (g/cm3)

          Enter the NAPL phase density in g/cm3.  For OILENS simulations, the NAPL density must be
          less than that of water.  Densities greater than water may be used if no OILENS simulation is
          performed.  Some typical NAPL densities are given in Table  10.
[Section 4  The MS-Windows Interface]
40

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     Hydrocarbon densities are sometimes expressed by the degrees API (Perry and Chilton, 1973)
     scale adopted by the American Petroleum Institute.  Degrees API is defined by
                            MP/   =
141.5
sp.gr.
- 131.5
(9)
     where sp.gr. is the specific of the NAPL measured at 70° F divided by the specific gravity of
     water measured at 60° F.  The degrees API scale runs from 0.0 to 100.0 and covers a range
     of specific gravities from  1.076 to 0.6112.

NAPL dynamic viscosity, |j0 (cp)

     Enter the NAPL phase viscosity in centipoise.  Typical NAPL viscosities are given in Table  10.

     The densities and viscosities of the NAPL and water phases are used by HSSM-KO to estimate
     the saturated hydraulic conductivity to the NAPL phase, Kso, by


                                 Ken  =  i\~.u — —                          U")
                                                   w
     where Ksw is the saturated hydraulic conductivity to water, uw and |J0 are the water and oil
     viscosities, and pw and p0 are the respective densities.
Table 10 NAPL Densities and Viscosities at 20°C
Liquid
Methylene Chloride
TCE
PCE
Gasoline
Carbon Tetrachloride
Water
No. 2 Fuel Oil
Transmission Fluid
Aroclor 1254
Density
g/cmg
1.33
1.47
1.60
0.75
1.59
1.00
0.87
0.89
1.51
Viscosity
Cp
0.426
0.566
0.900
0.45
0.970
1.00
5.9
80
2050
                                         41
             [Section 4 The MS-Windows Interface]

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     Hydrocarbon (NAPL) solubility (mg/L)

          Enter the NAPL water solubility in mg/L.  This coefficient represents the solubility of all of the
          NAPL constituents,  except the chemical constituent that is simulated.  The solubility of the
          chemical  constituent is entered separately.  Further, this value is only  used by the model in a
          substantial way if one particular  ending criterion is used.  Therefore  the value of the NAPL
          solubility is not a critical parameter.

          The value of NAPL solubility must be greater than zero if the OILENS Simulation ending criterion
          (see below) is set to © "NAPL lens spreading stops."  Bauman (1989) estimated that the typical
          solubility of gasoline is on the order of  50 to 200 mg/L.

     Aquifer residual NAPL saturation, Sore

          Enter the residual NAPL phase saturation in the aquifer.  See notes below for the vadose zone
          residual NAPL saturation.

     Vadose zone residual NAPL saturation, Son

          Enter the residual NAPL phase saturation for the vadose zone. By definition, the NAPL phase
          does not  flow at saturations less than or equal to residual.   In this model,  the residual NAPL
          saturation is assumed to be a known constant. Ideally, this would be obtained by measuring
          the NAPL/air capillary pressure curve in the presence of the amount of water filling a portion of
          the pore space.  Treating the residual NAPL saturation as a constant is acknowledged to be an
          assumption,  as  in actuality the NAPL  residual  saturation may vary with the hydraulic gradient
          and with time as the NAPL weathers (Wilson and Conrad, 1984.)  Typically the residual NAPL
          saturation in the vadose zone is less than that for the aquifer (with the same media properties).
          Typical hydrocarbon residual saturations vary from 0.10 to 0.20 in the  vadose  zone, and  from
          0.15 to 0.50 in the saturated zone (Mercer and Cohen, 1990). These values correspond more
          closely to "specific retention", as the term is used in ground water hydrology, rather than true
          residuals  at  large capillary pressure values.

     Soil/water partition coefficient (L/kg)

          Enter the linear equilibrium  partitioning  coefficient between the soil and the  water phase
          concentrations (cs and cj of the hydrocarbon phase. Like the solubility of the NAPL phase,
          listed above, this parameter is not critical. This coefficient is used for estimating the partitioning
          of the dissolved fractions of  the  NAPL (i.e., all of the NAPL chemicals except the chemical
          constituent of interest). For further information on  partitioning see the discussion below for the
          constituent soil/water partition coefficient.

     NAPL surface tension, aao (dyne/cm)

          Enter the NAPL surface tension in dyne/cm.  Table 11 shows typical surface tension values for
          several petroleum products
[Section 4  The MS-Windows Interface]           42

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Table 1 1 Surface tensions of several fuels
(Wu and Hottel, 1991)
Liquid
gasoline
kerosene
gas oil
lubricating fractions
fuel oils
Surface tension
(dyne/cm)
26
25-30
25-30
34
29-32
DISSOLVED CONSTITUENT PROPERTIES

D Dissolved constituent exists

     Check this box if calculations are to be performed for a dissolved constituent.  Normally, for full
     HSSM transport simulation to a receptor point this will be checked.

Initial constituent concentration in the NAPL, c0(lnl) (mg/L)

     Enter the initial concentration of dissolved chemical in the NAPL phase in mg/L.  HSSM idealizes
     the multiphase/multicomponent system as consisting of a NAPL phase that contains some small
     fraction of a dissolved constituent. The  dissolved constituent can partition between the fluids
     and the solid.  The concentration of the chemical in the NAPL is entered here.  For example,
     benzene composes  1.14% by mass of the idealized gasoline mixture  used by Baehr &
     Corapcioglu (1987).  The initial benzene (the chemical constituent) concentration in gasoline (the
     NAPL or "oil")  is given by
                                                                                  (11)
    where Cb is the concentration of benzene in the gasoline, fb is the mass fraction of benzene
    in gasoline, pg is the density of the gasoline.  Therefore
            Cb(gl cm3)  =
1.14%
 100
(0.730/c/n3)  =   0.00830/cm3
(12)
                                        43
                       [Section 4  The MS-Windows Interface]

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          Converting the gasoline concentration to the required units gives
         Cb(mglL)  .  CMcm*)                                  -.  83QQmglL   (13)
                                        V     L     )   \     9    )
     NAPL/water partition coefficient, K,,

          Enter  the linear equilibrium  partitioning coefficient between the  NAPL and the water phase
          concentrations of the chemical constituent. By definition

                                       Co    -   K0cw                                  (14)

          where K0 is the dimensionless partition coefficient between the  NAPL phase (c0) and water
          phase (cw) concentrations of the chemical constituent.  The partitioning between the NAPL phase
          and the water phase depends on the composition of  the NAPL.  Estimation of K0 is discussed
          in Appendix  3.2 "NAPL/Water Partition Coefficient."  A utility  program for performing  the
          necessary calculations, called RAOULT, is described  in Appendix 6.

     Soil/water partition coefficient, K,, (L/kg)

          Enter the linear equilibrium partitioning coefficient in liters per kilogram between the soil and the
          water  phase concentrations (cs and cj of the constituent. By definition


                                       O    '   Kc                                   (15)
          where Kd is the partition coefficient in liters per kilogram between the solid (cs ) and water phase
          concentrations (cw).  Kd is commonly estimated from the fraction organic carbon  of the media,
          foc, and the organic carbon partition coefficient, Koc as


                                       K*    =    foe KOC                                 <16>

          Table 98 in Appendix 3 lists Koc values for several hydrocarbons.

     Constituent solubility, s* (mg/L)

          Enter the chemical constituent water solubility in mg/L. The solubility entered here is the "pure
          component" solubility which is tabulated in several sources (i.e., Mercer et al., 1990;  Sims et al.,
          1991; USEPA, 1990).  Several values are given in Table 98.  The solubility is used by HSSM
          to limit the water phase concentration.  Appropriately chosen K0 values (which imply maximum
          water phase concentrations much less than the pure  phase solubilities) make this parameter
          redundant  for NAPLs composed of mixtures of chemicals.
[Section 4  The MS-Windows Interface]          44

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D Constituent half-life in aquifer (d)

     Enter the half-life of the constituent in the aquifer and check the box. If the box is not checked,
     HSSM-WIN passes a  very large value to the model,  causing there to  be no decay in the
     TSGPLUME model. This value is used only by the TSGPLUME model.
HYDROCARBON (NAPL) RELEASE

     The Hydrocarbon Release box defines, in part, the boundary condition for the simulation.  Four
     options are provided for specifying the way in which the NAPL enters the subsurface.  Not all
     of the release parameters are needed for each release option; the necessary parameters for the
     selected option are highlighted by HSSM-WIN for  entry of the specific values.

Release Options

     O Specified flux

          Specifies a constant flux of NAPL, corresponding to a known rate of application of NAPL
          to the ground surface for a specified time interval.  Excess NAPL is assumed to run off at
          the surface.

     O Specified volume/area

          Specifies a volume per unit area of NAPL applied over a certain depth.  This results in a
          fixed volume applied  instantaneously,  corresponding to a land treatment system  or a
          landfill.

     O Constant head ponding

          Specifies constant head ponding for a specified duration. The ponding depth abruptly goes
          to zero at the end of the release.  This condition  is used to simulate a hydrocarbon tank
          rupture which is contained within a berm, for example.

     O Variable ponding after a period of constant head ponding

          Specifies constant head ponding for a specified duration,  followed by a gradual decrease
          to zero head as the NAPL infiltrates.

Release Parameters

     NAPL flux, q0 (m/d)

          Enter the  constant NAPL flux in meters per day.  NAPL phase fluxes  in excess of the
          maximum effective oil phase conductivity are assumed to run off.

     Beginning time  (d)

          Enter the beginning time of the NAPL release in days.  Usually this is zero.
                                         45          [Section 4  The MS-Windows Interface]

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          Ending time (d)

               Enter the ending time of the NAPL release in days or the ending time of constant head
               ponding.

          Ponding depth, Hs (m)

               Enter the depth of constant head ponding in meters.

          Oil volume/area (m3/m2) or (m)

               Enter the volume of the NAPL phase per unit surface area that is placed in either a land
               treatment facility or a landfill.

          Lower depth of NAPL zone (m)

               Enter the depth of the bottom of the contaminated zone in meters.
4.6.6  Model Simulation Data

     The Model Simulation Parameters dialog box (Figure 22) contains data controlling the simulations,
     such as beginning and ending times, numbers and locations of wells, etc.
     SIMULATION CONTROL PARAMETERS

     Radius of oil lens source, Rs (m)

          Enter the radius of the contaminant source in meters. When no OILENS simulation is desired
          (Run OILENS is not selected on the General Model Parameters dialog box), a per unit area
          simulation can be  performed by entering 0.5642 as the radius of the source.  The resulting
          source area is  1.0 m2.

     Radius multiplication factor

          A value of 1.001 is suggested for the radius multiplication factor (RMF).  The RMF is used to
          multiply the source radius for starting the OILENS model. This is necessary since the OILENS
          equations are singular at the source radius.  Starting the simulation at a small distance from the
          true radius avoids  this singularity.  This procedure does, however,  introduce a mass balance
          error into the solution, so the minimum value of RMF which permits the simulation  to proceed
          should be used.  At no time should the  RMF exceed 1.1.  When the singularity is encountered,
          the OILENS model will display the error message

          OILENS SINGULARITY ENCOUNTERED,  INCREASE RMF.

          The RMF should then be increased, and the simulation retried.
[Section 4 The MS-Windows Interface]

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                                        Simulation Parameters
         SIMULATION CONTROL PARAMETERS

   Radius of NAPL lens source (m). ..
   Radius multiplication factor	
   Max NAPL saturation in NAPL lens .
   Simulation ending time (d)	
   Maximum solution time step (d). ...
   Minimum time between printed time
   steps (d)
   "OILENS Simulation ending criterion
      O User-specified time
      O NAPL lens spreading stops
      O Max contaminant mass flux into aquifer
      (•) Contaminant leached from lens
      Fraction of mass remaining	.1000E-01
            HSSM-T MODEL PARAMETERS
  Percent max. contam't radius (%)
  Minimum output conc'n (mg/L)
  Beginning time (d)	
  Ending time (d)	
  Time increment (d)	
Data file:
CAHSSM\X2BT.DAT
Q E_nable range checking
NAPL LENS PROFILES
Enter time (d) for
each of up to
10 profiles
Number of
profiles
     Cancel
 1
 2
 3
 A
 5
 6
 7
 8
 9
10
25.00
50.00
75.00
                                   100.0
                                   125.0
150.0
                                   200.0
RECEPTOR WELL
LOCATIONS

Enter coordinates
for each of up to
6 wells

Number of wells  ,-
                                                                             X(m)
      Y(m)
25.00
50.00
75.00
100.0
125.0
150.0
.0000
.0000
.0000
.0000
.0000
.0000
Figure 22  Model Simulation Data dialog box

     Maximum NAPL saturation in the NAPL lens, S^^

          Enter the  saturation of the NAPL phase in the lens.  In  HSSM, the lens is idealized as a
          uniformly saturated lens, although in actuality the NAPL saturation varies within the lens.  The
          thickness of the lens  in HSSM represents  the ratio of the volume  of the  lens to its  area.
          Estimation of the NAPL lens saturation is discussed in Appendix 3.3, and a utility called NTHICK
          for performing the necessary calculation is described in Appendix 7.

     Simulation ending time (d)

          Enter the simulation ending time in days.  This must always be specified, even  though  other
          stopping options are available and may override the maximum simulation time.

     Maximum solution time step (d)

          Enter the maximum solution time step in days. This should be set as high as possible, although
          internal error correction routines will often limit the actual size of the step taken.  Values of up
          to 25 days are usually acceptable.  Overly large step sizes may  introduce mass balance errors
          in the model results.
                                              47
         [Section 4 The MS-Windows Interface]

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     Minimum time between printed time steps and mass balance checks (d)

          Enter the minimum time between printed time steps in days. Although the model uses a variable
          time step ordinary differential equation solver, at times during the simulation HSSM takes very
          small steps.  Results from these steps are of little use and dramatically increase the size of the
          output files. This parameter prevents the output of every solution step and should be set to 0.1
          or 0.25 days.  This parameter does not affect the simulation itself, but only the information that
          is output.

          For most chemicals leaching out of  the lens, after the peak mass flux into the aquifer has
          passed, there is  a relatively long period of time where the  mass flux into the aquifer slowly
          declines.  During this time period, the user-set minimum time between printed time steps may
          be overridden in order  to reduce the size of the output and plot files.  An additional criterion is
          added that the mass flux must change by at least 1.0 percent for the results to be output.  This
          feature cannot be overridden by the user.
     OILENS simulation ending criterion

          The OILENS Simulation ending criterion determines how the HSSM-KO simulation terminates.
          Because it is not possible to predict when certain events in the simulation will occur, several of
          the options cause the simulation to end only after the event of interest has occurred. In these
          cases the user-specified ending time is overridden and the simulation  continues until the event
          occurs.

          NOTE:   The  fourth  option, "Contaminant  leached  from lens"  must  be chosen  in
              order to use the HSSM-T model.
          0   User-specified time

              Stop at the simulation ending time specified above.

          ®  NAPL lens spreading stops

              Stop the simulation when the NAPL lens stops spreading.  If no NAPL lens forms before
              the specified ending time, then the simulation stops at the specified ending time. If a lens
              does form, the ending time is overridden and the simulation continues until the NAPL lens
              stops spreading.  When the NAPL phase solubility is near zero, it is possible that, in the
              model,  the lens motion  may never stop, since kinematic theory predicts that an  infinite
              amount of time is required for all of the NAPL to pass a given depth. The NAPL trickles
              into the lens throughout the simulation, and NAPL lens motion stops when the flux into the
              lens drops below the NAPL dissolution flux into the aquifer.  If the NAPL solubility is zero
              and no chemical constituent is simulated,  no NAPL is dissolved and  the  motion  may
              continue indefinitely.  To avoid this problem, a non-zero NAPL solubility (see Hydrocarbon
              Phase Parameters) is required for this situation.

          CD  Maximum contaminant mass flux into aquifer

              Stop the simulation when the maximum chemical constituent flux into the aquifer occurs.
              If no NAPL lens forms before the specified ending time, the simulation stops  at the


[Section 4  The MS-Windows Interface]          43

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          specified ending time.  If a lens forms, the ending time is overridden and the simulation
          continues until the maximum mass flux occurs.

     ® Contaminant leached from tens drops below a given fraction of the total mass in the lens

          Stop the simulation when the contaminant mass in the NAPL lens drops below a specified
          fraction of the maximum contaminant mass that has been contained within the lens during
          the entire simulation. The fraction is specified by the user. If no NAPL  lens forms before
          the user-specified ending time (above), the simulation stops at the specified ending time.

          Fraction of mass remaining

          Enter the mass factor stopping criterion for the above ending criterion ©  "Contaminant
          leached from lens".  Two percent (0.02) or less should be used for this factor.
TSGPLUME MODEL PARAMETERS

The following parameter values are used by the TSGPLUME model only.

Percent maximum contaminant radius (%)
     Enter the percentage of the maximum contaminant radius which is to be used in the TSGPLUME
     simulation, which requires a constant radius for the input mass flux.

     Since the radius of the NAPL lens changes continuously during part of the simulation, it may not
     be possible to preselect an appropriate lens radius for the TSGPLUME module. It is desirable,
     however, to  match the radius of the  lens to the peak mass flux into the aquifer.   Thus
     TSGPLUME simulation can use the radius which occurs at the time of the maximum mass flux.
     With this approach the peak  mass flux is not overly diluted due to a large lens radius.  (Nor is
     it "condensed" due to an  overly small radius). The lens radius which occurs at the time of the
     maximum  mass flux is automatically  selected  if  101  is entered for the percent maximum
     contaminant  radius.   Thus,  the recommended  value of this parameter is  101.  It  may be
     desirable for users to determine the effect of varying the size of the source on the  aquifer
     concentrations.

Minimum output concentration (mg/L)

     Enter the minimum concentration (mg/L) for TSGPLUME  to include  in  the  output.
     Concentrations below this value  will be reported as zero.  A nonzero value of this parameter
     is required for proper execution of the TSGPLUME module.   Typically, a concentration of
     0.001 mg/L is suitable for the minimum concentration.

Beginning time (d)

     Enter the beginning time in days for the TSGPLUME  simulation.  See note  below.

Ending time (d)

     Enter the ending time in days for the TSGPLUME simulation. See note below.
                                        49           [Section 4  The MS-Windows Interface]

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     Time increment (d)

          Enter the time increment in days for TSGPLUME output between the beginning and ending
          times specified above. Typically 50 or 100 days is adequate for the time increment.

          NOTE:  Before  running  the model,  it is  not possible to guess precisely  when the
              contaminant arrives at or passes a given receptor point.  HSSM-T will override the user
              supplied  beginning and ending times which allows the model to produce  smooth
              concentration  histories at the receptor point. Particular effort is expended in HSSM-T to
              calculate  when the contaminant first arrives at the receptor point and when the peak
              concentration  arrives.  The duration of  mass flux into the aquifer is used to determine a
              proposed time increment for HSSM-T output.  If one hundredth of the mass flux input
              duration is greater than the user specified time increment the user is prompted to increase
              the time increment:

              *** TSGPLUME RECOMMENDS  CHANGING  THE TIME INCREMENT
              *** FROM   0.5000  DAYS  TO  98.60 DAYS
              *** ACCEPT  THE CHANGE  ?  (Y OR N)

              HSSM-T  is making  the user  an offer that shouldn't be  refused, at  least for  an
              initial simulation. If the resulting concentration history curve is not smooth enough, the user
              may reduce the time increment for HSSM-T to produce a finer spacing in time.

              If  the  user does not accept  the change,  he/she is  prompted to decide  between
              the original time increment or to enter a new time increment.

     NAPL LENS  PROFILES

     Number of profiles

          Enter the number of KOPT  saturation vs depth profiles (Saturation Profiles graph) and OILENS
          lens thickness vs.  radius profiles (NAPL Lens  Profiles graph).  Both are produced at the
          specified times along with mass balance  approximations.  Up to ten profiles are allowed.

     Time of profiles

          Enter up to ten profile times in days.  The number of entries will be automatically truncated to
          match the value of  Number of profiles above.

     RECEPTOR  LOCATIONS

     These values are used by the TSGPLUME model only.

     Number of wells

          Enter the number of wells (a maximum of six) for which TSGPLUME is to calculate concentration
          vs time  for the Well Concentrations graph.

     Locations of wells

          Enter up to  six well locations, as X and  Y coordinates in meters.  X is the directed along the
          longitudinal axis of  the plume (the direction of groundwater flow) and Y is directed transversely


[Section 4 The MS-Windows Interface]           50

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to the X axis.  The origin of the coordinate system is located at the center of the source (see
Figure 9). The number of entries will be truncated depending on the value of Number of wells
above.
                                    51           [Section 4 The MS-Windows Interface]

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4.7  Running the KOPT, OILENS and TSGPLUME Modules
     This section describes the operation of the HSSM-KO and HSSM-T modules.  These programs are
the heart of the simulation model.  Both of the modules are DOS programs which are executed by selecting
HSSM-WIN menu items. Once an input data file has been created the HSSM-KO module is executed by
selecting the  "Run HSSM-KO" menu item (3a on Table 7) Table 12 shows the first screen that appears
when HSSM-KO is executed.  This screen identifies the model and the authors.  Pressing return displays
the disclaimer screen (Table 13) .   Carefully note  the  disclaimer messages.  Sound  scientific and
engineering judgement is required when applying models and the user is responsible for the application
of the model.


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Table 12 Introductory HSSM-KO Screen


HSSM

HYDROCARBON SPILL SCREENING MODEL

INCLUDING THE KOPT, OILENS AND TSGPLUME MODELS

JAMES W. WEAVER
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
R.S. KERR ENVIRONMENTAL RESEARCH LABORATORY
ADA, OKLAHOMA 74820

INCLUDING OILENS--HYDROCARBON MOVEMENT ON THE
WATER TABLE
RANDALL CHARBENEAU, SUSAN SHULTZ, MIKE JOHNSON
ENVIRONMENTAL AND WATER RESOURCES ENGINEERING
THE UNIVERSITY OF TEXAS AT AUSTIN

VERSION 1.00



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[Section 4 The MS-Windows Interface]          52

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                                Table 13  Disclaimer Screen
            ***************************************************
            *                        WARNING:                       *
            * THIS PROGRAM SIMULATES IDEALIZED BEHAVIOR OF     *
            * OILY-PHASE CONTAMINANTS IN IDEALIZED  POROUS      *
            * MEDIA, AND IS NOT  INTENDED FOR APPLICATION TO    *
            * HETEROGENEOUS SITES.                                *
            * THE MODEL  RESULTS  HAVE NOT BEEN VERIFIED BY      *
            * EITHER LAB OR FIELD STUDIES.                       *
            * READ USER  GUIDE FOR FURTHER  INFORMATION BEFORE  *
            * ATTEMPTING TO USE  THIS PROGRAM.                   *
            * NEITHER THE AUTHORS,  THE UNIVERSITY OF TEXAS,    *
            * NOR THE UNITED STATES GOVERNMENT ACCEPTS ANY     *
            * LIABILITY  RESULTING FROM THE USAGE OF THE CODE  *
            * THE U.S. E.P.A DOES NOT OFFICIALLY ENDORSE THE  *
            * USE OF THIS CODE.                                   *
            ***************************************************
A list of the file names used by HSSM-KO and HSSM-T is displayed in Table 14.
                        Table 14 Output File Names and Run Options
  OUTPUT AND PLOT FILE NAMES:

  HSSM-KO INPUT  DATA FILE    BENZENE.DAT
  HSSM-KO OUTPUT              BENZENE.HSS
  HSSM-KO PLOT 1              BENZENE.PL1
  HSSM-KO PLOT 2              BENZENE.PL2
  HSSM-KO PLOT 3              BENZENE.PL3
  HSSM-T INPUT DATA FILE      BENZENE.PMI
  HSSM-T OUTPUT                BENZENE.TSG
  HSSM-T PLOT                  BENZENE.PMP

  TO RUN HSSM-KO           ENTER 
  TO EXIT                   ENTER 1
The names must follow a strict naming convention for the TSGPLUME module (HSSM-T) and the post-
processors to function properly. Table 15 gives the required file names.  For the user's convenience the
correct file names are generated automatically by either of the interfaces. These should not be modified
by the user.

     As summarized in Table 15, there are eight files associated with each simulation, all with the same
prefix (eight characters or fewer) but different extensions (three characters). *.DAT identifies a data file,
which is edited by HSSM-WIN or PRE-HSSM and read by the HSSM-KO program as an input file.  The
HSSM-KO module generates up to five other files: *.HSS, *.PL1, *.PL2, *.PL3 and *.PMI.  The plot files, *.PL1,
*.PL2, and *.PL3 contain data which HSSM-WIN or HSSM-PLT uses to generate graphs, and the output file,
*.HSS, contains neatly formatted and labelled data for reference. HSSM-KO optionally produces the *.PMI
                                           53          [Section 4 The MS-Windows Interface]

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file, an input file for the HSSM-T program. HSSM-T itself produces two similar files: *.PMP (a plot file), and
*.TSG (a formatted text file).
Table 15 Files Used by the HSSM interfaces
Extension
.DAT
.PMI
.HSS
.TSG
.PL1
.PL2
.PL3
.PMP
Created by
HSSM-WIN or
PRE-HSSM
HSSM-KO
HSSM-KO
HSSM-T
HSSM-KO
HSSM-KO
HSSM-KO
HSSM-T
Used by
HSSM-KO
HSSM-T
the user
the user
HSSM-WIN or
HSSM-PLT
HSSM-WIN or
HSSM-PLT
HSSM-WIN or
HSSM-PLT
HSSM-WIN or
HSSM-PLT
Purpose
data input
data input
text output
text output
data for plotting
data for plotting
data for plotting
data for plotting
As indicated in Table 14  the user may either run HSSM-KO or exit the program.  Upon  beginning a
simulation the model writes messages to  the screen as the computations  proceed.  These allow the
simulation to be tracked by the user. Table 16 contains a typical set of screen messages for a simulation.
[Section 4  The MS-Windows Interface]
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                        Table 16 Typical HSSM-KO Screen Messages
            ***  DATA INPUT
            ***  DATA INITIALIZATION
            ***  SIMULATION BEGINNING
            ***  OIL INFILTRATION
            ***  OIL REDISTRIBUTION
            ***  CHEMICAL  REACHES WATER TABLE
            ***  OIL LENS  FORMS
            ***  PROFILING AT       15.00  DAYS
            ***  PROFILING AT       30.00  DAYS
            ***  PROFILING AT       90.00  DAYS
            ***  PROFILING AT      130.00  DAYS
            ***  PROFILING AT      175.00  DAYS
            ***  SIMULATION END
            ***  POST PROCESSING
            ***  CREATING  OUTPUT  FILE:
            ***  BENZENE.HSS
            ***  PROCESSING PLOT  FILE CONTENTS
            ***  REPACKING FILE 18
            ***  REPACKING FILE 19
            ***  CREATING  KOPT/OILENS PLOT FILE:
            ***  BENZENE.PL1
            ***  CREATING  KOPT/OILENS PLOT FILE:
            ***  BENZENE.PL2
            ***  CREATING  KOPT/OILENS PLOT FILE:
            ***  BENZENE.PL3
            ***  CREATING  TSGPLUME DATA FILE:
            ***  BENZENE.PMI
            ***  HSSM END
     Upon completing the HSSM-KO  simulation,  the DOS window  remains open so that any error
messages stay on the screen.  The window is closed by clicking on  its system menu (upper left hand
corner) and selecting exit.

     The HSSM-T implementation of TSGPLUME is designed to be used with HSSM-KO. If the data set
for HSSM-KO has switches set appropriately, and if the dissolved chemical of interest reaches the water
table (either through the formation of a  NAPL lens or by the leaching from an immobilized NAPL body in
the vadose zone), then an input data set for TSGPLUME is created by running HSSM-KO. The necessary
flags and conditions for TSGPLUME data file generation are summarized in Table 17. These parameters
are described in detail in  the Section 4.6.6.
                                           55          [Section 4  The MS-Windows Interface]

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Table 17 HSSM-KO Data Switches for the Creation of TSGPLUME
(HSSM-T) input Data Files
Condition or switch
H Create output files
H Run KOPT
H Run OILENS
H Dissolved constituent exists
H Write HSSM-T input file
OILENS Simulation ending criterion
© Contaminant leached from lens
"large" Simulation ending time
Dialog box
General
General
General
Hydrocarbon
Phase
General
Simulation
Parameters
Simulation
Parameters
Effect
Output and plot files produced
KOPT module is run
OILENS module is run
Chemical constituent is included in the
simulation.
Attempt to create the TSGPLUME
(HSSM-T. EXE) input data.
End HSSM-KO.EXE simulation when a
small fraction of chemical constituent
remains in the oil lens.
Allow sufficient simulation time for
chemical to reach the water table before
ending simulation.
Once HSSM-KO has run and produced an HSSM-T input data file, HSSM-T can be executed by selecting
the Run HSSM-T menu item (3b on Table 7). When HSSM-T executes, screen messages appear as
shown  in Table 18.   After pressing return, the file names for the simulation  appear as indicated in
Table 19.
[Section 4 The MS-Windows Interface]
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Table 18 Introductory HSSM-T Screen

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TSGPLUME

TRANSIENT SOURCE GAUSSIAN PLUME MODEL


MIKE JOHNSON
RANDALL CHARBENEAU
THE UNIVERSITY OF TEXAS AT AUSTIN

JIM WEAVER
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

VERSION 1.00

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Table 19 HSSM-T Output File Names and Run Options
OUTPUT
AND PLOT FILE NAMES:

HSSM-KO INPUT DATA FILE BENZENE.DAT
HSSM-KO
HSSM-T
HSSM-T
HSSM-T
TO RUN
TO EXIT
OUTPUT BENZENE . HSS
INPUT BENZENE . PMI
OUTPUT BENZENE . TSG
PLOT BENZENE . PMP
TSGPLUME ENTER 
ENTER 1






When HSSM-T executes, a set of messages is written to the screen (Table 20). These messages inform
the user on the progress of the simulation. The example shown has only one receptor location; when more
receptors are used, more messages like these are produced.
                                            57           [Section 4  The MS-Windows Interface]

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Table 20 Typical HSSM-T Screen Messages
*** DATA INPUT
*** DATA INITIALIZATION
*** CALCULATING FLOATING
* * *
*** COMPUTATION BEGINNING
POINT PRECISION
FOR RECEPTOR 1
*** CALCULATING THE TOE TIME OF THE HISTORY
*** SEARCH ALGORITHM COMPLETED IN 6 ITERATIONS
*** COMPUTATION AT 18.18
*** COMPUTATION AT 18.44
*** COMPUTATION AT 33.41
* * * COMPUTATION AT 48.38
*** COMPUTATION AT 63.35
*** COMPUTATION AT 78.32
*** COMPUTATION AT 83.32
*** COMPUTATION AT 88.32
*** COMPUTATION AT 93.32
*** COMPUTATION AT 98.32
*** COMPUTATION AT 103.3
*** COMPUTATION AT 108.3
{other similar messages omi
*** COMPUTATION AT 553.3
*** COMPUTATION AT 603.3
*** COMPUTATION AT 653.3
*** COMPUTATION AT 703.3
*** COMPUTATION AT 753.3
*** COMPUTATION AT 803.3
*** COMPUTATION AT 853.3
* * *
*** OUTPUT FILE:
*** BENZENE1.TSG
*** PLOT FILE:
*** BENZENE1.PMP
*** TSGPLUME END
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
ttedj
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED
DAYS COMPLETED






     Upon completing the HSSM-T simulation, the DOS window remains open so that any error messages
stay on the screen.  The window is closed by clicking on its system menu (upper left hand corner) and
selecting exit.
[Section 4 The MS-Windows Interface]
58

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4.8 Graphical Presentation of HSSM Output

     Six graphs can be automatically generated from a successful HSSM simulation. These graphs provide
a visual summary of the simulation results and include information from each of the three modules of
HSSM.  Table 21 gives information on each of the graphs provided.
Table 21 HSSM Graphics
Title
Saturation Profiles
NAPL Lens Profiles
NAPL Lens Radius
History
Contaminant Mass
Flux History
NAPL Lens
Contaminant Mass
Balance
Receptor
Concentration
Histories
HSSM Module
KOPT
OILENS
OILENS
OILENS
OILENS
TSGPLUME
Description
Vadose Zone Liquid Saturations from the
Surface to the Water Table
Cross-section of the NAPL lens on the water
table
History of the radius of the NAPL lens and the
effective radius of the contaminant
History of the mass flux from the NAPL lens to
the aquifer
History of the mass in the NAPL lens
History of the contaminant concentrations at the
receptor points
Each of the graphics is described in the following sections along with an example figure.
4.8.1  Saturation Profiles

          The saturation profiles (Figure 23) represent the simulated distribution of fluids in the vadose
zone.  The cross-hatched region on the left represents the assumed uniform water saturation.  Plotted
between the water saturation and "1.0" are the NAPL profiles. The profiles are created at the profile times
selected by the user before running the model. The  profile times are listed on the lower right of the figure.
The times correspond to the profiles plotted from right to left (i.e., the outermost profile corresponds to the
earliest time).  The profiles may not turn out to be plotted at advantageous times for display of the results.
The user  may wish to  rerun the model with modified times in order to produce a desired sequence of
profiles.
                                              59
[Section 4  The MS-Windows Interface]

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4.8.2  NAPL Lens Profiles

     The lens profile graph (Figure 24) illustrates the configuration of the lens at the profile times selected
by the user.  The graph  illustrates the configuration of the lens in the vicinity of the water table (vertical
axis). The water table is indicated by the horizontal line.  The horizontal axis shows the lens radius
beginning at the source (radius = 0.0) out to some distance beyond the edge of the lens.  The vertical line
from the top to the  lens indicates contamination in the vadose zone due to the source.  The saturation
profiles  give  the time variation of saturation  within  this region.   The lens shaped body shows the
configuration of the actively spreading NAPL. The hatched areas (which are barely visible in this example)
indicate the region  of the vadose and saturated  zones where there is residual NAPL.  These  regions
develop as the  NAPL lens builds and then  decays.  To step through the sequence of lens profiles, click
on the arrow buttons at the upper left of the graph.
4.8.3  Contaminant Mass Flux History

     The contaminant mass flux history (Figure 25) shows the mass flux of contaminant into the aquifer
as a function of time.  This mass flux is used as the input boundary condition to HSSM-T.  As the NAPL
lens forms, the mass flux to the aquifer increases rapidly, due to the increasing radius of the NAPL lens.
If the source is cut off, as occurs in this example, the mass flux to the aquifer declines because of leaching
of the contaminant into the aquifer. Typically, the mass flux shows a "tailing" effect. In fact, if this graph
does not show decline of the mass flux into the aquifer, then the input mass flux to HSSM-T has been
truncated and the HSSM-T results are  likely in error.


4.8.4  NAPL Radius History

     The NAPL lens radius history shows the radius of the lens as a function of time (Figure 26). The lens
radius increases rapidly as the gasoline enters the lens.  Later the lens tends toward a limiting radius.
4.8.5  NAPL Lens Contaminant Mass Balance

     The NAPL lens contaminant mass balance (Figure 27) shows the mass of contaminant contained
within the NAPL lens as a function of time.  The graph also plots the cumulative mass of contaminant which
has been dissolved into the ground water from the lens.  As the mass contained  within the lens declines,
the cumulative mass dissolved increases proportionately.
[Section 4  The MS-Windows Interface]           QQ

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                Saturation Profiles
 Benzene transport from 1500 gal gasoline spill
 0.00   Depth (m)
 3.00
 6.00
 9.00
 12.0
25.000 d
50 000 d
75.000 d
10000d
125.00 d
150.00 d
200.00 d
    0.00    0.20    0.40   0.60    0.80    1.00
            Total liquid saturation

Figure 23  Typical saturation profiles
                 •|H            un i-ens riuinex
                 '"" Benzene transport from 1500 gal gasoline spill
                  300  Depth (m)
                                                    125.00 days
                                                     9.50
                                                     10.0
                                                     10.5
                                                     11.0
                   0.00         5.00         10.0
                                   Radius (m)
               Figure 24 Typical NAPL tens profile
                                                                                             15.0
            Contaminant Mass Flux
 Benzene transport from 1500 gal gasoline spill
 0 075   Mass flux (kg/d)
 0.060


 0.045


 0.030


 0.015
 0.000
    0.00    1.00    2.00    3.00    4.00
                Time (yr)
                             Radius Histories
               Benzene transport from 1500 gal gasoline spill
               20.00  Radius (m)
               15.00
               10.00
               5.000
                                                   0.000
                                                                             NAPL
                                                                         Contaminant
                   0.00    1.00    2.00    3.00    4.00
                              Time (yr)
Figure 25  Typical contaminant mass flux history  Figure 26 Typical NAPL lens radius history
                                                    61
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         Contaminant Mass in Lens
 Benzene transport from 1500 gal gasoline spill
 Z5.00 ^Moss (kg)
                    Mass in lens
                  Mass dissojved
 20.00
 15.00
 10.00
 5.000
 0.000
    0.00
       Receptor Well Concentrations
Benzene transport from 1500 gal gasoline spill
1 5 00  Concentration (mg/L)
                       X(m)
                       25000
                       50.000
                       75.000
1000 L M        ----   1000°
                       12500
                                             5.000
                                             0.000
                                                                    150.00
3.00
                               1.00
                                                000
          1.50    3.00
             Time (yr)
                                                                    1.50
                                                  Y(m)
                                                  00000
                                                  00000
                                                  00000
                                                  °0000
                                                  00000
                                                  0.0000
                                                                          6.00
           1.00    2.00
              Time (yr)
Figure 27  Typical NAPL lens contaminant mass  Figure 28  Typical receptor concentration histories
balance
4.8.6  Receptor Concentration Histories

     The receptor concentration histories (Figure 28) show the predicted concentrations at the user-
selected receptor points.  Concentrations above the specified threshold are plotted as a function of time
for each receptor location.  Care should be taken to identify the threshold value input to the model in order
to assure that the value has not been set too high and as  a result truncated concentration histories are
plotted in this graph.


4.9  A Note on the  Efficiency of Using the Windows Interface

     The computational modules of HSSM (HSSM-KO and HSSM-T) execute more rapidly under DOS than
they do under Windows. Within Windows, the HSSM-KO and HSSM-T models run faster as a full screen
process than in  a DOS window.  In some cases, the most time-efficient way to use the Windows interface
is to use  HSSM-WIN as a preprocessor to create several input data files, then exit HSSM-WIN and run
HSSM-KO and HSSM-T under DOS (Appendix 1.9).  The commands for running HSSM-KO and HSSM-T
from DOS are

HSSM-KO  name.dat
HSSM-T name.pmi

where  name.dat  is the input data set created by HSSM-WIN and  name.pmi is the HSSM-T input data file
created by running HSSM-KO. The results can be viewed  by reentering HSSM-WIN and plotting graphs
of the results.
[Section 4  The MS-Windows Interface]
                      62

-------
4.10 Menu Command Reference

     This section lists each HSSM-WIN command an briefly describes its action.  The italicized number
and letter refer to the columns and rows of Table 7, respectively.
Fite (1)

     The File menu lists commands for manipulating files, and includes the option to Exit HSSM-WIN.

     New (1.a)
         New clears the memory of parameters and file names, restoring HSSM-WIN to its startup state.


     Open... (l.b)
         The Open dialog box (Figure 13) is used to open a data file.  This file contains  the input data
         for the model programs.  Once opened by HSSM-WIN, the data are available for editing or
         saving under a new name.

     Save (1.c)
         Save  will save the  current parameter settings in the current file, which is displayed in HSSM-
         WIN's caption bar.

     Save As...  (1.d)
         The Save As dialog box (Figure 14) will prompt for an alternate file name under  which to save
         the current settings. When entering the name, it is sufficient to enter only the prefix (the first
         eight  or fewer characters).  HSSM-WIN will tack on the appropriate extension  if you have not.

     Check File Times (1.e)

         This selection checks the file creation  or modification times to prevent  HSSM-T from being
         executed with an outdated input file. Normally, if an HSSM-KO input data file has been modified,
         HSSM-T should not be run before HSSM-KO has been run or rerun.

         When  this selection  is  activated, HSSM-T is prevented from  being
         executed if the HSSM-KO input data file has a later date/time than the HSSM-T input data file.
         Plotting files are also checked to see if  they predate the data input files, in which  case the user
         is prompted to rerun the model.  Sometimes, as when files are moved from  one directory to
         another, the user may wish to override  this safety feature.

     Exit HSSM-WIN  (1.f)
         This selection is used to terminate HSSM-WIN and clear the screen of all graphs.


Edit (2)

     General Data (2.a) is used to set various model switches and to select titles for the  graphs.

     Hydrologic  Data  (2.b) is used to input hydrologic and hydraulic variables.




                                             63          [Section 4 The MS-Windows Interface]

-------
     Hydrocarbon Phase Data  (2.c) is used to choose parameters related to the NAPL phase and the
     chemical constituent.

     Model Simulation Data (2.d) is used to input options which control the simulations by HSSM-KO and
     HSSM-T.

     Information about the  meaning and appropriate values for each item in the data entry dialog boxes
     is given in Sections 4.6.3  through 4.6.6.
Model (3)
     Run HSSM-KO (3.a)
          Causes  HSSM-KO to execute  under  using  the current  HSSM-KO input  data
          file.

     Run HSSM-T (3.b)
          Causes HSSM-T to execute using the current HSSM-T input data file.

     Run REBUILD (3.c)
          Causes REBUILD  to execute and attempt to recover temporary files from an interrupted or
          unsuccessful run.
Graph (4)

     The Display Graphs (4.a) dialog box (Figure 15) will prompt the user for which graphs to generate and
     will draw them on the screen.

     In the event that no oil lens has formed or the TSGPLUME model was not run, some graphs will not
     be available for display,  and their checkboxes will be empty. Attempting to select these boxes will
     produce a message about their  unavailability.   For example,  in Figure 15 the Receptor Well
     Concentrations are not available.

     Copy Graph (4.b) copies the contents of the graph window, in its current size and configuration, to
     the Windows Clipboard, a data storage facility available to all Windows applications. Once copied to
     the Clipboard, the graph can be transferred to other applications such as PAINTBRUSH or WRITE
     using the "Paste" command within those applications.  Nothing can be pasted into HSSM-WIN, but
     the graphs can be exported as bitmaps this way.

     Print Graph (4.d) prints a copy of the graph on the printer that Windows currently recognizes. (Choice
     of printers is available through the Windows Control Panel).  HSSM-WIN attempts to make an actual
     size copy of the graph window on the printed page, so what appears in the graph window is what will
     appear on paper. Small  graphs print  fairly quickly (several seconds), but larger ones will take longer
     since there are more points to transfer.  A full-screen graph will be scaled down to fit on the page,
     and may take several minutes, depending on the sophistication of the printer.

     HSSM-WIN's print function does not support plotters or daisy-wheel printers, since they cannot print
     bitmaps.

     Close  Graph  (4.e) closes  the currently  selected  graph.   Graphs may also  be closed
     by double clicking on their system menus.

[Section 4 The MS-Windows  Interface]          64

-------
     Fonts  (4.f)  allows the selection of alternative fonts for lettering the HSSM  graphics.
     Various fonts may be chosen for the graph title, axis labels, and legends. The default option returns
     all graph text to the default font.
Window (5)
     Cascade (5.a)
          Arranges the graph windows in a cascaded formation.

     Tlte (S.b)
          Arranges the graph windows in a tiled formation.

     Arrange Icons (5.c)
          Neatly rearranges the graph icons.  The spacing of these icons is determined by the setting in
          the Desktop applet in control panel.

     Close All (5.d)
          Closes all of the graph windows and removes them from memory.
Help (6)

     Read Help File (6.a)
         The Help file, HSSMHELP.WRI, can be read using WRITE, the standard file editor which comes
         bundled with Windows. Figure 29 shows a sample of this Help file.

     About HSSM and About HSSM-WIN (6.b and 6.c)

         The "About" dialog boxes provide information pertaining to the origins of the programs.

The System Menu (7)

     The system menu, common to all windows programs, is accessed by clicking on the spacebar icon
     in the upper left corner of the window or by typing ALT + SPACEBAR from the keyboard.  In addition to
     choosing various modes of display of the window, the program may also be terminated.
                                             65           [Section 4 The MS-Windows Interface]

-------
                            Write-HSSMHELP.WRI
 file  £dlt  Rnd   Character  JEaragraph  Document  Melp
                         USING WRITE TO VIEW ON-LINE DOCUMENTS

   * If you enlarge Write to its maximum size, the following document will be easier to read. To
       Maximize button in the upper-right corner of the Write window. Or open the Control
       space bar icon) in the upper-left corner of the Write window and choose Maximize.

   * To move through the document, press  PAGE  UP and PAGE DOWN  or click the  arrows
       bottom of the scroll bar along the right of the Write window.

   * To print the document, choose Print from the Write File menu.

   * To search for a particular text string, use the Search command.

   * This file assumes that your Windows system has the TrueType typefaces Anal and Symbol ir

   * This file may be easily edited by  yourself.  With Write, you may reformat the text and
       document before printing, if desired.  The equations will not be visible to the versions
       Windows 3.0 or earlier. For Help using Write, press F1.
                                  Help for HSSM-WIN

                    ShowFlow Windows Interface version 3.10 for the
Figure 29  HSSM-WIN "Help" information in HSSMHELP.TXT
 [Section 4 The MS-Windows Interface]
66

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Section 5  Example Problems


     In this section, two example problems are presented along with HSSM input data sets and graphic
of the results. The complete set of input and output files is distributed on the HSSM-2 diskette.  The intent
of these examples is to provide guidance in application of the model to similar problems.  Each begins with
a brief description of the problem including some values of model  parameters which are assumed to be
well-known.  The examples then  proceed with a discussion of the specific rationale used for the selection
of each parameter of the model.  The parameters are listed in the order that they appear in the Windows
interface.
5.1  Problem 1: Gasoline Arrival Time at the Water Table

     An emergency response and monitoring plan is being prepared for an above-ground storage tank
facility.   An estimate is needed of how long it would take gasoline to reach the water table and what
monitoring frequency would be required to detect a leak before gasoline reaches the water table.  The soil
has been classified as  a sandy clay loam soil.  In this example, the water table lies at a depth of 5.0
meters. All of the parameters for the model run are saved in the file X1STF.DAT.  HSSM-WIN can be used
to page through the input parameters as the example is studied. The  file may  be  loaded and viewed
according to the instructions in section 4.5.2 "Creating and  Editing Input Data Sets."

     This problem needs the use of the KOPT module with no dissolved  contaminant.  A "per unit area"
simulation should be performed because only the transport time through the vadose zone is required. Of
all the  input data required for the model, only the  following parameters are required for the "KOPT only"
simulation.   HSSM-WIN places necessary zeros in  the  data  file for  the  unused parameters.   The
presentation of the input data follows the order of the four HSSM-WIN input data dialog boxes.

     The first of the boxes, "General Model Parameters," contains the run title, printing switches, module
switches and the file names.  For this example, the run title is

Gasoline Release from an Aboveground Storage Tank Fac.
Gasoline Arrival Time at the Water Table
KOPT Simulation Only
                                                      •
The "create output files" switch is checked in order to write the output files. For the first attempt at running
a new  data set, it is recommended to echo print the input  data only and check the parameter values by
reading the *.HSS output file.  Only  the Run KOPT module switch is checked as only  KOPT is needed to
estimate the gasoline arrival time at the water table.  The output file names are automatically generated
by the  interface and  shown in the FILE  names area of the dialog box.  The file name used for this
simulation is X1STF.DAT.  The completed dialog box appears as shown in  Figure 30.
                                             67                  [Section 5 Example Problems]

-------
Run Jjfles:
| Gasoline Arrival Time at the Water Table
















•

KOPT Simulation Only

"Erinting switches "
E3 Create output files
O Echo print data only
(§) Run models

File nnmos

Module switches
E3 Run KOPT
DRunOILENS
D Write HSSM-T input file
| OK |

I Cancel










NOTE: These filenames mil be used if the data file
is saved under a new name with the "SoveAs" option.
C:\HSSM\X1STF.DAT
C:\HSSM\X1STF.HSS
C:\HSSM\X1STF.PL1
C:\HSSM\X1STF.PL2
C:\HSSM\X1STF.PL3
C:\HSSM\X1STF.PMI
C:\HSSM\X1STF.TSG
C:\HSSM\X1 STF.PMP

HSSM-KO input file
HSSM-KO output file
HSSM-KO plot file 1
HSSM-KO plot file 2
HSSM-KO plot file 3
HSSM-T input file
HSSM-T output file
HSSM-T plot file

























Figure 30  Problem 1 completed General Parameters dialog box


     The second dialog box, "Hydrologic Parameters" contains the hydrologic and soil properties.

Hydrologic Properties

     The parameters shown in Table 22 are used for the Hydrologic Properties.  Standard fluid properties
are used for the water phase. During infiltration, some of the air in the pore space is not displaced by
either the  water or the NAPL.  It is assumed that during infiltration the maximum hydraulic conductivity to
water is one-half of the saturated  hydraulic conductivity.  From this assumption,  HSSM automatically
determines the amount of air trapped in the pore space.
[Section 5  Example Problems]
68

-------
Table 22 Problem 1 Hydrologic Properties
Parameter
Water Phase Viscosity, uw
Water Phase Density, pw
Water Phase Surface Tension,
°aw
Maximum Relative
Permeability During Infiltration,
k
^rwlmax)
Recharge Input Type
Water Saturation, Sw(max)
Rationale
Standard value
Standard value
Assumed
Assumed
Specify Saturation
Specified water saturation
Value
1.0 cp
1 .0 g/cm3
65.0 dyne/cm
0.5

0.35
Capillary Pressure Curve Model and Porous Medium Properties

     The porous medium properties are estimated from Brakensiek et al.'s soil parameter  tabulation for
the Brooks and Corey model. The  values shown in Table 23 are taken from the tabulation reproduced
in Appendix 3.1.
Table 23 Problem 1 Porous Medium Properties
Parameter
Brooks and Corey's Pore Size
Distribution Index, X
Air Entry Head, hce
Residual Water Content, 9wr
Porosity, r)
Value
0.368
46.3 cm
0.075
0.406
Thfe residual water saturation that is required by HSSM is calculated by dividing the residual water content
by the porosity to get 0.18 (0.075/0.406).
                                              69
[Section 5 Example Problems]

-------
      The hydraulic conductivity in cm/s of the system is then estimated from (Brakensiek et al., 1981)
=   270^
                                                           =   8.68x1Q-4c/77/s
                                                                     (17)
 where the air entry head is in centimeters. The value is then converted to the units of meters per day by
 multiplying by 864 to give a Ks of 0.75 m/d.    From the basic soil  property  information, the following
 parameters are determined (Table 24).  The completed dialog box is shown in Figure 31.   Note that in all
 of the dialog boxes for Problem 1  range checking is disabled. This is shown by the open check box (a)
 below the file name.  Range checking must be disabled for KOPT only simulations, because many of the
 input parameters default to normally-disallowed zeros.
                                        Hydrologic Parameters
               HYDROLOGIC PROPERTIES
     Water dynamic viscosity (cp) .
     Water density (g/cm*)	
     Water surf, tension (dyne/cm).
     Maximum krw during infiltration
      •Recharge	
      O Average recharge rate (m/d)
      <•) Saturation
      'Capillary pressure curve model
      <§> Brooks and Corey
      O van Genuchten
       Brooks and Corey's lambda
       Air entry head (m)	
       Residual water saturation ...
       van Genuchten's alpha (1 /m)
       van Genuchten's n	
                       Data file:
                       C:\HSSM\X1 STF.DAT

                       D Enable range checking
Cancel
                               POROUS MEDIUM PROPERTIES
                       Sat'd vert hydraulic cond. (m/d)..
                       Ratio of horz/vert hyd. cond	
                       Porosity	
                       Bulk density (g/cm*)	
                       Aquifer saturated thickness (m)...
                       Depth to water table (m)	
                       Capillary thickness parameter (m)
                       Groundwater gradient (m/m)	
                       Longitudinal dispersh/Hy (m)	
                       Transverse dispersrvity (m)	
                       Vertical disparsivity (m)	
 Figure 31  Problem 1 completed Hydrologic Properties dialog box
[Section 5 Example Problems]
                      70

-------
Table 24 Problem 1 Hydraulic Conductivity and Capillary Pressure Curve Parameters
Parameter
Ratio of Horizontal to
Vertical Conductivity
Porosity, T|
Depth to Water Table
Rationale
Arbitrary value as this parameter is not used in
KOPT
From Brakensiek et al. 1981 Tabulation
Arbitrary value as only KOPT is used
Value
5.0
0.406
10.0m
Hydrocarbon Phase Parameters

     Table 25 shows the NAPL fluid property values that are entered in Figure 32.  These are intended
to represent gasoline.
Table 25 Problem 1 Hydrocarbon (NAPL) Phase Properties
Parameter
NAPL Phase Density, p0
NAPL Phase Viscosity, u0
Residual NAPL Saturation
(vadose zone), Sorv
NAPL Surface Tension, aao
Rationale
Typical value for gasoline
Typical value for gasoline
Estimated
Estimated
Value
0.74 g/cm3
0.45 cp
0.10
35.0
dyne/cm
Hydrocarbon Release

     The hydrocarbon (NAPL) release scenario is chosen by selecting the radio button for constant head
ponding (Figure 32). The beginning time, ending time and ponding depth are entered to define the release.
The release is assumed to begin at 0.0 days and end at 1.0 day.  During this interval the ponding depth
is assumed to remain constant at 0.05 m (5 cm).
                                              71
[Section 5 Example Problems]

-------
         HYDROCARBON PHASE PROPERTIES

   NAPL density (g/cm«)	
   NAPL dynamic viscosity (cp).
   Hydrocarbon solubility (mg/L).
   Aquifer residual NAPL saturation...
   Vadose zone residual NAPL sat'n..
   Soil/water partition coeff. (L/kg)...
   NAPL surface tension (dyne/cm)...
       DISSOLVED CONSTITUENT PROPERTIES
   CD Dissolved constituent exists
   Initial constit. cone, in NAPL (mg/L)..
   NAPL/water partition coefficient	
   Soil/water partition coeff. (L/kg)....
   Constituent solubility (mg/L)	
   D Constit. It-life in aquifer (d)	
                                      Cancel
Data file:
C:\HSSM\X1STF.DAT
Q Enable range checking


[-HYDROCARBON RELEASE	
  O Specified flux
  O Specified volume/area
  <§) Constant head ponding
  O Variable ponding after const head period

  NAPL flux (m/d)
  Beginning time (d)
  Ending time (d)
  Ponding depth (m)
  NAPL volume/area (m).
  Lower depth of NAPL zone (m)..
Figure 32 Problem 1  completed Hydrocarbon Phase Properties dialog box
Simulation Parameters

     The remaining parameters are shown in the Simulation Parameters dialog box (Figure 33).   These
define the source area, time stepping, profile times and ending criterion as indicated in Table 26.
Table 26 Problem 1 Simulation Control Parameters
Parameter
Radius of the NAPL Source, Rs
Simulation Ending Time
Maximum Solution Time Step
Minimum Time Between
Printed Time Steps
Rationale
A "per unit area" simulation is desired, the value
0.5642 results in a 1.0 m2 source area
Simulate the release for 25 days, since gasoline
is a low viscosity fluid and can reach the water
table relatively rapidly in a permeable media.
Use a relatively small value, because only 25
days are simulated
Use a value smaller that the minimum solution
time step.
Value
0.5642 m
25 days
0.1 day
0.05 day
     Five profiles times are  used for the simulation.  The times should be small, since the  gasoline is
expected to reach the water table relatively rapidly. Use times of 0.25, 0.5, 1.0, 2.0 and 5.0 days (6, 12,
[Section 5 Example Problems]
72

-------
24, 48 and 60 hours).  HSSM-WIN requires at least one groundwater receptor be indicated.
receptor is arbitrarily located at (0.0,0.0).
                    Here the
— Simulation Parameters
F
h
E
E
T
SIMULATION CONTROL PARA
Radius of NAPL lens source (m) 	
Max NAPL saturation in NAPL lens . .
Simulation ending time (d) 	
Maximum solution time step (d) . . . .
Minimum time between printed time
steps (d)
METERS
.5642
.0000
.0000
25 00
.1000

.5000E-01 1

' OILENS Simulation ending criterion"
<•) User-specified time
O NAPL lens spreading stops
O Max contaminant mass flux into aquifer
O Contaminant leached from lens
Fraction of mass remaining 	
nnnn

HSSM-T MODEL PARAMEn
ercent max. contam't radius (%) 	
linimum output conc'n (mg/L) 	
eginning time (d) 	
tiding time (d) 	
ime increment (d) 	
rERS
.0000
.0000
.0000
.0000
.0000

Data file:
C:\HSSM\X1STF.DAT
D Enable range checking
NAPL LENS PROFILES
Enter time (d) for
each of up to
10 profiles
Number of . 	 ,
profiles [5 	 |
RECEPTOR WELL
LOCATIONS
1
Enter coordinates 2
for each of up to 3
6 wells
Number of wells , 	 ,
[i | B
1
2
3
A
5
6
7
B
9
10
X(m)
0.0





i"™"!^""^"!
| ,OK;
Cancel

.2500
.5000
1.000
2000
5.000





Y(m)
0.0







 Figure 33  Problem 1  completed Simulation Parameters dialog box
Problem 1  Model Results

     The model is executed by entering the command

HSSM-KO  X1STF.DAT

     The saturation profiles from the simulation are shown in Figure 34.  These profiles were drawn with
the HSSM-PLT program.  The depth of the sharp front increases with time and the first three profiles show
uniform NAPL saturations.  The last two profiles show  varying NAPL  saturations,  because they occur at
48 and 60 hours which both are past the end of the release (24 hours).

     With complete confidence in  the accuracy of the input data, it could be assumed that the gasoline
never reaches the water table.   Most of the model parameters used in this example have been estimated
from published tabulations. Rather than accepting the results of one simulation  as being authoritative,
several simulations should be run in order to get some feel for the effects of parameter variability.  If the
hydraulic conductivity was in fact 10 times greater than the average value of 0.75 m/d, the gasoline would
flow deeper into the subsurface. Because of the constant head ponding condition assumed for this case,
the gasoline would also flow faster. The constant head ponding condition does not specify the volume of
gasoline which enters the soil;  it only indicates that enough gasoline is  supplied to maintain the 0.05 m
ponding depth for one day. Figure 35  shows the NAPL front position when the hydraulic conductivity is
7.5 m/d.   By 25 days, the gasoline would reach 24 meters deep, if not for the water table  5.0  meters
deep. From the X2STF.HSS file, the depth of 5 meters was reached within 9.8 hours.
                                              73
[Section 5 Example Problems]

-------
    This example has focussed on the role of the hydraulic conductivity in determining the depth of the
gasoline.  The effect of variation in other parameters can likewise be demonstrated.  Some of the other
uncertain  parameters  are  the  assumed release  condition,  moisture content,  and capillary pressure
parameters.

                                  Saturation Profiles
          Gasoline Release  from an Above Ground Storage Fac.
          0 00    Depth (m)
          1.00
          2.00
          3.00
                                                               0.2500 d
                                                               0.5000 d
                                                               LOQOOd
                                                               2.0000 d
                                                               5.0000 d
             0.00       0.20        0.40       0.60
                              Total liquid saturation
              0.80
1.00
 Figure 34 The storage tank example saturation profiles
[Section 5 Example Problems]
74

-------
                                         Saturation Profiles
                 Gasoline Release from an Above Ground Storage Fac.
                 0.000
                 5.000
                 10.00
                 15.00
                 20.00
                                                                     0.2500 d
                                                                     0.5000 d
                                                                     LOOOOd
                                                                     2.0000 d
                                                                     5.0000 d
                    0.00       0.20       0.40       0.60
                                      Total liquid saturation
0.80
1.00
Figure 35  Storage tank facility example with increased conductivity
                                              75
   [Section 5 Example Problems]

-------
5.2   Problem   2:  Transport of Gasoline Constituents in  Ground Water to  Receptor
Locations

     During a one-day period, 1500 gallons of gasoline leak from a tank surrounded by a circular berm of
2.0 meter radius.    Benzene is believed to compose 1.15% by  mass of the  gasoline.   The benzene
concentration in the ground water at locations 25, 50,  75, 100, 125 and 150 meters away are needed to
assess the impact of the spill. The soil is believed to be predominantly sand in the vicinity of the spill. The
aquifer is 10 meters below the ground surface, and its saturated thickness is 15 meters.

     Complete information for the site is not available so many of  the HSSM parameters must  be
estimated.  In the absence of better information, parameter values will be estimated from tabulations from
the literature.  The data set for this example will be organized according to the 4 dialog boxes for entering
data in HSSM-WIN.  The parameters for this example are found in the file X2BT.DAT, which is found on the
HSSM-WIN distribution diskette. The file may be loaded and viewed according to the instructions in section
4.5.2 "Creating and Editing Input Data Sets."

     The first of the boxes, "General Model Parameters," contains the run title,  printing switches,  module
switches and the file names.  For this example, the run title is

Benzene transport from 1500 gal gasoline release
Benzene  1.15% by mass of gasoline
sandy soil from Carsel and Parrish Data set

The "create output files" switch is checked in order to write the output files. For the first attempt at running
a new data set, it  is recommended to echo print the input data only and check the parameter values by
reading the *.HSS  output file.  Each of the Module switches is checked,  because all three of the HSSM
modules are needed for estimating the receptor concentrations.   At this point the names are of no concern
as they are added automatically when the file is saved.  The file name used for this simulation is X2BT.DAT.
The completed dialog box appears as shown in Figure 36.
[Section 5 Example Problems]

-------
— General Model Parameters
Run Titles:


















Benzene transport from 1 500 gal gasoline spill
1.15% benzene in gasoline
sandy soil, properties from Corse! and ParrisK

Pointing switches
Kl Create output files
O Echo print data only
(•) Run models

File names

Module switches
13 Run KOPT
Kl Run OILENS
13 Write HSSM-T input file

| OK


I Cancel I









NOTE: These filenames will be used if the data file
is saved under a new name with the "SaveAs" option.
C:\HSSM\X2BT.DAT
C:\HSSM\X2BT.HSS
C:\HSSM\X2BT.PL1
C:\HSSM\X2BT.PL2
C:\HSSM\X2BT.PL3
C:\HSSM\X2BT.PMI
C:\HSSM\X2BT.TSG
C:\HSSM\XZBT.PMP

HSSM-KO input file
HSSM-KO output file
HSSM-KO plot file 1
HSSM-KO plot file 2
HSSM-KO plot file 3
HSSM-T input file
HSSM-T output file
HSSM-T plot file

























 Figure 36  Problem 2 completed General Parameters dialog box
     The second dialog box, "Hydrologic Parameters" contains the hydrologic and soil properties.

Hydrologic Properties

     Standard properties of water are used for the simulation: density of 1.0 g/cm3, viscosity of 1.0 cp,
and surface tension of 65 dyne/cm.  During infiltration, some of the air in the pore space is not displaced
by either the water or the NAPL.  It is assumed that during infiltration the maximum hydraulic conductivity
to water is one-half of the saturated hydraulic conductivity.   From this assumption, HSSM automatically
determines the amount of air trapped in the pore space.

Recharge

     The average annual recharge rate at the release site is estimated to be 50 cm/year. When converted
into the required HSSM units of meters per day, the recharge rate is 0.0014 m/d.

Capillary Pressure Curve Model and the Porous Medium Properties

     The tabulation of soil parameters developed by Carsel and Parrish (1988) will be used for the soil
properties because of the relatively large number of samples used in developing the statistics  for the sand
classification. The parameters in Table 27 are taken from the tabulation (which is reproduced in Appendix
3.1).
                                              77
[Section 5 Example Problems]

-------
Table 27 Problem 2 Hydraulic Properties
Parameter
Hydraulic conductivity, Ks
Residual water content, 0W
Saturated water content, 0m
van Genuchten capillary parameter "a"
van Genuchten capillary parameter "n"
Average value from
Carsel and Parrish
(1988)
7.1 m/d
0.045
0.43
4.5 nV1
2.68
These parameters form the basis for several of the other required input parameters on the  "Hydrologic
Parameters" dialog box.  The parameter listed in Table 28 are derived from the soils data.
Table 28 Problem 2 Parameters Derived from the Hydraulic Properties
Parameter
Residual water
saturation, Swr
Ratio of horizontal to
vertical conductivity
Porosity, r)
Bulk density, pb
Rationale
HSSM requires residual saturation to be
entered, rather than residual moisture
content.
Swr = 6wr /Om
The sandy soil is assumed to be only slightly
anisotropic.
The porosity is taken as being equal to the
saturated water content.
In terms of porosity and solid density, the
bulk density is pb = ps(1 - r)).
Value
0.10
(0.045/0.43)
2.5
0.43
1.51 g/cm3
2.65 g/cm3 (1 - 0.43)
     The aquifer saturated thickness is 15.0 meters, and the depth to the water table is 10.0 meters.  For
this simulation, no smear zone is included; so the NAPL is allowed to spread out freely along the water
table. Thus the capillary thickness parameter is set to a minimum value of 0.01 m.

     The ground water gradient is estimated to be 1 foot per hundred or 0.01. The longitudinal dispersivity
is taken as 10 meters.  This value follows from the rule of thumb that says that the longitudinal dispersivity
could be one tenth the distance  to the receptor point (100 m).  The horizontal transverse dispersivity is
assumed to be 1 meter and the vertical transverse dispersivity is assumed  to be 0.1 m.
[Section 5  Example Problems]
78

-------
At this point the "Hydrologic Parameters" dialog box of HSSM-WIN can be completely filled in (Figure 37).
                                      Hydrologic Parameter?
             HYDROLOGIC PROPERTIES
    Water dynamic viscosity (cp).
    Water density (g/cm*)	
    Water surf, tension (dyne/cm).
    Maximum krw during infiltration .
Data file:
C:\HSSM\XZBT.DAT
CH Enable range checking
I  [OKI    I

| Cancel   |
    "Capillary pressure curve model
     O Brooks and Corey
     (•) van Genuchten

     Brooks and Corey's lambda
     Air entry head (m)	
     Residual water saturation
     van Genuchten's alpha (1 /m)
     van Genuchten's n	
                                                       POROUS MEDIUM PROPERTIES
Sat'd vert, hydraulic cond. (m/d) . .
Ratio of horz/vert hyd. cond	
Porosity	
Bulk density (g/cm*)	
Aquifer saturated thickness (m)...
Depth to water table (m)	
Capillary thickness parameter (m)
Groundwater gradient (m/m)	
Longitudinal dispersivity (m)	
Transverse dispersivity (m)	
Vertical dispersivity (m)	
 Figure 37 Problem 2 completed Hydrologic Properties dialog box
Hydrocarbon Phase Properties

     The first group of parameters is used to describe the properties of the NAPL itself, which is assumed
to be an inert oily phase. The density and viscosity of gasoline are typically near 0.74 g/cm3 and 0.45 cp,
respectively.   The solubility of the NAPL is  arbitrarily taken as 10 mg/l.  A small amount of the NAPL
phase will dissolve during the simulation, but this amount has little effect on the dissolved constituent of
interest.   Residual NAPL saturations are  specified for the aquifer (0.15) and the vadose zone (0.05).
These values are estimates, but reflect the fact that the residual in the aquifer is likely to  be higher than
that in the vadose zone (Wilson et al.,  1990).  The soil/water partition coefficient for the NAPL phase is
taken to be 0.83.  The NAPL or "oil" surface tension is assumed to be about half of the water/air surface
tension, aao or 35 dyne/cm.
Dissolved Constituent Properties

     Since the object of the simulation is to estimate down gradient concentrations of a chemical of interest,
the dissolved constituent exists box  is checked.  The initial constituent concentration (of benzene) is
calculated from its mass percentage in the gasoline.  The dissolved constituent check box is selected to
tell HSSM that a dissolved constituent of the NAPL should be simulated.

     Since the  benzene is present in the gasoline at a mass fraction of  1.14% and the density of  the
gasoline is 0.72 g/cm3, the initial concentration of benzene in the gasoline is
                                                 79
                       [Section 5  Example Problems]

-------
           Q2Q8mglL    =
              1.14%
                100
(0.72 glcm3) (1000 cm3IL) (1000 mglg)      (18)
The Oil/Water (NAPL/Water)  partition coefficient, K0, will be assumed to be equal to 311 as determined
from the RAOULT utility (Appendices 3.2 and 6). The benzene partition coefficient between the soil and
water,  Kd, is 0.083 L/kg.  The value is  determined by multiplying the assumed fraction organic carbon
(0.001) by the value of Koc (83).  The value of Koc is taken from Table 98  in Appendix 3.2.  The  water
solubility of benzene is about 1750 mg/l.  This value is an absolute limiting  value for the simulation. The
actual  solubility of benzene in the gasoline is determined by the partition coefficient.   No degradation of
the benzene will be assumed for the HSSM-T model,  so the half-life check box is unchecked.

Hydrocarbon Release

     The release  in this example is given as a volume released  during  a certain  time interval.   The
appropriate release definition for this situation is the specified flux release. The required input parameters
are the beginning time in days and the ending time in days, and the NAPL flux  in meters per day. The
beginning time is 0.0 days and the ending time is 1.0 days.  The  NAPL flux, q0,  is calculated by dividing
the release volume by the source area and the duration.
q0   =  0.4522 mjd  =
                                                          .5gal)
                                                     ft
                                                   (19)
                                                  (it (2.0 m)2)  LOctey
The completed dialog box is shown in Figure 38.
                                  Hydrocarbon Phase Parameters
         HYDROCARBON PHASE PROPERTIES

   NAPL density (g/cm*)..
   NAPL dynamic viscosity (cp)
   Hydrocarbon solubility (mg/L)
   Aquifer residual NAPL saturation..
   Vadose zone residual NAPL sat'n.
   Soil/water partition coeff. (L/kg)
   NAPL surface tension (dyne/cm)

        DISSOLVED CONSTITUENT PROPERTIES

   ^Pjssolved constituent exists
   Initial constit. cone, in NAPL (mg/L)..
   NAPL/water partition coefficient	
   Soil/water partition coeff. (L/kg)	
   Constituent solubility (mg/L)	
   O £onstit. 'A-life in aquifer (d)	


J 	
ition 	
sat'n. . .
kg) ....
cm). . . .
.7200
.4500
10.00
.1500
.5000E-01
.8300E-01
35.00
                              Data file:
                              C:\HSSM\X2BT.DAT
                              CH Enable range checking
                                           OK
                                          Cancel
                              -HYDROCARBON RELEASE	
                                (•) Specified flux
                                O Specified volume/area
                                O Constant head ponding
                                O Variable ponding after const head period

                                NAPL flux (m/d) ..
                                Beginning time (d)
                                Ending time (d)
                                Ponding depth (m)
                                NAPL volume/area (m)
                                Lower depth of NAPL zone (m)
 Figure 38  Problem 2 completed Hydrocarbon Phase Properties dialog box
[Section 5  Example Problems]
                             80

-------
Simulation Control Parameters

     A number of parameters interact to control the various aspects of the simulation.   These are listed
in Table 29.
Table 29 Problem 2 Simulation Control Parameters
Parameter
Radius of the NAPL source,
RS
Radius multiplication factor
Maximum NAPL saturation in
the lens, S0(max)
Simulation ending time
Maximum solution time step
Minimum time between printed
time steps and mass balance
checks
Rationale
From the problem definition
Suggested value
Estimated from the NTHICK utility
described in Appendix 7
A time much greater than that expected
for the NAPL lens to form
Limit of approximately less than 1 month
The model can produce output on very
small time intervals, such information is
of little usefulness.
Value
2.0 meters
1.001
0.3260
2500 days
20 days
0.1 days
OILENS Simulation Ending Criterion

     The fourth option, "contaminant leached from lens," is chosen for the ending condition as this is the
only option that allows the HSSM-T model to be run. The fraction of mass remaining is chosen to be 0.01.
The OILENS portion of HSSM-KO will terminate when less than 1% of the mass that has entered the lens
over the length of the simulation  remains in the lens.  The other 99%  will have been  leached into the
ground water.  The chemical constituent will still exist below the source in the vadose zone. This amount
of chemical is contained in the NAPL phase as residual saturation, and it never enters the lens.
                                             81
[Section 5 Example Problems]

-------
HSSM-T Model Parameters

     Many previously entered parameters are used by HSSM-T. The remaining parameters are listed in
Table 30.
Table 30 Problem 2 HSSM-T Model Parameters
Parameter
Percent maximum contaminant
radius
Minimum output concentration
Beginning time
Ending time
Time increment
Rationale
The radius that occurs when the mass
flux to the aquifer is maximum should be
used. The value 101 is a flag that
triggers this selection.
The minimum concentration that HSSM-
T will report. A non-zero value is
required for HSSM-T to function
properly.
Arbitrary value that will be overridden by
a successful HSSM-T simulation
Arbitrary value that will be overridden by
a successful HSSM-T simulation
A 50-day time increment usually
produces smooth concentration history
curves
Value
101
0.001 mg/l
1 00 days
5000 days
50 days
NAPL Lens Profiles

     HSSM can output profiles at various times during the simulation. The profiles represent the amount
of NAPL in the vadose zone pore space and the configuration of the NAPL lens.   Because the motion of
the  gasoline is relatively rapid, the profiles should be clustered toward the release time.  To catch the
NAPL as it moves through the sandy vadose zone, for example, profile times less than  about 1 day are
needed.  In this example, however, the lens configuration is of more interest and seven somewhat later
profile times are selected: 25, 50, 75, 100, 125, 150 and 200 days.

Receptor Well Locations

     The six receptor locations for this simulation are at 25, 50, 75, 100, 125 and 150 meters away from
the  center of the source, taken longitudinally in the flow direction.  The completed dialog box is shown in
Figure 39.
[Section 5  Example Problems]
82

-------
— . Simulation Parameters
SIMULATION CONTROL PARA
Radius of NAPL lens source (m) 	
Radius multiplication factor 	
Max NAPL saturation in NAPL lens . .
Simulation ending time (d) 	
Maximum solution time step (d) 	
Minimum time between printed time
steps (d)
METERS
2.000
1.001
.3260
2500
20.00

.1000

"OILENS Simulation ending criterion
O User-specified time
O NAPL lens spreading stops
O Max contaminant mass flux into aquifer
(•) Contaminant leached from lens


HSSM-T MODEL PARAME'
Percent max. contam't radius (H) 	
Minimum output conc'n (mg/L) 	
Beginning time (d) 	
Ending time (d) 	
Time increment (d) 	
— — — —
.1000E-01
FERS
101.0
.1000E-02
100.0
5000.
50.00
Data file:
C:\HSSM\X2BT.DAT
Q Enable range checking
NAPL LENS PROFILES 1
Enter time (d) for 2
each of up to 3
1 0 profiles
5
Number of . 	 , 6
profiles |_Z 	 | 7
0
9
10
RECEPTOR WELL x fm,
LOCATIONS *lm)
1 25.00
Enter coordinates 2 50.00
for each of up to 3 __ nn
4 100.0
Miimhetr nf u*nll» ** ' 25.0
|e 1 E iso.o

1 (OKI 1
| Cancel

25.00
50.00
75.00
100.0
125.0
150.0
200.0



Y(m)
.0000
.0000
.0000
.0000
.0000
.0000


Figure 39  Problem 2 completed Simulation Control dialog box parameters
     Each graph generated by HSSM for this data set was shown previously in Figure 23 to Figure 28.
This example shows typical behavior for gasoline releases.  There is relatively rapid flow and transport in
the vadose zone followed  by the formation and decay of a NAPL lens at the water table.  Subsequent
leaching of the chemical constituent of the NAPL (benzene) causes contamination of the aquifer. The time
scales for lens formation and decay,  leaching, and transport to the 150 m receptor are on the order of 1
year, 4 years, and 11 years, respectively.
                                              83
[Section 5 Example Problems]

-------
Section 6  Contents of the Output Files

     Although two graphical user interfaces are provided with HSSM, much of the useful and necessary
information produced by the model is not contained on the graphs produced by these software packages.
The main output files of the HSSM-KO and HSSM-T programs contain a summary of the input data and
model results. The following tables describe each part of these files, along with excerpts from the output
files. Several complete sets of output files are distributed on the  HSSM-2 diskette.


6.1  HSSM-KO Output File

     Table 31 outlines the contents of the HSSM-KO output file which has the extension .HSS. The output
file consists of a series of tables which contain the results from the simulation.
Table 31 HSSM Main Output File Contents
Table Title
Input Data
Location of the Oil Front
Location of the Constituent
Front
OILENS Model Output-Oil
Lens Description
OILENS Model Output--
Aqueous Contaminants
Saturation and Concentration
Profile
Radial Profile Through the
Lens
KOPT/OILENS Postprocessing
HSSM--Run Information
Contents
1 . Echo print of the input data.
2. Parameters calculated directly from input data.
3. Water/air and NAPL/air capillary pressure curves used in the
model.
Position of the NAPL front during the simulation.
Position of the chemical constituent of interest during the
simulation.
Description of the NAPL lens during the simulation.
Description of leaching of aqueous contaminants during the
simulation.
Variation with depth of vadose zone saturations and
concentrations at a user-specified time.
Variation with radius of the top and bottom of the OILENS at a
user-specific time.
Summary information from the simulation.
Information on the numerical techniques used in the simulation.
If the model executes with no catastrophic errors,  then the HSSM-KO output file is ended with the
message:
*********************
SUCCESSFUL  EXECUTION
[Section 6 Contents of the Output Files]
84

-------
Each component of the output file is described in further detail below. For each table in the output file, the
column headings and their meanings are described. An excerpt from the .HSS file follows each description.
Table 32 Input Data
Purpose: To provide an echo printing of the input data set and print out the results of preliminary
calculations
Section
1
2
3
Contents
Echo printing of input data so the user can assure that
values have been entered.
the intended parameter
Model parameters calculated from the input data.
Air/water and air/NAPL capillary pressure curves used
in the simulation.
           **************************************************
           HSSM
HYDROCARBON SPILL SIMULATION MODEL
           **************************************************
           KOPT
           OILENS
           TSGPLUME
           ***********!
KINEMATIC  OILY POLLUTANT TRANSPORT
RADIAL OIL LENS MOTION
TRANSIENT  SOURCE GAUSSIAN  PLUME
  *********************************
           Benzene transport  from 1500 gal gasoline spill
            1.15% benzene  in  gasoline
            sandy soil, properties from Carsel  and Parrish
                INPUT DATA
                DATA FILES:
                 HSSM-KO INPUT:      x2bt.dat
                 HSSM-KO OUTPUT:     x2bt.HSS
                 HSSM-KO PLOT  1:     x2bt.PL1
                 HSSM-KO PLOT  2:     x2bt.PL2
                 HSSM-KO PLOT  3:     x2bt.PL3
                 HSSM-T INPUT:       x2bt.PMI
                 HSSM-T OUTPUT:      x2bt.TSG
                 HSSM-T PLOT:        x2bt.PMP
                INTERFACE FLAG              = D
                WRITING CRITERIA
                KOPT RUN FLAG
                DISSOLVED CONSTITUENT FLAG  =
                OILENS RUN FLAG              =
                TSGPLUME RUN FLAG
                              1
                              1
                              1
                              1
                              1
                CONSTANTS & MATRIX PROPERTIES.
                SAT.  VERT. HYD.CONDUCTIVITY =
                RATIO OF HORIZONTAL TO
                VERTICAL CONDUCTIVITY
                     7.100
                  =  2.500
(M/D)

(*)
                                        85
                       [Section 6 Contents of the Output Files]

-------
RELATIVE PERMEABILITY INDEX =
POROSITY
RESIDUAL WATER SATURATION
VAN GENUCHTEN ' S N
WATER EVENT CHARACTERISTICS
DYNAMIC VISCOSITY
DENSITY
RAIN TYPE : 1-FLUX 2 -SAT.
WATER FLUX OR SATURATION
MAX KRW DURING INFILTRATION =
DEPTH TO WATER TABLE =
2
.4300
.1000
4.500

1.000
1.000
1
.1400E-02
.5000
10.00
(*)
(*)
(*)
(*)

(CP)
(G/CC)
(*)
(M/D OR *)
(*)
(M)
POLLUTANT EVENT CHARACTERISTICS 	
DYNAMIC VISCOSITY
DENSITY
RESIDUAL NAPL SATURATION
OIL LOADING TYPE
CAPILLARY SUCTION PARAMETERS
VAN GENUCHTENS ALPHA
WATER SURFACE TENSION
OIL SURFACE TENSION
FLUX LOADING RATE =
BEGINNING TIME
ENDING TIME
.4500
.7200
. 5000E-01
1

2.680
65.00
35.00
.4522
.0000
1.000
(CP)
(G/CC)
(*)
(*)

(1/M)
(DYNE /CM)
(DYNE/CM)
(M/D)
(D)
(D)
DISSOLVED CONSTITUENT PARAMETERS -
INITIAL CONC. IN NAPL
NAPL/WATER PARTITION COEF .
SOIL/WATER PARTITION COEF. =
SOIL/WATER (HYDROCARBON)
BULK DENSITY
OILENS SUBMODEL PARAMETERS
RADIUS OF POLLUTANT SOURCE =
RADIUS MULTIPLYING FACTOR
THICKNESS OF CAP. FRINGE
AQUIFER'S VERT DISPERSIVITY =
GROUNDWATER GRADIENT
NAPL RESIDUAL IN AQUIFER
MAX NAPL SATURATION IN LENS =
WATER SOLUBILITY CONTAMINANT=
WATER SOLUBILITY OF OIL
SIMULATION PARAMETERS ....
SIMULATION ENDING TIME
MAXIMUM RKF TIME STEP
MIN. TIME BETWEEN PRINTING =
ENDING CRITERIA
FACTOR FOR ENDING CRITERIA 4=
PROFILES 	 	
NUMBER OF PROFILES
AT TIMES :
25.0000 50.0000
100.0000 125.0000
200 . 0000
8208.
311. 0
.8300E-01
.8300E-01
1.510

2.000
1.001
.1000E-01
.1000
.1000E-01
.1500
.3260
1750 .
10.00

2500 .
20.00
.1000
4
.1000E-01

7

75.0000
150.0000

(MG/L)
(*)
(L/KG)
(L/KG)
(G/CC)

(M)
(*)
(M)
(M)
(*)
(*)
(*)
(MG/L)
(MG/L)

(D)
(D)
(D)
(*)
(*)

(*)
(D)



                   TSGPLUME  MODEL PARAMETERS.
                   LONGITUDINAL  DISPERSIVITY
          10.00
(M)
[Section 6  Contents of the Output Files]
86

-------
                TRANSVERSE DISPERSIVITY         1.000      (M)
                PERCENT MAX.  RADIUS             101.0      (M)
                MINIMUM OUTPUT  CONG.            .1000E-02  (MG/L)
                CONSTITUENT HALF LIFE           .0000      (D)
                NUMBER OF RECEPTOR LOCATIONS             6  (*)
                BEGINNING TIME  (D)               100.0      (D)
                ENDING TIME  (D)                  5000.      (D)
                TIME INCREMENT  (D)               50.00      (D)
                AQUIFER THICKNESS (M)           15.00      (M)

                RECEPTOR LOCATIONS
                               X          Y
                       25.00       .0000
                       50.00       .0000
                       75.00       .0000
                       100.0       .0000
                       125.0       .0000
                       150.0       .0000
                LEGEND

                 (*)
                 (M)
                 (D)
                 (CP)
                 (M/D)
           DIMENSIONLESS OR NOT  APPLICABLE
           METERS
           DAYS
           CENTIPOISE  1.0 CP  =  0.01 GR/CM/SEC
           METERS  PER DAY
                 (DYNE/CM) DYNE  PER CENTIMETER
                 (MG/L)     MILLIGRAMS PER LITER
                 (L/KG)     LITERS  PER KILOGRAM SOIL
                 (G/CC)     GRAMS PER CUBIC CENTIMETER
                ***END OF INPUT  DATA***
Parameters calculated directly from the input data follow the echo printing of the input data set:
CALCULATED PARAMETERS	
SAT VERT NAPL  CONDUCTIVITY =
AREA  OF THE SOURCE
APPROX.  BROOKS AND COREY
LAMBDA
AIR ENTRY HEAD
TRAPPED AIR SATURATION      =
WATER SATURATION
WATER FLUX
MAX.  OIL CONDUCTIVITY
POLLUTANT VOLUME  FLUX
TOTAL OIL LOADING,  VOL/AREA =
TOTAL OIL MASS
TOTAL CONSTITUENT MASS      =
11.36
12 .57

2 . 064
.2759
.1442
.2049
.1400E-02
3.157
 .4522
.4522
4091.
46.64
                                                             (M/D)
                                                             (*)
                                                             (M)
                                                             (*)
                                                             (*)
                                                             (M/D)
                                                             (M/D)
                                                              (M/D)
                                                             (M)
                                                             (KG)
                                                             (KG)
                                         87
                                    [Section 6 Contents of the Output Files]

-------
The estimated capillary pressure curves for air/water and air/NAPL follow the input data in the name.HSS
file:
            WATER-AIR,  NAPL-AIR CAPILLARY  PRESSURE  CURVE
WATER or NAPL C
SATURATION I
.1200
.1400
.1600
.1800
.2000
.2200
.2400
.2600
.2800
.3000
.3200
.3400
.3600
.3800
.4000
.4200
.4400
.4600
.4800
.5000
.5200
.5400
.5600
.5800
.6000
.6200
. 6400
.6600
.6800
.7000
.7200
.7400
.7600
.7800
. 8000
.8200
.8400
.8600
.8800
.9000
.9200
.9400
.9600
.9800
1.0000
:APILLARY
iEAD (CM WATER)
1.7438
1.2464
1.0242
.8909
.7997
.7321
.6794
.6368
.6015
.5716
.5458
.5233
.5034
.4856
.4697
.4552
.4420
.4300
.4189
.4086
.3990
.3901
.3818
.3740
.3667
.3598
.3533
.3471
.3413
.3357
.3304
.3254
.3206
.3160
.3116
.3073
.3033
.2994
.2957
.2920
.2886
.2852
.2820
.2789
.2759
CAPILLARY
HEAD (CM NAPL)
1.3041
.9322
.7659
.6663
.5980
.5475
.5081
.4763
.4499
.4275
.4082
.3913
.3765
.3632
.3512
.3404
.3306
.3216
.3132
.3056
.2984
.2918
.2856
.2797
.2743
.2691
.2642
.2596
.2552
.2511
.2471
.2433
.2397
.2363
.2330
.2298
.2268
.2239
.2211
.2184
.2158
.2133
.2109
.2086
.2063
[Section 6  Contents of the Output Files]
88

-------
Table 33 Location of the NAPL Front
Purpose: A summary of the NAPL distribution in the vadose zone.
Column
1
2
3
4
5
6
7
8
Column Heading
Step
Time (D)
Depth (M)
Saturation
Flux (M/D)
Runoff (KG)
Mass (KG)
Ponding (M)
Contents
The number of time steps completed. These
numbers are usually not consecutive, because a
minimum printing interval should be chosen.
The time in days since the beginning of the
simulation.
The depth of the sharp front at the leading edge
of the infiltrating NAPL.
The NAPL saturation at the front; NAPL
saturations behind the front are often lower than
this value, as can be seen on the saturation
profiles.
NAPL flux at the front.
Runoff is produced when a NAPL flux boundary
condition is specified and the flux is greater than
the maximum dynamic flux allowed by the Green-
Ampt model with zero ponding head.
NAPL mass added to the profile per square
meter.
The surface ponding depth of NAPL.
NOTE:   This output table is produced only up until a NAPL lens forms.  At that time the OILENS model
         output is produced.
                                             89
[Section 6 Contents of the Output Files]

-------
        **************************************************
                      LOCATION OF THE NAPL FRONT
        **************************************************
        Benzene  transport from 1500 gal gasoline  spill
         1.15% benzene in gasoline
         sandy soil,  properties from Carsel  and Parrish
                                        NAPL
STEP
1
4
5
7
8
9
10
11
13
23
29
33
38
41
43
45
47
49
50
51
52
53
54
55
TIME
(D)








1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
3
.0000
.2000
.3000
.5000
.6000
.7000
. 8000
.9000
.0107
.1182
.2248
.3330
.4399
.5691
.6771
.8050
.9668
.1530
.2657
.3909
.5290
.6809
.8478
.0310
DEPTH SATURATION
(M) (*)

.

1.
1.
1.
2.
2.
2.
2.
3.
3 .
3.
4.
4.
4.
4.
4.
4.
5.
5.
5.
5.
5.
{Intermediate results
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
7
7
8
8
9
10
11
12
13
14
15
16
18
19
21
22
24
. 0717
.6604
.2492
. 8379
.5411
.3414
. 1417
.0723
.1191
.1658
.3753
.7325
.0897
.4469
. 0820
.9444
.6391
7 .
7 .
7 .
7 .
7 .
8 .
8.
8.
8.
8.
8.
9.
9.
9.
9.
9.
9.
0000
5315
7972
3287
5944
8602
1259
3917
6858
9715
2548
5423
8024
0598
2426
4325
6423
8527
9677
0866
2086
3332
4605
5905
omitted}
3052
4685
6205
7628
9217
0901
2470
4171
5947
7601
9379
1231
2953
4562
6370
8283
9905
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3957
.3710
.3472
.3320
.3175
.3029
.2895
.2826
.2758
.2692
.2627
.2564
.2503

.1892
.1848
.1809
.1774
.1736
. 1697
.1663
.1626
.1590
.1557
.1524
.1490
.1460
.1433
.1403
.1372
.1348
FLUX
(M/D)
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.4522
.3510
.2703
.2266
.1900
.1577
.1317
.1197
.1087
.0986
.0894
.0811
.0736

.0234
.0212
.0194
.0179
.0163
.0148
.0136
.0123
.0112
.0102
.0093
.0084
.0077
.0071
.0064
.0058
.0054
RUNOFF MASS
(KG) (KG)
PONDING
(M)
.0000 .0000
.0000
.0000
.0000
.0000
.0000
.0000
. 0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000

.0000
.0000
.0000
.0000
. 0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
. 0000
.0000
.0000
.0000
818.3
1227.
2046.
2455.
2864.
3273.
3682.
4091.
4091.
4091.
4092.
4092.
4091.
4091.
4091.
4091.
4091.
4091.
4091.
4091.
4091.
4091.
4091.

4089 .
4089.
4089.
4089.
4089 .
4089 .
4089 .
4089.
4089.
4089.
4089.
4088 .
4088.
4088.
4087.
4087.
4086 .
.0000
.0000
.0000
.0000
.0000
. 0000
.0000
.0000
. 0000
.0000
.0000
. 0000
. 0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000

.0000
.0000
. 0000
.0000
. 0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
. 0000
.0000
. 0000
[Section 6 Contents of the Output Files]
90

-------
Table 34 Location of the Constituent Front
Purpose: A summary of the vadose zone distribution of the dissolved constituent.
Column
1
2
3
-*•»
4
5
6
Column Heading
Step
Time
Depth-Upper
Depth- Lower
Cone-water
Mass
Contents
The number of time steps completed.
The time in days since the beginning of the
simulation.
The depth in meters of the leading edge of the
constituent.
The depth in meters of the trailing edge of the
constituent
The water phase concentration of the constituent
at the leading edge.
The total mass of the constituent in the vadose
zone.
NOTE: This output table is produced only up until a NAPL lens forms.  At that time the OILENS model
output takes over.
                                            91
[Section 6 Contents of the Output Files]

-------
         **************************************************

                      LOCATION OF THE  CONSTITUENT FRONT
        Benzene transport from 1500  gal  gasoline spill
          1.15% benzene in gasoline
          sandy soil,  properties from Carsel  and Parrish
                                    CONSTITUENT
STEP
4
5
7
8
9
10
11
13
23
29
33
38
41
43
45
47
49
50
51
52
53
54
55
56
57
TIME







1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
3
3
3
.2000
.3000
.5000
.6000
.7000
.8000
.9000
.0107
.1182
.2248
.3330
.4399
.5691
.6771
.8050
.9668
.1530
.2657
.3909
.5290
.6809
.8478
.0310
.2321
.4528
DEPTHS CONC- WATER
LOWER UPPER

.
1.
1.
1.
2.
2.
2.
2.
3.
3.
3.
4.
4.
4.
4.
4.
4.
5.
5.
5.
5.
5.
5 .
5 .
{Intermediate results
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
6
6
7
7
8
8
9
10
11
12
13
14
15
16
18
19
21
.0533
.5365
.0717
.6604
.2492
.8379
.5411
.3414
.1417
.0723
.1191
.1658
.3753
.7325
.0897
.4469
.0820
6.
7.
7 .
7 .
7 .
7 .
7 .
8.
8.
8.
8.
8.
8.
9.
9.
9.
9.
5294
7941
3235
5882
8529
1176
3823
6753
9598
2419
5283
7864
0416
2226
4107
6184
8265
9403
0578
1784
3015
4273
5556
6864
8197
omitted}
9350
0879
2452
4057
5551
6949
8510
0163
1702
3370
5113
6733
8475
0288
1973
3547
5316
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0001
.0001
.0001
.0001
.0002
.0002
.0002
.0003
.0003
.0003
.0003
.0004
.0004
. 0005
.0005

.0010
.0011
.0012
.0013
.0015
.0016
.0017
.0019
.0021
.0022
.0025
.0027
.0029
.0032
.0035
.0037
.0041
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26

26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920

.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
MASS
9.
13
23
27
32
37
41
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46

46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
46
329
.99
.32
.99
.65
.32
.98
.64
.65
.65
.65
.65
.65
.65
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64

.63
.63
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.61
.61
[Section 6 Contents of the Output Files]
92

-------
Table 35 OILENS Model Output-NAPL Lens Description
Purpose: A summary of the NAPL lens configuration.
Column
1
2
3
4
5
6
7
8
9
Column Heading
Step
Time
Lens Height
Lens Radius
Lens Volume
Residual Volume
Volume Losses
Cumulative Inflow
Percent Volume Error
Contents
The number of time steps completed.
The time in days since the beginning of the
simulation.
The height in meters of the NAPL lens above the
spreading zone.
The radius in meters of the NAPL lens.
The volume of NAPL in the lens in cubic meters.
The volume of NAPL in cubic meters trapped at
residual above and below the lens
The cumulative volume of NAPL lost to
dissolution in cubic meters.
The cumulative volume inflow of NAPL to the
lens in cubic meters.
The percent error in calculated NAPL volume as
compared with the cumulative NAPL inflow to the
lens. This volume balance does not include
NAPL in the vadose zone.
93
[Section 6  Contents of the Output Files]

-------
                **************************************************
                *     OILENS MODEL OUTPUT--OIL LENS  DESCRIPTION   *
                **************************************************
                Benzene transport from 1500 gal gasoline spill
                 1.15% benzene in gasoline
                 sandy soil, properties from Carsel and Parrish
   STEP
         LENS     LENS     LENS
 TIME    HEIGHT   RADIUS   VOLUME
(DAYS)   (METERS)  (METERS)   (CU.M.)
RESIDUAL VOLUME    CUM.     PERCENT
VOLUME   LOSSES    INFLOW   VOLUME
(CU.M.)   (CU.M.)   (CU.M.)   ERROR
          *** OIL  FILLING CAPILLARY FRINGE
          *** TIME
          *** OIL  SATURATION IN LENS
          *** CAPILLARY FRINGE OIL THICKNESS
                                          24.6391
                                            .3260
                                            .0100
85
93
95
96
97
98
102
115
118
120
24.90
25.01
25.13
25.27
25.42
25.68
25.79
25.92
26.05
26.21
. 0000
.0011
.0022
.0035
.0047
.0069
.0077
.0086
.0096
.0107
2.00
2.02
2.05
2 . 08
2.10
2.15
2.17
2.20
2.22
2.25
{Intermediate results omitted}
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
807.00
827.00
847.00
867.00
887 .00
907.00
927.00
947.00
967.00
987 . 00
1007.00
1027.00
1047 . 00
1067.00
1087.00
1107.00
.0045
. 0044
.0042
.0041
.0040
.0039
.0038
.0036
.0035
.0035
.0034
. 0033
.0032
.0031
.0030
.0030
16.35
16.44
16.52
16.59
16.67
16.74
16.81
16.87
16.94
17.00
17.05
17 .11
17.16
17.21
17.26
17.31
                                         .02
                                         .02
                                         .03
                                         .04
                                         .05
                                         .07
                                         .08
                                         .08
                                         .09
                                         .10
                                       1.99
                                       1.99
                                       1.98
                                       1.97
                                       1.97
                                       1.96
                                       1.96
                                       1.95
                                       1.95
                                       1.94
                                       1 .94
                                       1.93
                                       1.93
                                       1.92
                                       1.92
                                       1.91
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .00
                                        .58
                                        .59
                                        .60
                                        .60
                                        . 61
                                        .62
                                        .62
                                        .63
                                        .63
                                        .64
                                        .64
                                        .65
                                        . 65
                                        .65
                                        .66
                                        .66
             .00
             .00
             .00
             .00
             .00
             .00
             .00
             .00
             .00
             .00
             .09
             .09
             .09
             .10
             . 10
             .10
             .11
             . 11
             .11
             .12
             .12
             .12
             .13
             .13
             .13
             .14
 .02
 .02
 .03
 .04
 .05
 .07
 .08
 .08
 .09
 .10
  66
  67
  67
  67
  68
  68
  68
  69
  69
  69
  69
2.70
2.70
2.70
2.70
2.71
.20
.14
.11
.08
.06
.03
.03
.03
.02
.02
.04
.05
.06
.07
.08
.10
.11
.13
.14
.16
.18
.19
.21
.23
.25
.27
[Section 6 Contents of the Output Files]
                              94

-------
Table 36 OILENS Model Output-Aqueous Contaminants
Purpose: A summary of the OILENS output for the chemical constituent of the hydrocarbon.
Column
1
2
3
4
5
6
7
8
9
Column Heading
Time
Species Radius
NAPL Dissolution
Species Dissolution
Species Dissolution
Mass Degraded
Mass Remaining
Water Concentration
Percent Mass Balance Error
Contents
The time in days since the beginning of the
simulation.
The effective radius for the constituent in meters.
The dissolution rate of the NAPL in kilograms per
day.
The dissolution rate of the constituent in
kilograms per day.
The cumulative mass of the constituent dissolved
in kilograms.
The cumulative mass of the constituent degraded
in kilograms.
The mass of the constituent remaining in the lens
in kilograms.
The water phase concentration in milligrams per
liter of the constituent in contact with the ground
water.
The calculated percent error in the constituent
mass, based on the mass influx to the lens.
95
[Section 6  Contents of the Output Files]

-------
                *     OILENS MODEL OUTPUT--AQUEOUS CONTAMINANTS   *
                **************************************************
                Benzene transport from 1500 gal gasoline spill
                 1.15% benzene in gasoline
                 sandy soil, properties from Carsel  and Parrish
TIME
( DAYS )
25
25
26
26
26
26
26
26
26
27
27
27
27
28
.83
.96
.12
.29
.40
.52
.65
.79
.96
.15
.36
.58
.81
.06
SPECIES
RADIUS
(M)
2
2
2
2
2
2
2
2
2
2
2
2
2
2
.00
.03
.06
.09
.10
.13
.15
. 17
.20
.24
.27
.31
.34
.39
OIL
DISSOL.
(KG/D)
.525E-02
.531E-02
.540E-02
.550E-02
.556E-02
.563E-02
.571E-02
.579E-02
.589E-02
.600E-02
.613E-02
.626E-02
.641E-02
. 655E-02
SPECIES
DISSOL.
(KG/D)
.551E-04
.131E-02
.269E-02
.387E-02
.450E-02
.517E-02
.579E-02
.645E-02
.713E-02
.782E-02
.851E-02
.920E-02
.983E-02
.105E-01
SPECIES MASS MASS
DISSOL. DEGRADED REMAINING
(KG) (KG) (KG)
.00
.00
.00
.00
.00
.00
.00
.00
.00
.01
.01
.01
.01
.01
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.07
.15
.24
.29
.35
.41
.48
.56
.65
.75
.85
.96
1.07
WATER
CONG.
(MG/L)

2
5
7
9
10
11
12
13
14
15
16
16
17
.12
.80
.60
.87
.05
.24
.27
.33
.36
.34
.24
.07
.77
.44
P.C.
MASS
ERROR
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
{Intermediate  results omitted}
607 .
627.
647.
667 .
687.
707.
727.
747 .
767.
787 .
807 .
827.
847 .
867.
887.
907.
927.
947 .
967.
987.
1007
1027
1047
1067
1087
1107
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0




.

15
15
15
15
15
15
15
15
16
16
16
16
16
16
16
16
16
16
16
16
16
16
16
17
17
17
.09
.22
.35
.47
.58
.69
.80
.90
.00
. 09
.18
.26
.34
.42
.49
.56
.63
.69
.76
.82
.88
.93
.98
.04
.09
.13
.102
.104
.105
.106
. 108
. 109
.110
.111
.112
.113
.114
.115
.116
.117
. 118
.119
.120
. 120
.121
.122
.122
.123
.124
.124
.125
. 125
. 647E-02
.585E-02
.530E-02
.483E-02
.442E-02
.406E-02
.375E-02
.347E-02
.323E-02
.302E-02
.283E-02
.267E-02
.252E-02
.238E-02
.226E-02
.216E-02
.206E-02
.197E-02
.189E-02
.181E-02
.175E-02
.168E-02
.163E-02
.157E-02
.152E-02
.148E-02
20
20
20
20
20
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
21
.53
.65
.76
.87
.96
.04
.12
.19
.26
.32
.38
.44
.49
.54
. 58
.63
.67
.71
.75
.79
.82
.86
.89
.92
.95
.98
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.50
.45
.40
.36
.33
.30
.27
.25
.23
.21
.20
. 19
.17
.16
.15
.15
.14
.13
.13
.12
.11
.11
.11
.10
.10
.09
.64
.57
.51
.46
.41
.38
.34
.31
.29
.27
.25
.23
.22
.21
.19
.18
.17
.17
.16
.15
.14
.14
.13
.13
.12
.12
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.0
[Section 6 Contents of the Output Files]
96

-------
Table 37 Saturation and Concentration Profile
Purpose: A summary of the saturations and concentrations in the vadose zone.
Column
1
2
3
4
Column Heading
Depth
Saturation
Concentration (water)
Dissolved NAPL Concentration
Contents
The depth in meters.
The NAPL phase saturation.
The dissolved constituent concentration in the
water phase in milligrams per liter.
The dissolved NAPL concentration in the
phase in milligrams per liter.
water
NOTE:  After an NAPL lens forms this profile is truncated at the top of the NAPL lens.  A radial profile
of the NAPL lens is then produced.
           SATURATION AND CONCENTRATION PROFILE AT     25.0000
           **************************************************

           Benzene transport from 1500  gal gasoline  spill
            1.15% benzene in gasoline
            sandy soil,  properties  from Carsel and Parrish
                   DEPTH
                                    SAT.   CONG.(WATER)  DISSOL. NAPL  CONC














1
2
2
3
3
3
3
3
4
5
5
6
6
.0000
.0000
.0001
.0006
.0014
.0024
.0034
.0042
.0047
.0049
.0049
.0898
.4360
.9960
.6731
.3501
.9101
.2563
.3412
.3412
.4263
.7730
.3338
.0119
.6899
.2507
.5975
.0500
.0500
.0500
.0500
.0500
.0501
.0501
.0501
.0501
.0501
.0501
.0524
.0618
.0725
.0814
.0885
.0936
.0965
. 0972
.0972
.0978
.1005
.1044
.1089
.1130
.1162
.1181










26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
26.
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
3920
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
.0000
.0000
.0000
.0000
.0000
. 0000
.0000
.0000
.0000
.0000
. 0000
.0000
.0000
. 0000
.0000
. 0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
                                        97
[Section 6 Contents of the Output Files]

-------
                    7 .
                    7.
6.6825
6.6825
6.7646
 .0995
 .6411
8.2959
8.9507
9.4923
9.8272
9.9093
9.9093
9.9114
9.9196
9.9330
9.9492
9.9654
9.9787
9.9870
9.9890
1186
1186
1190
1208
1235
1267
1296
1320
1335
1338
1338
1338
1338
1339
1340
1340
1341
1341
1341
26
26
26
26
26
26
26
26
26
26









.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.3920
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
.0000
          KOPT  PROFILE MASS PER UNIT AREA:
          NAPL                            (KG/M/M)   323.8
          DISSOLVED NAPL                 (KG/M/M)   .2132E-01
          CONSTITUENT                    (KG/M/M)   3.708
          KOPT  PROFILE TOTAL MASS:
          CONSTITUENT
          NAPL
                          (KG)
                          (KG)
46.60
4069.
[Section 6 Contents of the Output Files]
                    98

-------
Table 38 Radial Profile Through the NAPL Lens
Purpose: A radial description of the NAPL lens
Column
1
2
3
4
5
Column Heading
Radius
Current NAPL Lens-Depth of
Top of Lens
Current NAPL Lens-Depth of
Lens Bottom
Maximum Extent of NAPL
Lens-Depth of Top of Lens
Maximum Extent of NAPL
Lens-Depth of Top of Lens
Contents
Radial distance in meters.
The depth in meters from the ground surface to
the top of the current NAPL lens.
The depth in meters from the ground surface to
the bottom of the current NAPL lens.
The depth in meters from the ground surface to
the top of the thickest lens that has occurred
previous to this time. The NAPL is trapped at the
vadose zone residual between the depths for
columns 2 and 4.
The depth in meters from the ground surface to
the bottom of the thickest lens that has occurred
previous to this time. The NAPL is trapped at the
aquifer residual between the depths for columns
3 and 5.
99
[Section 6  Contents of the Output Files]

-------
      **************************************************
      *  RADIAL PROFILE THROUGH OIL LENS
      **************************************************
      TIME                 =    25.0000
      LENS RADIUS          =     2.0213
      DEPTH TO WATER TABLE =    10.0000

                          CURRENT OIL LENS          MAXIMUM EXTENT OF OIL LENS
        RADIUS         DEPTH OF        DEPTH OF        DEPTH OF        DEPTH OF
           .0000
          2.0000
          2.0011
          2.0021
          2.0032
          2.0043
          2.0053
          2.0064
          2.0075
          2.0085
          2.0096
          2.0107
          2.0117
          2.0128
          2.0139
          2.0149
          2.0160
          2.0171
          2.0181
          2.0192
          2.0203
          2.0213
                     TOP OF LENS
                                     LENS BOTTOM
9.9890
9.9890
9.9891
9.9891
9.9891
9.9891
9.9892
9.9892
9.9892
9.9893
9.9893
9.9893
9.9894
9.9894
9.9894
9.9895
9.9895
9.9896
9.9896
9.9897
9.9898
9.9900
10.0025
10.0025
10.0024
10.0023
10.0023
10.0022
10.0021
10.0021
10.0020
10.0019
10.0018
10.0017
10.0017
10.0016
10.0015
10.0014
10.0012
10.0011
10.0010
10.0008
10.0006
10.0000
                                                     TOP OF LENS
                    9.9890
                    9.9890
                    9.9891
                    9.9891
                    9.9891
                    9.9891
                    9.9892
                    9.9892
                    9.9892
                    9.9893
                    9.9893
                    9.9893
                    9.9894
                    9.9894
                    9.9894
                    9.9895
                    9.9895
                    9.9896
                    9.9896
                    9.9897
                    9.9898
                    9.9900
                                                                    LENSBOTTOM
10.0025
10.0025
10,0024
10.0023
10.0023
10.0022
10.0021
10.0021
10.0020
10.0019
10.0018
10.0017
10.0017
10.0016
10.0015
10.0014
10.0012
10.0011
10.0010
10.0008
10.0006
10.0000
          CUMULATIVE  INFLUX TO  LENS   17.35
          KOPT AND OILENS  GLOBAL MASS  BALANCES
          TOTAL NAPL MASS  ADDED AT  BOUNDARY   (KG)   4091.
          NAPL MASS RECOVERED  BY MASS  BALANCE (KG)  4086.
          PER CENT ERROR                          -.1285
[Section 6 Contents of the Output Files]
100

-------
6.2 HSSM-T Output File

The HSSM-T output file contains the items shown in Table 39.
Table 39 HSSM-T Output File Summary
Table Title
Input Data
Reduced Input Mass Flux
Aquifer Concentration History
Contents
Echo printing of the input parameter values.
The mass flux history used by HSSM-T. The
input mass flux is reduced to 31 values.
Concentration histories for each receptor
location.
Benzene transport from 1500 gal gasoline  spill
 1.15% benzene  in gasoline
 sandy soil,  properties from Carsel and Parrish
 TSGPLUME

   INPUT DATA:
   HSSM-KO  INPUT DATA FILE   x2bt.dat
   HSSM-KO OUTPUT FILE
   HSSM-T INPUT  FILE
   HSSM-T OUTPUT FILE
   HSSM-T PLOT FILE
     x2bt.HSS
     x2bt.PMI
     x2bt.TSG
     x2bt.PMP
   HSSM ENDING  PARAMETER,  KKSTOP
   INTERFACE  FLAG                D

   LONG. DISPERSIVITY   = 10.00      (M)
   TRANS. DISPERSIVITY  = 1.000      (M)
   VERT. DISPERSIVITY   = .1000      (M)
   SEEPAGE VELOCITY     = .4128      (M/D)
   POROSITY              = .4300      (*)
   AQUIFER THICKNESS    = 15.00      (M)
   RETARDATION  FACTOR
   P.C. MAX RADIUS
   MIN. AQUIFER CONC.
   DECAY COEFFICIENT
1.291      (*)
101.0      (*)
.1000E-02  (MG/L)
.0000      (1/D)
   BEGINNING TIME
   ENDING TIME
   TIME INCREMENT
100 .0
5000.
50.00
(D)
(D)
(D)
                                       101
                       [Section 6  Contents of the Output Files]

-------
    NO.  OBS. WELLS
                                           (*)
    X-LOCATION Y-LOCATION
25.00
50.00
75 . 00
100.0
125.0
150.0
.0000
.0000
.0000
.0000
. 0000
.0000
    RECHARGE RATE
.00 (M/D)
HSSM-KO is capable of producing very large output files, which if used directly in HSSM-T would cause
HSSM-T to execute very slowly.  HSSM-T extracts a reduced mass flux input history from the HSSM-
KO output contained in file *.PMI.  The reduced mass flux input always contains 31 points.
      REDUCED INPUT MASS FLUX
     HISTORY USED FOR COMPUTATION
   1
   2
   3
   4
   5
   6
   7
   8
   9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
TIME
(D)
25.83
45.56
65.30
85.03
104.8
124.5
163 .8
203.2
242.5
281.9
321.2
360.5
399.9
439.2
478 .6
517 .9
557.2
596 . 6
635 .9
675 .3
714.6
753 .9
793 .3
832.6
872 .0
911.3
950.6
990 .0
1029 .
1069.
1108.
MASS FLUX
(KG/D)
. 5510E-04
.3551E-01
.5216E-01
.6225E-01
. 6770E-01
. 6990E-01
.6743E-01
. 6015E-01
.5114E-01
.4203E-01
.3379E-01
.2685E-01
.2122E-01
.1675E-01
.1333E-01
. 1057E-01
. 8479E-02
. 6845E-02
. 5605E-02
.4661E-02
.3942E-02
.3387E-02
.2960E-02
.2628E-02
.2350E-02
.2138E-02
.1955E-02
.1801E-02
. 1674E-02
.1566E-02
.0000
[Section 6 Contents of the Output Files]
         102

-------
   TIME STEP TOO SMALL RELATIVE  TO MASS FLUX DURATION
   MODIFIED TIME STEP        = 108.2      (D)
   MAXIMUM RADIUS             =  17.13       (M)
   MAX. RADIUS  TIME            =  1107.       (D)
   RADIUS AT MAX. FLUX        =  8.510       (D)
   MAX. FLUX TIME              =  124.5       (D)
   EFFECTIVE RADIUS            =  8.510       (M)
   EFFECTIVE AREA              =  227.5       (BT2)
   PENETRATION  THICKNESS      =  1.979       (M)
The HSSM-T results are written out as "aquifer concentration histories" for each of the receptor points.
These consist of times and concentrations calculated for the receptor location.
 AQUIFER CONCENTRATION HISTORIES
     TIME       RECEPTOR LOCATION
                (X       25.00 )
                (  Y          .00 )
30.09
51.74
73.38
84.20
96.65
108.5
119.7
130.4
140.5
150.1
159.7
169.8
172 .4
174.9
175.7
177 . 5
179 . 0
180 . 5
182 .7
186.1
191.5
200.9
217.7
249.2
311.5
370 . 6
426.8
480.2
530.9
579.1
624.8
.1002E-02
1.696
5.004
6.450
7.876
8.974
9.813
10.43
10.86
11 .13
11.30
11.41
11.43
11.44
11.44
11.44
11.44
11.43
11.43
11.40
11.35
11.22
10 .90
9.985
7.751
5.721
4.175
3 .071
2.290
1.744
1.358
                                             103         [Section 6  Contents of the Output Files]

-------
  668.3
  709.6
  748.9
  786.2
  821.6
  855.2
  887.2
  917.5
  946.4
  973.8
  999.8
  1025.
  1048.
  1070.
  1093.
  1116.
  1138.
  1159.
  1179.
  1198.
  1216.
  1233 .
  1250.
  1265.
  1280.
  1294.
  1307.
  1320.
  1332.
  1343 .
  1354.
  1364.
  1374.
  1383.
  1400.
1.085
.8893
.7480
.6436
.5656
.5060
.4586
.4216
.3916
.3665
.3454
.3278
.3128
.3000
.2590
.1526
.7703E-01
.4481E-01
.2868E-01
.1956E-01
.1398E-01
.1035E-01
.7888E-02
.6158E-02
.4906E-02
.3978E-02
.3276E-02
.2735E-02
.2312E-02
.1976E-02
.1706E-02
.1486E-02
.1306E-02
.1157E-02
.9268E-03
[Section 6 Contents of the Output Files]
                       104

-------
References
Abriola, L.M., K. Rathfelder, M.  Maiza,  and S. Yadav,  VALOR  code version 1.0:  A PC code  for
     simulating immiscible contaminant transport in subsurface systems. Electric Power Research Institute,
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Bauman, B.J., Soils contaminated by motor fuels: Research activities and perspectives of the American
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     Lewis Publishers, 3-19, 1989.

Baehr, A. L.  and M. Y.  Corapcioglu, A compositional multiphase model for groundwater contamination
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Bouwer, H,, Rapid field measurements of air entry value and hydraulic conductivity of soil as significant
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Brakensiek,  D. L, R. L. Engleman, and W.  J. Rawls, Variation within texture classes of soil water
     parameters, Transactions of the American Society of Agricultural Engineers.  335-339, 1981.

Brooks, R.  H. and  A.  T.  Corey, Hydraulic  Properties of Porous Media. Colorado  State University
     Hydrology Paper No. 3. Ft. Collins, Colorado, 1964.

Brutsaert, W., Some methods of calculating unsaturated permeability, Transactions of the ASAE. 10(3),
     400-404, 1967.

Carsel  R.F,  and  R.S.  Parrish,  Developing joint  probability distributions of soil  water  retention
     characteristics, Water Resources Research. 24(5), 755-769, 1988.

Gary, J.W.,  J.F.  McBride,  and  C.S. Simmons,  Trichloroethylene  residuals in  the capillary  fringe  as
     affected by air-entry pressures,  Journal of Environmental Quality. 18, 72-77,  1989.

Charbeneau, R. J.,  Liquid moisture  redistribution: Hydrologic simulation and spatial variability, preprint
     NATO Advanced Science Institute. Aries,  France, June, 1988.

Charbeneau,  R.  J.,  Kinematic  models  for  soil  moisture and solute transport, Water Resources
     Research. 20, 699-706, 1984.

Charbeneau, R.J., J.W.  Weaver  and B.K. Lien, The Hydrocarbon  Spill  Screening Model  (HSSIW
     Volume 2: Theoretical Background and Source Codes. US EPA, EPA/600/R-94/039b, 1994.

Charbeneau,  R.J. and  R.G. Asgian,  Simulation of  the transient soil  water content profile for a
     homogeneous bare soil, Water Resources Research. 27(6), 1271-1279, 1991.

Chemical  Information Systems,  Inc.. Information System  for  Hazardous  Organics  in  Water  (ISHOW)
     Database. Towson, Md, 1994.

Cline, P.V., J.J. Delfino,  P.S.C. Rao, Partitioning of aromatic constituents  into water from gasoline and
     other complex solvent mixtures. Environmental Science and Technology. 23, 914-920, 1991.
                                             105                                  [References]

-------
Demond, A.H., and P.V. Roberts,  Effect of interfacial forces on two-phase capillary pressure-saturation
     relationships, Water Resources Research. 23(3), 423-437, 1991.

Farr, A.M., Houghtalen, R.J., and D.B. McWhorter, Volume estimation of light nonaqueous phase liquids
     in porous media, Ground Water 28, 48-56,  1990.

Faust, C.  R., Transport of immiscible fluids within and below the unsaturated zone: A numerical model,
     Water Resources Research. 21(4),  587-596, 1985.

Forsythe,  G.E.,  M.A.  Malcolm, and C.B.  Moler, Computer  Methods for  Mathematical  Computation.
     Prentice-Hall,  Englewood Cliffs, New Jersey, 1977.

Gelhar,  L.  W.,  K.R. Rehfeldt, and C.A. Welty, A critical review  of  data on  field-scale dispersion in
     aquifers, Water Resources Research. 28(7), 1955-1974, 1992.

Green, W. H. and G. A. Ampt, Studies on soil physics, Journal  of Agricultural Science, 4, 1-24, 1911.

Huyakorn,  P.S. and J. Kool, Multiphase Analysis  of  Ground Water. Nonaqueous Phase  Liquid, and
     Soluble Components in Three Dimensions.  Hydrologic Inc., Herndon, Virginia, 1992.

Huyakorn,  P.S.,  M.J.  Ungs,  L.A.  Mulkey and E.A.  Sudicky, A three-dimensional  analytical model for
     predicting leachate migration. Ground Water, 25(5), 588-598,  1982.

Kemblowski, M. W.  and  C. Y. Chiang,   Hydrocarbon thickness fluctuations in monitoring wells, Ground
     Water. 28,244-252, 1990.

Kuppussamy, T., J. Sheng,  J.C.  Parker,  and  R.J.  Lenhard, Finite-element  analysis of multiphase
     immiscible flow through soils, Water Resources Research. 23, 625-631, 1987.

Lenhard, R.J., J.C  Parker,  and S. Mishra, On the  correspondence between  Brooks-Corey and van
     Genuchten models, Journal of Irrigation and Drainage Engineering. 15(4), 744-751, 1989.

Lenhard, R.J., and  J.C.  Parker, Estimation of free hydrocarbon volume from fluid levels in monitoring
     wells, Ground Water. 28 57-67, 1990.

Leverett,   M.C., Capillary behavior in porous  solids,  Transactions  American  Institute  of  Mining
     Engineers. 142, 152-169, 1941

Mercer,  J.W., and  R.M. Cohen,  A review  of immiscible  fluids in the subsurface: properties,  models,
     characterization and remediation, Journal of Contaminant  Hydrology. 6, 107-163, 1990.

Mercer, J.W., D.C. Skipp,  and  D.  Giffin,  Basics  of  Pump-and-Treat  Ground-Water Remediation
     Technology. Robert S.  Kerr  Environmental Research Laboratory,  U.S.  Environmental Protection
     Agency, EPA/600/8-90/003, March  1990.

Parker, J.C., and R.J. Lenhard, Estimation of free hydrocarbon volume from fluid levels in monitoring
     wells, Groundwater. 28, 57, 1990.

Parker, J.C., R.J. Lenhard and T.  Kuppusamy, A parametric model for constitutive  properties governing
     multiphase flow in porous media, Water Resources Research. 23, 618-624, 1987.

Perry, R.H. and C.H. Chilton, Chemical Engineering Handbook. McGraw-Hall, New York, 1973.

[References]                                 106

-------
Rawls,  W.J.,  and D.L. Brakensiek, Prediction  of  soil water properties  for hydrologic modeling,
     Proceedings of Symposium on Watershed Management. 293-299, 1985.

Rawls,  W.J.,  D.L. Brakensiek and B.  Soni,  1983, Agricultural management effects on  soil water
     processes part I: Soil water retention and Green and Ampt infiltration parameters, Transactions of the
     ASAE. 26, 1747-1752.

Reible, D. D., T. H. Illangasekare, D. V.  Doshi, and M. E. Malhiet, Infiltration of immiscible contaminants
     in the unsaturated zone, Groundwater. 28, 688-692,  1990.

Richards, L. A., Capillary conduction of liquids through porous mediums, Physics. 1, 318-333, 1933.

Schiegg, H.O., Considerations on Water, Oil and Air in Porous  Media, Water Science and Technology.
     17, 467-476, 1985.

Schwille, F., Petroleum contamination of the subsoil- A hydrological problem,  The Joint Problems of the
     Oil and Water Industries. 23-54, 1967.

Sims, Ronald C., Judith L. Sims, Steven G. Hansen,  Soil Transport and Fate Database 2.0 and Model
     Management System, June, 1991.

Smith, R.  E., Approximate soil water movement by kinematic  characteristics,  Soil Science Society of
     America Journal. 47, 3-8, 1983.

Smoller, Joel, Shock Waves and Reaction-Diffusion  Equations. Springer-Verlag New York Inc., 1983.

Su, C., and R.H.  Brooks, Water retention measurement for soils, Journal of the Irrigation and Drainage
     Division. 105-112,  1980.

Tauxe, J.D., ShowFlow: A Practical  Interface for Groundwater Modeling. Master's Thesis, The University
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U.  S. Environmental Protection Agency,  Subsurface  Contamination  Reference  Guide.
     EPA 540/2-90/011, October, 1990.

van Dam,  J., The migration of hydrocarbons in a water-bearing stratum, The Joint Problems of the Oil
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van Genuchten,  M. T, A closed-form equation for  predicting the hydraulic conductivity of unsaturated
     soils, Soil Science Society of America Journal.  Vol. 44, 892-898, 1980.

van Genuchten,  M.  Th., F.J.  Leij,  and  S. R.  Yates,  The RETC Code for  Quantifying the Hydraulic
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Weaver, J.W.. Approximate Multiphase  Flow Modeling by  Characteristic Methods.  U.S. EPA,
     EPA/600/2-91/015, 1991.

Weaver, J. W.,  R. J.  Charbeneau, and B.K.  Lien, A screening model for  nonaqueous phase liquid
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-------
Wilson,  J. L, S. H. Conrad, W. R. Mason, W. Peplinski, and  E. Hagan, Laboratory Investigation  of
     Residual Liquid Organics from Spills. Leaks, and the Disposal of Hazardous Wastes in Groundwater.
     US EPA, EPA/600/6-90/004, 1990

Wilson,  J. L. and S. H. Conrad, Is physical displacement of residual hydrocarbons a realistic possibility
     in aquifer restoration?, Proceedings of the NWWA/API Conference on Petroleum Hydrocarbons and
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Wu,  P. C. and H. C. Hottel, Data on fuel and combustion properties, Fossil Fuel Combustion:  A Source
     Book. W. Bartok and A. F. Sarofim, eds., Wiley, New York, 1991.
[References]                                 108

-------
Appendix 1  The  MS-DOS Interface,  HSSM-DOS


     The DOS interface for HSSM  is divided into the three major parts described below.  All are
independent programs that can be executed separately from the DOS prompt. For the convenience of the
user, a simple menu program called HSSM-DOS can be used to run the programs in sequence.  Each
component of the DOS interface is described in detail in the following sections.


1.1  The HSSM-DOS Menu  program

     HSSM-DOS has six options  for running the components of HSSM.   Running the model generally
follows the order of the menu options: creating and editing input data files with PRE-HSSM, running the
simulations with HSSM-KO and  HSSM-T, and plotting the results with  HSSM-PLT.


*
1.
2 .
3 .
4.
5.
6.
ENTER
Table

MENU FOR HSSM
Prepare Input Data Files
View Directory
Run KOPT and OILENS
Run TSGPLUME
Graph Results
Exit
SELECTION (1-6) :
40 HSSM-DOS Menu

*
RUN PRE-HSSM

RUN HSSM-KO
RUN HSSM-T
RUN HSSM-PLT


The following sections introduce each portion of the DOS interface.  Each of these descriptions contains
references to the sections that contain detailed information on using the interface components.


1.2  Data Entry in PRE-HSSM

     PRE-HSSM is a simple interactive preprocessor for the HSSM. PRE-HSSM allows the user to create
data files by means of an interactive set of menus.  The user has no need to know the structure of the data
file. Several input data sets may be created within one session of PRE-HSSM and saved in disk files for
future use  by the HSSM.  Also,  data files created from earlier PRE-HSSM sessions may be read in  and
modified. The parameter names and a brief description of their use are displayed within each menu of the
preprocessor.  The data entry screens are discussed in detail in Appendix 1.8. Although this information
is provided on-line, it does not make the model self-explanatory.  The user must refer to the user's guide
for specific instructions on running the model.  All data entered  in PRE-HSSM must be written to a file
before it is used by HSSM. Any data not saved before exiting PRE-HSSM or starting with a new data set
will be lost. Minimal checking of parameter values is done in PRE-HSSM, so the user must assure  that
the values  are reasonable.
                                           109           [Appendix 1  The MS-DOS Interface]

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1.3  Computation by HSSM-KO and HSSM-T

     The two executables, HSSM-KO and HSSM-T, perform the HSSM simulations. HSSM-KO contains
the KOPT  and  OILENS models and is run first.  Using a previously created input data file, HSSM-KO
creates a formal output file, several plot files and, if the appropriate flags and conditions are set, the input
data file for HSSM-T.  During execution, data is written into several temporary files.  These files are
concatenated upon successful execution into the output and plot files.  The temporary files are then deleted
from the hard disk. If HSSM-KO execution is interrupted, the temporary files remain on the hard disk.  The
program REBUILD can then be used to create as many of the output files as possible.   The TSGPLUME
module of HSSM is run by executing HSSM-T. This program also produces a formal output file and a plot
file.  Directions  for use of the DOS commands for HSSM-KO and HSSM-T are given in Appendix 1.9.


1.4  Graphing of Results in HSSM-PLT

     Although much useful information is contained within the HSSM-KO and HSSM-T formal output files,
graphical display of the model results is  also desirable and useful.  HSSM-PLT allows the display and
printing of  HSSM  output. The plot files which are automatically created by HSSM-KO and HSSM-T are
used by HSSM-PLT to graph the output. Seven different types of graphs are available to the user.  These
graphs are displayed on the screen and may be printed on several types of printers and plotters. Specific
information for using HSSM-PLT is given in appendix 1.10.


1.5  Quick Summary of the DOS Interface Commands

     The following table lists the MS-DOS commands that can be used to run the HSSM without running
the HSSM-DOS menu program. The full details of the procedures are described in the following sections.
[Appendix 1  The MS-DOS Interface]           11 rj

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Table 41 Quick Summary of MS-DOS HSSM Commands
Command
Action
For automated use of the interface:
HSSM-DOS
Activates the DOS menu program which automatically executes
commands listed below.
the
For manual entry of commands at the DOS prompt:
PRE-HSSM
HSSM-KO name.DAT
HSSM-T name.PMI
HSSM-PLT
Executes the interactive input data preprocessor.
Executes the KOPT and OILENS modulates of HSSM, using the
name.DAT data set.
Executes the TSGPLUME module of HSSM, using the name.PMI
data set generated by previous execution of HSSM-KO.
input
Executes the interactive graphical post processor.
Note that HSSM requires a fixed set of file types for its input and output files. HSSM-T and HSSM-PLT
only function properly when the required files types are used.   PRE-HSSM can be used to generate the
required file types automatically.  The required files types are described in Table 15 of Section 4.7.


1.6  System Requirements

     To use the DOS interface, the user should be generally familiar with personal computers, DOS, and
the HSSM model. Also, users are assumed to be knowledgeable about their system hardware (i.e., which
output device is connected to which port).  The hardware and software requirements for using the MS-DOS
interface are listed below.

     n DOS 5.0 or higher
     a 400 kilobytes of free RAM
     a Hard drive (recommended)
Usage of the HSSM-PLT graphics package requires the following :

     n Graphics device that is EGA, VGA, or better.
     n ANSI.SYS driver installed in the CONFIG.SYS file.
The following printers are supported:

     1) EPSON 9-pin, narrow carriage
     2) EPSON 24-pin, LQ series, narrow carriage
     3) EPSON 24-pin, LQ series, wide carriage
     4) NEC Pinwriter, 24-pin, narrow carriage
                                            111
[Appendix 1  The MS-DOS Interface]

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     5) NEC Pinwriter, 24-pin, wide carriage
     6) Okidata, 9-pin, narrow carriage
     7) HP LaserJet/DeskJet - low res.
     8) HP LaserJet/DeskJet - medium res.
     9) HP LaserJet/DeskJet - high res.
     10) HP PaintJet - 2 color, low res.
     11) HP PaintJet - 4 color, med res.
     12) HP PaintJet - 8 color, high res.
     13) HP PaintJet - 16 color, high res.
     14) Postscript printer
     15) HP- HPGL plotter
     16) HP LaserJet III - HPGL/2 mode
     17) Houston Instruments DM/PL plotter
     The amount of available system memory may be checked by entering the DOS 5.0 MEM command.
The amount of memory available for running a DOS program will be displayed. This amount must exceed
400 kbytes in order to run HSSM-KO. Although DOS 5.0 is stated as the minimum level of DOS required
to run HSSM,  earlier versions will likely be adequate; versions below 5.0 have not been tested.
1.7  Installation

     The HSSM software is distributed on two high density diskettes.  A backup copy of these diskettes
should be made and  subsequent work should be performed from the backup copies. The distribution
diskette for HSSM-DOS (HSSM-1-d) contains the files indicated in Table 42.
[Appendix 1  The MS-DOS Interface]            112

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Table 42 Packing List of Files for the HSSM-DOS Interface
File
HSSM-DOS.EXE
PRE-HSSM.EXE
HSSM-KO.EXE
HSSM-T.EXE
HSSM-PLT.EXE
REBUILD.EXE
CONFIG.PLT
SIMPLEX1.FNT
README.TXT
RAOULT.EXE
RAOULT.DAT
SOPROP.EXE
NTHICK.EXE
Purpose
The DOS menu program
Interactive input data processor
The KOPT and OILENS modules of HSSM
The TSGPLUME module of HSSM
Interactive graphical postprocessor
A recovery program for interrupted simulations
Hardware configuration file for HSSM-PLT.EXE
Font file for HSSM-PLT.EXE
Read me file containing distribution information
Utility to perform Raoult's Law Calculation
Default data set for the RAOULT utility
Utility to estimate soil properties with Rawls and Brakensiek's (1985)
regression equations.
Utility to estimate NAPL thickness at the water table
     The following describes how to install the model.  Check the README.TXT file for information on
automated installation procedures, as they are under development as of this writing. To create the HSSM
directory enter the DOS command:

MKDIR C:\HSSM

where HSSM is the name of the HSSM-DOS subdirectory.  With the HSSM-1-d diskette in drive A, copy
all of the files from the diskette into the HSSM directory with the DOS command:

COPY A:\*.*  C:\HSSM

(The program can be installed from another drive, say B, by replacing "A:" in the previous command with
"B: ").   The example problems  and output files contained on diskette HSSM-2 should be installed into
a separate directory.  Create the example problem directory by  entering:

MKDIR C:\HSSM\EXAMPLE

After putting the HSSM-2 diskette  into drive A, the files are copied to this directory by entering:

COPY A:\*.*  C:\HSSM\EXAMPLE

Subdirectories can and should be created for each HSSM simulation.   For example, to create a directory
PROJECT1, enter the command:
                                            113
[Appendix 1  The MS-DOS Interface]

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MKDIR C:\HSSM\PROJECT1

By issuing the DOS command

CD  \HSSM\PROJECT1

before executing HSSM, all the input and output files for the simulation will be in G: \HSSM\PROJECTI.
Installation of both the DOS and Windows interfaces on one machine is discussed in Appendix 9.

     Once HSSM-DOS has been loaded onto your system, you must check the CONFIG.SYS file.  The
HSSM-KO program opens a number of temporary files and CONFIG.SYS must be configured so that a
sufficient number of files may be opened. The CONFIG.SYS on your system needs to include the line

FILES =30

(A number greater than 30 will also work.)  To use HSSM from any directory add c: \HSSM to the path
statement in your AUTOEXEC.BAT file. After modifying these files you must reboot your system to allow the
change to take effect.
[Appendix 1  The MS-DOS Interface]           114

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1.8  Using the PRE-HSSM Preprocessor

     The first step in running HSSM is to run the preprocessor PRE-HSSM to create and/or edit input data
sets.  PRE-HSSM is provided as a convenience to the user; its usage greatly facilitates the generation of
input data sets.  For convenience, blank templates for each of these screens are provided in Appendix 12.
These templates are useful for assembling data sets and may be copied for repeated usage. Appendix 10
shows the structure of the HSSM-KO and HSSM-T input data files for experienced users of HSSM who may
wish to edit directly their input data sets.
                            Table 43  Introductory PRE-HSSM Screen
             *                PRE-HSSM VERSION 1.50                  *
             *                                                         *
             *   AN INTERACTIVE PREPROCESSOR FOR  THE HSSM MODEL *
             *                                                         *
             *                     JIM WEAVER                        *
             *   UNITED STATES ENVIRONMENTAL PROTECTION  AGENCY  *
             *    R.S.  KERR  ENVIRONMENTAL  RESEARCH LABORATORY    *
             *                  ADA,  OKLAHOMA 74820                  *
             *                    DONALD COLLINGS                    *
             *        NSI TECHNOLOGY SERVICES CORPORATION        *
             *                ENVIRONMENTAL  SCIENCES                *
             *                  ADA,  OKLAHOMA 74820                  *
             *                     NOV 7, 1992                       *
  DO YOU WANT TO READ AN  EXISTING DATA  FILE ?

    ENTER 0 OR  IF  NO
    ENTER 1               IF  YES
    ENTER 2               TO  VIEW  DIRECTORY
    ENTER 3               FOR SAMPLE INPUT DATA  SET
    ENTER 4               TO  EXIT  THE PREPROCESSOR
     The main screen for the PRE-HSSM preprocessor is shown in Table 43.  The screen also displays
the file selection menu. The options available to the user are

0.  Enter 0 or  to create a new data set.

1.  Enter 1 followed by  to edit a previously created data set.  The message

ENTER THE  INPUT DATA  FILE NAME
	+	* - 4 0 - charac t er-1 imi t *	+	*
is written to the screen.  Forty characters are allowed for the data file name. A DOS path name can be
included.  If the file does not exist, the message

INPUT DATA  FILE  DOES NOT EXIST--REENTER

appears on the screen. If the file is not a valid HSSM input file, the message

                                            115            [Appendix 1 The MS-DOS Interface]

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INVALID  INPUT  DATA  FILE
Stop - Program terminated.

appears and the program must be restarted.

2. Enter 2 followed by  to view the current directory. This option executes the DOS command
DIR | MORE, so that the directory is viewed one screen at time.  After completing the command the user
is returned to the file selection menu.

3.  Enter 3 followed by   to edit a sample data set.  This data set is provided purely for the
convenience of the user and is not intended for application to specific problems,

4. Exit the preprocessor by entering 4 and pressing .


1.8.1  Saving Data to a File

     Before discussing the  individual PRE-HSSM data menus, the procedure for saving data to files and
exiting PRE-HSSM is explained. As previously noted, all data entered into PRE-HSSM must be written to
a file before exiting or restarting PRE-HSSM, otherwise all entries and/or changes will be lost.  The user
is prompted for saving data before exiting or restarting.
                                  Table 44 Writing Data Files
  WRITE THE  INPUT  VALUES TO A  FILE  ?
  ***ANY DATA ENTERED IN PRE-KOPT MUST  ***
  ***BE WRITTEN TO  A FILE BEFORE EXITING***
  *****************************************


   ENTER 0 OR   IF NO
   ENTER 1                IF YES
The screen shown in Table 44 prompts the user to decide whether or not to write the current data file to
a disk file. This screen is displayed after the user has chosen no changes in the main menu (Table 47).
To save the data to a disk file, enter 1; otherwise, press .
[Appendix 1  The MS-DOS Interface]            11 Q

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                                Table 45 Selecting File Names
  CHOOSE A FILE TO  WRITE TO:
  CURRENT INPUT FILE NAME:   sample.dat
  CURRENT OUTPUT FILE NAME:   «NONE»

   ENTER 0 OR  TO  EXIT WITHOUT WRITING  TO ANY  FILE
   ENTER 1               TO  CHANGE  THE DATA FILE  NAME
   ENTER 2               TO  OVERWRITE THE  CURRENT INPUT  FILE
When 1 is entered on Table 44, Table 45 appears, displaying the current input file name and the current
output file name, and gives the user three options.

Enter 0 or  to exit without writing any data file.

Enter 1 to change the name of the data file and write the data to that file.

Enter 2 to write the data to the current input file name.
                                Table 46 Exiting PRE-HSSM
  DO YOU WANT  TO CONTINUE  ?
   ENTER 0 OR  TO CONTINUE  WITH THE SAME  DATA SET
   ENTER 1               TO RESTART WITH A NEW DATA SET
   ENTER 2               TO EXIT THE  PREPROCESSOR
After choosing whether or not to write a disk file, the user is prompted whether to continue PRE-HSSM or
to exit (Table 46).

0. Enter 0 or  to continue with the same data set that has just been created or edited.  This
option returns control to the  PRE-HSSM Main Menu (Table 47).

1. Enter 1 and press  to restart PRE-HSSM with a new data set. This option returns control
to the Introductory PRE-HSSM Screen (Table 43).

2. Enter 2 and press  to exit PRE-HSSM. By selecting this option the user is returned to the
DOS prompt. Data previously written to files is retained on the disk; data not previously written to files is
lost.
                                            17            [Appendix 1 The MS-DOS Interface]

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1.8.2  PRE-HSSM Main Menu Commands
    Table 47 lists the names of the PRE-HSSM data entry screens.  Most of the lines in the main menu
correspond to one line in the data file used by the model.  The following options are available for use with
this menu and each of its sixteen sub-menus:

1.  Enter 0 or press  for no changes to any data item.

2.  Select a line number to view/edit the data fields associated with it by entering a line number from 1 to
16 and pressing .

3.  Enter -1 and press  to view/edit all the sub-menus in sequence. This option will direct PRE-
HSSM to go  through each  of  the sub-menus.  Once  started,  this option must  be followed through to
completion.   There is no way to escape out of the sequence without losing all data entered during the
session.
                              Table 47 PRE-HSSM Main Menu
            HSSM INPUT  DATA SCREENS

            1	SIMULATION  CONTROL  SWITCHES
            2	OUTPUT AND  PLOT FILE NAMES
            3	RUN  TITLE
            4	MATRIX PROPERTIES
            5	HYDROLOGIC  PROPERTIES
            6	HYDROCARBON (NAPL)  PHASE  PROPERTIES
            7	CAPILLARY SUCTION APPROXIMATION
            8	NAPL FLUX,  VOLUME OR CONSTANT HEAD
            9	DISSOLVED CONSTITUENT CONCENTRATION
            10	EQUILIBRIUM LINEAR  PARTITION COEFFICIENTS
            11	OILENS SUB-MODEL . 1
            12	OILENS SUB-MODEL. 2
            13	SIMULATION  PARAMETERS
            14	NUMBER OF PROFILES
            15	PROFILE TIMES
            16	TSGPLUME INPUT PARAMETERS

  CHANGE  OR VIEW INPUT DATA VALUES ?
   ENTER  0 OR   FOR NO CHANGES
   ENTER   FOR A  SINGLE LINE
   ENTER  -1              FOR ALL LINES  IN SEQUENCE
[Appendix 1  The MS-DOS Interface]

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1.8.3  Creating and Editing HSSM Data Sets

     The following pages document each data entry menu.  They are listed in the order they would appear
if the user had chosen the -1 option on the PRE-HSSM main menu (review all items in the menu). The
data items are grouped primarily by function  within the model.  As a result some parameters appear on
screens to which, at first glance, they do not belong.  This arrangement is due to the modularity of the
code.

     Each screen follows the following format:  Each data  item is numbered, and followed by its HSSM
variable name is a short description of its use and its current value.  To change a value, enter the item
number and press , then enter the new value and press  again. Each time a single
modification or a series of modifications is completed, the preprocessor displays the new data for inspection
and approval. Each data item may be modified any number of times while the screen is displayed, but only
the values displayed just before the screen is exited are saved in main memory (RAM).  After modifying
all desired data items, the complete data set may be written to a disk file. Until this time all data is stored
in RAM only, and will be lost if PRE-HSSM is exited or aborted.

     The following units are used in HSSM and are listed with their usage and abbreviation.  Care must
be taken to assure that the inputs are converted to this set of units.
Table 48 Required Units for HSSM
Quantity
Time
Depth
Dynamic viscosity
Density
Surface tension
Concentration
Soil-water partition
coefficient
Dispersivity
Various
Unit
day
meter
centipoise
grams/cubic centimeter
dyne/centimeter
milligrams/liter
liters/kilogram
meters
dimensionless
Abbreviation Used in
PRE-HSSM
D
M
CP
G/CC
DYNE/CM
MG/L
L/KG
M
*
                                             119
[Appendix 1  The MS-DOS Interface]

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                             Table 49 Simulation Control Switches
      SCREEN 1.    SIMULATION CONTROL  SWITCHES
                      1 IWR    PRINTING  SWITCH
                                O NO  OUTPUT FILES PRODUCED
                                1 ALL OUTPUT FILES PRODUCED
                      2 IKOPT  ECHO PRINT ONLY  (IF IWR = 1)
                                0 READ AND ECHO  PRINT  DATA ONLY
                                1 RUN KOPT MODEL
                      3 ICONC  DISSOLVED CONSTITUENT  SWITCH
                                0 NO CONSTITUENT PRESENT
                                1 SIMULATE DISSOLVED CONSTITUENT
                      4 ILENS  OILENS SWITCH
                                0 DO NOT  RUN OILENS MODEL
                                1 RUN OILENS MODEL
                      5 ITSGP  TSGPLUME  SWITCH
                                0 DO NOT  CREATE  TSGPLUME MODEL INPUT
                                1 CREATE  TSGPLUME MODEL INPUT FILE
        ENTER  0 OR   FOR  NO CHANGE
        ENTER   TO CHANGE  SINGLE  ITEM
        ENTER  -1              TO CHANGE  ALL ITEMS IN  SEQUENCE
                               FILE
1.  Enter the integer printing switch (0 or 1).  Entering 0 causes no output to be produced, so normally 1
will be entered for this variable.

2.  Enter the integer KOPT/echo printing switch (0 or 1).  Entering 0 will echo print the input data set
without performing a simulation (if IWR is set to 1).  Entering 1 will cause the program to read the data and
run the KOPT module of HSSM.  KOPT simulates the infiltration of the NAPL through the vadose zone.
KOPT must be run in order to run OILENS or TSGPLUME.

3.  Enter the dissolved constituent switch (0 or 1).  Entering 0 simulates NAPL phase flow without a
dissolved constituent.  Entering 1 allows the simulation of a dissolved constituent within the NAPL phase.
TSGPLUME requires a dissolved constituent.

4.  Enter the integer OILENS switch (0 or 1).  Entering 0 will prevent the OILENS model from running.
Entering 1 will allow the OILENS model to run, if the NAPL reaches the water in sufficient quantity.

5.  Enter the TSGPLUME data creation switch (0 or 1). Entering 0 will prevent HSSM-KO from creating
the TSGPLUME (HSSM-T) input data set.  Entering 1 will allow HSSM-KO to create an input data set for
TSGPLUME, if there is a dissolved constituent which reaches the water table.

     In order for HSSM-T  and the HSSM-PLT post processor to function properly, a specified set of file
types (the three-character extension to the file name following the period; i.e., name.TYP) is required to be
used by HSSM-KO.  The  PRE-HSSM interface automatically assigns the required file names whenever
a data set is saved  to the disk.
[Appendix 1  The MS-DOS Interface]
120

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                                       Table 50 Run Title
    SCREEN 3.    RUN TITLE
             1..   BENZENE TRANSPORT FROM  1500 GAL GASOLINE SPILL
             2..   1.15% BENZENE  IN GASOLINE
             3..   SANDY SOIL, PROPERTIES  FROM CARSEL  AND  PARISH
        ENTER 0  OR  FOR NO CHANGE
        ENTER  TO  CHANGE SINGLE ITEM
        ENTER -1              TO  CHANGE ALL  ITEMS IN  SEQUENCE
The  Run Title Screen (Table 50)  allows the user to enter three lines of up to 50 characters each of
information related to the data set.  A 50-character ruler bar is displayed for convenience when entering
the title. The information from this screen is reproduced as headings throughout the output files generated
by the KOPT/OILENS.

     n Any one line may be modified by entering its number at the prompt, or
     n All three lines may be modified in succession by entering -1 at the prompt.
     n The current title is accepted by pressing  or entering 0.
                                             121            [Appendix 1 The MS-DOS Interface]

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                              Table 51  Porous Medium Properties
       SCREEN 4.     MATRIX PROPERTIES
             1 WKS
                                                                 7.1000
             2 RKS
             3 KRF
                                                                    5000
                                                                       2
          SATURATED VERTICAL HYDRAULIC
          CONDUCTIVITY (M/D)
          RATIO  OF HORIZONTAL TO VERTICAL
          CONDUCTIVITY (*)
          RELATIVE PERMEABILITY  SELECTION
          INDEX
          1  = BURDINE--BROOKS/COREY
          2  = BURDINE--EQUIVALENT VAN GENUCHTEN
4 XLAMB  PORE SIZE INDEX  (*)                     2.6800
          IF KRF = 1,   LAMBDA
          IF KRF =2,   N
5 ETA    POROSITY  (*)                              0.4300
6 SWR    RESIDUAL WATER  SATURATION  (*)          0.1000
        ENTER 0  OR   FOR  NO CHANGE
        ENTER   TO CHANGE  SINGLE ITEM
        ENTER -1              TO CHANGE  ALL  ITEMS  IN SEQUENCE
1.   Enter the value of the saturated vertical water phase hydraulic conductivity, Ks, in meters per day.
Saturated hydraulic conductivity is one of the most important parameters of the model. Estimation of this
parameter is described in Appendix 3.1 "Soil Properties."  This appendix contains data from two tabulations
of soil properties.

2.  Enter the ratio of the horizontal saturated water phase conductivity to the saturated vertical water phase
hydraulic conductivity.  Anisotropy is not treated directly in HSSM, rather the model uses the product of
the ratio RKS and the  saturated vertical conductivity, Ks, to determine the hydraulic conductivity of the
aquifer.  This latter conductivity is also used for determining the effective conductivity to the NAPL for the
lens spreading. The  relationships between the conductivities are summarized in Table 52.
Table 52 Summary of Hydraulic Conductivity Relationships
Model and Region
Vadose zone (KOPT)
NAPL lens (OILENS)
Aquifer (TSGPLUME)
Hydraulic Conductivity Used
Vertical
Horizontal
Horizontal
HSSM Variables
Ks
KS*RKS
KS*RKS
3.  Select the capillary pressure model by entering 1 for Brooks and Corey or 2 for the equivalent van
Genuchten.
[Appendix 1  The MS-DOS Interface]
                                 122

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Choose the capillary pressure model to be used in HSSM calculations.  Further information on the selection
of the model parameters is given in Appendix 3.1 "Soil Properties."    Either Brooks and Corey or van
Genuchten model parameters may be used.  The appendix contains typical parameter values for each of
these models.  Although the HSSM is designed to use the Brooks and Corey model, van Genuchten model
parameters may be entered as input. The van Genuchten model parameters are converted to approximately
equivalent Brooks and Corey model parameters by a procedure developed by Lenhard et al. (1989).
For the Brooks and Corey Model:

The Brooks and Corey (1964) model equation which describes the relationship between saturation Sw and
capillary head  hc is given by
                                                     oa \
                            (20)
                                           *vw
where the residual water saturation, Swr, the air entry head ,hce, and the pore size distribution index, A,, are
fitting parameters.

Brooks & Corey's A,

The parameter A, is called the pore size distribution index, and is determined either by fitting the Brooks
and Corey model to the water/air capillary pressure curve PC(SW) by a procedure outlined by Brooks and
Corey (1964) or by non-linear curve fitting (e.g., van Genuchten et al., 1991).
For the van Genuchten Model:
NOTE: selecting the van Genuchten model causes HSSM to calculate approximately equivalent Brooks and
Corey model parameters as described in Appendix 4.
van Genuchten's model is defined by
                                Qw -
                                                     (a hcY
                                                             m
                                                                                        (21)
where
     0W  = volumetric water content
     hc = capillary head with units of m
     6wr = volumetric residual water content
     6m  = volumetric maximum water content
     a   = a parameter with units of  m"1
                                             123
[Appendix 1  The MS-DOS Interface]

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     n   = a parameter
     m  = a parameter (taken as a simple function of n)


For HSSM the reduced water content term (the left hand side of van Genuchten's model is taken to be
equal to

                                          o   _  o
                                         ^y.—r^                                    (22)
where the maximum  water saturation, 6m, is assumed to  equal the porosity.  The  parameters of van
Genuchten's model can be fitted to measured data by using a fitting program like RETC (van Genuchten
etal., 1991).

4.  Enter either the Brooks and Corey A, or van Genuchten n, depending on the capillary pressure curve
model selected.

5.  Enter the porosity, TI

6.  Enter the residual water saturation, which is determined from the measured capillary pressure curve.
[Appendix 1  The MS-DOS Interface]            124

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                                 Table 53  Hydrokxjic Properties
       SCREEN  5.   HYDROLOGIC PROPERTIES

             1 WMU      DYNAMIC VISCOSITY OF WATER  (CP)     1.0000
             2 WRHO     DENSITY OF  WATER  (G/CC)               1.0000
             3 IRT      RECHARGE INPUT TYPE                         1
                         1 = FLUX SPECIFIED
                         2 = SATURATION SPECIFIED
             4 QW/SWMAX CONSTANT WATER FLUX OR SAT.         0.0140
                         FLUX:  (M/D)
                         SATURATION:  (*)
             5 XMKRW    MAX. WATER  RELATIVE PERMEABILITY
                         DURING INFILTRATION (*)               0.5000
             6 WTABLE   DEPTH  TO WATER TABLE  (M)             10.0000
        ENTER 0  OR   FOR NO CHANGE
        ENTER   TO CHANGE  SINGLE  ITEM
        ENTER -1              TO CHANGE  ALL ITEMS IN  SEQUENCE
1 . Enter the dynamic viscosity of water, |jw, in centipoise (cp). At 20°C the viscosity of water is 1 .0 cp.

2. Enter the density of water, pw in g/cm3.  At 20°C density of pure water is 1 g/cm3.

3. Enter the type of recharge condition desired. Recharge can be specified either by specifying a recharge
rate or be specifying a vadose zone residual water saturation.

Enter 1  to select a recharge flux for the recharge input:
Enter 2 to select a vadose zone water saturation.

4. Enter the water flux, qw, in m/d or the saturation, Sw(max) (*), depending on the rainfall input type selected
in item 3.


When annual  recharge is chosen for the recharge input:

The value entered is the average annual recharge rate.  For example, with an annual recharge rate of 10
cm/yr the value entered is:
                      2.74 x1
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When water saturation is chosen for the recharge input:

If 35% of the pore space is filled by water, then 0.35 is entered here.  Using the other set of units: if the
volumetric  moisture content is 0.14 and  the porosity  is 0.40, then the equivalent saturation of  0.35 is
entered here.

Typically the moisture content  at  or above the  field  capacity would be  used here, after converting to
saturation.  The relationship between volumetric moisture content, 0W, porosity, T\, and saturation, Sw, is
given by 0W = r|Sw.  From the saturation input, HSSM-KO calculates the associated water flux.


5.  Enter the maximum water relative permeability during infiltration, kTO(max).  Since air is normally trapped
during infiltration, the effective hydraulic conductivity of the soil will be less than the saturated conductivity.
The  relationship between effective conductivity to water, Kew, and saturated conductivity to water,  Ksw is
given by
where k^ is  called the relative permeability to water.  The relative  permeability  equals zero when the
saturation is at or below residual, and equals one when the porous medium is completely saturated with
water.

To account for trapping of the air phase, the maximum effective conductivity is restricted by the value set
for kra(max).  Typical values range from 0.4 to 0.6 (Bouwer 1966); 0.5 is often used (e.g.,  Brakensiek et al.,
1981). The maximum water saturation is then determined from the kw function that  is used by HSSM.  The
remainder of the pore space is assumed to be filled with trapped air. The water saturation calculated  from
krw(max) 's tnen discarded, as only the trapped air saturation is used by the model.

5. Enter the  depth to the water table from the release point in meters. The release point is usually at the
ground surface.
[Appendix 1  The MS-DOS Interface]            126

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                         Table 54  Hydrocarbon (NAPL) Phase Properties
   SCREEN 6  NAPL PHASE PROPERTIES

             1 PMU    DYNAMIC VISCOSITY OF NAPL  (CP)    0.4500
             2 PRHO  NAPL  DENSITY  (G/CC)                0.7200
             3 SPR    RESIDUAL OIL SATURATION (*)       0.0500
             4 IAT    APPLICATION TYPE                          1
                      1 = FLUX SPECIFIED
                      2 = VOLUME/AREA SPECIFIED
                      3 = CONSTANT HEAD PONDING
                      4 = VARIABLE PONDING AFTER
                          CONSTANT HEAD PERIOD

        ENTER 0 OR  FOR NO CHANGE
        ENTER  TO CHANGE SINGLE ITEM
        ENTER -1              TO CHANGE ALL  ITEMS  IN SEQUENCE
1 .  Enter the NAPL phase viscosity, u0, in centipoise. Typical NAPL viscosities are given below in Table 55.

2.  Enter the NAPL phase density, p0, in g/cm3. For OILENS simulations, the NAPL density must be less
than that of water. Densities greater than water may be used if no OILENS simulation is performed. Some
typical NAPL densities are given below in Table 55.

Hydrocarbon densities are sometimes expressed  by  the degrees API (Perry and Chilton,  1973) scale
adopted by the American Petroleum Institute.  Degrees API is defined by
                                °API   =           - 131.5                          (25)
                                             sp.gr.

where sp.gr. is the specific of the NAPL measured at 70° F divided by the specific gravity of water
measured at 60° F.  The degrees API scale runs from 0.0 to 100.0 and covers a range of specific gravities
from 1.076 to 0.6112.
The densities and viscosities of the NAPL and water phases are used by HSSM-KO to estimate the
saturated hydraulic conductivity to the NAPL phase, Kso, by

where Ksw is the saturated hydraulic conductivity, uw and u0 are the water and oil viscosities, and pw and
p0 are the respective densities.
                                            127            [Appendix 1  The MS-DOS Interface]

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Table 55 NAPL Densities and Viscosities at 20° C
Liquid
Gasoline
Water
No. 2 Fuel Oil
Transmission Fluid
Density
g/cm3
0.75
1.00
0.87
0.89
Viscosity
cp
0.45
1.00
5.9
80
3.  Enter the residual NAPL phase saturation for the vadose zone, Sorv. By definition, the NAPL phase does
not flow at saturations less than or equal to residual.  In  this model,  the residual NAPL saturation  is
assumed to be a known constant.  Ideally, this would be obtained  by  measuring the NAPL/air capillary
pressure curve in the  presence of the amount of water filling a portion of the pore space.  Treating the
residual NAPL saturation as a constant is acknowledged to be an assumption, as in actuality the NAPL
residual saturation may vary with the hydraulic gradient and with time as the NAPL weathers (Wilson and
Conrad, 1984.) Typically the residual NAPL saturation in the vadose zone is less than that for the aquifer
(with the same media  properties).  Typical hydrocarbon  residual saturations vary from 0.10 to 0.20 in the
vadose  zone,  and from 0.15 to 0.50 in the saturated zone (Mercer and Cohen, 1990).  These values
correspond more closely to "specific retention", as the term is used in ground water hydrology, rather than
true residuals at large capillary pressure values. A different residual oil  phase saturation for the saturated
zone may be entered on the "NAPL Lens Sub-Model  Parameters. 1" menu (Table 64, item 6).

4.  Enter the NAPL phase boundary condition for the simulation.  Four options are provided for specifying
the way in which the NAPL enters the subsurface.  Not all of the release parameters are needed for each
release  option; those necessary are noted on the data screens.
     Release Options

          ©  Specified flux

               Specifies a constant flux of NAPL, corresponding to a known rate of application of NAPL
               to the ground surface for a specified time interval.  Excess NAPL is assumed to run off at
               the surface.

          ©  Specified volume/area

               Specifies a volume  per unit area of NAPL applied over a certain depth.  This results in a
               fixed volume applied  instantaneously, corresponding to a  land treatment system or a
               landfill.
[Appendix 1  The MS-DOS Interface]
128

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          ®  Constant head ponding

               Specifies constant head ponding for a specified duration.  The ponding depth abruptly goes
               to zero at the end of the release. This condition is used to simulate a hydrocarbon tank
               rupture which is contained within a berm, for example.

          ©  Variable ponding after a period of constant head ponding

               Specifies constant head ponding for a  specified duration, followed by a gradual decrease
               to zero head as the NAPL infiltrates.

The values of the necessary parameters are then entered in Table 58, Table 59, Table 60, or Table 61.
                                              129            [Appendix 1 The MS-DOS Interface]

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                      Table 56 Capillary Suction Approximation Parameters
   SCREEN 7.   CAPILLARY  SUCTION APPROXIMATION PARAMETERS

             1  HWE     AIR  ENTRY  HEAD  (M)                     4.5000
             2  WSIG    WATER SURFACE TENSION  (DYNE/CM)    65.0000
             3  OSIG    NAPL SURFACE TENSION  (DYNE/CM)      35.0000
        ENTER 0 OR   FOR NO CHANGE
        ENTER  TO  CHANGE  SINGLE ITEM
        ENTER -1              TO  CHANGE  ALL  ITEMS IN SEQUENCE
1. If the Brooks and Corey model has been selected, enter the absolute value of the air entry head, hce,
in meters.  This value is determined as a parameter from the water/air capillary pressure curve (see matrix
properties, Table 51).  If the van Genuchten model has been selected, enter a in meters"1.

2.  Enter the water/air surface tension, aaw, in dyne/cm. At 20°C the surface tension of pure water is 72.8
dyne/cm. A lower value, say 65 dyne/cm, may be appropriate for soils and/or contaminated sites.

3.  Enter the NAPL/air  surface tension, aoa, in dyne/cm.  Table 57 shows typical surface tension values
for several petroleum products.
Table 57 Surface Tensions of Several
Fuels (Wu and Hottel, 1991)
Liquid
gasoline
kerosene
gas oil
lubricating fractions
fuel oils
Surface tension
(dyne/cm)
26
25-30
25-30
34
29-32
[Appendix 1  The MS-DOS Interface]
130

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                      Table 58 Hydrocarbon (NAPL) Flux Boundary Condition
      SCREEN  8A.  NAPL FLUX BOUNDARY CONDITION

            1  QP    NAPL FLUX  (M/D)        .                0.4522
            2  TPB   NAPL EVENT BEGINNING TIME  (D)        0.0000
            3  TPE   NAPL EVENT ENDING TIME  (D)           1.0000

        ENTER  0 OR   FOR  NO CHANGE
        ENTER   TO CHANGE  SINGLE  ITEM
        ENTER  -1              TO CHANGE  ALL ITEMS IN  SEQUENCE
1. Enter the constant NAPL flux, q0, in meters per day. NAPL phase fluxes in excess of the maximum
effective NAPL phase conductivity are assumed to run off.

2. Enter the beginning time of the NAPL release in days, usually this is zero.

3. Enter the ending time of the NAPL release in days.
             Table 59 Hydrocarbon (NAPL) Volume Per Unit Area Boundary Condition
    SCREEN 8B.   NAPL VOLUME/AREA BOUNDARY CONDITION

            1  PVOL NAPL VOLUME/AREA  (M)                 0.4000
            2  DPL  LOWER DEPTH OF NAPL  ZONE    (M)      0.5000

        ENTER  0  OR  FOR NO CHANGE
        ENTER   TO CHANGE SINGLE  ITEM
        ENTER  -1              TO CHANGE ALL ITEMS  IN SEQUENCE
1. Enter the volume of the NAPL phase per unit surface area that is either placed in a land treatment facility
or a landfill (cubic meters/square meter).

2. Enter the depth of the bottom of the contaminated zone, dpl (meters).
                                            131            [Appendix 1  The MS-DOS Interface]

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             Table 60 Hydrocarbon (NAPL) Constant Head Ponding Boundary Condition
   SCREEN 8C.  CONSTANT  NAPL HEAD  BOUNDARY  CONDITION

            1 TPB   NAPL EVENT BEGINNING TIME (D)        0.0000
            2 TPE   NAPL EVENT ENDING  TIME  (D)           1.0000
            3 HS    CONSTANT HEAD FOR  IAT = 3  (M)        0.2000

       ENTER 0 OR  FOR NO  CHANGE
       ENTER  TO CHANGE SINGLE ITEM
       ENTER -1              TO CHANGE ALL ITEMS IN SEQUENCE
1.  Enter the beginning time of the NAPL release in days, usually this is zero.

2.  Enter the ending time of the NAPL release in days.

3.  Enter the depth of constant head ponding, Hs, in meters.
             Table 61 Hydrocarbon (NAPL) Variable Head Ponding Boundary Condition
      SCREEN 8D.  VARIABLE HEAD PONDING BOUNDARY CONDITION

            1 TPB   NAPL EVENT BEGINNING TIME  (D)       0.0000
            2 TPE   END OF  CONSTANT HEAD PERIOD (D)    1.0000
            3 HS    CONSTANT  HEAD FOR TPB TO TPE  (M)   0.2000

       ENTER 0 OR   FOR NO CHANGE
       ENTER   TO CHANGE SINGLE  ITEM
       ENTER -1              TO CHANGE ALL ITEMS IN SEQUENCE
1.  Enter the beginning time of the NAPL release in days, usually this is zero.

2.  Enter the ending time of the NAPL release in days.

3.  Enter the depth of constant head ponding, Hs, in meters.
[Appendix 1  The MS-DOS Interface]           132

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                         Table 62 Dissolved Constituent Concentration
      SCREEN 9.   DISSOLVED CONSTITUENT CONCENTRATION


            1 COINI    INITIAL CONCENTRATION IN NAPL  (MG/L) 8208.0000

        ENTER 0 OR   FOR NO  CHANGE
        ENTER   TO CHANGE SINGLE ITEM
        ENTER -1              TO CHANGE ALL ITEMS  IN SEQUENCE
1.  Enter the initial concentration of the chemical constituent in the NAPL phase, c0(ini)1 in mg/L.  HSSM
idealizes the multiphase/multicomponent system as consisting of an "NAPL" phase that contains some
small fraction of a dissolved constituent. The dissolved constituent can partition between the fluids and the
solid.  The concentration in the NAPL of the chemical is entered here.  For example benzene composes
1.14% by mass of the idealized gasoline mixture used by Baehr & Corapcioglu (1987).  The initial benzene
(the dissolved constituent) concentration in gasoline (the NAPL or "oil") is given by


                                      Cb   -   fdpg                                 (27)

where Cb is the concentration of benzene in the gasoline, fb, is the mass fraction of benzene in gasoline,
pg is the density of the gasoline. Therefore
                 Ch(glcm3)  =          (0.730/cm3)  -   0.0083flr/cm3            (28)
Converting the gasoline concentration to the required units gives
         C.dnglL)  -   Cb(9lcm^                               ,   830Om0/L    (29)
                                      v     L     }    \     g    )
                                           133            [Appendix 1  The MS-DOS Interface]

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                          Table 63 Equilibrium Linear Partition Coefficients
     SCREEN  10.   EQUILIBRIUM LINEAR  PARTITION  COEFFICIENTS


             1 XXKO   NAPL/WATER (*)                         311.0000
             2 XXKS   SOLID/WATER   (L/KG)                     0.8300
             3 XXKSH  SOLID/WATER  (HYDROCARBON)   (L/KG)     0.8300
             4 RHOS   BULK  DENSITY  (GR/CC)                    1.5100
        ENTER  0  OR  FOR NO  CHANGE
        ENTER   TO CHANGE  SINGLE  ITEM
        ENTER  -1              TO CHANGE  ALL ITEMS  IN SEQUENCE
1. Enter the linear equilibrium partitioning coefficient between the NAPL and the water phase concentrations
of the chemical constituent. By definition

                                       Co   =   K0cw                                 (30)

where  K0 is the dimensionless partition coefficient between the  NAPL phase (c0) and water phase (cw)
concentrations of the chemical constituent. The partitioning between the NAPL phase and the water phase
depends on the composition of the NAPL. Estimation of K0 is discussed in Appendix 3.2 "NAPL/Water
Partition Coefficient."  A  utility program for performing the necessary calculations, called  RAOULT,  is
described in Appendix 6.

2. Enter the linear equilibrium partitioning coefficient, Kd,  in liters per kilogram between the soil and the
water phase concentrations (cs and cw) of the constituent.  By definition


                                       cs   =   Kdcw                                 (31)
where  Kd is  the  partition coefficient in  liters per kilogram between  the solid  (cs )  and water phase
concentrations (cw).  Kd is commonly estimated from the fraction organic carbon of the media, foc, and the
organic carbon partition coefficient, Koc as
Table 98 in Appendix 3 lists Koc values for several hydrocarbon constituents.

3.  Enter the linear equilibrium partitioning coefficient between the soil and the water phase concentrations
(cs and cj of the hydrocarbon phase.  Like the  solubility of the  NAPL phase, discussed below, this
parameter is not critical.  This coefficient is used for estimating the  partitioning of the dissolved fractions
of the NAPL (i.e., all of the NAPL chemicals except the chemical constituent of interest).

4.  Enter the bulk density, pb, of the soil in g/cm3.  Porosity, r|, and bulk density, pb are related by
[Appendix 1  The MS-DOS Interface]            -j 34

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                                     PA  =  P.(1  - TI)                                (33)

where ps is the solids density.  The density of quartz is approximately 2.65 g/cm3. The values for porosity
and bulk density must be related by equation (33).
                                             135            [Appendix 1 The MS-DOS Interface]

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                        Table 64  OILENS Model Parameters, First Screen
       SCREEN  11.  OILENS  SUB-MODEL PARAMETERS.1

            1  RADI    RADIUS OF SOURCE   (M)                      2.0000
            2  RMF     RADIUS MULTIPLICATION FACTOR  (*)          1.0010
            3  FRING   CAPILLARY THICKNESS PARAMETER  (M)         0.0100
            4  VDISP   AQUIFER VERTICAL DISPERSIVITY  (M)         0.1000
            5  GRAD    GROUNDWATER  GRADIENT    (*)                 0.0100
            6  SPRB    AQUIFER RESIDUAL NAPL SATURATION (*)     0.1500

        ENTER  0 OR  FOR NO CHANGE
        ENTER   TO CHANGE SINGLE  ITEM
        ENTER  -1              TO CHANGE ALL ITEMS IN  SEQUENCE
1. Enter the radius of the contaminant source, Rs, in meters. When no OILENS simulation is desired (Run
OILENS is not selected on the Simulation Control Switches screen), a per unit area simulation can be
performed by entering 0.5642 as the radius of the source. The resulting source area is  1.0 m2.

2.   Enter the value  of the radius multiplication factor.  A value of 1.001 is suggested for the radius
multiplication factor (RMF). The RMF is used to multiply the source radius for starting the OILENS model.
This is necessary since the OILENS equations are singular at the source radius. Starting the simulation
at a small distance from the true radius avoids this singularity.  This  procedure does, however, introduce
a mass balance error into the solution, so the minimum value of RMF which permits the simulation to
proceed should be used.  At no time should the RMF exceed 1.1. When the singularity is encountered,
the  OILENS model will display the error message

OILENS SINGULARITY ENCOUNTERED,   INCREASE RMF

The RMF should then be increased  and the simulation retried.

3.  Enter the value of the capillary thickness parameter (meters).  The capillary thickness parameter gives
the  model a thickness which must build up in the capillary fringe before spreading of the NAPL occurs.
Typically, a value of 0.01m should be entered for this parameter.  This results in a small thickness of NAPL
that is built up before spreading begins.

The capillary thickness parameter can also be used to incorporate the effect of water table fluctuation on
the  lens radius. Water table fluctuation can cause trapping of NAPL throughout a  smear zone,  and the
trapped NAPL is not available for radial spreading. To include this effect, the capillary thickness parameter
should be calculated by
          ( capillary'
            thickness
smear zone thickness x residual NAPL saturation     (34)
          {parameter)               maximum NAPL saturation in lens


The smear zone thickness should be taken as the maximum water table fluctuation. The residual NAPL
saturation and maximum NAPL saturation in the lens are described under Screens 6, 11 and 12.
[Appendix 1  The MS-DOS Interface]            136

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4.  Enter the vertical dispersivity of the aquifer, Av, in meters.  See the discussion of longitudinal dispersivity
under Table 70 below.

5.  Enter the groundwater gradient.  Typical maximum natural gradients are 0.005 to 0.02. Since pumping
wells are not allowed in TSGPLUME, natural gradients should  be used here.

6.  Enter the residual NAPL phase saturation in the aquifer, Sors. See notes above for vadose zone residual
NAPL saturation.
                                             137            [Appendix 1  The MS-DOS Interface]

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Table 65 OILENS Model Parameters, Second Screen
SCREEN 12. OILENS SUB-MODEL PARAMETERS . 2
1 XMSOL
2 SOLC
3 SOLH
ENTER 0 OR
ENTER  FOR NO CHANGE
NUMBER> TO CHANGE SINGLE ITEM
TO CHANGE ALL ITEMS IN
(*) 0
(MG/L) 1750
(MG/L) 10
SEQUENCE
3260
0000
0000

1.   Enter the saturation of the LNAPL, S0(max), in the NAPL lens.  In HSSM, the lens is idealized as a
uniformity saturated lens, although in actuality the NAPL saturation varies within the lens. The thickness
of the lens in HSSM represents the ratio of the volume of the lens to its area.  Within the lens the NAPL
has a certain saturation. Estimation of the NAPL lens saturation is discussed in Appendix 3.3, and a utility
called NTHICK for performing the necessary calculation is described in Appendix 7.

2.   Enter the chemical constituent water solubility, sk, in mg/L.  The solubility entered  here is the "pure
component"  solubility which is tabulated in several sources (i.e., Mercer et al., 1990; Sims et al.,  1991;
USEPA, 1990). Several values are given in Table 98.  The solubility is used by HSSM to limit the water
phase concentration. Appropriately chosen K0 values (which imply maximum water phase concentrations
much less than the pure phase solubilities) make this parameter  redundant for NAPLs composed  of
mixtures of chemicals.

3.   Enter the NAPL water solubility in mg/L.  This coefficient represents the solubility of all of the NAPL
constituents, except the chemical constituent that is simulated. The  solubility of the chemical constituent
is entered separately.  Further, this value is only used by  the model in a substantial way if one of the
ending criteria is used. Therefore the value of the NAPL solubility is not a critical parameter.

The value of NAPL solubility  must  be  greater than zero if the OILENS Simulation ending criterion (see
below) is set to © "NAPL lens spreading stops." Bauman  (1989) estimated that the typical solubility of
gasoline is on the order of 50 to 200 mg/L.
[Appendix 1  The MS-DOS Interface]
138

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                             Table 66  Simulation Control Parameters
        SCREEN 13.   SIMULATION PARAMETERS

             1  TM      SIMULATION  ENDING TIME   (D)             2500.0000
             2  DM      MAXIMUM SOLUTION  TIME  STEP   (D)          20.0000
             3  DTPR    MINIMUM TIME BETWEEN PRINTED TIME STEPS
                        AND MASS BALANCE  CHECKS  (D)                 0.1000
             4  KSTOP  ENDING  CRITERION                                    4
                1 = USER  SPECIFIED TIME
                2 = LENS  SPREADING STOPS
                3 = MAXIMUM CONTAMINANT  MASS  FLUX TO AQUIFER
                4 = CONTAMINANT MASS FLUX IN  OILENS <  OPERC * MAX
             5  OPERC  MINIMUM CONTAMINANT MASS IN LENS  (*)      0.0100
        ENTER  0 OR    FOR NO CHANGE
        ENTER    TO CHANGE  SINGLE ITEM
        ENTER  -1               TO CHANGE  ALL  ITEMS  IN SEQUENCE
1.  Enter the simulation ending time in days.  This time must always be specified, even though  other
stopping options are available and may override the maximum simulation time.

2. Enter the maximum solution time step in days. This should be set as high as possible, although internal
error correction routines will often limit the actual size of the step taken.  Values of up to 25 days are
usually acceptable.  Overly large step sizes may introduce mass balance errors in the model  results.

3. Enter the minimum time between printed time steps in days.  Although the model uses a variable time
step ordinary differential equation solver,  at times during the simulation HSSM takes very small steps.
Results from these steps  are  of little  use and dramatically increase the size of the output files.  This
parameter prevents the output of every  solution step and should be set to 0.1 or 0.25 days. This parameter
does not affect the simulation itself, but only the information that is output.

For most chemicals leaching out of the lens, after the peak mass flux into the aquifer has  passed,  there
is a relatively long period of time where the mass flux into the aquifer slowly declines.  During this time
period, the  user set minimum time between printed time steps may be overridden in order to reduce the
size of the output and plot files.  An additional criteria is added that the mass flux must change by at least
1.0 percent for the results to be output. This feature cannot be overridden by the user.

4.  The  OILENS Simulation ending criterion  determines how  the HSSM-KO simulation  terminates.
Because it is not possible to predict when certain events in the simulation will occur, several of the options
cause the simulation to end only after the event of interest has occurred.  In these cases the  user specified
ending time  is overridden and the simulation continues.

NOTE: The fourth option,  "Contaminant leached from lens" must be chosen in order to use the
    HSSM-T model.
                                              139            [Appendix 1  The MS-DOS Interface]

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© User-specified ending time

Stop at the simulation ending time specified above.

® NAPL lens spreading stops

Stop the simulation when the NAPL lens stops spreading.  If no NAPL lens forms before the specified
ending time, then the simulation stops at the specified ending time.  If a lens does form, the ending time
is overridden and the simulation continues until the NAPL lens stops spreading. When the NAPL phase
solubility is near zero, it is possible that, in the model, the lens motion may never stop, since kinematic
theory predicts that an infinite amount of time is required for all of the NAPL to pass a given depth. The
NAPL trickles into the lens throughout the simulation, and NAPL lens motion stops when the flux into the
lens drops below the NAPL dissolution flux into the aquifer.  If the NAPL solubility is zero and no chemical
constituent is simulated, no NAPL is dissolved and the motion may continue indefinitely.  To avoid this
problem, a non-zero NAPL solubility (see Hydrocarbon Phase Parameters) is required for this situation.

3) Maximum contaminant mass flux into aquifer

Stop the simulation when the maximum chemical constituent flux into the aquifer occurs.  If no NAPL lens
forms before the specified ending time, the simulation stops at the specified ending time.  If a lens forms,
the ending time is overridden and the simulation continues until the maximum mass flux occurs.

® Contaminant leached from lens drops below a given fraction of the total mass in the lens

Stop the simulation when the contaminant mass in the NAPL lens drops below a specified fraction of the
maximum contaminant mass that has been contained within the lens during the entire simulation. The
fraction is specified by the user.  If no NAPL lens forms before the user-specified ending time (above), the
simulation stops at the specified ending time.
5. Enter the mass factor stopping criterion for the ending criterion ® "Contaminant leached from lens". Two
percent (0.02) or less should be used for this factor.
[Appendix 1 The MS-DOS Interface]             140

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                                Table 67  Number of Profiles
    SCREEN 14.   PROFILES

          1 NTIMES  NUMBER OF  PROFILES  DESIRED (UP TO  10)

        ENTER  0  OR  FOR NO CHANGE
        ENTER   TO CHANGE SINGLE  ITEM
        ENTER  -1             TO CHANGE ALL ITEMS IN SEQUENCE
                                                    10
    1. Enter the number of KOPT saturation vs depth profiles (Saturation Profiles graph) and OILENS lens
thickness vs. radius profiles (NAPL Lens Profiles graph).  Both are produced at specified times (screen
15) along with mass balance approximations.  Up to ten profiles are allowed.
                                   Table 68  Profile Times
       SCREEN  15.   PROFILE TIMES
            PR  (  1) =
            PR  (  2) =
            PR  (  3) =
            PR  (  4) =
            PR  (  5) =
            PR  (  6) =
            PR  (  7) =
            PR  (  8) =
            PR  (  9) =
            PR  (10)
       1.0000
       2.0000
=      4.0000
       5.0000
       7.5000
       9.0000
     720.0000
=  1000.0000
=  1500.0000
=  2000.0000
        ENTER 0  OR  FOR NO CHANGE
        ENTER  TO  CHANGE  SINGLE ITEM
        ENTER -1              TO  CHANGE  ALL ITEMS  IN SEQUENCE
    A maximum of ten profile times (days) may be entered depending on the value of NTIMES entered
in screen 14.
                                           141
                                    [Appendix 1 The MS-DOS Interface]

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                            Table 69 TSGPLUME Input Data Menu
          SCREEN 16.  TSGPLUME DATA  INPUT SCREENS

                   1	TSGPLUME INPUT DATA
                   2	SIMULATION  TIME
                   3	WELL  LOCATIONS

       ENTER 0  OR  FOR NO CHANGE
       ENTER  TO CHANGE SINGLE ITEM
       ENTER -1             TO CHANGE ALL ITEMS IN  SEQUENCE
    From screen 16, three screens of TSGPLUME input data are assessed. None of these data are used
in KOPT/OILENS for simulation, but are processed and printed in the TSGPLUME input data file. After the
KOPT/OILENS simulation is completed the mass flux profile to the aquifer is added to the data file.
                                 Table 70  TSGPLUME Data
        SCREEN  16A.  TSGPLUME  DATA

            1 DLONG    AQUIFER  LONGITUDINAL  DISPERSIVITY  (M)       10.0
            2 DTRAN    AQUIFER  TRANSVERSE DISPERSIVITY  (m)          1.0
            3 PMAX     PERCENT  MAX. CONTAM.  RADIUS  (*)            101.0
            4 CMINW    MINIMUM  OUTPUT  CONCENTRATION (MG/L)        0.001
            5 ZLAM     AQUIFER  DECAY RATE COEFFICIENT (1/D)         0.0
            6 NWELL    NUMBER OF RECEPTOR WELLS  (*}                    2

        ENTER 0  OR  FOR NO CHANGE
        ENTER  TO CHANGE SINGLE ITEM
        ENTER -1             TO CHANGE ALL ITEMS IN SEQUENCE
1.  Enter the longitudinal dispersivity of the aquifer, AL, in meters.

2.  Enter the horizontal transverse dispersivity of the aquifer, AT, in meters.
[Appendix 1  The MS-DOS Interface]           142

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The dispersivities are defined by
                                          DL   =  ALv
                                          DT   =  ATv                                   (35)
                                         Dv   =  Avv
where DL, DT, and  Dv are the longitudinal, horizontal  transverse, and vertical transverse  dispersion
coefficients; AL,  AT, and  Av are likewise  the longitudinal, horizontal transverse,  and vertical transverse
dispersivities; and v is the seepage velocity in the mean flow direction.

Dispersive mixing in  aquifers results from solute transport through heterogeneous porous media.  As the
contaminant plume spreads it  "experiences"  more heterogeneity and the apparent dispersion coefficient
increases. Thus the dispersion coefficients,  DL, DT and Dv are not fundamental  parameters, but exhibit
scale dependence.

Gelhar et al. (1992) recently reviewed dispersivities determined at 59 sites and considered the reliability
of the dispersion coefficients.  They concluded that there are  no highly reliable longitudinal dispersion
coefficients at scales greater than 300m.  Notably, at a given scale, dispersivities have been found to vary
by 2 to 3 orders of magnitude, although the  lower  values are more reliable.  Based on these data,
horizontal transverse dispersivities are typically from 1/3 to almost 3 orders-of-magnitude  lower than
longitudinal dispersivities.  Vertical transverse dispersivities are typically (although  based on a very limited
data set)  1-2 orders-of-magnitude lower than horizontal transverse dispersivities.  The very low values of
vertical transverse dispersivities reflect roughly horizontal stratification of sedimentary materials.

3. Enter the percentage  of the maximum contaminant radius which is  to be used in  the TSGPLUME
simulation, which requires a constant radius for the input mass flux.

Since the radius of the NAPL  lens changes continuously during part of the simulation,  it  may not be
possible to preselect an appropriate lens  radius for the TSGPLUME module.   It is desirable, however, to
match the radius of the lens to the peak mass flux into the aquifer.  Thus TSGPLUME simulation can use
the radius which occurs at the  time of the maximum mass flux. With this approach the peak mass flux is
not overly diluted due to a large lens radius. (Nor is it "condensed" due to an overly small  radius). The lens
radius which occurs at the time of the maximum mass flux is automatically selected if 101 is entered for
the percent maximum contaminant radius. Thus, the recommended value of this parameter is 101.  It may
be  desirable for users to  determine  the effect of varying  the size  of  the source on  the  aquifer
concentrations.

4. Enter the minimum concentration (mg/L) for TSGPLUME to include in the output. Concentrations below
this value will be reported as zero.  A nonzero value of this parameter is required for proper execution of
the TSGPLUME module.   Typically, a concentration  of   0.001  mg/L  is  suitable for the minimum
concentration.

5. Enter the half-life  of the constituent in the aquifer.  This value is used only by the TSGPLUME model.

6. Enter the number of wells (a maximum of six) for  which TSGPLUME is to calculate  concentration vs
time for the Well Concentrations graph.
                                              143             [Appendix 1 The MS-DOS Interface]

-------
                             Table 71 TSGPLUME Simulation Time
        SCREEN 16B.   TSGPLUME SIMULATION TIMES

              1 BEGT     BEGINNING TIME  (D)                        100.0
              2 ENDT     ENDING TIME  (D)                          5000.0
              3 TINC     TIME INCREMENT  (D)                         50.0
              4 TAQU     AQUIFER THICKNESS (M)                      15.0

        ENTER 0 OR  FOR  NO CHANGE
        ENTER  TO CHANGE  SINGLE  ITEM
        ENTER -1              TO CHANGE  ALL ITEMS IN  SEQUENCE
1. Enter the beginning time in days for the TSGPLUME simulation. See note below.

2. Enter the ending time in days for the TSGPLUME simulation. See note below.

3. Enter the time  increment in  days for TSGPLUME output between the beginning  and ending times
specified above. Typically 50 or 100 days is adequate for the time increment. See note below.

NOTE: Before running the model, it is not possible to guess precisely when the contaminant arrives at or
    passes a given receptor point.  HSSM-T will override the user supplied beginning and ending times
    which allows the model  to produce smooth concentration histories at the receptor point.  Particular
    effort is expended in HSSM-T to calculate when the contaminant first arrives at the receptor point and
    when the peak concentration arrives. The duration of mass flux into the aquifer is used to determine
    a proposed time increment for HSSM-T output.  If one hundredth of the mass flux input duration is
    greater than the user specified time increment the user is prompted to increase the time increment:

    ***  TSGPLUME RECOMMENDS CHANGING  THE TIME INCREMENT
    ***  FROM  0.5000  DAYS TO 98.60 DAYS
    ***  ACCEPT THE  CHANGE ?  (Y OR N)

    HSSM-T is making the user an offer that shouldn't be refused, at least for  an initial simulation. If the
    resulting concentration history curve is not  smooth enough, the user may reduce the  time increment
    for HSSM-T to produce a finer spacing in time.

    If the user does not accept the change, he/she is prompted to decide between the original time
    increment or to enter a new time increment.

4.  Enter the thickness of the aquifer in meters.
[Appendix 1 The MS-DOS Interface]           144

-------
                              Table 72 TSGPLUME Well Locations
      SCREEN  16C.   WELL  LOCATIONS

          #         X            Y

          1         25.         00.
          2         50.         00.

        ENTER 0 OR   FOR NO  CHANGE
        ENTER   TO CHANGE SINGLE ITEM
        ENTER -1               TO CHANGE ALL  ITEMS  IN SEQUENCE
Enter up to six well locations, as X and Y coordinates in meters. X is directed along the longitudinal axis
of the plume (the direction of groundwater flow) and Y is directed transversely distance to the X axis. The
origin of the coordinate system is located at the center of the source (see Figure 9). The number of entries
will be truncated depending on the value of Number of receptor wells on Table 70.
                                            145            [Appendix 1  The MS-DOS Interface]

-------
1.9  Running the KOPT, OILENS and TSGPLUME Modules


    This section describes the operation of the HSSM-KO and HSSM-T modules.  These programs are
the heart of the simulation model. The DOS interface program (HSSM-DOS) can run the modules by
shelling out to DOS and issuing the commands listed below. The HSSM-DOS commands are listed in
Table 40.  The user may also execute the commands directly from the DOS prompt.

    Once an input data file has been created, the HSSM-KO module is executed by the DOS command

HSSM-KO  NAME.DAT

where NAME . DAT is the input data file. The command assumes the default directory contains the HSSM-
KO.EXE file, or that the HSSM directory has been added to the path (see Appendix 1.7). Table 73 shows
the first screen that appears when HSSM-KO is executed.  This screen identifies the model  and the
authors.   Pressing return displays the disclaimer  screen (Table 74).  Carefully note the disclaimer
messages. Sound scientific and engineering judgement is required when applying models and the user
is responsible for the application of the model.
                           Table 73 Introductory HSSM-KO Screen
               ***************************************************
                                                                    *
                                   HSSM                            *
                                                                    *

                      HYDROCARBON SPILL SCREENING MODEL          *
                                                                    *

               INCLUDING THE KOPT, OILENS AND  TSGPLUME  MODELS  *
                                                                    *

                              JAMES W.  WEAVER                      *
               UNITED STATES ENVIRONMENTAL PROTECTION AGENCY   *
                R.S.  KERR ENVIRONMENTAL RESEARCH LABORATORY    *
                           ADA,  OKLAHOMA 74820                    *
                                                                    *

               INCLUDING OILENS--HYDROCARBON MOVEMENT ON THE   *
                                WATER TABLE                        *
               RANDALL CHARBENEAU, SUSAN SHULTZ,  MIKE JOHNSON  *
                ENVIRONMENTAL AND WATER RESOURCES ENGINEERING  *
                     THE UNIVERSITY OF TEXAS AT AUSTIN           *
                                                                    *

                                VERSION 1.00                       *
[Appendix 1  The MS-DOS Interface]           145

-------


*
*
*
*
*
*
*
*
*
•A-
*
*

Table 74 Disclaimer Screen

WARNING :
THIS PROGRAM SIMULATES IDEALIZED BEHAVIOR OF
OILY- PHASE CONTAMINANTS IN IDEALIZED POROUS
MEDIA, AND IS NOT INTENDED FOR APPLICATION TO
HETEROGENEOUS SITES.
THE MODEL RESULTS HAVE NOT BEEN VERIFIED BY
EITHER LAB OR FIELD STUDIES .
READ USER GUIDE FOR FURTHER INFORMATION BEFORE
ATTEMPTING TO USE THIS PROGRAM.
NEITHER THE AUTHORS, THE UNIVERSITY OF TEXAS,
NOR THE UNITED STATES GOVERNMENT ACCEPTS ANY
LIABILITY RESULTING FROM THE USAGE OF THE CODE
THE U.S. E.P.A DOES NOT OFFICIALLY ENDORSE THE
USE OF THIS CODE.



*
*
*
*
*
*
*
*
*

A list of the file names used by HSSM-KO and HSSM-T is displayed in Table 75.
                         Table 75 Output File Names and Run Options
  OUTPUT AND PLOT  FILE NAMES:

  HSSM-KO INPUT DATA FILE    BENZENE.DAT
  HSSM-KO OUTPUT               BENZENE.HSS
  HSSM-KO PLOT 1               BENZENE.PL1
  HSSM-KO PLOT 2               BENZENE.PL2
  HSSM-KO PLOT 3               BENZENE.PL3
  HSSM-T INPUT DATA FILE      BENZENE.PMI
  HSSM-T OUTPUT                BENZENE.TSG
  HSSM-T PLOT                  BENZENE.PMP

  TO RUN HSSM-KO            ENTER 
  TO CHANGE  INPUT  FILE     ENTER F
  TO VIEW DIRECTORY        ENTER D
  TO EXIT                    ENTER 1
The names must follow a strict naming convention for the TSGPLUME module (HSSM-T) and the HSSM-
PLT post-processor to function properly.  For the user's convenience the correct file names are generated
automatically by PRE-HSSM. These should not be modified by the user.

    As indicated in Table 75, the user may either run HSSM-KO, change the input data file, view the
current directory or exit the program. Upon beginning a simulation the model writes messages to the
screen as the computations proceed. These allow the simulation to be tracked by  the user.  Table 76
contains a typical set of screen messages for a simulation.
                                            147            [Appendix 1 The MS-DOS Interface]

-------
                        Table 76 Typical HSSM-KO Screen Messages
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * **
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            ** *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            * * *
            ** *
            * * *
            * * *
 15.00  DAYS
 30.00  DAYS
 90.00  DAYS
130.00  DAYS
175.00  DAYS
DATA  INPUT
DATA  INITIALIZATION
SIMULATION BEGINNING
OIL INFILTRATION
OIL REDISTRIBUTION
CHEMICAL REACHES WATER TABLE
OIL LENS FORMS
PROFILING AT
PROFILING AT
PROFILING AT
PROFILING AT
PROFILING AT
SIMULATION END
POST  PROCESSING
CREATING OUTPUT FILE:
BENZENE.HSS
PROCESSING PLOT FILE CONTENTS
REPACKING FILE 18
REPACKING FILE 19
CREATING KOPT/OILENS PLOT FILE:
BENZENE.PL1
CREATING KOPT/OILENS PLOT FILE:
BENZENE.PL2
CREATING KOPT/OILENS PLOT FILE:
BENZENE.PL3
CREATING TSGPLUME  DATA FILE:
BENZENE.PMI
HSSM  END
    The HSSM-T implementation of TSGPLUME is designed to be used with HSSM-KO.  If the data set
for HSSM-KO has switches set appropriately, and if the dissolved chemical of interest reaches the water
table (either through the formation of a NAPL lens or by the leaching from an immobilized NAPL body in
the vadose zone), then an input data set for TSGPLUME is created by running HSSM-KO. The necessary
flags and conditions for TSGPLUME data file generation are summarized in Table 77.   These parameters
are described in detail in Appendix 1.8.2.
[Appendix 1 The MS-DOS Interface]
       148

-------
Table 77 HSSM-KO Data Switches for the Creation of TSGPLUME
(HSSM-T) input Data Files
Condition or
switch
IWR = 1
IKOPT = 1
ILENS = 1
ICONC = 1
ITSGP = 1
KSTOP = 4
"large"
simulation
ending time
(TM)
PRE-HSSM Screen
Screen 1 (Table 49)
Screen 1 (Table 49)
Screen 1 (Table 49)
Screen 1 (Table 49)
Screen 1 (Table 49)
Screen 1 3 (Table 66)
Screen 1 3 (Table 66)
Effect
Output and plot files produced
KOPT module is run
OILENS module is run
Chemical constituent is included in the simulation.
Attempt to create the TSGPLUME (HSSM-T. EXE) input
data.
End HSSM-KO.EXE simulation when a small fraction
chemical constituent remains in the oil lens.
of
Allow sufficient simulation time for chemical to reach the
water table before ending simulation (with KSTOP = 4
simulation ending time is over-ridden if the chemical
reaches the water table.)
Once HSSM-KO has run and produced an HSSM-T input data file, HSSM-T can be executed by entering
the command:

HSSM-T NAME.PMI

where NAME.PMI is the input data file.  When HSSM-T executes, screen messages appear as shown in
Table 78.  After pressing return, the file names for the simulation appear as indicated in Table 79.
                                           149
[Appendix 1 The MS-DOS Interface]

-------
Table 78 Introductory HSSM-T Screen

*
* TSGPLUME
*
* TRANSIENT SOURCE GAUSSIAN PLUME MODEL
*
*
* MIKE JOHNSON
* RANDALL CHARBENEAU
* THE UNIVERSITY OF TEXAS AT AUSTIN
*
* JIM WEAVER
* ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATO
* UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
*
* VERSION 1.00


Table 79 HSSM-T Output File Names and Run
OUTPUT AND PLOT FILE NAMES:
HSSM-KO INPUT DATA FILE BENZENE.DAT
HSSM-KO OUTPUT BENZENE. HSS
HSSM-T INPUT BENZENE. PMI
HSSM-T OUTPUT BENZENE . TSG
HSSM-T PLOT BENZENE. PMP
TO RUN TSGPLUME ENTER 
TO CHANGE INPUT FILE ENTER F
TO VIEW DIRECTORY ENTER D
TO EXIT ENTER 1


*
*
*
*
Tt
*
*
*
*
*
*
RY*
*
*
*


Options

When HSSM-T executes, a set of messages is written to the screen (Table 80).  These messages inform
the user on the progress of the simulation. The example shown has only one receptor location; when  more
receptors are used, more messages like these are produced.
[Appendix 1  The MS-DOS Interface]            150

-------
Table 80 Typical HSSM-T Screen Messages
*
*
*
*
* *
* *
* *
* *
* *
* *
* *
* * *
*
*
*
*
*
*
*
*
* *
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
DATA INPUT
DATA INITIALIZATION
CALCULATING FLOATING POINT PRECISION
COMPUTATION BEGINNING FOR RECEPTOR 1
CALCULATING THE TOE TIME OF THE HISTORY
SEARCH ALGORITHM COMPLETED IN 6 ITERATIONS
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
AT
AT
AT
AT
AT
AT
AT
AT
AT
AT
AT
AT
18.
18.
33 .
48.
63.
78.
83 .
88 .
93 .
98.
103
108
18
44
41
38
35
32
32
32
32
32
.3
.3
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
{other similar messages omitted}
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION
COMPUTATION

OUTPUT FILE
BENZENE1
PLOT FILE:
BENZENE1
AT
AT
AT
AT
AT
AT
AT


TSG

PMP
553
603
653
703
753
803
853





.3
.3
.3
.3
.3
.3
.3





DAYS
DAYS
DAYS
DAYS
DAYS
DAYS
DAYS





COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED
COMPLETED





TSGPLUME END
151
[Appendix 1  The MS-DOS Interface]

-------
1.10 Plotting HSSM Results with HSSM-PLT
    The HSSM-PLT program is a graphics post-processor for the HSSM program.  HSSM-PLT provides
the model users with on-screen visualizations of the output as well as optional hard copies. All inputs are
made through a menu, enabling the user to concentrate on the model's results.  HSSM-PLT program is
written in Microsoft FORTRAN 77 version 5.0 and  uses the INGRAF version 5.02 library of FORTRAN
graphics routines.
1.10.1  Package Requirements

The plotting program is made up of the three files shown in Table 81. These are supplied on the HSSM-1-
d diskette and should be installed in the HSSM directory according to Appendix Table 41.
Table 81 Required Files for the HSSM-PLT Graphical Display Program
File
HSSM-PLT.EXE
CONFIG.PLT
SIMPLEX1.FNT
Function
The HSSM Graphical Display program
User supplied information about the printer
hardware of the system
The Sutrasoft font file for lettering the displays.
All three files must be present in the same subdirectory for HSSM-PLT to work properly.
1.10.2  Overview

    HSSM-PLT was written with the INGRAF graphics library.  The program displays a copyright notice
that will appear for approximately two seconds.  The Sutrasoft copyright notice is displayed in compliance
with the licensing agreement for the INGRAF graphics library. For more information about INGRAF contact:

                 Sutrasoft (The Librarian, Inc.)
                 10506 Permian Dr.
                 Sugarland, TX  77487
                 (713) 491-2088
                 FAX (713) 240-6883
HSSM-PLT displays a menu of choices which includes options to 1) exit the program, 2) configure output
devices, 3) select HSSM-KO  and HSSM-T results files for plotting,  and 4)  select graphs for display.
Options 2 through 4 display either screen messages or additional menus to guide the user.

    Table 82 lists the HSSM-PLT command sequence for graphing the results. The full details of the
procedures are described in the following sections.
[Appendix 1  The MS-DOS Interface]
152

-------
Table 82 Quick Summary of HSSM-PLT Commands
Step
0
1*
2
3
4
5
Command or Menu Item
see Table 41
Item 2
Item 3
Item 4
press P
Item 0
Action
Generate HSSM results
Select printer
Select HSSM-KO and HSSM-T
output files
Graph results
Print the graph which is
displayed
Exit
"The printer selection  is saved for future use of the program, so step 1 is executed only when the printer
is selected initially or changed; or when writing to disk files.

Title Screen

    This screen shows the title, version number, and authorship information for the program.  This data
stays on the screen until the user presses any key.

Menu Screen

    The Menu Screen contains the  user interface for all the HSSM-PLT program options. To make a
selection, the user presses the  indicated key for the desired selection. For example, to exit the program
a "0" (zero) key is pressed and the program ends. The legal  selections are 0 through 3 and any other key
strokes are ignored.

Menu Option 1:  Device Configuration

    The Device  Configuration  option allows  users  to select the  appropriate output  device  for his/her
system. The configuration data is stored in the config.plt file, so the user need only use this option when
running the program for the first time, when changing the printer, or when plotting to a disk file.  The current
output device is displayed  on the first line of Table 83. All of the supported output devices are displayed
with an index number. By entering the index number, the user selects an output device  from the displayed
list.
                                              153
[Appendix 1 The MS-DOS Interface]

-------
                        Table 83 Output Device Configuration Options
  THE  CURRENT OUTPUT DEVICE IS Postscript printer
  SELECT AN OUTPUT DEVICE

                   1 - EPSON 9-pin, narrow  carriage
                   2 - EPSON 24-pin, LQ series,  narrow
                   3 - EPSON 24-pin, LQ series,  wide
                   4 - NEC  Pinwriter, 24-pin,  narrow
                   5 - NEC  Pinwriter, 24-pin,  wide
                   6 - Okidata,  9-pin, narrow
                   7 - HP LaserJet/DeskJet  -  low res
                   8 - HP LaserJet/DeskJet  -  medium res
                   9 - HP LaserJet/DeskJet  -  high res
                  10 - HP PaintJet - 2 color,  low res
                  11 - HP PaintJet - 4 color,  med res
                  12 - HP PaintJet - 8 color,  high res
                  13 - HP PaintJet - 16 color,  high res
                  14 - Postscript printer
                  15 - HP -  HPGL plotter
                  16 - HP LaserJet III - HPGL/2  mode
                  17 - Houston  Inst DM/PL plotter

   ENTER DEVICE NUMBER  :
After the output device selection is made, the output port is assigned (Table 84).  The screen follows the
same format as for the device:  The current port is shown, followed by the possible port selections.  By
entering the index number, the user selects an output port from the displayed list.
[Appendix 1 The MS-DOS Interface]           154

-------
                              Table 84 Output Device Port Selection
   THE  CURRENT OUTPUT  PORT  IS LPT1 :
   SELECT  AN OUTPUT PORT
                      1  - PRN:
                      2  - LPT1:
                      3  - LPT2:
                      4  - COM1:
                      5  - COM2:
                      6  - AUX:
                      7  - FILE
   ENTER  PORT  NUMBER:
     Option 7 sends the graph to an HPGL format disk file rather than an output device. When this option
is selected, the user is prompted for a filename in addition to the port number. Note that only the last graph
written to file  is retained in the file.   If more than one graph  is desired to be written to a file, the
configuration must be reentered each time for each graph in order to change the name of the output file.

Menu Option 2:  Selecting Input Files

     Before graphing results, a set of HSSM results must be selected.  All of the necessary plot files are
read by HSSM-PLT and become available for drawing specific graphs.  If graphing  is attempted  before
selecting the plot files, a reminder to select a file is given.

The first message that appears on the screen is

ENTER SUBDIRECTORY PATH NAME
PRESS  TO USE  CURRENT DIRECTORY:

The user may then press  to use the  current  directory,  or  supply a  DOS path name  such as
c:\models\hssm\working
The user is prompted for a file name by the following message:

ENTER FILE NAME OR  *  FOR  A DIRECTORY
USE  THE  ROOT ONLY - NO EXTENSIONS:

Pressing  or an asterisk displays the current directory of HSSM-KO input files (files with extension
.DAT).  Entering the root name,  such as BENZENE, causes HSSM-PLT to begin reading the plot files.
HSSM-PLT adds the extensions to the root file name when it retrieves the plot files.  For this example, the
following messages were written to the screen:
                                              155            [Appendix 1  The MS-DOS Interface]

-------
READING FILE  c:\models\hssm\working\BENZENE.PLl ....   DONE
READING FILE  c:\models\hssm\working\BENZENE.PL2 ....   DONE
READING FILE  c:\models\hssm\working\BENZENE.PL3 ....   DONE
FILE c:\models\hssm\working\BENZENE.PMP  DOES  NOT EXIST
READING FILE  c:\models\hssm\working\BENZENE.HSS ....   DONE
PRESS ANY  KEY TO  CONTINUE

The plot files BENZENE.PL1, BENZENE.PL2, BENZENE.PL3 and the main result file BENZENE.HSS were read
successfully.  The HSSM-T plot file BENZENE.PMP did not exist as HSSM-T had not been run for this data
set.

Menu Option 3:  Selecting Graphs

    After the input file has been selected, graphs can be generated.  Option 3 from the main menu brings
up the graph menu.  If no  input file has been selected then an error message is displayed.  The  legal
entries for the graph menu are 0 - 7 and all other key strokes will be ignored. Each  of the graphs is
described in detail in the next section. Generally, after the graph is drawn on the screen, pressing any key
will bring the  user back to the graphics menu. However, if the user presses the 

key, the graph will be printed according to the data in the CONFIG.PLT file. [Appendix 1 The MS-DOS Interface] 155


-------
1.11  Graphical Presentation of HSSM Output
     Two basic types of graphs are produced by the DOS graphics post-processor. These are profiles
which present the spatial variation of a parameter at a given time, and histories which present the time
variation of a parameter at a given location.  The graphics present a visual summary of the output from a
successful HSSM simulation.  Results from each of the modules of HSSM are contained in one or more
of the graphs.  Table 85 gives information on each of the graphs provided.
Table 85 HSSM Graphics
Graph
Number
1
2
3
4
5
6
7
Title
Saturation Profiles
NAPL Front Position
History *
NAPL Lens Profiles
NAPL Lens Radius
History
Contaminant Mass Flux
History
NAPL Lens
Contaminant Mass
Balance
Receptor Concentration
Histories
HSSM Module
KOPT
KOPT
OILENS
OILENS
OILENS
OILENS
TSGPLUME
Description
Vadose zone liquid saturations from the
surface to the water table
Location of the NAPL front in the
vadose zone
Cross-section of the NAPL lens on the
water table
History of the radius of the NAPL lens
and the effective radius of the
contaminant
History of the mass flux from the NAPL
lens to the aquifer
History of the mass in the NAPL lens
History of the contaminant
concentrations at the receptor points
 Only the MS-DOS interface produces the NAPL Front Position History.
The graphs produced by HSSM-PLT are very similar to those produced by HSSM-WIN. Examples of the
HSSM-WIN graphs are shown in Section 4.8.
                                           157
[Appendix 1  The MS-DOS Interface]

-------
Appendix 2  DOS Example Problem
    In this Appendix, an example problem is presented that illustrates the use of the DOS interface.  This
problem is the same as the first example presented in Section 5. The complete set of input and output files
for this example is distributed on the HSSM-2 diskette.


2.1  Gasoline Arrival Time at the Water Table

    An emergency response and monitoring plan is being prepared for an  above ground storage tank
facility.  An estimate is needed of how long it would take gasoline to reach the water table and  what
monitoring frequency would be required to detect a leak before gasoline reaches the water table.  The soil
has been classified as a sandy  clay loam  soil.  In this example, the water  table lies at a depth of 5.0
meters.  All of the parameters for the model run are saved in the file  X1STF.DAT, which is found on the
example problems diskette HSSM-2.   PRE-HSSM can be used to page through  this file as the example
is studied.

    This problem needs the use of the KOPT module with  no dissolved contaminant.  A "per unit area"
simulation should be performed because only the transport time through the vadose zone is required. The
MS-DOS interface will be used to demonstrate how HSSM is used for this problem.  Of all the input data
required for the model, only  the following parameters  are required  for the  "KOPT only" simulation.
PRE-HSSM places necessary zeros in the data file for the unused parameters.
Screen 1.  Printing Option Switches

Only the output file production and KOPT options are used in the example simulation as shown in Table 86.
Table 86 Problem 1 Printing Option Switches
Parameter
IWR
IKOPT
ICONC
ILENS
ITSGP
Rationale
Produce Output files
Run KOPT
No dissolved constituent
Do not run OILENS
Do not write HSSM-T input file
Value
1
1
0
0
0
Screen 2 File Names

    The required file names are generated automatically when the data set is saved by PRE-HSSM.  The
stem for this data set is X1STF.
[Appendix 2  DOS Example]
158

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Screen 3 Run Title

Gasoline Release from an Aboveground Storage Tank Fac.
Gasoline Arrival Time at the Water Table
KOPT Simulation Only

Screen 4 Porous Medium Properties

    The porous medium properties listed on Screen 4 are estimated from Brakensiek et al.'s soil parameter
tabulation.  The values shown in Table 87 are taken from the tabulation reproduced in Appendix 3.1.
Table 87 Problem 1 Porous Medium Properties
Parameter
Air Entry Head, hce
Brooks and Corey's Pore Size
Distribution Index, K
Residual Water Content, 9wr
Porosity, TI
Value
46.3 cm
0.368
0.075
0.406
The hydraulic conductivity in cm/s of the system is then estimated from (Brakensiek et al., 1981)
                  K.
270 J-
=  8.68x1(T4c/77/s
(36)
where the air entry head is in cm. The value is then converted to the units of meters per day by multiplying
by 864 to give a Ks of 0.75 m/d.  From the basic soil property information, the following parameters are
determined (Table 88).
[Appendix 2  DOS Example]
                159

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Table 88 Problem 1 Hydraulic Conductivity and Capillary Pressure Curve Parameters
Parameter
Ratio of Horizontal to
Vertical Conductivity
Relative Permeability
Index
Air Entry Head, hca
Residual Water
Saturation, Swr
Rationale
Arbitrary value as this parameter is not used in
KOPT
The Brooks and Corey Model is used
The required units for HSSM are meters. This
parameter is entered on screen 7
HSSM requires saturation input rather than
"content" input
Value
5.0
1
0.463 m
0.18
(0.075 / 0.406)
Screen 5  Hydrologic Properties

    The parameters shown in Table 89  are used for the Hydrologic Properties screen.
Table 89 Problem 1 Hydrologic Properties
Parameter
Water Phase Density, pw
Water Phase Viscosity, uw
Recharge Input Type
Water Saturation, Sw(max)
Maximum Relative
Permeability During Infiltration,
I,
^rwfmax)
Depth of Water Table
Rationale
Standard value
Standard value
Specify Saturation
Specified water saturation
Assume 0.5
Arbitrary for this problem
Value
1 .0 g/cm3
1.0 cp
2
0.35
0.5
5 m
The depth to the water table is stated to be arbitrary because KOPT only treats the vadose zone above
the water table (and capillary fringe). The model results should be checked for the time at which the NAPL
front crosses the 5 meter depth.
[Appendix 2 DOS Example]
160

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 Screen 6 Hydrocarbon (NAPL) Phase Properties
Table 90 Problem 1 Hydrocarbon (NAPL) Phase Properties
Parameter
Oil Phase Viscosity, u0
Oil Phase Density, p0
Residual Oil Saturation
(vadose zone), Sorv
Oil Application Type
Rationale
Typical value for gasoline
Typical value for gasoline
Estimated
Select a constant head ponding
scenario
Value
0.45 cp
0.74 g/cm3
0.10
3
 Screen 7 Capillary Suction Approximation Parameters

     The capillary suction approximation parameters are used to add the effect of capillary suction on the
 infiltrating NAPL.  The air entry head of the Brooks and Corey model  (0.46 m) is entered on this screen.
 The surface tension of water is taken as 65 dyne/cm to account for the fact that the published values of
 surface tension are for very pure water. The NAPL surface tension is taken  to be 35.0 dyne/cm.


 Screen 8c Hydrocarbon (NAPL) Constant Head Ponding Boundary Condition

     Because the constant head release scenario was chosen on Screen 6, the constant head ponding
 boundary condition screen appears on screen 8.  The beginning time, ending time and ponding time are
 entered on this screen.  The release is assumed to begin at time of 0 days and end at a time of 1 day.
 During this interval the ponding depth is assumed to remain constant at 0.05 m (5 cm).


 Screen 11 OILENS Model Parameters, First Screen

     OILENS is not used in the  present simulation.  The radius of the source  must be specified, however,
 and this parameter is grouped with the OILENS parameters.  Only a "per unit area" simulation is desired
 for this example, so the  source radius is set to 0.5642 meters so that the resulting source  area is 1.00
 meters.  None of the other parameters on this screen need to be entered.
[Appendix 2 DOS Example]
161

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Screen 13 Simulation Control Parameters
Table 91 Problem 1 Simulation Control Parameters
Parameter
Simulation Ending Time
Maximum Solution Time Step
Minimum Time Between
Printed Time Steps
Ending Criterion
Minimum mass factor
Rationale
Simulate the release for 25 days, since gasoline
is a low viscosity fluid and can reach the water
table relatively rapidly in a permeable media.
Use a relatively small value, because only 25
days are simulated
Use a value smaller that the minimum solution
time step.
Stop the simulation at the specified time
Not used for this simulation
Value
25 days
0.1 day
0.05 day
1
0.01
Screen 14 Number of Profiles and Screen 15 Profile Times

    Use 5  profiles during the simulation. The times should be small, since the gasoline is expected to
reach the water table relatively rapidly.  Use times of 0.25,  0.5, 1.0, 2.0 and 5.0 days (6, 12, 24, 48 and
60 hours).
Model Results

    The model is executed by entering the command

HSSM-KO  X1STF.DAT
    The saturation profiles from the simulation are shown in Figure 40.  These profiles were drawn with
the HSSM-PLT program.  The depth of the sharp front increases with time and the first three profiles show
uniform NAPL saturations.  The last two profiles show varying NAPL saturations, because they occur at
48 and 60 hours which both are past the end of the release (24 hours).  Figure 41 shows the NAPL front
position.  This graph indicates that over the 25-day duration of the simulation, the NAPL does not go
deeper than about 3.6 meters.
[Appendix 2 DOS Example]
162

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                           SATURATION PROFILE
       0.0
       0.5
        1.0
        1.5
       2.0
       2.5
       3.0
_

-

;
I i
L \ V
_ \\ j
\\ >
\\
	 J
i i i
_

-
-
-

         0.00
 0.35
Total Liquid Saturation
1.00
 Figure 40 Saturation profiles
                              NAPL FRONT POSITION HISTORY

                        Gasoline Release from an Above Ground Storage Fac.
  I
  f
                        5.0
          10.0          15.0
             Time (Days)
20.0
25.0
Figure 41  The front position
[Appendix 2  DOS Example]
                        163

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      With complete confidence in the accuracy of the input data, it could be assumed that the gasoline
  never reaches the water table.  However, most of the model parameters used in this example have been
  estimated from published tabulations.   Rather  than  accepting the results of one simulation as being
  authoritative, several simulations should be run in  order to get some feel for the effects of parameter
  variability.   If the hydraulic conductivity was in fact  10 times greater than the average value of 0.75 m/d,
  the gasoline would flow deeper  into the subsurface.  Because of the constant head ponding condition
  assumed for this  case, the gasoline would also flow faster.  The constant head ponding condition does
  not specify the volume of gasoline which enters the  soil; it only indicates that enough gasoline is supplied
  to maintain the 0.05  m ponding depth for one day.  Figure 42 shows the NAPL front position when the
  hydraulic conductivity is 7.5 m/d.   By 25 days,  the gasoline would reach 24 meters deep, if not for the
  water table 5.0 meters deep.  From the X2STF.HSS file, the depth of 5 meters was reached within 9.8 hours.
                                 NAPL FRONT POSITION HISTORY

                             Gasoline Release from an Above Ground Storage Fac.
           24.0 F
           16.0 -
    I
    *
             0.0
5.0
10.0          15.0
    Time (Days)
                                                                 20.0
                                                   25.0
Figure 42  Storage tank facility example with increased conductivity
      This example has focussed on the role of the hydraulic conductivity in determining the depth of the
  gasoline.  The effect of variation in other parameters can likewise be demonstrated.  Some of the other
  uncertain  parameters  are  the assumed release condition,  moisture  content,  and capillary pressure
  parameters.
  [Appendix 2  DOS Example]
                      164

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Appendix 3   Sources of  Parameter Data
    The data that are used in models are of crucial importance for determining the quality of the results
and their applicability to the  real world problems they are  intended to simulate.  Often where  model
applications fail to be realistic, the failure is due to data limitations and lack of fundamental understanding
of site specific transport processes, both hydrologic and chemical. The following section does not address
directly all of these issues, rather it describes the uses and limitations of estimated parameter values.  The
discussion  below is intended to highlight the importance  of several HSSM  input parameters.  Further
detailed information on parameter values is given in Section 4.6 for HSSM-WIN  and in  Appendix 1 for
HSSM-DOS.  For convenience, both of these sections contain the same information.

    Unarguably, the best sources for parameter values are site- and pollutant-specific data obtained under
an appropriate  quality assurance/quality control program.  There  is no  substitute for measured  data.
Unfortunately such data are not always available and  recourse must be made to  estimated or tabulated
parameter values. When this type of data is used for modeling, it must be  recognized that very significant
uncertainty is being introduced into the simulation results. The model results may be useful, however, for
addressing such issues  as comparison of the effects of various pollutant  or soil properties on transport.
For example, given a soil type, perhaps defined by parameters selected from a nationwide  tabulation, how
does the transport of benzene compare with that of toluene?  HSSM model results may provide some
understanding of relative transport effects. Because of practical and theoretical limitations in understanding
subsurface transport, site specific prediction of future contaminant behavior  is questionable with any model.


3.1  Soil Properties

    Of primary importance are the soil properties:  saturated hydraulic conductivity, Ks, and the water/air
capillary pressure curve,  PC(S), (a.k.a. the moisture characteristic curve or the moisture retention curve).
Note that the term "saturated hydraulic conductivity" refers to the conductivity to water as defined by Darcy's
Law:
where qw is the water flux, Ks is the hydraulic conductivity, and -dh/dl is the hydraulic (head) gradient. The
capillary pressure curve depends on some of the same features of the porous medium as does Ks. These
features include the grain and pore size distribution, and the sand, silt, clay and loam fractions. There may
be relationships between Ks and parameters describing the PC(S) curve (Brutsaert, 1967; Brakensiek et al.,
1981; Carsel and Parrish, 1988).
                                              165         [Appendix 3  Sources of Parameter Data]

-------
     Brooks and Corey (1964) presented the following power-law relationship between capillary pressure
and reduced saturation
                                                                                          (38)
where Swr is the irreducible (residual) water saturation, X is called the pore size distribution index, and hce
is the air entry head.  In practice Swr, X, and hce are parameters which are fitted to an experimental data
set.

    van Genuchten (1980) proposed a similar model


                                  Q*~Qwr   =  f—i—r                           (39)
                                  0m - „   J  (A,  + 1)(A. +  2)

where C is a constant taken as 270 by  Brakensiek et al. (1981) and as 21 by Rawls et al. (1983).  Thus
this tabulation  consists of measured PC(S)  data fitted to the  Brooks and Corey model and calculated Ks
values.  Table 92  shows Brakensiek et al. (1981) results with their statistical distributions of parameter
values.  For each  parameter, Brakensiek et al. chose the most suitable distribution and presented their
result in terms of means and standard deviations of transformed distributions (e.g., log normal). Table 92
shows the  untransformed values which would be used directly to generate a capillary pressure curve.
These values were developed by using the statistical distributions given  by  Brakensiek et al. (1981) to
generate a distribution of each parameter.   The mean values of the distributions were determined and are
shown in Table 92. All of the values of the pore size distribution index, X, are low,  which indicates wide
pore size distributions (well sorted materials).   Some sands, in particular, may be more uniform and be
better represented by a higher value.   Brooks and Corey parameters for several sands whose capillary


[Appendix 3 Sources of Parameter Data]        166

-------
pressure curves were measured at RSKERL are presented in Table 93.  These examples have higher
values than does the tabulation.
Table 92 Average Soil Properties Determined from
Brakensiek et al. (1981)
Soil Texture Class
(number of samples)
Sand (19)
Loamy Sand (69)
Sandy Loam (166)
Loam (83)
Silt Loam (199)
Sand Clay Loam (129)
Clay Loam (112)
Silty Clay Loam (175)
Silty Clay (26)
Clay (108)
A,
0.573
0.460
0.398
0.258
0.216
0.368
0.283
0.178
0.212
0.214
hce
(cm)
35.3
15.9
29.2
50.9
69.6
46.3
42.3
57.8
41.7
64.0
T!
0.349
0.410
0.423
0.452
0.484
0.406
0.476
0.473
0.476
0.475
9wr
0.017
0.024
0.048
0.034
0.018
0.075
0.087
0.054
0.085
0.106
Table 93 Brooks and Corey Parameters for Selected Sands
Sand
Lincoln
Oil Creek
Traverse City
c109
c190
hoe
(cm)
42.8
53.9
24.0
23.7
10.2
K
(*)
1.69
4.19
2.43
3.86
4.65
^wr
n
0.09
0.04
0.0
0.01
0.08
In the Brakensiek et al. tabulation, sand has a higher air entry value (35.3 cm) than loamy sand (15.9 cm).
This suggests that  Brakensiek et al.'s sand data are dominated by relatively fine sands of wide pore size
distribution.  Notice also that the clay type has a lower air entry value (64.0 cm) than does the silt loam
(69.6 cm).  In some of the texture classes only a small number of samples were  used to generate the
parameter values,  which is a  probable  reason for  the  anomalous parameters.   As  a result,  the
aforementioned features of the tabulation suggest that it may only be useful as a rough guide for estimating
parameter values.
                                             167
[Appendix 3 Sources of Parameter Data]

-------
    Carsel and Parrish (1988) presented a tabulation of data based on van Genuchten's (1980) model and
soil texture data.   Ks, a, n, 6wr, and 6m were estimated from regression equations developed previously
by Rawls and Brakensiek (1985)   for Brooks and Corey  parameters.    Carsel and Parrish  used an
asymptotic approximation to convert the Brooks and Corey hce and A, values to van Genuchten a and n
values.   The results of the Carsel and Parrish (1988) tabulation are reproduced in Table 94 for the
saturated and residual water contents, Table 95 for the parameters n and a, and Table 96 for hydraulic
conductivity.
Table 94 Descriptive Statistics from Carsel and Parrish (1988) Data Set
Soil type
Clay*
Clay Loam
Loam
Loamy
Sand
Silt
Silt Loam
Silty Clay
Silty Clay
Loam
Sand
Sandy Clay
Sandy Clay
Loam
Sandy
Loam
Saturated Water Content 0m
sample size
400
364
735
315
82
1093
374
641
246
46
214
1183
mean
0.38
0.41
0.43
0.41
0.46
0.45
0.36
0.43
0.43
0.38
0.39
0.41
standard
deviation
0.09
0.09
0.10
0.09
0.11
0.08
0.07
0.07
0.06
0.05
0.07
0.09
Residual Water Content 0r
sample size
353
363
735
315
82
1093
371
641
246
46
214
1183
mean
0.068
0.095
0.078
0.057
0.034
0.067
0.070
0.089
0.045
0.100
0.100
0.065
standard
deviation
0.034
0.010
0.013
0.015
0.010
0.015
0.023
0.009
0.010
0.013
0.006
0.017
[Appendix 3 Sources of Parameter Data]
168

-------
Table 95 Descriptive Statistics from Carsel and Fairish (1988) Data Set
Soil type
Clay*
Clay Loam
Loam
Loamy
Sand
Silt
Silt Loam
Silty Clay
Silty Clay
Loam
Sand
Sandy Clay
Sandy Clay
Loam
Sandy
Loam
n
sample size
400
364
735
315
82
1093
374
641
246
46
214
1183
mean
1.09
1.31
1.56
2.28
1.37
1.41
1.09
1.23
2.68
1.23
1.48
1.89
standard
deviation
0.09
0.09
0.11
0.27
0.05
0.12
0.06
0.06
0.29
0.10
0.13
0.17
«, (m-1 )
sample size
400
363
735
315
82
1093
126
641
246
46
214
1183
mean
0.80
1.9
3.6
12.4
1.6
2.0
.50
1.0
14.5
2.7
5.9
7.5
standard
deviation
1.2
1.5
2.1
4.3
0.70
1.2
0.50
0.60
2.9
1.7
3.8
3.7
169
[Appendix 3 Sources of Parameter Data]

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Table 96 Descriptive Statistics from Carsel
and Parrish (1988) Data Set
Soil type
Clay*
Clay Loam
Loam
Loamy
Sand
Silt
Silt Loam
Silty Clay
Silty Clay
Loam
Sand
Sandy Clay
Sandy Clay
Loam
Sandy
Loam
Hydraulic Conductivity Ks, (m/d)
sample size
114
345
735
315
88
1093
126
592
246
46
214
1183
mean
0.048
0.062
0.25
3.5
0.060
0.11
0.0048
0.017
7.1
0.029
0.31
1.1
standard
deviation
0.10
0.17
0.44
2.7
0.079
0.30
0.026
0,046
3.7
0.067
0.66
1.4
* The clay type represents an agricultural soil with clay content of 60% or less.
    As a third approach to estimating the soil hydraulic properties, Rawls and Brakensiek (1985) developed
regression equations for the Brooks and Corey parameters. The required data for use of the regressions
are the percent sand, PS, the percent clay, PC, and the porosity, T\.  The general form of the regression
equations is
                                                                                          (42)
[Appendix 3 Sources of Parameter Data]
170

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To apply the regression equations, the percent sand must be between 5 and 70 and the percent clay must
be between 5 and 60.  Table 97 gives the values of the regression coefficients for estimating the residual
water content, 6r, the natural log of the hydraulic conductivity, Ks, entry head, hce, and pore size distribution
index, A,.  Appendix  5 describes a utility program called SOPROP which uses the regression  equations
to estimate these hydraulic properties.
Table 97 Regression Coefficients from Rawls and Brakensiek (1985)
Coefficient
b0
bioo
boio
booi
b200
'-)020
b002
bno
b101
bon
b210
b021
b201
b120
b012
b202
b022
ln( K.)
-8.96847
--
-0.028212
19.52348
0.00018107
-0.0094125
-8.395215
—
0.077718
-
0.0000173
0.02733
0.001434
-0.0000035
—
-0.00298
-0.019492
er
-0.0182482
0.00087269
0.00513488
0.02939286
-
-0.00015395
—
—
-0.0010827
-
-
0.00030703
-
—
-0.0023584
—
-0.00018233
In (hce)
5.3396738
—
0.1845038
-2.48394546
-
-0.00213853
—
—
-0.0435649
-0.61745089
-0.00001282
0.00895359
-0.00072472
0.0000054
0.50028060
0.00143598
-0.00855375
ln(X)
-0.784281
0.0177544
-
-1.062498
-0.00005304
-0.00273493
1.11134946
~
-0.03088295
~
-0.00000235
0.00798746
-
—
-0.00674491
0.00026587
-0.00610522
    Before continuing, the accuracy of using tabulated "average" parameter values is illustrated through
a comparison of measured capillary pressure curves with the average for sand.   Figure 43 shows the
average curve for Brakensiek et al.'s sand and data from several sands measured at RSKERL using a
technique developed by Su and Brooks (1980). These sands are not meant to be a representative sample,
but were materials used  in several experiments.  The class "sand" is seen to contain much variability and
the average curve does not necessarily represent any particular sand.

    The 20/30,  C109 and "Texas" sands  are  commercial  products with relatively uniform pore size
distributions.  The curves appear almost as step  functions. The TCS sand from Traverse City, Michigan,
                                              171
[Appendix 3 Sources of Parameter Data]

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and the Lincoln and Oil Creek sands, both from Pontotoc County, Oklahoma, are natural materials. Oil
Creek has a uniform pore size distribution and is not very representative of sands in general. The Lincoln
has a wider distribution of pore sizes than the others and has a less abrupt curve. The Carsel and Parrish
                                                              Sand (Brakensiek et al., 1981)

                                                              Sand(Carsel et al., 1988)

                                                         A    C109

                                                         O    20/30

                                                         D    TCS

                                                         •    Lincoln

                                                         •    Oil Creek

                                                              Texas
                                                                    oo    oo
  Figure 43 Comparison of average capillary pressure curves with measured data

average curve has a much lower air entry head, suggesting that their data set was dominated by coarse
sands. Data, such as shown in Figure 43, may be fitted to either of the capillary pressure models by non-
linear curve fitting procedures.  The model called Belention C_urve (RETC) by van Genuchten et al. (1991)
is a special purpose program for fitting these models to  data.
[Appendix 3 Sources of Parameter Data]
172

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3.2  NAPUWater Partition Coefficient

    Partitioning of chemicals constituents which compose the NAPL between the NAPL and water phase
is another phenomena of major  importance.  In  HSSM this partitioning is assumed to follow  a  linear
equilibrium relationship
                                             =   K
                                (43)
where c0 is  the concentration in NAPL,  cw is the concentration in water, and K0 is the dimensionless
NAPL/water  partition coefficient.  The magnitude of this coefficient has a major influence on the model
results as it partially determines how much of the chemical is released from the NAPL to the water.

    K0 depends on the composition of the NAPL. Based on their work with 31 gasoline samples, Cline
et al. (1991) suggest that Raoult's Law can be used to estimate K0 for gasoline mixtures.   Raoult's Law
provides an estimate of K0 for the kth constituent of a  NAPL that is composed of a total of j constituents as
                                                                                         (44)
where  oo, is the molecular weight of the jth constituent (g/mol), c0| is the concentration of the jth constituent
in the oil phase (g/L), sk is the solubility of species k in water (g/L), and yk is the activity coefficient of the
kth species.   The activity coefficients  equal  1.0 for ideal solutions.   Equation  (44) indicates that the
magnitude of K0 depends on the composition of the NAPL, so it is not possible to tabulate values of K0 for
universal application. Table 98 contains partitioning  and solubility data for several organic compounds of
interest.
Table 98 Partitioning Characteristics ('Mercer et al., 1 990, "Cline et al., 1 991 , 'Chemical
Information Systems, 1994)
Constituent
benzene3
ethylbenzene3
toluene8
m-xylenea
o-xylenea
p-xylenea
MTBE methyl fert-buty! ether
Water Solubility
(mg/L)
1750
152
535
130
175
196
48000b
Koc
(ml_/g) or (L/kg)
83
1100
300
982
830
870
11.2°
                                              173
[Appendix 3 Sources of Parameter Data]

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    The compositional dependence of K0 presents a problem in that K0 varies with the composition of the
NAPL:  gasoline, diesel, fuel, oil, etc.  In order to apply equation  (44) the concentration Coj of each
component or general class of components in the NAPL mixture must be known.  Further, as more soluble
components of the NAPL are lost, K0  may change.   Cline et al.'s (1991)  measured partition coefficients
for benzene and toluene, however, showed only a slight variation with  concentration.

    Baehr and Corapcioglu (1987) used a simplified mixture to represent gasoline which  is shown in
Table 99.  From this composition several K0's are calculated from equation (44) and are listed in Table 100.
Note that  benzene, toluene and o-xylene are all hydrophobic, but the degree  of hydrophobicity varies
widely.  Included in the tables are data for methyl terf-butyl ether (MTBE), an octane enhancer which may
occupy up to 15% of gasoline  by volume (Cline et al., 1991).  The values calculated by using the mixture
of Baehr and Corapcioglu (1987) compare favorably with the values measured by Cline et al.(1991).
Table 99 Pseudo-Gasoline Mixture (Baehr and Corapcioglu, 1987)
Constituent
benzene
toluene
xylene
1-hexene
cyclohexane
h-hexane
other aromatics
other paraffins (C4-C8)
heavy ends (> C8)
Initial COJ
(g/cm3)
0.0082 (1.14%)
0.0426 (6.07%)
0.0718(10.00%)
0.0159 (2.22%)
0.0021 (0.29%)
0.0204 (2.84%)
0.0740 (10.31%)
0.3367(46.91%)
0.1451 (20.21%)
Molecular
weight
<°i
78
92
106
84
84
86
106
97.2
128
[Appendix 3 Sources of Parameter Data]
174

-------
Table 100 Fuel/Water Partition Coefficients Measured by Cline et al. (1991)
compared with K,, values calculated from Corapacioglu and Baehr (1987) in
parentheses.
Constituent
MTBE
methyl ferf-butyl ether
benzene
toluene
ethylbenzene
m-,p-xylene
o-xylene
n-propylbenzene
3-,4-ethyltoluene
1 ,2,3-trimethylbenzene
Average
K0
15.5
350 (312)
1250 (1202)
4500
4350
3630 (4440)
18500
12500
13800
Coefficient of
variation
% dev.
19
21
14
13
12
12
30
19
20
    Assuming ideality, Cline et al. (1991) used a further approximation to Raoult's law, which can be stated
as
                                              1 X106 ±°
                                                        ,,o
                                                                                          (45)
where p0 is the NAPL phase density (g/ml), co° is the average molecular weight of the NAPL phase (mol/g),
cok is the molecular weight of  constituent k (mol/g), and sk is the solubility of the  constituent of interest in
g/l.  Cline et al.(1991) demonstrated that this approximation provided an adequate fit to the measured
partition coefficients from their 31 samples of gasoline.   Cline et al. used an average gasoline density of
0.74 g/ml and average gasoline molecular weight of 100-105 g/mol.  The measured partition coefficients
showed approximately 30% variation, and the fitted Raoult's  law relationship adequately represented the
trend of  the values on a log-log  plot.  Appendix 6  describes a  utility program called RAOULT which
performs the Raoult's  law calculations using equations (44) and (45).

    In addition to the partition coefficient, the composition of the NAPL is important  in determining the
constituent concentrations in  the  contaminated  ground water.    Since  the water phase concentration
                                              175
[Appendix 3 Sources of Parameter Data]

-------
depends on the oil phase concentration, the composition of the NAPL dictates both the partition coefficient
and the amount of constituent that is available for contamination of the water phase.

3.3  Estimation of the  Maximum NAPL Saturation in the Lens

    When LNAPL accumulates in a lens it displaces water from the capillary fringe and from below the
water table. Not all  of the wetting phase is displaced, and the LNAPL saturation increases from the base
of the lens towards  the top.  The distribution  of LNAPL near the water table is determined by the forces
of gravity and  capillarity, and by the dynamics of water table fluctuations.  The usual way of monitoring
LNAPL thickness is through observation wells.   Under conditions where the water table is static, these
observation wells record the true energy distribution within the formation, independent of capillary forces.
Because the observation wells  have a large radius, the capillary pressure is negligible.  When the water
table fluctuates,  such as in a tidal  environment, the observation well LNAPL thickness may show little
resemblance to the actual thickness within the formation (Kemblowski and Chiang, 1990). HSSM assumes
that the water table  is static and requires that an average  LNAPL saturation within the lens be estimated.
This appendix outlines the method for estimating the average LNAPL saturation and Appendix 7 describes
the NTHICK utility for performing these calculations.

    The maximum LNAPL phase saturation in the lens is determined through approximation of the LNAPL
distribution in the capillary fringe. The soil moisture  retention curve gives the distribution of water in a two-
phase, air-water  system, which using the Brooks and Corey model  is
                                                                                         (46)
where z is measured upward from the water table and 0W is the reduced water saturation.  At elevations
below the entry head, hce, 9W is equal to one.   Equation (46) gives the reduced water saturation as a
function of elevation above the water table under conditions of vertical equilibrium.   To apply this model
to a multiphase system that  includes free  product at the water table, one must determine how the
equilibrium behavior for an air-LNAPL and LNAPL-water system can be estimated from those for the air-
water system.  If changes in the soil structure (swelling, etc.) are neglected, then the difference in behavior
from one fluid system to another can be attributed only to differences in fluid properties. The development
of expressions for relationships between the fluid distributions begins with the Brooks and Corey parameters
for the air-water system: hce, /t and Swr.  For multiple fluid systems the subscripts W, 'o' and 'a' designate
the water, NAPL and air phases.  The first generalization of equation (46) gives relationships for the entry
pressures in a system composed of fluids i and j
                                                                                         (47)
                                            °aw                 °aw
where pblj is the bubbling (or entry) pressure in a system composed of fluids i and j, a,, is the interfacial
tension  between fluids i and j, and g is the acceleration of gravity.  pbaw is the entry pressure that is
associated with the entry head, hce.  Equation  (47) follows from the assumption that the maximum pore


[Appendix 3 Sources of Parameter Data]        1 75

-------
size remains constant and that the entry pressure depends only on the surface tension.  The capillary
pressure between fluids i and j, pclj Is defined by
                                     Pea   =   ^9,j9z                               (48)
where Aplj is the difference in density between fluids i and j, and the datum z is chosen at the elevation
where the capillary pressure vanishes.  This gives
                            e    =     V"™0u     =                                 (49)
                             ;

for z > hcl| where j is the wetting phase and
                                    h       =        slL                              (50)
                                     09 J
Similar scaling relationships were introduced by Leverett (1941) and later used by van Dam (1967), Schiegg
(1985), Parker et al. (1987), Gary et al. (1989), Demond and Roberts (1991), and others.  For the air-NAPL
system Apao may be taken as equalling p0, because of the low density of air.
                                             177        [Appendix 3 Sources of Parameter Data]

-------
    In a  three-phase  system,  water is taken as the  wetting fluid,  the  LNAPL is  taken as being of
intermediate wettability, while air is the nonwetting fluid.  The implication  of this wettability order is that
water resides in the small pores, LNAPL in the intermediate pores and air in the largest pores. Since the
capillary pressure relationships are defined for two-fluid pairs, one has to work with the fluid pairs separately
in a three-phase system. This approach has been developed by Leverett (1941) and adopted by Schiegg
(1985), Parker et al. (1987) and others.  The  Leverett assumption is that the water saturation in a three
phase system depends only on the NAPL-water capillary pressure, while the total liquid saturation, S, = Sw
+ S0,  is a function of the interfacial curvature of the air-NAPL interface, independent of the  number or
proportions of  liquids contained in the porous medium.  With the  Brooks and Corey power-law retention
model, these relationships may  be written as
                            0,
                                                               ow
and


                                                                 T                       (52)
                                                               ao
where zow and zao are the elevations at which the corresponding capillary pressures would vanish.

    Since the LNAPL residual saturations above and below the water table may be different, the scaling
functions for the reduced saturations are
                                                                                          (53)
and
                                                                So ~ Swr ~ Sorv
                                1
where Swr is the water retention or "field capacity", and Sors and Sorv are the residual NAPL saturations in
the saturated and vadose zones, respectively.

    Together, equations (51) through (54) determine the fluid distribution near the water table.  What is
still lacking is a determination of the capillary pressure datums zow and zao.  However, these are the levels
at which one would find the fluid interfaces in observations wells where capillary forces are absent, and the
problem reduces to the standard manometer problem from hydrostatics.  Let the elevation zaw be that of
the free water interface in the absence of NAPL, while zao and zow are the corresponding elevations when
a NAPL layer  of apparent thickness b0 and density p0 is present. A  simple calculation  from hydrostatics
shows that

[Appendix 3 Sources of Parameter Data]         1 73

-------
                                                      -^ b0                             (55)
                                                      Pw
 where pw is the density of water.  One also finds that
                                T      T             W     0  U
                                zao ~  zaw   =    	  bo
    The total thickness of the hydrocarbon present in the free product region, exclusive of any hydrocarbon
trapped above or below the water table,  is found by integrating the  difference between the total liquid
content and the water content over the free product region:
                                         =   f(Qt-Ow)dz                            (57)
This usage of the NAPL layer thickness, D0, corresponds to that of Schwille (1967) who used it for the ratio
between the amount of NAPL spreading laterally on the groundwater surface and the area occupied by it.
Other authors have referred to the NAPL layer thickness as that which may be observed visually in a
laboratory apparatus.

    The  total  liquid and water contents are estimated using a modified form of the Brooks and  Corey
capillary pressure function with hc equal to the elevation above the  fluid interface as seen in an observation
well.  The elevation for the water content is measured from the level  of the hydrocarbon-water interface
while the elevation for the total liquid content is measured from the level  of the air-hydrocarbon interface
in the well.  The nonwetting phase entry  heads for the hydrocarbon-water, and air-hydrocarbon fluid
systems,  hceow and hceao respectively, are estimated from
                                              179        [Appendix 3  Sources of Parameter Data]

-------
                                               ,    K""°:                               (58)
                                               (Pu, ~~  Prt) Oau,
                                               \~ W   • Of  oW
and
                                                 Pw°ao
                                    ceao                  ce
                                                        h
                                                        "
where hce is the normal air entry head for the air-water system. With equations (51) to (54) the integral in
equation (57) can be evaluated.  The result may be written as


                                   D0    =   a  + p(d0)&0                             (60)

where
            „   -     LL   .       -..,    Sors]hceow   [^-(1    &wr   ^orvjl^ceao]
                                               1-A
                                            1  — Y
                                                                                         (62)
                                            T, (1  -
                                                                      b0
                                                                                         (63)
Similar results have been presented by Farr et al. (1990) and Parker and Lenhard (1989).  In equation (60),
b0 is the hydrocarbon layer thickness one would see in a large capillary (observation well), and Sorv and Sorg
are the residual hydrocarbon saturations above and below the lens,  respectively.  The function P(b0) has

[Appendix 3 Sources of Parameter Data]         -\ QQ

-------
only a weak dependence on b0, especially at moderate to large LNAPL layer thicknesses. This implies that
the relationship between D0 and b0 is nearly linear. The ratio of the averaged formation thickness, D0, and
the observation well thickness, b0,  gives the average NAPL saturation in the lens
                                                           b0
                                                                                         (64)
                                             181         [Appendix 3 Sources of Parameter Data]

-------
Appendix 4   Approximate  Conversion  of  Capillary Pressure  Curve
Parameters
    KOPT and OILENS are designed primarily to use Brooks and Corey's model, however, HSSM-KO
allows the entry of van Genuchten capillary pressure parameters. These are not used directly by the model
but rather are automatically converted into approximately equivalent Brooks and Corey parameters by a
method proposed by Lenhard et al. (1989). Since van Genuchten's model is not equivalent in form to the
Brooks and Corey model, the parameters are not exactly equivalent. The conversion is given by
                                        m
                                      ^-m
   (1  -  0.5 m)
(65)
                              '£»

                                       a
                                                                                 (66)
where
                                    IB  -  1-
                                       (67)
and S. is defined by Lenhard et al.'s (1989) empirical relation

                           S,   =  0.72  -  0.35   exp(-n4)
                                       (68)
Figure 44 and Figure 45 compare the Brooks and Corey model with van Genuchten's model for equivalent
parameter sets. The equivalent parameter sets are shown in Table 101.
Table 101 Equivalent Capillary Pressure Curve Parameters
Soil Texture
Sand
Sandy Clay loam

em
0.43
0.39

er
0.0443
0.1121
Brooks and Corey
K
1.1852
0.3887
hce
4.628
8.0941
van Genuchten
n
2.7953
1.4321
a
0.1417
0.0858
[Appendix 4 Capillary Parameters]
182

-------
    150
    100
     50
                                                  SAND
                                                                                  VG





                                                                                  BC
                          0.1
   0.2




6 (cm'/cm3)
                                                                 0.3
0.4
Figure 44  Comparison of equivalent Brooks and Corey and van Genuchten parameters for sandy soil
                                             183
                    [Appendix 4  Capillary Parameters]

-------
                                           SANDY CLAY LOAM
   1000
    800 -
    600 -
o
      0.1
   Figure 45 Comparison of equivalent Brooks and Corey and van Genuchten parameters for sandy clay loam
   soil
   [Appendix 4  Capillary Parameters]
184

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Appendix 5  The Soil  Property Regression Utility (SOPROP)
    The SOPROP utility is  provided with HSSM in order to estimate soil properties from the set of
regression equations developed by Rawls and Brakensiek (1985). SOPROP is executed from the DOS
prompt by the command:

SOPROP

No input or output files are required as all the input to and output from the utility are directed to the screen.
The user is prompted for 1) the percent sand, PS , 2) the percent clay, PC, and 3) the porosity, r|.  The
hydraulic conductivity and Brooks and Corey parameters are calculated and then written to the screen as
shown in Table 102.  Recall that the data upon which the regression equations are from agricultural and
forest soils; so the SOPROP output is appropriate for similar soils with percent sand between 5.0 and 70.0
and percent clay between 5.0 and 60.0.
                             Table 102 SOPROP Screen Output
      *********************************************
      Estimate of  soil hydraulic properties
      from Rawls and Brakensiek  (1985)
      regression equations

      for  the soil with:
         70.0000 percent sand
           5.0000 percent clay
            .3500 porosity
      the  estimated hydraulic parameters are:
      hydraulic conductivity             .4257 m/d
      Brooks and Corey parameters:
      residual water saturation          .1403
      air  entry head                      .1754 m
      pore size distribution index       .4902
            ***successful execution of  soprop
    The range of parameter values that are produced by these equations are shown in Table 103.  One
extreme occurs when the percent sand is at its maximum value (70%)  and the percent clay is at its
minimum value (5%).  The hydraulic conductivity, as expected, is highest (0.92 m/d) with highest porosity
(0.40).  Hydraulic conductivities greater than this value are out of the range of the tabulated parameters
which form the basis for the regression equations. Likewise another extreme occurs when the percent sand
is a minimum (5%) and the percent clay is a maximum (60%).  With low porosity (0.30) the conductivity is
low (2.3 x 10"7 m/d) and the air entry head is high (6.4 m).
                                          185            [Appendix 5  The SOPROP Utility]

-------
Table 103 Range of parameter values produced by the Rawls and Brakensiek (1985) regression
equations
SOPROP input parameters
Percent
sand
70
70
70
70
5
5
5
Percent
clay
5
5
5
5
60
60
60
Porosity
0.40
0.35
0.30
0.25
0.50
0.40
0.30
SOPROP results
K8
(m/d)
0.92
0.43
0.18
0.065
1.5x 10'3
1.3x 10'5
2.3 x 1Q-7
Swr
0.12
0.14
0.18
0.22
0.21
0.16
0.023
hoe
(m)
0.14
0.18
0.24
0.33
1.3
2.9
6.4
X
0.46
0.49
0.53
0.58
0.12
0.053
0.015
[Appendix 5 The SOPROP Utility]
186

-------
Appendix 6  The  RAOULT  Utility

    Calculation of the NAPL/water partition coefficient, K0, is simplified through the usage of the RAOULT
utility.  This utility uses the composition of the hydrocarbon phase for determining the partition coefficient
with equations (44) and (45). The utility is executed by typing

RAOULT

at the DOS prompt.  The program automatically reads a default data set for gasoline and begins execution
of the program.

    Table 104 shows the  default data set screen messages written by RAOULT.  The data is taken from
Baehr and Corapcioglu (1987) and is contained in the file RAOULT.DAT. The data file may be edited or the
data changed interactively by entering a  V at the "Change the input data ?" prompt.  The procedures for
changing the data are given below.
Table 104 RAOULT Utility Main Screen





Raoults Law Partitioning Calculation
Chemical

1 benzene
2 toluene
3 xylenes
4 1-hexene
5 cyclohexane
6 n-hexane
7 other aromatics
8 other paraffins
9 heavy_ends
Change the input data ?
Solubility
(mg/L)
1750.0000
535.0000
167.0000
. 0000
.0000
. 0000
.0000
.0000
.0000
(Y or N)
Cone .
(g/cm3)
.0082
.0426
.0718
.0159
.0021
.0204
.0740
.3367
.1451

Molecular
Weight
78 . 0000
92.0000
106.0000
84.0000
84.0000
86 . 0000
106.0000
97.2000
128.0000

Activity
Coefficient
1.0000
1.0000
1.0000
1.0000
1.0000
1.0000
1 . 0000
1.0000
1. 0000

    With no changes in the input data set (answer 'N' to the "Change the input data ?" prompt, see
Table 105), RAOULT determines the density of the hydrocarbon and its average molecular weight. These
quantities are used to calculate the hydrocarbon/water partition coefficient using equations (44) and (45).
The two results are similar and  are denoted as determined by the composition  basis and the average
molecular weight basis, respectively. The user has the option of calculating partition coefficients for  other
constituents or exiting the utility.
                                             187
[Appendix 6 The RAOULT Utility]

-------
          Table 105 Sample RAOULT Calculation for the Benzene Constituent of Gasoline
  Change the  input data ?  (Y or N)
  N

      Hydrocarbon density     =       .7168
      Avg. Molecular  Weight  =   104.0458
  Select  constituent  of interest by  number
  1
      Calculated Hydrocarbon/Water  Partition Coefficient:
      Composition basis:
         311.6757
      Average  molecular weight basis:
         307.0647
  Exit  ?  (Y or  N)
  Y

           *** successful execution of raoult
    The default hydrocarbon composition can be changed by direct editing of the RAOULT.DAT data file.
The default data set is shown in Table 106. The data set is mostly free format input, with the exceptions
noted.  The first line contains the number of chemicals composing the hydrocarbon; in this case nine.
RAOULT will accept 200 chemicals composing the hydrocarbon phase.  The rest of the lines contain the
data for each chemical. The chemical name is given first and must be contained within the first 20 spaces
of each line.  The name may contain any combination of letters, numbers, or other keyboard characters;
it may not, however, contain any blanks.  In the default data set, blanks are replaced by underscores (as
in "other_aromatics").  RAOULT terminates the chemical name at the  column where the first number is
found, so all 20 of the spaces allocated for the chemical name do not have to be used. Each line contains
the following data for the chemical:

    a concentration of the chemical in the NAPL in g/cm3,
    n pure compound aqueous solubility of the chemical in mg/L,
    n molecular weight of the chemical (g/mol), and
    n the activity coefficient.

Here the activity coefficients are taken as being equal to 1.0. Each of the data items must be separated
by at least one blank.
[Appendix 6  The RAOULT Utility]              188

-------
Table 106 Default RAOULT.DAT Data Set
9
benzene
toluene
xylenes
1-hexene
eye 1 ohexane
n-hexane
other_aromatics
other paraffins
heavy_ends

0
0
0
0
0
0
0
0
0

.0082
.0426
.0718
.0159
.0021
.0204
.0740
.3367
.1451

1750.
535.
167.
0.
0.
0.
0.
0.
0.

78.
92.
106.
84.
84.
86.
106.
97.2
128.

1.
1.
1.
1.
1.
1.
1.
1.
1.
    The data can also be modified interactively within RAOULT by answering 'Y' to the "Change the input
data ?" prompt.  Table 107 shows the sequence of prompts for changing the benzene solubility from 1750
mg/L to 1780 mg/L and the resulting calculated partition coefficients.
                                             189
[Appendix 6 The RAOULT Utility]

-------
              Table 107 Interactive Modification of the RAOULT Default Data Set
  Change the input data ? (Y or N)
  Y

  Select item to change by number
  1
  Select data item to change
  1   Name
  2   Solubility
     Concentration
     Molecular Weight
     Activity Coefficient
  Enter the new solubility in mg/L
  1780.

  Change another data item? (Y or N)
  N
      Chemical
                    Solubility Cone.
                       (mg/L)   (g/cm3)
     Molecular
     Weight
         Activity
         Coefficient
    1  benzene
    2  toluene
    3  xylenes
    4  1-hexene
    5  cyclohexane
    6  n-hexane
    7  other_aromatics
    8  other_paraffins
    9  heavy_ends
                     1780.0000
                      535.0000
                      167.0000
                          .0000
                          .0000
                          .0000
                          .0000
                          .0000
                          .0000
.0082
.0426
,0718
.0159
.0021
,0204
,0740
.3367
.1451
 78,
 92.
106 ,
 84.
 84,
 86.
106.
 97.
128.
0000
0000
0000
0000
0000
0000
0000
2000
0000
 Change the input data ? (Y or N)
 N

      Hydrocarbon density   =      .7168
      Avg.  Molecular Weight =   104.0458

 Select constituent of interest by number
 1

      Calculated Hydrocarbon/Water Partition Coefficient:
      Composition basis:
        306.4227
      Average molecular weight basis:
        301.8895
  Exit
  Y
? (Y or N)
              successful execution of raoult
1.0000
 .0000
 .0000
 .0000
1.0000
  0000
  0000
  0000
1.0000
[Appendix 6 The RAOULT Utility]
                                190

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Appendix 7  The NTHICK Utility
    A utility program, NTHICK, is provided with HSSM for calculating the averaged LNAPL saturation in
the lens, S0(max), based upon the  theory presented in Appendix 3.3.  NTHICK uses the values from the
HSSM-KO input data set to develop  a relationship between observation well thicknesses, averaged
formation LNAPL  thicknesses and the average  LNAPL saturations.   NTHICK requires  a  number  of
parameters taken from the HSSM-KO input data set. These parameters are listed  in Table 108 and can
be written into the  NTHICK input file manually (Table 109).  Manual data entry,  however, is not necessary
because HSSM-KO automatically creates a file with the extension .NTH that  contains almost all of the
NTHICK input parameters. Only the LNAPL/water interfacial tension, aow, which is not used by HSSM-KO
or HSSM-T, must be added to the .NTH file produced by  HSSM-KO. NTHICK prompts for the value of aow
if it is not found in  the .NTH file, and rewrites the file including the aow value as the 5th line of the *.NTH file.
The program also writes all output to the input data file  (*.NTH). This process does not interfere with later
running of NTHICK with the data set;  any earlier results  are lost, however, when the program is rerun with
a previously used input data file.
Table 108 NTHICK required input data
*.NTH data file line
Line 1
Line 2
Line 3
Line 4
Lines
Parameters
Porosity, TI
Air entry head, hce (m)
Brooks and Corey's A,
Residual water saturation, Swr
Vadose zone residual LNAPL saturation, Sorv
Aquifer residual LNAPL saturation, Sors
Water surface tension, aaw (dyne/cm)
LNAPL surface tension, aao (dyne/cm)
Water density, pw (g/cm3)
LNAPL density, p0 (g/cm3)
LNAPL/water interfacial tension, aow (dyne/cm)
                                            191
[Appendix 7  The NTHICK Utility]

-------
                               Table 109 NTHICK Input Data File
       .4000       0.07      1.500       .10
        .12500      .25
       70.000      30.0000
       1.0000      .7200
      45.0000
    The result of the program is a list of thicknesses and LNAPL saturations.  Table 110 shows a typical
set of output messages from NTHICK. The messages are written both to the screen and to the input data
file as noted above.  First NTHICK echoes the input  data set.  It  follows  with the calculated list of
observation well thicknesses in meters, averaged formation thicknesses in meters and  LNAPL saturations
in the lens.  The lens thicknesses obviously vary with radius and no one value of S0(max) is exactly correct
for the whole lens.

    HSSM requires,  however, a single value of LNAPL  saturation  in the  lens as input.  A procedure for
determining a value of S0(max) is given in the following section.
[Appendix? The NTHICK Utility]               192

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Table 110 Typical NTHICK Output Messages


Estimate of NAPL saturation in OILENS
Porosity
Air entry head
Brooks and Corey lambda
Residual water saturation
Vadose zone residual NAPL
Aquifer residual NAPL sat.
Water surface tension
NAPL surface tension
Water density
NAPL density
.4000
.0700
1.5000
.1000
sat. .1250
.2500
70.0000
30.0000
1.0000
.7200
NAPL/water interfacial tension 45.0000
Observation Averaged
Well Formation
Thickness Thickness
(m) (m)
.1190 .0005
.2690 .0382
.4190 .0877
.5690 .1404
.7190 .1945
.8690 .2495
1.0190 .3049
1.1690 .3607
1.3190 .4167
1.4690 .4729
1.6190 .5292
1.7690 .5856
1.9190 .6421
Exit the program ? (Y or N)
NAPL
Saturation


.0112
.3553
.5230
.6167
.6764
.7177
.7481
.7714
.7898
.8047
.8171
.8276
.8365

* * **
(*)
(m)
(*)
(*)
(*)
(*)
(dyne /cm)
(dyne /cm)
(g/cc)
(g/cc)
(dyne /cm)


















    The "Exit the program ?" prompt at the end of Table 110 either terminates the program by answering
"N," or by answering "Y" continues to the estimation of the NAPL saturation for a specific NAPL formation
thickness.   Table  111  shows the series of NTHICK prompts that occurs when the program  execution
continues.   The user is asked to enter the NAPL thickness in the  formation in meters: here 0.1410 m is
used.  As shown in Appendix 7.1 below, the NAPL formation thickness is obtained from the HSSM model
output. NTHICK responds by echoing the specified average NAPL thickness (.1410) and  calculating the
associated NAPL lens saturation (.3217).
                                            193
[Appendix 7  The NTHICK Utility]

-------
                        Table 111  NAPL Saturation Estimation in NTHICK
  Exit  the program ?  (Y  or N)
  n

  Enter the  average NAPL thickness  in the  formation  (m)
  .1410

   Specified avg.  NAPL thickness in the formation  =       .1410 (m)
   NAPL lens saturation                                =       .3217 (*)
7.1  Procedure for Using NTHICK

    As noted above, the LNAPL lens saturation depends on the thickness of the lens. A procedure for
using NTHICK for determining the lens saturation is given below:

© Develop a data set for HSSM-KO including a trial value of S0(max) and several profile times.

® Run HSSM-KO.

® Edit the *.HSS output file and determine the maximum thickness of the lens.  The maximum thickness
of the lens can  be determined from the lens profiles.  The maximum thickness  of the lens is  read by
subtracting the maximum depth of the top and bottom of the lens (columns 4 and 5 of the first row of data
in Table 112).  The output in this table is from the X2BT.DAT data set described in Section 5.2.

    If this  thickness is  not greater than the difference between columns 2 and 3, then the  lens has not
yet reached its maximum extent  and a later profile time must be  used.  In this case the maximum lens
extent from columns 4 and 5 is 10.0943 m - 9.9533 m = 0.1410 m, which  is greater than the current lens
extent from columns 2 and 3 of 10.0440 m - 9.9729 m = 0.0711  m. Since the maximum lens extent is
greater than the current lens extent, this profile can be used for determining the  lens thickness  and the
thickness 0.1410 m is entered into NTHICK.

® Run NTHICK with the thickness determined from step ®. The  thickness is entered interactively in the
second part of  the NTHICK screen messages (Table 111).   NTHICK calculates  the associated lens
saturation  S0(max).

© Average the  input S0(max) from step © and that from step ®.

© Rerun  HSSM with the S0(max) determined in step ®.

© Repeat until  the S0(max) values are within 0.01.  If this procedure fails to converge within a few trials, a
bisection approach should be used (Forsythe et al., 1977).
[Appendix 7 The NTHICK Utility]               194

-------
Table 112
Lens profile from the *.HSS output file










* RADIAL PROFILE THROUGH OIL LENS
TIME = 200.0000
LENS RADIUS = 10.6437
DEPTH TO WATER TABLE = 10.0000
CURRENT NAPL LENS MAXIMUM EXTENT OF NAPL LENS
RADIUS DEPTH OF DEPTH OF DEPTH OF DEPTH OF
TOP OF LENS LENS BOTTOM TOP OF LENS LENS BOTTOM
(1)

2
2
2
3
3
4
4
5
5
5
6
6
7
7
8
8
8
9
9
10
10
.0000
.0000
.4322
. 8644
.2966
.7287
.1609
.5931
.0253
.4575
.8897
.3218
.7540
.1862
.6184
.0506
.4828
.9149
.3471
.7793
.2115
.6437
(2)
9.9729
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
.9729
. 9739
.9748
.9757
.9764
.9772
.9779
.9785
.9792
.9798
.9804
.9811
.9817
.9823
.9830
.9837
.9844
.9852
.9861
.9873
.9900
CUMULATIVE INFLUX TO LENS


KOPT AND OILENS
TOTAL NAPL MASS

GLOBAL MASS
(3)
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10 .
10.
10.
10.
10.
10.
10.
10.
10.
10.
10 .
1555.
(4)
0440
0440
0413
0390
0368
0348
0330
0312
0295
0278
0262
0246
0229
0213
0197
0180
0162
0143
0123
0099
0069
0000


9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9

(5)
.9533
.9533
.9579
.9617
.9650
.9680
.9704
.9726
.9746
.9762
.9777
.9790
.9802
.9812
.9821
.9830
.9837
.9844
.9852
.9861
.9873
.9900



10.0943
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10

.0943
.0827
.0727
.0642
.0567
.0503
.0446
.0397
.0354
.0315
.0282
.0251
.0226
.0202
.0181
.0162
.0143
.0123
.0099
.0069
.0000

BALANCES
ADDED AT BOUNDARY
NAPL MASS RECOVERED BY MASS

PER CENT ERROR


(KG) 4091.




BALANCE (KG) 4059.

- .7962




195
[Appendix 7  The NTHICK Utility]

-------
7.2  Example NTHICK Calculation Sequence

    Table 113 shows an example sequence of NTHICK and HSSM-KO results which are used to define
the input parameter, S0(max).  Column (a) lists the trial values of S0(max) that were used in the X2BT.DAT data
set.  In the first trial the value was arbitrarily set to 0.5000.  Column (b) gives the maximum NAPL lens
thickness in meters as determined from the X2BT.HSS file as discussed above.  These values were used
in  NTHICK to determine the appropriate value of S0(max) for the lens (column c).  Since the  values in
columns (a) and (c) do not match (0.5000 vs. 0.2253), the appropriate input value was  not used and
another trial is needed. The second trial begins with S0(max) set to the average of the previous values in
columns (a) and (c), that is 0.5 times (0.5000 + 0.2253) = 0.3627. The sequence of running HSSM-KO,
determining the maximum NAPL lens thickness, and estimating the appropriate value of  S0(max) continues
until the values in column (a) and (c) match fairly closely. In this example it took four iterations to find the
correct value of about 0.32  for S0(max).
Table 113 Example sequence of NTHICK and HSSM-KO results
Trial
1
2
3
4
Initial NAPL Saturation
S0(max)
(a)
0.5000
0.3627
0.3288
0.3240
Maximum NAPL lens
thickness
(b)
0.0803
0.1219
0.1393
0.1421
NAPL Saturation from
NTHICK
(c)
0.2253
0.2948
0.3194
0.3231
(Appendix 7 The NTHICK Utility]
196

-------
Appendix 8  The REBUILD  Utility
    Both of the computational modules of HSSM use temporary files for writing output and plot files. Only
at the end of a successful simulation are the temporary files concatenated into output and plot files named
as the user has specified.  If a simulation is interrupted for any reason, the concatenation of the temporary
files will not occur. The user would be left with bits and pieces of the simulation output scattered among
the temporary files.   The REBUILD utility is designed to create the main output files  (name.HSS and
name.TSG) from the temporary files.  It also attempts to create the plot files.  It is not uncommon, however,
that the plot files have incomplete lines or data sets and cannot be plotted. REBUILD does not attempt
to recreate the HSSM-T input data file on the assumption that an interrupted simulation cannot have the
proper mass flux distribution to run HSSM-T.  REBUILD is executed by simply typing

REBUILD

from  DOS or by selecting menu option (3c) "Run REBUILD" from Windows.  REBUILD uses the temporary
files,  if they exist, to gather the correct file names for "rebuilding."  Thus REBUILD is totally automated.
                                            197              [Appendix 8  The REBUILD Utility]

-------
Appendix 9  Dual Installation of the DOS and Windows  Interfaces


    Both interfaces can be installed on the same machine by following these instructions:

© Complete the DOS installation process described in Section 1.7.

© Add the HSSM directory to the path as described in Section 1.7.

© Complete the Windows installation procedure described in Sections 4.3 and 4.3.3. The HSSM directory
should be the same as used for the DOS installation.

The dual installation results in one copy each of HSSM-KO.EXE, HSSM-T.EXE and the other files being copied
to the hard drive. All of the components of the interfaces are found in this one directory. HSSM can then
be run from any DOS directory or from Windows.  DOS and Windows input files can be used with either
interface. Windows, however, places the full directory path for the plot and output file names in the HSSM
input file (see Table 15).  This practice may lead to confusion if the files are later used with the  DOS
interface, because the output and plot files may be placed in a directory other than that occupied by the
input  file.   The confusion  does not arise when  using the Windows interface, because HSSM-WIN
automatically updates the file names to match the current input file's directory.
[Appendix 9  Dual Installation]                  193

-------
Appendix 10   Direct Editing of HSSM-KO Data Files

    Sometimes it is convenient to edit data files directly,  without using HSSM-WIN or PRE-HSSM.
Table 114 shows the items which appear on each line of a valid data file. All data is entered format free;
i.e., no special spacing is required, although at least one space must separate each data item.  In general
an entry is required for each variable given, even for features not used in a particular simulation; therefore,
the use of PRE-HSSM or HSSM-WIN for generating input files is recommended.
Table 114 HSSM-KO Input Data File Structure
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c


*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*



KOPT REQUIRED INPUT DATA
DATA FILES MAY BE PREPARED OR EDITED BY USING THE PREHSSM
PREPROCESSOR

INPUT ARGUMENTS :
IRO READ ONLY INDEX
IWO WRITE ONLY INDEX

OUTPUT ARGUMENTS: NONE

NOTES :
1 . ALL VARIABLE NAMES ARE IN ACCORDANCE WITH FORTRAN NAM-
ING CONVENTIONS --NAMES BEGINNING WITH I THROUGH M ARE
INTEGERS, ALL OTHERS ARE REALS.
2 . ALL INPUT IS FREE -FORMAT


















3 . ZEROS SHOULD BE READ IN FIELDS PERTAINING TO UNUSED VALUES
4 . INPUT DATA UNITS ARE SPECIFIED AS FOLLOWS
(*) DIMENSIONLESS OR NOT APPLICABLE
(M) METERS
(D) DAYS
(C) DEGREES C
(CP) CENTIPOISE 1.0 CP = 0.01 GR/CM/SEC
(M/D) METERS PER DAY
(M2/D) METERS SQUARED PER DAY
(MG/L) MILLIGRAMS PER LITER
(L/KG) LITERS PER KILOGRAM SOIL
(GR/CC) GRAMS PER CUBIC CENTIMETER

LINE 1 PRINT OUTPUT FLAG
IWR OUTPUT WRITING FACTOR
0 SUPPRESS ALL OUTPUT
1 PRODUCE OUTPUT
IREO FOR IWR=1, READ AND ECHO PRINT INPUT DATA ONLY
0 READ AND ECHO PRINT INPUT DATA ONLY
1 RUN MODEL

LINE 2-4 RUN TITLE ( 5A10/ 5A10/ 5A10 )
NT (15) RUN TITLE 3 LINES OF 50 CHARACTERS EACH

LINE 5 . MATRIX PROPERTIES 	
WKS SATURATED VERTICAL HYDRAULIC CONDUCTIVITY (WATER)
RKS RATIO OF HORIZONTAL TO VERTICAL CONDUCTIVITY (
KRF RELATIVE PERMEABILITY MODEL SELECTION INDEX (
1 BURDINE- -BROOKS & COREY MODEL













(*)


(*)




(*)


(M/D)
*)
*)

                                          199            [Appendix 10 HSSM-KO Data Files]

-------
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
if
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*•
*
*
*
*
*
*
*
*
*
*
*
*
*
*
XLAMB
ETA
SWR
LINE 6
WMU
WRHO
IRT

QW/SWMAX
XMKRW
WTABLE

LINE 7
PMU
PRHO
SPR
IAT


PORE SIZE DISTRIBUTION INDEX
FOR KRF = 1, ENTER LAMBDA
POROSITY
RESIDUAL WATER SATURATION
. .WATER PROPERTIES 	
DYNAMIC VISCOSITY OF WATER
DENSITY OF WATER
RAINFALL INPUT TYPE: 1=FLUX SPECIFIED
2=SATURATION SPECIFIED
CONSTANT WATER FLUX OR SATURATION
(*)
(*)
(*)
(CP)
(GR/CC)
(*)
(*)
(M/D) OR (
MAX WATER RELATIVE PERMEABILITY DURING INFILTRATION (*)
DEPTH TO WATER TABLE

..OIL CHARACTERISTICS. ...
DYNAMIC VISCOSITY OF OIL
OIL DENSITY
RESIDUAL (TRAPPED) OIL SATURATION
OIL INPUT TYPE 1=FLUX SPECIFIED
2=VOLUME/AREA SPECIFIED
3=CONSTANT PONDING DEPTH
(M)


(CP)
(GR/CC)
(*)
(*)


4=VARIABLE AFTER CONSTANT PERIOD

LINE 8
HWE
WSIG
OSIG
LINE 9
QP
TPB
TPE
HS

LINE 9
PVOL
DPL

LINE 10 ..
COINI

LINE 11 . .

CAPILLARY SUCTION APPROXIMATION. (ADDITIONAL
AIR ENTRY HEAD
WATER SURFACE TENSION
OIL SURFACE TENSION
. . (FOR IAT-1 AND IAT-3) . . .OIL FLUX 	
OIL FLUX FOR IAT = 1 CASES
OIL EVENT BEGINNING TIME
OIL EVENT ENDING TIME
CONSTANT HEAD FOR IAT=3 CASES

. . ( FOR IAT = 2 ) . . . OIL VOLUME 	
OIL VOLUME/AREA INCORPORATED INTO THE SOIL
LOWER DEPTH OF INITIALLY POLLUTED ZONE

. .DISSOLVED CONSTITUENT 	
INITIAL CONCENTRATION IN OIL (SEE NOTE 5.)

. .DISSOLVED CONSTTTUKNT 	

PARAMETERS )
(M)
(DYNE/CM)
(DYNE/CM)

(M/D)
(D)
(D)
(M)


(M)
(M)


(MG/L)


PARTITIONING COEFFICIENTS:
XXKO
XXKV
XXKS
XXKSH
RHOS

LINE 12 . .
DAIR
DWV
EVAP
TEMP
RH

LINE 13 . .
RADI
RMF
FRING
VDISP
GRAD
OIL/WATER (CO = XXKW*CW)
OIL /AIR (CA = XXKV*CO)
SOLID/WATER (CONSTITUENT)
SOLID/WATER (HYDROCARBON)
BULK DENSITY OF MATRIX

. .VOLATILIZATION MODEL 	
DIFFUSION COEFFICIENT FOR CONSTITUENT IN AIR
DIFFUSION COEFFICIENT FOR WATER VAPOR
WATER EVAPORATION RATE (VOL . /AREA/TIME)
TEMPERATURE
RELATIVE HUMIDITY

. .OILENS SUB-MODEL PARAMETERS (1) 	
SOURCE RADIUS
RADIUS MULTIPLYING FACTOR
HEIGHT OF CAPILLARY FRINGE
VERTICAL DISPERSIVITY OF AQUIFER
GROUNDWATER GRADIENT
(*)
(*)
(L/KG)
(L/KG)
(GR/CC)


(M2/D)
(M2/D)
(M/D)
(C)
(*)


(M)
(*)
(M)
(M2/D)
(*)
[Appendix 10 HSSM-KO Data Files]
200

-------
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
SPRB        TRAPPED OIL SATURATION  BELOW THE WATER TABLE      (*)


LINE 14....OILENS SUB-MODEL PARAMETERS  (2)	
SOLC        WATER SOLUBILITY OF CONSTITUENT                 (MG/L)
SOLH        WATER SOLUBILITY OF HYDROCARBON (OIL)            (MG/L)


LINE 15 .... SIMULATION PARAMETERS	

TM          SIMULATION ENDING TIME    (SEE KSTOP)               (D)
DM          MAXIMUM SOLUTION TIME STEP                         (D)
DTPR        MINIMUM TIME BETWEEN PRINTED TIME STEPS AND       (D)

            MASS BALANCE CHECKS
KSTOP       ENDING CRITERIA                                    (*)
            1   USER SPECIFIED ENDING TIME (TM)
            2   OIL LENS MOTION STOPS
            3   CONSTITUENT MASS FLUX TO  AQUIFER LESS THAN MAXIMUM
            4   CONSTITUENT MASS IN  OIL LENS LESS THAN OPERC*

               MAXIMUM CUMULATIVE INFLUX TO LENS
            (1  IS DEFAULT FOR NO OILENS  SIMULATION OR WHEN OIL
            DOES NOT REACH THE WATER TABLE BEFORE TIME = TM)
OPERC       FACTOR USED WITH KSTOP  =4   (0.0 < OPERC < 1.0)   (*)
LINE 16 ...
NTIMES
LINE 17
PR (NTIMES)

LINE 18 ...
DLONG
DTRAN
PMAX
CMINW
NWELL
LINE 19 . . .
BEGT
ENDT
TINC
TAQU
LINE 20
XWELL ( I )
YWELL ( I )
PROFILES . ... 	
NUMBER OF PROFILES (UP TO 10)

PROFILE TIMES
OMIT LINE 17 IF NTIMES = 0
TSGPLUME INPUT PARAMETERS . . . . ...
AQUIFER LONGITUDINAL DISPERSIVITY
AQUIFER TRANSVERSE DISPERSIVITY
PERCENT OF MAXIMUM CONSTITUENT RADIUS
MIMINUM RECEPTOR WELL CONCENTRATION OF INTEREST
NUMBER OF RECEPTOR WELLS (UP TO 8)
. TSGPLUME INPUT PARAMETERS 2 	
BEGINNING TIME
ENDING TIME
TIME INCREMENT
AQUIFER THICKNESS

X-COORDINATE OF RECEPTOR WELL
Y-COORDINATE OF RECEPTOR WELL

(*)

(D)


(M)
(M)
(*)
(MG/L)
(*)

(D)
(D)
(D)
(M)

(M)
(M)
      *************
                    *****************************************************
                                       201
                                           [Appendix 10  HSSM-KO Data Files]

-------
Appendix 11  Direct Editing of HSSM-T Data Files

    The required parameters for HSSM-T are listed in Table 115. As with HSSM-KO, all input data is
format free. It is recommended to create new HSSM-T input data files by running HSSM-KO.
I

c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c


*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
if
*
*
*
*
*
*
*
*
*
*
*
*
*

*


TSGPLUME

LINE 1
IFILE
LINE 2
OFILE
LINE 3
TFILE
LINE 4
KKSTOP
LINE 5
AL
AT
AV
VEL
FOR
TAQU
LINE 6
R
PMAX
CMIN
ZLAM
LINE 7
BTIME
ETIME
TINTE
LINE 8
NWELL
LINE 9 T
XX
XY
LINE 9 +
TI
RC
HF
CF

*********
Table 115 HSSM-T Input Data File Structure

INPUT DATA


KOPT/OILENS INPUT DATA FILE (A40)

KOPT/OILENS OUTPUT DATA FILE (A40)

TSGPLUME INPUT DATA FILE (A40)

KOPT/OILENS STOPPING CRITERIA (A40)

LONGITUDINAL DISPERSIVITY (M)
TRANSVERSE DISPERSIVITY (M)
VERTICAL DISPERSIVITY (M)
SEEPAGE VELOCITY (M/D)
POROSITY (*)
AQUIFER THICKNESS (M)

RETARDATION FACTOR (*)
PERCENT MAXIMUM CONTAMINANT RADIUS (*)
MINIMUM OUTPUT CONCENTRATION (MG/L)
AQUIFER DECAY COEFFICIENT (1/D)

BEGINNING TIME (D)
ENDING TIME (D)
TIME INCREMENT (D)

NUMBER OF RECEPTOR WELLS (*}
09+ NWELL- 1
X COORDINATE OF WELL (M)
Y COORDINATE OF WELL (M)
NWELL TO END
TIME (*)
RADIUS OF CONTAMINANT (M)
HYDROCARBON FLUX (KG/D)
CONTAMINANT FLUX (KG/D)

********************************************************
[Appendix 11 HSSM-T Data Files]
202

-------
Appendix 12  PRE-HSSM Input Data Templates

    The following tables are to be used as input data templates for the MS-DOS version of HSSM.  Each
input data screen in PRE-HSSM is represented by a template. These pages are intended as aids for
preparing input data sets.
Simulation Control Switches
Variable
I FACE
IWR
IKOPT
ICONC
ILENS
ITSGP
Description
Interface Flag
Print Flag
KOPT Flag
Concentration Flag
OILENS Flag
TSGPLUME Flag
Value
D





Output File Names
File
*.HSS
*.PL1
*.PL2
*.PL3
*.PMI
*.TSG
*.PMP
Description
HSSM-KO Formatted Output File
HSSM-KO Plot File 1
HSSM-KO Plot File 2
HSSM-KO Plot File 3
HSSM-T Input Data File
HSSM-T Formatted Output File
HSSM-T Plot File
Stem Name

  Run Title
                                      203
[Appendix 12 PRE-HSSM Data Templates]

-------
Matrix Properties
Variable
WKS
RKS
KRF
XLAMB
ETA
SWR
Description
Saturated Hydraulic Conductivity (m/d)
Ratio of Horizontal to Vertical Conductivity
Relative Permeability Selection Index
If KRF = 1 Brooks and Corey's Lambda
If KRF = 2 van Genuchten's n
Porosity
Residual Water Saturation
Value






Hydrologic Properties
Variable
WMU
WRHO
IRT
QW/SWMAX
XMKRW
WTABLE
Description
Dynamic Viscosity of Water (cp)
Density of Water (g/cm3)
Recharge Input type
If IRT = 1 Water Flux (m/d)
If IRT = 2 Water Saturation
Maximum Relative Permeability During Infiltration
Depth to the Water Table (m)
Value






NAPL Phase Properties
Variable
PMU
PHRO
SPR
IAT
Description
NAPL Dynamic Viscosity (cp)
NAPL Density (g/cm3)
Vadose Zone NAPL Trapped Saturation (*)
NAPL Application Type
1=flux specified
2=volume/area specified
3=constant head ponding
4= variable ponding after constant head period
Value




[Appendix 12 PRE-HSSM Data Templates]
204

-------
Capillary Suction Approximation Parameters
Variable
HWE
WSIG
OSIG
Description
If KRF = 1 Brooks and Corey's Air Entry Head (m)
If KRF = 2 van Genuchten's a (1/m)
Surface Tension of Water (dyne/cm)
Surface Tension of NAPL (dyne/cm)
Value



NAPL Flux Boundary Condition (IAT = 1)
Variable
QP
TPB
TPE
Description
NAPL flux (m/d)
NAPL Event Beginning Time (d)
NAPL Event Ending Time (d)
Value



NAPL Volume/Area Boundary Condition (IAT = 2)
Variable
PVOL
DPL
Description
NAPL Volume/Area (m)
Lower Depth of the NAPL Zone (m)
Value


Constant NAPL Head or Variable Head Ponding (IAT = 3, 4)
Variable
TPB
TPE
HS
Description
NAPL Event Beginning Time (d)
NAPL Event Ending Time (d)
Constant Head (m)
Value



Dissolved Constituent Concentration
Variable
COINI
Description
Initial Concentration in NAPL (mg/l)
Value

205
[Appendix 12  PRE-HSSM Data Templates]

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Equilibrium Linear Partition Coefficients
Variable
XXKO
XXKS
XXKSH
RHOS
Description
NAPL/Water
Chemical Consistent Solid/Water (L/Kg)
NAPL Solid/Water (L/Kg)
Bulk Density (g/cm3)
Value




OILENS MODEL PARAMETERS: 1
Variable
RADI
RMF
FRING
VDISP
VEL
SPRB
Description
Radius of the Source (m)
Radius Multiplication Factor (*)
Lens Spreading Parameter (m)
Vertical Dispersivity of Aquifer (m)
Groundwater [Darcy] Velocity (m/d)
Aquifer Trapped NAPL Saturation (*)
Value






OILENS MODEL PARAMETERS: 2
Variable
XMSOL
SOLC
SOLH
Description
Maximum NAPL Saturation in Lens
Constituent Water Solubility (rng/L)
Hydrocarbon (NAPL) Water Solubility (mg/L)
Value



Simulation Parameters
Variable
TM
DM
DTPR
KSTOP
OPERC
Description
Simulation Ending Time (d)
Maximum Solution Time Step (d)
Minimum Time Between Pnnted Time Steps (d)
Ending Criterion
Mass Fraction (KSTOP = 4)
Value





[Appendix 12 PRE-HSSM Data Templates]
206

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Profiles
Variable
NTIMES
Description
Number of Profile Times
Value

Profile Times
Variable
PR(1)
PR(2)
PR(3)
PR(4)
PR(5)
PR(6)
PR(7)
PR(8)
PR(9)
PR(10)
Description
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Profile Time (d)
Value










TSGPLUME Data
Variable
DLONG
DTRANS
PMAX
CMINW
ZLAM
NWELL
Description
Aquifer Longitudinal Dispersivity (m)
Aquifer Transverse Dispersivity (m)
Percent Maximum Contaminant Radius
Minimum Output Concentration (mg/L)
Aquifer Decay Rate Coefficient (1/d)
Number of Receptor Points
Value






207
[Appendix 12  PRE-HSSM Data Templates]

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TSGPLUME Simulation Times
Variable
BEGT
ENDT
TINC
TAQU
Description
Beginning Time (d)
Ending Time (d)
Time Increment (d)
Aquifer Thickness (m)
Value




Receptor Well Locations
Variable
X(1), Y(1)
X(2), Y(2)
X(3), Y(3)
X(4), Y(4)
X(5), Y(5)
X(6), Y(6)
Description
X and Y Coordinates of Receptor 1
X and Y Coordinates of Receptor 2
X and Y Coordinates of Receptor 3
X and Y Coordinates of Receptor 4
X and Y Coordinates of Receptor 5
X and Y Coordinates of Receptor 6
X Value






Y Value






[Appendix 12 PRE-HSSM Data Templates]
208

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Appendix 13  HSSM-WIN Input Data Templates
    The following figures are to be used as input data templates for the MS-Windows interface (HSSM-
WIN).  Each input dialog box in HSSM-WIN is represented by a template. These pages are intended as
aids in preparing input data sets.
   Run Titles:
                                                                            Cancel
    'Printing switches
      Q Create output files
      O Echo print data only
      O Run models
Module switches	
 D Run KOPT
 D Run OILENS
 D Write HSSM-T input file
   "File names'
                             NOTE: These filenames will be used if the data file
                            is saved under a new name with the "SaveAs" option.

                                                    HSSM-KO input file
                                                    HSSM-KO output file
                                                    HSSM-KO plot file 1
                                                    HSSM-KO plot file 2
                                                    HSSM-KO plot file 3
                                                    HSSM-T input file
                                                    HSSM-T output file
                                                    HSSM-T plot file
                                           209
     [Appendix 13 HSSM-WIN Data Templates]

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              HYDROLOGIC PROPERTIES
                                         llydrokxjic Parameter'
     Data file:
                                                                                           OK
   Water dynamic viscosity (cp).
   Water density (g/cm*)	
   Water surf, tension (dyne/cm).
   Maximum krw during infiltration
    •Recharge	
    O Average recharge rate (m/d)
    O Saturation
    "Capillary pressure curve model
    O Brooks and Corey
    O van Genuchten
    Brooks and Corey's lambda
    Air entry head (m)	
    Residual water saturation ...
    van Genuchten's alpha (1 /m)
    van Genuchten's n	
     E3 Enable range checking
Cancel
             POROUS MEDIUM PROPERTIES
     Sat'd vert, hydraulic cond. (m/d)..
     Ratio of horz/vert hyd. cond	
     Porosity	
     Bulk density (g/cm*)	
     Aquifer saturated thickness (m)...
     Depth to water table (m)	
     Capillary thickness parameter (m)
     Groundwater gradient (m/m)	
     Longitudinal dispersivity (m)	
     Transverse dispersivity (m)	
     Vertical dispersivity (m)  	
[Appendix 13  HSSM-WIN Data Templates]
210

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                                 Hydrocarbon Phase Parameters
      HYDROCARBON PHASE PROPERTIES

NAPL density (g/cm*)	
NAPL dynamic viscosity (cp).
Hydrocarbon solubility (mg/L)
Aquifer residual NAPL saturation..
Vadose zone residual NAPL sat'n.
Soil/water partition coeff. (L/kg)..
NAPL surface tension (dyne/cm)..
    DISSOLVED CONSTITUENT PROPERTIES
[H Dissolved constituent exists
Initial constit. cone, in NAPL (mg/L).
NAPL/water partition coefficient.. ..
Soil/water partition coeff. (L/kg)...
Constituent solubility (mg/L)	
CH&>nstit. 14-life in aquifer (d)	
                              Cancel
Data file:

E3 Enable range checking            	


 HYDROCARBON RELEASE	
   OiSpecified flux;
   O Specified volume/area
   O Constant head ponding
   O Variable ponding after const head period

   NAPL flux (m/d). .
   Beginning time (d)
   Ending time (d)
   Ponding depth (m)
   NAPL volume/area (m)
   Lower depth of NAPL zone (m)
                                             211
[Appendix 13 HSSM-WIN Data Templates]

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       SIMULATION CONTROL PARAMETERS
Data file:
 Radius of NAPL lens source (m)...
 Radius multiplication factor	
 Max NAPL saturation in NAPL lens .
 Simulation ending time (d)	
 Maximum solution time step (d)....
 Minimum time between printed time
 steps (d)
 "OILENS Simulation ending criterion	
    O User-specified time
    O NAPL lens spreading stops
    O Max contaminant mass flux into aquifer
    O Contaminant leached from lens
    Fraction of mass remaining
          HSSM-T MODEL PARAMETERS
Percent max. contam't radius (%).
Minimum output conc'n (mg/L).
Beginning time (d)	
Ending time (d)	
Time increment (d)	
1*3 Enable range checking
NAPL LENS PROFILES
Enter time (d) for
each of up to
10 profiles
Number of
profiles
RECEPTOR WELL
LOCATIONS

Enter coordinates
for each of up to
6 wells
   |  Cancel  |
1
2
3
4
5
6
7
8
9
10
                                                                           X(m)
      Y(m)
Number of wells
               LZ3
 [Appendix 13 HSSM-WIN Data Templates]      212
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