United States
Environmental Protection
Agency
Robert S. Kerr
Environmental Research Laboratory
Ada OK 74820
Research and Development
EPA/600/S8-90/039 May 1990
&EPA Project Summary
OASIS: Parameter Estimation
System for Aquifer Restoration
Models-User's Manual
Version 2.0
Charles J. Newell, John F. Haasbeek, toren P. Hopkins, Sarah E. Alder-
Schaller, Hanadi S. Rifai, Philip B. Bedient, and G. Anthony Gorry
OASIS, a decision support system for
ground-water contaminant modeling,
was designed to provide a set of
tools to help scientists and modelers
assess ground-water contamination
problems. OASIS was developed
around BIOPLUME II, a numerical
model that simulates the aerobic
degradation of dissolved
hydrocarbons in ground water. The
system was developed in the
HyperCard* environment and contains
extensive documentation and
onscreen help. Question mark icons
throughout lead the user to further
discussion and definitions, thereby
allowing the system to be fully
operational without the aid of paper
documentation. The information in
OASIS includes documentation, a
hydrogeologic database, two
chemical databases, several simple
hydrogeologic models, and the
BIOPLUME II model with
preprocessors and postprocessors.
The system was developed for use
on Macintosh* personal computers
and now contains over 1600 screens
and 9 megabytes (Mb) of information.
The installation of the software
requires 10 Mb of disk space.
This Project Summary was
developed by EPA's R. S. Kerr
Environmental Research Laboratory,
Ada, OK, to announce key findings of
the research project that Is fully
documented in a separate report of
the same title (see Project Report
ordering information at back).
Introduction
OASIS has been developed for the
EPA by Rice University, through the
National Center for Ground Water
Research. As a decision support system,
OASIS was designed to provide scientists
and modelers with a collection of tools to
help assess and analyze ground-water
contamination problems. New types of
software are being developed for
problems that have traditionally been
difficult to implement using conventional
computer technology. Decision Support
Systems (DSS) help the user to deal with
broad problems that do not have a clearly
defined solution procedure. The use of a
ground-water contaminant transport
model is a semi-structured problem that
requires the scientist to make a series of
decisions related to representation of the
site, application of available data, and
types of simulations to be performed.
HyperCard
OASIS was built using HyperCard, a
software package provided with the Apple
Macintosh. In the HyperCard
environment, each different screen of
information is called a "card," and cards
are collected into groups called "stacks."
The cards within a stack are connected to
each other by "links." These links may
take many forms. For example, a link
may consist of a "button" which sends
the user to a particular card or a "field"
"HyperCard and Macintosh are trademarks of
Apple Computer, Inc,
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which displays data taken from another
card. In HyperCard, fields and buttons
link together cards, stacks, and other files
and programs in the computer. The user
is able to navigate through large amounts
of information using a series of mouse
clicks on active buttons. Thus, instead of
going screen by screen through the
computer (or similarly page by page in a
book), a user is allowed nonsequential
access to information in the system. The
first card in the OASIS system (the
OASIS Home card) contains an Intro
button which gives more information
about HyperCard. The user is also
referred to the HyperCard user's manual
for any additional questions.
OASIS System Contents
The OASIS system consists of
documentation, a hydrogeologic
database, two chemical databases,
several simple hydrogeologic models,
and the BIOPLUME II model with
preprocessors and postprocessors.
Each card in OASIS consists of one
screen of information on a picture
background. Cards are organized into
stacks of related information, with most
cards in a stack having similar
backgrounds. Several different
backgrounds are used in the OASIS
system. These backgrounds include
pictures of tab cards, open books,
notebooks, etc. Text in a card is entered
into a text field. Text fields take many
different forms: rectangular, opaque (on a
white background), shadowed,
transparent (only the text can be seen,
not the field) or scrolling. Buttons connect
information within the OASIS system,
thereby providing links between cards.
Clicking on a button takes the user to
another card within the system or
performs some operation on data entered
in a field. In the OASIS system, there is a
convention for each of the button styles
used.
Notebook
The notebook is a system within
OASIS that allows the user to transfer
information between stacks or from the
support system to the models. For
example, parameter data can be taken
from the chemical or hydrogeologic
stacks and put into the notebook for later
use in the preprocessor.
Portions of the hydrogeologic and
chemical databases also contain a button
called Notebook. Clicking the Notebook
button will automatically enter data from
the card into the notebook and then open
the notebook.
Reference Library
The reference stack contains libraries
of information related to ground water.
Clicking on any of the terms in the
flowchart takes the user to contaminant
information related to that source. The
reference stack also contains information
on source by zone, a glossary of terms,
the Rokey database which provides
discussion of parameters used in ground-
water modeling, and a Remediation
stack. The Remediation stack contains
information on different remediation
techniques for contaminated ground-
water aquifers and also presents
BIOPLUME II simulations, which
demonstrate the importance of well
placement and source term definition.
Hydrogeologic Database
The hydrogeologic database was
developed to take advantage of the many
hydrogeologic investigations that have
been conducted at waste sites but have
not been reported in the technical
literature. An extensive technical survey
of ground-water professionals was
conducted with funding from the
American Petroleum Institute and
assistance from the National Water Well
Association. Data from 400 field sites
across the country were obtained from
ground-water professionals and
incorporated into a database.
The database was structured using the
concept of hydrogeologic settings
developed for the EPA's DRASTIC
system, an aquifer vulnerability index
using hydrogeologic settings. The
database is used by determining the
hydrogeologic setting that best matches
a site or an area of interest. The
hydrogeologic setting is selected by
determining the ground-water region,
aquifer media, and then the setting which
best describes the site in question. The
setting is used to access the database;
the database statistics can then be used
for ground-water modeling or for general
site characterization purposes.
General Chemical Database
The general chemical database
contains 117 chemicals with one card of
information per chemical and was taken
from the ROKEY database. Chemical
information can be accessed in four
ways: by category, by name, by EPA
number, or by CAS number (Chemical
Abstract Service number). The general
chemical database contains a Notebook
button which enters data from the card
into the notebook (for more information
on the notebook see the previous
discussion).
Specific Chemical Database
The specific chemical databas
contains 18 chemicals with 25 cards (
information per chemical. The first car
of the database has buttons which acces
information related to Identificatior
Physical Properties, Fire Hazard Date
Chemical Reactions, and Toxicology
These terms are defined as they an
used to describe the chemicals in thi
database.
Darcy's Law
The Darcy's law stack calculates th<
ground-water velocity in a system when
hydraulic conductivity, gradient, am
porosity are known. The help buttoi
(question mark icon) gives information fo
each of the parameters needed in tht
calculation.
Analytical Models
Currently, only one analytical model is
contained in this stack. ODAST is a one-
dimensional solute transport model thai
considers advection, dispersion, solute
decay, source decay, and adsorption,
Output from the model is provided as a
two-way table of dimensionless
concentration versus time and distance.
The ODAST model is a useful tool for
providing preliminary estimates of solute
transport in a ground-water system.
BIOPLUME II Model
BIOPLUME II is a two-dimensional
computer model that simulates the
transport of dissolved hydrocarbons
under the influence of oxygen-limited
biodegradation. BIOPLUME II also
simulates reaeration and anaerobic
biodegradation as a first-order decay in
hydrocarbon concentrations. The model
is based on the USGS solute transport
two-dimensional code. It computes the
changes in concentration over time due
to advection, dispersion, mixing, and
biodegradation. BIOPLUME II solves the
solute transport equation twice: once for
hydrocarbon and once for oxygen. As a
result, two plumes are computed at every
time step. The model assumes an
instantaneous reaction between oxygen
and hydrocarbon to simulate
biodegradation processes. The two
plumes are combined using the principle
of superposition.
The model is extremely versatile in that
it can be used to simulate natural
biodegradation processes, retarded
plumes, and in-situ biorestoration
schemes. BIOPLUME II allows injection
wells to be specified as oxygen sources^
into a contaminated aquifer, and the
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model can be used to evaluate alternate
Ttethods for aquifer reclamation. A
graphical preprocessor for the
BIOPLUME II model has been developed
to facilitate data entry.
OASIS Example
As an example of the way in which
OASIS can be used as a support tool for
the BIOPLUME II model, consider a
gasoline leak at a service station located
in the western mountain ranges. The
following steps might occur when using
the system.
First, the user might consult one of the
two chemical databases contained in
OASIS. The user could refer to the
specific chemical database to examine
physical data on benzene (Figure 1). If
the user is unfamiliar with the
hydrogeology of the area, he or she can
enter the hydrogeologic database. The
correct ground water region is selected
first, then the aquifer media, and then the
hydrogeologic setting, as pictured in
Figure 2. Once the setting is known, the
user can examine data from sites with a
similar hydrogeologic setting. The
hydrogeologic data is designed to be
used as a general educational tool and
not as a substitute for field work.
At this point, the user can run the
inalytical model to help set up the
problem or enter directly into the
BIOPLUME II preprocessor. The
preprocessor was designed to do three
things: structure the data entry process,
give immediate* access to ground water
and data entry help, and provide a
graphical method for entering and
viewing the spatial information used by
the model.
Once the user finishes entering the
data, the preprocessor makes a text file
corresponding to the format required by
BIOPLUME II. The model is run and the
graphical postprocessor, BioGraph,
displays the output from the model
(contaminant concentrations over the
area of the aquifer) in the form of
patterns. Darker patterns correspond to
higher concentrations. The development^
of the plume over time can be seen witlf
an animation option in BioGraph.
Concentration profiles over time or over
distance can be examined also. The
preprocessor and the postprocessor for
BIOPLUME II were designed to facilitate
model calibration and data evaluation.
Physical data
Physic*! State
Melting Point
Boiling Point
Specific Gravity
Tapor Pressure
Vapor Density
Solubility in Water
Solubility in Coa*on
Organic Solvents
Fire Hazard Data
liquid
3.3 - 6"C
80°C
0.88
73-76 MM Kg «t 20°C
2.7 - 2.8
0.07 - 0 19 wt *
•»lc,CS2,»th,»c »,
a.ce,CHC13,and CC14
Benzene
2,3,6,7,206
1,2,3,4,206
2,3,4,6,8,206
1,14,200,206
6,8,10,14,200
3,186,187,203,206,210,226
2,4,6,7
Flash Point - Open Cup 21 *t
Closed Cup 12°F
Autoignition Temperature 1000T - 1076'F
Flawaability Units in Air (* by vol)
Lover 1 3
14
3,3,6,8,10,48,206
3,5,6,7,8,10,13,206
8,13,14,207
T
2
ID info
Properties ss
Reactions H| Toxicology
Modeling
I References I
Figure 1. Card from the specific chemical database, benzene.
Setting: GLACIATED MOUNTAIN
VALLEYS
This jetting is characterized by moderate
topographic relief and very coarse grimed
deposits associated with the near mountain
glacial features such as cirques and paternoster
lakes. These deposits may serve as localized
sources of water. Water tables ere typically
shallow with coarse grained deposits present at
the surface. Mountain glaciers may be present
in some areas. Although precipitation may not be
great, recharge is relatively high when
compared to other settings in the region because
of the large volumes of water produced from the
glaciers during the summer melting cycle. These
I recent glacial deposits are underlain by
I fractured bedrock.
Figure 2. Hydrogeolog/c setting card.
O Show Key
O Show Typical Characteristics
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C. J. Newell, J. F. Haasbeek, L P. Hopkins, S. E. Alder-Schaller, H. S. Rifai, P.
B. Bedient, and G. A. Gorry. are with the Department of Environmental Science
and Engineering, Rice Univcersity, Houston, TX 77251-1892.
Joe R. Williams is the EPA Project Officer (see below).
The complete report, entitled "OASIS: Parameter Estimation System for Aquifer
Restoration Models, User's Manual Version 2.0," (Order No. PB 90-181-
314AS; Cost: $17.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
R. S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK 74820
US.OFFICIAL MAIL'
United States
Environmental Protection
Agency
Center tor Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S8-90/039
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