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Resource Library > Technology Transfer > Programs and Initiatives > Source Zone Treatment > Software

Source Zones - Software
Numerous computer programs ("software packages") that can be used to assist in the evaluation of NAPL sites, and in planning, designing, and monitoring the performance of remedial measures for soil, groundwater, and soil vapor affected by NAPL contaminants, are in the public domain, or are available commercially.  Software packages that may be of use in assessing and remediating NAPL sites fall into three general categories:

Visualization software can be used to assist in evaluating and displaying the distribution of NAPL and dissolved contaminants in the subsurface at a site.

Simulation software is used to represent the actual physical and chemical conditions at a site, as a means of organizing site-related information, understanding the processes that are occurring, and making predictions about the movement and fate of site-related contaminants in the environment.

Decision Support System (DSS) software combines environmental data analysis tools and simulation models into a framework for managing and presenting information about a site, to assist and guide environmental decision makers in making site characterization, monitoring, and cleanup decisions (e.g., where to sample; cost/benefit analysis of additional or reduced sampling; remedy selection).  An effective DSS package can be used to integrate, analyze, and present environmental information to assist a project manager in developing a cost-effective and defensible, cleanup/monitoring strategy.

Some of the currently-available software packages are described briefly in the following subsections.  Contact information for the software developer or vendor also is provided.  This brief review is not intended to be an endorsement of any particular software.  As a matter of policy, the US Air Force does not endorse commercial products.  Selection of a particular code for a site-specific application depends on many technical (site and contaminant characteristics), regulatory (compliance agreements, schedules, and acceptance of a particular choice of software), and economic (cost of software and degree of training required) factors.  These factors and the capabilities of the software will influence the selection of a particular software package as a tool for use in site evaluation, in identifying potential remedies, and in the decision making process generally.

Visualization Software
Effective visualization software will integrate interpolation tools, statistical and geostatistical analyses, and fully three-dimensional (3-D) visualization tools into a system that can adontaminants, and regions containing contaminants above specified threshold condress, among other things, sample optimization and cost-benefit analysis, by generating 3-D maps displaying subsurface features, the distribution of ccentrations at a specified level of statistical probability.  Some visualization software also can be used to perform geostatistical analyses that will optimize sampling locations for site characterization, to estimate volumes and mass of contaminated media for use in cost-benefit analyses (i.e., generating estimates of volume requiring remediation as a function of required cleanup level), or to quantify the statistical variation in the contaminant volume and mass estimates resulting from the characterization information available.  In addition to generating the required information and output, the ideal visualization software package also will be reliable, require only modest investment in financial and computational resources, have a broad range of applicability, and be easy to operate.

Several visualization software packages have been evaluated by the US Environmental Protection Agency (USEPA), in conjuction with USEPA's Environmental Technology Verification Program.  The results of USEPA's evaluation can be reviewed on the World-Wide Web at http://www.epa.gov/etv/verifications/vcenter1-1.html  The features of several of these, and of other currently-available commercial and public-domain visualization software packages, are described briefly in this subsection.  Click on the appropriate link in the following table to view a description of the selected visualization software.

Visualization Software Reviewed on this Page
Visualization Software Package Ease of Usea/ Availabilityb/ Applications
3D Analyst™ M C Spatial analysis extensions to ArcView™ geographic information system
EarthVision ® E C Geospatial modeling, analysis and visualization suite
EVS™ M C True 3-D volumetric modeling, analysis, and visualization capabilities
EWB M C Suite of integrated applications for analysis and visualization of large environmental data sets
GMS D C Comprehensive graphical environment that can be used for data organization and visualization, constructing groundwater models, and performing groundwater simulations
Rockworks M C Integrated geological data management, analysis, and visualization tool
SADA E P DSS package that provides visualization tools which are simple to use, easy to understand, and facilitate data exploration, modeling, and decision analysis
Tecplot M C Applicable to a wide variety of graphical applications, ranging from production of 2-D scatter plots to contouring of spatial data and 3-D visualization

a/ E  =  easy; M  =  moderately difficult; D  =  difficult.
b/  P  =  public domain; C  =  commercial.

3D ANALYST™/Spatial Analyst™
3D Analyst™ and Spatial Analyst™ are extensions (special-purpose "tools") to ArcView™, a geographic information system (GIS), capable of assisting environmental professionals in quickly and comprehensively characterizing, managing, and visualizing information relevant to understanding environmental contamination problems.  The ArcView™ GIS integrates common database operations, such as query and statistical analysis, with the visualization and geographic analysis benefits offered by maps.  The Spatial Analyst™ extension to ArcView™ was developed to solve problems requiring that distance or other continuous surface modeling information be considered as part of the analysis.  The 3D Analyst™ extension permits the creation of three-dimensional surface models and assists users with three primary tasks -- surface model construction, data analysis, and graphic display of data.

ArcView™ can be used to map physical site features, including wells and buildings, and to generate maps of any type of surface, including hydraulic potential ("head"), ground-surface elevations, bedrock elevations, and contaminant concentrations.  Data provided on the maps can range from posting of a marker at each data location to generation of contours.

ArcGIS 3D Analyst™ enhances the capabilities of ArcView by providing a suite of methods for interactive perspective viewing and advanced tools for three-dimensional modeling and analysis applications.  ArcGIS 3D Analyst™ is integrated into the ArcGIS Desktop to allow the user to create dynamic and interactive maps, thereby enabling users to effectively visualize and analyze surface data.  Using 3D Analyst™, the user can view a surface from multiple viewpoints, query a surface, determine what is visible from a chosen location on a surface, and create a realistic perspective image by draping raster and vector data over a surface.

The ArcView™ platform has a graphical user interface with a logical menu structure to enhance the ease of use of the options in the software package.  ArcView™ supports data queries that permit evaluation of the data based on user-defined criteria.  This query capability is a powerful data analysis tool.  ArcView™ accepts a wide range of formats when importing data (e.g., database files, drawing files in .shp and .jpg formats) and can export files using a large number of formats.  The basic features in ArcView™ are easy to use, to the extent that an analyst with a background in environmental remediation and a basic knowledge of database and GIS operations can use ArcView™ after one to two days of training.

ArcView™ and the 3D Analyst™ and Spatial Analyst™ extensions were developed by the Environmental Systems Research Institute (ESRI), and are available for purchase from ESRI on the World-Wide Web: ESRI homepage

Earthvision®
EarthVision® provides geospatial modeling, analysis and visualization capabilities, which can be used in analyzing the geometries and relationships of features in the earth's surface, subsurface, atmosphere and oceans; and for modeling the distribution of physical properties therein.  Users can develop representational models (i.e., surfaces, volumes, and geologic structures) from spatial data.  These models can be integrated with other types of data, such as site plans, aerial photographs, which then can be viewed and manipulated interactively.  In addition to generating traditional mapping products such as base maps and contour maps, cross-sections, and fence and block diagrams, users also can create shaded, three-dimensional (3-D) graphics, because image draping and 3-D viewing are part of the basic system.  Extensions to the basic EarthVision® software also can be used to generate structure maps based on integrated 3-D models.

EarthVision® can import spatial data in a number of different formats.  The easy-to-learn interface and advanced capabilities allow even inexperienced users to build expert models quickly and easily.

EarthVision® was developed by Dynamic Graphics, and is available for purchase from Dynamic Graphics on the World-Wide Web:

Dynamic Graphics homepage

Environmental Visualization System (EVS™)
Environmental Visualization System (EVS™) software combines state-of-the-art analysis and visualization tools into extremely powerful software systems, developed to meet the needs of geologists, geochemists, environmental engineers, and modelers.  EVS™ provides true 3-D volumetric modeling, analysis, and visualization to assist in identifying patterns and trends in geologic, hydrologic, and environmental data.  The more advanced versions of the software allow these capabilities to be customized and combined to satisfy the analysis and visualization needs of any application.  Advanced capabilities include a number of gridding options, model building, output options, geostatistics, GIS functions, high-level animation generation and support, real-time terrain fly-over, advanced geologic modeling, interactive fence-diagrams, and much more.  The tools included in EVS™ are capable of reducing costs associated with site assessment, and can enhance an environmental manager's capability of analyzing and presenting data for site assessments, financial and remediation planning, litigation support, regulatory reporting, and public relations.

Block diagram showing contaminant plume, constructed using EVS
Block diagram showing contaminant plume, constructed using EVS™

EVS™ was developed by C Tech and is available for purchase from C Tech's site on the World-Wide Web:

C Tech homepage

Environmental Workbench (EWB)
The Environmental WorkBench (EWB) is a suite of integrated applications designed for the analysis and visualization of large environmental data sets.  (Note: Autometric sells EWB as part of its EDGE product, Waterloo Hydrogeologic sells EWB under the name Visual Groundwater, and EarthWatch Communications sells EWB as Forecast 2000.)  EWB is a 3-D visualization software package that can be used to deliver high-quality, three-dimensional presentations of subsurface characterization data and groundwater modeling results.  Site investigation data, including geologic, hydrologic, and chemical data, can be stored in an electronic database, and used to create 3-D data sets for graphic display.  The advanced visualization tools provide interactive visualization capabilities for displaying, manipulating, and rotating multiple three-dimensional data sets, including:

  • Environmental sampling data such as stratigraphy, groundwater potentiometric elevations, and chemical data for soil and groundwater,
  • Contaminant transport modeling results, and
  • 3-D iso-concentration plumes for multiple contaminant species.
After a 3-D model has been created, multiple slices through the model can be generated along any orientation for viewing geological cross-sections, groundwater elevations, groundwater plumes and/or soil contamination zones, and volumes of contaminated soil or groundwater can be calculated.

EWB was developed by the Software Solutions and Environmental Service Company (SSESCO), and is available for purchase from SSESCO's site on the World-Wide Web:

SSESCO homepage

Groundwater Modeling System (GMS)
The Department of Defense Groundwater Modeling System (GMS) is a comprehensive graphical environment that can be used for data organization and visualization, constructing groundwater models, and performing groundwater simulations.  The complete GMS system consists of a graphical user interface (the GMS program) and a number of analysis codes that originated with other authors or organizations.  Tools are provided for site characterization, model conceptualization, mesh and grid generation, geostatistics, and post-processing.  GMS is completely graphical, and can display spatial data in plan view or 3-D oblique view, or as a block model that can be rotated interactively.  Cross-sections and fence diagrams may be cut anywhere in the model.  Hidden surface removal, and color and light source shading can be used to generate highly photo-realistic rendered images.  Contours, color fringes, and 3-D iso-surfaces can be used to display the variation of input data or computed results.  In addition, the system is completely modular, and the various modules can be combined to present subsurface data graphically (visualization modules), construct and run simulations of groundwater flow and contaminant migration (simulation modules), and present the results of simulations (predictive modules).  The GMS software package is intended primarily for use in constructing and applying groundwater models, and consequently is described in greater detail on the Simulation Software page.  Those modules used primarily for data evaluation, presentation, and visualization are described below.

The Subsurface Characterization Module is used to construct triangulated irregular networks (TINs) and solid models, and to display borehole data.  TINs are formed by connecting a set of points (either scattered, gridded, or from boreholes) with edges to form a network of triangles.  TINs can be used to represent the surface of a geologic unit, and can be displayed in oblique view with hidden surfaces removed.  Solid models of stratigraphy also can be constructed, allowing cross-sections to be cut anywhere on the model.

Contamination Plume
The Borehole Module is used to display borehole data.  Borehole data can be imported from a text file or entered via a spreadsheet-like dialog.  Once the boreholes are in memory they can be displayed in a 3-D oblique view with depth perspective and colors to represent the different zones encountered by the borehole.  Contacts or regions on the boreholes can be selected interactively and used in the construction of TINs, solid models, and 3-D finite element meshes.  Continuously sampled data resulting from cone penetrometer or geophysical surveys can also be imported to the Borehole Module.  The sample data can be plotted in 3-D, converted to scatter points for interpolation, or used to infer stratigraphy.

The Solid Module is used to construct three-dimensional models of stratigraphy using boundary representation solid models.  Once such a model is created, cross sections can be cut anywhere on the model, hidden surfaces can be removed, and shading can be used to generate realistic images.  With the current version of GMS, solids are used primarily for site characterization and visualization. In future versions, solids also will be used to aid in the automatic generation of 3D finite element meshes.

GMS is available for purchase from several vendors.  General information and purchase pricing can be obtained at the following sites on the World-Wide Web:


ROCKWORKS

RockWorks2002™ is an integrated geological data management, analysis, and visualization tool.  RockWorks2002™ includes two sets of tools:

  • Borehole-data based utilities, and
  • General geological utilities.
Utilities applied to borehole data can be used to create boring logs, cross sections, fence diagrams, solid models (contaminant plume, orebody, petroleum reservoir), stratigraphic layer models and surfaces, volumetric calculations, contour maps and terrain models.  The geologic utilities include hydrological and hydrochemical tools (for drawdown calculations, and generating Piper and Stiff diagrams), directional statistics/structural geology tools (rose and stereonet diagrams, lineation maps and densities), simple univariate statistics and diagrams (histograms, scatterplots), ternary diagrams, surveying and mapping tools, and simple coordinate conversions.

Rockworks2002™ was developed by Rockware and is available for purchase from Rockware on the World-Wide Web:

incorporate hand-drawn sections into rockworks 3-D diagrams
Rockware homepage

Spatial Analysis and Decision Assitance (SADA)
The Spatial Analysis and Decision Assistance (SADA) software package which integrates tools from several environmental assessment fields, including visualization, geospatial analysis, statistical analysis, human-health risk assessment, ecological risk assessment, cost/benefit analysis, sampling design, and decision analysis, into an effective problem-solving environment.  These tools can be used independently or collectively to address site specific concerns when characterizing a contaminated site, assessing risk, determining the location of future sampling, and during the design of  remedial measures.  The SADA software package was developed primarily for use as a DSS, and consequently is described in greater detail on the Decision Support Software page.  Those modules used primarily for data evaluation, presentation, and visualization are described below.

The visualization tools implemented in SADA are simple to use, easy to understand, and facilitate data exploration, modeling, and decision analysis.  SADA provides a number of methods for the exploration of environmental data that can be categorized by depth during remedial investigations (generally soil-sampling data and groundwater sampling and elevation data).  Data exploration tools include two- and three-dimensional data visualization options.  Two-dimensional information is presented as simple coordinate plots.  Three-dimensional information can be presented as two-dimensional (2-D) slices (layers) or as a 3-D model.  In the layer approach, the user can easily set the depth of each of the layers in order to quickly display results. The 3-D volumetric modeling approach allows display of data at all depths at once.  The volumetric-modeling view can be customized with a variety of features that allow the user to better characterize contaminant distribution with depth.

In order to allow presentation of environmental data which may be spatially associated with other site features or characteristics, SADA can accept map layers from a GIS saved in Data eXchange Format (DXF). Multiple layers can be imported into SADA, and the user can control the order and coloring schemes of the various layers.  In addition, the user can select a sub-region of the site to direct the geospatial and risk analyses.  This user-defined polygon will only consider data points within the interior of the delimited region when performing spatial analyses.

SADA is public-domain software that was developed, and is maintained by The Institute for Environmental Modeling at the University of Tennessee, on behalf of the USEPA and the US Nuclear Regulatory Commission (NRC).  A detailed online help system is supplied with the software package, and provides examples of how to apply the visualization tools.  Technical support is available through e-mail.  A fully-functional freeware version is available on the World-Wide Web:

The Institute for Environmental Modeling

Tecplot
The Tecplot™ software package can be used for a wide variety of graphical applications, ranging from production of 2-D scatter plots to contouring of spatial data and 3-D visualization.  Data to be processed in Tecplot are conveniently displayed and edited in a spreadsheet format.  Tecplot uses an intuitive menu-driven graphical user interface to create and arrange plots, with no command-line entry or programming required.  Primary plotting tools and settings are conveniently located on the sidebar.  Up to 128 plots can be placed on a single page, with each plot contained in an adjustable frame which can be moved and resized interactively.  Best-fit lines or surfaces can be fitted to the plotted data using least-squares methods, to generate linear, polynomial, power, or exponential curves.

Orthographic and perspective projections of spatial data can be generated in # dimensions.  On 2-D and 3-D surfaces, contour lines can be displayed, added, and deleted interactively, and contours can be labeled automatically or manually.  Color flood can be specified between contour levels, and color fills can be selected.  Three-dimensional models can be sliced interactively in any direction to display a mesh, contours, or vectors on one, or multiple slice planes.  Sets of points or polylines to which 2-D and 3-D surface data are to be interpolated can be specified interactively and extracted for display as a separate plot.  Blocks of 3-D volumes can be cut away to reveal internal structure.

Tecplot™ was developed by AMTEC and is available for purchase from AMTEC on the World-Wide Web:

AMTEC homepage

Simulation Software
Numerous software packages are available which can be used to simulate the functioning of parts of the physical world, using mathematical methods.  These simulation packages, generically known as "models", are tools designed to represent a simplified version of reality (Wang and Anderson, 1982).  For example, a mathematical model of groundwater flow consists of a set of differential equations that describes the movement of water through a porous medium.  A mathematical model of contaminant migration consists of a set of differential equations that describes the movement of a dissolved constituent in groundwater.  If properly constructed, a model can be a valuable predictive tool - for use, for example, in evaluating the degree to which continued migration of contaminants to potential exposure points could cause an excess risk to a potential receptor.

Of course, the validity of predictions made using a model depends on how well the model describes (or "approximates") conditions in the real world.  Any model designed to represent in a realistic way the movement of groundwater and dissolved constituents at a particular site must account for the site-specific physical, hydraulic, and chemical conditions in the subsurface in the area ( Luckner and Schestakow, 1991).  Mechanisms and timing of contaminant release also must be simulated appropriately, and in general, the mass of a particular constituent that originally was introduced to the subsurface also must be known or estimated (Spitz and Moreno, 1996).

A particular advantage of simulation software is that after a model has been constructed to represent that part of the subsurface system under investigation, it can be used to evaluate the possible range in performance of one or more potential remedies.  Models thus can be of particular utility in the selection, design, and evaluation of remedial measures applied to NAPL source zones.

Effective simulation software can be used to organize site-related information, to generate a realistic representation of the subsurface system(s) under consideration and the processes that are occurring, and to make defensible predictions about the movement and fate of site-related contaminants in the environment at that location.  The most generally useful simulation software also can be used to design and evaluate the likely range in performance of one or more remedial measures.  In addition to generating the required representations and output, the ideal simulation software package also will be reliable, require only modest investment in financial and computational resources, have a broad range of applicability, and be easy to operate.  Unfortunately, many currently-available simulation software packages are proprietary, and commercial licenses can be expensive.  Furthermore, as a general rule, simulation software is best applied by a knowledgable user, familiar with modeling concepts, and with the characteristics, requirements, advantages, and limitations of the particular software package being used.

Several well-known simulation software packages have been developed on behalf of, or are maintained by the USEPA, in conjuction with USEPA's Center for Subsurface Modeling Software (CSMoS), located on the World-Wide Web at http://www.epa.gov/ada/csmos/index.html  The features of several of these, and of other currently-available commercial and public-domain simulation software packages, are described briefly in this subsection.  Click on the appropriate link in the following table to view a description of the selected simulation software. 

Simulation Software Packages Reviewed on this Page
Simulation Software Package Ease of Use a/ Availabilityb/ Applications
API-LNAST E P Performs linked LNAPL dissolution, volatilization, and solute transport calculations
HSSM E P Simulates subsurface releases of LNAPLs in homogeneous soils
NAPL Simulator E P Simulates the contamination of soils and groundwater resulting from NAPL releases
RITZ M P Simulates movement of groundwater in the unsaturated zone coupled with transport of oily wastes
AIRFLOW/SVE M C Simulates response of 3-phase system to soil-vapor extraction
API-FPR M P Spreadsheet models for evaluating the recovery of free-product LNAPL
BIOSLURP M C Simulates multicomponent transport in groundwater and in the unsaturated-zone vapor phase, for use in the design and evaluation of bioslurping systems.
BioSVE M C Simulates effects of SVE, bioventing, and biodegradation in a single screening model
Hyperventilate M C Evaluates feasibility of using soil-vapor extraction at a site
BIOPLUME III M P Simulates natural attenuation of organic contaminants in groundwater
GMS D C Comprehensive graphical environment that can be used for data organization and visualization, constructing groundwater models, and performing groundwater simulations
MOTRANS M C Simulates movement of water, dense or light NAPL, and air, in 2-D vertical sections through saturated and unsaturated zones
SWANFLOW D P Simulates movement of water and NAPL in 3-D under saturated and unsaturated near-surface conditions
a/  E  =  easy; M  =  moderately difficult; D  =  difficult.
b/  P  =  public domain; C = commercial.
API-LNAST
The American Petroleum Institute's (API) LNAPL dissolution and transport screening tool (LNAST) is a software utility that is applied primarily an organizational tool to aid the user in performing linked dissolution, volatilization, and solute transport calculations.  Because the software is based on several linked methods (or "tools,") the term "toolkit" is used to refer to the API-LNAST software.  This toolkit is intended to help the user distinguish, in a site-specific context, between effective and ineffective remediation using reductions in concentrations and associated risk as a consistent benchmark.

The LNAST software utility calculates (1) the depletion of soluble or volatile components from a multicomponent LNAPL source area, followed by (2) the downgradient movement of a dissolved phase, subject to biodegradation and dispersion.  The following sequence of calculations is completed during the application of the program:

1.         The user selects the appropriate, site-specific physical and chemical properties of soil, groundwater, and LNAPL.  This is done through a series of five input tabs in the LNAPL utility.

2.         The user directs the program to calculate the depletion of the LNAPL source through the mechanisms of dissolution and/or volatilization.  Based on the data previously input, the software utility first calculates LNAPL mass, distribution, and the fractions of LNAPL constituents of concern.  Multiphase fluid mechanics then are used to calculate the groundwater movement through the LNAPL zone, and chemical transport principles are linked to estimate advective and dispersive chemical losses from the LNAPL source.  This series of calculations generates the dissolved-phase concentration of each of the specified LNAPL components in the source area (i.e., in contact with the LNAPL) as a function of time.  These results may be displayed, printed, or copied as a table of values, a graph, or both.

3.         The results of the LNAPL source-depletion calculation are used to calculate the resulting downgradient dissolved phase concentrations for each of the soluble components using an analytic solution to the three-dimensional solute transport equation under steady-state groundwater flow conditions.  The output from the source area depletion calculations are used as input to the downgradient dissolved phase calculations.  The results of calculations of the downgradient dissolved-phase concentrations may be displayed, printed, or copied as a table of values, a graph, or both.

API-LNAST is public-domain software that was developed, and is maintained by Aqui-Ver, Inc.  A manual is supplied with the software package, and provides examples of how to apply the toolkit.  Technical support is available through e-mail.  A fully-functional freeware version is available at the Aqui-Ver, Inc. site on the World-Wide Web:

AQUI-Ver, Inc.

Hydrocarbon Spill Screening Model (HSSM)
The Hydrocarbon Spill Screening Model (HSSM) is intended for simulation of subsurface releases of light nonaqueous phase liquids (LNAPLs) in homogeneous soils.  The model consists of separate modules to address LNAPL flow through the vadose zone, LNAPL spreading in the capillary fringe, and dissolved transport of chemical constituents of the LNAPL in an aquifer.  These modules are based on simplified conceptualizations of flow and transport phenomena, so that the resulting model is a practical, though approximate tool.

Spreading in the capillary fringe is assumed to be radial, and is not affected by regional water-table gradients.  Simulation of advective-dispersive transport of dissolved phase in the saturated zone is assumed to be uniform ("steady-state flow").  The LNAPL source is assumed to originate at land surface, and may be a constant flux source, a specified volume source, or a constant head source.  Graphic output includes saturation profiles, contaminant mass balance calculated for the NAPL lens, and concentration histories at potential receptor locations.  HSSM includes a soil property regression utility to estimate soil hydraulic properties, also includes a utility for calculation of the NAPL/water partition coefficient based on Raoult's law.

A manual is supplied, to provide guidance in selecting parameter values, and several utility programs are provided to calculate model parameters.  Example problems also are provided, to demonstrate how values for each parameter of the model should be selected.  HSSM was developed by the University of Texas at Austin on behalf of the USEPA, and is maintained by the USEPA's Center for Subsurface Modeling Support (CSMoS).  It can be obtained free of charge from the CSMoS page on the World-Wide Web:

CSMoS

An enhanced, proprietary version of the HSSM software is available for purchase from the International Groundwater Modeling Center's (IGWMC) site on the World-Wide Web:

IGWMC homepage

NAPL Simulator
NAPL Simulator is used to simulate the contamination of soils and aquifers which results from the release of NAPL organic liquids.  The simulator can be used to model a vadose zone which is in contact with the atmosphere, a capillary zone, and a water-table aquifer zone.  Three mobile phases are accommodated: water, NAPL, and vapor.  NAPL dissolution and volatilization are accounted for through rate-limited mass transfer sub-models.

Three fundamental, interrelated physical processes are addressed in the NAPL Simulator - multiphase flow, interphase transfer, and constituent mass transport.  Simulation of multiphase flow defines the time-dependent extent of the mobile and immobile components of water, NAPL, and vapor phases.  Simulation of interphase mass transfer defines how NAPL constituents partition between phases.  Simulation of constituent mass transport defines the temporal and spatial distribution of NAPL contaminants in each phase.

The NAPL Simulator model was developed to enable these three processes to be quantified, and has the following capabilities:

  • Fluid entrapment and release can be simulated,
  • Rate-limited mass transfer is used to describe NAPL dissolution and volatilization, and
  • Advective-dispersive transport is simulated in the dissolved and vapor phases.
The model is coupled with dedicated pre-processing and post-processing software, to simply data input and enhance the interpretation and visualization of model output, forming an effective tool for use in simulation and analyses of field-scale NAPL releases.

The public-domain NAPL Simulator package was developed by the Research Center for Groundwater Remediation Design at the Univeristy of Vermont on behalf of the USEPA, and is maintained by the USEPA's CSMoS.  It can be obtained free of charge from the CSMoS page on the World-Wide Web:

CSMoS
Regulatory and Investigative Treatment Zone (RITZ)
Regulatory and Investigative Treatment Zone (RITZ) is a screening-level model for simulation of the movement of groundwater in the unsaturated zone coupled with transport of oily wastes, and was developed to assist decision makers in systematically evaluating the movement and fate of hazardous chemicals during land treatment of oily wastes.  The model considers the downward movement of a pollutant in water percolating through soil in the unsaturated zone, volatilization of the pollutant and subsequent loss to the atmosphere, and degradation.  The model also examines the influence of the oil phase on the movement and fate of the pollutant.  The analytical model is based on the assumptions that waste material is uniformly mixed with soil at land surface, that the oil in the waste material is immobile, and that soil properties are uniform from land surface to the base of the treatment zone.  The flux of water through the unsaturated zone is considered to be uniform across the site and through time, the partitioning of pollutant among the sorbed, dissolved, vapor, and oil phases is described by linear equilibrium isotherms, and the degradation of pollutant and oil is considered to be a first-order process.

RITZ is menu-driven to facilitate interactive data entry, and generates output in graphical and tabular format.  The documentation includes installation instructions and a user's manual developed by the USEPA.  RITZ was developed by the Oklahoma State University on behalf of the USEPA, and is maintained by the USEPA's CSMoS.  It can be obtained free of charge from the CSMoS page on the World-Wide Web:

CSMoS

An enhanced, proprietary version of the HSSM software is available for purchase from the IGWMC site on the World-Wide Web:

IGWMC homepage

AIRFLOW/SVE
AIRFLOW/SVE is a numerical model that can be used for simulation of the response of three-phase (NAPL, vapor, and dissolved phases) multi-component systems (complex chemical mixtures such as petroleum fuels) to soil-vapor extraction (SVE) in areas contaminated by NAPLs.  The model accounts for radial-symmetric steady-state vapor flow towards an extraction well, and transient, spatially-variable vapor transport of multiple species in heterogeneous unsaturated media.  Simulated NAPL can be present in the form of residual, lenses or pools, and can be distributed in spatially-variable configurations.  Mass transfer between NAPL, dissolved, and vapor phases can be represented as kinetically-controlled, or as equilibrium-process controlled.  Various types of sorption isotherms can be considered.  Differential NAPL depletion also is simulated, with the more volatile compounds being depleted first, leaving behind the less volatile species. The model results can be displayed as isobar contours, velocity vectors, pathlines, or concentration contours for each component and mass remaining contours. Model output also can be presented in other ways, including total mass removed by the well through time, and breakthrough curves for each component.

AIRFLOW/SVE is a self-contained package, in that all data input and output is done via an interactive graphical user interface.  The user-friendly interface makes the design and modification of highly complex models extremely easy.  Distribution disks of this proprietary program contain executable images and example data sets.  Software documentation includes SVE theory, installation instructions, input instructions, and example problems.

The proprietary AIRFLOW/SVE software is available for purchase from several vendors, including the following sites on the World-Wide Web:

IGWMC homepage

Scientific Software Group homepage

API FREE-PRODUCT RECOVERY (API-FPR) MODELS

API has developed a series of models for evaluating the recovery of free-product LNAPL.  The software is programmed in the Microsoft Excel™ spreadsheet environment, and has the ability to calculate free-product recovery for single-  and dual-pump wells, for skimmer wells, and for trenches.  One worksheet in the spreadsheet models is used for entry of basic data.  A second worksheet is used to calculate LNAPL-layer specific volume and relative permeability parameters.  The third worksheet is used to view LNAPL and water saturation profiles through the LNAPL-contaminated zone, and the LNAPL relative permeability profile.  The fourth worksheet calculates LNAPL recovery.

The API Free-Product Recovery (FPR) models are public-domain software that was developed by the Environmental and Water Resources Engineering Program of the University of Texas at Austin on behalf of API, and is maintained by API.  A manual is supplied with the software package, and provides representive values of the various parameters necessary, together with examples of how to apply the models.  A fully-functional freeware version is available at the API site on the World-Wide Web:

API

BIOSLURP

Bioslurping (vacuum-enhanced recovery) is an innovative remedial technology that increases gradients in water and oil with minimal fluctuations in the fluid tables, and thus helps to reduce volume of residual product and enhance free-product recovery.  BIOSLURP is a finite-element code designed to simulate the movement of three phases (water, oil, and vapor) and multicomponent transport in groundwater and in the unsaturated-zone vapor phase, for use in the design and evaluation of bioslurping systems.

BIOSLURP can be used to optimize the recovery of LNAPL, water, and vapor by identifying mechanisms for minimizing NAPL entrapment in the saturated/unsaturated zones, and simultaneously can simulate multispecies aqueous and vapor-phase transport in unconfined aquifers.  BIOSLURP also can be used to simulate coupled flow of water and LNAPL with a static atmospheric gas phase, and thus can be used to design NAPL recovery and hydraulic containment systems for free-phase hydrocarbon LNAPL and the associated dissolved-phase plume under complex hydrogeological conditions.

The proprietary BIOSLURP software is available for purchase from the Scientific Software Group site on the World-Wide Web:

Scientific Software Group homepage

BIOSVE
Field situations often require application of tools to evaluate different remediation schemes prior to implementation.  BioSVE incorporates SVE, vacuum-enhanced recovery (bioventing) and biodegradation into a single screening model.  While screening tools usually require extensive site data (which can be expensive or impossible to collect in the available time frame), BioSVE allows site evaluation and remedy design to be completed quickly, using the results of only a few sampling events.  Vacuum-enhanced recovery (bioslurping), coupled with biodegradation, is a popular emerging cleanup technology, and BioSVE takes advantage of this industry trend with useful tools for hydrocarbon contaminant sites.  A typical hydrocarbon spill/leak may contain from 20 to more than 100 components, and BioSVE can simulate recovery and degradation of up to 250 components.  BioSVE allows for modeling of contaminants partitioned among water, vapor, free hydrocarbon and solid phases, enabling the user to develop remediation strategies for free-product recovery, SVE, natural or engineered biodegradation, etc.

The proprietary BioSVE software is available for purchase from the Scientific Software Group site on the World-Wide Web:

Scientific Software Group homepage

HYPERVENTILATE
HYPERVENTILATE is an interactive software guidance system for evaluating the feasibility of using SVE at a specific site based on site and contaminant characteristics. HYPERVENTILATE is designed to (1) identify the site data required to evaluate the SVE system, (2) evaluate soil permeability test results, (3) approximate the minimum number of extraction wells likely to be needed in a full-scale system, and (4) estimate the system's desired and maximum removal rates.  HYPERVENTILATE contains a guidance system based upon recent SVE research and analytical methods to evaluate soil permeability test results and complete a screening-level design of an SVE system.  Sensitivity analyses of HYPERVENTILATE results can easily be performed using the program to assess uncertainties associated with site characteristics and contaminant distribution in the subsurface.

HYPERVENTILATE is menu-driven, provides for interactive data entry and editing, and includes the Spinnaker Plus system to review graphical guidance information. Program output is in tabular and graphical format.  The distributed disks contain executable image, guidance data sets, example data sets and a single-use runtime version of the Spinnaker Plus Version 2.5 program.  The documentation includes installation instructions and a user's manual.

The HYPERVENTILATE software is available for purchase from the International Groundwater Modeling Center (IGWMC) site on the World-Wide Web:

IGWMC homepage

Although the HYPERVENTILATE computational module is in the public domain, the version for sale by IGWMC is considered proprietary because of inclusion of the licensed graphics software.

BIOPLUME III

BIOPLUME III is a 2-D, finite-difference model for simulating the natural attenuation of organic contaminants in groundwater resulting from the processes of advection, dispersion, sorption, and biodegradation.  Biotransformation processes are potentially important in the restoration of aquifers contaminated with organic pollutants. As a result, these processes require evaluation in remedial action planning studies associated with hydrocarbon contaminants.  The software is based on the US Geological Survey's (USGS) method of characteristics (MOC) solute transport code, and solves the solute transport equation six times to determine the fate and transport of the hydrocarbons, electron acceptors, and reaction by-products. Aerobic and anaerobic biodegradation reactions can be simulated using three different kinetic expressions:  first-order decay, instantaneous reaction and Monod kinetics.

BIOPLUME III integrates the MOC code with a sophisticated ground-water modeling platform known as EIS.  A graphical platform allows the user to easily create, enter and edit data for simulations.  The model generates a standard output file that lists the input data for the specific model simulation, followed by computed values of head, and contaminant concentration maps.  The results of model simulations also can be presented graphically, by extracting model output and processing with a graphics generation software program.

The public-domain BIOPLUME III package was developed by Groundwater Services, Inc. (GSI) on behalf of the USEPA and the Air Force Center for Engineering and the Environment (AFCEE), and is maintained by the USEPA's Center for Subsurface Modeling Support ( CSMoS).  It can be obtained free of charge from the CSMoS page on the World-Wide Web:

CSMoS

screenshot

GMS
The Department of Defense Groundwater Modeling System (GMS) is an advanced and comprehensive groundwater-modeling package.  The program was developed under the direction of the U.S. Army Corps of Engineers (USACE), with support from the Department of Defense (DoD), the Department of Energy ( DoE), and the USEPA.  The entire GMS system consists of a graphical user interface (the GMS program) and a number of analysis codes that originated with other authors or organizations (MODFLOW, MT3D, MODPATH, FEMWATER). Several types of models are supported and facilities are provided to share information between different codes and data types.

GMS provides complete support for the USGS MODFLOW 3D finite difference, MODPATH 3D particle tracking, MT3DMS 3D multi-species contaminant transport, the Department of Energy RT3D 3D bioremediation transport, the recently released SEAM3D 3D bioremediation transport, and the Army Corps SEEP2D 2D finite element, and FEMWATER 3D finite element groundwater models.  Support for other groundwater models currently is being added, including USEPA's NUFT and UTCHEM.  Tools are provided for site characterization, model conceptualization, mesh and grid generation, geostatistics, telescopic model refinement, automated model calibration, and output post-processing. Several groundwater modeling data types can be accommodated, including TINS, boreholes, 2D mesh, 2D grid, 2D scatter points, 3D mesh, 3D grid, 3D scatter points, and solids.  The program enables common information to be shared among different data types and groundwater models.

GMS is completely graphical, and can display a defined groundwater model in either plan view or 3D oblique view, and can be rotated interactively.  Cross-sections and fence diagrams may be cut anywhere in the model.  Hidden surface removal, and color and light source shading can be used to generate highly photo-realistic rendered images.  Contours, color fringes, and 3D iso-surfaces can be used to display the variation of input data or computed results.  In addition, the system is completely modular, and the various modules can be combined to present subsurface data graphically (visualization modules), construct and run simulations of groundwater flow and contaminant migration (simulation modules), and present the results of simulations (predictive modules).

GMS is available for purchase from several vendors.  General information and purchase pricing can be obtained at the following sites on the World-Wide Web:
MODEL FOR MULTIPHASE FLOW AND TRANSPORT OF MULTICOMPONENT ORGANIC LIQUIDS (MOTRANS)

MOTRANS is a finite element model that can be used to simulate the movement of water, dense or light NAPL, and air, and transport of up to five partitionable species in two-dimensional vertical sections through saturated and unsaturated zones.  Vapor-phase flow may be considered explicitly or assumed to be at constant pressure.  Consideration of NAPL flow is eliminated locally if NAPL is absent or exists at residual saturation.  Convective-dispersive transport in water, NAPL and gas phases are analyzed assuming local equilibrium partitioning among the fluid phases and with the solid phase, or optionally using a first-order non-equilibrium mass transfer model.  Interphase mass transfer and compositional dependence of phase densities are considered.  MOTRANS utilizes a three-phase van Genuchten model for saturation-pressure-permeability relations and considers hysteresis in oil permeability resulting from oil entrapment.  It can be used to simulate water movement only, oil movement with steady-state water movement, coupled oil-water movement, or coupled air-oil-water movement.

The MOTRANS user interface includes menu-driven pre- and post-processing programs, to simplify generation of data files, and graphical input of spatially variable properties and time-dependent boundary conditions.  The MOTRANS user interface can be used to generate output suitable for manipulation and display in other graphic software packages; plots of cumulative mass in the system through time; and contour plots of phase saturations and species concentrations.

The proprietary MOTRANS software is available for purchase from the IGWMC site on the World-Wide Web: IGWMC homepage

SWANFLOW
SWANFLOW is a three-dimensional finite-difference code for simulating the flow of water and an immiscible nonaqueous phase under saturated and unsaturated near-surface conditions.  The code may be used in many situations requiring the analysis of immiscible flow, such as simulating the migration of organic chemicals, analyzing the effects of remedial technologies at hazardous waste sites where immiscible fluids are encountered, and evaluating the migration and clean up of fuel spills and leaks.

The governing equations are a simplified subset of the three-phase flow equations for porous media commonly used in petroleum reservoir simulation, and are expressed in terms of volumetric water saturation and fluid pressure in the immiscible fluid.  SWANFLOW has been verified against two analytical solutions and benchmarked against several other numerical models.  It should be noted that mass transfer between phases is not considered, i.e. NAPL cannot dissolve in water or evaporate.

SWANFLOW runs in batch mode under MS DOS.  Supplied documentation includes installation instructions, theory, user's manual, and example problems.  Example data sets are provided, which can be copied and edited with a text editor for individual problems (Note that SWANFLOW is data-intensive!).  Results are saved in a text file for evaluation by the user.

The public-domain SWANFLOW package was developed by GeoTrans, Inc., and can be obtained free of charge from the IGWMC page on the World-Wide Web: IGWMC

DECISION SUPPORT SOFTWARE
Decision support systems are computer-based systems that integrate site-specific data, application of models, and structured decision processes to facilitate decision-making, and have been developed as tools for dealing with problems that are broadly defined or where conventional programming techniques may be difficult or impractical to apply.  A "toolbox" approach lends flexibility for solving a variety of types of problems and makes the solving of many problems accessible to nonexperts.  Unlike expert systems, however, where the problem-solving process generally is controlled by the software, a DSS supports, rather than replaces the decision-making of the user.  The user must decide how to apply the available tools towards the solution to a particular problem.

A number of different types of Decision Support software have been developed to support analysis of decisions pertaining to environmental management.  The optimal DSS should integrate, analyze, and present environmental information to remediation project managers, and assist them in identifying effective, and cost-effective cleanup strategies.  At the same time, the DSS should balance the sophistication needed to address the wide range of complicated sites and site conditions present at DoD facilities with ease of use, to the extent that the system should not require data that may be unknown, and should have robust error-checking algorithms during the process of data input, to ensure that the nature of the problem is adequately defined.  Most DSS packages include several of the following capabilities:

  • Site-characterization data analysis, including visualization of site-characterization data and data integration,
  • Analysis of nature and extent of contamination,
  • Data worth analysis,
  • Remedial action analysis, which includes optimization of remedial design, in addition to comparison of different remedial alternatives,
  • Human health risk analysis, and compliance with regulatory requirements, and
  • Economic cost/benefit analysis.
A comprehensive DSS package can be used to evaluate conditions at a site using one or several of the analysis categories listed above.  For example, DSS exist that can simulate several remedial action alternatives for multiple contaminants, and provide a risk assessment and cost/benefit analysis for each alternative. The variety of waste management problems and environmental conditions is so vast that, currently, no DSS system covers all aspects relevant to environmental remediation problems.  Care must be taken by the analyst to match the capabilities of the DSS with the problem requiring a decision.

The features of several currently-available commercial and public-domain DSS packages are described in this subsection.  Click on the appropriate link in the following table to view a description of the selected DSS software. 

DSS SOFTWARE PACKAGES REVIEWED IN THIS SUBSECTION
DSS Software Package Ease of Use a/ Availabilityb/ Applications
BIOSCREEN E P Evaluation of natural attenuation of fuel hydrocarbons in groundwater
BIOCHLOR E P Evaluation of natural attenuation of chlorinated solvents in groundwater
BIOSOURCE -- P Evaluation of remediation timeframes based on source-zone decay
MAROS E P Evaluation and optimization of monitoring programs
RBCA Toolkit E C Uses risk-based criteria and tools to derive cleanup standards
GS Toolkit E P Evaluate the sensitivity of a groundwater resource to a potential release of COCs
BenefitsFX M C Assist in making defensible remediation decisions through the application of multi-attribute decision analysis methods
MARS M C Simulates migration and recovery of LNAPLs to assist in design of recovery systems
Mass Flux Toolkit E P Compare different mass flux approaches, calculate mass flux from transect data, and apply mass flux to manage groundwater plumes.
RAAS M C Assist in evaluating complete remediation alternatives by combining remedial technologies in new and different ways
SADA E P Compile and evaluate available information to assist users in quickly and cost-effectively making decisions about their site
a/  E  =  easy; M  =  moderately difficult; D  =  difficult.
b/  P  =  public domain; C  =  commercial.

BIOSCREEN
BIOSCREEN is an easy-to-use screening-level DSS model which simulates remediation by natural attenuation (RNA) of dissolved hydrocarbons at petroleum fuel release sites.  The software is based on the Domenico analytical solute transport model, and is programmed in the Microsoft Excel™ spreadsheet environment; it has the ability to simulate advection, dispersion, adsorption, and aerobic decay as well as anaerobic reactions that have been shown to be the dominant biodegradation processes at many petroleum release sites.  Three different types of simulations can be completed: (1) solute transport without decay, (2) solute transport with biodegradation modeled as a first-order decay process (simple, lumped-parameter approach), and (3) solute transport with biodegradation modeled as an instantaneous reaction with multiple soluble electron acceptors including dissolved oxygen, nitrate, and sulfate.

BIOSCREEN is intended to be used in two ways:

  • As a screening model to determine if RNA is feasible at a site; or
  • As the primary RNA groundwater model at smaller sites.
BIOSCREEN can be used to answer two fundamental questions regarding RNA at a site:

  1. How far will the dissolved contaminant plume extend if no engineered controls or source-zone reduction measures are implemented?
  2. How long will the plume persist until natural attenuation processes cause it to degrade and dissipate?
BIOSCREEN uses a simple mass-balance approach to simulate NAPL source-zone dissolution, based on the mass of dissolvable hydrocarbons in the source zone and the rate of hydrocarbons leaving the source zone.  Because an exponential decay in source-zone concentration is assumed, the predicted plume lifetimes can be large, usually ranging from 5 to 500 years.

The Air Force Intrinsic Remediation Protocol for fuel hydrocarbons (Wiedemeier et al., 1999) describes how groundwater models may be used to help verify that natural attenuation is occurring and to predict how far dissolved contaminants might migrate if an RNA remedy were implemented.  At large, complex sites a more sophisticated model such as BIOPLUME probably is more appropriate.  However, at less complicated sites such as service stations, BIOSCREEN may be sufficient to complete the RNA evaluation.

The public-domain BIOSCREEN package was developed by GSI on behalf of AFCEE, and is maintained by the USEPA's CSMoS.  It can be obtained free of charge from the CSMoS page on the World-Wide Web: CSMoS

BIOCHLOR
BIOCHLOR is an easy-to-use screening-level DSS model that simulates RNA of dissolved chlorinated solvents at solvent release sites.  The software is based on the Domenico analytical solute transport model, and is programmed in the Microsoft Excel™ spreadsheet environment; it has the ability to simulate one-dimensional (1-D) advection, 3-D dispersion, linear adsorption, and biotransformation via reductive dechlorination (the dominant biotransformation process at most chlorinated solvent sites).  Reductive dechlorination is assumed to occur under anaerobic conditions and dissolved solvent degradation is assumed to follow a sequential first-order decay process.  Three different types of simulations can be completed: (1) solute transport without decay, (2) solute transport with biodegradation modeled as a sequential first-order decay process (simple, lumped-parameter approach), and (3) solute transport with biodegradation modeled as a sequential first-order decay process with two different reaction zones (i.e., each zone has a different set of rate coefficient values).

BIOCHLOR is intended to be used to evaluate the downgradient distance to which dissolved chlorinated-solvent constituents could migrate in groundwater if no engineered controls or source-zone reduction measures are implemented.  BIOCHLOR uses an analytical solute transport model with sequential first-order decay for simulating in-situ  biotransformation, and can be used to predict the maximum extent of dissolved-phase plume migration, which then may be compared with the actual distances to potential points of exposure (e.g., drinking-water wells, groundwater discharge areas, or property boundaries).

BIOSCREEN can be used to answer two fundamental questions regarding RNA of chlorinated solvents at a site:

  1. Are natural-attenuation processes occurring at rates sufficient that RNA may be an appropriate remedial approach for a particular site?
  2. How long will the plume persist until natural attenuation processes cause it to degrade and dissipate?
The Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Ground Water (USEPA, 1998) describes how groundwater models, in conjunction with other types of analyses, may be used to evaluate the effectiveness of natural attenuation, and to predict how far dissolved contaminants might migrate if an RNA remedy were implemented.  BIOCHLOR is an appropriate tool for use at sites where simplifying assumptions (e.g., uniform direction and rate of groundwater movement, a well-defined source zone, first-order contaminant decay) can be invoked.  At other sites, where these simplifying assumptions are not valid, application of a more sophisticated numerical model such as RT3D would be appropriate.

The public-domain BIOCHLOR package was developed by GSI on behalf of AFCEE, and is maintained by the USEPA's CSMoS.  It can be obtained free of charge from the CSMoS page on the World-Wide Web: CSMoS

BIOSOURCE
BIOSOURCE is an easy-to-use screening-level DSS for estimating remediation timeframes and assessing the uncertainty associated with those estimates.  BIOSOURCE is programmed in the Microsoft Excel™ spreadsheet environment, and incorporates (1) a plotting/statistical tool for analyzing historical source-zone concentration data and determining the uncertainty associated with trends in contaminant source concentrations; (2) a tool for estimating contaminant source attenuation from estimates of source mass and mass flux; (3) process-type models for evaluating temporal changes in concentrations in dissolved-phase systems and in NAPL-affected source zones; and (4) a database of source decay rate constants for petroleum fuel constituents and chlorinated solvents, derived from historical information collected at nearly 400 sites, each having at least three years of monitoring data.  (Note that the source decay constant is used to represent the long-term removal of contaminant mass from source zones, and is not the same as a biodegradation rate constant or a bulk attenuation rate for dissolved-phase contaminants.)

The public-domain BIOSOURCE package currently is in development by GSI on behalf of AFCEE, and has not yet been released for unrestricted use.  Additional information may be obtained from GSI's page on the World-Wide Web: GSI

MAROS
The Monitoring and Remediation Optimization System (MAROS) software was developed to provide site managers with a strategy for formulating appropriate long-term groundwater monitoring programs that can be implemented at lower costs.  The MAROS software optimizes a site-specific monitoring program that is currently tracking contaminant migration in groundwater.  MAROS is a Microsoft Excel™-based decision support tool that uses statistical methods applied to current and historic site-specific contaminant-concentration data, and also accounts for hydrogeologic factors (e.g. seepage velocity) and the location of potential receptors (e.g., wells, discharge points, or property boundaries).  Using this site-specific information, the software tool suggests an optimization plan for the current monitoring system that is cabable of achieving the objectives of the monitoring program in an efficient and cost-effective manner.

The MAROS public-domain software was developed by GSI and the University of Houston on behalf of AFCEE, and can be obtained free of charge from GSI's GSI

Risk-based corrective action (rbca) toolkit
The RBCA Tool Kit for Chemical Releases was designed to meet the requirements of the American Society for Testing and Materials (ASTM) Standard Guide for Risk-Based Corrective Action (ASTM, 2000 and 2002).  This software is a comprehensive modeling and risk characterization package for Tier 1 and Tier 2 RBCA evaluations for chemical release sites.  The Tool Kit combines contaminant transport models and risk assessment tools to calculate baseline risk levels and derive risk-based cleanup standards for a full array of soil, groundwater, surface-water and air exposure pathways.  The ease-of-use features and streamlined graphical interface features of this software make it an essential tool for handling RBCA calculations for problems ranging in scope from simple to complex problems.

The RBCA Toolkit includes f ate and transport models for all exposure pathways, capable of addressing a wide array of chemicals, including petroleum fuels and chlorinated solvents.  Multiple points of exposure can be evaluated in the same simulation.  A wide range of default transport parameters is provided for various soil types.  In addition to steady-state air, soil, and groundwater exposure models, the toolkit can be used to conduct transient groundwater modeling analyses to assist in estimating not only the range of contaminant concentrations that might occur at an exposure point, but how soon exposure could occur.

The toolkit includes an extensive chemical database covering a wide array of chemicals, including organic solvents, petroleum hydrocarbons (including TPH fractions), pesticides, metals, and more.  After the user has identified the chemical(s) of concern, the necessary chemical properties are loaded automatically from the database.  The database can be expanded and customized by the user for state-specific values.

The streamlined graphical interface of the toolkit guides the user through the RBCA evaluation process.  Features include convenient selection/conversion of units, and options to save/retrieve data, for efficient file storage.

RBCA for Chemical Releases Main Screen
RBCA for Chemical Releases Main Screen
After the risk-based calculations have been completed for a site, the software produces report-quality output tables of baseline risk and cleanup standards and a report-ready summary for each identified chemical of concern.

The proprietary RBCA Toolkit software is available for purchase from GSI's site on the World-Wide Web: GSI

Groundwater Sensititity (GS) Toolkit
The Groundwater Sensitivity Toolkit was developed by GSI for the American Petroleum Institute (API) and the California methyl tert-butyl ether (MTBE) Research Partnership, and was designed to help site managers, water purveyors and regulators evaluate the sensitivity of a groundwater resource to a potential release of contaminants of concern (e.g., an MTBE-oxygenated fuel) at a particular site.  The toolkit addresses three aspects of sensitivity:  Resource Value, Receptor Vulnerability and Natural Sensitivity.  The user supplies site-specific information and the toolkit returns a "scorecard" addressing the three aspects of sensitivity.  Although this utility was designed specifically for petroleum hydrocarbon releases, it also can be used when chlorinated hydrocarbon compounds and inorganic constituents are the contaminants of concern.  The toolkit is supplied with a user-friendly graphical interface, runs in the Microsoft ExcelTM spreadsheet environment, and comes with a comprehensive guidance manual.

The public-domain Groundwater Sensitivity Toolkit was developed by GSI on behalf of API, and can be obtained free of charge from the API page, or from GSI's page on the World-Wide Web:
API
GSI

BenefitsFX
BenefitsFX is a DSS software package intended to assist decision makers and risk managers in making defensible remediation decisions through the application of multi-attribute decision analysis methods.  BenefitsFX is based on the US Department of Energy (DOE) code Benefits Analyzer, which was developed by Sandia National Laboratories and is being applied to evaluate innovative technology proposals for the DOE's Uranium Mill Tailings Remedial Action (UMTRA) Project, and to evaluate alternative closure configurations for DOE High Level Waste tank initiatives.   BenefitsFX utilizes
  • user-defined evaluation criteria to select technologies or remedy alternatives and
  • user-defined weighting factors to prioritize the importance of the evaluation criteria.
  • The user-friendly graphical interface has real-time visualization capabilities for displaying the results of comparison of alternatives.
The proprietary BenefitsFX software package was developed by DecisionFX, and is available for purchase from DecisionFX's site on the World-Wide Web:

DecisionFX
MULTIPHASE AREAL REMEDIATION SIMULATOR (MARS)
The MARS (Multiphase Areal Remediation Simulator) software can be used to model migration and recovery of LNAPLs in unconfined heterogeneous, anisotropic aquifers.  The MARS flow module simulates recovery and migration of water and LNAPL in unconfined aquifers following an LNAPL spill or leak.  It also can simulate NAPL recovery with skimmers and trenches, optimize the number and location of recovery points, and optimize recovery rates for water and oil.  MARS also creates input files for the BIOF&T model which simulates multispecies dissolved-phase transport in heterogeneous, anisotropic, fractured media, or unfractured granular porous media.  The BIOF&T transport module is invoked to simulate 2-D or 3-D multispecies dissolved-phase transport originating at the free and residual NAPL source.  MARS generates the initial distribution of NAPL specific volume in the domain for BIOF&T which models the aqueous phase transport, and computes and updates the temporal and spatial variation in the NAPL source during the simulation.

This software includes a user-friendly pre-processor, mesh editor and post-processor.  The pre-processor and mesh editor are used to create input data files for MARS, and include modules for mesh generation, assigning heterogeneous and anisotropic soil properties to zones, defining boundary conditions for water and oil phases, and assigning spatially-variable recharge across the model domain.  MARS output includes the simulated water and oil-phase pressures, water and oil-phase velocities at each node, total volume of water and oil through time, and water and oil recovery/injection rates for each source or recovery-point location through time.  The volumes of free oil and residual oil and their spatial distributions through time also are calculated.

The proprietary MARS software is available for purchase from the Scientific Software Group site on the World-Wide Web:

Scientific Software Group homepage

Mass Flux Toolkit
The Mass Flux Toolkit, developed for the Department of Defense ESTCP program, is an easy-to-use, Microsoft® Excel based software tool that enables users to learn about different mass flux approaches, calculate mass flux from transect data, and apply mass flux values to manage groundwater plumes. The Toolkit presents the user with three main options:

  • A module to calculate the total mass flux across one or more transects of a plume, calculate the uncertainty in the calculation, and plot mass flux vs. distance to show the effect of remediation/impact of natural attenuation processes;
  • A module allowing users to perform critical dilution calculations for plumes approaching production wells or streams. An additional feature calculates the capture zone of the supply well and compares it to the transect used to calculate the mass flux, directing the user to alter the transect dimensions if the transect does not encompass the capture zone; and
  • A module that provides a review of theory and methods of estimating mass flux.
Uncertainty in mass flux estimates is a key issue in using mass flux as a metric. The Toolkit provides three options for analyzing uncertainty in the total mass flux estimates derived from the transect method. One option utilizes the Monte Carlo approach to analyze uncertainty in the actual concentration, hydraulic conductivity, and gradient measurements. With this tool, groundwater practitioners can estimate the accuracy of the hydrologic measurements that are being used for the mass flux calculation. The second option provides a tool for estimating the contribution of each individual observation to the total mass flux. The third method shows the uncertainty involved in the interpolation scheme that is used to calculate mass flux.

The Mass Flux Tool Kit can be downloaded from the GSI web site

Remedial Action Assesment System (RAAS)

RAAS is a DSS package designed to assist site managers in evaluating complete remediation alternatives by combining remedial technologies in new and different ways, to create holistic cleanup alternatives for a particular site.  RAAS also is capable of comparing the performance of preliminary alternatives using criteria including potential ranges of cost, residual contaminant concentrations, and projected reductions in volume, toxicity, and mobility of contaminants.

RAAS is supplied with site-specific information regarding physical and chemical characteristics, and the site regulatory framework.  RAAS checks and accepts the site information, operating assumptions, and cleanup objectives, and then asks a series of questions to assist in refining site cleanup strategies, requirements and constraints, and remediation objectives.  RAAS then generates a short list of cleanup alternatives based on one or more environmental remediation technologies. RAAS can be queried for more information about the technologies and their potential effectiveness at the site.  The site manager then is equipped to make informed decisions regarding cleanup alternatives, with supporting documentation.

RAAS was developed at the Pacific Northwest National Laboratory (PNNL) on behalf of DOE, and is available to government and public-sector users at nominal cost.  Additional information is available at the RAAS page at Battelle PNNL

Spatial Analysis and Decisioin Assistance (SADA)
The Spatial Analysis and Decisioin Assistance (SADA) software package is an environmental DSS that integrates tools from several fields, including geospatial analysis, statistical analysis, human-health risk assessment, cost/benefit analysis, sampling design, and decision analysis, into a dynamic and interactive DSS environment.  Each module can be used independently or collectively to address site-specific concerns when characterizing a contaminated site, determining the location of future sampling, and during the design of remedial measures. SADA was designed to simplify and streamline several of the processes in environmental characterization, risk assessment, and cost/benefit analysis to compile and evaluate available information to assist users in quickly and cost-effectively making decisions about their site.  SADA incorporates visualization tools to assist environmental professionals in examining the data within a spatial context; these visualization tools are described in greater detail on the Visualization Software page.

The SADA decision support tool was designed to directly address environmental emediation questions, such as

  1. the location and size of the zone of contamination,
  2. the size of the zone requiring cleanup at a specified contaminant threshold concentration or risk level,
  3. the level of confidence associated with predictions of the zone of contamination or cleanup zone,
  4. the costs for remediating the cleanup zone,
  5. the potential human health risks, and
  6. the optimal location for the next set of samples to best define the extent of contamination.
SADA was designed for analyzing spatial data, and can be used to evaluate a wide range of conditions in several environmental media (e.g., contaminants in groundwater, soil, sediment, or surface water; multiple contaminants at a single site).  The spatial analyses place all relevant site information into a visual context, which facilitates the production of 2-D and 3-D maps and plots, including maps showing contaminant concentrations, recommended cleanup zones, and human-health risk, that can be used to support data interpretation and decision making.  SADA also can be used to generate cost-benefit curves to display the costs associated with remediation at various cleanup thresholds.  The statistical and geostatistical tools incorporated in SADA also can be used to identify new sampling locations based on analyses of the existing data.

In addition to processing information and generating results in a clear, transparent manner, thereby directly supporting decision processes, the software also can serve as a communication tool between technical and non-technical audiences. The end result is that SADA can be used to facilitate decisions about a given site in a quick and cost effective manner.

In order to allow presentation of environmental data by location associated with site characteristics, SADA can accept map layers from a GIS saved in a Data eXchange Format (DXF).  Multiple layers can be imported into SADA, and the user can control the order and coloring schemes of the various layers.  In addition, the user can select a sub-region of the site to direct the geospatial and risk analyses.  This user-defined polygon will only consider data points within the interior of the delimited region when performing the analyses.

The SADA graphical user interface is logically structured to facilitate use of the options in the software.  Although SADA is easy to use, users require training in order to apply SADA correctly and efficiently.  An analyst with a background in environmental remediation and a basic knowledge of database operations, human health risk assessment, and statistics/ geostatistics can use SADA effectively after one or two days of training.  A detailed online help system is supplied with the software package, and provides examples of how to apply the visualization tools.  Technical support is available through e-mail.

SADA is public-domain software that was developed, and is maintained by The Institute for Environmental Modeling at the University of Tennessee, on behalf of the USEPA and the US Nuclear Regulatory Commission (NRC).  A fully-functional freeware version is available at The Institute for Environmental Modeling

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