IMPACT Users Manual

August 2009 TABLE OF CONTENTS Environmental IMPACT™ User Manual i INTRODUCTION .............................................................................................................................................. 1 1.1 WHAT IS IMPACT? ................................................................................................................................... 1 1.2 IMPACT FOR DERIVED RELEASE LIMITS .................................................................................................. 1 1.2.1 Calculation of Concentrations and Doses ........................................................................................ 1 1.2.2 Calculation of Derived Release Limits (DRLs) ................................................................................. 2 1.3 GENERAL APPROACH TO IMPACT MODELING ......................................................................................... 3 1.4 USER CHARACTERISTICS ........................................................................................................................... 3 1.5 NEW CHANGES IN VERSION 5.4.0 .............................................................................................................. 4 1.6 MOTES ON ALIGNMENT WITH CSA STANDARD (N288.1-08) ..................................................................... 5 1.7 GETTING ANSWERS TO IMPACT QUESTIONS ............................................................................................ 5 1.7.1 IMPACT User Manual ...................................................................................................................... 5 1.7.2 Trouble Shooting and Problem Reporting ........................................................................................ 6 1.8 ACKNOWLEDGMENTS ................................................................................................................................ 6 INSTALLATION ................................................................................................................................................ 1 2.1 BEFORE YOU BEGIN .................................................................................................................................. 1 2.2 UNDERSTANDING THE OPERATING SYSTEM ............................................................................................... 1 2.3 SYSTEM REQUIREMENTS ........................................................................................................................... 1 2.4 INSTALLING IMPACT ............................................................................................................................... 1 2.5 WHERE TO GO FROM HERE… ................................................................................................................... 6 MODEL FEATURES AND FUNCTIONS ....................................................................................................... 1 3.1 IMPACT FILES ......................................................................................................................................... 1 3.2 STARTING IMPACT .................................................................................................................................. 2 3.3 BASIC CONCEPTS ....................................................................................................................................... 2 3.3.1 Modelling .......................................................................................................................................... 3 3.3.2 Scenario ............................................................................................................................................ 3 3.3.3 Simulations ....................................................................................................................................... 3 3.3.4 Polygons ........................................................................................................................................... 4 3.3.5 Blocks ............................................................................................................................................... 4 3.3.6 Class ................................................................................................................................................. 4 3.3.7 Type .................................................................................................................................................. 4 3.3.8 Attributes .......................................................................................................................................... 5 3.3.9 Aliases............................................................................................................................................... 5 3.3.10 Pathways and Links .......................................................................................................................... 5 3.3.11 Probabilistic ..................................................................................................................................... 6 3.3.12 Data Storage ..................................................................................................................................... 6 3.4 WINDOWS .................................................................................................................................................. 6 3.4.1 Biosphere Window ............................................................................................................................ 6 3.4.3 Polygon Contents Window .............................................................................................................. 10 3.4.4 Attribute Windows .......................................................................................................................... 12 ii Table of Contents Environmental IMPACT™ User Manual 3.4.5 Contaminants Window .................................................................................................................... 13 3.4.6 Global Reactions Window .............................................................................................................. 15 3.4.7 Global Radiation Energy Input Window ........................................................................................ 16 3.4.8 Database Window ........................................................................................................................... 18 3.4.8 Messages Window ........................................................................................................................... 19 3.4.9 References Window ......................................................................................................................... 20 3.4.10 Graphic Analyses Windows ................................................................................................................. 21 3.5 TOOLBARS ............................................................................................................................................... 22 3.6 DIALOGUES ............................................................................................................................................. 23 3.6.1 Source Dialogue............................................................................................................................ 23 3.6.2 Baseline Inflow Dialogue ............................................................................................................... 26 3.6.3 Meteorology Dialogue .................................................................................................................... 29 3.6.4 Scale Dialogue................................................................................................................................ 30 3.6.5 Fill Dialogue .................................................................................................................................. 31 3.6.6 Transmogrify Dialogue ................................................................................................................... 32 3.6.7 Run Dialogue .................................................................................................................................. 33 3.7 MENU COMMAND SUMMARY .................................................................................................................. 34 3.7.1 File Menu........................................................................................................................................ 34 3.7.2 Edit Menu ....................................................................................................................................... 37 3.7.3 View Menu ............................................................................................................................................. 37 3.7.4 Biosphere Menu .............................................................................................................................. 38 3.7.5 Polygon Menu........................................................................................................................................ 39 3.7.6 Scenario Menu ................................................................................................................................ 39 3.7.7 Simulate Menu ................................................................................................................................ 40 3.7.8 Output Menu ................................................................................................................................... 40 3.7.9 Polygon Window Menu Bar ............................................................................................................ 42 CREATING A SCENARIO ............................................................................................................................... 1 4.1 CREATING AN IMPACT SCENARIO FILE .................................................................................................... 1 4.2 IMPORTING DATA ...................................................................................................................................... 1 4.3 DEFINING THE BIOSPHERE ......................................................................................................................... 2 4.3.1 Calculating a Map Scale and Boundary ........................................................................................... 2 4.3.2 Importing Background Images ......................................................................................................... 7 4.3.3 Defining Meteorology ....................................................................................................................... 7 4.3.4 Defining Settling and Washout ....................................................................................................... 11 4.4 DEFINING REFERENCES ........................................................................................................................... 11 4.4.1 Creating New References ............................................................................................................... 11 4.4.2 Modifying References ..................................................................................................................... 12 4.5 DEFINING CONTAMINANTS ...................................................................................................................... 12 4.5.1 Contaminant Name Constraints ..................................................................................................... 12 4.5.2 Contaminant Type .......................................................................................................................... 13 4.5.2 Contaminant Attributes ................................................................................................................... 13 4.5.3 Global Reactions ............................................................................................................................ 14 Table of Contents iii Environmental IMPACT™ User Manual 4.6 CREATING A DATABASE .......................................................................................................................... 15 4.6.1 Considerations When Creating a Database ................................................................................... 15 4.6.2 Defining New Block Types .............................................................................................................. 16 4.6.3 Specifying Global Attributes ........................................................................................................... 18 4.6.4 Correlated Random Numbers. ............................................................................................................... 22 4.7 CREATING POLYGONS.............................................................................................................................. 23 4.7.1 Generic Polygons ........................................................................................................................... 23 4.7.2 Closed Polygons ............................................................................................................................. 24 4.7.3 Specifying Polygon Attributes ........................................................................................................ 24 4.8 CREATING BLOCKS .................................................................................................................................. 28 4.8.1 Air Blocks ....................................................................................................................................... 29 4.8.2 Soil .................................................................................................................................................. 30 4.8.3 Porewater Blocks ............................................................................................................................ 31 4.8.4 Groundwater Blocks ....................................................................................................................... 31 4.8.5 Sediment ......................................................................................................................................... 32 4.8.6 Small Lake ("Pond") Blocks ........................................................................................................... 33 4.8.7 Coastal Water Blocks ..................................................................................................................... 34 4.8.8 River Blocks .................................................................................................................................... 35 4.8.9 Terrestrial Animal Blocks ............................................................................................................... 38 4.8.10 Terrestrial Plant Blocks .................................................................................................................. 39 4.8.11 Aquatic Animal Blocks.................................................................................................................... 40 4.8.12 Aquatic Plant Blocks ...................................................................................................................... 40 4.8.13 Human Blocks ................................................................................................................................. 41 4.8.14 Source Blocks ................................................................................................................................. 43 4.8.15 Plume Blocks .................................................................................................................................. 48 4.8.16 Monitor Blocks ............................................................................................................................... 51 4.8.17 Aliases............................................................................................................................................. 57 4.9 MANIPULATING POLYGONS AND BLOCKS ................................................................................................ 57 4.9.1 Selecting Polygons and Blocks ....................................................................................................... 58 4.9.2 Naming Polygons and Blocks ......................................................................................................... 58 4.9.3 Moving Polygons and Blocks ......................................................................................................... 58 4.9.4 Deleting Polygons and Blocks ........................................................................................................ 59 4.9.5 Editing Polygon Shapes .................................................................................................................. 60 4.9.6 Editing Polygon and Block Attributes ............................................................................................ 61 4.9.7 Transmogrifying Blocks .................................................................................................................. 62 4.9.8 Copying and Pasting Blocks and Links .......................................................................................... 63 4.10 LINKING POLYGONS AND BLOCKS ........................................................................................................... 63 4.10.1 Implicit Links .................................................................................................................................. 64 4.10.2 User-defined Links .......................................................................................................................... 64 4.10.3 Specifying Input and Output Fractions .......................................................................................... 65 4.10.4 Removing Links .............................................................................................................................. 66 4.10.5 Link Limitations .............................................................................................................................. 67 4.11 EXPORTING .............................................................................................................................................. 76 iv Table of Contents Environmental IMPACT™ User Manual OUTPUTS ........................................................................................................................................................... 1 5.1 SPECIFYING OUTPUT .................................................................................................................................. 1 5.1.1 Setting Up Monitor Blocks ............................................................................................................... 1 5.1.2 Selecting Monitors for Output .......................................................................................................... 2 5.2 VERIFYING ATTRIBUTES ............................................................................................................................ 3 5.3 SPECIFYING SIMULATION ATTRIBUTES ...................................................................................................... 4 5.3.1 Duration ........................................................................................................................................... 5 5.3.2 Time step ........................................................................................................................................... 5 5.3.3 Iterations........................................................................................................................................... 5 5.3.4 Files .................................................................................................................................................. 6 5.3.5 Isopleth Run ...................................................................................................................................... 6 5.4 RUNNING SIMULATIONS ............................................................................................................................. 7 5.5 EXAMINING RESULTS ................................................................................................................................ 8 5.5.1 Working with Files ............................................................................................................................ 8 5.5.2 Summary Tables ............................................................................................................................... 9 5.5.3 Graphic Analyses ............................................................................................................................ 11 SPECIAL CASES ............................................................................................................................................... 1 6.1 HONEY ...................................................................................................................................................... 1 6.2 BREAST MILK ............................................................................................................................................ 2 REFERENCES ................................................................................................................................................... 1 APPENDIX ......................................................................................................................................................... 1 A.1 UNITS OF OPERATION ............................................................................................................................... 1 A.2 METEOROLOGICAL CONSIDERATIONS ........................................................................................................ 2 A.3 EFFECTIVE AND NON-STOCHASTIC DOSE CALCULATIONS ......................................................................... 5 INTRODUCTION Environmental IMPACT™ User Manual 1 INTRODUCTION 1.1 What is IMPACT? IMPACT is a customizable tool that allows the user to assess the transport and fate of contaminants through a user-specified environment. It also enables the quantification of human and non-human exposure to those environmental contaminants, and the calculation of associated dose. It can calculate the concentration of any contaminant in a range of media, as well as calculate radiation dose and carcinogenic risk or toxic hazard quotients for humans and other biota. IMPACT 5.4.0 has also given focused consideration to the determination of derived release limits (DRLs) for radioactive contaminants. The graphical user interface (GUI) features make it possible to create or modify scenarios quickly and without the need to change the programming code. Thus, users can construct complex models to simulate the impact of contaminant releases in a wide variety of natural environments without the need for programming skills or the use of multiple and complex model interfaces. 1.2 IMPACT for Derived Release Limits The current version of IMPACT (5.4.0) has been constructed to enable the calculation of Derived Release Limits (DRLs) in accordance with the CANDU Owners Group DRL Guidance Document (EcoMetrix/COG, 2008) and CSA standard N288.1-08. That Guidance Document represents a state of the art understanding of radionuclide fate and transport and human dosimetry and is broadly applicable to all CANDU nuclear facilities in Canada, as well as most instances of radionuclide release and exposure world-wide. The theory and equations embodied in IMPACT are documented in the DRL guidance document (EcoMetrix/COG, 2008) and CSA standard N288.1-08. Earlier versions of IMPACT (4.0 and 4.x releases) have used non-steady state solutions to contaminant transport equations. These generally arrive at a steady-state consistent with the results of this module (IMPACT 5.4.0). However, this module contains only steady-state solutions, as described in the DRL Guidance document. 1.2.1 Calculation of Concentrations and Doses Pathway analysis can be represented as a series of contaminant transfers between environmental compartments (Figure 1.2.1). 1-2 Introduction Environmental IMPACT™ User Manual Figure 1.2.1 Environmental Transport Model The radionuclide concentration (or dose) in any receptor compartment j is: j i ij iX = P X? where the summation is over all compartments, i, transferring into compartment j. If all the values of P ij are known, then the individual Xjs may be calculated for any given release rate X0. 1.2.2 Calculation of Derived Release Limits (DRLs) DRLs are calculated independently for releases to air and to surface water. For any particular source, radionuclide and representative person, the DRL is obtained by dividing the dose per unit release (X9/X0) into the relevant dose limit. For the purpose of DRL calculation, X0 can be an arbitrary 1 Bq•s-1, which leads to DRLs that also have units of Bq•s-1. These may be multiplied by 3.154 x 107 s•a-1 to obtain the DRL in Bq•a-1. Introduction 1-3 Environmental IMPACT™ User Manual DRL = annual dose limit (Sv a )XX (a) (Sv a Bq s)-190-1 -1??????? ? ? ? Details can be found in Annex B Sample calculations in the CSA standard. The determination of a derived release limit can be completed in three ways in DRL mode. The first is to use the DRL Monitor specifically designed for this purpose. This approach is limited by the fact that only one contaminant can be addressed in a simulation. This may be time consuming, depending on the number of contaminants of interest. The second method is to use IMPACT's multiple-DRL run function to iterate through all contaminants. It is equivalent to repeatedly running the DRL monitor method for all contaminants. The third method is to use a regular dose monitor to calculate dose for all contaminants, and then externally back-calculate the release limit using the output provided. This method may save time, but it requires the user to be diligent in ensuring that all restrictions and assumptions of release limits are met (e.g. only single sources, the inclusion of decay products or secondary metabolites, etc.). Details of the specific restrictions and considerations in calculating release limits are provided in EcoMetrix/COG (2008). It is strongly recommended that the user be familiar with these issues before attempting to calculate release limits using the latter approach. 1.3 General Approach to IMPACT Modeling In the simplest sense, IMPACT simulates the transport of contaminants through various environmental media that are represented within a user-defined scenario. Accordingly, the main task of IMPACT modeling is the creation of a scenario. A scenario is simply a collection of all data describing the area to be modeled. These data constitute a hierarchy of information that defines the abiotic and biotic media through which the contaminants of concern will travel. Once the characteristics of these media have been defined and the scenario is complete, a simulation can be performed. A simulation is simply the process during which IMPACT performs a series of calculations to predict the effect of contaminant releases on the modeled environment. The results of the simulation can be displayed in any of several user-specified formats (files, graphs or maps). This output can be examined on its own, or in conjunction with the results of other simulations in order to assess changes in contaminant concentration in any of the media and resulting doses to specified receptors, arising from contaminant release. 1.4 User Characteristics IMPACT will be a relatively complex software package that incorporates numerical algorithms from various scientific disciplines related to contaminant transport, exposure and potential human health effects. Users of IMPACT for the purpose of completing radiological dose or DRL calculations should have a general understanding of the contaminant fate and transport processes involved, as well as specific understanding of human dosimetry. Familiarity with COG standards for dose/DRL calculation, specifically the DRL Guidance Document (Ecometrix/COG, 2008), and familiarity with the operations and surroundings of facilities of interest is required. The software is subject to user limitations, in that the results (output values) may depend on the setting of time steps or the specification of input parameters. 1-4 Introduction Environmental IMPACT™ User Manual The Users Manual and the DRL Guidance Document should be reviewed prior to use of IMPACT and should be available during use. 1.5 New Changes in Version 5.4.0 This new IMPACT version 5.4.0 is consistent with DRL Guidance (EcoMetrix/COG, 2008) and CSA standard N288.1-08. The algorithm related changes and bug fixes made between version 5.2.2 and version 5.4.0 are as follows: ? Some parameters changed from embedded values to input parameters, e.g. air plume stability parameters (S) for buoyant restoring acceleration. ? Creation of two washout ratios (Wr): one for washout to plants and one for washout to soil or pond. ? Changes to sector-averaging algorithms for finite cloud dose model, and provision of a switch between finite cloud and semi-infinite model. ? Changes in plant to animal transfer algorithm to accommodate use of dry weight feed intakes. ? Change in air to animal transfer algorithm for HTO, OBT and C-14. ? Creation of two water occupancy factors (OFw): one for well water and one for lake or river water. ? Constrain HTO to exist in soil porewater, but not in soil. ? Change in irrigation water to plant algorithm (remove land area). ? Change in dictator sources to allow partitioning from dictated media to other media. e.g. dictated air to soil, plants, wells. ? Change to allow conteminant-specific shielding factors, e.g. different volues for pure beta vs gamma emitters. ? Allowance for sector-specific surface roughness values in the atmosphere model. ? Enhanced summary table format options for output of results ? Addition of GIS coordinates (as well as UTM and Lat/Long) for spatial referencing of polygons. This release of IMPACT 5.4.0 is back-compatible only to the previous release of IMPACT version of 5.2.2. Scenarios created by any older versions can't be opened by this version. To upgrade those scenarios that were created by older IMPACT versions the user needs to firstly open these scenarios with IMPACT 5.2.2 and save as 5.2.2 version scenarios, and then those new saved scenarios are loadable by this IMPACT version 5.4.0. Introduction 1-5 Environmental IMPACT™ User Manual 1.6 Motes on Alignment with CSA standard (N288.1-08) Sevaral equations that appear in the N288.1-08 document are either alternative calculations (Eq. 6.10, 6.13) or they explain how an inout parameter Is derived (Eq. 6.12, 6.56, 6.64, 6.74, 7.4) and are not implemented in IMPACT for this reason., Equation 6.70 for contaminant transfer from plant to honey Is not implemented as such becausee IMPACT does not includee a honey bee receptor (see section 6.1 for advice on representing a honey bee as a special case of the terrestrial animal model). Eqution 6.71 for contaminant transfer for soil to animal is not implemented as such, becausee IMPACT uses a single combined soil intake for animals, rather than separating food-borne anddirect soil intakes (the user must determine the combined soil intakes as an inout). Equation 6.21 and 6.22 for progeny ingrowth for are no t Implemented since they are rarely required, IMPACT doesn’t allow branching fraction. Users wishing to explicitly track progeny of isomerictransition are advised to assume(conservatively) that all transition are through the metastable state. 1.7 Getting Answers to IMPACT Questions IMPACT incorporates a vast array of functions, calculations, and parameter information and allows a wide range of user-implemented commands and procedures. Due to the broad scope of IMPACT, it is likely that the user will come up with questions during use of this software. To obtain answers to questions, there are a number of available Help options that the user can easily access. The following sections describe each of the Help options in detail. 1.7.1 IMPACT User Manual Throughout this User Manual, the Windows version of IMPACT is depicted in screen shots and discussed in the text. While some operating systems may differ in some aspects of the appearance of IMPACT on screen, most of the concepts that are discussed apply equally well to Microsoft Windows 2000 and XP operating systems. In the text of this manual, words and concepts are highlighted in a distinctive style that indicates their meaning. ? menu, window or dialogue items are referred to in bold type; ? concepts that are defined elsewhere in this manual are highlighted in italics; ? references to other sections of this manual are underlined. The User's Manual has been written in order to provide a complete overview of all attributes of the IMPACT software. The material provided has been arranged to allow you to gain familiarity with IMPACT’s features and functions in order to utilize the software in an informed and effective manner. To help get it up and running quickly, we recommend that the user read through Chapters 1 to 4. This will minimize the need for back-tracking and associated delays in the processes of creating a scenario, running a simulation, and producing the desired results. 1-6 Introduction Environmental IMPACT™ User Manual 1.7.2 Trouble Shooting and Problem Reporting In the use of IMPACT software, there may be times when operational error messages are generated, signified by a red circle containing a white "X" (see example below). The software has been designed to allow continuation or termination in the event of any such errors. Clicking "OK" on most error messages will allow the user to continue working with IMPACT, or in some cases will cause the program to terminate. In the event of failure of normal response, the program can be terminated through conventional methods using the Task Manager of the PC Operating System. If persistent problems cannot be resolved by consulting the User Manual, they can be reported by e-mail to info@ecometrix.ca. EcoMetrix staff can assist on a fee-for-service basis. 1.8 Acknowledgments The IMPACT Team is: Programming: Gene Shen, Ted Byers, and Lynda Yates Model Development: Don Hart, Neil Morris, Don Lush, Bruce Rodgers Database Development: Alan Burt Graphics: Mike Kesteven Documentation: Gene Shen, Don Hart Beta testing: Irv Benovich (OPG), Sohan Chouhan (AECL), Alan Burt, Neil Morris, Bruce Rodgers. External Verification & Validation: Irv Benovich (OPG), Sohan Chouhan (AECL). Development of IMPACT 5.4.0 was funded in part by CANDU Owner's Group (COG) under work package WP 30449. INSTALLATION Environmental IMPACT™ User Manual 2 INSTALLATION Installing IMPACT is a simple process that can be customized. The following sections outline the procedure for successfully installing IMPACT on your computer. 2.1 Before You Begin Please read the following sections before you install the IMPACT software on your computer. 2.2 Understanding the Operating System IMPACT 5.4.0 has been designed for installation and operation on any Windows® operating systems. This manual assumes that the user is familiar with the standard features of the operating system the user is using, whether it is Windows®2000 or XP. Knowledge of fundamental techniques such as clicking and double-clicking, selecting, dragging, and using menus and windows is assumed. If you are unfamiliar with these techniques, we strongly recommend review of the User Manual for your operating system before attempting to use IMPACT. 2.3 System Requirements IMPACT is a C++ application, therefore it can theoretically run on any operating system. In practice, however, it has only been tested and qualified for Microsoft® Windows 2000 and XP. If you intend to run it on other platforms, contact IMPACT technical support for information on any platform-specific issues you may need to know. A single installer program for Windows® applications is provided on the IMPACT Installation CD. The memory and disk space requirements for IMPACT vary for each platform, but generally IMPACT requires a system with 256 to 512 megabytes of RAM (total) and 100 megabytes of free hard disk space for a full installation. As is the case with any numerically intensive application, IMPACT runs best on the fastest processor you can obtain. Please note that the appearance of IMPACT interface windows might be different between different Windows font settings. Some font settings might cause some contents to be hidden in bottom and right corners. Since IMPACT is not capable of adjusting the opening size of the windows screen setting, the user is advised to use the default Windows operation system font settings. 2.4 Installing IMPACT After obtaining the IMPACT CD, you must launch the installer application by double-clicking on the “IMPACT_COG_540_Setup_16Jun2009.exe” application contained on the CD. The ensuing process will install all program files necessary to run IMPACT, as well as an example database and an electronic version of this User Manual. Please note that the installation can be cancelled at any step in the Setup process by simply clicking the "Cancel" button. 2-2 Installation Environmental IMPACT™ User Manual Once the installer has been launched, you will be presented with the install start-up screen. To continue the Installation, simply click "next" to proceed. Installation 2-3 Environmental IMPACT™ User Manual The following window will be needed to fill in user name and organization name. if the installation is only used by the user who intalled IMPACT, then "Only for me" should be checked, otherwise "Everyone who uses this computer (all users)" should be checked. 2-4 Installation Environmental IMPACT™ User Manual The next window allows you to specify the installation directory. A default directory will be chosen unless the user specifies otherwise through the "browse" option. Installation 2-5 Environmental IMPACT™ User Manual The next step in the installation process is to confirm the setup information that has been provided to this point. If there is any need to cancel the installation process, this can be accomplished by clicking the "Cancel" button to stop the installation. 2-6 Installation Environmental IMPACT™ User Manual Once the installation process is complete, a window will appear notifying the user of the successful installation of IMPACT, and requesting the user to "Finish" the setup procedure. Once this is done, IMPACT will be available for use by clicking on the executable file icon in the destination directory or by clicking on any of the shortcuts established during installation 2.5 Where to Go From Here… Once IMPACT has been installed and registered, the user should read Chapters 3 and 4 to become familiar with the basic concepts and features that are part of the IMPACT model. After reviewing and understanding the concepts presented in Chapters 3 and 4, it is strongly recommended that the user read Chapter 5, which describes the process of running a simulation and accessing and customizing the results of a completed simulation. Chapter 6 contains descriptions of special cases of IMPACT application that may help the user deal with certain unique situations. Appendix A describes technical aspects of the software that the may be of benefit to understand while using IMPACT MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual 3 MODEL FEATURES AND FUNCTIONS 3.1 IMPACT Files The main IMPACT program directory contains several separate files and folders: ? an “IMPACT_COG.exe” file for launching the IMPACT application (double clicking the file icon will start IMPACT); ? 8 support files in the same folder where IMPACT_COG.exe is located. These files are: ModelBase.bin, rtl100.bpl, tee7100.bpl, vcl100.bpl, vclx100.bpl, CC3280MT.DLL, BORLNDMM.DLL; ? a "Data" folder containing all ".bin" files comprising the default database (21 files in total; data files for each of the 15 block classes, a data file for contaminants, a data file for global reactions, a data file for references, a data file for scenario version, a data file for windrose data format and a default windrose file); ? an “icons” folder that contains all user-defined icons (used in creating "blocks", as described in Section 4). The user can add any number of custom icons to the “icons” folder if desired; ? folders for any Scenarios that the user creates or any output generated by using IMPACT. These are only default locations added at the time of installation, and the user may save scenarios or model output to any location. The installed folder is: "C:\\\\Program Files\\\\EcoMetrix Inc\\\\ IMPACT_COG_540\\\\". When creating scenarios or running a simulation, IMPACT generates different types of files. Scenario files contain all of the data that describe the scenario which is being modeled (see definition and discussion in Section 3.3.2). This is the group of files that is created when you choose Save… from the File menu in the main Window. Each distinct scenario created by a user will be comprised of a ".SNR" file (referred to specifically as the "scenario" file) and the Data folder, all located in a unique directory of the users choosing. The data folder will hold the same list of files in the main Data folder in the IMPACT directory (see description on previous page). For the specific scenario, the Data folder will contain files that are specific to that scenario, and may contain a site-specific windrose (rather than the default) and also a site-specific background image file, if one has been imported into the scenario. Output files are created when you run a simulation. They contain the results of the model calculations in a format which the user specifies in the Run dialogue in the Simulate menu (refer to Chapter 5 for a discussion of generating results). When a scenario is created, IMPACT automatically creates an output folder in the user-designated directory selected for the scenario. The user can then instruct IMPACT to direct all output files to that directory, or sub-directories therein. 3-2 MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual 3.2 Starting IMPACT The IMPACT application is started by double-clicking the “IMPACT_COG.exe” file. When IMPACT first starts, it creates a blank scenario file ("Scenario 1"). It also calls the data files (".bin" files) in the "Data" folder in the main IMPACT folder and uses these as the "database" for the scenario. The initial screen represents the Biosphere Window (see Section 3.4.1), and appears as follows: At this point, the user can begin to create a new scenario or chose to open existing scenarios using the Open command in the File pull down menu. IMPACT scenario files can be saved by using the Save command in the File menu, typical of most Windows ® applications. Saving the current scenario can also be accomplished using the Save button ( ) In the Toolbar. 3.3 Basic Concepts Prior to actually running IMPACT, the user should have an understanding of a number of concepts that together form the basis of the model and its capacity to simulate contaminant transport in multi-media environments. This section of the manual provides an overview of each of these key concepts. The following diagram illustrates the associated hierarchy and the interconnectedness of a number of the concepts discussed in this section. MODEL FEATURES AND FUNCTIONS 3-3 Environmental IMPACT™ User Manual Each of these concepts is discussed separately below. 3.3.1 Modelling A model is simply a representation of any given feature and/or process, or collection thereof. The features and processes may be physical, chemical or biological. IMPACT models the collective features and processes that make up the environment (both natural and man-made) by creating a scenario which encompasses a number of polygons and blocks representing environmental features (e.g. soil, water, air, plants, animals and humans) and the contaminants of concern. IMPACT incorporates various equations that mathematically represent the processes responsible for contaminant transport through the represented media during each simulation that is run. 3.3.2 Scenario In the simplest sense, a scenario is simply a collection of all data describing the situation to be modeled. It is composed of a well-defined, connected sequence of features, events and processes. This includes all polygons and blocks that have been created by the user. These data define both the physical (e.g. size, topography, and meteorology) and biological (e.g. animals and plants) characteristics of the area. All the data describing a given scenario are saved to an IMPACT scenario file when you choose the Save command from the File menu or use the Save button command in the Toolbar. 3.3.3 Simulations A simulation is simply the process during which IMPACT performs a series of calculations to predict the effect of contaminant releases on the modeled environment (represented by a given scenario.) The period of time over which a simulation is run is divided into a number of time steps of user-specified length. Each simulation can also be run for one or more iterations, where each iteration provides one of the possible results of the series of calculations, assuming that there is some variability in the input and that the modeling process is probabilistic. Chapter 5 provides a detailed discussion of the processes of running a simulation. 3-4 MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual 3.3.4 Polygons Polygons represent two-dimensional areas of the Earth’s surface with generally uniform characteristics. The two basic polygon types are Land and Surface Water. These two polygon types are used to represent all possible combinations of surface features in the area that is to be represented in the model. Every polygon has two attributes that define its spatial extent within the modeled area: 1. a centroid point, with an X and Y coordinate. The X and Y coordinates can be in Cartesian system or in UTM system; 2. a surface area. Additional user-specified attributes describe physical features of the polygons, such as water depth and flow rate (Surface Water polygons). Section 4.7 introduces the process of creating polygons within a scenario. 3.3.5 Blocks Each polygon may contain one or more blocks, representing environmental media or receptors within the polygon where contaminants may accumulate. Blocks may represent a variety of media or receptors, including soil, air, sediment, animals, plants and various types of humans (e.g. adults, children, or infants). Blocks are defined by both their class and their type. Blocks are represented by distinctive user-selected icons that serve to graphically depict the block when constructing a scenario. The user can create and add any custom icon to the "Icons" folder in the main IMPACT folder. There is no restriction on the number of polygons or blocks that can be created in a scenario. The user can create as simple or complex a scenario as desired. Most blocks do not have a spatial reference point themselves. Instead, they are assumed to reside at the centroid of the polygon in which they are located. Section 4.8 describes the process of creating blocks within polygons. 3.3.6 Class Each block belongs to a specific class (as defined in the "Database") that broadly defines which element of the environment the block represents. Examples of block classes are Human, Terrestrial Animal, Soil, and Pond. Within each class are one or more types that further define the characteristics of a block. This classification system is analogous to the scientific binomial classification of biological organisms, where the first name represents the more general classification of genus (analogous to the block’s class) and the second name denotes the species (analogous to the block’s type). As an example, a block representing the Terrestrial Animal class could be characterized by the type “Cow”, “Pig”, “Goat”, or “Chicken”. There are a fixed number of block classes within IMPACT - the user cannot add or delete classes. The user can create as many different types within each class as required or desired. 3.3.7 Type Block types further define the characteristics of a block of a given class. Block types are important to recognize during creation of a scenario since global attributes specified in the database apply to all blocks of the same type. MODEL FEATURES AND FUNCTIONS 3-5 Environmental IMPACT™ User Manual 3.3.8 Attributes Characteristics of polygons and blocks are described using attributes, which can be quantifiable numbers, discrete values or pointers to other data items. All attributes can contain a reference to a data source, whether that source is a scientific journal article or a ballpark estimate. There are two kinds of attributes in IMPACT: global attributes and local attributes. Global attributes describe a characteristic that is common to all blocks of the same type. For example, the inhalation rate parameter for the Terrestrial Animal type “Cow” is a global attribute. The value assigned to this attribute is assumed to apply to all blocks of type “Cow” in the scenario (i.e., all cows within a scenario are assumed to respire at the same rate). If there were two different types of Cow (e.g. the calf and adult cow) with different inhalation rates, the user would have to create two Cow types in the database (“Cow Adult” and “Calf”, as an example). Global attributes are specified in the Database window (refer to Section 3.4.7) and are fully discussed in Section 4.6 (Creating a Database). Because of the shared nature of global attributes, you must be careful when modifying them. If you change the value of a global attribute, you are changing it for every block of the same type within the scenario. Local attributes are specific to individual blocks. When you change a local attribute you are changing it only for the selected block and it affects only that block in that location. Local attributes are typically used to represent characteristics that vary from block to block, even though the blocks may be of a common type. An example of a local attribute is the depth of a well (represented using Groundwater blocks). Even though several Groundwater blocks may share common global attributes such as porosity or bulk density, each Groundwater block will have a unique depth. Local attributes are specified in any of a series of Attribute windows (refer to Section 3.4.4). 3.3.9 Aliases An Alias block simply serves as a placeholder for another block in certain situations, analogous to a shortcut icon in Windows®. An Alias block is used as a liaison in creating links between the block it represents and a block(s) which is located in different polygon. Aliases are used in IMPACT to create links between media found in different locations (e.g. links between an urban resident and food products originating from a rural farm, or between those same residents and sand and water at a regional swimming beach). The process of creating an alias block is described fully in Section 4.8.16. 3.3.10 Pathways and Links Polygons and blocks can often have more than one input or output, indicating that they receive or discharge contaminants to or from more than one polygon or block along different pathways. The transfer of contaminants from one polygon or block to another is specified by creating a pathway or link between them. IMPACT depicts links on-screen by drawing a line between the two blocks with an arrow pointing to the receiving block (i.e. in the direction of contaminant transfer). 3-6 MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual Links can represent different processes of contaminant transfer, depending on the context. A link between a plant (upstream) and animal block (downstream) represents ingestion, while a link between two lake polygons represents flow of water. Some links can represent more than one process, such as a Water to Human link which can represent both ingestion and dermal exposure pathways (swimming or bathing). Section 4.10 describes the procedure for creating links and also identifies the conceptual processes that links between specified block classes represent. 3.3.11 Probabilistic In some instances, the exact value of a parameter is not known, but a range of possible values, each with a certain probability of occurrence, has been defined. IMPACT has the capacity to represent this uncertainty. Most attributes can be defined probabilistically - i.e., as distributions as opposed to single fixed values (as discussed in Section 4.6.3). When a simulation is run probabilistically, IMPACT completes a user-specified number of iterations (replications) of the simulation. Each successive iteration of a given simulation will complete calculations by selecting (based on the probability of occurrence) one of the possible input values of parameters that have been defined in a probabilistic manner within the scenario. Accordingly, the output from probabilistic simulations consists of a range of values produced during each iteration. The output is described using several statistical quantities such as mean, maximum, minimum, and percentile. 3.3.12 Data Storage All the polygons, blocks, and attributes defined in a scenario are saved to a single IMPACT file. The default scenario is an “empty” scenario in that it contains no polygons or blocks. It is supplied as a template that can be used as a starting point for creating a new scenario. Once you start to create polygons and blocks, you should save the scenario under a new name. 3.4 Windows The IMPACT model uses a number of windows to provide access to different model components. The means of access, the contents, and the specific operational features of each of the available windows are described in detail in this section of the manual. 3.4.1 Biosphere Window Access The main window in IMPACT is the Biosphere Window. This window is the main window where the contents of a scenario are displayed. This window is opened whenever you create a new scenario or open an existing scenario. Simply click within the bounds of this window to bring it to the foreground or close all other IMPACT windows. The Biosphere window also contains the main menu bar and toolbar that are used to create and modify a scenario, including commands for creating and modifying polygons. It remains open at all times while IMPACT is running. MODEL FEATURES AND FUNCTIONS 3-7 Environmental IMPACT™ User Manual Summary of Functions: ? create or modify polygons ? link polygons ? use as a gateway to all other IMPACT windows ? print contents (in list, graphic, or map display mode) ? import or export graphic files Contents and Features The Main window contains seven menus and one toolbar. All windows that are available in IMPACT, and their associated commands. are accessible through the Biosphere window’s pull-down menu bar. Each menu contains commands that pertain to a certain type of function: ? File: commands for creating, opening, closing, saving and printing of scenarios; ? Edit: commands for copying and pasting objects; ? View: commands for changing how information is displayed in a window; ? Biosphere: commands for changing attributes of the Biosphere, such as scale, meteorology, etc. ? Polygon: commands for creating and changing attributes of Polygons; ? Simulate: commands for starting a simulation and controlling the type of simulation output desired; ? Info: commands for displaying the program version. The functions of the main toolbar (depicted below) are described in Section 3.5. The activation of toolbar commands result in changes in cursor appearance to help track the current command mode. This window is called Biosphere since it provides a visual depiction of the base components of the biosphere (i.e. land and water) and provides access to all attributes of the biosphere. All polygons that have been created for a scenario are displayed in this window. There are two ways of viewing contents of the Biosphere window: 1. Graphic mode; all polygons are drawn with their true outlines (as in graphic mode) superimposed on a background map image which the user can import as a graphics file of various formats (refer 3-8 MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual to Section 4.2 and 4.3.2). This is the default mode and is the one in which the user can interact with the Biosphere. In Graphic mode, the status panel in the bottom part of the window shows the current map scale, coordinates the cursor is over, and the current grid spacing. In the example shown above, the map scale is 1 : 67338, the cursor is over the point (UTM: 454757, 6330601; Lat: 57d7m6.236s, Long: -81d44m49.61s) and the biosphere boundaries are 11064 m by 12080 m. 2. List view mode; scenario contents are provided in text summary format within an expandable menu list, an example of which is provided below. List for is for review and presentation purposes only, and modifications of scenario content are not permitted. MODEL FEATURES AND FUNCTIONS 3-9 Environmental IMPACT™ User Manual Printing in graphic mode is accomplished by selecting the Print command from the File menu or by clicking the Print button ( ). The list view window contains its own print command button In the top left corner (see above). The total area occupied by any scenario is defined by the biosphere’s map boundary, which may be specified within the Scale dialogue (refer to Section 3.6.4). Depending on the map boundary and current scale, the usable area of the Biosphere window may be much larger than the area visible on screen. In this 3-10 MODEL FEATURES AND FUNCTIONS Environmental IMPACT™ User Manual case, you can use the scroll bars to move to different parts of the map or use the Zoom In and Zoom Out toolbar buttons to increase or decrease the scale at which polygons are drawn. The name of the scenario file that is currently open is shown in the Biosphere window’s title frame, located at the top-left of the window. In the example provided above, the file name is Sample Scenario_540.SNR. This will change if you choose to save the file under a different name. 3.4.3 Polygon Contents Window Access While in the Biosphere window, the user can open any polygon’s Contents window by double-clicking on the polygon, or by selecting the polygon (single click) and choosing the Open polygon command from the Polygon pull-down menu. Summary of Functions ? create or modify blocks ? create aliases ? create links between blocks Contents and Features Each polygon appearing in the Biosphere window has its own associated window in which the contents of that polygon are displayed. The window’s name is set by default to “Land Polygon" or "Water Polygon", followed by "