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Groundwater Modeling System GMS v3.0 TUTORIALS

1. 17 12 17 13 1 Reading in the Original 1 17 12 17 13 2 Changing the cosine e a Es 17 12 17 13 3 Changing the Analysis 17 12 17 13 4 Editing the Material Properties s 17 13 1714 SAVING THE SIMULATION 17 13 17 15 2 E E es Bic E E E E E 17 14 17 16 VIEWING THE SOLUTION ara NE Ee EE seeteetveseseversenddeeveceedesetensevesssecnte 17 14 17 17 CONCLUSION EEEE EEEE EE E E S E EE E EE E 17 15 CHAPTER 1 Introduction This document contains tutorials for the Department of Defense Groundwater Modeling System GMS Each tutorial provides training on a specific component of GMS Since the GMS interface contains a large number of options and commands you are strongly encouraged to complete the tutorials before attempting to use GMS on a routine basis In addition to this document the GMS Reference Manual also describes the GMS interface Typically the most effective approach to learning GMS is to complete the tutorials before reading the reference manual 1 1 Suggested Order Of Completion In most cases the tutorials can be completed in any desired order However some of the tutorials are pre
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3. Y b Figure 6 5 Cell to be Selected on Bottom Layer Now that all of the wells have been defined we can go back to the top layer Select the Increment button twice in the Mini Grid Plot 6 12 Saving the Simulation Now we are ready to save the simulation and run MODFLOW 1 Select the Save As command in the MODFLOW menu 2 Move to the directory titled tutorialwnodfgrid 3 Change the file name to gridmod mfs 4 Select the Save button MODFLOW Grid Approach 6 15 6 13 Running MODFLOW We are now ready to run MODFLOW 1 Select the Run MODFLOW command from the MODFLOW menu 2 Select the OK button At this point MODFLOW is launched in a new window The super file name is passed to MODFLOW as a command line argument MODFLOW opens the file and begins the simulation As the simulation proceeds you should see some text output in the window reporting the solution progress When the solution is finished close the window and return to GMS 6 14 Viewing the Solution We are now ready to view the solution 1 Select the Read Solution command from the MODFLOW menu 2 Select the OK button At this point you should see a set of head contours for the top layer 6 14 1 Changing Layers To view the solution on the middle layer Select the Decrement button in the Mini Grid Plot To view the solution on the bottom layer Select the Decrement but
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5. for the project name Select the Save button By saving the project we have save all of the data associated with the exercise including the 2D mesh feature objects etc This also saves the FEMWATER simulation to a set of files named femmod It is also possible to save the FEMWATER simulation without saving the rest of the files using the Save Save As commands in FEMWATER menu This approach is used to save multiple version of the FEMWATER simulation without having to save unneeded copies of the rest of the project files 15 20 GMS Tutorials To run FEMWATER 1 Select the Run FEMWATER command from the FEMWATER menu 2 Select OK at the prompt The FEMWATER window should appear and you will see some information on the progress of the model convergence The model should converge in a few minutes When the model converges close the window and return to GMS 15 12 Viewing the Solution Next we will read in the computed solution and view it 1 Select the Read Solution command from the FEMWATER menu 2 Select OK at the prompt 15 12 1 Viewing Fringes First we will view a color fringe plot 1 Select the Display Options command in the Display menu 2 Turn on the Fringes option 3 Select the FEMWATER tab 4 Turn off the Head and Flux options 5 Select the OK button z 6 Switch to oblique view 7 Select the Shade macro Og 15 12 2 Viewing a Water Table Iso Surface A better way to view the sol
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7. The grid approach to MODFLOW pre processing is described in this tutorial In most cases the conceptual model approach is more efficient than the grid approach However the grid approach is useful for simple problems or academic exercises where cell by cell editing is necessary It is not necessary to complete this tutorial before beginning the MODFLOW Conceptual Model Approach tutorial 6 1 Description of Problem The problem we will be solving in this tutorial is shown in Figure 6 1 This problem is a modified version of the sample problem described near the end of the MODFLOW Reference Manual Three aquifers will be simulated using three layers in the computational grid The grid covers a square region measuring 75000 ft by 75000 ft The grid will consist of 15 rows and 15 columns each cell measuring 5000 ft by 5000 ft in plan view For simplicity the elevation of the top and bottom of each layer will be flat The hydraulic conductivity values shown are for the horizontal direction We will use values equal to one fifth of these amounts for the vertical direction 6 2 GMS Tutorials Flow into the system is due to infiltration from precipitation and will be defined as recharge in the input Flow out of the system is due to buried drain tubes discharging wells not shown on the diagram and a lake which is represented by a constant head boundary on the left Starting heads will be set equal to zero and a steady state solution will be
8. 1 Select the Select Arc Groups tool Model Calibration 14 9 Double click on any of the river arcs Turn on the Observed flux option Select the Options button In the Observed Values section enter a value of 167000 for the Steady state flux rate In the Confidence interval section enter a value of 7500 for the Interval The values we entered indicate that to achieve calibration the computed flux should be between 159500 and 174500 ft day 167000 7500 1 2 Select the OK button twice to exit both dialogs Click outside the arc group to unselect it At this point you should see a calibration target appear for the observed flux on the arc group 14 9 Generating Error Plots Next we will generate some plots related to the calibration error We will create two plots related to error at the observation points 1 Select the Observation Wells coverage from the Coverages combo box at the top of the GMS screen Select the Obs Plot Options command from the Display menu Select the New button Leave the type as Computed vs observed this should be the default Select the New button again Change the type to Error Summary Select the OK button Select the Show Plot Window command from the Display menu ak Select the Frame Image macro A F 14 10 GMS Tutorials 14 9 1 Computed vs Observed Plot 14 9 2 In the first plot a symbol is drawn for each of the observation points A poi
9. 3 Inthe Coverage Type section select the Observation option 4 Select the Options button 5 Select the New button 6 Change the name to concentration 7 Select the OK button to exit the Observation Coverage Options dialog 8 Select the OK button to exit the Coverages dialog Next we will create an observation point 1 Select the Create Point tool 2 Click on a point somewhere in the grid downgradient of the NAPL source The final step is to create a time series plot 1 With the point still selected select the Obs Plot Options command in the Display menu 2 Select the New button to create a new plot 11 16 GMS Tutorials 3 Change the type of the plot to Time series 4 Select the OK button 5 Select the Show Plot Window command in the Display menu 11 17 1 Moving the Observation Point At this point you should see a plot of the active data set vs time The plot can easily be changed to display the variation in the data set at a different location 1 Select the Select Points Nodes tool ie 2 Click on the observation point and drag it to a new location Note you may need to reposition or resize the Plot Window to see the observation point 11 17 2 Plotting Multiple Data Sets By default only the active data set is plotted For SEAM3D solutions it is often useful to include multiple species in the plot This can be accomplished as follows 1 Select the Obs Plot Options command in the Disp
10. 8 15 Viewing the Solution To view the results from the second simulation 1 Select the Read Solution command from the MODPATH menu 2 Select the OK button Now you should see a set of pathlines starting at the landfill and terminating in the well the creek bed and in the river at the bottom of the model You may wish to view this solution in cross section view as well 8 16 Conclusion This concludes the MODPATH tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt 9 MT3DMS Grid Approach This tutorial describes how to perform an MT3DMS simulation within GMS An MT3DMS model can be constructed in GMS using one of two approaches the conceptual model approach or the grid approach With the conceptual model approach the sources sinks and zones in the model are defined with GIS objects and automatically assigned to the grid With the grid approach values are manually assigned to the grid While the conceptual model approach is generally preferable for large complicated models simple models can be easily constructed using the grid approach The grid approach is described in this tutorial The following tutorial describes the conceptual model approach 9 1 Description of Problem The problem to be solved in this tutorial is shown in Figure 14 1 This problem corresponds to the sixth sample problem Two Dimensional Transport in a Heterogeneous
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12. OE OEE OI REE ETRE 2 1 2 2 REQUIRED MODULES INTERFACES cccccccsccccsessssscesecececsesseaececececsenseaeeecececeeeaaeeeeeeecsensaesesecscsesentsaeeeeecs 2 1 2 3 IMPORTING VERTICES E E E sein be oud Sets 2 2 DA STRIANGULATING i555 he he a eas Bn LA ee 2 3 DEG WCONTOWURING Se Nak A 2 3 2 0 SHADING E EE 2 3 PIT A EDITING A A E AAE E EE A A E E AA E AE E E A 2 4 2 8 DRAGGING a a e E A EA R E 2 4 2 9 DRAGGING IN OBLIQUE VIEW reor E EES A EE RE TEE EErEE ETS RE 2 5 2110 USING THE EDIT WINDOW a a s a a a 2 5 2 11 TZOCKING VERTICES E E 2 5 2 12 ADDING VERTICES E 2 6 2 13 DELETING VERTICES EEE EEE E EEE EA E E E EE 2 6 2 F4 SMOOTHING A TEIN enee eea de aeea eR S ER 2 7 2 14 1 Deleting the TIN EEE EEE EA TENEKE AE E ATES 2 7 2 14 2 Copying the a AK REOS s ES AREN EETA eR o i AE SaS 2 8 2 14 3 S bdividing the TIN a eeka 2 8 2 14 4 Bei oid hes aah coi fas gas es i A E 2 8 2 14 5 Deleting the Scatter Point 2 9 2 15 READING ANOTHER TIN ae Ern EAEE n ER nn 2 9 2 16 CHANGING THE ACTIVE T
13. THE BCP PAORA E baeticeat vauiee seta cadaa dotnet Ga te Saga E ANIA 6 7 0 81 Layer TY Des aE EE Eae 6 7 6 86 27 Layer Parameters ok S SE SE Sco a ON en 6 7 6 8 3 Top Layer 6 8 viii GMS Tutorials 684 Middle Layer cironi ea a te o oa e o 6 8 Oeo LG Ver se 6 8 6 97 THE RECHARGE PACKAGE E EAI AVE ES RRE S AEN 6 9 6 10 THE DRAN PACKAGE E E EERE REEE E RE E EEEO EEEE EEA E EE E RERE 6 9 6 10 1 Selecting the Cells nee a Ge ae a ee a Hie cde e a 6 9 6 10 2 Assioningeth e Drains ne cdots 6 10 6 10 3 Assigning the Drain Elevations 6 11 WELL PACKAGE S 6 11 11 1 Top Layer WES O Ea ERa re EEEO i EE 6 11 6 11 2 Middle Layer Well Sierran a E ta uses events E Une Caves E EE EAEE ES 6 12 6 11 3 Bottom Layer a a A E R OE ARNE ARS 6 13 6 127 SAVING THE SIMULATION Er ETA ET EEE E ERREA E EA EEE Ter E 6 14 6 13 RUNNING MODFLOW cento E a E A E E et ee edo 6 15 6 14 VIEWING THE SOLUTION a aa e eorr E a aaee en EE EOE E Ona e Cea e e SEESE 6 15 6 14 1 Changing LAVers oeieo i a E aN
14. 3 For Face 1 change the number in the NZ field to 2 Do the same for Face 3 2 and 4 4 Select the OK button A set of particles should appear around the perimeter of the cell To restore the display wk 1 Select the Frame macro A F 2 Select the up arrow to return to layer one 8 8 Specifying the Tracking Direction The last step in setting up the MODPATH data is to specify the tracking direction Since we want to delineate the capture zone for the well we will perform backward tracking and track the particles upgradient 1 Select the General Options command from the MODPATH menu 2 At the top of the dialog select the Backward option 3 Select the OK button 8 9 Saving the Simulation We are now ready to save the simulation and MODPATH 1 Select the Save As command from the MODPATH menu 2 In the Save File dialog locate and open the directory entitled tutorial nodpath 3 Enter pathI rsp for the file name 4 Select the Save button 8 10 Running MODPATH We are now ready to run MODPATH To launch MODPATH 1 Select the Run MODPATH command from the MODPATH menu 2 Select the OK button 8 6 GMS Tutorials At this point MODPATH is launched in a new window The response file name is passed to MODPATH as a command line argument MODPATH opens the file and begins the simulation As the simulation proceeds you should see some text output in the window reporting the solution progress When the
15. 4 Select the OK button to exit the Packages dialog 5 Select the Close button to exit the Basic Transport Package dialog 10 17 2 Entering the Sorption and Biodegradation Data Next we will enter the sorption and biodegradation data in the Chemical Reactions Package dialog 1 Select the Chemical Reaction Package command in the MT3D menu 2 Inthe Sorption section select the Linear isotherm option 3 In the Kinetic rate reaction section select the First order irreversible kinetic reaction option MT3DMS Conceptual Model Approach 10 11 4 In the lower part of the dialog enter the following values Bulk density 104 0 1st sorption constant 1st order rate constant dissolved phase 1st order rate constant sorbed phase 5 In both the middle and the bottom portion of the dialog switch the layer to layer 2 and enter the following values Bulk density 100 0 1st sorption constant 1st order rate constant dissolved phase 1st order rate constant sorbed phase 0 00005 6 Select the OK button to exit the dialog 10 18 Saving the Simulation We are now ready to save the new simulation 1 Select the Save As command in the MT3D menu 2 Enter run2 mts for the file name 3 Select the Save button 10 19 Running MT3DMS Using the same steps you followed above execute MT3DMS and compute a solution with the run2 mts super file 10 20 Viewing the Solution To view the results from the second sim
16. 5 Enter 15000 0 for the End value 6 Select the Cap above option 7 Select the Display values option 8 Select the OK button 9 Once the images are generated use the playback options to view the film loop 10 After viewing the film loop select the Stop a button to stop the animation 11 Select the Done button to exit the Film Loop dialog 5 19 Deleting the Grid and Scatter Point Data To delete all data currently in memory 1 Select the New command in the File menu 2 Select No to confirm the deletion 5 20 Conclusion This concludes the Three Dimensional Geostatistics tutorial If you were originally running in normal mode and switched to demo mode to complete this tutorial you can switch back to normal mode as follows 1 Select the Normal Mode command from the File menu 2 Select the OK button at the prompt If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 6 MODFLOW Grid Approach Two approaches can be used to construct a MODFLOW simulation in GMS the grid approach and the conceptual model approach The grid approach involves working directly with the 3D grid and applying sources sinks and other model parameters on a cell by cell basis The conceptual model approach involves using the GIS tools in the Map module to develop a conceptual model of the site being modeled The data in the conceptual model are then copied to the grid
17. 6 Click on the OK button 16 6 GMS Tutorials 16 4 4 A new node should appear between nodes D and E Repeat this process to create new nodes in the following locations 1 Create 4 intervals 3 nodes between nodes C and D 2 Create 4 intervals 3 nodes between nodes E and G 3 Create 6 intervals 5 nodes between nodes and F 4 Create 4 intervals 3 nodes between nodes F and H 5 Create 10 intervals 9 nodes between nodes A and I At this point your nodes should resemble the nodes shown in Figure 16 4 Figure 16 4 Nodes After Interpolating Intermediate Nodes Creating an Extra Node 16 4 5 At this point we are almost ready to create elements but we first need to add one more node to ensure that the sheet pile is properly represented in the mesh To do this we need to add one more node slightly to the right of the node labeled P in Figure 16 4 To create the node 1 Choose the Create Node tool 2 Click anywhere just to the right of node P 3 Enter 90 25 32 0 in the x and y fields in the Edit Window and hit the Enter key Creating the Elements We are now ready to create some elements Although there are several ways to create elements in this case the easiest thing to do is triangulate the nodes that we have created In most cases however quadrilateral elements are more efficient than triangular elements We can create a mesh composed primarily 16 4 6 20 Confined 16 7 of quadr
18. 7 8 Defining the Hydraulic Conductivity Next we will enter the hydraulic conductivity for each layer In many cases you may wish to define multiple polygons defining hydraulic conductivity zones For the sake of simplicity we will use a constant value for each layer 7 8 1 Layer First we will assign a K value for the top layer 1 2 In the Coverage combo box select the Layer 1 coverage From the Feature Objects menu select the Build Polygons command and select OK at the prompt Double click on the polygon Select the Horizonal K option and enter a value of 16 Select the Vertical K option and enter a value of 4 Select the OK button 7 8 2 Bottom Layer For the bottom layer 1 2 In the Coverage combo box select the Layer 2 coverage From the Feature Objects menu select the Build Polygons command and select OK at the prompt Double click on the polygon 4 5 6 MODFLOW Conceptual Model Approach 7 17 Select the Horizonal K option and enter a value of 32 Select the Vertical K option and enter a value of 8 Select the OK button This completes the definition of the coverages in the conceptual model Before continuing to create the grid we will make the sources sinks coverage the active coverage In the Coverage combo box select the Sources Sinks coverage 7 9 Locating the Grid Frame Now that the coverages are complete we are ready to create the grid The firs
19. However the default value of zero is correct Thus we are finished with this package Select the OK button to exit the Biodegradation Package dialog 11 13 Saving and Running the Simulation At this point we are ready to save the model and run SEAM3D 1 Select the Save As command from the MT3D menu 2 In the Save File dialog locate and open the directory entitled tutorial seam3d 3 Enter run for the filename 4 Select the Save button to save the files To run SEAM3D 1 Select the Run SEAM3D command from MT3D menu 2 Select OK at the prompt 3 When the simulation is finished return to GMS 11 14 GMS Tutorials 11 14 Reading the Solution Now we will read in the solution for post processing 1 Select the Read Solution command from the MT3D menu 2 Select OK at the prompt 11 15 Setting the Contouring Options We will now turn on color shaded contours and set up a color legend 1 Select the Contour Options command in the Data menu 2 Turn on the Color fill between contours option 3 Select the Color Ramp Options button 4 Turn on the Show color legend option 5 Select the OK button twice to exit both dialogs 11 16 Viewing the Concentration Contours First we will view the conservative tracer solution at 2000 days 1 Select the Tracer Conservative data set in the Data Set combo box at the top of the GMS window 2 Select the time step at t 2000 days from the TS combo box at the top of the
20. Select No at the prompt CHAPTER 14 Model Calibration An important part of any groundwater modeling exercise is the model calibration process In order for a groundwater model to be used in any type of predictive role it must be demonstrated that the model can successfully simulate observed aquifer behavior Calibration is a process wherein certain parameters of the model such as recharge and hydraulic conductivity are altered in a systematic fashion and the model is repeatedly run until the computed solution matches field observed values within an acceptable level of accuracy GMS contains a suite of tools to assist in the model calibration process These tools are described in this tutorial The model calibration exercise in this tutorial is based on the MODFLOW model Thus you may wish to complete the MODFLOW Conceptual Model Approach tutorial prior to beginning this tutorial Although this particular exercise is based on MODFLOW the calibration tools in GMS are designed in a general purpose fashion and can be used with any model 14 1 Description of Problem A groundwater model for a medium sized basin is shown in Figure 14 1 The basin encompasses 28 square miles It is in a semi arid climate with average annual precipitation of 1 25 ft yr Most of this precipitation is lost through evapotranspiration The recharge which reaches the aquifer eventually drains into a small stream at the center of the basin This stream drains to th
21. Switch to the Borehole module 2 Select Open command from File menu 3 Locate and open the directory entitled tutorialsolids 4 Select the file entitled holes gpr 5 Click on the Open button You should now see a 3D view of the borehole logs Each of the colors represents a different type of soil The green soil is a clean sand the red soil is a silty sand and the blue soil is a silty clayey fine sand For the remainder of this tutorial the soils will be referred to by their colors for simplicity 3 5 Changing the Z Scale In some cases it is useful to magnify the display in the z dimension so that the variation in the stratigraphy depicted by the borehole logs is more apparent To change the z scale 1 Select the Z Magnification command from the View menu 2 Enter a value of 2 0 3 Select the OK button The holes should now appear stretched in the vertical direction 3 6 Displaying the Hole Names To help distinguish between the holes on the screen throughout the remainder of the tutorial the names of the holes will be posted on the holes 1 Select the Display Options macro 2 Turn Hole Names option 3 Select OK button The names of the holes should appear at the tops of the holes These names were defined in the borehole file 3 4 GMS Tutorials 3 7 Creating an Extrapolation Polygon 3 7 1 3 7 2 The next step in the construction of the stratigraphy model is to create
22. conductance data for each layer For our problem we have three layers The top layer is unconfined and the bottom two layers are confined Since this is the default we don t need to make any changes to the layer types Layer Parameters The buttons in the lower right portion of the dialog are for entering the parameters necessary for computing the cell to cell conductances 6 8 GMS Tutorials 6 8 3 6 8 4 6 8 5 MODFLOW requires a set of parameters for each layer depending on the layer type The parameters include transmissivity and leakance that are a function of the layer thicknesses By default GMS uses the true layer approach for defining layer data The user enters the top and bottom elevation and the vertical and horizontal hydraulic conductivity for each layer When the data are written to the MODFLOW file GMS automatically computes the required parameters for each layer Top Layer First we will enter the data for the top layer 1 Select the Top Elevation button 2 Select the Constant gt Layer button 3 Enter a value of 200 4 Select the OK button 5 Select the OK button to exit the Top Elevation dialog Repeat this process to enter the following values for the top layer Parameter Value Bottom Elevation 150 ft Horizontal Hydraulic Conductivity 50 ft d Vertical Hydraulic Conductivity 5 ft d Middle Layer Next we will enter the data for the middle la
23. that you complete the first SEEP2D tutorial the previous chapter before doing this tutorial 17 1 Description of Problem The problem we will be solving in this tutorial is shown in Figure 17 1 The problem consists of an earth dam with anisotropic soil and a low permeability core in the interior 17 2 GMS Tutorials Core kx 150 ft yr ky 60 ft yr Shell kx 75 ft yr ky 30 ft yr Figure 17 1 Unconfined Flow Problem 17 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 17 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 2D Mesh module H H e The Map module e The SEEP2D interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 17 4 Creating the Mesh The first step in defining the model is to create the finite element mesh The mesh will be constructed using the Map gt 2D Mesh comma
24. 0 01 5 Select the OK button Selecting Output Control Next we will select the output options We will choose to output a pressure head file only 1 Select the Output Control command from the FEMWATER menu 2 Turn off the Save nodal moisture content file and Save velocity file options 3 Select the OK button 15 8 4 Defining the Fluid Properties Finally we will define the fluid properties Select the Fluid Properties command from the FEMWATER menu The items in this dialog are dependent on the units we have selected Since this is a steady state solution we can ignore the viscosity and compressibility options 15 16 GMS Tutorials 1 Enter 1 94 for the Density of water 2 Enter 2 4037e11 for the Acceleration of gravity 3 Select the OK button 15 9 Defining Initial Conditions 15 9 1 Because of the non linear equations used by FEMWATER to model flow in the unsaturated zone FEMWATER is more sensitive to initial conditions than saturated flow models such as MODFLOW If a set of initial conditions is defined that is significantly different than the final head distribution FEMWATER may be slow or even unable to converge For a flow simulation FEMWATER requires a set of pressure heads as an initial condition The FEMWATER interface in GMS includes a command that can be used to automatically create a set of pressure heads from a user defined water table surface The water table surface is defined by a set o
25. 0 1 11 12 GMS Tutorials 11 12 3 Generation Coefficients To enter the generation coefficient for H2S 1 Select the Gen Coeffs tab 2 Enter 0 15 in the Production generation coeff edit field 11 12 4 Use Coefficients To enter the electron acceptor use coefficients 1 Select the Use Coeffs tab in the dialog 2 Select each item in the list at the upper left and enter the following values for the Elec acceptor use coeff O2 Benzene 3 0 O2 Toluene 3 2 SO4 Benzene 8 0 SO4 Toluene 8 2 11 12 5 Saturation Constants To enter the saturation constants 1 Select the Sat Const tab 2 Select each item in the first list and enter the following values for the Hydro half sat const O2 Benzene 1 0 O2 Toluene 2 0 SO4 Benzene 1 0 SO04 Toluene 2 0 3 Select each item in the second list and enter the following values for the Elec acc half sat const 02 0 1 504 0 5 SEAM3D 11 13 11 12 6 Rates To enter the rate data 1 Select the Rates tab 2 Make sure that in the Death Rate portion of the dialog that the Calculated by model option is selected 3 Select each item in the second list and enter the following values for the Max specific rate of substrate utilization O2 Benzene 0 5 O2 Toluene 0 05 SO4 Benzene 0 005 04 Toluene 0 0 11 12 7 Starting Concentrations At this point the only remaining data for the Biodegradation package are the starting concentrations for the microcolonies
26. 12 3 The scatter points can be imported from a tabular scatter point file For regions with complex stratigraphy such as embedded seams or outcroppings the scatter point data must be defined carefully Once interpolated the scatter point data may result in overlapping layers These errors can be automatically corrected using the Model Checker 12 5 Sample Problems To illustrate the process of defining the scatter point data importing the data interpolating the elevations and fixing errors we will look at a series of example problems Each example problem illustrates a different problem and describes a simple approach for correctly modeling the stratigraphy 12 6 Building the Grid Before discussing the sample problems we will first define a grid The grid will be rectangular in shape and have three layers To build the grid 1 Switch to the 3D Grid module 2 Select the Create Grid command from the Grid menu 3 Enter the following values X Dimension Y Dimension Z Dimension Origin 500 500 0 Length 2500 1500 600 Cells 50 30 3 4 Select the OK button At this point a grid should appear To view the layers Select the View I Axis macro 7 Notice that the layers are flat When a grid is first constructed GMS assumes a constant layer thickness To return to top view 27 Select the View Axis macro 12 7 Case 1 Complete Layers The first case we will e
27. 7 lt Observed Interval lt Computed Value Error 4 Calibration Target lt Observed Value lt Observed Interval Figure 143 Calibration Target Point Statistics We can view more detailed statistics concerning the error at the point by selecting the point 1 Select the Select Points Nodes tool ie 2 Click on the observation point Notice that a set of statistics related to the point is displayed in the Help Bar at the bottom of the GMS screen 14 7 Reading in a Set of Observation Points 14 7 1 Using the steps defined above we could proceed to enter the remaining nine observation points However in the interest of time we will simply read in a previously prepared map file containing all ten points Deleting the Current Coverage Before reading in the observation points we will first delete the current coverage 1 Select the Coverages command from the Feature Objects menu 2 Make sure the Observation Wells coverage is selected 3 Select the Delete button 4 Select OK at the prompt 5 Select the OK button 14 8 GMS Tutorials 14 7 2 Reading in the Points Using the steps defined above a point was created for each of the observation wells The coverage containing these points was saved to a map file We will now read in that file 1 Select the Open command from the File menu 2 Select No at the prompt to indicate we dont wish to save the project 3 Change the file filter to ma
28. A hybrid layer requires top elevation bottom elevation and K For all but the bottom layer an array of leakance values is required Further if the model is transient one or two arrays or storage coefficients are required Many of the layer arrays transmissivity leakance and confined storage coefficient are a function of the layer geometry Setting up such arrays for input can be quite tedious However GMS provides a way to automate these calculations The layer data can be entered in one of two modes the direct approach where the user directly enters the arrays described above or the true layer method With the true layer method the user provides the top and bottom elevation of each layer and the horizontal and vertical hydraulic conductivity and all required arrays are computed by GMS as the MODFLOW input files are written out to disk prior to running MODFLOW This is the default method used by GMS and all examples described in this tutorial are based on this approach Using the true layer method also makes it possible to view the stratigraphy when in side view Interpolating to MODFLOW Layers With the true layer method the main task involved in setting up the layer data is to interpolate the top and bottom layer elevations from a set of scatter points The interpolation can be performed directly to the MODFLOW arrays using the to MODFLOW Layers command in the Interpolation menu in the 2D Scatter Point module Defining Layer Data
29. Enter run2 mfs for the file name 4 Select the Save button 14 12 2 Running MODFLOW To run MODFLOW 1 Select the Run MODFLOW command from the MODFLOW menu 2 Select OK at the prompt When the MODFLOW simulation is completed close the MODFLOW window and return to GMS 14 13 Reading in the Solution Next we will read in the MODFLOW solution and view the error associated with the new solution 1 Select the Read Solution command from the MODFLOW menu 2 Select the OK button Note that the plots in the Plot Window have been updated All three error norms are lower Up to this point we have not paid much attention to our flux target on the arc group In the next section we will create a plot that shows how well the flux target is being met Note that although the error improved for the observation wells the head is still too low on the left and right sides of the model Model Calibration 14 13 14 14 Error vs Simulation Plot When performing trial and error calibration it is important to keep track of the trend in the error as new solutions are repeatedly computed GMS provides a special calibration plot to simplify this task We will make such a plot for both the flux and observation wells 1 Switch to the Map module 2 Select the Obs Plot Options command in the Display menu 3 Select the Plot 2 item in the list on the left 4 Select the Delete button 5 Select the New button 6 Change the Plot typ
30. Enter topgreen for the name of the TIN 5 Select the OK button A green TIN should appear Note that once again the TIN is automatically extended to the extrapolation polygon and in addition the TIN is automatically extended to a point halfway between the holes that were selected and the holes that were not selected Of course this boundary could be edited but it provides a reasonable initial estimate of the extent of the surface defined by the selected contacts For the purposes of this tutorial we will accept the default surface 3 9 3 Hiding the TIN To hide the TIN 1 Switch to the TIN module 66 2 Choose the Select TINs 68 tool 3 Select the TIN you just created by clicking on its icon es 4 Select the Hide macro ii 5 Switch back to the Borehole module 3 10 Constructing the Red Soil TIN Next we will construct the TIN representing the top of the red soil unit at the lower part of the stratigraphy Stratigraphy Modeling With Solids 3 9 3 10 1 Constructing the TIN To construct the TIN 1 2 3 8 9 Choose the Select Contacts tool 46 Select the blue red contact on hole 4G Select the Auto Select command from the Boreholes menu Turn off the Match material above option Select the OK button Select the Contacts gt TIN command from the Boreholes menu Select the Auto extrapolate only option Select the OK button Enter topred for the name of the TIN 10 Select the OK
31. For the purposes of this tutorial the TIN is adequate as is and will not be edited Hiding the TIN Before continuing it is useful to hide the TIN so that it will not be cluttering the display while the other TINs are being constructed To hide the TIN 1 Switch to the TIN module 2 Choose the Select TINs T tool 3 Select the TIN you just created by clicking on its icon Les 4 Select the Hide macro i 5 Switch back to the Borehole module 3 9 Constructing the Green Seam 3 9 1 Next we will construct the TIN representing the top of the green seam that cuts through the side To select the contacts 1 Choose the Select Contacts tool 2 Select the blue green contact on hole 3G Automatically Selecting Contacts We could now select the remaining contacts one at a time with the Shift key down as we did last time However this time we will use the Auto Select command to select the remaining holes The Auto Select command is used to select a set of contacts that match a previously selected contact 1 Select the Auto Select command from the Boreholes menu 3 8 GMS Tutorials 2 Select the OK button 3 9 2 Creating the TIN All of the contacts at the top of the green soil should now be selected To construct the TIN 1 Select the Contacts gt TIN command from the Borehole menu 2 Select the Auto extrapolate with trimming to selected boreholes option 3 Select the OK button 4
32. Selecting an Interpolation Scheme The next step is to select an interpolation scheme Several interpolation schemes are supported in GMS because there is no one interpolation scheme that is superior in all situations Typically the best approach is to try several schemes and then determine which scheme is giving the most reasonable results GMS has been structured in such a way that several different schemes can be tested quickly and easily 4 7 Linear Interpolation First we will try simple linear interpolation 1 Select the Interp Options command from the Interpolation menu 2 Select the Linear option 3 Select the OK button To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter linear for the name of the new data set 3 Select the OK button Two Dimensional Geostatistics 4 5 4 8 Contouring the Grid The concentrations have been interpolated to the grid but we must first set the appropriate display options before we can see the resulting contours 1 Switch to the 2D Grid module FE 2 Select the Display Options macro 3 Turn Contours and Fringes options 4 Turn off the Nodes option 5 Select the OK button A set of contours should now be displayed 4 9 Mapping Elevations It is often useful to display the grid in oblique view Select the Oblique View macro Note that the grid is flat When we created the grid we assigned a z value of 0 0 to all
33. a E E ested 11 12 21124 USE Coefficients nnne iune p ai e n Giese A Sine betes heed E S 11 12 11 12 5 Saturation Constants r enn E T EE E Ae 11 12 AER EEE EA E EA A 11 13 112257 Starting eo Eoee a e iSe etae A aE reS ip apa 11 13 11 13 SAVING AND RUNNING THE 51 11 13 11 14 READING THE SOLUTION E 11 14 11 15 SETTING THE CONTOURING OPTIONS viros ii tryer 11 14 11 16 VIEWING THE CONCENTRATION CONTOURS 11 14 11 17 SETTING UP A TIME SERIES PLOT 11 15 11 17 1 Moving the Observation 11 16 11 17 2 Plotting Multiple Data Sets si c ccccssisesscssasesseseaessecacsevtsessssessncasnsoopsasascgeisnssessaceabesesgeateseaenes 11 16 11 18 OTHER VIEWING OPTIONS E ERR E 11 17 T119 CONCLUSION aie 11 17 12 DEFINING LAYER DATA vssscssssssosansessasendssnnssssecsasntsssenscennseneseoseessecasendesenssedeassseniconnssedtsesensssosasnasesests 12 1 12 1 GETTING STARTED E R ES E 12 1 12 2 REQUIRED MODULES INTERFACES ccccsessscececececeessnaececececsensaaececececseuaececceecsess
34. a pumping rate of 100 000 However for this well change the edit fields at the bottom of the dialog so that the well is applied to layer two change both the edit fields to 2 Grid Refinement A well represents a point of convergence in the groundwater flow and causes steep gradients in the head near the well In order to accurately model the flow near wells the grid is typically refined in the vicinity of the wells This type of refinement can be performed automatically in GMS by assigning refinement data directly to the wells in the conceptual model 1 Select the Select Points Nodes tool ie 2 Select both wells by clicking on the wells while holding the Shift key 7 14 GMS Tutorials 3 Select the Attributes command in the Feature Objects menu 4 Select the Refine Point button 5 Select the Refine grid in X direction option and enter a value of 75 0 for the Base cell size and a value of 500 0 for the Max cell size 6 Select the Refine grid in Y direction option and enter a value of 75 0 for the Base cell size and a value of 500 0 for the Max cell size 7 Select the OK button twice to exit both dialogs 7 7 Delineating the Recharge Zones 7 7 1 The next step in constructing the conceptual model is to construct the coverage which defines the recharge zones We will assume that the recharge over the area being modeled is uniform except for the landfill The recharge in the area of the landfill will be reduced due to
35. altered since the default boundary type is no flow However we need to mark the stream arc and the coastline arc as constant head arcs 1 Select the Select Arcs tool 2 While holding down the Shift key click on both the stream arc and on the coastline arc 3 Select the Attributes command in the Feature Objects menu 4 Turn on the Head fluid flux option 5 Select the OK button Note that no head values were assigned to the arcs The head values are assigned to the nodes at the ends of the arc This allows the head to vary linearly along the length of the arc For the coastline arc the head at both ends is the same Since the default head value is zero no changes need to be made However we do need to enter a head value for the upper end of the stream The head will vary linearly along the stream from the specified value at the top to zero at the coast 1 Select the Select Points Nodes tool ie 2 Double click on the node at the top left end of the stream arc 3 Enter a value of 200 for the head 4 Select the OK button 15 4 7 Building the Polygon Now that the arcs are defined we are ready to build a polygon defining the model domain The polygon is necessary for two reasons 1 it is used to define the model domain when the mesh is generated and 2 it is used to assign the recharge In many cases the model domain is subdivided into 15 6 GMS Tutorials 15 4 8 multiple recharge zones each defined by a po
36. arcs on the rivers as specified head arcs 1 Select the Select Ares 001 2 Select the arcs on the south and east sides of the model by selecting one arc and holding down the Shift key while selecting the other arc 3 Select the Attributes command in the Feature Objects menu 4 Select the Specified Head type 5 At the bottom of the dialog change the second edit field to 2 so that the head boundary applies to both layers 6 Select the OK button 7 Click anywhere on the model other than on the arcs to unselect them Note that the color of the arcs has changed indicating the type of the arc 7 10 GMS Tutorials 7 6 5 The next step is to define the head at the nodes at the ends of the arcs The head along a specified head arc is assumed to vary linearly along the length of the arc 3 4 Select the Select Points Nodes tool Double click on the node on the west left end of the arc the southern bottom boundary Enter a constant value for head of 697 0 Select the OK button In a similar fashion assign a value of 685 0 to the node at the junction of the two rivers and a value of 703 0 to the node at the top of the arc on the east boundary of the model Defining the Drain Arcs At this point we will enter the arcs at the locations of the creek beds to define the drains Select the Create Arc tool Create the arc labeled as arc 1 in Figure 7 5 Start by clicking on the bottom a
37. at specified times option Select the Times button Select the Initialize Values button Enter the following values Initial time step size 300 Bias 1 0 Maximum time step size 300 Maximum simulation time 3000 Select the OK or Close buttons three times to return to the Basic Transport Package dialog 10 5 5 Selecting the Packages Next we will specify which of the MT3DMS packages we intend to use 1 2 3 Select the Packages button Select the Advection package the Dispersion package and the Source Sink Mixing package options Select the OK button Note that the Basic Transport Package dialog also includes some layer data We will enter the data for these arrays at a latter point in the tutorial MT3DMS Conceptual Model Approach 10 5 Select the Close button to exit the Basic Transport Package dialog 10 6 Assigning the Aquifer Properties 10 6 1 MT3DMS requires that a porosity and dispersion coefficient be defined for each of the cells in the grid While these values can be assigned directly to the cells it is sometimes convenient to assign the parameters using polygonal zones defined in the conceptual model The parameters are converted to the grid cells using the Map gt MT3DMS command Assigning the Parameters to the Polygons To assign the porosities and dispersion coefficients to the polygons 1 2 6 7 H Switch to the Map Module In the Coverages combo box at the top
38. button 3 10 2 Hiding the TIN To hide the TIN 1 Switch to the TIN module o Choose the Select TINs tool T Select the TIN you just created by clicking on its icon Select the Hide macro Switch back to the Borehole module i 3 11 Constructing the Blue Seam TINs Most of the boreholes show a thin region of blue soil near the bottom of the holes We will model this region as a blue seam which cuts diagonally through the site This seam will lie entirely within the red soil To model the seam we will need to construct two TINs one at the top of the seam and one at the bottom 3 10 GMS Tutorials 3 11 1 Constructing the Top TIN To construct the TIN at the top of the seam 1 2 3 Choose the Select Contacts tool Be Select the red blue contact on hole 8G see Figure 3 2 Select the Auto Select command from the Boreholes menu Select the OK button Select the Contacts gt TIN command from the Boreholes menu Select the Auto extrapolate with trimming to selected boreholes option Select the OK button Enter topblue2 for the name of the TIN Select the OK button Select this contact Figure 3 2 Contact on Hole 8G to be Selected 3 11 2 Constructing the Bottom TIN To construct the TIN at the bottom of the seam Stratigraphy Modeling With Solids 3 11 1 Since the Auto Select command will not work in this case hold down the Shift key and select the following contact
39. button 4 In the Data Set combo box at the top of the window select the pressure_head item 5 Select the Contour Options command in the Data menu 6 Inthe Contour Interval section select the Specified values option 7 Select the Values button to the right of the Specified values option SEEP2D Unconfined 17 15 8 Enter a value of 0 0 for the first contour value 9 Select the OK button 10 Select the OK button The displayed line corresponds to the boundary between the saturated and unsaturated zones 17 17 Conclusion This concludes the SEEP2D tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt
40. button 5 8 Displaying lso surfaces Now that we have interpolated to the nodes of the 3D grid there are several ways to visualize the contaminant plume One of the most effective ways is to use iso surfaces Iso surfaces are the three dimensional equivalent of contour lines An iso surface represents a surface of a constant value contaminant concentration in this case To define and display iso surfaces 1 Switch to the 3D Grid module 2 Select the Display Options macro 3 Turn off the Cells option and turn on Grid shell Fringes and Iso surfaces options 4 Select the Options button to the right of the Jso Surfaces option 5 In the first edit field in the list of values type 3000 0 6 Turn on the Cap option between values 1 amp 2 7 Select the OK button to exit the so Surface Options dialog 8 Select the OK button to exit the Display Options dialog You should now see a wireframe representation of the iso surface To generate a shaded image 1 Select the Shading Options command from the Display menu 2 Select the Hidden surface option and turn on the following options Use light source Smooth features and Overlay edges 5 6 5 9 GMS Tutorials 3 Select the OK button 4 Select the Shade macro Og A color shaded plot of the iso surface should appear on the screen Interior Edge Removal A series of edges are draped over the iso surface plot These edges represent the intersection of the
41. by dragging a box that encloses all of the arcs 3 Select the Redistribute Vertices command from the Feature Objects menu 4 Select the Target spacing option 5 Enter a value of 4 0 for the spacing 6 Select the OK button 17 4 6 Creating the Polygons Now we are ready to create the polygons defining the two material zones Simply creating the arcs does not create the polygons We must explicitly create the polygons using the arcs 1 Select the Build Polygons command from the Feature Objects menu 2 Select OK at the prompt 17 4 7 Assigning the Material Types Now that the polygons are created we need to define a material type to be associated with each polygon 1 Choose the Select Polygons tool 2 Double click anywhere inside the polygon representing the shell of the dam 3 Notice that material 1 has been assigned to the shell by default Change the name of the material to Shell 4 Select the OK button SEEP2D Unconfined 17 7 Now we will do the same for the other polygon 1 Double click anywhere inside the polygon representing the core of the dam 2 Select the New button to create a new material 3 Change the name of the material to Core 4 Select the OK button 17 4 8 Constructing the Mesh At this point we are ready to construct the mesh 1 Select the Map gt 2D Mesh command from the Feature Objects menu 2 Select OK at the prompt As the mesh is being constructed you should see some
42. components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 10 4 Importing the Project The first step is to import the East Texas project This will read in the MODFLOW model and solution the background image and all other files associated with the model To import the project 1 Select the Open command from the File menu 2 Locate and open the directory entitled tutoriaNmodfmap sample 3 Select the file entitled sample gpr 4 Choose the Open button MT3DMS Conceptual Model Approach 10 3 10 5 Initializing the MT3DMS Simulation 10 5 1 10 5 2 10 5 3 Now that the MODFLOW model is in memory we can initialize the MT3DMS simulation First we will initialize the model 1 Switch to the 3D Grid module 2 Select the New Simulation command from the MT3D menu 3 Select the Basic Transport Package command from the MT3D menu Defining the Units First we will define the units We will not change the length and time units these must be consistent with the flow model However we need to define units for mass and concentration 1 Select the Units button 2 Sele
43. define inconsistent or incompatible options and parameters Such errors will either cause MODFLOW to crash or to generate an erroneous solution The purpose of the Model Checker is to analyze the input data 7 24 GMS Tutorials currently defined for a MODFLOW simulation and report any obvious errors or potential problems Running the Model Checker successfully does not guarantee that a solution will be correct It simply serves as an initial check on the input data and can save a considerable amount of time that would otherwise be lost tracking down input errors To run the Model Checker 1 Select the Check Simulation command in the MODFLOW menu 2 Select the Run Check button A list of messages are shown for each of the MODFLOW input packages If you have done everything correctly there should be no errors for any of the packages but perhaps a few warnings When there is a warning or an error the Model Checker helps fix the problems If you select or highlight one of the errors in the error list a list of suggested steps for fixing the problem appears in the window at the bottom of the Model Checker When appropriate it also selects the cells or layers associated with the problem The Model Checker can be left on the desktop while the steps are followed to fix the problem The Model Checker operates differently than most other dialogs in GMS It acts as modeless dialog This means that you do not have to exit the dialog to continue
44. holding down the Shift key select the solid entitled blue2 Select the Set Operations command from the Solids menu In the section entitled Operand 1 turn on the Delete option This will delete the old version of the red solid once the set operation is completed since we won need it anymore 3 14 GMS Tutorials _ 7 Select the minus operation 8 Enter red for the name of the new solid resulting from the set operation 9 Select the OK button The red solid now has a hole in it at the location of the blue seam To confirm Select the Shade macro Og To revert to wireframe view Select the Refresh macro ef 3 15 Constructing the Green Solid Next we will construct the solid representing the green seam This solid will be created by filling between the green TIN and the red TIN 1 Switch to the TIN module oo 2 Select the Select TINs tool de 3 Select the TIN entitled topgreen 4 While holding the Shift key select the TIN entitled topred 5 Select the Fill Between TINs gt Solid command from the Build TIN menu 6 Enter green for the name of the solid 7 Select the OK button 3 16 Constructing the Top Blue Solid Finally we will construct the solid representing the top blue soil layer This solid is bounded below by both the green solid and the red solid However it can still be constructed using the Fill Between TINs gt Solid command The solid is constructed by filling fro
45. messages in the lower left corner of the window The mesh construction should take several seconds 17 5 Renumbering the Mesh The next step in the mesh construction process is to renumber the nodes and elements The motivation behind the renumbering process and some tools for viewing node and element numbering are described in the previous tutorial and in the GMS Reference Manual To renumber the nodes and elements we must first select a string of nodes on the boundary This string of nodes defines a starting point for the renumbering process In the case of a simple earth dam the numbering is typically optimal if the renumbering begins at the leftmost or rightmost node in the mesh Therefore in this case the string of nodes for renumbering will consist of only one node 1 Switch to the 2D Mesh module 8 2 Choose the Select Node Strings tool rd 3 Select the leftmost node in the mesh point A in Figure 17 3 4 Select the Renumber command from the Modify Mesh menu 17 8 GMS Tutorials 17 6 Initializing the SEEP2D Solution Now that the mesh is constructed we can begin to enter the SEEP2D data Select the New Simulation command in the SEEP2D menu 17 7 Setting the Analysis Options Next we will enter the analysis options We will select the option to deform the mesh to the phreatic surface This will model flow in the saturated zone only 1 2 Select the Analysis Options command from SEEP2D menu Enter S
46. of the GMS window select the Layer I coverage Choose the Select Polygons tool Double click on the layer polygon Turn on the Aquifer Porosity option and enter a value of 0 3 Turn on the Longitudinal dispersivity option and enter a value 20 Select the OK button To assign the values to layer 2 1 In the Coverages combo box at the top of the GMS window select the Layer 2 coverage Double click on the layer polygon Turn on the Aquifer Porosity option and enter a value of 0 4 Turn on the Longitudinal dispersivity option and enter a value 20 Select the OK button Click anywhere outside the model to unselect the highlighted polygon 10 6 GMS Tutorials 10 7 Assigning the Recharge Concentration The purpose of our model is to simulate the transport of contaminants emitted from the landfill When the flow model was constructed a separate reduced value of recharge was assigned to the landfill site This recharge represents leachate from the landfill We will assign a concentration to this recharge The concentration can be assigned directly to the recharge polygon in the conceptual model 1 In the Coverages combo box at the top of the GMS window select the Recharge coverage 2 Double click on the landfill polygon 3 For the Contaminant concentration in the Recharge section at the top right of the dialog enter a constant value of 20000 0 for the concentration 4 Select the OK button 5 Click anywhere o
47. of the grid nodes To make the variation in concentrations easier to visualize we can use the Map Elevations command to load the concentration data set values into the z coordinates of the grid nodes 1 Select the Map Elevations command from the Data menu 2 Select the data set entitled linear 3 Choose the OK button 4 10 Shading the Grid Color shading and hidden surface removal can be applied to provide an even more effective display of the grid Select the Shade macro Og Notice that the nodes in the outer part of the grid still all have a concentration value equal to zero When linear interpolation is performed the scatter points are triangulated to form a temporary TIN A plane equation is computed for 4 6 GMS Tutorials each triangle in the TIN and the coefficients of the plane equation are used to interpolate to points inside the triangle Therefore linear interpolation cannot be performed for grid nodes outside the convex hull of the TIN the boundary of the TIN As a result these nodes are assigned a value of zero However for this application a value of zero is appropriate since the concentrations of the scatter points on the perimeter of the scatter point set are zero 4 11 Clough Tocher Interpolation Next we will try Clough Tocher interpolation 1 Switch to the 2D Scatter Point module E 2 Select the Interp Options command from the Interpolation menu 3 Select the Clough Tocher option 4 Select th
48. package MT3DMS Grid Approach 9 5 3 In the Solver section select the Strongly Impl Proc SIP option 4 Select the OK button to exit the Packages dialog The IBOUND Array The next step is to set up the IBOUND array The IBOUND array is used to designate each cell as either active IBOUND3 gt 0 inactive IBOUND 0 or constant head IBOUND lt 0 For our problem all cells will be active except for the top and bottom rows which will be designated as constant head The default value for the IBOUND array is active thus all we need to do is change the IBOUND value for the top and bottom rows to a value less than zero 1 This could be accomplished with the IBOUND array editor that is accessed through the IBOUND button but in this case it is easier to select the cells in the Graphics Window and assign a value using the Cell Attributes dialog 1 Select the Close button to exit the Basic Package dialog 2 Choose the Select i tool in the Tool Palette 3 Click anywhere in the top row to select it 4 While holding down the Shift key click anywhere in the bottom row 5 Select the Cell Attributes command in the MODFLOW menu 6 Enter a value of 1 for the BOUND value 7 Select the OK button 8 Click outside the grid to unselect the cells The Starting Head Array The next step is to set up the Starting Heads array The Starting Heads array is used to establish an initial head value that MODFLOW will modify in an it
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50. requisites for other tutorials For example since TINs are used in the construction of solid models the Surface Modeling With TINs tutorial Chapter 2 should be completed before the Stratigraphy Modeling With Solids tutorial Chapter 3 1 2 RT3D Tutorials This document contains all of the tutorials for GMS except for the RT3D tutorials Due to the large number of RT3D tutorials one for each reaction package they are contained in a separate document 1 2 1 3 GMS Tutorials Demo vs Normal Mode The interface for GMS is divided into ten modules Some of the modules contain interfaces to models such as MODFLOW Such interfaces typically contained within a single menu Since some users may not require all of the modules or model interfaces provided in GMS modules and model interfaces can be licensed individually Modules and interfaces that have been licensed are enabled using the Register command in the File menu The icons for the unlicensed modules or the menus for model interfaces are dimmed and cannot be accessed GMS provides two modes of operation demo and normal In normal mode the modules and interfaces you have licensed are undimmed and fully functional and the items you have not licensed are dimmed and inaccessible In demo mode all modules and interfaces are undimmed and functional regardless of which items have been licensed However all of the print and save commands are disabled While some of the tutori
51. side of the model This type of layer is more difficult to model with MODFLOW since a full array of K values must be defined for each layer Making the cells in the second layer inactive on the right side of the model will not work since this will result in a no flow boundary between the first and third layers To model the seam correctly we will use a three layer model and the second layer will extend throughout the entire model domain However we will adjust the layer thickness of the second layer so that the cells will be very small on the right side of the model thus simulating the pinchout Figure 12 3 Typical East West Cross Section Through Site with Embedded Seam Importing the Scatter Points Next we will import the scatter points for Case 2 The scatter point file is formatted as shown above in Figure 12 2 However the elevations for the second layer on the right side of the model are adjusted so that the bottom of layer 2 is ABOVE the top of layer 2 This overlap will be fixed after the values are interpolated Before importing the new points we will delete the old points While it is possible to have multiple scatter points sets in memory at once we will delete the first set since we are finished with the points 1 Switch to the 2D Scatter Point module E 12 8 2 12 8 3 Defining Layer Data 12 7 2 Select the Delete All command from the Edit menu 3 Select OK at the prompt To imp
52. solution is finished close the window and return to GMS 8 11 Viewing the Solution 8 11 1 To view the computed pathlines 1 Select the Read Solution command from the MODPATH menu 2 Select the OK button You should see a set of pathlines which converge on the east well Notice that the pathlines intersect the area covered by the proposed landfill indicating a potential for leachate from the landfill to appear in the water pumped from the well Viewing the Pathlines in Cross Section View The 3D nature of the pathlines is best seen in cross section view 1 Select a cell near the right landfill 2 Select the View J Axis macro ci You may wish to move back and forth through the columns When finished Select the View Axis macro 8 12 Tracking Particles from the Landfill 8 12 1 Next we will perform a second particle tracking simulation This time we will perform forward tracking from a set of starting locations which coincide with the site of the proposed landfill Changing the Tracking Direction First we will change the tracking direction to forward 1 Select the General Options command from the MODPATH menu 2 At the top of the dialog select the Forward option MODPATH 8 7 3 Select the OK button 8 12 2 Deleting the Starting Locations Next we will delete the starting locations that we created around the well 1 Select the Select Starting Locations tool 2 Select the particle
53. the Open button 5 Select OK at the prompt 17 13 2 Changing the Mesh Display Next we will turn on the display of the nodes and elements 1 Select the Display Options command in the Display menu 2 Turn on the Nodes and Elements options 3 Select the OK button 17 13 3 Changing the Analysis Options Next we will change the analysis options Two methods are provided in SEEP2D for computing the relative conductivity in the unsaturated zone the linear front method and the Van Genuchten method With the linear front method the relative conductivity varies linearly from the saturated value down SEEP2D Unconfined 17 13 to a user specified minimum at a given negative pressure head With the Van Genuchten method the Van Genuchten parameters are used to define the variation of the relative conductivity in the unsaturated zone Both methods are described in detail in the SEEP2D Primer We will use the linear front option 1 Select the Analysis Options command from the SEEP2D menu 2 Enter Sample Unconfined Problem Part II for the title 3 Inthe Unconfined section select the Saturated unsaturated with linear front option 4 Select the OK button 17 13 4 Editing the Material Properties Next we need to define a minimum relative conductivity and a threshold pressure head for each material 1 Select the Material Properties command from the SEEP2D menu 2 Select the material entitled Shell 3 Enter a valu
54. the Shade macro Og As can be seen there is now much more correlation in the horizontal direction 5 8 GMS Tutorials 5 12 IDW Interpolation With Gradient Planes As discussed in the Two Dimensional Geostatistics tutorial IDW interpolation can often be improved by defining higher order nodal functions at the scatter points The same is true in three dimensions Next we will try IDW interpolation with gradient plane nodal functions 1 2 4 5 Select the Interp Options command from the Interpolation menu Select the Options button to the right of the Inverse distance weighted option In the Nodal function section at the top of the dialog select the Gradient plane option Select the OK button to exit the IDW Interpolation Options dialog Select the Close button to exit the Interpolation Options dialog To interpolate to the grid 1 2 Select the to 3D Grid command from the Interpolation menu Enter idw_gp for the name of the new data set Select the OK button Select the Shade macro Og 5 13 IDW Interpolation With Quadratic Functions Next we will try DW interpolation with quadratic nodal functions 1 2 Select the Interp Options command from the Interpolation menu Select the Options button to the right of the Inverse distance weighted option In the Nodal function section at the top of the dialog select the Quadratic option In the section entitled Computation of nodal fun
55. the conceptual model approach where the data are entered via points arcs and polygons The previous tutorial described how to use the grid approach This tutorial describes how to use the conceptual model approach 10 1 Description of Problem The problem we will be solving for this tutorial is an extension of the problem described in the tutorial entitled MODFLOW Conceptual Model Approach Thus if you have not yet completed the MODFLOW tutorial you may wish to do so now before continuing In the MODFLOW tutorial a site in East Texas was modeled We will be using the solution from this model as the flow field for the transport simulation The model included a proposed landfill For this tutorial we will be performing two transport simulations to analyze the long term potential for migration of leachate from the landfill In the first simulation we will be modeling transport due to advection only In the second simulation we will include sorption and decay in addition to advection 10 2 GMS Tutorials 10 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 10 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module H e The Map module e The MT3DMS interface You can confirm whether each of these
56. the material called Lower Aquifer 6 Select the OK button 15 6 Hiding Objects Before continuing we will unclutter the display by hiding the objects we are finished with We will hide everything but the feature objects and the 3D mesh To hide the TINs 1 Drag a box around all three TIN icons 2 Select the Hide macro We can also hide the scatter points 1 Switch to the 2D Scatter Point module E 2 Select the Select Scatter Point Sets tool ee 3 Drag a box around both scatter point set icons 4 Select the Hide tool A To hide the 2D mesh 1 Switch to the 2D Mesh module Ht 2 Select the Display Options command in the Display menu 3 Turn off the Nodes and Elements options 4 Select the OK button To unclutter the display of the 3D mesh 1 Switch to the 3D Mesh module ttt 2 Select the Display Options command 15 14 GMS Tutorials 3 Turn off the Nodes option 4 Select the OK button Finally to view a shaded image of the mesh Select the Shade macro Og 15 7 Converting the Conceptual Model Now we are ready to convert the conceptual model to the 3D mesh model This will assign all of the boundary conditions using the data defined on the feature objects 1 Select the New Simulation command in the FEMWATER menu this initializes the data structures for the FEMWATER simulation H 2 Switch to the Map module 3 Select gt FEMWATER command in the Feature Objects menu 4 Sel
57. the nodal half band width 1 Select the Get Info command from the File menu 2 Note the Max node half band width 3 Select the OK button The id s of each of the nodes in the mesh can be displayed as follows 1 Select the Display Options command from the Display menu 2 Select the Node numbers option 3 Select the OK button At this point you may wish to use the Zoom tool to zoom in and examine the node numbering When you are finished select the Frame Image macro ak A F To renumber the nodes and elements we must first select a string of nodes on the boundary This string of nodes defines a starting point for the renumbering process 1 Choose the Select Node String tool MIE 2 Select the leftmost column of nodes in sequence from top to bottom This can be done one of two ways a Click on the top node then the next node down and so on until all of the nodes in the column have been selected Or b Click on the top node in the column and while holding down the Control key click on the bottom node in the column All of the intermediate nodes will automatically be selected 3 Select the Renumber command from the Modify Mesh menu 16 10 GMS Tutorials Notice how the node numbering has changed Bring up the Get Info dialog again to examine the new nodal half band width Generally the best node half band width occurs when a sequence of renumbering nodes is selected along the minor axis of the mesh Wh
58. the solids and make them invisible 1 Select the Select Solids tool from the Tool Palette 2 Choose the Select All command from the Edit menu E 3 Select the Hide macro from the Tool Palette z 4 Select the Oblique View macro from the Tool Palette 3 18 3 Deleting the Boreholes Since we no longer need the boreholes we can remove them from the display by simply deleting them 1 Switch to the Boreholes module A 2 Select the Delete All command from the Edit menu 3 Select OK to confirm the deletion Stratigraphy Modeling With Solids 3 17 3 18 4 Deleting the Polygon We will also delete the polygon H 1 Switch to the Map module 2 Select the Delete All command from the Edit menu 3 Select OK to confirm the deletion 3 18 5 Shading the Cross Sections Once again the cross sections are displayed as a wire frame image by default We can shade the cross sections the same way we shaded the solids Select the Shade macro Og from the Tool Palette You may wish to use the Rotate tool to rotate the cross sections to a better viewing position and shade the solids again 3 19 Layer Boundaries Notice that the boundaries of the green seam and the blue seam have an abrupt vertical edge rather than a gradually narrowing pinchout boundary which would seem more natural A sharp pinchout at the boundary can be achieved by altering the coordinates of the TIN vertices prior to constructin
59. to fit in this case because of the zero values described above 4 Select the OK button to exit the Variogram Editor 5 Select the Close button to exit the Kriging Options dialog 6 Select the Close button to exit the 2D Interpolation Options dialog 4 17 3 Interpolating to the Grid To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter krig for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og 4 18 Switching Data Sets Now that we have interpolated to the grid using several different interpolation schemes we may wish to review the results by replotting some of the interpolated data sets We can switch back to one of the previous data sets using the combo boxes at the top of the GMS window 1 Switch to the 2D Grid module 2 Inthe combo box titled Data Set select the linear item Notice that the contours of the grid have changed but the elevations still correspond to the previous data set kriging To change the elevations to the Two Dimensional Geostatistics 4 13 new data set we must select the Map Elevations command as explained earlier However in this case we will simply view the plot in plan view 4 Select the Plan View macro tex We can display a color shaded plot in plan view by changing the contouring options 1 Select the Display Options macro E 2 Turn off the Cells option and turn on the Grid boundary option 3 Sel
60. to enter the extrapolation polygon The extrapolation polygon is entered using the feature object tools in the Map module First we will create a single arc defining a closed loop around the site H 1 Switch to the Map module 2 Select the Create Arc tool d 3 Create a single arc by clicking on the points shown in Figure 3 1 clockwise or counter clockwise it does not matter To ensure you are placing the points in the proper location note the cursor coordinates displayed on the left side of the Edit Window Begin with the point 50 700 To close the polygon double click on the point you started with 50 700 250 700 2 7G 5 600 400 6 3G 50 50 600 50 Figure 3 1 The Coordinates of the Points Defining the Extrapolation Polygon 3 7 4 Creating the Polygon Now that we have created the arc we must use the arc to build a polygon 1 Select the Build Polygons command from the Feature Objects menu 2 Select OK at the prompt to use all arcs 3 6 GMS Tutorials The Build Polygons command traverses the set of currently defined arcs and makes polygons out of all of the closed loops found This is trivial in this case since there is only one arc and one closed loop 3 7 5 Turning off the Drawing Grid Now that the polygon is entered you can turn off the drawing grid 1 Select the Drawin
61. to select the New command from the File menu to ensure the program settings are restored to the default state 2 2 Required Modules Interfaces This tutorial can be completed in either demo mode or normal model If you are already in demo mode you may continue with the tutorial If you are in normal mode you will need to ensure that the necessary components have 2 2 2 3 GMS Tutorials been licensed This tutorial utilizes the following components of the GMS interface e The TIN module The 2D Scatter Point module You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If each of these items is enabled you can proceed to complete the tutorial in normal mode If not you will need to switch to demo mode before continuing To switch to demo mode 1 Select the Demo Mode command from the File menu 2 Select OK at the prompts Importing Vertices To begin reviewing the tools available for TIN modeling we will first import a set of vertices from a text file These vertices are simply a set of xyz points entered into a TIN file The TIN file format is described in the GMS File Format document To import the vertices 1 If necessary switch to the TIN module ao 2 Select the Open command from the File menu 3 At the bottom of the Open dialog select the tin filter 4 In the Read File dialog locate and open the directory ent
62. transverse disp to long disp parameter 2 Enter a value of 0 2 for the Ratio of vert disp to long disp parameter 3 Ensure that the value of the Effective molecular diff coefficient is Zero 4 Select the up arrow at the top of the dialog to switch to layer 2 5 Once again enter 0 2 for both dispersivity ratios 6 Select the OK button to exit the Dispersion Package dialog 10 12 The Source Sink Mixing Package Dialog Finally we must define the data for the source sink mixing package However the only data required in this package for our simulation are the concentrations assigned to the recharge from the landfill These values were automatically assigned to the appropriate cells from the conceptual model Thus the input data for this package are complete 10 8 GMS Tutorials 10 13 Saving the Simulation We are now finished inputting the MT3DMS data and we are ready to save the model and run the simulation To save the simulation 1 Select the Save As command from the MT3D menu 2 Locate and open the directory entitled tutorialnt3dmap 3 Enter runl mts for the file name 4 Select the Save button to save the files 10 14 Running MT3DMS To run MT3DMS 1 Select the Run MT3DMS command from the MT3D menu 2 Select OK at the prompt 3 When the simulation is finished close the window and return to GMS 10 15 Viewing the Solution We will now go back to GMS to view the solution computed by MT3DMS 1 Se
63. type to MODF MT3D MODP Select the OK button Note that we did not delete the recharge and hydraulic conductivity coverages We will use these coverages to construct our local model The boundaries of the coverages are larger than they need to be but that does not matter 13 6 2 Creating the Boundary Arcs Next we will create the boundary arcs First we need to zoom in on the local site model 1 Select the Zoom tool 2 Drag box around the local site boundary the red rectangle 13 6 GMS Tutorials 13 6 3 Create the boundaries as follows 1 Select the Create Arc tool M 2 Create four arcs two parallel to the contours and two perpendicular to the contours as shown in Figure 13 2 Double click on the corners to end each arc Figure 13 2 Arcs to be Created on Boundary of Local Model Building the Polygon Next we will use the arcs to build a polygon defining the model domain 1 Select the Build Polygons command from the Feature Object menu 2 Confirm that we want to use all of the arcs by selecting the OK button We need to be sure that the polygon is assigned to both grid layers 1 Choose the Select Polygons tool 2 Double click on the polygon 3 Change the layer assignment to go from layer 1 to 2 4 Select the OK button Regional To Local Model Conversion 13 7 13 6 4 Marking the Specified Head Arcs Th
64. we will create a coverage for the recharge polygons 1 2 3 4 5 Finally 1 Select the Copy command Change the name of the new coverage to Recharge Select the Options button Change the Coverage type to MODF MT3D areal attributes Select the OK button IMPORTANT STEP Select the Sources Sinks coverage so that it will be the active coverage when exiting the dialog All editing is done to the active coverage Select the OK button to exit the Coverages dialog Defining the Specified Head Arcs The next step is to define the specified head boundary along the south and east sides of the model Before doing this however we must first split the arc we just created into three arcs One arc will define the no flow boundary along the top and the other two arcs will define the two rivers An arc is split by selecting one or more vertices on the arc and converting the vertices to nodes 1 Select the Select Vertices tool PE MODFLOW Conceptual Model Approach 7 9 2 Select the two vertices shown in Figure 7 4 Vertex 1 is located at the junction of the two rivers Vertex 2 is located at the top of the river on the east side of the model To select both vertices at once select the first vertex and then hold down the Shift key while selecting the other vertex 3 Select the Vertices lt gt Nodes command in the Feature Objects menu Now that we have defined the three arcs we will specify the two
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66. 05 210 13 2120 1850 580 475 350 260 14 1980 1200 575 455 330 250 15 2100 950 580 465 350 255 16 2530 1720 565 490 370 335 17 2710 1020 550 480 390 350 18 2610 560 555 490 385 345 19 3090 1590 515 450 385 350 20 3040 790 5125 4475 3825 347 5 21 3050 420 512 5 4475 3825 347 5 22 495 1250 450 345 200 100 Figure 122 Tabular Scatter Point File for Case 1 The next step is to import the scatter point file The file has been given an extension of sp2 This identifies the file to GMS as a tabular scatter point file To import the file 12 7 2 12 7 3 Defining Layer Data 12 5 1 Select the Jnport command from the File menu 2 At the bottom of the Open dialog select the sp2 filter 3 Locate and open the file entitled tutoriaNayerdata casel sp2 Interpolating the Elevation Values You should see a set of points appear on the screen This new scatter point set has four data sets topl bot1 bot2 and bot3 The next step 15 to interpolate each of these data sets to the appropriate layer in the MODFLOW array Before interpolating the points we need to initialize the MODFLOW data Select the New Simulation command from the MODFLOW menu By default the top layer is unconfined and the underlying layers are all classified as confined If the water table is expected to drop below the bottom of the top layer the underlying layers should be designated as hybrid confined unconfined layers For simplicity we will use the
67. 3 4 Locate the cell with I 24 and J 16 and select it Select the Point Sources Sinks command in the MODFLOW menu In the Well section select the Add button Enter a value of 1633 0 for the flow rate note 0 0189m s X 3600s hr X 24hr d 1633 0m d Select the OK button 9 4 6 Saving the Simulation We are now ready to save the simulation and MODFLOW 1 2 Select the Save As command from the MODFLOW menu In the Save dialog locate and open the directory entitled tutoriaNmt3dgrid Enter flow mfs for the file name Select the Save button 9 4 7 Running MODFLOW To MODFLOW 1 Select the Run MODFLOW command from the MODFLOW menu 2 Select OK at the prompt 3 When the simulation is finished close the window and return to GMS 9 4 8 Viewing the Flow Solution Next we will read in the computed head values for the flow model MT3DMS Grid Approach 9 9 1 Select the Read Solution command from the MODFLOW menu 2 Select OK button 9 5 Building the Transport Model 9 5 1 Now that the flow solution has been computed we are ready to set up the MT3DMS transport simulation Like MODFLOW MT3DMS is structured in a modular fashion and uses a series of packages as input Consequently the GMS interface to MT3DMS is similar to the interface to MODFLOW and we will follow a similar sequence of steps to enter the input data Initializing the Simulation 9 5 2 First we will initi
68. 3D grid for the local scale model Regional To Local Model Conversion 13 3 4 Interpolate the heads and layer data values from the scatter points to the MODFLOW layer arrays for the local scale model Each of these steps will be described in more detail below 13 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 13 2 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 2D Grid module EA e The 3D Grid module e 2D Scatter Point module E H e The Map module e The MODFLOW interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 13 3 Reading in the Regional Model The first step in the model conversion process is to build a regional model Since the focus of this tutorial is primarily on the conversion process we will read in a previously constructed model 1 Select the Open command from the File
69. 4 11 4 17 2 Creating the Model a 4 11 Table of Contents vii 4 17 3 Interpolating tothe Grid ssis Weed od eE ea EOE E Ee 4 12 4 18 DATA e e a E E S E R 4 12 419 USING THE DATA CALCULATOR 2 AE EAT EARN ORN Weaseecsseececes 4 13 4 20 D 2 E 2A h INE IAN BLE DY N EE ET EEEE EE E E 4 14 4 21 EDINE D DN O a EET S E EA E E T E E ET EE EE WEE 4 14 SD GEOSTATISTIGS amp 5 1 Del lt GETPING STARTED 5 1 5 2 REQUIRED MODULES INTERFACES cccsccccccccsessssscecececeeseseaececececsesaaeeecccecsensaaeeeeceecsessaececeesesenenseaeeeeees 5 1 5 3 IMPORTING A SCATTER POINT SET ccscccccecccecsessscececececsesseaececececsessaececccscseseaeaeeececeesessaeseeceseneseaaeeeeees 5 2 5 4 DISPLAYING DATA COLORS rrn A tedeetap eae AA A egageauesssebeue Queeduesesedensenes 5 3 329 2 Z7MIAGNIFICA TION eR ES 5 3 5 6 CREATING A BOUNDING GRID cccecsessscccececsessnsccecececeesescaececececsesaaececcceceesaaeeececsesensaaeaesececseseneaeeeeecs 5 3 9 7 SIMPLE TD WINTER POLATION wiz 5250Sbencececk Sobbc hides dooce ook bi a ae 5 4 5 8 DISPLAYING ISO SURFACES 5 5 5 9 INTERIOR EDGE REMOVAL cccccccccsesessscecececeeseseaececececsescs
70. 8 5 8 10 RUNNING a seaceeceegesedatedbeadeseuaderatteteedeseueaudettedeesspousdeeeaseeesce 8 5 8 11 VIEWING THE S OLUTION AGERE N 8 6 8 11 1 Viewing the Pathlines in Cross Section 8 6 8 12 TRACKING PARTICLES FROM THE 8 6 8 12 1 Changing the Tracking 8 6 8 12 2 Deleting the Starting Locations 8 7 8 12 3 Defining the New Starting 8 7 8 13 SAVANG TAR SIMULATION 8 8 8 14 RUNNING MODPATH tetseesvtevecd R cevevsuestnatesdeoveegunsttetceveousebuved leaved spveeeededsedeses 8 8 8 15 VAEWING THE SOLUTION wan A ek TER BTA 8 8 8 16 CONGCEUSION E O E E 8 8 MT3DMS GRID APPROA CHivvcsarisssscssacssessnssnsssscoosnnssoansesasscosdeusecssessedendesenschinesteadeceasssossessoessesesessess 9 1 9 13 DESGCRIPTION OF PROBEEM d avnvesinetaccsdesendeecesueee 9 1 9 02 GETTING STARTED A 9 2 9 3 REQUIRED MODULES INTERFACES cccsccccccccsessssscecececeesesseseceeccecseaaeeecececeensaaeceeeceesensaaeaesecsesenenseaeeeeecs 9 2 9 4 BUILDING THE FLOW MODEL cccccessscecececeeseceececececsessnaececececsessaaecesececseseaassecececeesessaeeeeseeenensaasaeeees 9 3 DAD Creating the Grad irc icv
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72. Aquifer described in the MT3DMS documentation The problem consists of a low K zone inside a larger zone The sides of the region are no flow boundaries The top and bottom are constant head boundaries that cause the flow to move from the top to the bottom of the region An injection well with a specified concentration provides the source of the contaminants A pumping well serves to withdraw contaminated water migrating from the injection well A steady state flow solution will be computed and a transient transport simulation will be performed over a one year period 9 2 GMS Tutorials Constant head boundary H 250 m flow model No mass flux boundary transport model INJECTION WELL Q 0 001 m s C 57 87 ppm Hyd Cond 1 474x107m s LOW K ZONE No flow boundary PUMPING WELL flow model Q 0 0189 No mass flux boundary transport model No flow boundary flow model DY 2000 m No mass flux boundary transport mode Number of rows 40 Number of columns 32 Aquifer thickness 10 m K 1 474x10 m s Porosity 0 3 Longitudinal dispersivity 20 m Dispersivity ratio 0 2 Simulation time 1 0 yr DX 1600 m Constant head boundary H 36 25 m Figure 9 1 Sample Flow and Transport Problem 9 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings a
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74. GMS window This plot illustrates the concentration contours corresponding to no sorption and no reactions This is a useful benchmark to consider when viewing the other solutions To quickly switch between solutions we will use a shortcut 1 Click once and then click again on the Data Set combo box to highlight it 2 Select the down J arrow key on the keyboard to switch to the next lower solution in the list Note that once the edit field is highlighted you can use both the up and down arrow keys to quickly switch solutions The Home key takes you to the first data set in the list and the End key takes you to the last data set in the list SEAM3D 11 15 This plot non conservative tracer represents sorption but no reactions Use the down 4 arrow key to view the other solutions As you view the solutions note the relationship between the substrates and the electron acceptors You may wish to use the TS combo box to view the solution at different time steps 11 17 Setting up a Time Series Plot Another highly effective tool for viewing SEAM3D solutions is a time series plot A time series plot is used to display the variation of concentration vs time for one or more species at a particular point in the model Time series plots are set up using an observation coverage in the Map module First we will define an observation coverage 1 Switch to the Map module 2 Select the Coverages command in the Feature Objects menu
75. HE AQUIFER PROPERTIES ccccccsessscecececeesesececccecsensaecesecccseseaaesesececseseusaeseeeceesenseaeees 10 5 10 6 1 Assigning the Parameters to the amp 10 5 10 7 ASSIGNING THE RECHARGE CONCENTRATION sccscsscsssescsseeseesesssesscsesesessesesesecsuesscsesseesseeesssessasas 10 6 10 8 CONVERTING THE CONCEPTUAL 10 6 10 9 LAYER THICKNESSES sos bua E quateneds ies A eae AE O E E A ATAS EET 10 6 10 10 THE ADVECTION PACKAGE s miri sie ne EE EE EE E EREA EEE EEE ET E Ea 10 6 10 11 DISPERSION PACKAGE inienn nn a a E E a E 10 7 10 12 THE SOURCE SINK MIXING PACKAGE 10 7 10 13 SAVING THE SIMULATION AE EA R EA A 10 8 10 14 JRUNNINGIMT3B DMS EEE EEEE EE EE 10 8 10 15 VIEWING THE SOLUTION t eeii spoe 10 8 10 16 VIEWING A FEM LOOP npestudeebvnenss ueerdubdessvoren cgeseetcesevteynevesterceeenies 10 9 10 17 MODELING SORPTION AND DECAY ccccesceseccsesecssesseseeesessecssesecssesecsesesessesesesessuesscnesesesseseaeeesete 10 10 10 17 1 Turning the Chemical Reactions 10 10 10 17 2 Entering the Sorption and Biodegradation 10 10 10 18 SAVING THE SIMULATION
76. IN EEN A EEE E E S 2 10 2 17 HIDING AND SHOWING TINS a aa a a aa a a a aa a a aa aa e i enke Enas 2 10 218 10 E S A A T 2 10 DAD CONCLUSION a E r E a eae EEE ES 2 10 STRATIGRAPHY MODELING WITH SOLIDS scsssscsssscsssccsssscsssccssscssscssssssssscsssesssssssssessssses 3 1 Sel GETTING STARTED a EA EE E T E E EA 3 1 3 2 REQUIRED MODULES INTERFACES 3 1 3 3 CONSTRUCTING THE SOLID MODELS ccccssssscccececsessecececececsenssaeceecceceesssaeeecececeeseaeceeececeesenssaeeeeeeeenes 3 2 JA 7 Eana Aea e ENESE 3 2 3 5 CHANGING THE 29 dar onesies E A E S ETAN 3 3 3 60 DISPLAYING THE HOLE a A E E ENE REE TEES 3 3 3 7 CREATING AN EXTRAPOLATION POLYGON c c cccccccecsessscececececsesssaececececsesssaeceeeceesensaaeseeececeenenssseeeeeeeenes 3 4 IZI Setting Up the Views si ce ceases a Pe eS aM ak aed see A ea Ea 3 4 3 72 Tumming onthe Drawing de cesses eee teens A eine esate aes ete 3 4 3 7 3 Defining the Boundary ALC 3 5 3 74 Cheating the POISON 3 5 B73 TUNING Off th Drawing Grid ase eee 3 6 vi GMS Tutorials 3 8 CONSTRUCTING THE GROUND SURFACE
77. K The low K zone extends from x 200 to x 900 in the horizontal direction and from 1100 to y 1500 in the vertical direction This corresponds to a rectangular region with the cell 11 5 in the upper left corner and the cell 18 18 in the lower right corner To select the zone 1 Select the Select Cells tool 2 While examining the ijk display fields in the Edit Window select the cell with I 11 and 5 3 While holding down the Shift key select the cell with I 18 and J 18 4 Keep holding down the Shift key and drag a rectangle that just encloses the two cells you just selected To assign the k value 1 Select the Cell Attributes command in the MODFLOW menu 2 Enter a value of 0 0127 in the Horizontal Hyd Conductivity edit field note 1 474e 7m s X 3600s hr X 24hr d 0 0127m d 3 Select the OK button Defining the Wells Finally we will enter the data for the injection well and the pumping well First we will create the injection well The well is located at the cell 10 16 1 Locate the cell in I 10 and J 16 and select it by clicking in the cell 2 Select the Point Sources Sinks command in the MODFLOW menu 9 8 GMS Tutorials 5 In the Well section select the Add button Enter a value of 86 4 for the flow rate note 0 001m s X 3600s hr X 24hr d 86 4m d Select the OK button Next we will create the pumping well The well is located at the cell 24 16 1 2 6
78. THE DEPARTMENT OF DEFENSE Groundwater Modeling System GMS v3 0 TUTORIALS GMS 3 0 Tutorials Copyright 1999 Brigham Young University Environmental Modeling Research Laboratory All Rights Reserved Unauthorized duplication of the GMS software or user s manual is strictly prohibited THE BRIGHAM YOUNG UNIVERSITY ENVIRONMENTAL MODELING RESEARCH LABORATORY MAKES NO WARRANTIES EITHER EXPRESS OR IMPLIED REGARDING THE PROGRAM GMS AND ITS FITNESS FOR ANY PARTICULAR PURPOSE OR THE VALIDITY OF THE INFORMATION CONTAINED IN THIS USER S MANUAL The software GMS is a product of the Environmental Modeling Research Laboratory EMRL of Brigham Young University www emrl byu edu Last Revision December 13 1999 TABLE OF CONTENTS 1 INTRODUCTION issscitsctesescsdecstseessentdesasavesessnaseseecesvasenstescssesssesbcasseseacsseastbegsveneccsddavsvesceusascestovsscenssesseaes 1 1 1 1 SUGGESTED ORDER OF COMPLETION 1 1 1 2 RTBSD TUTORIALS oe Sup ee oh Saou Seb eae Gh Resse sag eae ch Sat ak Ga Rae Gh Seabee ae een 1 1 1 3 DEMO VS NORMAL MODE ccecesssssccecececeesssaececececsensnaececececeeneaaececececseneaaeeecececeeseaaeaetececeesenseaeeeeeeeees 1 2 SURFACE MODELING WITH TINS sssssccsssssscssccsevascesssvsesessonsssossssesaessncscesevesentescsvssasss nessensesetassosvonsess 2 1 DA lt GETPING
79. TING THE BLUE SEAM cccsccccccccesssssscecececsesenseaececeesesessnaececccecsesuaeceseeecsensaaeaesececsensaaaaeees 3 13 3 14 SUBTRACTING THE BLUE SEAM ccsscsccccececssssaececececsesseaececccecsessnaececececeessaaeaesececeeseeaeseeeceesensaaeees 3 13 3 15 CONSTRUCTING THE GREEN SOLID ioie erener ne rena eer EE EEEN E ESEN ENE SEEE EENE E aeai ES 3 14 3 16 CONSTRUCTING THE TOP BLUE SOLID noren eese ae a e a a ae E a ENEKE 3 14 JIZ NIEWING THE a a A E E N E E E E E 3 15 ea o EN E ELDRI EA NOIN AEE E Bes ee chet E A E EEA 3 15 3 18 1 Creating the Cross Se CHOMS 3 15 3 18 2 Hiding the edava daca EEE E EEN 3 16 3 18 3 Deleting the Borehole eaaeo 3 16 3 18 4 Deleting the POLY SOM sinin Ae a aE a 3 17 3 18 5 Skading the Cross Sections gossen ai ede eS A se eee 3 17 3 19 gt TEAYVER BOUNDARIES 3 17 3 20 DELETING THE SOLIDS AND TINS 3 17 3 21 GG ONCTIU STON 2065 3 17 4 2D GEOSTATISTICGS ENT s s EEEa a 4 1 4l GETTING STARTED 4 1 4 2 REQUIRED MODULES INTERFACES ccccccecsssssceceeeceeseseeecececeeseseeecececeesen
80. W DATA se ssesssesesessesessssesesesreneseesesesesreneseeseseseeresensesereseeernensesereseenese 7 18 7 13 CONVERTING THE CONCEPTUAL MODEL pEr e r ra e EE EE E s PREE REESEN Se 7 19 7 14 INTERPOLATNG LAYER ELEVATIONS sannio aneia ee 7 19 7 14 1 Importing the Ground Surface Scatter 7 20 7 14 2 Calculating a Starting Head Data 7 20 7 14 3 Interpolating the Heads and Elevations 7 21 7 14 4 Importing the Layer Elevation Scatter 7 21 Table of Contents ix 7 14 5 Interpolating the Layer 7 21 7 14 6 Adjusting the Display vies ove sens 7 22 7 14 7 Viewing the Model Cross 5 7 22 7 14 8 Fixing the Elevation Arrays eiennenn ani e oeeaaeaii 7 23 7 15 CHECKING THE SIMULATION sssesccssccocesssnscesecescessensceucesecesesnsceuecsecssesnsnacecsecscesnsnncesscesceessnnceseceese 7 23 TAG SSAVINGTHE PROJECT the cocoa ee 7 24 TAP RUNNING MO F O 7 25 7 18 VIEWING THE HEAD CONTOURS cccscccscceceesssseceeececeessseceeececeeseesececececseseaeceeseseseaaseeeececsensaaseeeess 7 25 7 19 VIEWING THE WATER TABLE IN SIDE 7 25 7 20 VIEWING THE FLOW BUDGET
81. W coverage type Select the OK button to return to the Coverages dialog Defining the Units At this point we can also define the units used in the conceptual model The units we choose will be applied to edit fields in the GMS interface to remind us of the proper units for each parameter 4 5 Select the Units button Enter ft for the length unit and d for the time unit We will ignore the other units they are not used for flow simulations Select the OK button Select OK again to exit the Coverages dialog Defining the Boundary The next step is to define the outer boundary of the model We will do this by creating an arc which forms a closed loop around the site 1 2 Select the Create Arc tool Begin arc by clicking once on the left west side of the model at the location shown in Figure 7 3 7 6 3 MODFLOW Conceptual Model Approach 7 7 3 Create the arc by proceeding around the boundary of the site in a counter clockwise direction and clicking on a sequence of points around the boundary Dont worry about the spacing or the exact location of the points just use enough points to define the approximate location of the boundary The boundary on the south and east sides of the model should coincide with the rivers The boundary along the top should coincide to the limestone outcropping as shown in Figure 7 3 4 Double click on the point where you began to end the arc Note As you are c
82. When the solution is finished close the window and return to GMS 16 12 Viewing the Solution To read the solution 1 Select the Read Solution command from the SEEP2D menu 2 Select the OK button You should see the solution as a flow net The flow net consists of equipotential lines total head contours and flow lines You can turn on the display of the total flow through the cross section as follows 1 Select the Display Options command from the Display menu 2 Select the SEEP2D tab 3 Turn on the Title and Total flow rate options 4 Select the OK button 16 13 Conclusion This concludes the SEEP2D tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 17 SEEP2D Unconfined SEEP2D can be used for both confined and unconfined problems The steps involved in performing a SEEP2D simulation for the unconfined condition are described in this tutorial Two approaches are available for unconfined problems with SEEP2D With the first approach the solution is only computed in the saturated zone and the mesh is truncated to the phreatic surface The computed solution then consists of a new mesh geometry file and a solution file with the heads With the second approach the mesh is not deformed and the flow in both the saturated and unsaturated zones is computed Both approaches will be illustrated in this tutorial It is recommended but not required
83. X2 rectangular region of cells as shown in Figure 11 2 The currently selected cell represents the cell in the upper left corner of the grid of cells Click here H Drag to here PEPE eet Figure 11 2 Selecting the Cells Defining the Plume 11 10 GMS Tutorials 11 11 2 Assigning the Concentration Now that the plume cells are selected The next step is to assign the concentrations to the cells 1 2 Select the Point Sources Sinks command from MT3D menu Select the NAPL option at the bottom of the dialog Enter a value of 2000 for the Initial concentration Enter a value of 3 0 for the Dissolution rate Select the OK button to exit the Point Sources Sinks dialog Click anywhere outside the grid to unselect the cells 11 11 3 Entering the NAPL Data Finally we will enter the remaining NAPL plume data using the NAPL Dissolution Package dialog 1 Select the NAPL Dissolution Package command from the MT3D menu Change the Number of tracers in NAPL value to 2 Change the Number of hydrocarbons in NAPL value to 2 At the bottom of the dialog enter 150 for the Inert fraction molecular weight Select the first item in the list on the left Enter 0 1 for the Initial mass fraction Enter 4400 0 for the Solubility Enter 110 0 for the Molecular weight Select each of the other three specie
84. a set of TINs that represent the interfaces between the soil layers depicted in the borehole data However before constructing the TINs we must first define an extrapolation polygon The extrapolation polygon defines the boundary or the limits of the stratigraphy model In many cases the polygon corresponds to a property boundary Setting Up the View The extrapolation polygon will just enclose the boreholes The polygon will be entered in plan view 4 Select the Plan View macro tex To allow plenty of screen space to enter the polygon we will increase the viewing area zoom out 1 Select the Zoom tool 2 While holding down the Shift key click somewhere in the center of the boreholes Turning on the Drawing Grid We will be entering the extrapolation polygon interactively using the mouse To help guide the placement of the polygon we will temporarily turn on a drawing grid 1 Select the Drawing Grid Options command from the Display menu 2 Set the Spacing to 50 0 3 Turn on the Snap to grid option 4 Turn on the Display grid lines option 5 Set the Grid line spacing increment to 1 6 Select the OK button You should see a grid appear on the screen Notice that as you move the cursor across the Graphics Window the coordinates that appear in the Edit Window at the bottom of the screen move in increments of 50 Stratigraphy Modeling With Solids 3 5 3 7 3 Defining the Boundary Arc We are now ready
85. aasaeceesesesenseaeeecees 12 1 12 3 USING THE TRUE LAYER MODE miran huro i e e e a a a E E r ei a 12 2 12 4 INTERPOLATING TO MODFLOW LAYERG c ccsssscesscecssecesceeceaecesneecsaceeeneecsaeeeeaeecsaeeeeaeecsaeeeeaeesas 12 2 12 52 SAMPLE PROBLEMS i 12 3 12 62 BUILDING THE GRID seuss 12 3 12 7 CASE T COMPLETE LAYERS anicent 12 3 12 7 1 Importing the Scatter Point 12 4 12 7 2 Interpolating the Elevation 12 5 12 7 3 Viewing the Results eee Giese eset A eee a see A eis esa oS 12 5 12 8 CASE 2 EMBEDDED SEAM re iscsccesstessceedecacevasocestesusceeunsv ove 12 6 12 8 1 Importing the Satter Points ss ssicssita cies sieves 12 6 12 8 2 Inter polating the Values E ETE a athe et 12 7 12 8 3 Correcting the Layer KE Ea E aKa Ea EEE EEEE ETE EE S 12 7 12 9 OUTCROPPING ieee a EE E EE E O E E EEE N ET 12 8 12 9 1 Importing the Points 12 8 12 9 2 Interpolating the Vales bea sees ede RS 12 9 xii GMS Tutorials 12 9 3 Correcting the Layer Meebo
86. abyaeatets 14 10 14 10 EDITING THE HYDRAULIC CONDUCTIVITY cccssscccccecsesessscecececeesenseaececececseseaeeeeececeessaeeeeseseeensas 14 10 14 11 CONVERTING THE MODEL 14 11 14 12 COMPUTING A SOLUTION ccccccccccecsssssececececsessaececececsensaaececececeeseseaecececeesesaaecececeesessaaeeeseeeeeeneas 14 12 14121 SAVING ys sd ees oe een sag Sy Ae dee ca Hebe veg eee REUNITE eae 14 12 14 12 2 SRunnitig ENS EES 14 12 Table of Contents xiii 14 13 READINGIN THE SOLUTION sarina 14 12 14 14 ERROR VS SIMULATION PLOT 0 14 13 14 15 CONTINUING THE TRIAL AND ERROR CALIBRATION 14 13 14 15 1 Changing Values vs Changing 7 14 13 14 132 Viewing the Sis cee Moe wus Nas av fas eae vay eA 14 14 TA S16 CONCLUSION cob deasetantegsgeshedreubeb vege 14 14 15 FEMWATER FLOW MODEL csscccssssssscsscsscsscssssssscsncsccsssssesssssnssssssessessessessessnessssnessessessoseeees 15 1 15 1 DESCRIPTION OF PROBLEM wi sssdvissisnescevessvnvesesnessevysnshsssvenesveseveuestpeapsugecesinds 15 1 15 22 GETTING STARTED costvebsen cbievaceatontentevevepron
87. accurate interpolation The next scheme we will try is DW interpolation with planar nodal functions 1 Select the Interp Options command from the Interpolation menu 2 Select the Options button to the right of the Inverse distance weighted option 3 In the Nodal function section at the top of the dialog select the Gradient plane option 4 Select the OK button to exit the 2D IDW Interpolation Options dialog 5 Select the Close button to exit the 2D Interpolation Options dialog To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter idw_planar for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og IDW Interpolation With Quadratic Nodal Functions The nodal functions used in ZDW interpolation can also be quadratic functions which are constrained to pass through the scatter point and approximate the neighboring scatter points in a least squares fashion The averaging or blending of the quadratic functions during the interpolation stage often results in a very smooth surface 1 Select the Interp Options command from the Interpolation menu 2 Select the Options button to the right of the Inverse distance weighted option 3 In the Nodal function section at the top of the dialog select the Quadratic option 4 Select the OK button to exit the 2D IDW Interpolation Options dialog 5 Two Dimensional Geostatistics 4 9 Select the Close b
88. alize the MT3DMS simulation Select the New Simulation command from the MT3D menu The Basic Transport Package The MT3DMS Basic Transport package is similar to a combination of the MODFLOW Basic and BCF packages It is always required and it defines basic information such as stress periods active inactive regions and starting concentration values Select the Basic Transport Package command from the MT3D menu Headings To enter the headings 1 For the first line of the heading enter GMS MT3DMS Tutorial MT3DMS Simulation 2 For the second line of the heading enter your name and the current date Species Since MT3DMS is a multi species model we need to define the number of species and name each species We will use one species named tracer 1 Select the Define Species button 2 Select the New button 9 10 GMS Tutorials 3 Change the name of the species to tracer 4 Select the OK button to return to the Basic Transport Package dialog Packages Next we will select which packages we wish to use 1 2 Select the Packages button Select the Advection Package option Select the Dispersion Package option Select the Source Sink Mixing Package option Select the OK button to exit the Packages dialog Stress Periods The next step is to set up the stress periods The flow simulation was steady state but the transport simulation will be transient We will run the simulation for a one year time per
89. all we will define the units The length and time units will already be set by the MODFLOW model We will specify the mass and concentration units 1 Select the Units button 2 Check to ensure that the length units are feet ft and the time units are days d 3 Change the mass units to milligrams mg 4 Change the concentration units to milligrams per liter mg l 5 Select the OK button to exit the Units dialog The units we have entered are for convenience only and do not affect the calculations GMS displays these units next to the input fields to remind us of the proper units for each item It is still up to the user to enter consistent units 11 6 2 Setting up the Stress Periods The next step is to set up the stress periods Since none of the sources change over the simulation we can use a single stress period with a single time step of 2000 days For the transport step size we will use the default value of zero This forces SEAM3D to compute the appropriate transport step size automatically 1 Select the Stress Periods button 2 Change the length of the stress period to 2000 3 Select the OK button to exit the Stress Periods dialog 11 6 3 Package Selection Next we will select the packages we will be using in the simulation 1 Select the Packages button in the Basic Transport Package dialog 2 Select the following packages Advection Package Dispersion Package Source Sink Mixing Package Chemical Reaction Package Biode
90. als may be completed in either normal or demo mode many of them can only be completed in normal mode The required mode is discussed at the beginning of each tutorial If the tutorial must be completed in normal mode the modules and interfaces needed for the tutorial are listed If some of the required items have not been licensed you will need to obtain an updated password or hardware lock before you complete the tutorial 2 Surface Modeling With TINs The TIN module in GMS is used for general purpose surface modeling TINs are formed by connecting a set of xyz points scattered or gridded with edges to form a network of triangles The surface is assumed to vary linearly across each triangle TINs can be used to represent the surface of a geologic unit or the surface defined by a mathematical function TINs can be displayed in oblique view with hidden surfaces removed Elevations or other values associated with TINs can be displayed with color fringes or contours are used in the construction of solid models and 3D finite element meshes This tutorial should be completed before beginning the Stratigraphy Modeling with Solids tutorial The emphasis in this tutorial is on the basic tools for editing TINs A description of how TINs are used in the construction of solids is provided in the following tutorial 2 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish
91. alue 5 Select the OK button 6 Repeat steps 2 5 to assign a value of 36 25 to the bottom row This concludes the input for the Basic package The BCF Package The next step in setting up the model is to enter the data for the block centered flow BCF package 1 Select the BCF Package command from the MODFLOW menu 2 Inthe Layer Type section choose the Confined option The buttons in the lower right portion of the dialog are for entering layer data First we will enter the top and bottom elevations We will use a constant elevation throughout the grid The bottom elevation is zero and top elevation is ten meters This happens to be the default values assigned to a new grid Thus in this case we don t need to make any changes to the elevations 9 4 5 MT3DMS Grid Approach 9 7 The next value to assign is the horizontal hydraulic conductivity k For our problem the grid will have one k value except for one region which will have a lower value To enter the k values we will first assign a global k value and then select the cells in the low k region and assign the values directly To assign the global k value 1 Select the Horizontal Hyd Conductivity button 2 Select the Constant to Grid button 3 Enter a value of 12 7 note 1 474e 3 m s X 3600 s hr X 24 hr d 12 7 m d 4 Select the OK and Close buttons repeatedly to exit all dialogs Now we will select the cells in the low zone to assign a lower value of
92. ample Unconfined Flow Problem for the Title In the Model Type section select the Unconfined option Select the Saturated with deforming mesh option Select the Units button Select ft for the Length units Select yr for the Time units Select slug for the Mass units Select the OK button to exit both dialogs 17 8 Assigning Material Properties The next step is to define material properties Each element in the mesh is assigned a material id The material ids were automatically assigned to the elements using the polygons when the mesh was constructed At this point all that is left is to enter the hydraulic conductivity 1 2 Select the Material Properties command from the SEEP2D menu Highlight the material entitled Shell Enter a value of 150 for k and 60 k Highlight the material entitled Core Enter a value of 15 for k and 6 SEEP2D Unconfined 17 9 6 Select the OK button 17 9 Assigning Boundary Conditions 17 9 1 The final step in defining the model is to assign boundary conditions to the mesh For the problem we are modeling there are three types of boundary conditions 1 no flow flow is parallel to the boundary 2 specified head and 3 exit face With the finite element method not assigning a boundary condition is equivalent to assigning a no flow boundary condition Therefore all of the boundaries have a no flow boundary condition by default and all that is necessary is to assign t
93. an be interpolated to a TIN mesh or grid To begin the tutorial we will import a scatter point set The scatter point set has been entered into a previously prepared text file using the Tabular Scatter Point File format described in the GMS File Formats document This format is designed for importing scatter point sets only GMS saves scatter point sets using a different format The format uses a simple tabular approach that can be easily prepared using a spreadsheet or text editor The file we will import was generated as an Excel spreadsheet and exported from Excel as tab delimited text To read the scatter point file 1 Switch to the 2D Scatter Point module 2 Select the Import command from the File menu 3 At the bottom of the Open dialog change the filter to sp2 4 Locate and open the directory entitled tutorial geos2d 5 Select the file entitled plumedat sp2 Two Dimensional Geostatistics 4 3 6 Click on the Open button A set of points should appear on the screen These points represent locations where the concentration of a contaminant has been estimated using a soil gas survey Our goal is to generate a map of the contaminant plume 4 4 Changing the Display Options You can change the appearance of the scatter points using the Display Options dialog 1 Select the Display Options macro 2 Turn Data colors option 3 Select the button to the left of the Scatter point symbols toggle 4 Choose o
94. and the starting head With the true layer approach used in GMS top and bottom elevations are defined for each layer regardless of the layer type For a two layer model we need to define a layer elevation array for the top of layer one the ground surface the bottom of layer one and the bottom of layer two It is assumed that the top of layer two is equal to the bottom of layer one The simplest way to define layer elevations is to import a set of scatter points defining the elevations and interpolate the elevations directly to the layer arrays In some cases this is done using one set of scatter points In this case we will use two scatter point sets one for the ground surface and one for the elevations of the bottom of layer one and the bottom of layer two It is often convenient to use two scatter point sets in this fashion due to the source of the points Ground surface points are often digitized from a map while layer elevations typically come from borehole data For most steady state MODFLOW models a constant value of starting head will lead to a good solution In some cases the model stability and speed of 7 20 GMS Tutorials 7 14 1 7 14 2 convergence can be improved by selecting a set of starting heads that are closer to the final solution We will use the latter method Our starting heads will be defined by a surface that is a constant depth below the ground surface Importing the Ground Surface Scatter Points The
95. arallel to the edges PR and RQ 1 Select the Select Elements tool ae 2 Click anywhere inside the element PQR 3 Hit the Delete key or select the Delete command from the Edit menu 4 Click on the OK button to confirm the deletion ak 5 Select the Frame Image macro A Refining the Mesh At this point we have a complete mesh defining the region that we intend to model We could get a solution with this mesh but the solution would not be very accurate because we don t have very many elements In general the denser the mesh the greater the accuracy in the solution We can quickly increase the density of our mesh using the Refine Elements command 1 Select the Refine Elements command from the Modify Mesh menu 2 Click on the OK button to refine the entire mesh 3 Repeat this process to refine the mesh one more time The construction of the nodes and elements is now complete SEEP2D Confined 16 9 16 5 Renumbering the Mesh The next step in the model definition process is to renumber the nodes and elements The sequence that the nodes are numbered has a dramatic impact on the amount of time required by SEEP2D to find a solution The nodes and elements have been numbered in the order that they were created This numbering is not optimal The relative quality of the node numbering is indicated by the nodal half band width The time required for a solution is quadratically proportional to the nodal half band width To view
96. ary for the simulation can be defined at the conceptual model level Once this model is complete the grid is generated and the conceptual model is converted to the grid model and all of the cell by cell assignments are performed automatically The steps involved in performing a MODFLOW simulation using the conceptual model approach are described in this tutorial It is not necessary to complete the MODFLOW Grid Approach tutorial before completing this tutorial 7 1 Description of Problem The problem we will be solving for this tutorial is illustrated in Figure 7 1a The site is located in East Texas We will assume that we are evaluating the suitability of a proposed landfill site with respect to potential groundwater contamination The results of this simulation will be used as the flow field for a particle tracking and a transport simulation in the MODPATH tutorial and the MT3DMS tutorial 7 2 GMS Tutorials North Limestone Outcropping a Seer rrr Proposed SEAT Landfill Well 1 Site Well 2 Creek beds River Figure 7 1 Site to be Modeled in This Tutorial a Plan View of Site b Typical North South Cross Section Through Site We will be modeling the groundwater flow in the valley sediments bounded by the hills to the north and the two converging rivers to the south A typical north south cross section through the site is shown in Figure 7 1b The site is unde
97. at the lower left hand corner of the model near the upper left end of the stream forming the bottom boundary of the model Enter a value of 200 for the elevation and click OK Repeat this process to create a point at each of the locations shown in Figure 15 2 Be sure to enter the proper elevation Figure 15 2 Locations and Elevations for New Points Once the TIN vertices are created we are ready to convert the vertices to a scatter point set 1 Select the TIN gt Scatter Points command in the Build TIN menu 15 18 GMS Tutorials 2 Enter Starting Heads for the scatter point set name and hit OK 3 Select Yes to delete the TIN 15 9 2 Creating the Data Set Finally to define the initial condition we must create a pressure head data set The data set will be saved to a data set file The path to this file will be passed to FEMWATER when the simulation is launched Switch to the 3D Mesh module ttt Select the Initial Conditions command in the FEMWATER menu In the Pressure Head section in the upper left corner of the dialog select the Read from data set file option Select the Generate IC button Select Starting_Heads for the Active 2D scatter point set Enter 200 for the Mininum pressure head Select the OK button When prompted for the file name enter starthd phd and select the Save button Select the OK button to exit the Initial Condition dialog 15 10 Defining the Material Properties The
98. atter Point module Select the bot of layer 2 data set in the Data Set combo box at the top of the screen Select the to Active TIN command in the Interpolation menu 15 12 GMS Tutorials 6 Select the OK button At this point you should see the correct elevations on all three TINs To simplify the display 1 Switch to the TIN module 2 Select the Display Options command in the Display menu 3 Turn off the Vertices option 4 Select the OK button To see a shaded image of the TINs ak 1 Select the Frame Image macro A F 2 Select the Shade macro Og 15 5 6 Building the 3D Mesh We are now ready to build the 3D mesh The 3D mesh is constructed by selecting a pair of TINS and then filling between the TIN with extruded elements 1 Select the Select TINs tool ae 2 Select the top and middle TINs by clicking on the icons for the TINs while holding down the Shift key 3 Select the Fill Between TINs gt 3D Mesh command in the Build TIN menu 4 Enter 2 for the Number of interpolated mesh layers 5 Select the Specify material option 6 Select the material called Upper Aquifer 7 Select the OK button Next we will build the elements for the lower aquifer 1 Select the bottom two TINs 2 Select the Fill Between TINs gt 3D Mesh command in the Build TIN menu FEMWATER Flow Model 15 13 3 Enter 3 for the Number of interpolated mesh layers 4 Select the Specify material option 5 Select
99. bservation well To create the point 1 Select the Create Point tool E 2 Click once anywhere on the model 14 6 GMS Tutorials 14 6 3 4 5 Double click on the value in the edit field at the top of the GMS screen Enter a value of 14661 and select the Tab key Enter a value of 32694 in the Y edit field and select the Tab key To assign the attributes to the point 1 2 Select the Attributes command in the Feature Objects menu Enter Point 1 for the name of the point Turn on the Observed option Note If the Observed option is not on the point can be used to monitor computed values but not to compare computed vs observed values Enter 999 0 for the Observed value Enter 1 5 for the Interval Enter 95 for the Confidence Select the OK button Calibration Target Note that a calibration target is drawn next to the point The components of a calibration target are illustrated in Figure 14 3 The center of the target corresponds to the observed value The top of the target corresponds to the observed value plus the interval and the bottom corresponds to the observed value minus the interval The colored bar represents the error If the bar lies entirely within the target the color bar is drawn in green If the bar is outside the target but the error is less than 200 the bar is drawn in yellow If the error is greater than 200 the bar is drawn in red 14 6 4 Model Calibration 14
100. button to exit the Dispersion Package dialog 9 5 5 The Source Sink Mixing Package Finally we must define the data for the Source Sink Mixing package For our problem we only have one source sink the injection well To define the source at the injection well we need to select the well and assign a concentration 1 Select the cell containing the injection well the upper well by clicking anywhere in the interior of the cell Select the Point Sources Sinks command in the MT3D menu Turn on the Well option Enter a value of 57 87 for the concentration Select the OK button Click outside the grid to unselect the cell 9 5 6 Saving the Simulation We are now ready to save the simulation and run MT3DMS 1 2 3 Select the Save As command from the MT3D menu Locate and open the directory entitled tutoriaNmt3dgrid Enter trans mts for the file name MT3DMS Grid Approach 9 13 4 Select the Save button to save the files 9 5 7 Running MT3DMS To run MT3DMS 1 Select the Run MT3DMS command from the MT3D menu 2 Select OK at the prompt 3 When the simulation is finished close the window and return to GMS 9 5 8 Reading in the Transport Solution To read in the transport solution 1 Select the Read Solution command from the MT3D menu 2 Select the OK button 9 5 9 Changing the Contouring Options When displaying plume data the color fill option often provides excellent results 1 Select the Con
101. cessessosesoescoesocesecsseceseseese 6 1 6 1 DESCR PTON OF a E N ae R A E eS 6 1 62 GETTING STARTED a eE EAE IT 6 2 6 3 REQUIRED MODULES INTERFACES ccsccccccecsesessssececececsenseaececececsensaecesececseneaseaeceesceesessaeseesesenensaaseeeees 6 2 CREATING THE GRID Outed 6 3 6 5 INITIALIZING THE MODFLOW SIMULATION cccccccccsesssstcecececsessaececccecsesesececeeeceesensaaeeeeeceesensaeeeeees 6 3 6 6 THE BASIC PACKAGE 22 2 6 3 oTo Dida es ast tia ade cea Laat 6 4 0 06 22 6 4 0 03 SONS ee soci Se oe oe 6 4 0 6 4 The LBOUND Array ireen a a EEE AART ea Aea EAEE AEAT EE 6 5 6 6 3 Starting Headspin a a a E o ako S p EAE EE A EE S Ea EEES 6 5 6 06 60 Exitingethe Dial o ren E A E A N E 6 6 6 7 ASSIGNING IBOUND VALUES DIRECTLY TO 6 6 6 7 1 Viewing th nn e EE E E EE EEES 6 6 6 7 2 S lecting the Cells ereo TENE S 6 6 6 7 3 Changing the IBOUOND gy Eai Hees 6 6 6 7 4 Checking he Vales sisi geet as lode 6 7 6 8
102. computed Const Head 0 ft in column 1 of eee 0 003 ft d layers 1 amp 2 Drain Unconfined Confined Confined Layer 1 K 50 ft d top elev 200 ft bot elev 150 ft Layer 2 K 3 ft d top elev 150 ft bot elev 400 ft Layer 3 K 7 ft d top elev 400 ft bot elev 700 ft Figure 6 1 Sample Problem to be Solved 6 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 6 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module e MODFLOW interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The MODFLOW Grid Approach 6 3 tutorial cannot be completed in demo mode because the ability to save files is required 6 4 Creating the Grid The first step in solving the problem is to create the 3D finite difference grid 1 Switch to the 3D Grid module 2 Select the Create Grid command from the Grid menu 3 In th
103. contamination from the landfill In the first simulation we will be performing reverse particle tracking from the well on the east side of the model to see if the zone of influence of the well overlaps the landfill In the second simulation we will be performing a forward tracking simulation using an array of particles starting at the landfill to analyze the region of potential contamination for the landfill 8 2 GMS Tutorials 8 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 8 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module H e The Map module e The MODPATH interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing 8 4 Importing the Project The first step is to import the East Texas project This will read in the MODFLOW model and solution and all other files associated with the model To import the project 1 Select the Open command from the File menu 2 In the Open d
104. contrast between the contours and the background image we will change the contour color to blue 1 Select the Contour Options command in the Data menu 2 Click on the Contour color window 3 Select the Color button 4 Select a dark blue color 5 Select the OK button repeatedly to exit all dialogs To view the contours for the second layer 1 Select the down arrow in the mini grid display 2 After viewing the contours return to the top layer by selecting the up arrow 7 19 Viewing the Water Table in Side View Another interesting way to view a solution is in side view 1 Select a cell somewhere near the well on the right side of the model 7 26 GMS Tutorials 2 Select the View J Axis macro Notice that the computed head values are used to plot a water table profile Use the left and right arrow buttons in the mini grid display to move back and forth through the grid You should see a cone of depression at the well When finished Select the View Axis macro a 7 20 Viewing the Flow Budget The MODFLOW solution consists of both a head file and a cell by cell flow CCF file GMS can use the CCF file to display flow budget values For example we may want to know if any water exited from the drains This can be accomplished simply by clicking on a drain arc H 1 Switch to the Map module 2 Choose the Select Arcs tool 3 Click on the rightmost drain arc Notice that the total flux throug
105. cription of Problem The site to be modeled in this tutorial is shown in Figure 15 1 The site is a small coastal aquifer with three production wells each pumping at a rate of 100 000 ft 3 day The no flow boundary on the upper left corresponds to a parallel flow boundary and the no flow boundary on the left corresponds to a thinning of the aquifer due to a high bedrock elevation A stream provides a specified head boundary on the lower left and the remaining boundary is a coastal boundary simulated with a specified head condition The stratigraphy of the site consists of an upper and lower aquifer The upper aquifer has a hydraulic conductivity of 10 ft day and the lower aquifer has a hydraulic conductivity of 30 ft day The wells extend to the lower aquifer The recharge to the aquifer is about one foot per year The objective of this tutorial is to create a steady state flow model of the site 15 2 GMS Tutorials 2 257 4 Olele Point SNA J 28 rO Production Wells Figure 15 1 Site to be Modeled with FEMWATER Flow Model 15 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 15 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The Mesh package the 2D Mesh H and 3D Mes
106. ct slug for the Mass units 3 Select ppm for the Concentration units 4 Select the OK button Defining the Species Since MT3DMS is a multi species model we need to define the number of species and name each species We will use one species named leachate 1 Select the Define Species button 2 Change the name of the species to leachate 3 Select the OK button to return to the Basic Transport Package dialog Defining the Stress Periods Next we will define the stress periods Select the Stress Periods button Since the flow solution computed by MODFLOW is steady state we are free to define any sequence of stress periods and time steps we wish Since the leachate from the landfill will be released at a constant rate we only need one stress period We will enter the length of the stress period i e the length of 10 4 GMS Tutorials the simulation and let MT3DMS compute the appropriate transport time step length by leaving the transport step size at zero 1 Enter 3000 0 for the stress period length days 2 Enter 2000 for the Max transport steps 3 Select the OK button to exit the Stress Periods dialog 10 5 4 Selecting Output Control By default MT3DMS outputs a solution at every transport step Since this results in a rather large output file we will change the output so that a solution is written every time step every 300 days 1 2 Select the Output Control button Select the Print
107. ction Through Site with Layers Truncated by Bedrock 12 10 1 Importing the Scatter Points Before importing the scatter point set we will delete the old points 1 Switch to the 2D Scatter Point module 2 Select the Delete All command from the Edit menu 3 Select OK at the prompt To import the points 1 Select the Import command from the File menu 2 Open the file entitled case4 sp2 Defining Layer Data 12 11 12 10 2 Interpolating the Values To interpolate the values 1 Select the to MODFLOW Layers command 2 Select the OK button 12 10 3 Viewing the Results To view the results 1 Switch to the 3D Grid module 2 Select near the middle of the grid 3 Select the View I Axis macro S 4 Select the View J Axis macro Note how the bottom of the third layer the top of the bedrock cuts into the upper layers 12 10 4 Correcting the Layer Values To correct the layer errors 1 Select the Check Simulation command in the MODFLOW menu 2 Select the Run Check command 3 Select the Fix Layer Errors button In this case a customized option called Truncate to bedrock is perfectly suited to our problem This method examines the elevations for each cell and if the bedrock elevation the bottom elevation for the bottom layer is above the top elevation of the cell the cell 15 made inactive If the bedrock elevation is below the top of the cell but below the bottom the bottom elevati
108. ction coefficients select the Use all points option Select the OK button to exit the IDW Interpolation Options dialog Select the Close button to exit the Interpolation Options dialog Three Dimensional Geostatistics 5 9 To interpolate to the grid 1 Select the to 3D Grid command from the Interpolation menu 2 Enter idw_quad for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og 5 14 Other Interpolation Schemes Two other 3D interpolation schemes natural neighbor interpolation and kriging are supported in GMS However these schemes will not be reviewed in this tutorial You are encouraged to experiment with these techniques at your convenience 5 15 Viewing the Plume With a Cross Section While iso surfaces are effective for displaying contaminant plumes it is often useful to use color shaded cross sections to illustrate the variation in the contaminant concentration Next we will cut a horizontal cross section through the center of the plume 1 Switch to the 3D Grid module T 2 Select the Side View macro t 3 Select the Create Cross Section tool E 4 Cuta horizontal cross section through the grid by clicking to the left of the grid moving the cursor to the right of the grid and double clicking Cut the cross section through the middle of the iso surface z 5 Select the Oblique View macro E Before we shade the cross section we will turn off the display of the iso sur
109. d easily This tutorial describes how to use these tools most effectively 12 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 12 2 Required Modules Interfaces This tutorial can be completed in either demo mode or normal model If you are already in demo mode you may continue with the tutorial If you are in normal mode you will need to ensure that the necessary components have been licensed This tutorial utilizes the following components of the GMS interface H e The Map module 12 2 GMS Tutorials e The 2D Scatter Point module e The 3D Grid module You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If each of these items is enabled you can proceed to complete the tutorial in normal mode If not you will need to switch to demo mode before continuing To switch to demo mode 1 Select the Demo Mode command from the File menu 2 Select OK at the prompts 12 3 Using the True Layer Mode 12 4 For a multi layer MODFLOW model the layer data required by each layer depend on the layer type For example an unconfined layer requires an array of bottom elevations and an array of hydraulic conductivity K values A confined layer requires a transmissivity array
110. default 3 Select the OK button 7 22 GMS Tutorials 7 14 6 Adjusting the Display Now that we are finished with the interpolation we can hide the scatter point sets 1 Select the Select Scatter Point Sets tool bee 2 Drag a box around both of the scatter point set symbols the pentagons 3 Select the Hide macro We will also turn off the grid frame H 1 Switch to the Map module 2 Select the Display Options command in the Display menu 3 Turn off the Grid frame option 4 Select the OK button 7 14 7 Viewing the Model Cross Sections To check the interpolation we will view a cross section 1 Switch to the 3D Grid module 8 2 Select a cell somewhere near the center of the model 3 Select the View J Axis macro fae To get a better view of the cross section we will increase the z magnification 1 Select the Z Magnification command from the View menu 2 Enter a value of 5 for the Z magnification factor 3 Select the OK button You may wish to use the arrow buttons in the Tool Palette to view different columns in the grid Note that on the right side of the cross section the bottom layer pinches out and the bottom elevations are greater than the top elevations This must be fixed before running the model MODFLOW Conceptual Model Approach 7 23 7 14 8 Fixing the Elevation Arrays GMS provides a convenient set of tools for fixing layer array problems These tools are located in the Model Chec
111. default values To interpolate the elevation values 1 Switch to the 2D Scatter Point module E 2 Select the to MODFLOW Layers command in the Interpolation menu The dialog you now see is used to define which scatter point data sets are interpolated to which MODFLOW arrays The data sets are listed at the top left and the MODFLOW arrays are listed at the top right of the dialog The mapped relationships are listed at the bottom of the dialog GMS tries to automatically map the relationships based on the data set names In this case all of the relationships were correctly mapped and we can continue Select the OK button Viewing the Results To view the results we will look at a cross section view Before switching to a side view we will first select a cell in the interior of the model If a cell is selected when switching to a side view the view will change to the row or column passing through the selected cell 1 Switch to the 3D Grid module 2 Select near the middle of the grid 12 6 GMS Tutorials 3 Select the View I Axis macro S Notice that the interpolated layer matches the cross section shown in Figure 12 1 You may wish to use the arrow buttons in the Mini Grid Display to view the cross sections along other rows 12 8 Case 2 Embedded Seam 12 8 1 The next case we will examine is illustrated in Figure 12 3 In this case the middle layer is an embedded seam that only exists on the left West
112. dy state flow model has been previously computed and is supplied with the tutorial files 1 Switch to the 3D Grid Module 2 Select the Read Simulation command in the MODFLOW menu 3 In the Open dialog locate and open the file entitled tutorial seam3d flowmod mfs At this point you should see a grid appear To view the flow solution 1 Select the Read Solution command in the MODFLOW menu 2 Select OK at the prompt A set of head contours should appear indicating a uniform flow field from left side to the right side 11 5 Initializing the SEAM3D Simulation Before entering the SEAM3D data we must first initialize the SEAM3D simulation This allocates the memory and data structures used by GMS to set up a SEAM3D simulation To initialize the simulation Select the New Simulation command from the MT3D menu The interface to MT3DMS RT3D and SEAM3D are all contained in the MT3D menu Now that we have initialized the simulation most of the menu commands in the MT3D menu are undimmed 11 6 Basic Transport Package The next step is to enter the data required by the Basic Transport BTN package The BTN package is used to set up the basic components of the simulation including package selection stress periods and initial conditions 1 Select the Basic Transport Package command from the MT3D menu 2 Inthe Model section of the dialog select the SEAM3D option 11 4 GMS Tutorials 11 6 1 Defining the Units First of
113. e Before we construct the feature objects defining the boundary of the mesh we must first initialize a 2D mesh coverage H 1 Switch to the Map module 2 Select the Coverages command in the Feature Objects menu 3 Change the Coverage Type to SEEP2D 4 Change the name of the coverage to SEEP2D Mesh 5 Select the OK button 17 4 3 Creating the Corner Points We are now ready to create some points at key corner locations These points will then be used to guide the construction of a set of arcs defining the mesh boundary 1 Select the Create Point tool from the Tool Palette 2 Using the coordinate information in the lower left hand window to help you position the cursor create a node at each of the following coordinates the coordinates shown in Figure 17 2 If you create a point at the wrong location you can edit the node coordinates using the Select Points Nodes tool ie When this tool is active you can select points and change the coordinates using the edit fields in the bottom window Highlight the values in the edit fields with the cursor type in a new value and 17 4 4 SEEP2D Unconfined 17 5 hit the Enter key You can also select points and delete them using the Delete key on the keyboard or the Delete command in the Edit menu Once you have created the points you can center the display as follows ak Select the Frame Image macro A F We will now turn the drawing grid off since it is no longer n
114. e OK button To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter ct for the name of the new data set 3 Turn on Map Elevations toggle Note This will cause the interpolated concentrations to be automatically mapped to the z coordinates of the nodes as the data set is interpolated 4 Select the OK button 5 Select the Shade macro Og Once again interpolation was only performed within the convex hull of the scatter point set As with linear interpolation the first step in Clough Tocher interpolation is to triangulate the scatter point set to form a temporary TIN However rather than performing a linear interpolation of each triangle a cubic surface patch is fitted over each triangle and the cubic patches are used in the interpolation Two Dimensional Geostatistics 4 7 4 12 Simple IDW Interpolation The next scheme we will try is a simple form of inverse distance weighted IDW interpolation 1 Select the Interp Options command from the Interpolation menu 2 Select the Inverse distance weighted option 3 Select the Options button to the right of the Inverse distance weighted option 4 In the Nodal function section at the top of the dialog select the Constant option 5 In the section entitled Computation of interpolation weights select the Use all points option 6 Select the OK button to exit the 2D IDW Interpolation Options dialog 7 Select the Close bu
115. e Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required SEEP2D Confined 16 3 16 4 Creating the Mesh 16 4 1 The first step in setting up the problem is to create the finite element mesh Two types of elements can be used with SEEP2D three node triangular elements and four node quadrilateral elements Generating the mesh involves subdividing the problem domain into small triangular and rectangular regions A variety of methods are available in GMS for constructing a 2D mesh For problems with simple geometry the approach described in this tutorial can be used For problems with more complex geometry the Map module approach described in the following tutorial is typically the most efficient method Defining a Coordinate System Before we construct the mesh we must first establish a coordinate system We will use a coordinate system with the origin 90 feet upstream of the sheet pile at the top of the bedrock as shown in Figure 16 2 Figure 16 2 Coordinate System We will begin the mesh construction by creating some nodes at key locations in the mesh Before we create any nodes we must first set the window bounds so that we are viewing t
116. e left side 13 2 GMS Tutorials of the model The narrow regions where the river enters and exits the model are modeled as specified head boundaries There are four major productions wells in the region The site will be modeled using two layers a lower confined layer and an upper unconfined layer The local site is situated in the interior of the model The local site corresponds to a chemical plant with a small spill Once the regional model is completed a local scale model is to be developed and then used to analyze a number of injection extraction well placement scenarios The wells are part of a treatment system that is being designed Fixed _ Oe Head Boundary Fixed Head Boundary Local Site Boundary Figure 13 1 Regional Model The basic goal of the regional to local model conversion process is to create a 2D scatter point set containing the heads and layer data arrays from the regional model create the local model and interpolate the heads and layer data to the local model A 2D scatter point set is used since the MODFLOW arrays should be interpolated on a layer by layer basis using 2D interpolation GMS provides a set of tools that greatly simplify this process The basic steps are as follows 1 Generate the regional model and compute a solution 2 Use the MODFLOW Layers gt 2D Scatter Points command to create the scatter point set with the layer and head data from the regional model 3 Create the
117. e next step is mark the specified head boundaries 1 Select the Select Arcs toot Ml 2 While holding the Shift key select the arcs on the left and right sides of the model 3 Select the Attributes command in the Feature Object menu 4 Change the type to Specified Head 5 At the bottom of the dialog change the layer assignment so that it goes from 1 to 2 6 Select the OK button Normally at this point we would select the nodes of the specified head arcs and assign a head value However we are going to override the head values using the computed heads from the regional model 13 7 Creating the Local MODFLOW Model We are now ready to convert the conceptual model to a grid model First we will create a new grid frame that fits the local model 1 Select the Grid Frame command from the Feature Objects menu 2 Select the Delete Frame button to delete the old frame 3 Select the New Frame button to create a new frame fitted to the new model boundary The grid frame should be slightly larger than the area enclosed by the arcs 4 If desired you can use the rotation handle near the lower right corner of the grid frame to rotate the grid to better match the local grid boundary You may need to move the dialog to edit the grid frame 5 Select the OK button to exit the dialog 13 7 1 Creating the Grid Next we will create the grid 1 Select the Map gt 3D Grid command from the Feature Object menu 13 8 GMS T
118. e north and eventually empties into a lake with elevation 1000 ft Three wells in the basin also extract water from the aquifer The perimeter of the basin is bounded by low permeability crystalline rock There are ten observation wells 14 2 GMS Tutorials in the basin There is also a stream flow gauge at the bottom end of the stream Model Boundaries amp Stresses Head 1000 ft x Well 1 x Well 2 ea Stream x Well 3 Figure 14 1 Sample Model Used in Calibration Exercise The assumed recharge and hydraulic conductivity zones for the model are shown in Figure 14 2 model region encompasses fractured and weathered bedrock as well as alluvial material grading from hydraulically tighter materials in the south to more permeable materials in the north Furthermore the materials around the stream tend to be coarser cleaner and thus more permeable The topmost region of the model near the lake has a high level of phreatophytic plant life The first task of this exercise will be to import a single layer unconfined MODFLOW model that has been constructed for the site This model contains an initial estimate of hydraulic conductivities and recharge A solution computed with this initial model will then be imported and the error in the initial solution will be analyzed New values for hydraulic conductivity and or recharge will then be entered a new solution will be generated and a new error e
119. e of 1 0 for h 4 Enter a value of 0 001 for k 5 Select the material entitled Core 6 Enter a value of 4 0 for h 7 Enter a value of 0 001 for k 8 Select the OK button 17 14 Saving the Simulation We are now ready to save the simulation and compute a new solution 1 Select the Save As command from the SEEP2D menu 2 Enter dam2 sps for the file name 3 Select the Save button 17 14 GMS Tutorials 17 15 Running SEEP2D To run SEEP2D 1 Select the Run SEEP2D command from the SEEP2D menu 2 Select the OK button When the solution is finished close the window and return to GMS 17 16 Viewing the Solution Now that the solution has been computed we can read it back into GMS to display the results graphically In this case since the mesh was not deformed the solution consists of a single file a data set file containing the heads velocities etc 1 Select the Read Solution command in the SEEP2D menu 2 Select the OK button You should see a display of the equipotential lines and flow lines To make the lines more visible 1 Select the Display Options command in the Display menu 2 Turn off the Nodes and Elements options Another useful way to view a sat unsat solution is to create a plot of the phreatic surface This can be accomplished by contouring the pressure head and using a single contour corresponding to zero 1 Select the SEEP2D tab 2 Turn off the Flow lines option 3 Select the OK
120. e of the model through the specified head boundary We will enter the correct background concentrations for fresh water entering through this boundary 1 Select the Select j tool 11 8 GMS Tutorials 2 Select the leftmost column of cells 3 Select the Point Sources Sinks command from the MT3D menu 4 Turn on the Constant head option Once again the default value is zero That is the correct value for most of the species We will change the value for 2 SO4 and H2S 1 Select O2 from the text window containing the species names 2 Enter a value of 4 0 in the Constant edit field 3 Repeat this process to enter the following concentrations S04 9 0 mg L H2S 0 01 mg L 4 Select the OK button to exit the Point Sources Sinks dialog 11 10 Chemical Reaction Package Next we will enter the data for the Chemical Reaction package This package is the standard MT3DMS package that is used to simulate sorption and first order decay The biodegradation reactions are simulated the Biodegradation package that is unique to SEAM3D We will use the Chemical Reaction package to simulation retardation due to sorption 1 Select the Chemical Reaction Package command in the MT3D menu 2 Inthe Sorption combo box select the Linear isotherm option 3 Enter a value of 5 0e7 for the Bulk density The default sorption constant is zero This is the correct value for the conservative tracer and for O2 SO4 and H2S We will enter a non z
121. e section entitled X dimension enter 75000 0 for the Length value and 15 for the Number cells value 4 In the section entitled Y dimension enter 75000 0 for the Length value and 15 for the Number cells value 5 In the section entitled Z dimension enter 15000 0 for the Length value and 3 for the Number cells value The thickness of the cells in the z direction does not affect the MODFLOW computations The dimension we have entered was chosen to make the cells appear square when displayed prior to entering the layer elevation data 6 Select the OK button The grid should appear in your window in plan view A simplified representation of the grid should also appear in the Mini Grid Plot in the Tool Palette 6 5 Initializing the MODFLOW Simulation The next step in setting up the model is to initialize the MODFLOW simulation Select the New Simulation command from the MODFLOW menu 6 6 The Basic Package The input to MODFLOW is subdivided into packages Some of the packages are optional and some are required One of the required packages is the Basic package We will begin with this package 6 4 GMS Tutorials 6 6 1 6 6 2 6 6 3 Select the Basic Package command from the MODFLOW menu Titles First we will enter the titles optional 1 For the first line of the heading enter GMS MODFLOW Tutorial Grid Approach 2 For the second line of the heading enter your name and the current date Package
122. e the well on the east right side Delete the default text string text and type Well 2 Select the Fill behind text option Select the OK button To reposition the text 1 2 a Select the Select Drawing Objects tool EA Click on the text and drag it to a new location To change the text 1 2 3 Double click on the text Change the name to Well 54 Select the OK button To add a title to the drawing 1 2 3 Select the Create Text tool A Click in the top center of the Graphics Window just above the model Enter East Texas Groundwater Model for the title 4 Select the Fill behind text option 7 28 GMS Tutorials Select the Font button Change the font size to 18 pt Select the OK button to exit the Font dialog Select the OK button to exit the Text dialog Sometimes it is useful to use both an arrow and a label to highlight a feature 1 10 11 7 22 Conclusion Click in the lower left corner of the window a few centimeters below the bottom boundary of the model Enter Lampasas River for the text Select the Fill behind text option Select the OK button Select the Create Line tool re Draw a line from the Lampasas River text to the lower model boundary by clicking near the text and then double clicking at the end of the line near the lower boundary Select the Select Drawing Objects tool Double click on the line you just created In the Arro
123. e to Error vs Simulation 7 Select the New button again 8 Change the Observation type to Flux 9 Change the Plot type to Error vs Simulation 10 Select the OK button The change in each of the three error norms from one solution to the next is clearly visible in the bottom two plots The plots are updated as each new solution is read in Ideally as you make changes to the model the error should gradually become smaller and smaller If a bad choice is made in changing the model the error may temporarily increase In most cases it is a good idea to keep a log of the changes made and the resulting errors 14 15 Continuing the Trial and Error Calibration 14 15 1 At this point you are free to continue on your own with the trial and error calibration process using the steps outlined above You may wish to change both the recharge and the hydraulic conductivity values Before you edit the recharge values be sure to make the coverage visible when you select it in the Coverages dialog Changing Values vs Changing Zones For this tutorial you should be able to get a good match between the computed and observed values simply by changing the hydraulic conductivity and 14 14 GMS Tutorials recharge values assigned to the polygonal zones In a real application however you may also need to change the size and distribution of the zones in addition to the values assigned to the zones 14 15 2 Viewing the Answer If you wish t
124. e will set the Refine option so that the mesh is refined around the well FEMWATER Flow Model 15 7 1 Turn on the Refine mesh around point option 2 Enter 150 for the Element size this controls the element size at the well Next we will mark the point as a well point For a well we define the pumping rate and the elevation of the screened interval The screened interval is used to determine which nodes in the 3D mesh to assign the pumping rate to The pumping rate is factored among all nodes lying within the screened interval In our case there will only be one node 1 Turn on the Well option 2 Enter 185 for the Top of screen 3 Enter 195 for the Bottom of screen 4 Enter 100000 for the Flux rate 5 Select OK to exit the dialog Repeat this entire process to create two more wells with the following attributes Well 1 2 X 3854 5026 Y 3034 1872 Z 75 45 Element size 150 150 Top of screen 200 240 Bottom of screen 210 250 Flux rate 100000 100000 15 5 Building the 3D Mesh At this point the conceptual model is complete and we are ready to build the 3D finite element mesh The mesh will consist of two zones one for the upper aquifer and one for the lower aquifer The upper zone will consist of two layers of elements and the lower zone will consist of three layers of elements To build the mesh we will first create a 2D projection mesh using the feature
125. ea Ek kE iaaa 15 12 15 6 sseni e a a 15 13 15 7 CONVERTING THE CONCEPTUAL 15 14 15 8 SELECTING THE ANALYSIS OPTIONS prei pe r A A EE R RA A 15 14 15 8 1 Entering the siss ccsseseiscisecsessssassceescvancpssnsaviasisustessaseyacisassaseseave sede cagectestasesoaieassass 15 14 15 8 2 Setting the Iteration 15 15 15 8 3 Selecting Output Controls 15 15 15 8 4 Defining the ensei osk eak ekea 15 15 15 9 DEFINING INITIAL CONDITIONS E EE 15 16 15 9 1 Creating the Scatter Point Set sis ssn so cee ets Sevens GRU le A ee en 15 16 15 9 2 Creating the Dat Seters innet E E A 15 18 15 10 DEFINING THE MATERIAL 15 18 15 11 SAVING AND RUNNING THE MODE D ort EEs EnSE Va s 15 19 15 12 VIEWING THE SOLUTO N KAKAR A 15 20 15 12 15 ViG witha Fin ess oie aerian TEE o EES ENa E AEE aE aE 15 20 15 12 2 Viewing a Water Table 1 15 2
126. eaeeecececeeaaeceeececeensaeeeeeeseeeneas 4 1 4 3 IMPORTING A SCATTER POINT OE e a E 4 2 4 4 CHANGING THE DISPLAY OPTIONS a er e a e a ier aer a aaO aR 4 3 45 CREATING A BOUND G GRD a e EaR a 4 3 4 6 SELECTING AN INTERPOLATION SCHEME cscccccccscsssessscececececsenseaeceeccecsesssaeeecececeesuaueceeececeesssaeeeeeeeeeeneas 4 4 ENAR INTERPOLATION aa aa aa a aeee aa e a eein 4 4 4 8 e a E e aE a EEEE IE IES 4 5 4 9 MAPPING ELEVATIONS errno E E EE E E Aaa 4 5 7a A KO OI E P N BI NEIN E LDA GRID AEE E tees ea a es aA ee RS E aa ee EA 4 5 4 11 CLOUGH TOCHER INTERPOLATION ccccccccccccsessssececececeesesnscesececeesesnaaececececsesssaeceecceceessaaeseeeeeeeenenaaeees 4 6 4 12 SIMPLETE W INTERPOLATION 4 7 4 13 IDW INTERPOLATION WITH GRADIENT PLANEG scccccccccecsesssceceeececsesssaeceecceceesnsaeceeececeeseaeeeeeeeceeneas 4 7 4 14 IDW INTERPOLATION WITH QUADRATIC NODAL FUNCTIONS csssceceesseeeseeceecesssececseaeeeesseeeenenaes 4 8 ASTD PRUNGATION EA E EEE TET EE EOE EET S 4 9 4 16 NATURAL NEIGHBOR INTERPOLATION cc cccccccccssssssececececsesssaececececeesssaececccecsesssaeceeececeensaeeeeeeseeeneas 4 10 ATT speek gene get caves unehewat evens 4 11 4 17 1 Creating the Experimental
127. ececececsesaaeeecececseeaaeaececsceesenssaeeeesesenensaaeeeeecs 5 6 5 10 FRINGE SPECIFIED RANGE 5 6 5 11 USING HE ZS CALE OPTION e E E O SEE E es 5 7 5 12 IDW INTERPOLATION WITH GRADIENT PLANES 5 8 5 13 IDW INTERPOLATION WITH QUADRATIC FUNCTIONS 2 22 5 8 5 14 OTHER INTERPOLATION SCHEMES ccccecsesssceececsessscececceenssececcecsesauececceesessaaecceceeseaeeesesesesssaeeeeeeenes 5 9 5 15 VIEWING THE PLUME WITH A CROSS SECTION ccccssssssscecececeessaececececceseseeeceeseeesensaaeceeseeesenssaeeeeecs 5 9 5 16 USING THE TRUNCATION OPTION 5 10 5 17 SETTING UP A MOVING CROSS SECTION FILM 5 11 5 17 1 Display Options oen se estes nd rare E 5 11 5 17 2 Setting Up the Film LO p reii nsn EEE R E E EE E 5 12 5 17 3 Playing Back the Film LOOP amp 5 12 5 18 SETTING UP A MOVING ISO SURFACE FILM LOODP c ccccccceesessscecececeesesssaeceeceeesesseaeeeecceceensaeeeeees 5 12 5 19 DELETING THE GRID AND SCATTER POINT DATA cccesccccceceesessscecececeesescaeceeccecsessaeeeecceesentsaeaeeees 5 13 320 CONCLUSION eee 5 13 MODFLOW GRID APPROACH essesesessseesseccoesocesccesecescossecsocecceccoesccescceseces
128. ect OK at the prompt since we only have one coverage the choice here does not matter A set of symbols should appear indicating that the boundary conditions have been assigned 15 8 Selecting the Analysis Options Next we will switch to the 3D Mesh module and select the analysis options 15 8 1 Entering the Run Options First we will indicate that we wish to run a steady state flow simulation 1 Switch to the 3D Mesh module tft 2 Select the Run Options command in the FEMWATER menu 3 For the Type of simulation select Flow only 4 Inthe Steady State vs Transient section select Steady state solution 15 8 2 15 8 3 FEMWATER Flow Model 15 15 The problem we are solving has a very large partially saturated region mainly in the upper left corner of the model The larger the unsaturated zone the more difficult it is to get FEMWATER to converge For these types of problems the Nodal Nodal option is a qood choice for quadrature It is not as accurate as the default option Gaussian Gaussian but it is more stable 1 In the Quadrature selection section select the Nodal Nodal option 2 Select the OK button Setting the Iteration Parameters Next we will adjust the iteration parameters 1 Select the Iteration Parameters command from the FEMWATER menu 2 Set the Max iterations for non linear equation to 100 3 Set the Max iterations for linear equation to 1000 4 Set the Steady state convergence criterion to
129. ect the Options button to the right of the Contours option 4 In the Contour method section in the lower left corner of the dialog select the Color fill between contours option 5 Select OK to exit the Contour Options dialog 6 Select Close to exit the 2D Grid Display Options dialog 4 19 Using the Data Calculator Occasionally it is useful to use the Data Calculator to compare two data sets generated by interpolation As an example we will use the Data Calculator to compute the difference between the kriging and natural neighbor data sets Select the Data Calculator command from the Data menu The currently available data sets are listed in the top of the dialog Each data set is assigned a letter Data sets are referenced in the mathematical expression using the letters The krig data set should be labeled i and the nn data set should be labeled h The next step is to enter an expression to compute the absolute value of the difference between the krig and nn data sets 1 Inthe Expression field enter abs h i 2 Inthe Result field enter Difference 3 Select the Compute button Now that we have computed the difference between two data sets it is helpful to view some basic statistics related to the new data set 4 14 GMS Tutorials Select the Data Set Info button The resulting dialog displays basic statistics related to the active data set such as minimum maximum and mean data values 1 Select the OK b
130. ect the Shade macro Og 2 4 GMS Tutorials 2 7 2 8 Editing TINs As TINs are used in the construction of solids and meshes it is usually necessary to edit a TIN once it has been created In many cases TINs are constructed from a sparse set of points and it is necessary to fill in the gaps between the vertices and sculpt the TIN using the editing tools to ensure that the TIN is a reasonable representation of the surface being modeled A variety of tools are provided in GMS for editing TINs Before reviewing these tools we will reset some of the display options 1 Select the Display Options macro 2 Turn on the Vertices and Contours options 3 Select the Options button to the right of the Contours option 4 In the section titled Contour Interval select the Specified Interval option and change the interval to 20 0 5 Select the OK button to exit the Contour Options dialog 6 Select the Close button to exit the TIN Display Options dialog Dragging Vertices One of the simplest ways to edit a TIN is to drag the vertices with the cursor This can be accomplished with the Select Vertices tool 1 Choose the Select Vertices tool from the Tool Palette 2 Select the Plan View macro im 3 Choose one of the vertices in the interior of the TIN and drag it to a new location Notice that as you move the vertex the contours of the TIN are instantaneously updated to give you visual feedback on the changes that
131. ed as a source term using the NAPL Dissolution package For comparison purposes the model will include a conservative no sorption and a non conservative tracer 11 2 GMS Tutorials 1000 ft gt Plume Specified Drain Bound ounaary GW Flow Elev 7 ft H 22ft soot Vv Bottom elevation 0 ft K 50 ft d Simulation time 2000 d Figure 11 1 Problem to be Solved in SEAM3D Tutorial 11 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 11 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module H Map module e The SEAM3D interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required SEAM3D 11 3 11 4 Importing the Flow Model The first step in setting up the SEAM3D simulation is to import the MODFLOW flow model A stea
132. ed by changing the hydraulic conductivity assigned to the polygonal zones in the conceptual model Before editing the hydraulic conductivity values we will first make the hydraulic conductivity zone coverage the active coverage In the Coverages combo box at the top of the window select the Hydraulic Conductivity coverage To edit the hydraulic conductivity values 1 Select the Select Polygons tool Model Calibration 14 11 While holding the Shift key select polygons 1 and 2 shown in Figure 14 4 Select the Attributes command in the Feature Objects menu Enter a value of 2 0 for the Horizontal K Select the OK button Double click on polygon 3 shown in Figure 14 4 Enter a value of 0 5 for the Horizontal K Select the OK button Click outside the model to unselect the polygon Figure 14 4 Polygons to be Selected 14 11 Converting the Model Now that the values have been edited the next step is to convert the conceptual model to the grid based numerical model 1 Select the Map gt MODFLOW command from the Feature Objects menu At the prompt make sure the All applicable coverages option is selected and select OK 14 12 GMS Tutorials 14 12 Computing a Solution The next step is to save the MODFLOW model with the new values and compute a new solution 14 12 1 Saving the Simulation To save the simulation 1 Switch to the 3D Grid module 2 Select the Save As command from the MODFLOW menu 3
133. ed to select the cells on columns 2 10 of row 8 To select the cells Sal Choose the Select Cells tool Select the cell at i 8 j 2 Notice that as you move the cursor across the grid the ijk indices of the cell beneath the cursor are displayed in the Edit Window at the bottom of the screen 6 10 GMS Tutorials 3 Hold down the Shift key to invoke the multi select mode and select the cells on columns 3 10 of the same row as the cell you have already selected Figure 6 2 7 X Figure 6 2 Cells to be Selected 6 10 2 Assigning the Drains To assign drains to the cells 1 Select the Point Sources Sinks command from the MODFLOW menu 2 Inthe Drain section select the Add option This adds a new instance of a drain to each of the selected cells At this point we must enter an elevation and a conductance for the selected drains The drains all have the same conductance but the elevations are not all the same We will leave the elevation at the default value for now and change the elevations later using the Drain Package dialog 1 Enter a value of 80 000 for the conductance 2 Select the OK button 3 Unselect the cells by clicking anywhere outside the grid MODFLOW Grid Approach 6 11 6 10 3 Assigning the Drain Elevations At this point we could select the drain cells one at a time and use the Cell BC dialog to edit the elevati
134. eeded 1 Select the Drawing Grid Options command from the Display menu 2 Turn off the Snap to grid option 3 Click on the OK button The nodes you have created should resemble the nodes shown in Figure 17 3 without the labels Figure 17 3 Points Created with the Create Point Tool Creating the Arcs Now that the corner nodes are created the next step is to create the arcs defining the boundaries of both the shell and the core of the dam This can be accomplished as follows 1 Select the Create Arc 1001 2 Create a series of arcs around the perimeter of the dam by clicking on the following points in order double click on the last point to end the sequence A B C D I J H G A 3 Create the remaining arcs around the core boundary by clicking on the following points in order double click on the last point to end the sequence G E F H 17 6 GMS Tutorials 17 4 5 Redistributing Vertices Arcs are composed of both nodes and vertices The nodes are the two end points of the arc The vertices are intermediate points between the nodes The gaps between vertices are called edges At this point all of our arcs have one edge and zero vertices When we issue the Map gt 2D Mesh command the density of the elements in the interior of the mesh is controlled by the edge spacing along the arcs Thus we will subdivide the arcs to create appropriately sized edges 1 Choose the Select Arcs tool M 2 Select all of the arcs
135. en in doubt the mesh can be renumbered using several different strings of nodes to find the best numbering sequence To turn off the node numbers 1 2 3 Select the Display Options command from the Display menu Turn the Node numbers option off Select the OK button 16 6 Initializing the SEEP2D Solution Now that the mesh is constructed we can begin to enter the SEEP2D data Select the New Simulation command in the SEEP2D menu 16 7 Setting the Analysis Options First we will enter the analysis options These are global options defining the type of problem we are solving 1 2 Select the Analysis Options command from the SEEP2D menu Enter Sample Confined Flow Problem for the Title In the Model Type section select the Confined option Select the Units button Select ft for the Length units Select yr for the Time units Select slug for the Mass units Select the OK button to exit both dialogs SEEP2D Confined 16 11 16 8 Assigning Material Properties The next step in creating the model is to define material properties There is one set of material properties for each zone of the mesh The material properties are kj k2 and an angle The values and k represent the two principal hydraulic conductivities and the angle is the angle from the x axis to the direction of the major principle hydraulic conductivity measured counter clockwise as shown in Figure 16 7 ky Figure 16 7 Definit
136. ents has been enabled on your copy of GMS by selecting the Register command from the File menu If each of these items is enabled you can proceed to complete the tutorial in normal mode If not you will need to switch to demo mode before continuing To switch to demo mode 1 Select the Demo Mode command from the File menu 2 Select OK at the prompts Constructing the Solid Models Constructing a set of solid models of soil stratigraphy in GMS is a three step process In the first step a set of boreholes is input In the next step a set of surfaces TINs is constructed through contacts on the boreholes which are selected by the user These surfaces represent the interfaces between adjacent soil layers In the third step the surfaces are used to construct solid models of the soil layers Reading Borehole Data The first step in the construction of the solid models is to import a set of borehole logs Borehole data can be entered one of two ways The data can be entered into a text file in the GMS borehole file format described in the GMS Reference Manual Alternately the boreholes can be entered one at a time using the Borehole Editor command in the Boreholes menu In the interest of time we will use the first approach and import a set of boreholes from a previously prepared borehole file The borehole data in this file were obtained from an actual site investigation To read in the file Stratigraphy Modeling With Solids 3 3 1
137. er Observation Wells for the name of the coverage 5 Select Observation for the coverage type 6 Select the Options button below the Observation option This dialog is used to define which object the observation points are to be associated with the type of interpolation used and the names of the observed measurement types 1 Make sure the 3D Grid option is selected 2 Select the 2D within layer option For MODFLOW this is typically the best option It restricts the interpolation to cells in the same layer as the observation point 3 Select the New button in the Measurement Type section 4 Enter Head for the measurement type name 5 Select the OK button to exit the Observation Coverage Options dialog 6 Select the OK button to exit the Coverages dialog 14 6 2 Creating an Observation Point We are now ready to create an observation point The first point we will be creating has the following values xm yify Head ft Interval ft Confidence 14661 32694 999 0 1 5 95 The interval represents the estimated error in the observed value The confidence value represents the confidence in the error estimate The interval can be used as a calibration target Calibration is achieved when the error is within estimated error interval 1 5 ft in this case of the observed value In other words if the computed head falls between 997 5 1000 5 the calibration target is reached for this o
138. erative fashion until the solution converges Based on the boundary conditions for our problem it is reasonable to expect that the heads will range from 36 25 m to 250 m We will assign a constant value for the starting head that is an average of these values 1 Select the Basic Package command from the MODFLOW menu 2 Select the Starting Heads button 3 Select the Constant gt Grid button 9 6 GMS Tutorials 9 4 4 4 Make sure the Apply to variable head cells only option is selected and select the OK button 5 Enter a value of 145 0 6 Select the OK button 7 Select the OK button to exit the Starting Heads Array dialog Constant Head Cells The starting head array is also used in conjunction with the IBOUND array to define constant head cells The negative value in the IBOUND array for a cell marks the cell as a constant head cell but the head associated with the cell is entered in the Starting head array Thus we must enter the constant head values for the top and bottom rows in the starting head array First we will enter the head values along the bottom row of the grid The easiest way to assign these values is by selecting the cells directly in the Graphics Window 1 Select the Close button to exit the Basic Package dialog 2 With the Select i tool still active click anywhere in the top row to select it 3 Select the Cell Attributes command in the MODFLOW menu 4 Enter a value of 250 for the Starting Head v
139. eres uquibvesubebscvucelumsidesetovendaetes 11 3 11 6 1 Defining the UniS 11 4 11 6 2 Setting up the Stress EET i SiS 11 4 11 6 3 P ck g Selections Daa a EES Seagate 11 4 11 6 4 Defining the Speci s i on nnen ceive eee 11 5 11 6 5 Controlan ean E E E E AEE AT E a 11 5 11 6 6 Entering the POvOSity vic coil ai aa a ia A Naa ads S PA e RAEE S TEDES 11 6 11 6 7 Starting Concentrations ateen e oa an ea r Enne secs Es 11 6 TET ADVECTION PACKAGE yne beso a a E E a A Ea E EE E AAE 11 7 11 8 DISPERSION PACKAGE oerein E EE AE EE EPE E EEE E E R 11 7 11 9 SOURCE SINK MIXING PACKAGE ririo ree E EEEE EEE EO E ARA E ES 11 7 11 10 CHEMICAL REACTION PACKAGE niione aan O E RTE ERTO ETAN 11 8 11 11 NAPLE DISSOLUTION PACKAGE eiaei e aE e E aE E a a 11 9 IIIA Selecting the monea n 11 9 11 11 2 Assigning the Concentration 11 10 LATS Entering the NAPE D ta rianne bh aes saa eee 11 10 11 12 11 11 11 121 Concentration ii o eiir eriek a E oi 11 11 11 12 2 Electron Acceptor Coefficients sizesis rreyno i keep akor 11 11 111259 Generation Coefficients pyp na E
140. ero value for the non conservative tracer and for the two substrates 1 Select Tracer Non Conservative from the list 2 Enter a value of 5 0e 9 for the Zst sorption constant 3 Repeat steps 1 2 to enter the same value 5 0e 9 for Benzene and Toluene 4 Select OK to exit the Chemical Reaction Package dialog SEAM3D 11 9 11 11 Dissolution Package 11 11 1 We now ready to enter the data for the NAPL Dissolution package For our problem we must simulate the gradual dissolution of contaminants from a plume into the groundwater In MT3DMS such a situation could be simulated using constant concentration cells injection wells or recharge None of these options results in a realistic simulation of dissolution from a plume The SEAM3D NAPL Dissolution package provides a more realistic representation of a contaminant plume With this package we identify the cells containing the plume and enter the initial concentration and dissolution rate for the contaminants We also enter the initial mass fraction and solubility of each species in the plume SEAM3D then simulates the release of the each of the species over duration of the simulation Selecting the Cells The first step is to select the cells where the plume is located 1 Select the Select Cells tool A 2 Select the Find Cell command from the Grid menu 3 Enter 9 6 and 1 for the I J K value respectively and select OK 4 Drag a rectangle to select a 4
141. es and groundwater divides may be located at a great distance from the site of interest In such cases it is often convenient to perform the modeling study in two phases In the first phase a large regional scale model is constructed and the model is extended to well defined boundaries During the second stage a second smaller local scale model is constructed that occupies a small area within the regional model The groundwater elevations computed from the regional model are applied as specified head boundary conditions to the local scale model The layer data including elevations and transmissivities are also interpolated from the regional to the local model A more detailed representation of the local flow conditions including low capacity wells and barriers not included in the regional flow model can be constructed in the local scale model Regional to local model conversion is often referred to as telescopic grid refinement GMS provides a convenient set of tools that can be used for regional to local model conversion The steps involved in a typical regional to local model conversion using MODFLOW are described in this tutorial Description of Problem The site we will be modeling in this tutorial is shown in Figure 13 1 The main features of the regional model are shown Most of the boundaries are no flow boundaries corresponding to groundwater flow divides bedrock outcroppings and natural flow boundaries A river runs through th
142. es of grids are supported in GMS cell centered and mesh centered While cell centered is appropriate for groundwater models MODFLOW the mesh centered approach is more appropriate when the grid will be used solely for interpolation Select the OK button A grid should appear on the screen that just encompasses the scatter point set 5 7 Simple IDW Interpolation The next step is to select an interpolation scheme First we will use the inverse distance weighted interpolation scheme IDW 1 2 Select the Interp Options command from the Interpolation menu Select the Inverse distance weighted option Select the Options button to the right of the Inverse distance weighted option In the Nodal function section at the top of the dialog select the Constant option In the section entitled Computation of interpolation weights select the Use subset of points option Select the Subset button in the Computation of interpolation weights section Select the Use nearest ___ points option and enter 64 for the number of points Three Dimensional Geostatistics 5 5 8 Select the OK button to exit the Subset Definition dialog 9 Select the Close button to exit the IDW Interpolation Options dialog 10 Select the Close button to exit the Interpolation Options dialog To interpolate to the grid 1 Select the to 3D Grid command from the Interpolation menu 2 Enter idw_const for the name of the new data set 3 Select the OK
143. es of the original vertices to the new vertices created while subdividing the TIN 1 Select the TIN gt Scatter Points command in the Build TIN menu 2 Select the OK button to accept the default name of the new scatter point set 3 Select the No button to indicate that you do not want to delete the existing TIN Subdividing the TIN The next step is to increase the resolution of the TIN by uniformly subdividing the TIN 1 Select the Uniformly Subdivide TIN command from the Modify TIN menu 2 Move the scroll bar to select a subdivision factor of 8 3 Select the OK button Interpolating the Elevations Notice that the contours of the TIN have not changed There are more triangles in the TIN but they still define essentially the same surface To smooth the TIN we must use one of the interpolation schemes and interpolate from the original vertices of the TIN to the new vertices created during the subdivision process 1 Switch to the 2D Scatter Point module Eal 2 14 5 5 Surface Modeling With TINs 2 9 Select the to Active TIN command from the Interpolation menu we will use the default interpolation method Enter a name of new_elev for the new data set Turn on the Map elevations option This ensures that the data set created on the TIN will be used to define the elevations of the TIN vertices Select the OK button The contours on the TIN now appear smoother To better view the variation in the sur
144. esececeesenteaeees 14 3 144 READING IN THE MODE L 0 cccccosssssccscccececsensceuccsececeensnaueesececeensenceeseeecesnsnecacseescesssnnuecseescesnsneenees 14 4 14 9 OBSERVATION Sembee Sade AEE ease es CoE eee 14 4 14 6 ENTERING OBSERVATION POINTS ssssscccececsessssececececsesessececececseneeaececececsesseaesececeesessaaeeeeeeeeeesseaeees 14 4 14 6 1 Creating an Observation Coverage 14 4 14 6 2 Creating Observation 14 5 14 6 3 Calibration Target 14 6 14 6 4 E ck aa oe dee ate eee EE eae co anne eee 14 7 14 7 READING IN A SET OF OBSERVATION POINTS c cccccecsessssececececeessssesecececsessaeseceeecsesenseseeeesesenenteaeees 14 7 14 7 1 Deleting the Current COVErA GC aeiaai siai 14 7 14 7 2 REGAINS in the FOS GER Rn See 14 8 14 8 ENTERING THE OBSERVED STREAM 0 14 8 14 9 GENERATING ERROR PLOTS 3c ycccccceccivecsectacascesssuecessdecessoes seescesvoceetnuntiecedesssesseedteaveesvosecdueasvesvvevecedesees 14 9 14 9 1 Computed vs Observed PlOb iss 14 10 14 9 2 ARI TIE A ge abt eet
145. f scatter points A total head data set is generated by interpolating head values from the scatter points to the nodes of the 3D mesh Finally the pressure head data set is created by subtracting the node elevations from the total head values Creating the Scatter Point Set To define the initial condition we will create a small set of points at the expected elevation of the computed water table surface One way to do this would be to create a tabular scatter point file containing the elevations Another faster method is create the points interactively We will use this method Before digitizing the points we will turn off the flux boundary condition display options 1 Select the BC Display Options command in the FEMWATER menu 2 Turn off the Flux option 3 Select the OK button To digitize the points on screen we will create a new TIN and create a set of TIN vertices As we create each point GMS will prompt for the vertex elevation Once the points are created we will convert the vertices to a 2D scatter point set 1 Switch to Plan View te 4 5 FEMWATER Flow Model 15 17 Switch to the TIN module BA Select the New TIN command in the Build TIN menu Enter starting head for the Name Select the OK button Next we will create the points vertices We will create one point at each of the locations shown in Figure 15 2 Select the Create Vertex tool EEI Click once on the screen to create the point
146. f the landfill 3 While the node is selected enter the exact coordinates of the node in the Edit Window Select the Tab key after entering each coordinate value 4 Select the Select Vertices tool ak 5 Starting with the vertex at the lower right corner of the landfill select each of the three remaining vertices on the arc and enter the exact coordinates shown in the table above Building the Polygons Now that the arcs are defined we can build the polygons 1 Select the Build Polygons command in the Feature Objects menu 2 When you are asked if you wish to build the polygons using all arcs select OK Assigning the Recharge Values Now that the recharge zones are defined we can assign the recharge values We will assign one value to the landfill polygon and another value to the remaining polygon 1 Select the Select Polygons tool 2 Double click on the landfill polygon 3 Turn on the Recharge option and enter a constant value of 0 0002 for the recharge rate Note This recharge rate is small relative to the rate assigned to the other polygons The landfill will be capped and lined and thus will 7 16 GMS Tutorials have a small recharge value The recharge essentially represents a small amount of leachate that escapes from the landfill Select the OK button Double click on the outer polygon Turn on the Recharge option and enter a constant value of 0 0228 for the recharge rate Select the OK button
147. face z Select the Oblique View macro ee Deleting the Scatter Point Set The TIN smoothing process is now completed Since we no longer need the scatter point set we will delete it 1 Select the Delete All command from the Edit menu 2 Select the OK button to confirm the deletion 2 15 Reading Another TIN In GMS several TINs can be modeled at once For example we will now read in another TIN without first deleting the existing TIN Switch to the TINs module G Select the Open command from the File menu Select No at the prompt about saving the project In the Open dialog select the tin filter Select the file entitled surface tin Click on the Open button You should now see two TINs displayed at once 2 10 GMS Tutorials 2 16 Changing the Active TIN Whenever multiple TINs are being modeled one of the TINs is designated as the active TIN Only the active TIN can be edited A TIN can be designated as the active TIN using the combo box at the top of the GMS window 1 Choose the Select TINs tool ie 2 Inthe combo box titled TIN select the sparse item Notice that triangular shaped icons appear at the center of each TIN A TIN is selected by selecting the TIN icon The active TIN has a letter A displayed in the center of the icon A TIN can also be designated as the active TIN by double clicking on the TIN icon For example Double click on the TIN icon entitled surface The letter A is now d
148. faces 1 Select the Display Options macro 2 Turn off the Iso surfaces option GMS Tutorials 3 Select the OK button Next we will set up the display options for the cross section 1 Select the Cross Section Options command in the Data menu 2 Turn on the Interior edge removal option 3 Turn on the Fringes option 4 Select the OK button Finally we will reset the Fringe options 1 Select the Fringe Options command in the Data menu 2 Turn off the Color fringe specified range option 3 Select the OK button To shade the image Select the Shade macro Og 5 16 Using the Truncation Option Notice the range of contaminant concentration values shown in the color legend at the upper left corner of the Graphics Window A large percentage of the values are negative This occurs due to the fact that a higher order nodal function was used Both the quadratic and the gradient plane nodal functions infer trends in the data and try to preserve those trends In some regions of the grid the values at the scatter points are decreasing as you move away from the center of the plume This decreasing trend is preserved by the interpolation scheme and the interpolated values approach zero and eventually become negative in some areas However a negative concentration does not make sense This problem can be avoided by turning on the Truncate values option in the Interpolation Options dialog This option can be used to force all negative value
149. final step in setting up the model is to define the material properties Select the Material Properties dialog from the FEMWATER menu We need to enter a hydraulic conductivity and a set of unsaturated zone curves for each aquifer The items on the left side of the dialog are for transport simulations and can be ignored in our case To define the material properties for the upper aquifer Select the Upper aquifer item in the list at the top of the dialog FEMWATER Flow Model 15 19 Enter a value of 10 0 in the upper left edit field in the Conductivity section and select the sotropic button This should fill in all of the diagonal terms with a value of 10 0 Select the Generate Curves button Enter 6 0 for the Max height above water table In the Preset parameter values section select Silt Select the Compute Curves button Select the OK button To define the material properties for the lower aquifer 1 2 Select the Lower aquifer item in the list at the top of the dialog Enter a value of 30 0 in the upper left edit field in the Conductivity section and select the Jsotropic button Select the Generate Curves button Select the Compute Curves button Select the OK button Select the OK button to exit the Material Properties dialog 15 11 Saving and Running the Model We are now ready to save and run the model 1 2 3 NOTE tutorial Select the Save As command in the File menu Enter femmod
150. g Grid Options command from the Display menu 2 Turn off the Snap to grid option 3 Turn off the Display grid lines option 4 Select the OK button 5 Select the Oblique View macro 3 8 Constructing the Ground Surface TIN You are now ready to construct a TIN using the borehole logs We will begin by constructing a TIN representing the ground surface This TIN will pass through the top of each of the boreholes 3 8 1 Selecting the Contacts Before constructing the TIN you must first select the contacts locations on the boreholes that will be used to create the TIN 1 Switch to the Borehole module p 2 Choose the Select Contacts tool 3 While holding the Shift key click on the top of each of the holes 3 8 2 Creating the TIN Now that you have selected the points on the boreholes where the TIN is to pass through you can construct the TIN by triangulating the points 1 Select the Contacts gt TIN command from the Boreholes menu 2 Select the Auto extrapolate only option 3 8 3 Stratigraphy Modeling With Solids 3 7 3 Select the OK button 4 Enter topblue1l for the name of the TIN 5 Select the OK button A blue TIN should appear Note that the TIN passes through the borehole contacts that were selected and it also extends out to the extrapolation polygon This TIN could now be edited if desired using the TIN editing tools described in the previous tutorial to smooth or reshape the TIN
151. g the conceptual model Conceptual models are constructed using feature objects in the Map module Feature 7 6 MODFLOW Conceptual Model Approach 7 5 objects in GMS have been patterned after Geographic Information Systems GIS objects and include points nodes arcs and polygons Figure 7 2 Points are xy locations that are not attached to an arc Points have unique ids and can be assigned attributes Points are typically used to represent wells Arcs are sequences of line segments or edges which are grouped together as a single polyline entity Arcs have unique ids and can be assigned attributes Arcs are grouped together to form polygons or are used independently to represent linear features such as rivers The two end points of an arc are called nodes and the intermediate points are called vertices Nodes have unique ids and can be assigned attributes Vertices are used solely to define the geometry of the arc Polygons are a group of connected arcs that form a closed loop A polygon can consist of a single arc or multiple arcs If two polygons are adjacent the arc s forming the boundary between the polygons is shared not duplicated Feature objects can be grouped into coverages Each coverage represents a particular set of data Our conceptual model will consist of three coverages a coverage defining the model boundary and the location of the sources sinks a coverage defining the recharge zones and a coverage defining the zone
152. g the solids using the TIN editing tools described in the previous tutorial 3 20 Deleting the Solids and TINs The solids and TINs can be deleted using the New command The New command deletes all data in all modules 1 Select the New command in the File menu 2 Select the No button to confirm 3 21 Conclusion This concludes the Stratigraphy Modeling with Solids tutorial If you were originally running in normal mode and switched to demo mode to complete this tutorial you can switch back to normal mode as follows 3 18 GMS Tutorials 1 Select the Normal Mode command from the File menu 2 Select the OK button at the prompt If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 4 2D Geostatistics Two dimensional geostatistics interpolation can be performed in GMS using the 2D Scatter Point module The module is used to interpolate from sets of 2D scatter points to any of the other object types meshes grids TINs Several interpolation schemes are supported including kriging Geostatistics are useful for setting up input data for analysis codes or for site characterization The tools for manipulating scatter point sets and the interpolation schemes supported in GMS are described in this tutorial The interpolation schemes presented in this tutorial will be easier to understand if you have read Chapter 9 of the GMS Reference Manual This tutorial
153. gradation Package 3 SEAM3D 11 5 NAPL Dissolution Package Select the OK button to exit the Packages dialog 11 6 4 Defining the Species 11 6 5 Next we will define the species used in the simulation 1 2 Ds Select the Define Species button Change the number of Nondegradable Tracers to 2 Change the number of Hydrocarbon Substrates to 2 In the Microbial Processes section of the dialog turn on the SO4 reduction option In the Products to track section of the dialog turn on the H2S option Notice that as we make changes in the left side of the dialog the species names are listed on the right side of the dialog Some of these names are fixed but some are user defined We will supply more meaningful names to the tracers and hydrocarbons 1 In the Names list select the Tracer item and change the name to Tracer Conservative 2 Select the Tracer2 item and change the name to Tracer Non Conservative 3 Select the Substrate item and change the name to Benzene 4 Select the Substrate2 item and change the name to Toluene 5 Select the OK button to exit the Define Species dialog Output Control We will now edit the Output Control data to specify how frequently the solution data should be saved for post processing We will save once every 100 days for a total of 20 data sets over the 2000 day simulation 1 2 3 Select the Output Control button Select the Print at specified times
154. ground surface scatter points have been entered in a simple text file which can be imported to GMS The file is in a tabular format with multiple columns and was created with a text editor The columns include the x and y coordinates and the ground surface elevation 1 Switch to the 2D Scatter Point module i 2 Select the Import command in the File menu 3 Inthe Open dialog select the sp2 filter 4 Locate and open the directory titled tutoriaNmodfmap 5 Select the file titled terrain sp2 6 Select the Open button A set of scatter point symbols should appear on the model Calculating a Starting Head Data Set The starting head values will be defined as a surface parallel to the ground surface at a depth of 10 ft below the ground surface We can define such a data set using the Data Calculator Select the Data Calculator command in the Data menu Note that the available data sets are listed in the top of the dialog We can create a new dialog simply by typing an expression and referencing each data set by the letter shown in the list 1 Inthe Expression field type a 10 2 Inthe Result field type starting head 3 Select the Compute button 4 Select the Done button to exit the dialog MODFLOW Conceptual Model Approach 7 21 7 14 3 interpolating the Heads and Elevations Next we will interpolate the ground surface elevations and starting heads to the MODFLOW grid Select the to MODFLOW Layers command i
155. h PP nodules H e The Map module e The Subsurface Characterization package the Borehole TIN ar and Solid to modules e The Geostatistics package the 2D Scatter Point and 3D Scatter Point 8 modules e The FEMWATER interface FEMWATER Flow Model 15 3 You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 15 4 Building the Conceptual Model 15 4 1 FEMWATER models can be constructed using the direct approach or the conceptual model approach With the direct approach a mesh is constructed and the boundary conditions are assigned directly to the mesh by interactively selecting nodes and elements With the conceptual model approach feature objects points arcs and polygons are used to define the model domain and boundary conditions The mesh is then automatically generated and the boundary conditions are automatically assigned We will use the conceptual model approach for this tutorial Importing the Background Image 15 4 2 Before creating the feature objects we will import a scanned image of the site The image
156. h the arc is displayed in the strip at the bottom of the window Next we will view the flux to the river 1 Click on one of the specified head arcs at the bottom and view the flux 2 Hold down the Shift key and select each of the specified head arcs Notice that the total flux is shown for all selected arcs These same steps can be used to display flux through polygons such as recharge polygons Flux for a set of selected cells can be displayed as follows 1 Switch to the 3D Grid module 8 2 Select a group of cells by dragging box around the cells 3 Select the Flow Budget command from the Data menu This dialog shows a comprehensive flow budget for the selected cells 1 Select Done to exit the dialog 2 Click anywhere outside the model to unselect the cells MODFLOW Conceptual Model Approach 7 27 7 21 Adding Annotation GMS includes a wide selection of tools for preparing graphical output to include in a final report of a modeling study These options include printing exporting DXF or TIFF files and copying images to the clipboard Before printing an image or copying the image into another document it is often useful to add some annotation to the image in order to provide a title or highlight important features Annotation can be added with the drawing tools provided in the Map module For example to place a label on a well 1 6 H Switch to the Map module Select the Create Text tool Click just abov
157. h will be altered so that the top of the mesh coincides with the phreatic surface To guide the iteration process we need to mark all of the nodes on the mesh where the phreatic surface may exit as exit face nodes The region of the mesh where the phreatic surface may exit is illustrated in Figure 17 5 Exit Face a Figure 17 5 Exit Face Boundary Condition To define the exit face boundary conditions 1 Select the node just above the tail water level the node just above the top specified head node on the right side of the dam 2 Holding down the Control key select the node at approximately y 60 ft on the right side of the dam 3 Select the Node BC command from the SEEP2D menu 4 Select the Exit Face option 5 Click on the OK button 17 10 Saving the Simulation We are now ready to save the simulation SEEP2D Unconfined 17 11 1 Select the Save As command from the SEEP2D menu 2 Locate and open the directory entitled tutoriaNs2unc 3 Enter dam1 sps for the file name 4 Select the Save buttton 17 11 Running SEEP2D We are now ready to run SEEP2D 1 Select the Run SEEP2D command from the SEEP2D menu 2 Select the OK button At this point SEEP2D is launched in a new window When the solution is finished close the window and return to GMS 17 12 Viewing the Solution To read the solution 1 Select the Read Solution command in the SEEP2D menu 2 Select the OK button 3 Select OK at the pr
158. he 2D Scatter Point module E H e The Map module e The MODFLOW interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 7 4 Importing the Background Image The first step in setting up the simulation is to import a digital image of the site being modeled This image was created by scanning a portion of a USGS quadrangle map on a desktop scanner The image was saved from the scanning software to a TIFF file using the packbits compression option The 7 4 7 5 GMS Tutorials image was imported to GMS registered and a GMS project file was saved To read in the image we will open the project file Once the image is imported to GMS it can be displayed in the background as a guide for on screen digitizing and placement of model features 7 4 1 Reading the Image To import the image 1 Select the Open command from the File menu 2 Locate and open the directory entitled tutorialnodfmap 3 Select the file entitled start gpr 4 Choose the Open button You should see a message indicating that the image is being resampled Eve
159. he Grid The first step in setting up the flow simulation is to create the grid To create the grid 1 Switch to the 3D Grid module 2 Select the Create Grid command from the Grid menu 3 In the section entitled X dimension enter 1600 0 for the Length value and 32 for the Number Cells value 4 In the section entitled Y dimension enter 2000 0 for the Length value and 40 for the Number Cells value 5 Select the OK button 9 4 GMS Tutorials A grid should appear in the Graphics Window 9 4 2 Initializing the MODFLOW Simulation To initialize a new MODFLOW simulation Select the New Simulation command in the MODFLOW menu 9 4 3 The Basic Package The next step in setting up the MODFLOW simulation is to initialize the data in the Basic package Headings First we will enter the headings and other basic information 1 2 Units Select the Basic Package command from the MODFLOW menu For the first line of the heading enter GMS MT3DMS Tutorial MODFLOW Simulation For the second line of the heading enter your name and the current date Next we will define the model units 1 2 Select the Units button Select m for the Length unit Select d for the Time unit Select kg for the Mass unit Select ppm for the Concentration unit Select the OK button Package Selection Next we will select the packages we wish to use 1 2 Select the Packages button Turn on the Well
160. he proper region of the real world coordinate system in our graphics window To set the window bounds 1 Select the Set Wind Bounds command from the View menu 2 Select the X range to be specified option 3 Set X at left to 10 4 Set X at right to 160 5 Set Y at bottom to 10 6 Click on the OK button 16 4 GMS Tutorials 16 4 2 We also need to set up a drawing grid to help us place the nodes in the proper location To set up the drawing grid 1 Select the Drawing Grid Options command from the Display menu 2 Set the Grid spacing to 2 3 Turn on the Snap to grid option 4 Click on the OK button As you move the cursor across the graphics windows you should see the cursor position updated in intervals of two feet in the lower left window Creating the Corner Nodes We are now ready to create some nodes at key corner locations To create the nodes 1 Switch to the 2D Mesh module 8 2 Select the Create Node tool 2 from the Tool Palette When this tool is active a new node will be created at the cursor position each time you click in the Graphics Window 3 Using the coordinate information in the bottom part of the window to help you position the cursor create a node at each of the following coordinates the coordinates shown in Figure 16 2 If you create a node at the wrong location you can edit the node coordinates using the Select Nodes tool k When this tool is active you can select
161. he specified head and exit face boundary conditions Specified Head Boundary Conditions The specified head boundary conditions for our mesh are shown in Figure 17 4 head 60 ft Figure 17 4 The Specified Head Boundary Conditions To enter the specified head boundary conditions for the region on the left 1 Choose the Select Node Strings tool 2 Select the node on the left face of the dam at 60 ft where the water surface touches the dam on the upstream side If you select the wrong node by mistake press the ESC key 3 While holding down the Control key select the leftmost node on the mesh at y 0 4 Select the Node BC command from the SEEP2D menu 5 Select the Head option and enter a value of 60 6 Click on the OK button To enter the specified head boundary conditions for the region on the right 1 Select the rightmost node on the dam at y 0 17 10 GMS Tutorials 2 While holding down the Control key select the node at y 6 ft where the water surface touches the dam on the downstream side 3 Select the Node BC command from the SEEP2D menu 4 Select the Head option and enter a value of 6 5 Click on the OK button 17 9 2 Exit Face Boundary Conditions The remaining type of boundary condition to enter is the exit face definition Since we are using the deforming mesh option SEEP2D will iterate to find the location of the phreatic surface During this iteration the geometry of the mes
162. herefore all of the boundaries have a no flow boundary condition by default and all that is necessary in this case 15 to assign the constant head boundary conditions Constant Head Boundaries The constant head boundary conditions for our mesh are shown in Figure 16 8 Figure 16 8 Constant Head Boundary Conditions The region on the left in Figure 16 8 represents the top of the mesh on the upstream side that is not covered with the clay blanket The region on the right represents the downstream side of the mesh Using a datum of zero the total head in either case is simply the elevation of the water As mentioned above all other boundaries on the mesh have a no flow boundary condition by default To enter the constant head boundary conditions for the region on the left 1 Choose the Select Nodes tool 2 Using the cursor and noting the cursor coordinates in the lower left corner of the screen locate the node with the coordinates 58 32 This node represents the left end of the clay blanket Drag a box which just encloses this node and all of the other nodes on the top boundary to the left of this node 3 Select the Node BC command from the SEEP2D menu 4 Select the Head option and enter a value of 43 5 SEEP2D Confined 16 13 Select the OK button To enter the constant head boundary conditions for the region on the right 1 10 Using the cursor and noting the cursor coordinates in the lower left co
163. ialog locate and open the directory entitled tutorialmodfmap sample 3 Select the file entitled sample gpr 4 Choose the Open button 8 5 Initializing the MODPATH Simulation Now that the MODFLOW model is in memory we can initialize the MODPATH simulation MODPATH 8 3 Switch to the 3D Grid module Select the New Simulation command from MODPATH menu 8 6 Assigning the Porosities In order to calculate the tracking times a porosity must be defined for each of the cells in the grid We will assign one porosity value to layer one and another to layer two Porosities will be assigned to polygons in the conceptual model and then converted to the grid cells using the Map gt MODPATH command H 1 Switch to the Map Module 2 In the Coverages combo box at the top of the GMS window select the Layer I coverage 3 Choose the Select Polygons Tool 4 Double click on the layer polygon 5 Turn on the Aquifer Porosity option and enter a value of 0 30 for the porosity 6 Select the OK button Next we will assign a porosity value to layer 2 1 In the Coverages combo box at the top of the GMS window select the Layer 2 coverage 2 Double click on the layer polygon 3 Turn on the Aquifer Porosity option and enter a value of 0 40 for the porosity 4 Select the OK button 5 Click anywhere outside the model to unselect the highlighted polygon 8 6 1 Assigning the Porosities to the Cells The last step
164. ied Head AP cS 7 8 7 0 Defining the Drain sa anand ce tutes 7 10 7 6 6 Building the polygons ii enee oea eE EEE EE EEEE EEEE EOE anneta 7 12 7 60 77 Creating the a eaa R E E Sak EE ook cactvsaneeceDuage dues AER aki 7 13 77 DELNEATING THE RECHARGE ZONES 7 14 LA Switching COVETAG OSs Wt eee eS 7 14 77 2 Creating the Landfill Boundary E 7 14 72 3 Building the POW SOs gees a ahaa tes 7 15 7 7 4 Assigning th Recharge Values s c isssssesgiessapsssessiesasessestisnsseesdeaseseisssesnciseasostssesedbeasessepeavegeeste 7 15 7 8 DEFINING THE HYDRAULIC CONDUCTIVITY c cccccsssssesssscssesscsseessesecssesscseseseseesssesesesessssessseseseessaeseaeass 7 16 EOD LAV ON dia enh ag ka ba Pea aa bob oR E 7 16 7 8 2 Bottom Laye Fnr n A S eda 7 16 TI LOCATING THE GRIDERAME ir ohe eae re eE E AEEA EEE EEn OE EREE ESE DEE EEEE 7 17 FAQS CREATING THE GRID zarren ee E S a E S E ER e 7 18 7 11 DEFINING THE ACTIVE INACTIVE ZONES 7 18 7 12 INITIALIZING THE MODFLO
165. ilateral elements by triangulating the nodes and then merging the triangles into quadrilaterals 1 Select the Create Linear Triangle Element tool 2 Select the Triangulate command from the Build Mesh menu 3 Select the Merge Triangles command from the Modify Mesh menu 4 Click the OK button to confirm the merging of the entire mesh 5 Click the OK button to confirm the angle The mesh should now appear as shown in Figure 16 5 Figure 16 5 Mesh of Quadrilateral Elements Deleting the Sheet Pile Element The next step is to make sure the sheet pile is properly represented in the mesh The sheet pile is a no flow boundary Thus we need to have a crack in the mesh in the location of the sheet pile We can accomplish this by deleting the narrow element at the location of the sheet pile To select the element we must first zoom in on the sheet pile location 1 Select the Zoom tool 2 Drag a box which just encloses the nodes shown in Figure 16 5 At this point you should have a close up view of the area around nodes P Q and R as shown in Figure 16 6 16 8 GMS Tutorials 16 4 7 Figure 16 6 Region of Mesh where Sheet Pile is Located As shown in Figure 16 6 because we added the point Q just to the right of point P there is a long thin triangle joining nodes P Q and R Since the sheet pile represents an impervious boundary we must delete the element PQR This will cause the flow to occur p
166. ilding the Local Model Next we will build the local model There are numerous approaches to building the local model A common approach is to mark the boundaries of the local model as specified head boundaries using the computed head values from the regional model There are two methods to accomplish this objective 1 A simple rectangular grid is constructed and the entire perimeter of the grid is marked as a specified head boundary 2 A four sided grid is constructed where two opposite boundaries are parallel to head contours from the regional model i e a constant head value along each boundary The other two boundaries are no flow 13 6 Regional To Local Model Conversion 13 5 boundaries and are perpendicular to the head contours from the regional model We will use the second method Building the Local Conceptual Model The simplest way to build the local model is to create a conceptual model in the Map module To do this we will create a new source sink coverage First we will delete the source sink coverage for the regional model H Switch to the Map module Select the Coverages command from the Feature Object menu Check to make sure that the ss coverage is active Select the Delete button Select OK to confirm 13 6 1 Creating a New Coverage Next we will create a new source sink coverage 1 2 3 4 Select the New button Change the name of the coverage to local ss Change the coverage
167. in assigning the porosities is to convert the porosities defined at the polygons to cell by cell values 8 4 GMS Tutorials 1 Select the Map gt MODPATH command in the Feature Objects menu 2 Select OK at the prompt 8 7 Defining the Starting Locations Next we need to specify the starting locations for the particles We will create a set of particle starting locations surrounding the cell containing the well on the east side of the model 8 7 1 Selecting the Cell To assign the starting locations we must first select the cell containing the well To make sure we select the correct cell we will zoom in on the model in the area of the well 1 Switch to the 3D Grid module 2 In the mini grid display in the Tool Palette select the down button to move to the second layer the well is in the bottom layer 3 Select the Zoom tool 4 Click once on the location of the well on the right side of the model This zooms the image by a factor of two around the point clicked 5 Click multiple times if necessary until the cell containing the well is clearly distinguishable from the surrounding cells To select the cell al 1 Select the Select Cells tool HE 2 Click in the cell containing the well 8 7 2 Creating the Starting Locations To generate the starting locations 1 Choose the Generate Particles command from the MODPATH menu 2 Select the Distribute starting points on cell faces option MODPATH 8 5
168. iod To do this we will use a single stress period since the input values are constant and allow MT3DMS to determine the appropriate transport step size 1 Ds Select the Stress Periods button Change the Length field to 365 Make sure the value in the Transport step size is zero A value of zero signifies that MT3DMS will automatically compute the appropriate transport step size Select the OK button to exit the Stress Periods dialog Output Control Next we will specify the output options 1 2 Select the Output Control button Select the Print or save at specified interval option Change the specified interval to 10 This will output a solution at every tenth transport step Select the OK button to exit the Output Control dialog MT3DMS Grid Approach 9 11 ICBUND Array The ICBUND array is similar to the IBOUND array in MODFLOW The ICBUND array is used to designate active transport cells ICBUND gt 0 inactive transport cells CBUND 0 and constant concentration cells ICBUND lt 0 In most problems ICBUND will be similar to IBOUND but it will differ Typically the cells which are constant head cells in the flow solution are not constant concentration cells in the transport solution For our problem all of the cells are active therefore no changes are necessary Starting Concentration Array The starting concentration array defines the initial condition for the contaminant concentration In our p
169. ion of Hydraulic Conductivity Angle With most natural soil deposits the major principal hydraulic conductivity is in the x direction the minor principal hydraulic conductivity is in the y direction and the angle is zero Each element in the mesh is assigned a material id The material id is an index into a list of material properties All of the elements we have created so far have a default material id of 1 This is sufficient since we only have one soil type in our problem To enter the properties for material 1 1 Select the Material Properties command from the SEEP2D menu 2 Enter a value of 100 for both k and 3 Select the OK button Note The units for hydraulic conductivity are L T length time The length units should always be consistent with the units used in defining the mesh geometry Any time units can be used However small time units such as seconds will result in very small velocity values and may make it difficult to display velocity vectors It is recommended that time units of days or years be used 16 12 GMS Tutorials 16 9 Assigning Boundary Conditions 16 9 1 The final step in defining the model is to assign boundary conditions to the mesh For the problem we are modeling there are two types of boundary conditions constant head and no flow flow is parallel to the boundary With the finite element method not assigning a boundary condition is equivalent to assigning a no flow boundary condition T
170. iso surface with the grid cells The edges are displayed to help the user visualize the spatial variation or relief in the iso surface However it is sometimes useful to inhibit the display of the edges in some areas For example in the regions where the plume intersects the grid the iso surface is flat We will turn off the display of the edges in this area since they provide little benefit 1 Select the Jso Surface Options command from the Data menu 2 At the bottom of the dialog select the Interior edge removal option This removes the edges between adjacent planar facets that are coplanar 3 Select the OK button 4 Select the Shade macro Og 5 10 Fringe Specified Range You may have noticed that the shell of the iso surface is all one color but the interior of the iso surface where the iso surface intersects the boundary of the grid varies in color according to the contaminant concentration We can change the display options so that the color variation in this region is more distinct 1 Select the Fringe Options command from the Data menu 2 Select the Color fringe specified range option 3 Enter 3000 for the Minimum fringe value 4 Enter 9000 for the Maximum fringe value 5 Select the OK button 5 11 Three Dimensional Geostatistics 5 7 6 Select the Shade macro Og Using the Z Scale Option The scatter points we are using were obtained along vertical traces In such cases the distances between scatter p
171. isplayed in the icon for the TIN we just read from a file This TIN can now be edited 2 17 Hiding and Showing TINs When multiple TINs are in memory it is sometimes useful to hide some of the TINs temporarily This makes the display less cluttered and makes it easier to edit or visualize an individual TIN For example 1 Select the TIN entitled sparse by clicking once on the TIN icon E 2 Select the Hide macro from the Tool Palette 2 18 Deleting the TINs Since we are now finished with the TINs we will delete them 1 Select the New command from the File menu 2 Select the No button to confirm the deletion 2 19 Conclusion This concludes the Surface Modeling With TINs tutorial Now that you have finished this tutorial and understand the basics of TIN modeling you are Surface Modeling With TINs 2 11 prepared to proceed to the tutorial entitled Stratigraphy Modeling with Solids Chapter 3 If you were originally running in normal mode and switched to demo mode to complete this tutorial you can switch back to normal mode as follows 1 Select the Normal Mode command from the File menu 2 Select the OK button at the prompt If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 3 Stratigraphy Modeling With Solids The Solid module of GMS is used to construct three dimensional models of stratigraphy Once such a model is created cross
172. itled tutorial tins 5 Select the file entitled verts tin 6 Select the Open button A set of points should appear on the screen 2 4 2 5 2 6 Surface Modeling With TINs 2 3 Triangulating To construct a TIN we must triangulate the set of vertices we have imported To triangulate the points Select the Triangulate command from the Build TIN menu The vertices should now be connected with edges forming a network of triangles The triangulation is performed automatically using the Delauney criterion The Delauney criterion ensures that the triangles are as equi angular as possible In other words wherever possible long thin triangles are avoided A more complete description of the triangulation algorithm can be found in Chapter 4 of the GMS Reference Manual Contouring Now that the TIN is constructed we can use it to generate a contour plot of the TIN elevations 1 Select the Display Options macro 2 Turn on Contours and TIN Boundary options and turn off the Triangles and Vertices options 3 Select the OK button The contours are generated by assuming that the TIN defines a surface that varies linearly across the face of each triangle Shading Another way to visualize a TIN is to shade the TIN 1 Select the Display Options macro EN 2 Turn off the Contours and TIN Boundary options and turn on the Triangles option 3 Select the OK button z 4 Select the Oblique View macro E 5 Sel
173. ix Selected Layer button 4 Select OK to exit the Fix Layer Errors dialog 5 Select Done to exit the Model Checker dialog Note that the seam is now properly modeled You may wish to use the arrow buttons in the Mini Grid Display to view the cross sections along other rows 12 9 Case 3 Outcropping 12 9 1 The next case we will examine is shown in Figure 12 4 In this case the top layer is an outcropping that only exists on the left side of the model We will model this case using a three layer model and adjusting the thickness of the top layer so that it goes to a very small value on the right side of the model Figure 12 4 Typical East West Cross Section Through Site with Outcropping Importing the Points In this case the elevations for the scatter points have been adjusted so that the bottom of the first layer extends above the top of the second layer on the right side of the model After interpolating the values we will then adjust the elevations Before importing the scatter point set we will delete the old points 1 Switch to the 2D Scatter Point module 2 Select the Delete All command from the Edit menu 3 Select OK at the prompt To import the points 12 9 2 1 2 Defining Layer Data 12 9 Select the Jmport command from the File menu Open the file entitled case3 sp2 Interpolating the Values 12 9 3 To interpolate the values 1 2 Select the
174. ker 1 Select the Check Simulation command in the MODFLOW menu 2 Select the Run Check button 3 Select the Fix Layer Errors button at the top of the dialog Notice that many errors were found for layer two There are several ways to fix these layers We will use the Truncate to bedrock option This option makes all cells below the bottom layer inactive 1 Select the Truncate to bedrock option 2 Select the Fix Affected Layers button it does not matter which layer is selected all layers that are affected will be fixed 3 Select the OK button to exit the Fix Layer Errors dialog 4 Select the Done button to exit the Model Checker Notice that the layer errors have been fixed Another way to view the layer corrections is in plan view 1 Switch to plan view by selecting the View K Axis macro 2 In the mini grid display select the down arrow to view the second layer Notice that the cells at the upper Northern edge of the model in layer two are inactive Switch back to the top layer by selecting the up arrow 7 15 Checking the Simulation At this point we have completely defined the MODFLOW data and we are ready to run the simulation However before saving the simulation and running MODFLOW we should run the MODFLOW Model Checker one more time and check for other errors Because of the significant amount of data required for a MODFLOW simulation it is often easy to omit some of the required data or to
175. lay menu 2 Select the Options button 3 Select the Use selected data set option 4 In the list of data sets select both tracers and both substrates and turn on the Display toggle for each 5 Select the OK button to exit the Time Series Plot Options dialog 6 Turn on the Curve legend option this will help us distinguish which data set goes with which curve 7 Select the OK button to exit the Observation Plot Options dialog Once again note that you can move the point anywhere in the grid and the plot is updated SEAM3D 11 17 11 18 Other Viewing Options At this point you may wish to experiment with other viewing options For example you may also wish to set up a film loop animation using the Film Loop command in the Data menu 11 19 Conclusion This concludes the SEAM3D tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 12 Defining Layer Data For sites with complex stratigraphy and three dimensional flow a multi layer MODFLOW model can be much more accurate than a one layer two dimensional model When creating multi layer models defining layer data can be challenging This is particularly true for cases involving embedded seams pinchouts and truncations Fortunately GMS contains a suite of tools for interpolating and manipulating layer elevation data With these tools even complex geologic strata can be modeled quickly an
176. lect the Read Solution command from the MT3D menu 2 Select the OK button 3 Inthe TS combo box at the top of the window select the last time step It is often helpful to use the color filled contours option To do this 1 Select the Contour Options command in the Data menu 2 Select the Contour specified range option 3 Enter 1 0 for the minimum value and 120 0 for the maximum 4 Change the Contour Method to Color fill between contours 5 Select the OK button to exit the Contour Options dialog MT3DMS Conceptual Model Approach 10 9 You should now see a display of color shaded contours confined to the area adjacent to the landfill Note that the leachate eventually reaches both the river and the well To view the solution for layer two Select the down arrow in the mini grid display To view the solution in cross section view 1 2 Select the up arrow in the mini grid display Select a cell in the vicinity of the landfill Select the View J Axis macro cit Use the left and right arrow keys to view the solution along different columns E Select the View K Axis macro i when finished 10 16 Viewing a Film Loop Next we will observe how the solution changes over the course of the simulation by generating a film loop animation To set up the film loop 1 2 6 Select the Film Loop command in the Data menu Select the Setup button Turn on the Display clock option Select the Use cons
177. licking on the points if you make a mistake and wish to back up a point or two press the Backspace key If you wish to abort the arc and start over press the ESC key Ste yae TINE JANS PLN STON AN 5 A d Click points along ai e Double click limestone 4 here to end i 4 c Click points along this river Figure 7 3 Creating the Boundary Arc Copying the Boundary Since this arc defines the boundary of the model it is useful to use this same boundary in the other coverages we will be creating Thus we will save a copy of this arc in a set of coverages for later use First we will create a coverage for hydraulic conductivity for each layer 1 Select the Coverages command in the Feature Objects menu 2 Select the Copy command 3 Change the name of the new coverage to Layer 1 4 Select the Options button 7 8 GMS Tutorials 7 6 4 10 11 12 Change the Coverage type to MODF MT3D MODP layer attributes Select the OK button With the Layer 1 coverage still highlighted select the Copy command again Change the name of the new coverage to Layer 2 Select the Options button Change the Coverage type to MODF MT3D MODP layer attributes In the middle of the dialog change the Assign from layer and to layer fields to 2 and 2 this will associate the coverage with layer 2 Select the OK button Next
178. lors option Select the OK button Select the Color Ramp Options command from the Data menu Turn on the Show color legend option Select the OK button Notice that most of the values are zero The nonzero values are all at about the same depth in the holes This pattern is fairly common when dealing with light non aqueous phase liquids LNAPLs which form a pancake shaped plume and float on the water table 5 5 Z Magnification Next we will magnify the z coordinate so that the vertical variation in the data is more apparent 1 2 3 Select Z Magnification command in the View menu Enter a value of 2 0 Select the OK button 5 6 Creating a Bounding Grid To generate a graphical representation of the contaminant plume we must first create a grid that bounds the scatter point set We will then interpolate the data from the scatter points to the grid nodes The grid will then be used to generate iso surfaces To create the grid 5 4 GMS Tutorials 6 Select Bounding Grid from the Scatter Points menu Notice that the x y and z dimensions of the grid are already defined The default values shown in the dialog cause the grid to extend beyond the scatter points by 10 on each side Enter 30 for the number of cells in the x direction Enter 10 for the number of cells in the y direction Enter 10 for the number of cells in the z direction Check to ensure that the default grid type is Mesh Centered Two typ
179. ls on the middle layer First we need to view the middle layer Select the Decrement button in the Mini Grid Plot To select the cells 1 While holding down the Shift key select the following cells rowo lay 4 6 2 26 1 12 2 These cells are shown in Figure 6 4 3 Select the Point Sources Sinks command from the MODFLOW menu MODFLOW Grid Approach 6 13 4 Inthe Well section select the Add button 5 Enter a Flow value of 432000 6 Select the OK button 7 Unselect the cells by clicking anywhere outside the grid Constant Head Cells __ Select these cells 1 Oo Oo oe Oo oe oOo Oo oO Oo Oo Oo oe oO Figure 6 4 Cells to be Selected on Middle Layer 6 11 3 Bottom Layer Well Finally we will define a single well on the bottom layer To view the bottom layer Select the Decrement button in the Mini Grid Plot To select the cell 1 Select the following cell row i tay k 5 11 3 The cell is shown in Figure 6 5 3 Select the Point Sources Sinks command from the MODFLOW menu 6 14 GMS Tutorials 4 Inthe Well section select the Add button 5 Enter a Flow value of 5 0 6 Select the OK button 7 Unselect the cells by clicking anywhere outside the grid Select this cell
180. lygon In this case we will use one polygon since we have a single recharge value 1 Select the Build Polygon command from the Feature Objects menu 2 Select OK at the prompt to indicate we want to use all arcs Assigning the Recharge Next we will assign the recharge value There two ways to assign recharge in FEMWATER using a specified flux boundary or using a variable boundary The variable boundary is more accurate but it is more time consuming and less stable To ensure that the tutorial can be completed in a timely fashion we will use the simpler specified flux approach 1 Select the Select Polygons tool 2 Double click anywhere in the interior of the model domain 3 Turn on the Fluid flux option 4 Enter a value of 0 003 for the flux this value is in ft d and corresponds to about 1 1 ft yr 5 Select the OK button 6 Click anywhere outside the polygon to unselect it 15 4 9 Creating the Wells The final step in defining the conceptual model is to create the wells To create the first well do the following 1 Select the Create Point tool 2 Click on a point anywhere in the upper right corner of the model 3 Using the edit fields at the top of the screen change the xyz coordinates of the point you just created to 5290 4206 45 Hit the Tab or Enter key after entering each value 4 With the point still selected select the Attributes command from the Feature Objects menu First w
181. m the blue TIN down to the red or green TIN whichever is higher Stratigraphy Modeling With Solids 3 15 1 Select the TIN entitled topblue1 2 While holding the Shift key select the TIN entitled topgreen 3 While holding the Shift key select the TIN entitled topred 4 Select the Fill Between TINs gt Solid command from the Build TIN menu 5 Enter bluel for the name of the solid 6 Select the OK button 3 17 Viewing the Solids At this point all of the solids are constructed and the stratigraphy model is complete To view the model in shaded mode Select the Shade macro Og 3 18 Cross Sections Another useful way to visualize a stratigraphy model is to construct cross sections through the model 3 18 1 Creating the Cross Sections To construct a set of cross sections 1 Switch to the Solid module tol 2 Select the Create Cross Section tool 3 Select the Plan View macro tex 4 Cut across section through the solids by clicking on one side of the solids moving the cursor to the other side of the solids and double clicking Cut the solid through the line A A as shown in Figure 3 4 Repeat this process to create cross sections at the lines B B C C D D and 3 16 GMS Tutorials Figure 3 4 Location of Cross Sections 3 18 2 Hiding the Solids Before viewing the cross sections we need to select
182. marked on the background image and are color coded 1 Select the Create Arc 1001 2 Using the boundary lines shown on the backround image create one arc for each of the three marked boundaries on the left side of the model Click on a series of points along each line to trace the arc and double click at the end of the boundary to end the arc Make sure the arcs are connected by starting one arc precisely at ending point of the previous arc 3 Create an arc for the coastline boundary Once again be sure the arc is connected to the other boundary arcs Redistributing the Arc Vertices The two endpoints of each arc are called nodes and the intermediate points are called vertices These arcs will be used to generate a 2D mesh that will be converted into a 3D mesh The spacing of the line segments defined by the vertices will control the size and number of elements Thus we need to redistribute the vertices along each arc to ensure that they are evenly spaced and of the correct length 1 Select the Select Arcs too lll 2 Select all of the arcs by dragging a box that encloses all of the arcs FEMWATER Flow Model 15 5 3 Select the Redistribute Vertices command in the Feature Objects menu 4 Change the Target spacing to 300 5 Select the OK button 15 4 6 Defining the Boundary Conditions Now that the arcs are defined we can assign boundary conditions to the arcs The two no flow boundaries do not need to be
183. menu 2 Locate and open the file entitled tutorial veg2loc regmod gpr 13 4 GMS Tutorials We are now viewing the top layer of the two layer model You may wish to use the arrow buttons in the Tool Palette to view the bottom layer The wells are located in the bottom layer When you are finished return to the top layer This model was constructed using the conceptual model approach The boundary of the local site is indicated with a red rectangle The conceptual model consists of three coverages The coverage we are viewing is for the sources and sinks There is also a coverage defining recharge zones and a coverage defining hydraulic conductivity zones for the top layer The large rectangular boundary is the grid frame The project we imported includes the solution for the regional model You should see contours of computed head 13 4 Converting the Layer Data to a Scatter Point Set The first step in converting the regional model to a local model is to convert the MODFLOW layer data to a 2D scatter point set 1 Switch to the 3D Grid module 2 Select MODFLOW Layers gt 2D Scatter Points command from the Grid menu 3 Change the scatter point set name to Regional Data 4 Select the OK button You should see a set of scatter points appear at the location of the cell centroids This scatter point set has a data set for the computed heads and for the top and bottom elevations of the model layers 13 5 Approaches to Bu
184. meter 7 12 Initializing the MODFLOW Data Now that the grid is constructed and the active inactive zones are delineated the next step is to convert the conceptual model to a grid based numerical model Before doing this however we must first initialize the MODFLOW data 1 Switch to the 3D Grid module MODFLOW Conceptual Model Approach 7 19 2 Select the New Simulation command from the MODFLOW menu 7 13 Converting the Conceptual Model We are now ready to convert the conceptual model from a high level feature object based definition to a grid based MODFLOW numerical model H 1 Switch to the Map module 2 Select the gt MODFLOW command in the Feature Objects menu 3 Make sure the All applicable coverages option is selected and select OK Notice that the cells underlying the drains wells and specified head boundaries were all identified and assigned the appropriate sources sinks The heads and elevations of the cells were determined by linearly interpolating along the specified head and drain arcs The conductances of the drain cells were determined by computing the length of the drain arc overlapped by each cell and multiplying that length by the conductance value assigned to the arc In addition the recharge and hydraulic conductivity values were assigned to the appropriate cells 7 14 interpolating Layer Elevations The final step before we save the model and run MODFLOW is to define the layer elevations
185. mmand from the Interpolation menu 2 Enter nn for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og Two Dimensional Geostatistics 4 11 4 17 Kriging 4 17 1 4 17 2 The last interpolation scheme we will test is kriging Kriging is based on the assumption that points that are near each other have a certain degree of spatial correlation but points that are widely separated are statistically independent Kriging is a set of linear regression routines that minimize estimation variance from a predefined covariance model 1 Select the Interp Options command from the Interpolation menu 2 Select the Kriging option 3 Select the Options button to the right of the Kriging option Creating the Experimental Variogram There are a large number of options to be specified in the Kriging Options dialog Fortunately the defaults shown are adequate in most cases However a variogram must always be defined 1 Select the Edit Variograms button 2 Select the New button in the section entitled Experimental variogram editor in the upper right section of the Variogram Editor dialog 3 Select the OK button to accept the defaults A curve should appear in the upper left window of the Variogram Editor This curve is called an experimental variogram The experimental variogram is found by calculating the variance in data set values of each scatter point in the set with respect to each of the other point
186. n assigning the attributes for these nodes you will notice that both specified head and drain attributes can be edited for the nodes To edit the drain elevation select the drain option in the list box in the lower left section of the Attributes dialog ANS IR Wi f 4 C N fj Ae agp Jp Node Elevation 1 730 aif f 696 ra 7277 692 5 730 AE ge y 4 5 SE N gt J F i Ns 2 ee Node6 Vex Hig tic tee te SNI i N UTEE Wiz TOM Figure 7 6 Elevations for Drain Nodes Building the polygons With the local sources sinks type coverage the entire region to be modeled must be covered with non overlapping polygons This defines the active region of the grid In most cases all of the polygons will be variable head polygons the default However other polygons may be used For example to model a lake a general head polygon can be used The simplest way to define the polygons is to first create all of the arcs used in the coverage and then select the Build Polygons command This command searches through the arcs and creates a polygon for each of the closed loops defined by the arcs These polygons are variable head by default but may be converted to other types by selecting the polygons and using the Attributes comma
187. n the Interpolation menu The list on the top left side of the dialog represents the data sets available in the active scatter point set The list on the top right side lists the MODFLOW layer arrays that can be interpolated to The dialog is used to associate each of the data sets with the appropriate layer arrays This is accomplished by selecting an item from each list and selecting the Map button The list at the bottom shows the relationships that have been mapped The starting head array is already mapped since the association is obvious from the names used for the data set and the array We also want to map the ground elevations to the top of layer one 1 Check to make sure that the ground_elev data set and the Top Elevations Layer 1 array are highlighted 2 Select the Map button 3 Select the OK button to perform the interpolation 7 14 4 Importing the Layer Elevation Scatter Points Next we will import the scatter points defining the layer elevations 1 Select the Import command in the File menu 2 Inthe Open dialog select the sp2 filter 3 Select the file titled elevs sp2 4 Select the Open button A second set of scatter point symbols should appear on the model 7 14 5 Interpolating the Layer Elevations To import the layer elevations 1 Select the to MODFLOW Layers command in the Interpolation menu 2 Check to confirm that the mappings are properly selected the correct mapping should be selected by
188. nd Now that all of the arcs in the coverage have been created we are ready to construct the polygons All of our polygons will be variable head polygons 1 Select the Build Polygons command from the Feature Objects menu 2 When you are asked if you wish to build the polygons using all arcs select OK 7 6 7 MODFLOW Conceptual Model Approach 7 13 Even though the polygons are created there is no visible difference in the display You can view the polygons if you wish by selecting the Display Options command in the Feature Objects menu and turning on the Polygons Fill option Creating the Wells The final step in creating the local sources sinks coverage is to define the wells Wells are defined as point type objects Two wells will be created 1 Select the Create Point tool 2 Move the cursor to the approximate location of Well 1 shown in Figure 7 1 and click once with the mouse to create the point 3 While the new point is selected type the coordinates 2741 0 4673 0 in the x and y edit fields at the top of the GMS window and hit the Tab or Enter key 4 Select the Attributes command from the Feature Objects menu 5 Select the Well option 6 Enter a constant value of 24100 0 for the flux pumping rate 7 Check to ensure that the well will be applied to layer 1 this is the default 8 Select the OK button In a similar fashion create the other well at the location 10557 0 3290 0 and assign
189. nd in the Map 17 4 1 SEEP2D Unconfined 17 3 module With this approach we simply need to define the boundaries of the problem domain and GMS automatically constructs all of the interior nodes and elements Defining a Coordinate System Before we construct the mesh we must first establish a coordinate system We will use a coordinate system with the origin at the lower left corner of the dam as shown in Figure 17 2 166 72 194 72 Figure 17 2 Coordinate System We will begin the mesh construction by creating some points at key locations in the mesh Before we create any points we must first set the window bounds so that we are viewing the proper region of the real world coordinate system in the graphics window To set the window bounds 1 Select the Set Wind Bounds command from the View menu 2 Select the X range to be specified option 3 Set X at left to 10 4 Set X at right to 370 5 Set Y at bottom to 50 6 Click on the OK button We also need to set up a drawing grid to help us place the points in the proper location To set up the drawing grid 1 Select the Drawing Grid Options command from the Display menu 2 Set the Grid spacing to 2 3 Turn on the Snap to grid option 4 Click on the OK button 17 4 GMS Tutorials As you move the cursor across the graphics windows you should see the cursor position updated in intervals of two feet in the lower left window 17 4 2 Creating a Coverag
190. ne of the triangle shaped symbols 5 Select the OK button to exit the Symbol Picker dialog 6 Select the OK button to exit the Display Options dialog Each of the points should now be displayed with a colored triangle The color of the symbol represents the relative concentration of the contaminant at the point When displaying colored symbols it is useful to also display a color legend 1 Select the Color Ramp Options command from the Data menu 2 Turn on Show Color Legend option 3 Select the OK button Notice that the concentrations vary from zero to about 100 0 4 5 Creating a Bounding Grid The goal of this tutorial is to generate a series of contour plots illustrating the plume To do this we will first create a grid that bounds the scatter point set and then we will interpolate the concentrations from the scatter points to the grid nodes The grid will then be contoured To create the grid 4 4 GMS Tutorials 1 Select Bounding Grid from the Scatter Points menu Notice that the x and y dimensions of the grid are already defined The default values shown in the dialog cause the grid to extend beyond the scatter points by 10 on each side 2 Enter 60 for the number of cells in the x direction 3 Enter 40 for the number of cells in the y direction 4 Select the OK button 5 Select the OK button to accept the default z value A grid should appear on the screen that just encompasses the scatter point set 4 6
191. ned condition are described in the following chapter The two SEEP2D tutorials are entirely independent and can be completed in any order However it is recommended that the first tutorial be completed before the second tutorial since the motivation behind many of the steps in the model definition process is described in more detail in the first tutorial Description of Problem The problem we will be solving in this tutorial is shown in Figure 16 1 16 2 GMS Tutorials Sheet Pile Clay Blanket 32 ft Silty Sand ky ky 100 Figure 16 1 Confined Flow Problem The problem involves a partially penetrating sheet pile wall with an impervious clay blanket on the upstream side The sheet pile is driven into a silty sand deposit underlain by bedrock at a depth of 32 feet From a SEEP2D viewpoint this problem is a confined problem For SEEP2D a problem is confined if it is completely saturated A problem is unconfined if it is partially saturated 16 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 16 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 2D Mesh module H e The SEEP2D interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting th
192. ner 17 4 17 4 4 Creating the Ea bs 17 5 17 4 5 Redistributing Vertice saen eare E TOTEE 17 6 17 4 6 Creating the POLY BONS E a a eaa tubes Sa OKTE ti 17 6 17 4 7 Assigning the Material sianet aaia raa E a i a 17 6 17 4 8 Constructing the Mesh EA A E RO A 17 7 1775 RENUMBERING THE 17 7 17 6 INITIALIZING THE SEEP2D SOLUTION ccccssscccececeesssccecececsessasececececseseaccecececeeseaeaecececsensnseaeees 17 8 17 7 SETTING THE ANALYSIS OPTIONS ccseccccccecsesessscecececeesesececececseneseseseeececsessaaeceeeceesesnsaeeeeseeesensaaeees 17 8 17 8 ASSIGNING MATERIAL PROPERTIES c cccccccsesessscecececeesesececececsesensesececcceesesseaeeeeeceesesssaeeeeeeseeensaaeees 17 8 17 9 ASSIGNING BOUNDARY CONDITIONS cccccceessssscecececeenssececececeeseseaeceesceeseaaeceeeceesesaeseeeeeeeeesaaeees 17 9 17 9 1 Specified Head Boundary 17 9 17 9 2 Exit Face Boundary 17 10 17 10 SAVING THE SIMULATION 17 10 A 5 2 a e 17 11 17 12 VIEWING THE SOLUTION 17 11 17 13 MODELING FLOW IN THE UNSATURATED
193. nodes and change the coordinates using the edit fields in the top window Highlight the values in the edit fields with the cursor type in a new value and hit the Enter key You can also select nodes and delete them using the Delete key on the keyboard or the Delete command in the Edit menu SEEP2D Confined 16 5 Once you have created the nodes you can center the display as follows ak Select the Frame Image macro A F We will now turn the drawing grid off since it is no longer needed 1 Select the Drawing Grid Options command from the Display menu 2 Turn off the Snap to grid option 3 Click on the OK button The nodes you have created should resemble the nodes shown in Figure 16 3 without the labels Figure 16 3 Nodes Created with the Create Node Tool 16 4 3 Interpolating Intermediate Nodes The next step in the mesh creation process is to add some new nodes between the nodes we just created This will be accomplished using the nterpolate Nodes command 1 Choose the Select Nodes tool in the Tool Palette 2 Select nodes D and E This can be accomplished by selecting node D and holding down the Shift key while selecting node E or by dragging a box around nodes D and E 3 Select the Node Interp Options command in the Modify Mesh menu 4 Make sure that the Number of intervals in string option is selected 5 Enter 2 for the number of intervals This will create one new node between the two selected nodes
194. nt that plots on or near the diagonal line indicates a low error Points far from the diagonal have a larger error To determine which symbol goes with which point Click on one of the symbols in the Computed vs Observed plot in the Plot Window Notice that the observation point corresponding to the symbol was selected in the Graphics Window Also notice that the calibration statistics for the point are displayed in the Help Window Error Summary In the Error Summary three types of error norms are reported The mean error is simply the average error for the points This value can be misleading since positive and negative errors can cancel The mean absolute error is the average of the absolute values of the errors This value is more representative of the average error of all the points since positive and negative errors do not cancel each other The root mean square error is the square root of the mean of the errors squared This error norm tends to give more weight to cases where a few extreme error values exist 14 10 Editing the Hydraulic Conductivity The next step in the calibration exercise is to change the model parameters and re run the model Note that the errors on the left and right side of the model are mostly red and negative This indicates that the observed value is much larger than the current computed value We will begin by changing the hydraulic conductivity in these zones The hydraulic conductivity will be edit
195. nt to a new location 10 22 Conclusion This concludes MT3DMS Conceptual Model Approach tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt 11 SEAM3D 11 1 Descri SEAM3D is a reactive transport model used to simulate complex biodegradation problems involving multiple substrates and multiple electron acceptors It is based on the MT3DMS code In addition to the regular MT3DMS modules SEAM3D includes a Biodegration package and NAPL Dissolution package This tutorial illustrates how to use both of these packages to set up a reactive transport simulation iption of Problem The problem we will be solving in this tutorial is illustrated in Figure 11 1 The site represents a shallow unconfined aquifer with a uniform flow field from left to right A NAPL plume is located on the left side of the model The NAPL plume contains two primary hydrocarbons benzene and toluene The benzene and toluene are dissolving into the ground water and are being transported to the right We will set up a SEAM3D simulation that models the transport and sequential degradation of the contaminants via aerobic degradation and sulfate reduction over a 2000 day period The model will include dispersion and retardation due to sorption The reactions will be modeled using the Biodegradation package The gradual release of contaminants from the NAPL plume will be model
196. ntually the image should appear Now that the image is imported it will appear each time the screen is refreshed All other objects are drawn on top of the image The image only appears in plan view You are actually viewing only a portion of the complete TIFF image It is possible to pan and zoom and resample the TIFF image to view a different region or to view at a different resolution More information on manipulating TIFF images can be found in the GMS Reference Manual 7 4 2 Image File vs TIFF File The project you just opened included a file called an image file It is not the file containing the TIFF image The TIFF file is called easttex tif and 15 located in the same directory as the image file When a TIFF file is first imported it must be registered Registering a TIFF file involves selecting three points on the image and entering the real world coordinates of those points These points are used to stretch and position the image when it is drawn on the screen so that it is drawn in the correct location Once a TIFF image is registered the registration data and the name of the TIFF file are saved to an image file From that point on the TIFF image can be imported and registered in one easy step by opening the image file The image we are using in this tutorial was registered previously and the registration data were saved to a file named start img when the project was saved Feature Objects We are now ready to begin constructin
197. o view the answer a map file can be imported which contains a set of parameter values which result in a solution that satisfies the calibration target for each of the ten observation wells Before reading in the new conceptual model you must first delete each of the three MODFLOW coverages H 1 Switch to the Map module 2 Select the Coverages command in the Feature Objects menu 3 Highlight and delete each of the three MODFLOW coverages Sources amp Sinks Recharge and Hydraulic Conductivity 4 Select the OK button To read in the new conceptual model 1 Select the Open command in the File menu 2 Select No at the prompt to confirm we don t want to save our changes 3 Select the file titled answer map 4 Select the Open button You can now convert this model to the grid and compute a new solution using the steps described above 14 16 Conclusion This concludes the Model Calibration tutorial If you wish to exit GMS at this time 3 Select the Exit command from the File menu 4 Select No at the prompt 15 FEMWATER Flow Model FEMWATER 15 a three dimensional finite element ground water model It can be used to simulate flow and transport in both the saturated and the unsaturated zone Furthermore the flow and transport can be coupled to simulate density dependent problems such as salinity intrusion This tutorial describes how to build a FEMWATER model to simulate flow only 15 1 Des
198. objects in the conceptual model We will then create three triangulated irregular networks TINs one for the top terrain surface one for the bottom of the upper aquifer and one for the bottom of the lower aquifer We will then create the 3D elements by extruding each of the elements in the 2D mesh into a column of 3D elements 15 8 GMS Tutorials 15 5 1 Defining the Materials 15 5 2 Before building the mesh we will define a material for each of the aquifers The materials are assigned to the TINs and eventually to each of the 3D elements 1 Select the Materials command from the Edit menu 2 Change the name of the default material to Upper Aquifer 3 Click on the color window in the Display section and change the material color to green 4 Select the New button to create another material 5 Change the name of the new material to Lower Aquifer 6 Change the material color to red 7 Select the OK button Building the 2D Projection Mesh 15 5 3 The 2D projection mesh can be constructed directly from the conceptual model 1 Select the Map gt 2D Mesh command from the Feature Objects menu 2 Select OK to accept the defaults in the Map gt 2D Mesh dialog After a few seconds the mesh should appear Building the TINs To build the TINs defining the stratigraphic horizons we will make three TINs where each TIN is a copy of the 2D mesh At first these three TIN s will have the same ele
199. oints along the vertical traces are significantly smaller than the distances between scatter points along the horizontal plane This disparity in scaling causes clustering and can be a source of poor results in some interpolation methods The effects of clustering along vertical traces can be minimized using the z scale option in the Interpolation Options dialog The z coordinate of each of the scatter points is multiplied by the z scale parameter prior to interpolation Thus if the z scale parameter is greater than 1 0 scatter points along the same vertical axis appear farther apart than they really are and scatter points in the same horizontal plane appear closer than they really are As a result points in the same horizontal plane are given a higher relative weight than points along the z axis This can result in improved accuracy especially in cases where the horizontal correlation between scatter points is expected to be greater than the vertical correlation which is typically the case due to horizontal layering of soils or due to spreading of the plume on the top of the water table To change the z scale option 1 Switch to the 3D Scatter Point module 2 Select the Interp Options command from the Interpolation menu 3 Change the z scale value to 8 0 4 Select the OK button 5 Select the to 3D Grid command from the Interpolation menu 6 Enter idw_const2 for the new data set name 7 Select the OK button 8 Select
200. olor legend option 8 Select the OK button 9 Select the Fringe Options command from the Data menu 10 Select the Color fringe specified range option 5 12 GMS Tutorials 11 Enter 1000 0 for the Minimum fringe value 12 Enter 15000 0 for the Maximum fringe value 13 Select the OK button 5 17 2 Setting up the Film Loop To set up the film loop 1 2 Select the Film Loop command from the Data menu Select the Setup button Turn on the Animate cutting plane option Turn on the Z cutting plane Select the OK button 5 17 3 Playing Back the Film Loop You should see some images appear on the screen These are the frames of the film loop which are being generated Once they are all generated you can play them back at a high speed When the hourglass cursor disappears Select the Play gt button to begin the animation You may wish to experiment with some of the other playback options After viewing the animation select the Stop button to stop the animation 5 18 Setting up a Moving Iso Surface Film Loop Another effective way to visualize the plume model is to generate a film loop showing a series of iso surfaces corresponding to different iso values To set up the film loop 1 Select the Setup button in the Film Loop dialog 2 Turn off the Animate cutting plane option 3 Turn on the Animate iso surface option 4 Enter 1000 0 for the Begin value Three Dimensional Geostatistics 5 13
201. ompt to delete the mesh You should now see a plot of the flow net To better view the flow net we will turn off the display of nodes and elements 1 Select the Display Options command from the Display menu 2 Turn off the Nodes and Elements options 3 Turn on Mesh boundary option 4 Select the OK button Note that there are only a small number of flow lines GMS determines the number of flow lines to display based on how closely spaced the equipotential lines are in one of the materials By default the interval is computed based on the Shell material To base the number on the Core material 1 Select the Display Options command from the Display menu 17 12 GMS Tutorials 2 Select the SEEP2D tab 3 Select the Base Material button 4 Select the Core material 5 Select the OK button to exit the dialog 17 13 Modeling Flow in the Unsaturated Zone For the last stage of the tutorial we will compute a solution using a different approach Rather than deforming the mesh and computing the solution in the saturated zone only we will compute the flow in both the saturated and the unsaturated zone 17 13 1 Reading in the Original Model Before making the required changes to the model we need to read the undeformed model back into memory 1 Select the Read Simulation command from the SEEP2D menu 2 Select No at the prompt to confirm we don t want to save changes 3 Select the file entitled dam1 sps 4 Select
202. on is adjusted to match the bedrock elevation 1 Select the Truncate to bedrock option 2 Select the Fix Affected Layers button 3 Exit both dialogs 12 12 GMS Tutorials 12 10 5 Viewing the Corrected Layers Notice how the outcropping is now properly modeled To view the cross sections 1 Use the arrow buttons in the Mini Grid Display to view the grid along different columns 2 Select the View J Axis macro S 3 Use the arrow buttons to view the grid along different rows Next we will switch to plan view and see how the cells on the perimeter of the grid have been made inactive K 1 Select the View K Axis macro 2 Use the arrow buttons to view the grid on different layers Finally we will view the grid in general mode to see a 3D plot of the stratigraphy 1 Select the General Mode command in the View menu 2 Select the Oblique View macro leg 3 Select the Shade macro Og F You may wish to use the Rotate tool to view the grid from different viewpoints 12 11 Conclusion This concludes the Defining Layer Data tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt 13 Regional to Local Model Conversion For many modeling studies determining an appropriate set of boundary conditions can be difficult It is often the case that classical boundaries such as rock outcroppings rivers lak
203. ons However once the drains are defined it is often easier to edit the values using the Drain Package dialog 1 Select the Drain Package command from the MODFLOW menu 2 Enter the following values for the elevations of the drains 3 Select the OK button 6 11 The Well Package Next we will define several wells by selecting the cells where the wells are located and using the Point Sources Sinks command 6 11 1 Top Layer Wells Most of the wells are in the top layer but some are in the middle and bottom layers We will define the wells in the top layers first 1 While holding down the Shift key select the following cells These cells are shown in Figure 6 3 2 Select the Point Sources Sinks command from the MODFLOW menu 6 12 GMS Tutorials 6 11 2 3 Inthe Well section select the Add button 4 Enter a Flow value of 432000 the minus sign signifies extraction 5 Select the OK button 6 Unselect the cells by clicking anywhere outside the grid L Constant Head Cells Pe a Drain Cells A m Select these cells X Figure 6 3 Cells to be Selected on Top Layer Middle Layer Wells Next we will define some wel
204. option Select the Times button 11 6 GMS Tutorials 11 6 6 11 6 7 4 Select the Initialize Values button 5 Enter 100 for the Initial time step size 6 Enter 100 for the Maximum time step size 7 Enter 2000 for the Maximum simulation time 8 Select the OK button to exit the Initialize Time Steps dialog 9 Select the OK button to exit the Variable Time Steps dialog 10 Select the OK button to exit the Output Control dialog Entering the Porosity requires a porosity value for each cell in order to compute a correct seepage velocity for transport We will use a constant porosity for the entire grid To enter the porosity 1 Select the Porosity button 2 Select the Constant gt Grid button 3 Enter a value of 0 25 and select OK 4 Select the OK button to exit the Porosity dialog Starting Concentrations The mobile species are listed in the lower right corner of the BTN Package dialog We must define a set of starting concentrations for each of the species The default concentration is zero This will be the correct starting concentration for the hydrocarbon substrates and the tracers However we must set the starting concentrations of the O2 SO4 and H2S to the correct background values 1 Select O2 in the list and select the Starting Concentration button 2 Select the Constant gt Grid button 3 Enter a value of 4 0 mg L and select the OK button 4 Select the OK button to exit the S
205. ort the points 1 Select the Jnport command from the File menu 2 Open the file entitled case2 sp2 Interpolating the Values To interpolated the values from the new scatter points 1 Select the to MODFLOW Layers command from the Interpolation menu 2 Select the OK button Note how the middle layer becomes inverted on the right side of the model Correcting the Layer Data The next step is to fix the overlap on the right side of the model using the layer data tools in the MODFLOW model checker 1 Switch to the 3D Grid module 2 Select the Check Simulation command in MODFLOW menu 3 Select the Run Check command 4 Scroll down to where the errors for the BCF package are shown Note that a set of layer elevation errors are shown 5 Select the Fix Layer Errors button The Fix Layer Errors dialog provides several options for correcting layer errors Notice that several errors are listed for layer 2 The correction options are shown on the left For this case we will use the Average option This method computes the average of the top and bottom elevation for each cell and moves the top elevation to be just above the average and the bottom elevation to be just below the average The final difference between the top and the bottom is set to the Minimum thickness value shown in the dialog 1 Select Layer 2 in the list on the right side of the dialog 12 8 GMS Tutorials 2 Select the Average option 3 Select the F
206. our problem the constant head values are zero Since all of the starting head values are already zero by default we don t need to make any changes Select the OK button to exit the Starting Heads dialog 6 6 GMS Tutorials 6 6 6 Exiting the Dialog This completes the input for this dialog Select the Close button to exit the MODFLOW Basic Package dialog 6 7 Assigning IBOUND Values Directly to Cells 6 7 1 6 7 2 6 7 3 As mentioned above the IBOUND values can be entered through the IBOUND Array dialog In some cases it is easier to assign values directly to cells This can be accomplished using the Cell Attributes command Before using the command we must first select the cells in the leftmost column of the top two layers Viewing the Left Column To simplify the selection of the cells we will change the display so that we are viewing the leftmost layer Choose the View the J Axis macro ci Notice that we are now viewing column number one the leftmost column Selecting the Cells To select the cells 1 Choose the Select Cells tool 2 Drag around all of cells in the top two layers of grid Changing the IBOUND Value To edit the IBOUND value 1 Select the Cell Attributes command from the MODFLOW menu 2 Enter a value of 1 for the BOUND value 3 Select the OK button to exit the Cell Attributes dialog 4 To unselect the selected cells click anywhere in the G
207. p 4 Select the file entitled obswells map 5 Select the Open button 14 8 Entering the Observed Stream Flux Now that the observation points are defined we will enter the observed flux in the stream Observed fluxes are assigned directly to arcs and polygons in the local source sink coverage of the conceptual model We will assign an observed flux to the river arcs When we read in a solution GMS will parse through the CCF file and automatically calculate the computed flux to the stream This flux value will be compared to the observed flux GMS provides two methods for assigning observed flux to individual arcs or to a group of arcs The stream flow that was measured at the site represents the total stream flow at the stream outlet at the top of the model This flow represents the flux to the stream for the entire stream network Thus we need to assign the observed flux to a group of arcs When reading a solution GMS will then automatically sum the computed flux for all arcs in the group Before assigning the observed flux we must first create an arc group 1 In the Coverage combo box at the top of the window select the Sources amp Sinks coverage 2 Select the Select Arcs 1001 3 While holding down the Shift key click on each of the river arcs 4 Select the Create Arc Group command from the Feature Object menu This creates a new object out of the selected objects We can now assign an observed flux to the arc group
208. ply by pointing and clicking 2m 1 Select the Plan View macro tise 2 Select the Create Vertex tool 3 Place the cursor in the interior of one of the triangles in the TIN and create a vertex by clicking the mouse button A dialog appears prompting for the z value of the new vertex The default value is computed using a linear interpolation of the surrounding vertices Select the OK button to accept the default value Notice that the vertex was automatically incorporated into the TIN topology In addition the vertex is selected and can be edited using the edit fields in the Edit Window 2 13 Deleting Vertices It is also frequently necessary to delete vertices To delete the vertex you just created Surface Modeling With TINs 2 7 1 Select the Delete command from the Edit menu 2 Select OK to confirm the deletion Notice that all of the triangles connected to the vertex were deleted By default this is what happens when a vertex is deleted The resulting void can be filled with triangles by using the Create Triangle tool to manually create triangles However another option is available for deletion that causes the region surrounding a deleted vertex to be automatically retriangulated 1 Select the Vertex Options command from the Modify TIN menu 2 Turn on the option entitled Retriangulate after deleting 3 Select the OK button 4 Choose the Select Vertices tool 5 Select one the vertices in the interio
209. point set representing values such as contaminant concentration porosity hydraulic conductivity etc The 3D scatter point set we will import and use with this tutorial has previously been entered into a text file using the Tabular Scatter Point File format To read the scatter point file 1 Switch to the 3D Scatter Point module 1 2 Select the Import command from the File menu 3 Inthe Open dialog change the filter to 5 3 4 Open the directory entitled tutoria geos3d 5 Select the file entitled tank sp3 6 Click on the Open button z 7 Select the Oblique View macro lee A set of points should appear on the screen Notice that the points are arranged in vertical columns This hypothetical set of points is meant to represent a set of measurements of contaminant concentration in the vicinity of a leaky underground storage tank Each column of points corresponds to a borehole or the path of a penetrometer along which concentrations were measured at uniform intervals The goal of the tutorial is to use the tools for Three Dimensional Geostatistics 5 3 3D geostatistics in GMS to interpolate from the scatter points to a grid and generate a graphical representation of the plume 5 4 Displaying Data Colors Next we will change the display options so that the color of each point is representative of the concentration at the point 1 2 6 Select the Display Options command in the Display menu Turn on the Data co
210. process is to interpolate the regional data from the scatter points to the MODFLOW layer arrays 1 Switch to the 2D Scatter Point module 2 Select to MODFLOW Layers command from the Interpolation menu 3 At the bottom of the dialog select the Apply starting head to all cells option 4 Select the OK button 13 9 Saving and Running the Local Model We are now ready to save the MODFLOW model and run the simulation 1 Switch to the 3D Grid module E 2 Select the Save As command from the MODFLOW menu 3 Change the filename to locmod mfs 4 Select the Save button To run MODFLOW 1 Select the Run MODFLOW command from the MODFLOW menu 2 Select OK at the prompt 3 When the simulation is finished close the window and return to GMS 13 10 Viewing the Results Finally we will read in the computed head values for the local model 1 Select the Read Solution command from the MODFLOW menu 2 Select OK at the prompt 3 Once again zoom in on the grid 13 10 GMS Tutorials Once the file is finished reading you should see a set of head contours that closely resemble the head contours from the regional model At this point the local flow model is complete and the injection and extraction wells could be added for the pump and treat simulations 13 11 Conclusion This concludes the Regional to Local Model Conversion tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2
211. r of TIN 6 Select the Delete command from the Edit menu 7 Select OK to confirm the deletion Notice that the triangles next to the deleted vertex are deleted but the resulting void is retriangulated 2 14 Smoothing a TIN 2 14 1 As mentioned above a TIN represents a piecewise linear surface If the vertices defining the TIN are sparse the linear surface defined by the triangles may appear excessively irregular A TIN can be smoothed in GMS by copying the TIN vertices to a scatter point set subdividing the TIN into a denser set of triangles and interpolating the elevations to the new vertices in the TIN The resulting TIN is still piecewise linear but it appears much smoother since the triangles are smaller Deleting the TIN We will now go through an example of TIN smoothing but first we will read in a different TIN since we have made several changes to this TIN 1 Select the Delete All command from the Edit menu 2 Select OK to confirm the deletion 2 8 GMS Tutorials 2 14 2 2 14 3 2 14 4 3 Select the Open command from the File menu 4 Select No at the prompt about saving the project 5 Inthe Open dialog select the tin filter 6 Select the file entitled sparse tin 7 Click on the Open button Copying the Vertices The first step in smoothing the TIN is to copy the vertices of the TIN to a scatter point set This will allow us to use the scatter point set later to interpolate the z valu
212. raphics Window outside the grid E 5 Select the View the K Axis macro a 6 7 4 MODFLOW Grid Approach 6 7 Notice that a symbol is displayed in the cells we edited indicating that the cells are constant head cells Checking the Values To ensure that the IBOUND values were entered correctly 1 Select the Basic Package command from the MODFLOW menu 2 Select the BOUND button 3 Choose the up arrow to the right of the layer field in the upper left corner of the dialog to cycle through the layers Notice that the leftmost column of cells in the top two layers all have a value of 1 Most of the MODFLOW input data can be edited in GMS using either a spreadsheet like dialog such as this or by selecting a set of cells and entering a value directly whichever is most convenient 1 Select the OK button to exit the BOUND Array dialog 2 Select the Close button to exit the MODFLOW Basic Package dialog 6 8 BCF Package 6 8 1 6 8 2 The next step in setting up the model is to enter the data for the block centered flow BCF package The BCF package is required for all simulations The block centered flow package computes the conductances between each of the grid cells and sets up the finite difference equations for the cell to cell flow To enter the BCF data Select the BCF Package command from MODFLOW menu Layer Types The options on the right side of the dialog are used to define the layer type and
213. rc create the arc by clicking points along the creek bed and end the arc by double clicking on the top arc Notice that when you click in the vicinity of a vertex on an existing arc or on the edge of an arc GMS automatically snaps the arc you are creating to the existing arc and makes a node at the junction of the two arcs Create the arcs labeled arc 2 and arc 3 in Figure 7 5 the same way you made arc 1 MODFLOW Conceptual Model Approach 7 11 Figure 7 5 The Drain Arcs Next we will define the arcs as drains and assign the conductance and elevation to the arcs 6 Select the Select Arcs 1001 MM Select all of the drain arcs by clicking on the arcs while holding down the Shift key Select the Attributes command in the Feature Objects menu Select the Drain option Enter a conductance of 6000 0 This represents a conductance per unit length value GMS automatically computes the appropriate cell conductance value when the drains are assigned to the grid cells Select the OK button The elevations of the drains are specified at the nodes of the arcs The elevation is assumed to vary linearly along the arcs between the specified values 1 2 Select the Select Points Nodes tool Ae Double click on each of the nodes at the end points of the arcs and assign the elevations as shown in Figure 7 6 7 12 GMS Tutorials 7 6 6 Nodes 2 4 amp 6 are connected to both drain and specified head arcs Whe
214. re restored to the default state 9 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module e The MODFLOW interface e The MT3DMS interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS MT3DMS Grid Approach 9 3 you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 9 4 Building the Flow Model Before setting up the MT3DMS simulation we must first create a MODFLOW simulation The resulting MODFLOW solution will then be used as the flow field for the transport simulation If you are already familiar with how to create a flow model and would like to skip this section you can read in a flow model that has already been prepared Otherwise continue through section 9 4 To skip this section and read in a flow model that has already been prepared 1 Select the Open command from the File menu 2 Locate and open the directory entitled tutorialwnt3dgrid sample 3 Select the file entitled flowmod mfs 4 Choose the Open button 5 Switch to the 3D Grid module 6 Skip ahead to section 9 5 9 4 1 Creating t
215. rlain by limestone bedrock which outcrops to the hills at the north end of the site There are two primary sediment layers The upper layer will be modeled as an unconfined layer and the lower layer will be modeled as a confined layer The boundary to the north will be a no flow boundary and the remaining boundary will be a specified head boundary corresponding to the average stage of the rivers We will assume the influx to the system is primarily through MODFLOW Conceptual Model Approach 7 3 recharge due to rainfall and run on There are some creek beds in the area which are sometimes dry but occasionally flow due to influx from the groundwater We will represent these creek beds using drains There are also two production wells in the area that will be included in the model NOTE Although the site modeled in this tutorial is an actual site the landfill and the hydrogeologic conditions at the site have been fabricated The stresses and boundary conditions used in the simulation were selected to provide a simple yet broad sampling of the options available for defining a conceptual model 7 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 7 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module He e T
216. rner of the screen locate the region of the mesh representing the top of the sheet pile Recall that this is the location where we defined two nodes very close to each other The coordinates of the nodes are 90 32 and 90 25 32 Select the Zoom tool ca Drag a box that just encloses the nodes at the top of the sheet pile and all of the nodes on the top boundary to the right of the sheet pile Zooming in this manner will make it easier to select the proper nodes Choose the Select Nodes tool Click on the node on the right at the top of the sheet pile the node with coordinates 90 25 32 Holding down the Shift key this ensures that the node you just selected remains selected drag a box that encloses all of the nodes on the top boundary to the right of the node you just selected Do not enclose the node you just selected Select the Node BC command from the SEEP2D menu Select the Head option and enter a value of 32 Select the OK button ak Select the Frame Image macro A F 16 10 Saving the Simulation We are now ready to save the simulation 1 2 Select the Save As command from the SEEP2D menu Locate and open the directory entitled tutorial s2con Enter blanket sps for the file name Select the Save button 16 14 GMS Tutorials 16 11 Running SEEP2D To run SEEP2D 1 Select the Run SEEP2D command from the SEEP2D menu 2 Select the OK button At this point SEEP2D is launched in a new window
217. roblem the starting concentrations are all zero and the default is adequate HTOP and Thickness Arrays MT3DMS uses the HTOP array and a thickness array to determine the layer geometry However the values for these arrays are determined automatically from the MODFLOW layer data and no input is necessary Porosity Array Finally we will define the porosity for the cells Our problem has a constant porosity of 0 3 This is the default value in GMS so no changes need to be made This completes the definition of the Basic Transport package data Select the Close button to exit the Basic Transport Package dialog 9 5 3 The Advection Package The next step is to enter the data for the Advection package 1 Select the Advection Package command from the MT3D menu 2 For the Solution scheme select the Third order TVD scheme ULTIMATE option 3 Select the OK button 9 5 4 The Dispersion Package Next we will enter the data for the Dispersion package 1 Select the Dispersion Package command from the MT3D menu 9 12 GMS Tutorials Select the Longitudinal Dispersivity button Select the Constant gt Grid option Enter a value of 20 Select the OK button Select the OK button to exit the Longitudinal Dispersivity dialog Enter a value of 0 2 for the Ratio of trans dispersivity to long dispersivity parameter Enter a value of 0 2 for the Ratio of vert dispersivity to long dispersivity parameter Select the Close
218. s Next we will select the packages Select the Packages button The packages dialog is used to specify which of the packages we will be using to set up the model The Basic package is always used and therefore it cannot be turned off To select the other packages 1 Select the Recharge package 2 Select the Drain package 3 Select the Well package 4 Inthe Solver section select the Strongly Implicit Procedure package 5 Select the OK button to exit the Packages dialog Units At this point we can define the units used in the model The units we choose will be applied to edit fields in the GMS interface to remind of the proper units for each parameter 1 Select the Units button 2 Enter ft for the length unit and d for the time unit We will ignore the other units they are not used for flow simulations 3 Select the OK button 6 6 4 MODFLOW Grid Approach 6 5 The IBOUND Array 6 6 5 The next step is to set up the IBOUND array The IBOUND array is used to designate each cell as either active IBOUND gt 0 inactive IBOUND 0 or constant head IBOUND lt 0 For our problem all cells will be active except for the first two layers in the leftmost column which will be designated as constant head Select the BOUND button The JBOUND dialog displays the values of the IBOUND array in a spreadsheet like fashion one layer at a time The edit field in the upper left corner of the dialog can be used
219. s see Figure 3 3 the lower blue red contact on hole 8G the bottom of hole 6G the blue red contact on hole 7G the lower blue red contact on hole 5G and the bottom of hole 2G 2 Select the Contacts gt TIN command from the Borehole menu 3 Select the Auto extrapolate with trimming to selected boreholes option 4 Select the OK button 5 Enter botblue2 for the name of the TIN 6 Select the OK button Z Le X Figure 3 3 Contacts to be Selected 3 12 GMS Tutorials 3 11 3 Hiding the TINs To hide the TINs 1 Switch to the TIN module 2 Choose the Select tool 08 3 While holding down the Shift key select the two TINs you just created es 4 Select the Hide macro ii 3 12 Constructing the Red Solid 3 12 1 3 12 2 Now that all of the TINs are constructed we are ready to construct the solid models from the TINs To begin we will construct the solid representing the red soil This solid will be constructed by extruding the boundary of the red TIN down to a horizontal plane below the boreholes Creating the Solid To create the solid 1 Select the TIN entitled topred 2 Select the Extrude TIN gt Solid command from the Build TIN menu 3 Enter red for the name of the solid 4 Enter 45 0 for the Elevation 5 Select the OK button Shading the Solid A solid should appear on the screen The shape of the solid can be better illustrated by genera
220. s and enter the same set of values 0 1 4400 110 10 Select OK to exit the NAPL Dissolution Package dialog SEAM3D 11 11 11 12 Biodegradation Package The last package to set up is the Biodegradation package We will enter the yield coefficients inhibition coefficients and other reaction parameters controlling the degradation of benzene and toluene Select the Biodegradation Package command from the MT3D menu 11 12 1 Minimum Concentrations Notice that the input for the dialog is broken up into a series of property sheets First we will enter the data for the minimum concentrations section 1 2 Select the Min Conc tab Enter 2 for the Number of bio steps per transport step Enter 0 001 for the Microcolony minimum concentration Select Benzene from the text window and enter 0 01 for the Minimum concentration Select Toluene from the text window and enter 0 05 for the Minimum concentration Select O2 from the text window and enter 0 1 for the Minimum concentration Select SO4 from the text window and enter 0 2 for the Minimum concentration 11 12 2 Electron Acceptor Coefficients Next we will enter the electron acceptor data 1 2 3 Select the El Acc tab in the dialog Enter 0 5 for the Inihibition coefficient for SO4 O2 Select each item in the lower text window and enter the following values for the Yield coefficient O2 Benzene 0 5 O2 Toluene 0 4 SO4 Benzene 0 15 O04 Toluene
221. s and plotting the variances versus distance between the points As can be seen in the plot of the experimental variogram the shape of the variogram indicates that at small separation distances the variance is small In other words points that are close together have similar data values With many data sets after a certain level of separation the variance in the data values becomes somewhat random and the variogram oscillates about a value corresponding to the average variance However with concentration data many of the points have zero values and this tends to pull the experimental variogram back down Creating the Model Variogram Once the experimental variogram is computed the next step is to define a model variogram A model variogram is a simple mathematical function that models the trend in the experimental variogram The model variogram is used in the kriging computations 4 12 GMS Tutorials 1 Select the New button in the section entitled Nested structure specification in the lower right corner of the Variogram Editor 2 In the section entitled Model functions on the left side of the dialog select the Gaussian option 3 In the section entitled Model parameters enter a value of 1965 0 for the Contribution and a value of 63 0 for the Range Select the Tab key after entering each value At this point there should be a reasonable fit between the model and first part of the experimental variogram The second part is difficult
222. s by dragging a rectangle that surrounds the east well 3 Delete the particles by selecting the Backspace key or selecting the Delete command from the Edit menu 4 Select OK at the first prompt 5 Select OK at the second prompt 8 12 3 Defining the New Starting Locations Finally we will create a new set of starting locations at the site of the proposed landfill The particles will be placed on the top of the ground water table to simulate leachate entering from the surface Before selecting the cells we will make the recharge coverage the active coverage so that the landfill polygon is clearly visible 1 In the Coverages combo box at the top of the window select the Recharge coverage To select the cells il 1 Select the Select Cells tool AE 2 Select the cells covered by the landfill by dragging a rectangle that coincides precisely with the landfill boundary 3 Select the Generate Particles command in the MODPATH menu 4 Select the Distribute starting points on w t surface option 5 Select the OK button 6 Click anywhere outside the grid to unselect the cells 8 8 GMS Tutorials 8 13 Saving the Simulation We are now ready to save the new simulation 1 Select the Save As command in the MODPATH menu 2 Change the file name to path2 rsp 3 Select the Save button 8 14 Running MODPATH Using the same steps you followed above execute MODPATH and compute a solution with the path2 rsp response file
223. s of hydraulic conductivity The bottom elevations for the aquifer will be defined by interpolating from a set of observation well measurements Point Node Vertex Arc Polygons Figure 7 2 Feature Objects Building the Local Source Sink Coverage The first step in building the conceptual model is to construct the local sources sinks coverage This coverage defines the boundary of the region being modeled and it defines local sources sinks including wells rivers drains and general head boundaries Coverages in GMS are assigned a coverage type corresponding to the intended use of the coverage The attributes which can be assigned to the feature objects in a coverage depend on the coverage type When GMS is first 7 6 GMS Tutorials 7 6 1 7 6 2 launched a default empty coverage is created This coverage is a general type coverage Before creating the feature objects we will change the coverage type to a local source sink type H Switch to the Map module Select the Coverages command in the Feature Objects menu Change the Default elevation to 700 This elevation is assigned to all new objects and affects how the objects are displayed in oblique view Change the name of the coverage from default coverage to Sources Sinks Change the Coverage type to MODF MT3D MODP Select the Options button Check to ensure that the coverage type is MODF MT3D local sources sinks this should be the default MODFLO
224. s to have a value of zero 1 Switch to the 3D Scatter Point module 1 2 Select the Interp Options command in the Interpolation menu 3 Turn on the Truncate values option 4 Select the Truncate to min max of active data set option Three Dimensional Geostatistics 5 11 5 Select the OK button To interpolate to the grid 1 Select the to 3D Grid command from the Interpolation menu 2 Enter idw_quad_trunc for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og Notice that the minimum value listed in the color legend is zero 5 17 Setting up a Moving Cross Section Film Loop 5 17 1 It is possible to create several cross sections at different locations in the grid to illustrate the spatial variation of the plume This process can be automated using the Film Loop utility in GMS A film loop animation can be generated showing a color shaded cross section moving through the grid Display Options Before setting up the film loop we will first delete the existing cross section turn off the color legend and reset the fringe range 1 Switch to the 3D Grid module 2 Select the Select Cross Sections tool Fadl 3 Select the cross section by clicking on the diamond shaped symbol displayed on the cross section 4 Select the Delete command from the Edit menu 5 Select the OK button to confirm the deletion 6 Select the Color Ramp Options command from the Data menu 7 Turn off the Show c
225. sections can be cut anywhere on the model and hidden surface removal and shading can be used to generate highly realistic images of either the cross sections or the solids Volumes of solids can also be computed In this tutorial you will learn how to construct a set of solid models representing soil stratigraphy using borehole data as input Since TINs are used in the construction of solids you should first complete the tutorial entitled Surface Modeling with TINs Chapter 2 before beginning this tutorial It is also helpful if you read the introduction to the chapter describing the Solid module in the GMS Reference Manual This will give you basic understanding of the approach used to construct solid models 3 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 3 2 Required Modules Interfaces This tutorial can be completed in either demo mode or normal model If you are already in demo mode you may continue with the tutorial If you are in normal mode you will need to ensure that the necessary components have 3 2 3 3 3 4 GMS Tutorials been licensed This tutorial utilizes the following components of the GMS interface e The TIN module He e The Borehole module p e The Solid module H e The Map module You can confirm whether each of these compon
226. sesaeseeeeseeenaes 16 10 16 8 ASSIGNING MATERIAL PROPERTIES cc cccccccecessessececececsenesececececeesesseaecececsesenssaeeecececsessaseeeeeseeeneas 16 11 16 9 ASSIGNING BOUNDARY CONDITIONS ccccccccceessssececececeeseseeececececseeaecececeesesssaeeeecceceesnaaeeeeeeeeeensas 16 12 16 9 1 aoa aaa saben cease 16 12 16 10 SAVING THE SIMULATION cccccccccccecsssssccecececsessaeeecececsesseaececececsensaaececececsesaueaecececeesennaeeeeeceesenees 16 13 16 11 RUNNING SEEP 2D 2 aaeivca rege Rates eeE 16 14 16 12 VIEWING THES OLUTION S 16 14 16 13 CONCLUSION vnc ath Bio gee Selene See sa Ge ceed 16 14 17 SEEP2ZD U NCONEINED iiss scsicenaceatensasscescsvsaesanesseasesessessannsxstoasnastancoesseceeecdsonsseassdeaneessesacessessevesesecaes 17 1 17 1 DESCRIPTION OF PROBIEM 6 022505 03 17 1 17 2 GETTING STARTED 17 2 17 3 REQUIRED MODULES INTERFACES scccccccecsesessscecececeesesesesececeeseseaeseeeceeseaaeeeccceeeesaaeeeeeeeeeersaaeees 17 2 FA CREATING THE MESH tude ASG abe sen 17 2 17 4 1 Defining a Coordinate System 17 3 17 4 2 Ah Ne SE ERS SSE es A tes lesbos 17 4 17 4 3 Creating the Cor
227. should be completed before attempting the Three Dimensional Geostatistics tutorial 4 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 4 2 Required Modules Interfaces This tutorial can be completed in either demo mode or normal model If you are already in demo mode you may continue with the tutorial If you are in normal mode you will need to ensure that the necessary components have 4 2 4 3 GMS Tutorials been licensed This tutorial utilizes the following components of the GMS interface 2D Scatter Point module e The 2D Grid module You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If each of these items is enabled you can proceed to complete the tutorial in normal mode If not you will need to switch to demo mode before continuing To switch to demo mode 1 Select the Demo Mode command from the File menu 2 Select OK at the prompts Importing a Scatter Point Set Interpolation in GMS is performed using scatter points A set of 2D scatter points is defined by a set of xy coordinates A group of scatter points is called a scatter point set Each scatter point set has a list of scalar data sets Each data set represents a set of values that c
228. snedussbeveneuevendenbereeasenenys 15 2 15 3 REQUIRED MODULES INTER FACES E S EEE E EORR EIS r ETE IE RES 15 2 15 4 BUILDING THE CONCEPTUAL MODEL 15 3 15 4 1 Importing the Background 1 15 3 15 4 2 Initializing the FEMWATER 15 3 15 4 3 Defining the Units Ae ei 15 4 15 4 4 Creating the Boundary 15 4 15 4 5 Redistributing the Arc Vertis senner natns apop rae a aiie IEE 15 4 15 4 6 Defining the Boundary 15 5 15 4 7 B ilding the ay e eaS A EEE EE P aE ORAETES REEE 15 5 15 4 8 ASSIQNING the Recharge kisirani E aa EE EEE ES EENEN 15 6 15 4 9 Creating the Wells ani as SAW a a A e as ee OA 15 6 15 3 BULDNGTHE 3D MESH EOE eSa ae 15 7 15 5 1 Defining the Materials pacien E EE E NEEE E RN 15 8 15 5 2 Building the 2D Projection 15 8 15 5 3 Building the TINS cae 15 8 15 5 4 Importing and Interpolating the Terrain 15 9 15 5 5 Importing and Interpolating the Layer Elevation 15 10 15 5 6 Building the 3D Mesh sea iaa e
229. ssscecececsensssecesececsensnaeceseescseneasaeseeeceeserseaeees 13 5 13 6 1 Creating a New Coverage rrinin EE SEE E ER Aa 13 5 13 6 2 Creating the Boundary APCS 13 5 13 6 3 Building the 13 6 13 6 4 Marking the Specified Head eia espeia oe eer p eT at 13 7 13 7 CREATING THE LOCAL MODFLOW MODEL cccccccsessssecececeesessscececececsesseaeceeeceesenssaeeeeeeessenseaeees 13 7 13 7 1 CGre ting the Grid irurogei eo a E Lagasse E E capes dh AS EEEE 13 7 137 2 Activating the i aP E E EEIEIEE 13 8 13 7 3 Mapping the Attribut S suave 13 8 13 8 INTERPOLATING THE LAYER 13 9 13 9 SAVING AND RUNNING THE LOCAL MODEL c cccccccscsessscesececeesssnececececeeneaesecececeesenssaesececeenenseaeees 13 9 13 10 VIEWING THE RESULTS tev av ieee ea ede DA aL A es 13 9 3 14 SoN E BG CON Gen ner ee 13 10 14 MODEL CALIBRATION osiccsccvcsssssssssdesesonssssnnsssecscsanschinessacssevsadectessesocseacssessesenscoseassonssesesectesetesencestes 14 1 14 1 DESCRIPTION OF PROBLEM koe aeia 14 1 27 GETTING STARTED A EO E 14 3 143 REQUIRED MODULES INTERFACES csccccccccsessssececececeeseseceeececsensaaececececsenesaeseseeseseseaea
230. stimate will be computed These steps will be repeated until the error is reasonably small Model Calibration 14 3 Recharge Zones Hydraulic Conductivity Zones Figure 14 2 Recharge and Hydraulic Conductivity Zones 14 2 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 14 3 Required Modules Interfaces This tutorial utilizes the following components of the GMS interface e The 3D Grid module H e The Map module e The MODFLOW interface You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If you have licensed and enabled each of the listed items on your version of GMS you can proceed to complete the tutorial in normal mode If not you will need to obtain an updated password or hardware lock before continuing The tutorial cannot be completed in demo mode because the ability to save files is required 144 GMS Tutorials 14 4 Reading in the Model First we will read in the model 1 Select the Open command from the File menu 2 Locate and open the tutorial calib directory 3 Select the file entitled bigval gpr 4 Select the Open button You should see both a grid and a conceptual model appear The conceptual model consists of three coverages The currentl
231. t step in creating the grid is to define the location and orientation of the grid using the Grid Frame The Grid Frame represents the outline of the grid It can be positioned on top of our site map graphically 1 2 Select the Grid Frame command in the Feature Objects menu Select the New Frame button Move the boundaries of the Grid Frame by dragging the handles that appear on the corners and the midsides of the Grid Frame with the mouse Position the boundaries so that they just surround the boundaries of the conceptual model You may need to move the Grid Frame dialog once or twice as you position the Grid Frame Note In some cases the best fit of the grid to the model is achieved when the grid is rotated The Grid Frame can be rotated by selecting and dragging the rotation handle the dot just to the right of the lower right corner of the Grid Frame The Grid Frame can also be positioned and rotated using the buttons and edit fields in the Grid Frame dialog If the handles of the grid frame are not visible you may wish to select the Plan View macro or adjust the values in the edit fields until they become visible For the Z coordinate change the Origin to 550 and the Dimension to 200 This provides a set of initial values for the MODFLOW layer elevation arrays Later we will interpolate the layer elevations Select the OK button to exit the Grid Frame dialog 7 18 GMS Tutorials 7 10 Creating the Grid Now that the co
232. tant interval option Enter a value of 300 0 for the Time interval Select the OK button You should see some images appear on the screen These are the frames of the film loop which are being generated Once they are all generated you can play them back at a high speed When the hourglass cursor disappears 1 Select the Play gt button to begin the animation 10 10 GMS Tutorials 2 After viewing the animation select the Stop button to stop the animation 3 Select the Step gt button to move the animation one frame at a time 4 You may wish to experiment with some of the other playback controls When you are finished select the Done button to exit the Film Loop dialog 10 17 Modeling Sorption and Decay 10 17 1 The solution we have just computed can be thought of as a worst case scenario since we have neglected sorption and decay Sorption will retard the movement of the plume and decay due to biodegradation will reduce the concentration For the second part of the tutorial we will modify the model so that sorption and decay are simulated We will then compare this solution with the first solution Turning on the Chemical Reactions Package Sorption and decay are simulated in the Chemical Reactions Package We need to turn this package on before it can be used 1 Select the Basic Transport Package command in the MT3D menu 2 Select the Packages command 3 Turn on Chemical reaction package option
233. tarting Concentration dialog 5 Repeat this process to enter the following starting concentrations S04 9 0 mg L SEAM3D 11 7 25 0 01 mg L This concludes the input for the BTN pacakge Select the Close button to exit the Basic Transport Package dialog 11 7 Advection Package Typically the next step at this point would be to enter the data for the Advection package However the default solution scheme Third Order TVD ULTIMATE is adequate for this problem and no changes need to be made 11 8 Dispersion Package Next we will enter the data for the Dispersion package The aquifer has a longitudinal dispersivity of 10 0 ft and a transverse horizontal dispersivity of 0 5 ft The vertical dispersivity is assumed equal to the longitudinal dispersivity 1 Select the Dispersion Package command in the MT3D menu 2 Select the Longitudinal Dispersivity button 3 Select the Constant gt Grid button 4 Enter a value of 10 0 and select OK 5 Select the OK button to exit the Longitudinal Dispersivity dialog 6 Enter a value of 0 05 for the Ratio of the trans dispersivity to long dispersivity value 7 Select the Close button to exit the Dispersion Package dialog 11 9 Source Sink Mixing Package The next step is to enter the data for the Source Sink Mixing package This package is used to establish the concentration of water entering the system For our problem we have water entering the system on the left sid
234. the Assign to specified layer option and select layer 2 Select the OK button MT3DMS Conceptual Model Approach 10 13 10 21 3 Creating a Time Series Plot Next we will create a time series plot 1 sure the point you just created is still selected 2 Select the Obs Plot Options command in the Display menu 3 Select the New button 4 Inthe Plot type pull down list select the Time series option 5 Select the OK button Finally to display the plot we must open the Plot Window 1 Select the Show Plot Window command in the Display menu wk 2 Select the Frame macro A EF 10 21 4 Plotting Multiple Curves By default only the active data set is used to generate the time series plot In many cases it is useful to plot the results from two simulations at once To plot a curve for both solutions 1 Select the Obs Plot Options command in the Display menu 2 Select the Options button 3 Select the Use selected data set option 4 Highlight the data set entitled leachate the one turned off 5 Select the Display toggle 6 Select the OK button to exit the Time Series Plot Options dialog 7 Select the OK button to exit the Observation Plot Options dialog 10 21 5 Moving the Observation Point Once an observation point is created it can be moved to a new location on the grid and the plot is automatically regenerated 1 Select the Select Points Nodes tool 10 14 GMS Tutorials 2 Drag the poi
235. the File menu 2 Change the file filter to sp2 3 Select and open the file named elevs sp2 FEMWATER Flow Model 15 11 Once again before interpolating to the TIN we need to make sure the desired TIN is the active TIN 1 2 Switch to the TIN module oo In the TIN combo box at the upper left corner of the screen select the TIN named bottom upper aquifer Before interpolating we will switch back to the default interpolation method 5 Switch to the 2D Scatter Point module E Select the Interp Options command in the Interpolation menu Select the Options button next to the Inverse distance weighted item In the Nodal function section select the Gradient plane option Select the OK button and then the Close button to exit both dialogs This scatter point set has two data sets one set of elevations for the bottom of the upper aquifer and one set for the bottom of the lower aquifer We will first interpolate the elevations for the bottom of the upper aquifer Select the bot of layer 1 data set in the Data Set combo box at the top of the screen To interpolate from the scatter points to the TIN 1 2 Select the to Active TIN command in the Interpolation menu Select the OK button Finally we will interpolate the elevations for the bottom TIN Switch to the TIN module oo In the TIN combo box at the upper left corner of the screen select the TIN named bottom lower aquifer Switch to the 2D Sc
236. the file named terrian sp2 You should see a set of points appear Before interpolating to the TIN we need to make sure the top TIN is the active TIN 15 10 GMS Tutorials 1 Switch to the TIN module ee 2 Inthe TIN combo box at the upper left corner of the screen select the TIN named terrain Before interpolating we will make some adjustments to the interpolation options based on our experience with these scatter point data 1 Switch to the 2D Scatter Point module 2 Select the Interp Options command in the Interpolation menu 3 Select the Options button next to the Inverse distance weighted item 4 Inthe Nodal function section select the Constant option 5 Select the OK button and then the Close button to exit both dialogs To interpolate from the scatter points to the TIN 1 Select the to Active TIN command in the Interpolation menu 2 Turn on the Map elevations option 3 Select the OK button To view the interpolated elevations 1 Select the Oblique View macro 2 Select the Z Magnification command in the View menu 3 Enter a magnification factor of 4 0 4 Select the OK button 15 5 5 Importing and Interpolating the Layer Elevation Data Next we will import and interpolate the elevations defining the bottom of the upper and lower aquifers These elevations were obtained from a set of exploratory boreholes and were saved to a tabular scatter point file 1 Select the Import command from
237. the landfill liner system Switching Coverages 7 7 2 Before creating the recharge zones we need to make the Recharge coverage the active coverage In the Coverage combo box at the top left corner of the window select the Recharge coverage Creating the Landfill Boundary Next we will create the arc delineating the boundary of the landfill To do this we will first create a closed loop in the form of a rectangle at the approximate location of the landfill We will then edit the nodes and vertices so that the arc coincides precisely with the boundary of the landfill 1 Select the Create Arc tool 2 While watching the cursor coordinates in the bottom left corner of the Edit Window begin at the lower left corner of the landfill and create a closed rectangular loop by clicking on the following four points representing corners of the landfill Once you have clicked on the four points double click on the first point to end the loop Don t worry about getting the exact coordinates at this point Simply create the points in the vicinity of the coordinates 7 7 3 7 7 4 MODFLOW Conceptual Model Approach 7 15 x y 8810 0 3960 0 9640 0 3960 0 9640 0 4760 0 8810 0 4760 0 Now that the arc is created in the approximate location we will edit the coordinates of the vertices and nodes to define the precise coordinates 1 Select the Select Points Nodes tool 9 2 Select the Node in the lower left corner o
238. ting a shaded image Select the Shade macro Og To revert to wireframe view Select the Refresh macro ef Stratigraphy Modeling With Solids 3 13 3 13 Constructing the Blue Seam Next we will construct the lower blue seam This solid can be constructed simply by filling between the two TINs defining the top and the bottom of the seam When this method is used it is important that the top TIN is first selected followed by the bottom TIN 1 Select the TIN entitled topblue2 NOTE In some cases the TIN icons are grouped together and it is difficult to be sure your are selecting the proper TIN In such cases it is often helpful to select the Select from List command in the Edit menu This command allows you to select a TIN by choosing the name of the TIN from the list of currently defined TINs While holding the Shift key select the TIN entitled botblue2 Select the Fill Between TINs gt Solid command from the Build TIN menu Enter blue2 for the name of the solid Select the OK button 3 14 Subtracting the Blue Seam At this point the blue seam and the red solid occupy the same space To create an accurate stratigraphy model we must make a hole in the red solid at the location of the blue seam This can be accomplished by subtracting the blue seam from the red solid using a set operation 1 Switch to the Solid module tol Choose the Select Solids tool Ga Select the solid entitled red While
239. to MODFLOW Layers command in the Interpolation menu Select the OK button Note how the bottom of the first layer extends above the ground surface on the right side of the model Correcting the Layer Values To correct the layer errors 1 2 3 4 Switch to the 3D Grid module g Select the Check Simulation command in the MODFLOW menu Select the Run Check command Select the Fix Layer Errors button In this case we wish to fix the errors for layer one by moving the bottom of layer one down to were it is just below the ground surface This can be accomplished using the Preserve top option 1 2 3 4 Select the Preserve top option Make sure Layer is selected in the list Select the Fix Selected Layer button Exit both dialogs Notice how the outcropping is now properly modeled When finished viewing the cross section K Select the View K Axis macro button i 12 10 GMS Tutorials 12 10 Case 4 Bedrock Truncation The final case we will examine is shown in Figure 12 5 The site has three layers but the layers are truncated by the bedrock on the sides of the model We will model this situation by inactivating the cells on the perimeter of the model that are below the bedrock elevation We will also adjust the layer bottom elevations as necessary to accurately model the bedrock a b Figure 12 5 Typical a East West and b North South Cross Se
240. to change the current layer For our problem we need all of the values in the array to be greater than zero except for the left column of the top two layers which should be less than zero By default the values in the array should already be greater than zero Therefore all we need to do is change the values for the constant head cells This can be accomplished by entering a value of 1 for each of the thirty constant head cells However there is another way to edit the IBOUND array that is much simpler for this case This method will be described later in the tutorial For now we will leave all of the cells active Select the OK button to exit the BOUND dialog Starting Heads The next step is to set up the Starting Heads array Select the Starting Heads button The Starting Heads array is used to establish an initial head value when performing a transient simulation Since we are computing a steady state simulation the initial head for each cell shouldnt make a difference in the final solution However the closer the starting head values are to the final head values the more quickly MODFLOW will converge to a solution Furthermore for certain types of layers if the starting head values are too low MODFLOW may interpret the cells as being dry For the problem we are solving an initial value of zero everywhere should suffice The Starting Heads array is also used to establish the head values associated with constant head cells For
241. ton To return to the top layer Select the Increment button twice 6 14 2 Color Fill Contours You can also display the contours using a color fill option 1 Select the Contour Options command in the Data menu 2 In the lower left section of the dialog select the Color fill between contours option 6 16 GMS Tutorials 3 Select the OK button 6 14 3 Color Legend Next we will display a color legend 1 Select the Color Ramp Options command in the Data menu 2 In the upper right corner of the dialog select the Show color legend option 3 Select the OK button 6 15 Conclusion This concludes the MODFLOW Basic tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt 7 MODFLOW Conceptual Model Approach Two approaches can be used to construct a MODFLOW simulation in GMS the grid approach or the conceptual model approach The grid approach involves working directly with the 3D grid and applying sources sinks and other model parameters on a cell by cell basis The steps involved in the grid approach are described in the previous tutorial entitled MODFLOW Grid Approach The conceptual model approach involves using the GIS tools in the Map module to develop a conceptual model of the site being modeled The location of sources sinks layer parameters such as hydraulic conductivity model boundaries and all other data necess
242. tour Options command in the Data menu 2 Turn on the Color fill between contours option 3 Select the OK button 9 5 10 Setting Up a Film Loop Finally we will observe how the solution changes over the one year simulation by generating a film loop animation To set up the film loop 1 Select the Film Loop command in the Data menu 2 Select the Setup button 3 Turn on the Display clock option 4 Select the Use constant interval option and change the Time interval to 36 5 This will result in 11 frames 5 Select the OK button 9 14 GMS Tutorials You should see some images appear on the screen These are the frames of the film loop which are being generated When the filmloop is finished generating 1 Select the Run gt button to begin the animation 2 After viewing the animation select the Stop button to stop the animation 3 Select the Step gt button to move the animation one frame at a time 4 You may wish to experiment with some of the other playback controls When you are finished select the Done button to exit the Film Loop dialog 9 6 Conclusion This concludes the MT3DMS Grid Approach tutorial If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt 10 MT3DMS Conceptual Model Approach MT3DMS simulations can be constructed using either the grid approach where data are entered on a cell by cell basis or using
243. tton Select the Shade macro Og 15 22 GMS Tutorials After a short wait this may take up to several minutes depending on the machine speed and the quality of the graphics card the shaded image should appear To view the image from the other side 1 Select the Rotate tool 2 Click on the screen and drag horizontally to the left side of the screen Repeat as necessary until the other side of the model is visible 3 Select the Shade macro 59 Finally we will try the smooth shade option 1 Select the Shading Options command from the Display menu 2 Select the Smooth features option 3 Select the OK button 4 Select the Shade macro Og 15 13 Conclusion This concludes the FEMWATER Flow Model tutorial If you wish to exit GMS at this time 3 Select the Exit command from the File menu 4 Select No at the prompt 16 SEEP2D Confined 16 1 SEEP2D is a 2D finite element steady state flow model It is typically used for profile models i e cross section models representing a vertical slice through a flow system which is symmetric in the third dimension Examples include earth dams levees sheet piles etc SEEP2D can be used for both confined and unconfined problems Accordingly the SEEP2D tutorials are divided into two parts The tutorial in this chapter describes how to set up and solve a confined seepage problem for SEEP2D using GMS The steps required for simulating the unconfi
244. tton to exit the 2D Interpolation Options dialog To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter idw_const for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og The IDW scheme is a simple moving weighted averages scheme To interpolate a value at a point a weighted average of the nearby scatter points is used The weights are an inverse function of distance The closer a scatter point is to the interpolation point the greater the weight given to the scatter point 4 13 IDW Interpolation With Gradient Planes One of the problems with simple ZDW interpolation is that the interpolated data set always tends toward the mean of the data set in the voids between scatter points As a result local minima or maxima in the voids in the scatter point set are not properly inferred To overcome this problem a nodal function can be computed at each scatter point A nodal function is a plane or quadratic function that is forced to pass through the scatter point and approximate the nearby scatter points in a least squares sense When the 4 8 GMS Tutorials 4 14 interpolation is performed rather than computing an average of the data set values at the scatter point locations an average is computed of the nodal functions of the nearby scatter point evaluated at the interpolation point This approach allows local trends to be inferred and often results in a more
245. ulation 1 Select the Read Solution command from the MT3D menu 2 Select the OK button 3 Inthe TS combo box at the top of the window select the last time step Notice that at the end of the simulation the plume is smaller and less advanced than in the first simulation 10 12 GMS Tutorials 10 21 Generating a Time History Plot A useful way to compare two transient solutions is to create an observation point and generate a time history plot 10 21 1 Creating an Observation Coverage The first step in generating a time history plot is to create an observation coverage in the Map module 8 9 Switch to the Map module Select the Coverages command in the Feature Objects menu Select the New button Enter Obs Pts for the name of the coverage Change the type of the coverage to Observation Click on the Options button Select the New button Change the name to concentration Select the OK button to exit the Observation Coverage Options dialog 10 Select the OK button to exit the Coverages dialog 10 21 2 Creating an Observation Point Next we will create an observation point Select the Create Point tool While monitoring the cursor coordinates in the Edit Window move the cursor to where the coordinates are approximately equal to 9365 0 3650 0 and click once to create an observation point With the point still selected select the Attributes command from the Feature Objects menu Select
246. ural neighbor is similar to ZDW interpolation in that it is a moving weighted average approach However the technique used to compute the weights in natural neighbor interpolation is based on topological relationships rather than distance alone This approach tends to provide good results even when the scatter points are clustered 1 Select the Interp Options command from the Interpolation menu 2 Select the Natural neighbor option 3 Select the Options button to the right of the Natural neighbor option As with ZDW interpolation we can use higher order nodal functions if desired We will use the quadratic option 1 Select the Quadratic option 2 In the Bounding pseudo points section turn OFF the Extrapolate beyond convex hull option Natural neighbor interpolation triangulates the scatter points as part of the interpolation process The boundary of the resulting TIN corresponds to the convex hull of the scatter points Computing points outside this hull is considered to be extrapolation If the values are not extrapolated a zero value is assigned to the grid nodes outside the convex hull Thus turning off the Extrapolate beyond convex hull option is a simple way to ensure that the concentrations on the perimeter of the map are zero 3 Select the OK button to exit the Natural Neighbor Options dialog 4 Select the Close button to exit the 2D Interpolation Options dialog To interpolate to the grid 1 Select the to 2D Grid co
247. ution is to generate an iso surface at a pressure head of zero This creates a surface matching the computed water table Further if we cap the iso surface on the side greater than zero we will get a color shaded image of the pressure variation in the saturated zone 1 Select the Display Options command in the Display menu FEMWATER Flow Model 15 21 Turn off the Elements option Turn on the so surfaces option Select the Options button next to the item For the first iso value enter a value of 0 0 Turn on the Cap toggle just below the first iso value Select the OK button to exit both dialogs Select the Shade macro Og 15 12 3 Draping the TIFF Image on the Ground Surface Finally we will drape the TIFF image on the terrain surface to illustrate the spatial relationship between the computed water table surface and the ground surface To do this we will first unhide the top TIN Switch to the TIN module Select the Select TINs tool oe Select the top TIN iy Select the Show macro In the TIN combo box at the upper left of the GMS screen select the terrain TIN this makes the TIN active Next we will set the option to map the TIFF image to the TIN when shaded 1 2 Switch to the Map module Select the Display Options command in the Images menu Turn on the Texture map to surface when shaded option In the combo box select the Map to active TIN option Select the OK bu
248. utorial you should have completed the Two Dimensional Geostatistics tutorials 5 1 Getting Started If you have not yet done so launch GMS If you have already been using GMS you may wish to select the New command from the File menu to ensure the program settings are restored to the default state 5 2 Required Modules Interfaces This tutorial can be completed in either demo mode or normal mode If you are already in demo mode you may continue with the tutorial If you are in normal mode you will need to ensure that the necessary components have been licensed This tutorial utilizes the following components of the GMS interface e 3D Scatter Point module 216 5 2 5 3 GMS Tutorials e The 3D Grid module You can confirm whether each of these components has been enabled on your copy of GMS by selecting the Register command from the File menu If each of these items is enabled you can proceed to complete the tutorial in normal mode If not you will need to switch to demo mode before continuing To switch to demo mode 1 Select the Demo Mode command from the File menu 2 Select OK at the prompts Importing a Scatter Point Set To begin the tutorial we will import a 3D scatter point set A 3D scatter point set is similar to a 2D scatter point set except that each point has a z coordinate in addition to xy coordinates As with the 2D scatter point set one or more scalar data sets can be associated with each scatter
249. utorials J Select OK to confirm the deletion of the current 3D grid Select OK again to confirm deletion of the MODFLOW data In the Create Grid dialog enter 60 for the number of cells in the x direction 50 for the number of cells in the y direction and 2 for the number of cells in the z direction Select OK to create the grid You should see a grid appear You can zoom in to examine the grid 1 2 Select the Zoom tool Drag a box around the grid 13 7 2 Activating the Cells Next we will inactivate the exterior cells Select the Activate Cells in Coverage command from the Feature Objects menu If the arcs match the grid boundary closely you may not see any cells inactivated If however the grid extends significantly beyond the arcs some cells will be inactivated 13 7 3 Mapping the Attributes Next we will convert the MODFLOW data to the grid 1 2 5 6 Switch to the 3D Grid module Select the New Simulation command from MODFLOW menu 4 Switch back to the Map module Select the Map gt MODFLOW command from the Feature Object menu Select OK at the prompt Once again you may wish to zoom in on the grid Note At this point our local scale model does not include the wells involved in the pump and treat system These could be added at a later time Regional To Local Model Conversion 13 9 13 8 Interpolating the Layer Data The final step in the conversion
250. utside the model to unselect the polygon 10 8 Converting the Conceptual Model At this point we are ready to assign the aquifer parameters and the recharge concentration to the cells using the conceptual model 1 Select the Map gt MT3DMS command in the Feature Objects menu 2 Make sure the All applicable coverages option is selected and select OK at the prompt 10 9 Layer Thicknesses To define the aquifer geometry MT3DMS requires an HTOP array defining the top elevations of the uppermost aquifer A thickness array must then be entered for each layer Since we used the true layer approach to build the MODFLOW model the layer geometry is automatically generated and no further input is necessary 10 10 The Advection Package Before running MODFLOW there are a few more options to enter First we need to select a solver for the Advection package MT3DMS Conceptual Model Approach 10 7 1 Switch to the 3D Grid module 2 Select the Advection Package command from the MT3D menu 3 For the solution scheme select the Method of Characteristics MOC option 4 Select the OK button 10 11 The Dispersion Package Next we will enter the data for the Dispersion package Select the Dispersion Package command from the MT3D menu The longitudinal dispersivity values were automatically assigned from the conceptual model All we need to do is specify the remaining three parameters 1 Enter a value of 0 2 for the Ratio of
251. utton to exit the 2D Interpolation Options dialog To interpolate to the grid 1 2 4 15 Truncation Select the to 2D Grid command from the Interpolation menu Enter idw_quad for the name of the new data set Select the OK button Select the Shade macro Og Notice that the minimum value listed in the color legend is 80 0 Of course this is impossible since there is no such thing as a negative concentration By inferring trends the nodal functions can sometimes project the plume values beyond zero and into the negative range This type of error can be easily fixed using truncation 1 2 Select the Options command from the Interpolation menu Turn on the Truncate values option Select the Truncate to specified range option Enter 0 0 for the min value and enter 150 0 for the max value We dont want the concentrations to go below zero but we will allow the interpolation scheme to infer a maximum concentration greater that the maximum measured value Select the OK button To interpolate to the grid 1 Select the to 2D Grid command from the Interpolation menu 2 Enter idw_quad_trunc for the name of the new data set 3 Select the OK button 4 Select the Shade macro Og Notice that the concentrations are now mostly zero around the perimeter of the map 4 10 GMS Tutorials 4 16 Natural Neighbor Interpolation Next we will test the natural neighbor interpolation Nat
252. utton to exit the Scalar Data Set Info dialog 2 Select the Done button to exit the Data Calculator dialog The contour plot now displayed represents the data set we just computed Any new data set computed using the Data Calculator is automatically designated the active data set 4 20 Deleting All Data To delete all of the data we have generated in this tutorial from memory 1 Select the New command from the File menu 2 Select No to confirm the deletion 4 21 Conclusion This concludes the Two Dimensional Geostatistics tutorial If you were originally running in normal mode and switched to demo mode to complete this tutorial you can switch back to normal mode as follows 1 Select the Normal Mode command from the File menu 2 Select the OK button at the prompt If you wish to exit GMS at this time 1 Select the Exit command from the File menu 2 Select No at the prompt CHAPTER 5 3D Geostatistics Three dimensional geostatistics interpolation are performed in GMS using the 3D Scatter Point module The module is used to interpolate from sets of 3D scatter points to 3D meshes and 3D grids Several interpolation schemes are supported including kriging Interpolation is useful for defining initial conditions for 3D ground water models or for 3D site characterization The tools for manipulating 3D scatter point sets and the interpolation schemes supported in GMS are described in this tutorial Before attempting this t
253. vations zero as the 2D mesh We will then import a set of scatter points and interpolate the proper elevations to the TINs To create the top TIN 1 Switch to the 2D Mesh module H 2 Select the Mesh gt TIN command from the Build Mesh menu 3 Enter terrain for the name of the TIN 15 5 4 3 6 FEMWATER Flow Model 15 9 From the list of materials select Upper Aquifer this defines the material below the TIN Select OK Select No at the prompt We do not want to delete the 2D mesh To create the second TIN 1 Select the Mesh gt TIN command from the Build Mesh menu 2 Enter bottom upper aquifer for the name of the TIN 3 From the list of materials select Lower Aquifer 4 Select OK 5 Select No at the prompt To create the third TIN 1 Select the Mesh gt TIN command from the Build Mesh menu 2 Enter bottom lower aquifer for the name of the TIN 3 From the list of materials select Lower Aquifer this value is ignored for the bottom TIN 4 Select OK 5 Select No at the prompt Importing and Interpolating the Terrain Data Next we will import the scatter points defining the terrain elevations and interpolate the elevations to the top TIN The terrain points were created by digitizing elevations from the contour map The points were saved in a tabular scatter point file 1 Select the Import command from the File menu 2 Change the file filter to sp2 3 Select and open
254. verages and the Grid Frame are created we are now ready to create the grid 1 Select the Map gt 3D Grid command in the Feature Objects menu Notice that the grid is dimensioned using the data from the Grid Frame If a Grid Frame does not exist the grid is defaulted to surround the model with approximately 5 overlap on the sides Also note that the number of cells in the x and y dimensions cannot be altered This is because the number of rows and columns and the locations of the cell boundaries will be controlled by the refine point data entered at the wells 2 Enter a value of 2 for the number of cells in the z direction 3 Select the OK button 7 11 Defining the Active Inactive Zones Now that the grid is created the next step is to define the active and inactive zones of the model This is accomplished automatically using the information in the local sources sinks coverage Select the Activate Cells in Coverage s command from the Feature Objects menu Each of the cells in the interior of any polygon in the local sources sinks coverage is designated as active and each cell which is outside of all of the polygons is designated as inactive Notice that the cells on the boundary are activated such that the no flow boundary at the top of the model approximately coincides with the outer cell edges of the cells on the perimeter while the specified head boundaries approximately coincide with the cell centers of the cells on the peri
255. was generated by scanning a section of a USGS quadrangle map on a desktop scanner The image has previously been imported to GMS and registered to real world coordinates The registered image was saved to a GMS project file To read the image 1 Select the Open command from the File menu 2 Locate and open the directory entitled tutorialfemwater 3 Select the file entitled start gpr and select the Open button Initializing the FEMWATER Coverage Before creating the feature objects we first need to initialize a FEMWATER coverage H 1 Switch to the Map module 2 Select the Coverages command in the Feature Objects menu 3 Change the name of the default coverage to femwater 4 Change the Coverage type to FEMWATER 15 4 GMS Tutorials 15 4 3 Defining the Units 15 4 4 Before exiting the Coverages dialog we will also define the units GMS uses the units we select to plot helpful labels next to input edit fields 1 Select the Units button 2 Check to ensure that the default Length unit is feet and the default Time unit is days 3 Change the Mass unit to slug The remaining units are for a transport simulation and can be ignored 4 Select the OK button to exit the Units dialog 5 Select the OK button to exit the Coverages dialog Creating the Boundary Arcs 15 4 5 We are now ready to begin creating the arcs defining the boundary of the model Notice that the three boundaries on the left have been
256. wheads section select the End option Select the OK button Click anywhere in window other than on a drawing object to unselect the arrow This concludes the MODFLOW Conceptual Model Approach tutorial If you wish to exit GMS at this time 1 2 Select the Exit command from the File menu Select No at the prompt 8 MODPATH This tutorial describes the steps involved in setting up a MODPATH simulation in GMS MODPATH is a particle tracking code developed by the U S Geological Survey MODPATH tracks the trajectory of a set of particles from user defined starting locations using the MODFLOW solution as the flow field The particles can be tracked either forward or backward in time Particle tracking solutions have a variety of applications including the determination of zones of influence for injection and extraction wells 8 1 Description of Problem The problem we will be solving for this tutorial is an extension of the problem described in the previous tutorial entitled MODFLOW Conceptual Model Approach If you have not yet completed the previous tutorial you may wish to do so before continuing In the previous tutorial a site in East Texas was modeled We will be using the solution from this model as our flow field for the particle tracking simulation The model includes a proposed landfill For this tutorial we will be performing two particle tracking simulations to analyze the long term effects of
257. working with other functions within GMS Once you think you have fixed the problem the Run Check command can then immediately be executed again to ensure that the error has been fixed Select the Done button to exit the Model Checker 7 16 Saving the Project Now we are ready to save the project and run MODFLOW 1 Select the Save As command in the File menu 2 Enter easttex as the name of the model 3 Select the Save button Note Saving the project not only saves the MODFLOW files but is saves all data associated with the project including the feature objects and scatter points When running multiple versions of the MODFLOW simulation the Save Save As commands in the MODFLOW menu can be used to save different versions of the MODFLOW simulation without saving the entire project MODFLOW Conceptual Model Approach 7 25 7 17 Running MODFLOW We are now ready to run MODFLOW 1 Select the Run MODFLOW command from the MODFLOW menu 2 Select the OK button At this point MODFLOW is launched in a new window MODFLOW opens the file and begins the simulation As the simulation proceeds you should see some text output in the window reporting the solution progress When the solution is finished close the window and return to GMS 7 18 Viewing the Head Contours We are now ready to view the solution 1 Select the Read Solution command from the MODFLOW menu 2 Select the OK button A set of contours should appear To get better
258. xamine is shown in Figure 12 1 This is the simplest of the cases examined in this tutorial The site has three layers and all three layers extend over the entire domain of the model 12 4 GMS Tutorials 12 7 1 ee _ Figure 12 1 Typical East West Cross Section For Case 1 Importing the Scatter Point Sets The first step in defining the layer data is to create a set of points at various xy locations in the model Each point has an elevation for the top and bottom of each layer In a real problem these data would come from sources such as exploratory boreholes Once these points are created they are entered in a tabular scatter point file The scatter point file for Case 1 is shown in Figure 12 2 The first line is a list of column names and the remaining lines are the data values This file was created in Microsoft Excel and exported as a tab delimited text file The id column is optional Note that the bottom of layer 1 is assumed to coincide with the top of layer 2 Thus only four columns are required to define the entire set of elevations id x y topi bot1 bot2 bot3 1 360 1670 450 345 200 100 2 290 870 445 340 195 95 3 480 420 450 350 200 100 4 620 2120 455 245 200 100 5 990 1820 470 355 210 115 6 890 1190 465 350 205 110 7 1030 710 475 360 215 130 8 910 590 470 350 210 125 9 1520 2100 530 405 275 185 10 1410 1560 510 390 260 210 11 1520 910 530 405 275 185 12 1320 430 560 445 3
259. y active coverage contains the model boundary the specified head boundary the stream and the wells There is also a coverage of recharge zones and a coverage of hydraulic conductivity zones For the initial simulation a single value of hydraulic conductivity 8 0 ft day and a single value of recharge 2 5e 4 ft day have been assigned The polygonal zones of hydraulic conductivity and recharge will be edited as the tutorial progresses to reduce the model error The conceptual model was used to construct the MODFLOW model that is shown The contours shown are the computed head values from the initial model parameter values 14 5 Observation Data We will be using two types of observation data in the calibration process water table elevations from observation wells and observed flow rates in the stream Since the model is in a fairly arid region we will assume that most of the flow to the stream is from groundwater flux 14 6 Entering Observation Points 14 6 1 First we will enter a set of observation points representing the observed head in the ten observation wells in the region Observation points are created in an observation coverage in the Map module Creating an Observation Coverage Before entering observation points we must first create an observation coverage H 1 Switch to the Map module Model Calibration 14 5 2 Select the Coverages command from the Feature Objects menu 3 Select the New button 4 Ent
260. y updated 2 11 Locking Vertices In many cases some of the vertices defining a TIN come from actual measured data such as a borehole log and can be considered hard data In other cases vertices are added manually and represent soft data used simply to fill in gaps When editing a TIN it is useful to distinguish between these two types of vertices so that a vertex corresponding to an actual measurement is not accidentally edited This can be accomplished by locking and unlocking vertices GMS Tutorials 1 Select several vertices by dragging a box around the vertices or by clicking on individual vertices while holding down the Shift key 2 Select the Lock Unlock Vertices command from the Modify TIN menu Notice that the color of the vertices changes when they are locked Once a set of vertices is locked the coordinates of the vertices cannot be changed 1 Click once outside the TIN to unselect the vertices 2 Select one of the vertices that you just locked 3 Attempt to edit the vertex by dragging or by entering new coordinates in the Edit Window Locked vertices can be unlocked by selecting the vertices and selecting the Lock Unlock Vertices command from the Modify TIN menu 2 12 Adding Vertices As mentioned above when working with TINs it is often necessary to edit a TIN by adding supplemental vertices to the TIN to provide more resolution or detail in an area of interest Vertices can be added to a TIN in GMS sim
261. yer Select the up arrow to the right of the layer edit field at the top of the dialog Enter the following values for layer 2 Parameter Value Bottom Elevation 400 ft Horizontal Hydraulic Conductivity 3 ft d Vertical Hydraulic Conductivity 0 5 ft d Bottom Layer Switch to layer 3 and enter the following values MODFLOW Grid Approach 6 9 Parameter Value Bottom Elevation 700 ft Horizontal Hydraulic Conductivity 7 ft d Vertical Hydraulic Conductivity 1 5 ft d This completes the data entry for this dialog Select the Close button to exit the MODFLOW Block Centered Flow dialog 6 9 The Recharge Package Next we will enter the data for the Recharge package The Recharge package is used to simulate recharge to an aquifer due to rainfall and infiltration To enter the recharge data 1 2 Select the Recharge Package command from MODFLOW menu Select the Constant gt Array button Enter a value of 0 003 Select the OK button Select the OK button to exit the Recharge Package dialog 6 10 The Drain Package We will now define the row of drains in the top layer of the model To define the drains we must first select the cells where the drains are located and then select the Point Sources Sinks command 6 10 1 Selecting the Cells The drains are located in the top layer layer 1 Since this is the current layer we don need to change the view We ne
262. you are making You may have also noticed that you are not allowed to drag an interior vertex beyond the boundaries of the adjacent triangles This prevents the triangles from becoming inverted Surface Modeling With TINs 2 5 2 9 Dragging in Oblique View When dragging in plan view the vertex is constrained to move in the xy plane To change the z coordinate we must drag the vertices in oblique view or front or side view z 1 Select the Oblique View macro leg 2 Select one of the vertices and drag the vertex up and down Notice that as you drag the vertex in oblique view you are constrained to move the vertex along the z axis 2 10 Using the Edit Window In many cases dragging vertices with the mouse is not adequately precise It is often necessary to change the vertex coordinates to a specific value This type of editing can be accomplished with the input fields at the top of the GMS window Choose one of the vertices in the TIN and select it by clicking on it with the cursor Notice that as the vertex is selected the coordinates of the vertex are displayed in the fields at the top of the window The edit fields can be used to change the x y or z coordinates of the selected vertex 1 Move the cursor to the z coordinate field and add a value of 5 0 to the current z value of the vertex 2 Hit the Return or Tab key Again as the vertex coordinates change the triangle edges and contours of the surface are immediatel

Groundwater Modeling System GMS v3.0 TUTORIALS

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