MODFLOW Surfact Tutorial
Contents
1. SURFACT is capable of working with the normal default grid size of Visual MODFLOW models and with any custom grid developed for Visual MODFLOW by Waterloo Hydrogeologic MODFLOW Surfact Tutorial 2 How to Use this Tutorial This tutorial is divided into two modules and each module contains a number of sections Each section is written in an easy to use step wise format The modules are arranged as follows Module 1 Running MODFLOW 2000 and Output Visualization Module 2 Running MODFLOW SURFACT and Output Visualization Terms and Notations For the purposes of this tutorial the following terms and notations will be used Type type in the given word or value Select click the left mouse button where indicated press the Tab key N press the Enter key Click the left mouse button where indicated 9 double click the left mouse button where indicated denotes a button to click on either in a window or in the menu bars The bold faced type indicates menu or window items to click on or values to type in Getting Started To start this tutorial the Visual MODFLOW program icon to start the Visual MODFLOW program I Eer File Open from the Main Menu Browse to the location of the tutorial files From this folder select the Airport Surfact vmf file and Open The Airport Surfact model is already built and ready to run Module 1 Running the Simulation with MODFLOW 2000 Module 1 g2. This issue can be addressed by selecting the MODFLOW SURFACT Engine for Flow In contrast to the standard MODFLOW Engines MODFLOW SURFACT is able to dynamically redistribute pumping rates to the remaining active grid cells if one or more cells in the screened interval goes dry thereby more accurately simulating the real world effects of partial overpumping of a well screened over multiple layers In view of the serious difficulties encountered with the previous increased pumping rate simulation an approach is required that allows free movement of the water table in the unconfined layers without any kind of forced convergence The MODFLOW SURFACT Flow Engine is capable of modeling unsaturated moisture and couple the surface water and eroundwater flow regimes It utilizes special numerical methods and powerful solvers to avoid the solution convergence problems caused by dry cells A brief description of the MODFLOW SURFACT capabilities is provided in Appendix C of the Visual MODFLOW User s Manual Module 2 will guide you through the selection of the MODFLOW SURFACT Flow Engine and show you how a solution for a model with dry cell problems can be obtained MODFLOW SURFACT Run Options In this section you will select MODFLOW SURFACT as the Flow Numeric Engine and re run your model e Main Menu located on the bottom toolbar Setup Edit Engines from the top menu bar The following Edit Engines dialogue will appear MODFLOW SURFACT R
3. cursor onto the model region and clicking on layer 1 Then return to the Visual MODFLOW Input menu eo Main Menu and then Input from the top menu bar You will be transferred back to the Visual MODFLOW Input section where you will increase the pumping rate causing the water table to drop below the layer bottom thereby causing problems with model convergence A Wells Pumping Wells from the Top Menu bar You will be transferred to the Pump Wells input screen eo Edit Well from the left toolbar Move the cursor to the active supply well Supply Welll and left click to edit the well An Edit Well dialog box will appear In this window Change the pumping Rate m 3 day to 1200 Ce x BRBEY rt OO Cunerd well SUPPLY WELLT a en BECA EET Re Well by name C Ew Modul C Dephta C Werte Active Well name Be SUPPLY wa 1415 5 SUPPLY WIE 1453 nm Apply vzhedule i ia all elected vedi To save your changes and run the model OK to accept these changes A Main Menu and then click Yes to save your changes OK Run rom the Top Menu bar In the Engines to Run dialog select the following options VI MODFLOW 2000 Translate amp Run After a few seconds the following message will appear indicating that the simulation has not converged MODFLOW Surfact Tutorial 8 ee mengines a X Abnormal termination See File D YvVMODNTYOther tutorials MFSurFactModelair
4. e ey Default Settings VM OD Project airport surfact Axis Ej Site maps Input Output CRER Background color Exaggeration factor 40 0 EITitle n Xd Rotate Shift Light Position Time x Ll Ei TO Dil fri v LJ i MEME p z s nd maA Options I AutoRotate v Live Update Apply Rotate model around the screen axes X up down Y left right Z rack side to side To display the depression cone ee beside Output Right click on Drawdown and select Create Isosurface The following dialogue will load F Aisosurface properties Isosurface name EISELE a tal Minimum value 0 Maximum value i 435131 sasurface value 9 50435 sasurface calor o Show borders Color from palette Colormap on cut away Ivf Remove in cut away Cancel M Show Borders M Color from Palette type 0 for the Isosurface value OK Use the Navigation Tools at the bottom of the model to position the grid so that you can clearly see the depression cone Drawdown Cone Delineation and Mass Balance Comparison 21 El Rotate Shit Light Position Time XO OQ uH X39 mM a 33 3 9L zi zm 2 ts amp utoRatate Rotate model around the screen axes s up down Y left right z rack side to side You can also display the dry cells To do so se beside Heads Dry Cells VI Vis
5. the MODFLOW SURFACT Flow Engine to see if we can obtain model convergence Main Menu located on the bottom toolbar Setup Edit Engines from the top menu bar Select MODFLOW SURFACT from HGL from the Flow Engine combo box Yes in the message OK to close the Edit Engines window To continue with the run options Run from the Main Menu options You will then be transferred to the run options screen Run from the top menu bar In the Engines to Run dialog select the following options lt WM MODFLOW SURFACT Translate amp Run When your model has successfully converged click Output menu and the Output screen will appear as shown below row 20 File Mags Graphs Tools Helo Ditpul Tome 7 0000 flap Shes paiid 1 Time stap 1 Note that the pumping induced desaturation surrounding the pumping well is represented by a smooth shaped drawdown cone which is more realistic than the one simulated by MODFLOW 2000 Note You will notice in cross section that the cone of depression drops below the bottom of the well screen This is because the general well package was used for this simulation To achieve even more realistic output select the Fractured Linear Well FLW4 packge in the MODFLOW Surfact Tutorial 18 run settings With this well package the cone of depression will not drop below the bottom of the well screen When we examine the Mass Balance of the MODFLOW SURFACT simulation b
6. the inflow and outflow of the non converged solution Mass Balance Flow E x Stress Period fi E Eirst Time Time Step fi H Last Time Time days fi r ECumulative Volumes Report n day 1 Rates for Time Step Report n IN IN Storage 0 00 rr day Storage 0 00 rrr Constant Head 2109 62 nf day Constant Head 2109 62 rrr Wells 0 00 n day Wells 0 00 rr Drains 0 00 nF day Drains 0 00 r Recharge 27 40 rr day Recharge 27 40 n ET 0 00 n day ET 0 00 nr River Leakage 256 65 nr day River Leakage 256 65 nr Stream Leakage 0 00 rv day Stream Leakage 0 00 rr General Head 0 00 rf day General Head 0 00 nr Total IN 2393 6 nf day Total IN 2393 67 nr OUT OUT Storage 0 00 rf day Storage 0 00 nr Constant Head 0 02 n day Constant Head 0 02 n Wells 3000 00 r day Wells 3000 00 rr Drains 0 00 nF day Drains 0 00 r Recharge 0 00 n day Recharge 0 00 nr ET 0 00 ne day ET 0 00 nr River Leakage 2 68 nr day River Leakage 2 68 rr Stream Leakage 0 00 nf day Stream Leakage 0 00 rr General Head 0 00 nF day General Head 0 00 rr Total OUT 3002 70 nF day Total OUT 3002 70 nr Ppscepan 220 Dsatepency 22S Print Drawdown Cone Delineation and Mass Balance Comparison 17 Simulation with MODFLOW SURFACT Now we will switch to
7. the left hand tool bar A C O Head Equipotentials contour options window will appear Contours Color Shading Lorem sd Range of Values Cut off Levels Click on the Color Shading tab Minimum 155 m Lower Level m Maximum fi 3 m Upper Level D m The contour options dialog box should appear as shown on the ri ght Transparency 33 S x M Use Color Shading um OK to accept these settings A color map of the head equipotentials for the top layer of the model will be plotted according to the default color scale selected Note that the color map is translucent in order to show the underlying model features File Maps Graphs Tools Help View Column 2 Row I Column J Layer K 1 Output Time 1 00000 day Stress period 1 Time step 1 Before you continue with this exercise turn off the color shading option to avoid the screen refresh times required to redraw the colormap Options from the left toolbar Click on the Color Shading tab Remove the checkmark VY from the checkbox O beside Use Color Shading OK A F10 Main Menu button and then Input from the top menu bar of the Main Menu You will be transferred back to the Visual MODFLOW Input section where you can modify the model input Output Visualization 5 Modifying Pumping Wells Now that we have established a baseline for the
8. 0 00 rr Drains 0 00 r Recharge 0 00 nr ET 0 00 rr River Leakage 2 79 rr Stream Leakage 0 00 rrr General Head 0 00 nr Total OUT 3002 80 nr Discrepancy 0 12 Print If time permits you may also want to experiment with the well packages available through the Engines to Run window Before running the model you can select the Advanced options and select the User Defined Settings option as shown in the following screenshot Engines to Run MODFLOW SURF MODPATH zoneBudget E FEST Di Eme fun Sere T SIE E iv NEU D efine 7 Automatic BEBE Automatic Translate amp Aun Translate Hun Cancel Standard lt lt M Auto start engines By clicking on the Drawdown Cone Delineation and Mass Balance Comparison button the Packages window will open as shown in the following 19 screenshot where you can switch between the standard well package and the FWL4 package MODFLOW SURF packages EN xj Tee ES cel Rae Ce By Solver Conjugate Gradient Solver PCG 4 T Basic Package Hun Tranzlate EIBEF4 Package Hun Translate e El well Package of Choice Standard Well Package River Package Fractured Linear well FW L4 Package tte oLandard well Package Wall Package of Choice Reset OF Cancel As described in the MODFLOW SURFACT User s Manual Chapter 3 the FW
9. 25 ht RC ISP epe ee 11 Drawdown Cone Delineation and Mass Balance Comparison 00005 14 Simulation with MODELOW 2000s 2 ganana 11k T RT eee Hee Nee cds 16 Simulation with MODFLOW SURFACT 0 ccc cee ee eee rn 18 WViASU AIAN O11 3 sace Sci Ua Sec a See a eee ea t but aus a icio e b Aled dades ST SET 20 SUMMA Vossio hes OAs Ad es He eis be Re ME eee De E Cee ake eee ease 22 Waterloo Hydrogeologic Introduction This document contains a step by step tutorial to illustrate the capabilities of the MODFLOW SURFACT Flow Engine This tutorial will guide you through the steps required to Modify and Run a flow simulation using the MODFLOW 2000 Flow Engine and inspect the output Modify and Run the same simulation using the MODFLOW SURFACT Flow Engine and compare the output to the MODFLOW 2000 simulation NOTE You must have Visual MODFLOW Standard or higher to be able to use this tutorial NOTE Some features described in this tutorial are only available in Pro or Premium versions This tutorial assumes that you are already familiar with the Visual MODFLOW interface and with the process of building a groundwater model If you are not familiar with Visual MODFLOW it is recommended that you work through the Visual MODFLOW demonstration tutorial first Benefits of MODFLOW SURFACT The key benefits of MODFLOW SURFACT for flow simulations are highlighted below e Handles complete desaturation and resatu
10. L4 package was designed to overcome several problems associated with the original WEL1 package One important feature added to the FWL4 package is the ability to adjust total well withdrawal when the water level in the well has reached the well bottom In situations where a partially penetrating well is being pumped beyond its capacity the WEL1 package incorrectly continues its calculations and allows head values to drop below the well bottom elevation In other situations the WEL1 package can cause the model to become unstable by cyclically drying and wetting the pumping cells between iterations Please NOTE that the FWL4 package will only function with 1 pumping well in the model If you choose to experiment with this package you will need to delete the second inactive pumping well before running the simulation To continue with the rest of the tutorial please see the following section describing the use of the Visual MODFLOW 3D Explorer Visualizing in 3D Now that you have examined the model in various 2D views you can visualize it in 3D To do SO F23D button on the bottom toolbar The 3D Explorer window will load as shown below MODFLOW Surfact Tutorial 20 El ymop 3D Explorer D YMODNT Other tutorials MFSurfactModel airport surfact E 2 0 xl File Edit View Options Settings Help es J i8 ag f l Exaggeration factor 40 xj Stay on top iv Airport surfact Pi e v e e
11. MEngines window Output from the top menu bar of the Main Menu MODFLOW Surfact Tutorial 6 You will be transferred to the Visual MODFLOW Output section where you will view the new simulation results This section provides instructions on displaying the de saturated conditions i e dry cells Upon entering the Output section Visual MODFLOW will automatically load the available Output files for Heads HDS and the Output screen will appear as shown below File Maps Graphs Tools Help Select Pl P uem X 2241 0 Yi 6 Z J Row I 500 po 2000 Column 7 Layer K 1 Output Time 1 00000 day Stress period 1 Time step 1 View Row from side menu bar and then move your cursor onto the model region Click on a row to show the cross section with the cone of depression around the pumping well and dry cells The display should look similar to the following figure row 30 File Maps Graphs Tools Help E D Previous Select x Y t Row I 30 Column J Layer K Output Time 1 00000 day Stress period 1 Time step 1 Modifying Pumping Wells 7 The profile shows that the water table is still within the well screen but note that the top cell of the well has dried out indicated by olive colored cells Once you have viewed the results from your model return to a plan view by clicking the View Layer button then moving your
12. Visual MODFLOW Premium with MODFLOW SURFACT A Step by Step Tutorial for the MODFLOW SURFACT Trial Version Ajrpart Mz 5 Time dawvy 0 0 Waterloo Hydrogeologic TABLE OF CONTENTS Modic vis ES M AER EUR AE E MERE EAE 2 Benefits of MODELOW SUREACT 3 ov nce Sys ee woh SEE SR ERA EE ME ES 2 MODFLOW SURFACT Interface in Visual MODFLOW 0 0 00 cc eee 2 Limitations of the MODFLOW SURFACT Trial Version 0 0 0 ee eee 2 How to Use this Tutorial 422 ud dete na A Eee BRE a eee Ewa Rs 3 Terms 3nd NOMNONS eius 1arRosy wired Bare a ca cetero ao aor S cta 9 a ued See ded A ot 3 Gemine SUA en Aneel oed ach eto e Ael e aep a sapete lorum dans patuere aa uo desi Mrd aes 3 Module 1 Running the Simulation with MODFLOW 2000 3 Riunnins the sItmuldtot us aos vire caos eet edades em aban equ ad dad ardt uie eo 3 UU Visualiza cei eos qaos qf dede Ren UT Ut o rer ered on av eens has ire oua ORE ee us a an dr dude die 4 Displaying a Color Map Or HIeadsc c au seno oe oe io rece Ec b bone xw bes maed 5 Modine Pumpin Wells 3 aoi osid eR AED a OP Race ea Rua bcd eee ered 6 R n the Simulation s over cew be Acie eee Deke eee wy eee ate Veen ond ao RUE GU aeta d 6 Output VisuabiZablofi sobretodo tede Sab ated ais dece dee debe babe tice die a ai ii 6 Module 2 Running with MODFLOW SURFACT 11 Why MODELEOW SUREACT 23 24 32430 0busknidadakabeedua hats ewdwashes 11 MODFLOW SURFACT Run Options 22322
13. ation iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iD CO J c Cn 5 co Nh residual residual residual residual residual residual residual residual residual residual residual residual residual residual residual residual JoH o B C HR o C Q5 5 DOO OO S H Cn 225E 01 587E 01 483E 01 334E 02 516E 02 830E 02 484E 02 207E 02 750E 02 O90E 02 115E 02 864E 02 639E 02 078E 02 173E 02 666E 03 X to close the VMEngines dialog Although the solution has not converged we can examine the cross sectional water table profile of the failed simulation to gain insight into the issue Output from the top menu bar of the Main Menu You will be transferred to the Visual MODFLOW Output section View Row from side menu bar to view the cross section with the the dry cells desaturated condition The display should look similar to the following figure at row 30 Tools Help File Maps Graphs mme esos E n B Y Open Close 3D Explorer You may try to increase the number of outer iterations to 500 To do this F10 Main Menu Run MODFLOW 2000 Solver Type 500 in the MXITER field OK Once you finished with the settings re run the simulation You will see that the repeating pattern of head residua
14. ber of outer iterations 50 has been reached without satisfying the head change criterion and a Stop no convergence message is displayed at the end eo La Show files icon and an Open window will appear In this window select AIRPORT SURFACT LST and click Open to view the Listing file Scroll down to examine the Cell conversions for iter entries starting approximately 1 4 through the file when MODFLOW converts a cell from wet to dry or vice versa You can see that some cells in layer 1 rows 29 32 are dry which is preventing the model convergence ENYMEngine D MODNT Other tutorials MFSurfactModel airport surfact mja x File Run Option Help Sard J IV Force switch to active engines D airport surfact MODFLOW 2000 x MODFLOW 2000 ge n PY Z D WMODNT Other tutorials MFSurfact Model AIRPORT SURFACT LST SOLUTION BY CGSTAB P CELL CONVERSIONS FOR ITER 5 DRY 29 28 DRY 29 29 DRY 30 30 DRY 31 23 DRY 32 LAYER 1 DRY 30 DRY 31 STEP 1 PERIOD 1 20 DRY 30 23 28 DRY 31 29 ROW COL DRY 30 27 DRY 32 20 Engine MODFLOW 2000 Modifying Pumping Wells iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration iteration n amp n amp n amp n Cn amp n amp n C amp n Ci C amp n Ci C n i iteration iteration iter
15. d customize hydraulic properties of the porous media and phase constants Groundwater flow Pseudo soil function Groundwater flow van Genuchten e Groundwater flow Brooke Corey e Soil Vapor flow van Genuchten e Soil Vapor flow Brooke Corey In this tutorial the Groundwater flow Pseudo soil function simulation type will be used If this option is not already selected click the pull down menu and select it from the list It simulates 3 D variably saturated flow and can easily handle unconfined saturated unsaturated moisture movement OK to close the Vadose Zone window lt a F10 Main Menu located on the bottom toolbar er Run from the Main Menu options You will be transferred to the Visual MODFLOW Run section Prior to running the model in the Run section you could customize the default run time settings for MODFLOW SURFACT including Time steps for each stress period This option is activated only when transient flow is simulated MODFLOW SURFACT includes adaptive time stepping schemes with automatic generation and control of time steps to efficiently perform transient simulations Initial Heads provide the reference elevations for the heads in steady state solution and can reduce the required run time significantly Solver selection and settings Note that PCG4 is specially designed for MODFLOW SURFACT PCG4 is a simple robust and efficient solver which requires less computer resources than the PCG2
16. ible in the Properties frame b Visible 8 Coe Clip in cut away View Semitransparent Toggles the current component on and off Checked equals on Iv Live Update Apply Feel free to experiment with other features of the 3D Explorer Summary In this tutorial we have shown that model convergence difficulties arise when attempting to simulate the hydrogeological environment using the standard MODFLOW code The steep hydraulic gradients surrounding the pumping well posed problems within the unsaturated zone of the model The pseudo soil function of MODFLOW SURFACT was chosen to account for the saturated and unsaturated processes within the model as it avoids the wet dry non linear iterations of standard MODFLOW The main benefit of MODFLOW SURFACT is that the user is able to focus on their model calibration rather than model stability The major features of MODFLOW SURFACT when coupled with Visual MODFLOW include e Extending the capability of Visual MODFLOW to handle Vadose Zone and Vapor flow simulations Greater stability and faster model convergence with complex solutions Accurate handling of pumping wells screened across multiple layers These features make MODFLOW SURFACT an excellent addition to the Visual MODFLOW modeling package MODFLOW Surfact Tutorial 22 Summary 23
17. ify the Constant Head boundary conditions assigned along the north boundary Use the overlay picklist on the left hand toolbar to switch from the Pump Wells to the Const Head overlay scroll through the list to find Const Head poly schedule kor al odeceden ccc Yes to save your changes Edit Group from the left hand toolbar A Constant Head Edit Group window will appear The brown colored cells at the top of the model and they will be highlighted in pink Change the head values by clicking in the Start Time Head column then editing the SSHEAD text that appears above the column heading Repeat for the EHEAD text Start Time Head m 18 Stop Time Head m 18 ad OK to accept these values The pink line of grid cells will turn back to a brown color indicating that the Constant Head boundary condition has been changed for these cells Drawdown Cone Delineation and Mass Balance Comparison 15 Simulation with MODFLOW 2000 You will first run MODFLOW 2000 to see the effect of the input changes e Main Menu located on the bottom toolbar eo Yes to save your changes d Setup Edit Engines from the top menu bar MODFLOW 2000 from the Flow Engine combo box eo Yes in the message OK To continue with the run options Run rom the Main Menu options You will then be transferred to the run options screen A Run from the top menu bar In the Engines to Run dialog select the f
18. l changes in the VMEngines window i e oscillation assures you that the problem can not be resolved by increasing the number of outer iterations You could try smoothing out the hydraulic conductivity gradients or redesigning the grid or using another solver or adjusting the re wetting parameters However with high pumping rates the problem of dry cells often cannot be avoided In such a situation we need to look for another solution MODFLOW Surfact Tutorial 10 Module 2 Running with MODFLOW SURFACT Why MODFLOW SURFACT Using the MODFLOW 2000 Engine a multi layer well is represented as a group of single layer wells and fails to take into account the inter connection between various layers provided by the well One of the most significant problems related to this approach is that well grid cells are essentially shut off when the water table drops below the bottom of the grid cell 1 e when the grid cell becomes dry This reduces the total pumping rate of the well as the rate 1s distributed between all the screened cells initially and may cause the water table to rebound and re activate the dry well grid cell This type of on again off again behavior for the pumping well s causes the solution to oscillate and may prevent the model from converging to a solution In the event the model does converge to a solution the model results may be misleading if one or more pumping wells have lower than expected total pumping rates
19. ollowing options lv MODFLOW 2000 Translate amp Run After a few seconds the following message will appear mengines X Abnormal termination See File D YvmODNTYOErher tutorials MFSurfact Model airport surfact LST Far details Although the solution has not converged we can examine the cross sectional water table profile of the failed simulation to gain insight into the issue OK to close the dialog box and Close the VMEngines window Output from the Top Menu bar of the Main Menu You will be transferred to the Visual MODFLOW Output section Visual MODFLOW will automatically load the available Output files for Head HDS Click View Row and move your cursor onto the model region Click to select a cross section view and the Output screen will similar to the screenshot below row 20 MODFLOW Surfact Tutorial 16 Ki L626 0 Y 1025 0 Z 74 Row E 20 CERTA fie fuss s ees tel ts Dutput Time 1 00000 day Stress period 1 Time step 1 Note that the pumping induced dry cells drawdown cone surrounding the pumping well are limited to the shape of model grid and therefore the distribution of the desaturated zone is not realistic Next we will take a look at the Mass Balance of this simulation Maps then select Zone Budget Mass Balance from the Left Menu bar When we examine the Mass Balance of the MODFLOW 2000 simulation we can see the obvious discrepancy between
20. pare the Mass Balance results from the MODFLOW 2000 and MODFLOW SURFACT runs e View Layer on the side toolbar then move your cursor onto the model region and click on Layer 1 to return to a Plan View eo Main Menu located on the bottom toolbar s Input from the Main Menu options MODFLOW Surfact Tutorial 14 Now you will move the active pumping well Supply Welll from its existing location to the center of the model grid Wells Pumping Wells from the top menu bar To move the pumping well to the center of your model Move Well Move the cursor to the top left pumping well and left click to select the well then move the cursor to the center of the model and left click to move the pumping well to the new location Edit Well from the Side Menu bar Click on the well at it s new location and an Edit Well window will appear shown below Enter the following information in the top row of the well table Supply Well1 X 975 Y 1020 To modify the Screened Intervals click in the column labelled Screen Top and enter the following values Screen Top m 14 0 Screen Bottom m 1 29 In the Pumping Schedule frame left CI H MM 9 0 F A OS x BASE Y r Oo click inside the text box under the column 77 55 labelled Rate and enter the following Cows eun information Rate m S3 day 3000 OK to accept this well information Next you will mod
21. port surfact LST For details OK to close the dialog Expand the solver iteration window so you can see the VMEngine window as shown below BA MEngine D YMODNT Other tutorials MFSurfact Model airport surfact d ni x Fie Run Option Help we B Dl nj F JV Force switch to active engines D airport surfact Dw 2000 bas MODFLOW 2000 Project airport surfact Stress period E Time step f BHA IARAA Bak Residual and Max head change vs iteration number BiCGSTAB P Matrix Solver WHS M Properties Value Factorization level Level 0 z Max outer iterations MXITER 50 Max inner iterations ITER1 25 Damping factor DAMP 0 75 Head change criterion HCLOS 0 01 Residual criterion ACLOSE 0 01 Relative residual criterion RSC 0 v 1 06 1 371 Stop scrolling Outer iter 4 Inner iter 25 Max residual 1 071E 02 Max chat Residual 0 871 Changes 3 94 Outer iter 48 Inner iter 25 Max residual 1 420E 02 Max char Outer iter 49 Inner iter 25 Max residual 2 210E 02 Max chat 0 371 Outer iter 50 Inner iter 25 Max residual 1 533E 02 Max chat Stop no convergence Last 1 0 in PLL1SD CLOSE I Error Last 1 0 in PLL1SD CLOSE I 4 b Current solver WHS 0 128 8 94 1 11 21 31 41 Iteration number Help Close Engine MODFLOW 2000 Note that the maximum num
22. ration of grid cells Capable of modeling the movement of water through the Vadose Zone Accurate delineation and tracking of water table position taking into account flow in the unsaturated zone delayed yield and vertical flow components e Automatic and correct redistribution of the total flow rate of a well screened through multiple model layers when the upper cell s are pumped dry e Accommodation of well bore storage and overpumped wells Prevents water table buildup beyond a specified recharge ponding elevation Handling of seepage face boundary conditions Adaptive time stepping schemes automatically adjust time step size to the non linearities of the system to optimize the solution stability Robust and efficient Pre conditioned Conjugate Gradient matrix solver Capability of modeling unsaturated water or air movement Enhanced Newton Raphson linearization option increases robustness for unconfined and or unsaturated flow conditions MODFLOW SURFACT Interface in Visual MODFLOW Currently Visual MODFLOW supports a graphical user interface for the Flow component of MODFLOW SURFACT Transport simulations are not supported when using the MODFLOW SURFACT Flow Engine Limitations of the MODFLOW SURFACT Trial Version The Trial version of the MODFLOW SURFACT Flow Engine is restricted to A model size of 50 rows by 50 columns by 5 layers e A maximum of 5 stress periods and 50 time steps The fully licensed version of MODFLOW
23. simulation we will modify the pumping wells to show how dry cells create model convergence problems for MODFLOW 2000 amp Wells Pumping Wells from the top menu bar Edit Well from the left toolbar Move the cursor to the Supply Well2 located in the lower right and left click to edit the well An Edit Well window will appear Supply Well2 is the second row in the well table indicated in the figure below In this row remove the checkmark v from the Active column to deactivate this pumping well Now select Supply Welll from the well table by placing your cursor in the first Vue reta as tata B S Deion 67 Model row of the well table To change the Screened Intervals Click in the column labelled Screen Top and enter the following values Screen Top m 14 0 Screen Bottom m 0 3 Change the pumping Rate m 3 day to 780 Tum poy whadu tor ul nelected cult OK to accept these changes F10 Main Menu and then click Yes to save your changes and return to the Main Menu Running the Simulation To continue with the run options Run rom the Main Menu options Run rom the Top Menu bar In the Engines to Run dialog select the following options M MODFLOW 2000 Translate amp Run Visual MODFLOW will then Translate the Visual MODFLOW data set and Run the simulation Output Visualization Once the model has converged you may Close the V
24. solver in MODFLOW Under the Recharge settings in addition to Recharge options for MODFLOW MODFLOW SURFACT allows you to simulate a Seepage Face Boundary Condition In this tutorial the Recharge is applied to the uppermost active layer option is selected Layers settings are used to set the Interblock transmissivity and Layer type The two settings are combined to make up the LAYCON value which is used by the numeric engines Note that in MODFLOW SURFACT the variably saturated flow options are implemented with Value 40 and 43 for all layers in the model grid as shown below Layer Settings x To assign multiple layers select appropriate rows by zLtrb er Shift click an row indicator bar Layer LAYCON Interblock transmissivity O Laerte b 43 40 Harmonic mean conductivit 5 3 Confined Uncontined variab 2 43 40 Harmonic mean conductivit 3X Confined Uncontined variab 7 3 43 se 40 Harmonic mean conductivit 3 Confined Uncontined variab 7 m 4 40 40 Harmonic mean conductivit O Confined constant S T OF Cancel E Rewetting settings are used to specify the conditions under which Dry Cells will become Wet again Anisotropy dialogue allows you to set the horizontal anisotropy by layer MODFLOW SURFACT Run Options 13 Using the Output Control dialogue you can customize the parameters and times that will be printed into the LST file and or sa
25. uides you through the run of a simulation using MODFLOW 2000 Run from the Main Menu Running the Simulation Run rom the Top Menu bar An Engines to Run dialog box will appear listing the available Numeric Engines as shown in the figure below Engines to Run Engne Run b MODFLOw 2000 i M DPATH ZoneBudget E MT3DMS m PEST m Cancel Advanced gt gt v Auto start engines In the Engines to Run dialog select the following options lv MODFLOW 2000 Translate amp Run Visual MODFLOW will then Translate the Visual MODFLOW data set into the standard data input files required for the selected Numeric Engines and then Run the simulations in a separate window labelled VMEngines Output Visualization Once the model has converged you may Close the VMEngines window Output from the top menu bar of the Main Menu Upon entering the Output section Visual MODFLOW will automatically load the available Output files for Head HDS for all output times Once these data files are loaded the Output screen will appear File Maps Graphs Tools Help view Row Time Next Select m mal T z Row I 600 2300 1200 1500 1800 2000 Column I F5 2 F6 2 Fe Vert F3 Over g Set equipotential contour options MODFLOW Surfact Tutorial Displaying a Color Map of Heads Options button from
26. un Options 1 Time Option Start Date 2 10 2004 Start Time 12 00 00 AM Hun Type Steady State Flow Steady State Simulation Time f day Flow Option Flow Engine usas MODFLOW 2000 fram wHI Simulation Type Groundwater flow Compatible Transport Waran Transport Engine MT3DMS Total Number of Species i Sorption No sorption simulated Humber of Mobile Species f Reactions No kinetic reactions Parameter variability N A Description DoD MT3DMS v 3 00 4 Public Domain Delete Copy Hew Edit Select MODFLOW SURGFACT from HGL from the Flow Engine combo box The following message will appear Switching to a new Flow engine may result in new Run Settings Please consult your User s Manual Far detailed descriptions of the default Engine Run Settings Do you want to proceed Yes to close the message window OK to close the Edit Engines dialogue Input from the top menu bar q S 4 Properties from the top menu bar and then Vadose Zone NOTE The Vadose Zone menu is only available when MODFLOW SURFACT is the selected Flow Engine The Vadose Zone window will open as shown below Vadose Zone d Sail Parameters Setting Simulation type Relative Permeability weight Upstream weighting Water Table Elevation m E OF Cancel MODFLOW Surfact Tutorial 12 From this window you may select different simulation types as listed below an
27. ved to the binary file List File Opt allows you to specify which information will be written to the listing file LST as well as the format of this information Run rom the top menu bar In the Engines to Run dialog select MODFLOW SURFACT M MODFLOW SURFACT Translate amp Run Close to close the VMEngines dialog once the solution has converged Output from the top menu bar of the Main Menu You will be transferred to the Visual MODFLOW Output section The display should look similar to the following figure row 30 File Maps Graphs Tools Help View Row Goto Previous Next Next to Output Time 1 00000 day Stress period 1 Time step 1 As you can see there are still dry cells at the top of the well however the model converged Drawdown Cone Delineation and Mass Balance Comparison In this section you will modify the constant head boundary conditions and move the active pumping well to the center of the model You will increase the pumping rate and then run both Numeric Engines MODFLOW SURFACT and MODFLOW 2000 The input changes will create a steep hydraulic gradient drawdown around the well and demonstrate how the pumping induced dry cells are more realistically represented with MODFLOW SURFACT than with MODFLOW 2000 i e the shape of the drawdown cone obtained by MODFLOW SURFACT will be much smoother than the shape obtained by MODFLOW 2000 Additionally you will com
28. y clicking on Maps Zone Budget from the Top Menu bar then clicking on Mass Balance from the Left Menu bar we can see that the percent discrepancy is much better indicating we have a much more accurate solution Since MODFLOW SURFACT can automatically redistribute pumping rates when well cells go dry a more accurate flow calculation can be made Mass Balance Flow E Stress Period fi H First Time Time Step fi Time days fi Last Time F Cumulative Volumes Report n day IN Storage 0 00 n day Constant Head 2741 70 rr day Wells 0 00 nP day Drains 0 00 re day Recharge 27 40 nF day ET 0 00 n dav River Leakage 237 28 nr day Stream Leakage 0 00 n day General Head 0 00 nF day Total IN 3006 40 rr day OUT Storage 0 00 nF day Constant Head 0 02 n day Wells 3000 00 nf day Drains 0 00 re day Recharge 0 00 rre day ET 0 00 n day River Leakage 2 79 n day Stream Leakage 0 00 n day General Head 0 00 rr day Total OUT 3002 80 n day L Discrepancy 0 12 Rates for Time Step Report n IN Storage 0 00 rr Constant Head 2741 70 rrr Wells 0 00 rr Drains 0 00 nr Recharge 27 40 rr ET 0 00 nr River Leakage 237 28 nr Stream Leakage 0 00 rr General Head 0 00 nF Total IN 3006 40 rr OUT Storage 0 00 rr Constant Head 0 02 n Wells 300
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