MODPATH Project Workflow

To build a MODPATH model in GMS, use the following steps:

1. Start with a completed MODFLOW Project.
Open a completed MODFLOW project created using either the grid approach or conceptual model approach.

2. Assign porosities.

Assign porosity using one of the following methods: 1. Assign porosity in the conceptual model. Using the Select Polygon tool, right-click on polygons and select the Attribute Table command. Assign porosity in the Attribute Table dialog. (Requires Porosity be selected in the Coverage Setup dialog.) Right-click on the coverage and select the Map to | MODFLOW/MODPATH menu command. 2. Assign porosity using MODPATH. Select the MODPATH | Porosity menu command. Assign porosity in the Aquifer Layer Porosity array editor. 3. Assign through grid properties. Using the Select Cell tool (for either a 3D grid or UGrid), right-click on cells and select the Properties command. Enter porosity in the MODFLOW tab of the 3D Grid Cell Properties dialog or UGrid Cell Properties dialog.

3. Define starting locations

1. Automatically create particle starting locations. Select the MODPATH | Create Particles at Wells menu command. Define particles in the Generate Particles at Wells dialog. 2. Manually create particle starting locations. Using the Select Cell tool, right-click at the starting location cell and select the Create MODPATH Particles command. Define particles in the Generate Particles at Wells dialog. Select the MODPATH | Create Particles at Wells menu command. Define particles in the Generate Particles at Wells dialog.

4. Set particle set properties.

5. Create additional particles sets.

6. Create zone codes.

7. Run MODFLOW.
Save the project. Run MODFLOW .

8. Visualize the solution.

1. Change display options. 1. Set display options. Open the Display Options dialog. Set the general display options. Set general lighting options. Set display options for each module that is being used. Set contour options. Set vector options. 2. View display. Use the Rotate , Pan , and Zoom tools. Use the View menu commands found in the Display menu. Use the Frame command to center and resize the display as needed. 3. Adjust display. Display may need to be adjusted during the remainder of the project. Use the Display Options dialog and viewing tools as needed. Use the Frame command to center and resize the display as needed. 2. Change contour options. Turn on Contours in the Display Options dialog and set contour options. The "Color Fill" option is recommended for this. Look for inconsistent points (points with values much higher/lower than their neighbors or regions where no data points exist). Verify that the region being modeled is covered by the elevation/depth data and there are no holes. 3. Create a plot. 1. Start the plot wizard. Select the Display | Plot Wizard menu command. Note that some plots require an observation coverage exist in the project. 2. Select available plot type. 1. Computed vs. Observed Data plots. 1. Computed vs. Observed Data. Select Display | Plot Wizard to start the Plot Wizard. Select the "Computed vs. Observed Data" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 2. Computed vs. Observed Data (Weighted). Select Display | Plot Wizard to start the Plot Wizard. Select the "Computed vs. Observed Data (Weighted)" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 2. Residual vs. Observed Data plots. 1. Residual vs. Observed Data. Select Display | Plot Wizard to start the Plot Wizard. Select the "Residual vs. Observed" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 2. Residual vs. Observed Data (Weighted). Select Display | Plot Wizard to start the Plot Wizard. Select the "Residual vs. Observed (Weighted)" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 3. Parameter Sensitivity plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Parameter Sensitivity" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 4. Error vs. Simulation plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Error vs. Simulation" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 5. Error vs. Time Step plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Error vs. Time Step" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 6. Error Summary plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Error Summary" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 7. Time Series plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Time Series" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 8. Active Dataset Time Series plot. Select a dataset in Project Explorer. Select cells in the project. Select Display | Plot Wizard to start the Plot Wizard. Select the "Active Dataset Time Series" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 9. S/S Flow vs. Time plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "S/S Flow vs. Time" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 10. Flow Budget vs. Time plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Flow Budget vs. Time" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 11. Gage Package Value vs. Time plot. Select Display | Plot Wizard to start the Plot Wizard. Select the "Gage Package Value vs. Time" option on the left and click Next. Specify plot options in step 2 of the Plot Wizard then click Finish. Review plot window. 4. Create an animation. Select a solution dataset and use the Display | Animate menu command. Use the Animation Wizard to specify the animation parameters. Save and view the animation file. 5. Review the zone and flow budgets. Select MODFLOW | Flow Budget.... Review the flow data on the Cells and Zones tabs in the Flow Budget dialog. Generate water budget data on the USGS ZONEBUDGET tab.