The Scenario Manager tool allows you to compare alternatives such as alternate model configurations, control strategies, or boundary conditions in a model. A model may contain up to 50 scenarios, which can be toggled on or off. Multiple scenarios are solved with a single command and results can be compared graphically in Review Results and in the XP Tables.
Scenarios may be defined as modifications to the base model. Child scenarios may then be developed from modifications to a previously defined scenario. The Scenario Manager stores model changes to the parent database for all modifications. These changes are stored in a Microsoft Access Database (*.mdb) file with the same base name as the xp project (.xp) file.
When the only difference between scenarios is rainfall, you should consider using the Global Storms tool described in Tutorial 10 - Creating Design Storms and Using Global Storms. We recommend that the Global Database should only be edited in the Base Scenario. Scenarios are not currently available in Sanitary Mode.
In this tutorial, the model is used to compare the performance of three culvert configurations:
- Base Scenario - 1 m diameter pipes with 3 barrels
- Box culvert - 1 m high x 2 m wide box culvert
- Double Box culvert - 1 m high x 2 m wide box culvert with 2 barrels
- Use the Scenario Manager to evaluate alternative configurations of a culvert
- Compare alternative configurations with Review Results and XP Tables
- Culvert_scenario01.xp (starter model)
- Yarra.dxf (background image)
- Launch the program and open the model.
- At the opening dialog, select Browse and navigate to the file Culvert_Scenario01.xp.
- Set the active mode to Hydraulics (Hdr).
- Navigate to the short network from node US Flows to node Outlet. Note that the network consists of a natural channel followed by a culvert under “Schlich Road” and then a downstream natural channel.
- Double-click the link Culvert to open the Multiple Link dialog. Note that the culvert is a 1 m diameter pipe and the over-topping of Schlich Road is represented as a broad crested weir. Click OK.
- Add CAD file:
- Check the visible box in the CAD Files line in the Layers Control Panel.
- Right-click the CAD Files line and select Load CAD File.
- Navigate to the file YARRA.dxf and click Open.
Toggle the check boxes to turn off the display of selected layers. Use the navigation tools to set the viewing area as shown in the figure below.
- Solve the model and review results:
- In the Analyze menu, select Solve. The simulation dialog will appear. Use this dialog to monitor the progress of the calculation.
Right-click link Culvert and select Review Results. The first graph displays results for the 1 m pipe. To view the road over-topping, click the Diversions tool. Note that flow over-tops the roadway with a peak flow about 0.56 m3/s at approximately 1:01 AM.
Click Edit next to the Scenario drop list to open the Scenario Manager dialog.
With the Base Scenario highlighted, click New. Change the title from Scenario_1 to Box Culvert.
With the Box Culvert scenario highlighted, click New to add an additional scenario called Double Box Culvert.
|Note that Box Culvert is a derivative of the Base Culvert and that Double Box Culvert is a child of Box Culvert. Make sure that the boxes for all three scenarios are checked. |
Click OK to close the dialog.
- Edit Box Culvert scenario.
- Set the Scenario drop list to Box Culvert.
- Double-click the multilink Culvert to open the Multiple Link dialog.
- Double-click Conduit 1 to open the Conduit Data dialog.
- Click Rectangular to open the Rectangular Conduit Data dialog.
- Set the Diameter (Height) to 1 m and the Width to 2 m. Check that the remaining data is as shown below, and then click OK.
In the Conduit Data dialog, double-click Conduit Factors to open the Special Conduit Factors dialog.
Check that the remaining data is as shown in the following dialog.
Click OK three times to return to the network view.
Edit the Double Box Culvert scenario.
Set the Scenario drop list to Double Box Culvert.
Double-click the multilink Culvert to open the Multiple Link dialog.
Double-click Conduit 1 to open the Conduit Data dialog.
Double-click Conduit Factors.
In the Special Conduit Factors dialog, set the Number of Barrels to 2.
Click OK three times to return to the network view.
- Review scenario data:
- Click Edit next to the Scenario drop list to open the Scenario Manager dialog.
- With the Box Culvert highlighted, click Properties.
- Review the Scenario Properties. This report lists the properties in a scenario that are different from the parent.
- Review the Double Box scenario report. Remember that Double Box Culvert is a child of Box Culvert so that it also has the properties of Box culvert and also those of the Base Scenario.
- Click OK twice to return to the network view.
Save your model as Culvert_Scenario02.xp.
- Solve and compare results:
- In the Analyze menu, select Solve.
- Click OK. Three output files will be automatically created with one for each scenario and one for the base. The scenario output files will be named with the scenario name appended to the output file name. The XPS 1D/2D Simulation dialog will appear. All three scenarios will be solved. Note that the lower progress bar represents a single scenario. The upper progress bar represents the complete solution.
- Right-click the link Culvert and select Review Results. The first graph displays results for the 1 m pipe. To view the road over-topping, click the Diversions tool.
- Use XP Tables:
- Launch the XP Tables by clicking the XP Table List tool.
- Review the Culvert Detail table. On the scenario drop list, select All Scenarios. Note the maximum flow over the weir (link Overtop) for each scenario. The maximum water surface elevation at Schlich Street is obtained from the last column. It is the upstream elevation for the Culverts link and the Overtop link.
- What is the hydraulic loading at node US Flows?
Constant flow ____ m3/s
Inflow hydrograph ____ m3/s peak, at ____ hours
- What is the maximum depth on Schlich Street for each scenario?
Base _____ m
Box Culvert _____ m
Double Box Culvert _____ m
- What is the total flow over the weir in each scenario? (Hint: see table E15a in the output files for each scenario).
Base _____ m3
Box Culvert _____m3
Double Box Culvert _____ m3