Scenario Comparison tools allows to compare model results of different scenarios at a certain location. For example, you could compare the peak flow at your site outlet from pre-development condition and post-development condition with a pond. Engineers could setup the comparison in the submitted model for reviewers to open directly for verification. This tool is available for both single-event and continuous simulation.

To use the Scenario Comparison tool:

1. Navigate to Simulation toolbar and click the Scenario Comparison button

2. In the popped-up window choose the Design Storm from the drop-down list, check off the Scenarios that you want to include the Graph and Statistics table, and select the Command that you are interested to make a comparison.

For RouteWetland command, there are two extra tabs called Hydroperiod and Inflow Mass Curve for Continuous project. In those two tabs, VO uses the results of one pre-development scenario to calculate difference from the other scenarios to the pre-development scenario. Therefore, before doing the scenario comparison, users should select one scenario from all the scenarios in the project as the Pre-Development Scenario. By default, the first scenario under the Drainage Network Scenarios in the Project Manager is the pre-development scenario. To assign any scenario as the pre-development scenario, select and right-click on the desired scenario under the Drainage Network Scenarios group in the Project Manager. In the opened context menu, click on Set as Pre-Development Scenario

Open Scenario Comparison and choose RouteWetland command. Click on Hydroperiod or Inflow Mass Curve to see the comparison. The grey lines in the graph of Hydroperiod are the the upper and lower boundaries of the confidence interval. You can change the Year to be compared and the desired Confidence Interval (%) from the drop-down list. Below the graph is the Statistics table summarizing the days when the Storage depth of the RouteWetland is out of the confidence interval for each scenario in the selected year.

For RouteChannel command, there is an extra tabs called Erosion Indices for Continuous project. The Erosion Indices compares RouteChannel results in three erosion indices: Time of Exceedance, Cumulative Erosion Index and Cumulative Effective Work Index. Before doing the comparison, users should also assign the pre-development scenario as described above. Open the Scenario Comparison and choose RouteChannel command. Click on the Erosion Indices tab. In the drop-down window of Type, choose one index from the three erosion indices to be compared. Type the parameters and click Update. The Graph and the Statistics table will be updated.

Please note that it may take a while to show the results of Cumulative Effective Work Index.

User input parameters required for each index:
Time of Exceedance: Critical velocity
Cumulative Erosion Index: Critical velocity
Cumulative Effective Work Index: Critical Shear Stress, Coefficient

3. Export the Statistics table as a CSV file by clicking the Export button

4. Click the Save button. In the popped-up window, type a name for the comparison chart.

5. The current Scenario Comparison will be saved in the Project Manager under the Scenario Comparison group . To open the same scenario comparison, simply double click on the saved item.