For an HEC-WAT FRA compute, the only results presented by HEC-WAT are the results from output variables. While the individual plugins actually compute the values, HEC-WAT presents those values instead of delegating that to a plugin. All other model alternative results that can potentially be accessed are provided by the plugins themselves. If the Save Model Results option is not selected in an HEC-WAT FRA compute, the results that would be presented by the plugins will not be available. In order to see detailed reporting of a specific event, re-run the event with the Save Model Folders option turned on to save event level output (refer to the Run FRA Simulation Dialog Box section in Computing Flood Risk Analysis Simulations). Alternatively, users can turn on the option for the entire simulation - this comes with the cost of potentially significant storage depending on the model alternatives in the compute sequence and how many events/lifecycles/realizations are included in a simulation.

Select Simulation

If an FRA simulation is active (displayed in a Simulation Map Window in the Desktop Pane), then the first item in the Results menu will be Select Results command.

HEC-WAT main window, displaying the available Results menu commands for an active FRA simulation.

However, if an FRA simulation is not active, then the Results menu displays one command, Select Simulation. The Select Simulation command opens the Select Simulation Results dialog box. From the Simulation list select the desired FRA simulation name and click OK. The Select Simulation Results dialog box closes and the selected simulation opens in a Simulation Map Window in the Desktop Pane.

Select Simulation Results dialog box.

Select Event Results

If the Save Model Folders option is on (from the Run FRA Simulation dialog box, see Computing Flood Risk Analysis Simulations), results from model alternatives that ran during the simulation are accessible. To review results, the individual event for which results are desired must be selected. From the Results menu in the HEC-WAT main window, click Select Results, and the Select Event Results dialog box opens. Select the realization, lifecycle, and event for which results are desired.

Select Event Results dialog box.

Then from the HEC-WAT Results menu, the user can access results from the different plugins that have been defined in the FRA simulation. The available commands from the Results menu for an FRA simulation depend on the model alternatives in the simulation. For example, the Fragility Curve and Performance Metrics only appear in the Results menu for an active FRA simulation containing a fragility curve and performance metrics model alternative.

Example of the Results menu for an FRA simulation containing fragility curve and performance metrics model alternatives.

Lifecycle DSS File

In an FRA compute, results from the model alternatives are stored in the DSS file that is stored in each lifecycle folder (lifecycle.dss) of a realization. If the Save Lifecycle DSS option is turned on, the model output from the plugins in the program order that are DSS-based is stored for review. Since this can create a significant amount of storage, take care in turning on this option for large models and FRA simulations. 

Simulation DSS File

Output Variables generated by the FRA specific model alternatives are stored in the simulation.dss file as well as random numbers, frequency curves, and stratification weights. To access the Simulation DSS file, click Simulation DSS File in the Results menu; a HEC-DSSVue window opens with the DSS file of the active simulation displayed. Using the HEC-DSSVue interface, the user can view results. 

HEC-DSSVue window displaying the simulation.dss file for an example Flood Risk Analysis, FRA, simulation.

Output Variables

There are three options for visualizing output variables – Variable Viewer, Histogram Viewer, and Frequency Viewer.

Variable Viewer

The Variable Viewer provides scalar plots of the user-selected output variable from the Variable list for each selected realization (Realization list) and lifecycle number (Lifecycle list). The Lifecycle list does include an option to view all lifecycles within a realization. The Output Variable Viewer displays the output value (y-axis) for each event (x-axis) in the selected life cycle or from all life cycles in the selected realization. The Output Variable Viewer can be used to quickly identify outliers in the model results that might require additional investigation. For example, the user has chosen the output variable to plot a histogram for Realization 6, and all its lifecycles.

Output Variable Viewer, example plot.

Histogram Viewer

The Histogram Viewer provides histogram plots of the user-selected output variable from the Variable list for each selected realization (Realization list) and life cycle number (Lifecycle list). The Lifecycle list does include an option to view all lifecycles within a realization. The Histogram Viewer provides the user with a quick way to visualize the range of values (x-axis) for the selected model results and the relative probability (y-axis). For example,  the user has chosen the output variable to plot a histogram for Realization 6 and all of its lifecycles.

Histogram Viewer, example histogram.

Frequency Viewer

The Frequency Viewer option only displays output variables which had the frequency option turned on. From the Results menu in the HEC-WAT main window, select Output Variables, choose Frequency Viewer, the Frequency Viewer opens.

Frequency Viewer, example default selection.

The Frequency Viewer by default displays the first defined output variable in the Variable list that had the frequency option selected. The confidence intervals and the first realization in the Realization list are displayed by default for that output variable. Any output variable with the frequency curve option turned on can be viewed with this viewer. For example, to view the three-day average maximum flow frequency curves for all realizations for a particular location, from the Variable list, click Upstream Boundary Conditions – AVG 3 DAY Max Flow (results generated by the hydrologic sampler). To view all realizations, select All Realizations from the Realization list. The Frequency Viewer displays the frequency curves at the selected location for all realizations in the simulation with confidence intervals. 

Frequency Viewer, example Variable list options.

Frequency Viewer, displaying All Realizations for the selected location.

By using the Navigator Tool , the user can click through the output variables that have been defined, instead of making a selection from the Variable list.

An additional example below displays the frequency curve for All Realizations at Sayers Inflow Jct for the Average 3 day maximum flow. A separate frequency curve is plotted with results from each realization plus the combined frequency curve and the 5 and 95 percent confidence limits for the combined curve.

Frequency Viewer, example plot.

Plugin Results

To view results generated by an HEC-WAT plugin (e.g., Hydrologic Sampler), review the plugin-specific documentation at HEC-WAT Documentation.