After the creation of a baseline model, no slots can be added or deleted from the scenario slot list. This is done to preserve the integrity of the baseline model.

You have the following options:

The Scenario Sandbox is accessible from the RiverWare Workspace and from the Scenario Manager. If a Scenario Sandbox has been configured,

The Scenario Sandbox presents all the functionality necessary to create and run a scenario within a baseline model.

Next adjust values using the sliders for up to three scenario input slots. Changes to the sliders effect those input slots of the currently selected scenario.

Each input slot panel contains the following controls:

The Scale sliders are exponential. The range is based on the upper value set by the scenario engineer. The lower limit of the range is the reciprocal of the specified upper value. The mid-point is always “1”, which results in no difference from the baseline slot values.

The Offset sliders are linear, and range from the negative value to the positive value of the adjustment limit value set by the scenario engineer. The midpoint is always zero, which results in no difference from the baseline slot values. The Offset values are in the slot display units.

The computed scenario slot values are clipped at the configured minimum and maximum values for the baseline slot, if those have been configured.

The bottom section of the Scenario Sandbox shows generated scenario results (outputs). Output controls consist of three components:

The plot is dynamically updated as the selections in the two lists are changed. A curve is shown for each of the selected scenarios' value of the single selected output scenario slot. A curve for the baseline slot is always shown.

Only scenarios for which a scenario snapshot object has been generated are shown with a “Generated” timestamp. Double-clicking an item on the Generated Scenarios list shows the Open Object Dialog for that snapshot. Figure 8.2 illustrates.

Once a new scenario has been created, it must be saved. Use the File, then Save Scenario As and save the scenario in the desired directory. This can be loaded into subsequent BASELINE model runs for additional analysis.

For any particular scenario, full editing of Scenario input slots can be made available by unchecking the checkbox to the left of the Sandbox button on the Scenario Manager. When re-enabling the Sandbox for a scenario, if doing so would effect the values of those input slots, this warning message popup is displayed, providing the option to keep the Sandbox disabled (and preserve the scenario’s input slot values).

When a sandbox is not configured or you would like to change more than 3 input slots, you can create a scenario and have more control over the inputs. New scenarios to test permutations of the model can only use the slots specified in the scenario slot list, and all input values must fall within the minimum or maximum constraints (if any) set on the slot.

A tab with the name of the new scenario will be added next to the baseline tab in the Scenario Manager. Selecting the tabs allows you to toggle between the baseline scenario and other scenarios.

The name of the scenario corresponds to the scenario file’s name. A newly created scenario will have the default name “Unsaved Scenario.”

Finally, a convenient way to compare the differences between a slot in various scenarios is to plot the slot against either the baseline slot values or against the values of the slot in other scenarios. You can also plot the slot for a single scenario only. All the plotting options are located in the menu bar of the Scenario Manager under Slots, then Plot Slot, Slots, then Plot Slot + Baseline, or Slots, then Plot Slot on All Scenarios. The slots are plotted in the familiar RiverWare Plot dialog with all features of the Plot dialog active. A sample graphic is provided below, which compares the selected scenario slot with the baseline slot values. The scenario slot name is distinguished from the baseline slot name by the convention: Slot Name_Scenario Name_.

Running a scenario is fairly straight forward. The scenario with which you wish to run the model must be active. Open scenarios by selecting File, then Open Scenario.

There are two options for running an active scenario:

The Scenario Manager allows for comparisons between slots in the baseline scenario run and various scenario runs or between slots in the various scenario runs. Comparisons are managed through the Snapshot Manager and the Output Manager, which can be accessed through the Scenario Manager.

A snapshot object, or Scenario Output Snapshot Object, is automatically created after each scenario run (and also for the baseline run) to capture the values of a prescribed list of slots which generally represent outputs from the run. These new snapshot objects include copies of slots prescribed by the Scenario Engineer.

The association between a scenario and its output snapshot object is based only on the scenario and the object having the same name. This snapshot object will be saved with the scenario when the scenario is saved as a scenario file.

The background color of the snapshot object icon distinguishes the two types of snapshot objects:

If the Results to Compare (Output Slots) slot list described above is not empty, then, each time a run finishes or aborts, a Scenario Output Snapshot Object having the same name as the active scenario (or else, “BASELINE” in a non-scenario run) is created (or re-created) with the following data:

The automatically generated text lines within the snapshot object’s description begin with a special character (“>”) to distinguish them from user-entered comments. All such lines are deleted from the description before generating new comment lines.

The Open Object Dialog for the scenario’s output snapshot object can be shown by selecting the Output Slots button on the scenario’s tab in the Scenario Manager dialog or in the Scenario Sandbox; see Scenario Sandbox for details. These buttons are disabled if that snapshot object has not yet been generated.

Also, all existing Scenario Output Snapshot Objects are listed in the Snapshot Manager Dialog, with the snapshot items having a green-background snapshot icon.

Scenarios are saved in their own files, apart from the baseline model. The scenario’s output snapshot object is also saved in that file. When loading a scenario file, the snapshot object is loaded. This will replace any existing snapshot object on the workspace having the same name.