Scenario Input Sets

Scenario input sets allow you to easily keep model structure, while switching between groups of input data and parameters. These may be used to represent changeable physical attributes, such as climate, land use decisions or even proposed infrastructure characteristics. You can switch between different scenario input sets to compare the effects on a model. For example, you can have one scenario input set consisting of rainfall, inflow and evapotranspiration data for natural conditions, another for wet conditions and a third set for dry conditions.

You choose the scenario input set used for a run using the Scenario Input Set drop-down menu in the Configure dialog (Figure 1), accessed by clicking Configure on the simulation toolbar.

Figure 1. Configure, choose scenario input set. 

Scenario input sets are created and managed using the Scenario Input Sets dialog, which is accessible via Edit » Scenario Input Sets... (Figure 2).

Using the panel on the left, then right-clicking, you can do the following using the contextual menus:

• Add Scenario Input Set – create new scenario input set;
• Set Default – select this scenario input set to be the default;
• Add Child Scenario Input Set – create a new child scenario input set.
  
• Rename – change the name of a scenario input set; and
• Delete – remove a scenario input set.

Scenario input sets can define both input parameters and data sources. Input parameters specific to a scenario are defined in the Scenario Input Set dialog, either manually or using a file. Data sources are assigned to scenario input sets using the Load Data Source dialog, as explained here.

Figure 2. Scenario input sets, parameter entry

Input parameter entry

Parameters specific to a scenario input set are defined and managed using the parameter set editor in the Scenario Input Sets dialog (as shown in Figure 1). The panel on the right allows you to specify parameters, either manually, or by loading a text file.

The general format for a parameter is: path1.path2...pathN=value (eg. Nodes.Inflow1.Flow=10 ML/d).

Manual entry

Figure 1 shows an example of manual parameter entry using the manual parameter set editor. This editor has the following features:

• An auto-complete functionality that is activated when an accepted scenario base node is entered for the first element of the path;
• Typing additional characters filters the auto-completion list. Pressing Tab or Return auto-fills an element from the auto-completion list;
• Pressing the period character ('.') displays a list of valid elements for the next step in the path;
• For a valid path, pressing the equals character ('=') displays candidate values;
• Click the Insert units icon for a list of available units. Note that these are not scenario-dependent so you must choose the correct item; and
• An invalid parameter is identified with an underline (illustrated in Figure 2 for the Loss 3 node, which was deleted after the parameter was created). Acceptable parameter types are provided in Table 1.

Table 1. Types of parameter values

File-based parameter specification

The file-based parameter entry (shown in Figure 2) allows the specification of a file that will contain the element path and values. The formatting of this file must adhere to the same rules as the manual parameter set editor.

Note that the Reload on Run and Relative path checkboxes follows the same rules as for data sources.

Figure 3. Input parameter set using a file

Child Scenario Input Sets

Child scenario input sets allow you to further refine model scenarios. A child scenario input set inherits all parameters and data sources specified in its parent. You can then set additional parameters, or alter existing ones. When you run a model with a child scenario input set, for any parameters that differ between the parent and child, the parameters from the child will take precedence.

Figure 4. Child Scenario Input Sets, Example

For parent and child scenario input sets:

• You can create 'grandchildren', thus creating nested scenario input sets. Every child scenario input set inherits all parameters above it in its branch, and ignores any parameters set in its children. 
• Data sources can only be assigned to the root-level parents (Dry Weather, Wet Weather and Default Input Set in Figure 4).
• Deleting a parent will delete all of its children.