Decision Tables
Decision tables in SWAT+ define conditional logic for management operations. They specify conditions that must be met and the corresponding actions to execute. Decision tables are used in both land management and reservoir configurations.
Reviewing Decision Tables
To view decision tables, navigate to the Management section and select the Land Management or Reservoirs tab.
Attached Decision Tables
Decision tables attached to a management schedule appear in the 'Attached Decision Tables' section. Click on a table to view its conditions and actions.
Other Decision Tables
Expand the 'Other Decision Tables' section to see all available decision tables that are not currently attached to the selected management schedule.
Modifying Existing Decision Tables
Select a decision table to view its structure. The table displays: - Conditions (top rows): Logical tests like "If base plant heat units", "If soil water", "If julian day", "If rotation year" - Alternatives (alt1, alt2, etc.): Different combinations of condition states (>, <, =, -) - Actions (bottom rows): Operations to perform like "plant crop", "harvest (grain) and kill crop", "reset rotation to year 1"
Click the pencil icon to edit a condition or action, or the X to remove it.
Adding and Removing Conditions
Click '+ Condition' to add a new condition row to the decision table. Conditions define the logical tests that determine which alternative (alt) applies.
Adding and Removing Actions
Click '+ Action' to add a new action row. Actions define what operations are performed when the corresponding alternative's conditions are met.
Adding Alts
Click '+ Alt' to add a new alternative column. Each alt represents a unique combination of condition states and corresponding action responses.
Removing Alts
Use the trash icon next to an Alt number to remove that alternative column from the decision table.
Attaching Decision Tables
To attach a decision table to a management schedule:
- Click the 'Selection: A Decision Table to Attach' dropdown
- Select a decision table from the list (e.g., pl_hv_summer2, pl_hv_winter1, irr_opt_sw_unlim)
- Click the '+' button to attach it
To remove an attached decision table, click the 'X' next to its name in the Attached Decision Tables list.
Creating Decision Tables
Click '+ New Decision Table' to create a new decision table. You can then: 1. Add conditions that define when actions should occur 2. Add actions that specify what operations to perform 3. Configure alternatives with different condition/action combinations
Cloning Decision Tables
Click 'Clone Table' to create a copy of an existing decision table. This is useful when you want to create a similar table with minor modifications.
Purging Decision Tables
Use the 'Other Decision Tables' section to identify unused tables. Tables that are not attached to any management schedule can be safely removed to keep your project organized. purging can also be done automatically by clicking the purge buttton.