Managing HEC-ResSim Model Alternatives
An HEC-ResSim model alternative includes:
- A watershed schematic
- A stream and reservoir network
- Operational rules for each reservoir
This guide will teach you how to create and manage HEC-ResSim model alternatives in your HEC-RTS watershed.
Build your HEC-ResSim model and its associated alternatives within the HEC-ResSim software to ensure correct setup before integrating them into your HEC-RTS watershed.
Importing an HEC-ResSim Watershed
To import an HEC-ResSim watershed:
Go to the Setup tab.
Right-click the HEC-ResSim icon in the Watershed Tree and select Import.
- The Import Type dialog will appear.

- Select Watershed to import the watershed data (including stream alignment, network, configurations, and alternatives).
- In the file browser, locate and select the HEC-ResSim watershed file (.wksp), then click Open.
- The import process starts automatically, and an Import Progress dialog appears.
- When finished, the dialog closes, and the Message window displays ResSim Import Complete.
- Save your watershed.
It is recommended that you import the entire watershed first to establish your stream alignment.
Importing an HEC-ResSim Alternative
To import an alternative:
- In the Setup module’s Watershed Pane, right-click the HEC-ResSim icon and select Import.
- In the Import Type dialog, click Alternative to open the Import Alternative Wizard.

- Click the ellipsis next to Watershed File, browse to the .wksp watershed file, select it, and click OK.
- Click Next to proceed.
- From the Available Alternatives table, select the alternative you want and click Next.
- Enter a name and description for the new alternative, then click Next.
- Enter a name and description for the new reservoir network, then click Next.
- Assign stream names in the To Stream column and click Next.
- If necessary, select watershed computation points and click Next.
- Review the import summary. You may copy or print it if desired.
- Click Finish, confirm by selecting Yes to continue.
- Save your watershed.
Editing an HEC-ResSim Alternative
To edit an alternative:
- Go to the Setup tab.
- From the Watershed Tree, right-click an HEC-ResSim alternative and choose Edit Alternatives.
- Make the desired changes in the ResSim Alternative Editor.
- For detailed instructions, refer to the HEC-ResSim User's Manual.
- Save your changes by selecting Save from the Alternative menu.
- Close the editor.
- Save your watershed.
Copying an HEC-ResSim Alternative
To copy an alternative:
- Go to the Setup tab.
- In the Watershed Tree, right-click an HEC-ResSim alternative and select Edit Alternatives.
- In the ResSim Alternative Editor, choose Save As from the Alternative menu.
- In the dialog, enter a new name (required) and a description (optional).

- Click OK. The copied alternative appears in the editor and in the Watershed Tree.
- Save your watershed.
Deleting an HEC-ResSim Alternative
To delete an alternative:
- Go to the Setup tab.
- In the Watershed Tree, right-click an HEC-ResSim alternative and select Edit Alternatives.
- From the Alternative menu in the ResSim Alternative Editor, select Delete.
- Confirm by clicking Yes.
- Close the editor.
- Save your watershed.